Agricultural Science
for CSEC® Examinations
Marion Perrett-Pearson
Ronald Ramharacksingh
CSEC® is a registered trademark of the Caribbean Examination Council (CXC).
Agricultural Science for CSEC ® Examinations is an independent publication and has
not been authorised, sponsored, or otherwise approved by CXC.
Macmillan Education
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London N1 9XW
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Companies and representatives throughout the world
ISBN 978-1-380-05465-4
Text © Marion Perrett-Pearson and Ronald Ramharacksingh 2020
Design and illustration © Macmillan Education Limited 2020
The authors have asserted their right to be identified as the authors of this
work in accordance with the Copyright, Designs and Patents Act 1988.
First published 2011
This edition published 2020
All rights reserved. No part of this publication may be reproduced, stored in
a retrieval system, or transmitted in any form or by any means, electronic,
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written permission of the publishers.
Designed by Macmillan Education
Page make-up by Ink Design
Illustrated by Angie Bowring, Sean Chris Strydom and Bev Victor
Cover design by Macmillan Education
The publishers would like to thank our team of advisors, who have been
instrumental in providing Caribbean content, and local teaching and
agricultural practices:
• Simon Drakes (Presentation Brothers’ College, Grenada)
• Sylvia JnoBaptise (St Mary’s Academy, Dominica)
• Suzette Johnson (Tacius Golding High School, Jamaica)
• Carlington Lindsay (McGrath High School, Jamaica)
• Makela Oblington (Brazil Secondary School, Trinidad)
Students of Agricultural Science from Grenville Secondary School
(Grenada), Presentation Brothers’ College (Grenada), Brazil Secondary
School (Trinidad) and St Andrew Technical High School (Jamaica)
provided valuable feedback on the book’s design and overall approach to
help create a student-friendly and engaging text.
The publishers would also like to thank CARDI (Trinidad), Genaro Chiac
(Belize), John Jogie (Grenada) and Tyrone Sankar (St Lucia) for providing
relevant and up-to-date examples of Agricultural Science in the real world.
Thanks also go to the following agricultural sites for facilitating research
visits: Sugarcane Feeds Centre (Trinidad), CARDI (Trinidad and Grenada),
UWI Field Station (Trinidad), Mirabeau Propagating Station and Farm
School (Grenada), Diamond Chocolate Factory (Grenada), River Antoine
Estate (Grenada), Dal Douglas Farm (Grenada), Golden Dutchy Farm
(Jamaica), Ebony Park (Jamaica) and Bogles Research Station (Jamaica).
Printed and bound in Spain
2024 2023 2022 2021 2020
987654321
The authors and publishers would like to thank the following for permission to reproduce their photographs:
Alamy Stock Photo/Suzanne Long / Alamy Stock Photo p33, The Oxfordshire Chilli Garden / Alamy Stock Photo p121, blickwinkel / Alamy Stock Photo
(tl) p132, Humberto Olarte Cupas / Alamy Stock Photo (bl) p132, Rob Fenenga / Alamy Stock Photo p133, Freeman Keats / Alamy Stock Photo p367,
iStock / Getty Images Plus/Jaykayl (tl) p152, iStock / Getty Images Plus/jess311 (tr) p152; Getty Images Filisteen Khan p324, Getty Images/Robert Daly
p387, Getty Images/kate_sept2004 p397; Science Photo Library UK Crown Copyright Courtesy of Fera / Science Photo Library p192; all other photos
courtesy of the author.
The following farmers supplied photographs for use in this edition:
• Drone photos: Neil and Sarah Robson, GM & LD Robson, Barratts Cottage Farm, Marton, Warwickshire CV23 9RN
• Butchery photos: Graham Marshall (butcher) at A & N Ellis & Sons, Hilltop Farm Shop and Butchers, Fosse Way, Hunningham, Leamington Spa,
Warwickshire CV33 9EL
• Digger with crawler tracks photo: Tim Parton, SS & SD Kirk, Brewood Park Farm, Coven, Wolverhampton, Staffordshire WV9 5BW
• Digital weather station information and photo: Simon Deacon, JW & BA Deacon & Son, Top Barn Farm, Rugby Road, South Kilworth, Leicestershire
LE17 6DW
• Variable rate Nitrogen, nutrient mapping and data management tools: Jim Reeve, Newfields Farm, Shakers Lane, Long Itchington, Southam,
Warwickshire CV47 9QB
• Cattle with sensors and feeding trough with scale photos: Henry Dingle, Moreton Morrell College Farm (Nethermoreton Farm), Warwick New Road,
Warwick, Warwickshire CV32 5JE
The authors and publishers are grateful for permission to reprint the following copyright material:
P14 Percentage of land used for agriculture provided by World Bank data. © 2019 The World Bank Group. https://data.worldbank.org/
P251 Extract from ‘Ishemo, Amani and Bushell, Brenda (2017). Farming Cooperatives: Opportunities and Challenges for Women Farmers in Jamaica’.
Journal of International Women’s Studies, 18(4), 13–29.)
These materials may contain links for third party websites. We have no control over, and are not responsible for, the contents of such third party websites.
Please use care when accessing them.
Contents
About the authors............................................................................................................................................ vi
Advisors and contributors................................................................................................................................ vi
Preface............................................................................................................................................................... vii
How to use this book....................................................................................................................................... viii
Section A: Introduction to agriculture 1
Unit 1
Agricultural science and agriculture.................................................................................................................
1.1The relationship between agriculture and agricultural science...........................................................
1.2The history of agriculture in the Caribbean...........................................................................................
1.3Non-conventional and conventional crop systems................................................................................
1.4The principles of organic farming...........................................................................................................
1
2
2
3
5
Unit 2
Role of agriculture and support services..........................................................................................................
2.1The importance of agriculture in national, regional and international economies...........................
2.2 Types of agricultural enterprises.............................................................................................................
2.3Institutions concerned with agricultural development in the Caribbean............................................
11
12
15
16
Unit 3
Challenges in agriculture...................................................................................................................................
3.1 Local and regional challenges.................................................................................................................
24
25
Section B: Crop production 37
Unit 4
Anatomy and physiology...................................................................................................................................
4.1 The uses of plants in agriculture.............................................................................................................
4.2 The structure of plants.............................................................................................................................
4.3 Plant processes..........................................................................................................................................
4.4 Sexual and asexual reproduction in plants.............................................................................................
4.5 Techniques used in plant propagation...................................................................................................
4.6 Conditions necessary for germination....................................................................................................
37
38
38
44
49
53
56
Unit 5
Environmental factors affecting crop growth..................................................................................................
5.1 Effects of environmental factors on plant growth and development.................................................
5.2 Process of soil formation..........................................................................................................................
5.3 The importance of a soil profile..............................................................................................................
5.4 The major components of soil.................................................................................................................
5.5 The physical and chemical properties of major soil types.....................................................................
5.6 The availability of soil water for crop use..............................................................................................
5.7The importance of major and minor nutrients used in crop production.............................................
5.8 The factors affecting soil fertility............................................................................................................
5.9 Maintaining soil fertility..........................................................................................................................
5.10 Soil and water conservation methods....................................................................................................
64
65
66
68
69
71
77
78
81
84
89
Unit 6
Plant genetics, breeding and biotechnology.................................................................................................... 95
6.1 The principles of genetic inheritance..................................................................................................... 96
6.2 The role of plant breeding...................................................................................................................... 97
6.3 Biotechnology in plant improvement..................................................................................................... 102
Unit 7
Land preparation and farm machinery............................................................................................................. 107
7.1 Land preparation methods...................................................................................................................... 108
7.2 The importance and functions of machinery used in crop husbandry................................................. 111
7.3 Safety precautions when operating tools, machinery and equipment................................................ 114
7.4Care and maintenance of tools and equipment.................................................................................... 116
Contents
Unit 8
Crop management.............................................................................................................................................. 120
8.1 Cultivation of crops.................................................................................................................................. 121
8.2 Major cropping systems........................................................................................................................... 123
8.3 Cultural practices associated with crop production............................................................................... 126
8.4 The effects of weeds on crop production............................................................................................... 127
8.5 Methods of weed control........................................................................................................................ 128
8.6 Pests and crop damage............................................................................................................................ 130
8.7 Major crop diseases.................................................................................................................................. 132
8.8 Chemicals in the environment................................................................................................................. 133
8.9 Pest and disease management................................................................................................................ 135
8.10 The importance of plant quarantine...................................................................................................... 138
Unit 9
Harvesting and post-production management................................................................................................ 141
9.1 Harvesting crops....................................................................................................................................... 142
9.2 Harvesting methods................................................................................................................................. 143
9.3 Post-harvest handling procedures........................................................................................................... 144
9.4 Post-harvest management....................................................................................................................... 145
Section C: Animal production 150
Unit 10 Introduction to animal sciences......................................................................................................................... 150
10.1 Breeds of farm animals............................................................................................................................ 151
10.2 Uses of different breeds of farm animals............................................................................................... 152
10.3 Species of fish and bees........................................................................................................................... 153
Unit 11 Structure, anatomy and physiology.................................................................................................................. 156
11.1The structures and functions of the digestive systems of non-ruminants and ruminants.................. 157
11.2 The process of digestion.......................................................................................................................... 159
Unit 12 Nutrition and management............................................................................................................................... 165
12.1 The ‘complete ration’............................................................................................................................... 166
12.2 Rations for broilers and layers................................................................................................................. 166
12.3 Feed conversion ratio (FCR)..................................................................................................................... 167
12.4 The importance of FCR............................................................................................................................. 168
12.5 Systems of grazing................................................................................................................................... 168
12.6The importance of forages in livestock feeding.................................................................................... 172
12.7 Feeding ruminants when forage is unavailable..................................................................................... 176
12.8 The care of young chicks and rabbits..................................................................................................... 177
12.9Management practices associated with rearing broilers, layers and rabbits....................................... 179
12.10 Rearing a batch of broilers...................................................................................................................... 180
12.11 Animal health........................................................................................................................................... 180
12.12 Pests and diseases of poultry and rabbits: symptoms, prevention and control................................... 181
12.13Pests and diseases of livestock: symptoms, prevention and control..................................................... 182
Unit 13 Fish and bee management................................................................................................................................. 186
13.1 Factors in establishing and managing a fish farm................................................................................. 187
13.2 Factors for the keeping of bees.............................................................................................................. 190
13.3 Economic importance of keeping bees .................................................................................................. 190
13.4 The types of bees in a hive...................................................................................................................... 191
13.5 The social activities of bees..................................................................................................................... 192
13.6 Pests and diseases of bees....................................................................................................................... 193
13.7 Honey and other bee products............................................................................................................... 193
Contents
Unit 14 Animal genetics, breeding and reproduction.................................................................................................. 198
14.1 Breeding systems in animal production.................................................................................................. 199
14.2 Advantages of cross-breeding................................................................................................................. 200
14.3Genetic engineering in livestock production......................................................................................... 203
14.4 Terms used in animal reproduction......................................................................................................... 205
14.5 Artificial insemination in farm animals.................................................................................................. 208
14.6Advantages and disadvantages of artificial insemination.................................................................... 209
14.7 The structure of an egg........................................................................................................................... 210
14.8 Egg formation and incubation in poultry.............................................................................................. 210
Unit 15 Animal products.................................................................................................................................................. 215
15.1 Slaughtering procedures.......................................................................................................................... 216
15.2 The dressing percentage of farm animals.............................................................................................. 217
15.3 Animal products and by-products........................................................................................................... 218
15.4Rearing layer birds and the production of eggs.................................................................................... 222
Section D: The business of farming 226
Unit 16 Economic factors of production........................................................................................................................ 226
16.1Factors of production related to agriculture.......................................................................................... 227
16.2 Concepts of the value and supply chains............................................................................................... 230
16.3The relationship between production, marketing and consumption.................................................. 231
16.4 Demand, supply and price relationships................................................................................................. 233
16.5 The ‘law of diminishing returns’............................................................................................................. 238
Unit 17 Farm financing and support services................................................................................................................. 245
17.1 Obtaining capital...................................................................................................................................... 246
17.2 Cooperatives............................................................................................................................................. 249
17.3 Incentives available to farmers................................................................................................................ 252
Unit 18 Farm organisation and planning....................................................................................................................... 256
18.1 Preparing different types of farm records.............................................................................................. 257
18.2 Income and expenditure.......................................................................................................................... 260
18.3 Complete and partial budgets................................................................................................................. 262
Unit 19 Marketing of agricultural products................................................................................................................... 267
19.1The role of marketing in agricultural production................................................................................. 268
19.2 The steps of marketing............................................................................................................................ 269
19.3 The process of marketing agricultural products.................................................................................... 270
19.4The importance of international trade agreements.............................................................................. 271
Section E: Farm management technologies 277
Unit 20 Environmental monitoring................................................................................................................................. 277
20.1Using appropriate technology to collect environmental data.............................................................. 278
20.2 Analysing environmental data................................................................................................................ 279
20.3 Applying environmental data to decision-making................................................................................ 282
20.4Use of appropriate technologies for conservation of environmental resources................................. 286
Unit 21 Nursery management technologies.................................................................................................................. 291
21.1 Preparation of compost........................................................................................................................... 292
21.2 Prepare propagation and growing media.............................................................................................. 294
21.3 Proper handling procedures for different types of media.................................................................... 297
21.4 Assess seed quality................................................................................................................................... 299
21.5 Suitable seed storage procedures........................................................................................................... 301
21.6 Proper procedures and choice of equipment for establishing plants in a nursery................................. 302
Contents
Unit 22 Technologies for non-conventional crop production....................................................................................... 307
22.1 The importance of alternative crop production systems in the Caribbean......................................... 308
22.2Crop cultivars that are tolerant or resistant to specific abiotic and biotic stresses............................. 311
22.3 Design a suitable cropping system.......................................................................................................... 313
22.4 Strategies for water and nutrition management.................................................................................. 315
22.5 Simple water and nutrition management technologies....................................................................... 317
22.6Integrated pest management.................................................................................................................. 318
22.7 Pest management technologies.............................................................................................................. 318
Unit 23 Management practices for livestock................................................................................................................. 323
23.1 Caring for young farm animals............................................................................................................... 324
23.2 Housing requirements for farm animals................................................................................................. 324
23.3 Housing for broilers, layers and rabbits.................................................................................................. 326
23.4 Good agricultural practices to avoid pests and disease in livestock..................................................... 328
23.5 Control measures for pests and diseases................................................................................................ 330
23.6 Biotechnology in animal production...................................................................................................... 332
Unit 24 Harvesting, post-harvesting management and value addition....................................................................... 336
24.1 Correct stage for harvesting.................................................................................................................... 337
24.2 Appropriate harvesting procedures........................................................................................................ 338
24.3 Appropriate harvesting technology........................................................................................................ 339
24.4 Post-harvest management systems......................................................................................................... 340
24.5 Proper post-harvesting procedures......................................................................................................... 344
24.6Processes for adding value to the crop produced.................................................................................. 344
Unit 25 Post-production handling and processing of livestock.................................................................................... 349
25.1 Processes used to prevent food spoilage................................................................................................ 350
25.2 Principal cuts of meat............................................................................................................................... 351
25.3 Safety requirements for food processing............................................................................................... 354
25.4 The use of animal by-products and waste in value-added products.................................................... 356
Unit 26 Agro-engineering............................................................................................................................................... 360
26.1 Designing farm structures ....................................................................................................................... 361
26.2 Suitable materials for farm buildings..................................................................................................... 362
26.3 Safety precautions in the operation of tools, machinery and equipment........................................... 362
26.4The use and operation of mechanical systems in farm equipment...................................................... 365
26.5Care and maintenance of simple tools and equipment........................................................................ 366
Section F: Entrepreneurship and communication 371
Unit 27 Entrepreneurship in agriculture........................................................................................................................ 371
27.1 The concept of entrepreneurship............................................................................................................ 372
27.2 Forms of business organisations.............................................................................................................. 373
27.3 Establishing an agricultural enterprise................................................................................................... 375
27.4 The importance of SWOT analysis in decision-making for agricultural enterprises............................ 379
27.5 Factors that contribute to success and failure....................................................................................... 380
27.6 The purpose of key financial statements in decision-making............................................................... 382
Unit 28 Communication in agri-business........................................................................................................................ 386
28.1Channels of communication used in agricultural enterprises............................................................... 387
28.2 Factors affecting the selection of a communication channel............................................................... 389
28.3 Barriers to effective communication....................................................................................................... 390
28.4 Advantages and disadvantages of different communication tools and technologies........................ 392
28.5 Communicate effectively for different purposes within and outside the food
and agriculture sector.............................................................................................................................. 397
Answers to ITQs................................................................................................................................................ 401
School-Based Assessment................................................................................................................................ 408
Index.................................................................................................................................................................. 416
About the authors
About the authors
Marion Perrett-Pearson (MSc, PG Cert Food Security) is an Agricultural Advisor for Severn Trent, a UK water
company. She is responsible for protecting two river catchments from farming pollution; this is an area of about
2 000 km². Marion advises farmers on reducing the chemical and nutrient pollution that washes into these rivers.
Many of the precision farming methods that reduce agricultural pollution are described in this book. Marion is a
qualified teacher and has previously worked as a Head of Geography in secondary schools in the UK and Sudan.
She was the Chief Examiner of GCSE Agriculture and Land Use for the CCEA in Northern Ireland. She is also a
photographer, and took many of the photos for this book while in the Caribbean.
Ronald Ramharacksingh (Dip Agric; Adv Dip Tech Teacher Training; BSC (Hons) Agric; MA Agric Ed) is an
experienced educator, trainer and agriculturalist. He has been involved continuously in education, teacher training
and examinations, as well as supervision, curriculum development and consultancy, locally and regionally, for
more than 45 years.
Dr Mike Taylor has been actively involved in education and teaching, at school and university level, for over
40 years. He has considerable experience of teacher training and has examined science at ‘O’ and ‘A’ levels all over
the world.
Advisors and contributors
This book was produced in close consultation with advisors from across the Caribbean, who have been instrumental
in providing Caribbean content, and local teaching and agricultural practices:
• Simon Drakes (Presentation Brothers’ College, Grenada)
• Sylvia JnoBaptise (St Mary’s Academy, Dominica)
• Suzette Johnson (Tacius Golding High School, Jamaica)
• Carlington Lindsay (McGrath High School, Jamaica)
• Makela Oblington (Brazil Secondary School, Trinidad)
Local case studies have been sourced from across the Caribbean, including contributions by CARDI, Genaro Chiac
(Belize), John Jogie (Grenada) and Tyrone Sankar (St Lucia), providing relevant and up-to-date examples of
Agricultural Science in the real world.
Students of Agricultural Science from Grenville Secondary School (Grenada), Presentation Brothers’ College
(Grenada), Brazil Secondary School (Trinidad) and St Andrew Technical High School (Jamaica) provided valuable
feedback on the book’s design and overall approach to help create a student-friendly and engaging text.
The following farmers supplied photographs for use in this edition:
• Drone photos: Neil and Sarah Robson, GM & LD Robson, Barratts Cottage Farm, Marton, Warwickshire
CV23 9RN
• Butchery photos: Graham Marshall (butcher) at A & N Ellis & Sons, Hilltop Farm Shop and Butchers, Fosse
Way, Hunningham, Leamington Spa, Warwickshire CV33 9EL
• Digger with crawler tracks photo: Tim Parton, SS & SD Kirk, Brewood Park Farm, Coven, Wolverhampton,
Staffordshire WV9 5BW
• Digital weather station information and photo: Simon Deacon, JW & BA Deacon & Son, Top Barn Farm, Rugby
Road, South Kilworth, Leicestershire LE17 6DW
• Variable rate Nitrogen, nutrient mapping and data management tools: Jim Reeve, Newfields Farm, Shakers
Lane, Long Itchington, Southam, Warwickshire CV47 9QB
• Cattle with sensors and feeding trough with scale photos: Henry Dingle, Moreton Morrell College Farm
(Nethermoreton Farm), Warwick New Road, Warwick, Warwickshire CV32 5JE
vi
Preface
Preface
Modern farming is more and more a team effort. Agriculture is increasingly a local, regional, national and
international effort. A great deal of expert support is available, both agricultural and financial, and this book will
help readers to use it to their best advantage.
As the 21st century progresses there is greater emphasis on the farmer’s role as a business person and entrepreneur,
not only in large-scale enterprises but also where the farm may be a family undertaking. If this book helps to
maintain a love of farming and encourages readers to succeed in it and enjoy the fulfilment it can bring, it will be
a success.
This new edition has been constructed with the needs of the latest CSEC syllabus in mind. The book covers the
requirements of both the single and double awards and the changes in order and importance of topics, between
the old and the more recent.
The edition draws on material from the first edition where this is still applicable, but new material has been carefully
written to cover the demands of the technological age and the increasing importance personal and corporate
initiative.
The format of the new book has been retained from the familiar previous edition, but with amendments designed
to make the book easier to use as a text and a revision aid. There are short-answer questions (called In-text
Questions, ITQs) that allow readers to test their grasp of the current topic. If you can answer, good! If you cannot,
go back over the section and try again. Diagrams and pictures are placed on the page in such a way that they can
readily be consulted, but interrupt the text as little as possible – a framework that will be maintained for every book
in the Science series.
Dr Mike Taylor
Series Editor
vii
How to use this book
How to use this book
The second edition of Agricultural Science for CSEC Examinations includes a wealth of pedagogical features to support
teaching and to engage students. Each unit opens with a checklist of objectives and a concept map to show
students what they are going to learn. Within each unit are real-life case studies from across the Caribbean, intext questions to check comprehension, and practical activities for hands-on practice inside, outside and online.
Key terms are also highlighted where they are defined – an index at the back helps shows where these can be
found. Each unit ends with examination-style questions to help students to prepare, and a new revision map
feature that shows how concepts link together. At the back of the book is a sample SBA project to show students
what they need to do to achieve top marks. There is also additional SBA guidance for teaching available online at
www. macmillan-caribbean.com.
Concept maps
Unit openers
Key words
Themes
ITQ 1
key terms ▶ Key terms are highlighted where they are
What does ITQ stand for?
defined in the text like this. There is also an
index at the back of this book that shows each
usage and where to find the definition.
Answers to ITQs
‘ITQ1’ ITQ stands for in-text question.
The questions appear in the
margins. You can find the
answers at the back of the book.
Examination-style questions
Multiple-choice questions
Practical activities:
Look out for these boxes in the margins of each unit.
They provide hands-on activities for students to practise
concepts outside, in the classroom or online.
appear at
the end of
each unit
Revision
maps
summarise
and link
topics
consolidate knowledge
help students prepare for assessment
are useful homework tasks
all of the above.
The introduction to the SBA and model
sample project at the back of the book
shows students how their work should be
approached. Detailed guidance to potential
projects is provided for teachers online at
www. macmillan-caribbean.com.
Case studies
studentfriendly way to
organise notes.
viii
A.
B.
C.
D.
Real-life case studies from across the Caribbean
featuring in every unit to help students engage
with relevant and up-to-date examples of
agricultural science in practice.
Section A: Introduction to agriculture
1
Agricultural
science and
agriculture
By the end of this unit you should be able to:
✔ explain the relationship between agriculture and agricultural science
✔ explain the history of agriculture in the Caribbean
✔ describe conventional and non-conventional crops and livestock
farming systems
✔ explain the principles that govern organic farming.
Concept map
Agricultural science and agriculture
History of agriculture
in the Caribbean
Development
Pre-colonial
Colonial
Post-colonial
Conventional and non-conventional
crop and livestock farming systems
Aeroponics
Hydroponics
Grow boxes
Food security
Trough culture
Urban and periurban farming
Market gardens
Principles of organic farming
Soil management
Crop rotation
Green manure
Intercropping
Organic manure
and composts
Weed control
Pest control
IPM
Biological
Certification of
organic farms
1
Section A: Introduction to agriculture
1.1 The relationship between agriculture and
agricultural science
agriculture ▶
The word agriculture comes from the Latin agricultura, meaning ‘cultivation of
the field’. It covers all the arts, skills, sciences, industries and services used by
humans to obtain food from the land. This includes the cultivation of crops and
the rearing of livestock, together with the related industries that supply seeds,
chemical fertilisers, machinery, finance and technology. In addition, agriculture
involves marketing and processing.
ITQ 1
List as many different types of
agricultural production as you can,
focusing on those found in the
Caribbean.
‘Agriculture’ is often used to mean the same as ‘farming’ and ‘husbandry’. But
farming and husbandry have more to do with specific activities such as dairy
farming, crop husbandry, organic farming, livestock husbandry, mixed farming
and exotic farming.
Traditionally, agriculture has been recognised as the art of tilling the soil and as
a way of life for families in rural communities. With modern technology and
a rising world population, agriculture today is an applied science and business
focused on food production to ensure global food security.
1.2 The history of agriculture in the Caribbean
Development of agriculture in the region
Pre-colonial era
Agriculture in pre-colonial times involved mainly hunting and gathering. These
activities included hunting for wild boar and fishing. Root crops were the primary
crops planted. These crops included cassava, dasheen and sweet potato. During
the pre-colonial era, farming was managed through methods such as shifting
cultivation and slash and burn.
Colonial era
In the colonial era, the approach to farming changed drastically with the
introduction of crops such as sugar cane and banana. Some crops were introduced
to the Caribbean at this time, such as ackee and breadfruit. Slash and burn was
also practised in the colonial era as the main way to clear land, and livestock was
used to till the soil. Coastal fishing was popular around the islands and people used
simple boats and small fishing vessels to fish. Livestock rearing was introduced,
and consisted mainly of cattle (beef and dairy) along with an increasing reliance
on poultry for eggs and meat.
Post-colonial era
This era saw more changes in the technology used following the ‘green revolution’,
which encouraged the widespread use of synthetic fertilisers and pesticides to
increase crop production. It also saw the introduction of crop rotation to minimise
the negative impact of agriculture on the soil and water. Rearing poultry within
confined spaces for both eggs and meat grew rapidly to replace the dependence
on beef. The rearing of other animals, such as pigs for pork and bacon, and small
ruminants (goats and sheep) increased significantly. The diversification of crops
became more pronounced with the introduction of non-traditional crops such as
yam, banana, coffee, cocoa and coconut.
2
1: Agricultural science and agriculture
Food security
food security ▶
ITQ 2
Explain what is meant by ‘food
security’.
Practical activity:
Research a native Caribbean
species of plant or animal and
create a presentation on how it
is different from species found in
other countries.
Food security means being self-sufficient in nutritious, good-quality food. Most
Caribbean countries are now boosting their local food production and reducing
food imports.
In the Caribbean, food security is affected by:
• low agricultural productivity caused by the inefficient use of water and
other inputs
• a decline in earnings from traditional crops caused by the loss of trade
preferences
• a dependency on imported food caused by the inability to produce food locally
at competitive prices
• increased poverty in many countries caused by the loss of agricultural jobs.
1.3 Non-conventional and conventional
crop systems
Aeroponics
This is the process of growing plants in the air rather than in the soil. Plants are
usually grown suspended in the air in a greenhouse or other closed system. The
roots have no direct contact with water or soil. Nutrients and water are sprayed
onto the plant in a fine mist every few minutes. This method has advantages. The
plants tend to grow more quickly because the roots are exposed to oxygen. In
addition, the plants get all the nutrients they need and fewer nutrients are needed
because they are absorbed directly by the roots. However, specialist knowledge is
needed to achieve the correct mix of nutrients, and the equipment is expensive.
The root chambers also need to be kept clean as they are easily contaminated in
the warm, moist conditions.
Hydroponics
Figure 1.1 An A-frame hydroponics
system growing lettuce.
Practical activities:
1. Explain how you would grow a
salad crop using a grow box or
a trough. Include as much detail
about the necessary conditions
as possible.
2. Use a non-conventional method
to grow a crop, for example, a
grow box or trough culture.
Plants grown using a hydroponics system are grown in water. The water is full of
nutrients, which are taken up by the roots. Crops such as lettuce and tomatoes
are grown using hydroponics. This system has advantages. The plants receive the
nutrients they need, which speeds up their growth, and the process is totally
controlled by the grower. The plants can also be stacked to take up less space.
Strangely, the plants use less water than plants grown conventionally. Another
important advantage is that crops such as lettuce can be shipped in the water, prior
to being harvested, to increase their freshness. Soil contains a lot of diseases and
pathogens that can affect the crop. These diseases and pathogens are eliminated by
hydroponics. However, an important disadvantage is that the system is expensive
to establish and run.
Grow boxes
A grow box is used to grow plants in a self-contained environment. The box
has a hydroponics system, a built-in light and ventilation. Some grow boxes also
maintain the correct temperature and enrich the atmosphere with carbon dioxide
to boost growth. (Carbon dioxide makes plants grow more quickly.) Scientists use
grow boxes to grow plants in controlled conditions in laboratories.
3
Section A: Introduction to agriculture
Simplified grow boxes, suitable for patios and decking, have been created to grow
plants out of season, or for people who have no garden. Some grow boxes have a
watering system and deliver measured quantities of fertiliser, but they are designed
for outdoor use and do not include a lighting system or temperature control.
In the Caribbean, grow boxes of different sizes are constructed using local and
discarded materials, for example, bamboo, wood, galvanised sheets and bricks.
The growing medium used may be a mixture of topsoil, pen manure, sharp sand
and rotted bagasse (or plastering sand and rotted sawdust).
Trough culture
Trough culture involves growing crops in shallow troughs. Troughs can be filled
with an inert, soil-free medium such as rock wool and are connected to a drip
system that supplies water and nutrients in solution. Once the troughs have been
set up, they are easy and inexpensive to maintain. They can be used for vegetables
and flowers and the gardener can put them in greenhouses or anywhere
convenient.
Figure 1.2 Trough culture.
Both grow boxes and trough culture enable plants to be grown where space is
limited or the soil is poor. Modifications can be made to suit the circumstances, for
example, the number of units and their arrangement, the use of different types
of inert material and temperature and lighting control (if needed). Commercial
systems have many units, but both methods can be used on a smaller scale.
Urban and peri-urban farming
market gardens ▶
Urban and peri-urban farming is the cultivation of small areas of land, usually less
than two hectares, in or near cities, towns or villages. The small farms, or market
gardens as they are sometimes called, produce fresh vegetables, fruit and meat
for urban consumers. These benefit the community by increasing the quantity
and quality of the food available, contributing to food security.
Urban farms have many short-term crops that grow and ripen within three
months. Crops include tomatoes, lettuces, cucumbers, cabbages, pak-choi, celery,
sweet peppers and spinach. Sometimes four short-term crops are grown in a year,
so fertilisers are used to maintain soil fertility. If the small farm is mixed, with
some animals being kept as well, then farmyard manure is used together with
artificial fertilisers. This type of farming includes the use of pots, troughs, grow
boxes, hydroponics and sheds covered with polythene.
ITQ 3
Explain why it is more profitable
for a small farmer to sell his or her
produce directly to the consumer
(rather than sell it to a wholesaler).
Produce is harvested by the farmer, often with the help of his or her family,
who gets it ready for market. Vegetables are cleaned, graded and made to look
presentable to the consumer. If the farm is very small, the farmer will sell from a
roadside stall. If the farm is bigger, the farmer will sell to a wholesaler, who buys
the whole crop and transports it to a market where it is sold to retailers. Each time
produce is sold, for example, from farmer to wholesaler and from wholesaler to
retailer, the price increases.
Urban farms are important to the economy of the Caribbean region. Several
Caribbean governments have set up marketing boards to purchase crops from
urban farmers and retail the crops to the public.
4
1: Agricultural science and agriculture
The benefits of urban farms include:
• a reduction in transport costs, as food is grown locally
• fewer pesticides, which makes food production more sustainable
• no food preservatives as food does not have to travel long distances
• employment for local people.
1.4 The principles of organic farming
biodiversity ▶
ITQ 4
Why is crop rotation good for soil
fertility?
Organic farming restricts the use of herbicides and pesticides to increase
biodiversity. Biodiversity is the variety of living organisms in a specific habitat
or area. Organic farming benefits the environment in many ways. Different weed
species growing in an organic crop attract insects, which then feed on plant pests.
In turn, these insects provide food for birds and mammals. Farmyard manure is
used to add organic matter to the soil, which encourages soil micro-organisms
to break down the manure and increase the soil fertility. Overall, there are 30%
more species found on organic farms than on conventional farms.
Organically grown produce is usually more expensive than other produce because
of the increased time and labour required to grow crops organically. However,
people who care about the environment and who are concerned about pesticide
residues in food are often prepared to pay a higher price for produce.
Soil management on organic farms
soil management ▶
An organic farmer uses soil management to ensure a supply of the essential
nutrients (nitrogen, potassium and phosphorus). Instead of relying on artificial
fertilisers, the farmer can use some of the methods summarised in Table 1.1.
Method
Crop rotation
Description
• A sequence of different crops is grown from year to year
(cereals, root crops, legumes).
• The sequence is planned so that crops are grown on
different plots each year (see Figure 1.3).
Green manuring
• The ploughing in of a cover crop, for example, a legume.
• The ploughing in of a crop residue, for example, stubble.
• The crop is left on the surface of the soil and the next
crop is then planted through it by direct drilling.
• Two or more crops are grown at the same time on the
same land (see Figure 1.4).
• Crops may mature and be harvested at different times.
Intercropping
Use of organic manure and
composts such as crop
residues (sugar cane waste,
spent mushroom compost)
• Can be spread on the soil, ploughed in or used as a
mulch.
• Animal manure must be composted before use on the
soil, to kill pathogenic organisms.
Benefits to soil
• Life cycles of pests and pathogens are broken
(different types of crops attract different types of pests
and pathogens).
• Inclusion of a legume increases soil nitrogen.
• Different crops need different methods of cultivation so
this improves soil texture.
• Adds organic matter to the soil.
• Improves soil fertility by increasing soil nitrogen.
• Provides cover to prevent runoff during the wet season.
• A second crop can reduce competition from weeds.
• If a legume is included, this will encourage nitrogen
fixation.
• The cover of vegetation reduces runoff in the wet
season.
• Saves on space if more than one crop is grown on the
same piece of land.
• Adds organic matter, which binds soil particles together.
• Helps with aeration and drainage in clay soils.
• Helps retain water in sandy soils.
• Releases nutrients slowly over a long time.
(Artificial fertilisers release nutrients quickly.)
• Provides food for soil animals such as earthworms.
Table 1.1 Methods of managing soil fertility on organic farms.
5
Section A: Introduction to agriculture
Figure 1.3 A four-year crop rotation.
Figure 1.4 Intercropping: ackees and pasture.
Weed control on organic farms
weed control ▶
ITQ 5
How does intercropping benefit the
small farmer?
Integrated Pest Management (IPM) ▶
Organic farms do not use any chemicals, which can make weed control difficult.
Methods of weed control include hand-weeding, hoeing, mulching with compost,
and using plastic film spread across the ground. In rice-growing areas, ducks and
fish have been introduced to paddy fields to eat weeds and insects.
Pest control on organic farms
It is difficult to control insects and other pests without chemicals. Pests can
cause serious losses but organic farmers are not permitted to use any chemical
pesticides. If they do, their farms are not considered truly organic. Integrated
Pest Management (IPM) involves pest control using a range of complementary
approaches, including natural predators and other biological and environmental
control practices, instead of chemicals.
Crop nutrition on organic farms,
Caribbean Agricultural Research and
Development Institute (CARDI)
Organic farmers provide the required plant nutrients to their crops with the use of naturally produced materials
such as compost, animal manure, seed meal, ground bone, dried blood, fish meal and seaweed. These materials
slowly release their nutrients through the actions of the soil’s microbial processes, which is why soil health and soil
conservation programmes are key features of organic cropping systems. Some naturally occurring minerals are also
allowed. Like most production inputs, there are rules that must be followed with the use of organic compliant fertiliser
materials if organic certification is to be granted. With regards to crop nutrition, organic crop production standards have
restrictions that control the time of fertiliser application, the type of composting process used in compost production (aerobic
or hot composting is preferred), the type of crop that can be fertilised with specific materials, the origin of animal manure
and the amount of nutrients that can be applied to the soil within a particular time period. In terms of commercial fertiliser
formulations, the manufacturing process and the kinds of processing aids are also subject to regulation.
6
1: Agricultural science and agriculture
Biological control of screwworms
The Caribbean is home to the New World screwworm fly. This fly lays its eggs on the dry tissue surrounding livestock wounds.
Once the eggs are fertilised, larvae will develop. Larvae can grow up to 17 mm and have large mandibles for eating healthy
tissue. While these flies are found throughout the western hemisphere, the tropical climate of the Caribbean results in
common fly strikes and mass infections. However, it has been found that if the life cycle of an insect pest is interrupted, its
numbers will fall. The New World screwworm fly mates once and the female stores the sperm. If the sperm are defective,
fewer offspring will be produced. It is possible to sterilise male insects using ionising radiation (X-rays) and then
allow them to mate with normal females. The sperm will be defective and the eggs laid by the females will
not develop. This method has been an effective way to control screwworms in the USA and much of the
Caribbean, although Cuba, the Dominican Republic, Haiti, Jamaica and Trinidad and Tobago still have
a problem with the worms. Although uncommon, people can also be infected, though strict
personal hygiene can prevent this from becoming serious.
biological pest control ▶
ITQ 6
List FOUR ways to control weeds
without using a weedkiller
(herbicide).
Biological pest control involves the introduction of another species to control
the pest. The introduced species will reduce the population of the pest, but it will
not get rid of the pest completely.
The introduced species may be:
• a natural predator of the pest organism, such as a mite
• a parasitoid, such as a wasp that lays its eggs in another insect
• a parasite, such as a nematode worm that lives in slugs
• a pathogenic (disease-causing) organism, such as a bacterium.
ITQ 7
What are the drawbacks of biological
pest control?
Practical activities:
1. List insects that are useful to
farmers and crop growers.
Collect pictures of these insects
and, for each one, write a short
comment on its life cycle and
the way in which it benefits
agriculture. Create a poster using
the pictures and comments.
2. Choose a suitable piece of
ground or a container such as
a trough or a large pot, and fill
it with soil or compost. Plant
herb seedlings and grow them
without using any chemical
fertilisers or pesticides. Make
notes about what happens.
Before any biological control method is used, it has to be tested to make sure
that no unwanted diseases are introduced, that only the pest organism is affected
and that the control organism can be bred in sufficient numbers to be effective.
Biological control is most successful in greenhouse crops, for example, tomatoes
and cucumbers. The control organisms are introduced into the greenhouse (an
enclosed area), and the number of pests and predators can be carefully monitored.
Alternative control methods involve the use of chemicals and hormones to lure
insects to positions where they can be killed by other methods. Hormones from
female insects attract the males. If traps are baited with these hormones, the males
can be caught and destroyed. If there are no males available to mate with the
females, no eggs will be laid and the quantity of pests will be reduced over time.
Certification of organic farms
Farmers who want to sell their produce as ‘organic’ must first obtain certification.
At the moment, there is no organic certification in the Caribbean, so a farmer
who wants to be accredited as an organic farmer needs to decide which country
to use to obtain the certification. The organic awarding bodies of both the UK and
the USA are popular choices, but it makes sense for the farmer to select a country
that is connected in some way with the produce of the farm. For example, farmers
who export organic cocoa to the UK might obtain higher prices for their produce
if they obtain organic certification in the UK.
There are some basic steps to the certification procedure.
• The farmer finds a suitable agency that will carry out the procedure.
• The farmer makes an application (it is usually necessary to pay a fee at
this stage).
7
Section A: Introduction to agriculture
• The farm is inspected by the agency.
• The farmer is notified at a later date whether the application has
been successful.
The application form requires details about:
• soil fertility planning
• seeds and seed planting
• weed and pest management practices
• storage and handling of produce
• the crops grown and the fields used (a map of the farm has to be supplied)
• the plans for monitoring how the farm will be managed to avoid
contamination with non-organic products.
ITQ 8
List FOUR things that an inspector
will check on a visit to certify an
organic farm.
Practical activity:
Research herbal extracts used to
control pests and diseases, for
example, neem to control internal
parasites in animals, or aloe vera
used in poultry farming. Create a
table of the herbal extracts and
describe each plant, including
its scent.
8
When the farm is inspected, the fields, implements and buildings are reviewed.
The farmer provides the inspector with records of the crops planted, the sources
of seeds used, the harvesting and storage practices, the transportation methods
for the produce and the sales. Before a certificate can be granted, the land has to
be free from prohibited pesticides and fertilisers for three years. If livestock are
involved, the conditions in which they are kept, their feed and their medication
have to be inspected.
The inspectors have to be convinced that the producer uses techniques that
conserve and build soil resources, produce little pollution and support natural pest
management. In addition, the inspectors make sure that there is no contamination
from pesticides and fertilisers used on neighbouring farms.
Becoming ‘organic’ can be expensive and time-consuming for a small farmer.
There is usually a fee to be paid for inspection and certification, and a lot of recordkeeping and paperwork. However, the principles of organic farming encourage
the maintenance of ecological balance and biodiversity. Many consumers are
prepared to pay more for organically produced food.
1: Agricultural science and agriculture
Revision map
Urban and
peri-urban farming
uses land in and
near towns
and cities
Hydroponics —
growing crops
in water
Aeroponics —
growing crops
in air
Grow boxes
and trough
culture used
if space is
limited
Benefits
Crop
nutrients
provided in
solution
Crops are
easy to grow,
harvest and
clean
No harmful
chemicals
allowed
Maintains
ecological
balance and
biodiversity
Non-conventional
crop systems
Compost,
green manure
and crop rotation
used to maintain
soil fertility
Organic farming
Cultural
methods such
as hoeing
control weeds
Agricultural
science and
agriculture
Self-sufficient in
food production
with low reliance
on imports
For certification,
farm must pass
an inspection
Biological
controls
control pests
Food security
Poultry and pigs
reared in confined
spaces to
maximise output
History of
agriculture
Increases national
income and improves
nutrition
Root
crops
Synthetic
fertilisers and
pesticides used
to increase crop
production
Pre-colonial
agriculture
Colonial
agriculture
Slash and
burn
methods
Hunting and
gathering
Post-colonial
agriculture
Field crops such
as banana and
sugar cane
Cattle livestock
farming
(beef and dairy)
Poultry farming
(meat and eggs)
9
Section A: Introduction to agriculture
Examination-style questions
Multiple-choice questions
Write down the number of the question followed by the letter of the correct answer.
1. Which of the following is NOT a principle of organic farming?
A Use of compost
B Biological pest control
C Monoculture
D Protection of wildlife habitats
2. Crop rotation means:
A growing the same crop year after year
B growing crops in a different sequence each year
C planting two crops together at the same time
D sowing a cover crop after the main crop has been harvested.
3. A species of mite is used in biological pest control because:
A it lays its eggs in a pest insect
B it causes a disease in the pest
C it is a parasite of the pest
D it feeds on the pest.
4. In one form of pest control, male insects are sterilised to:
A make their sperm defective
B make them unattractive to the females
C attract the females to them
D kill their sperm.
Short-answer and essay-type questions
5. Describe how non-conventional farming methods differ from conventional farming methods.
6. (a) What is a peri-urban farm?
(b) Why is this type of farm beneficial to the community?
7. Describe the ways in which soil management can maintain soil fertility on an organic farm.
8. Describe the procedure by which a farm can become certified as an organic farm.
10
2
Section A: Introduction to agriculture
Role of
agriculture
and support
services
By the end of this unit you should be able to:
✔ discuss the importance of agriculture in national, regional and
international economies
✔ describe types of agricultural enterprises
✔ state the functions of the local, regional and international institutions.
Concept map
The importance of agriculture
Food security
Imported food compared
with locally produced food
Foreign exchange
Gross National Product
Employment
Land area in agriculture
National and regional policies
Trade liberalisation
Types of agricultural enterprises
Farming
Processing
Sales and marketing
Role of agriculture and support services
Institutions
Local
Ministries of agriculture
Regional
Caribbean Development Bank (CDB)
Caribbean Agricultural Research and Development
Institute (CARDI)
University of the West Indies (UWI)
College of Agriculture, Science and Education (CASE)
University of Trinidad and Tobago (UTT-ECIAF)
Guyana School of Agriculture (GSA)
International
Inter-American Institute for Cooperation on Agriculture (IICA)
The Food and Agriculture Organization (FAO)
The Inter-American Development Bank (IDB)
International Fund for Agriculture Development (IFAD)
World Food Programme (WFP)
Technical Centre for Agriculture and Rural Cooperation (CTA)
11
Section A: Introduction to agriculture
2.1 The importance of agriculture in national,
regional and international economies
Food security
food security ▶
Food security means being self-sufficient in food. Most Caribbean countries are
now boosting their local food production and reducing food imports.
Food security can be promoted by initiatives to improve food production and
marketing, expand trade opportunities, increase income and improve nutrition.
Impact of imported food compared with locally produced food
The agricultural sector can provide employment for many people. There is a wide
range of job opportunities, such as farming, agricultural education, marketing,
engineering and farm management. Improved agricultural production improves
the employment prospects of a region – if more food is grown locally then
more jobs are created. Importing food from abroad reduces the number of local
agricultural jobs and uses up valuable foreign exchange.
There is also concern about the quality of some of the food imported into the
Caribbean.
Foreign exchange earnings
Agriculture is very important to the economies of all Caribbean countries, both
regionally and internationally.
foreign exchange ▶
Foreign exchange is earned when Caribbean agricultural goods and services
are sold to other countries. For example, the export of bananas and coffee earns
foreign currency. However, when foreign agricultural goods and services are
imported, Caribbean currency is converted into foreign exchange. Importing
agricultural machinery from abroad is therefore a loss to the local community.
Contribution to Gross National Product
Gross National Product (GNP) ▶
The Gross National Product (GNP) is a measure of the current value of goods
and services from all sectors of the national economy. Agriculture is a vital sector
of the Caribbean national economy and contributes to the GNP.
Employment
The development of agricultural science means that a wide range of employment
opportunities have been created. Aside from farmers, there are numerous
positions associated with food production. Table 2.1 lists a few roles.
12
2: Role of agriculture and support services
Occupation
Job description
Labourers
• On farms, unskilled workers are involved in
• A basic knowledge of tools and machinery is useful
ploughing, planting and harvesting crops and looking
to gain employment.
after animals.
• An NVQ Level 1 qualification can be helpful.
Qualifications needed
Farmers
• Farmers cultivate their land, grow crops, raise
livestock and sell their produce.
• They liaise with advisors and are aware of new
developments and methods of production so
that they can make efficient use of the land and
resources.
• Farmers need a basic knowledge of agriculture, the
use of tools and machinery and should have the
ability to keep records and to control their finances.
• They need training to secondary level, studying to
NVQ Level 2 or CSEC level in agricultural science.
Overseers and managers
• Overseers and managers have responsibilities for
specific areas on large farms.
• They may do the same work as farmers, but will be
in charge of teams of labourers and may specialise
in crop production or raising animals.
• Overseers and managers need the same skills as
farmers, together with the ability to deal fairly with
the workforce (the labourers).
Extension officers
• Extension officers are advisors who inform farmers
about the latest developments in machinery,
equipment and farming techniques.
• They work with researchers to tell them what the
farmers need to be more productive.
• They provide a means of communication between
researchers and farmers.
• This job requires a diploma, associate degree or
bachelor’s degree in agriculture.
Research workers
• These include engineers developing new farm
• Usually a research worker will have a university
machinery, chemists developing new fertilisers and
degree in a science subject, for example, biology,
pesticides, and biologists researching new breeds of
chemistry, physics or engineering.
animals and new types of crop plants.
• Laboratory staff are trained to secondary level and
have good grades in Caribbean Examination Council
• Research is carried out in laboratories and institutes,
science subjects.
which employ other staff such as laboratory
technicians.
Veterinarians (vets)
• Vets care for sick animals and are also responsible
for testing animals for diseases.
• Veterinary nurses help the vets in their work.
• Vets need a university degree in veterinary medicine.
• Veterinary nurses need appropriate qualifications: at
least CSEC level in science subjects.
Agricultural engineers
• Agricultural engineers plan, supervise and manage
the building of agricultural projects including
drainage schemes, food processing plants and
structures for housing livestock.
• Many of the engineers work for government
agencies or are involved in research that works on
designing new agricultural equipment.
• This job requires a university degree in engineering.
Viticulturists
• These people are specialists in managing vineyards.
The job requires a knowledge of grapes, their
growing conditions, and when to harvest and prune.
• Viticulturists can also research new techniques for
culturing vines and breeding new varieties.
• Viticulturists need a basic knowledge of agriculture,
with specialist knowledge of grapes.
• Qualifications vary from a diploma to a university
degree in horticulture or an agricultural subject,
depending on level of responsibility.
Table 2.1 Job roles associated with food production.
13
Section A: Introduction to agriculture
A day in the life of an extension officer, Grenada
The day begins with the extension officer travelling from home or from the office to the farm. This may be a normal farm
visit or the extension officer will have an appointment. The extension officer will greet the farmer in a friendly manner.
“It’s a pleasure being on the farm; I can see that you cultivate many different crops. It seems that you are doing well.”
“Oh yes.”
“Do you have market arrangements for all the crops you produce?”
“Sure, I have arrangements with the hotels, supermarkets, MNIB* and I sell on the farm.”
“Do you have any major problems?”
“Not really, but I have some problems with insects eating my cabbages.”
The problem is identified and a recommended solution is given.
A total of four to six farmers are visited at different locations within a sub-district. The officer works with
the farmer to identify the different needs and problems and then recommends solutions to the farmer.
* Marketing and National Importing Board
Land area in agriculture
Practical activity:
Read the case study above and
answer the questions.
(a) Why is it important for the
extension officer to be friendly
towards the farmer?
(b) What solution might the
extension officer recommend
for this farmer’s problem?
Practical activity:
Select a career from the list in
Table 2.1 that you want to know
more about. Visit your local Ministry
of Agriculture’s offices to find out
more about this career. Complete
the research when you are back in
your classroom by investigating the
qualifications the career requires
and the employment opportunities
available in this career.
Throughout the Caribbean, there is a shortage of land available for agriculture, as
land is also needed for housing and for urban development such as roads, offices
and other infrastructure. Table 2.2 shows data from the World Bank describing
the percentage of land used for agriculture. The percentage change in land used
for agriculture in the 20-year period from 1996 to 2016 shows how much less
land is used for agriculture. It is most likely that where there has been a loss of
land for agriculture, this is because the land was used for urban development.
Where there has been an increase in agricultural land, this is probably the result
of policy changes, such as reducing reliance on imported food and deforestation
for timber.
Country
Jamaica
Antigua and Barbuda
The Bahamas
Barbados
Belize
Dominica
Dominican Republic
Haiti
Grenada
St Kitts and Nevis
St Lucia
St Vincent and the Grenadines
Trinidad and Tobago
Agricultural land in 1996 (%)
45.6
20.5
1.2
44.2
6.4
22.7
53.3
57.7
20.5
34.6
28.5
28.2
14.8
Table 2.2 Percentage of land used for agriculture.
Agricultural land in 2016 (%)
41.0
20.5
1.4
23.3
7.0
33.3
48.7
56.8
20.5
23.1
17.4
25.6
10.5
(Source: https://data.worldbank.org/)
National and regional plans for agricultural development
agricultural plans ▶
14
Agricultural plans are policy documents prepared by governments, private firms
or international organisations, which set out plans for agricultural development.
Normally, local or national plans are prepared by the government of each
Caribbean country for a five-year period. The plan for each country identifies
2: Role of agriculture and support services
the areas of agriculture that need attention and may specify the current status,
constraints, strategies and resources required for the development of each area.
Carefully prepared plans can result in agricultural development and national
development.
Regional plans for agricultural development are produced through the
cooperative efforts of Caribbean countries, based on the agricultural needs of the
region. Specific goals, objectives, constraints, strategies, resources and evaluation
procedures help to achieve the plans.
Trade liberalisation
trade liberalisation ▶
tariff ▶
Trade liberalisation helps global competitiveness. A fair trade in goods and
services develops when tariffs and non-tariff barriers are removed. A tariff is a
tax levied by a government on imports (or occasionally exports). A government
uses a tariff to protect a local industry or product to help its balance of payments
or to raise revenue.
The aim of global trade liberalisation initiatives is to encourage greater efficiency in
marketing and trade. The initiatives focus on restructuring trade policies to reduce
any barriers set up to protect producers and service providers from competition.
ITQ 1
How does importing food reduce the
number of job opportunities?
Practical activities:
1. Look at some regional, national
and international statistical
reports about food production,
imports or exports.
2. Using a computer, create graphs
to show food production in the
Caribbean, and compare this
region with other regions around
the world.
Trade liberalisation does not just depend on the removal of barriers and the
negotiation of better access to markets. It requires rules that control how each
government forms its trade policies. This should result in each country being
encouraged to improve productivity in agriculture and make greater efforts to
improve the quality of agricultural products.
2.2 Types of agricultural enterprises
Agricultural enterprises may be small and employ just the farmer (for example,
subsistence goat-rearing). Agricultural enterprises may be large and process the
primary products from a whole region into a product (for example, Blue Mountain
coffee in Jamaica).
Farming
Farming involves rearing livestock or growing crops. Farming also includes
horticultural techniques used to produce plants for sale. The products can be sold
directly to consumers at the market or to suppliers who will process and package
the goods into other products for resale locally or elsewhere.
Processing
Agro-processing involves turning agricultural produce into other products. For
example, fruit can be processed into products such as preserved fruit, jam, wine
and sauces, which can then be sold locally, nationally and internationally. Agroprocessing offers numerous employment opportunities. Workers range from
unskilled labour (in processing and packaging plants) to skilled biochemists and
quality assurance officers who have professional qualifications.
Sales and marketing
Agricultural produce is sold in shops and supermarkets and from market stalls. The
produce usually has to be transported from the farms to the wholesalers, and from
there to retailers and other outlets. Transportation involves loaders and drivers.
15
Section A: Introduction to agriculture
At the wholesalers, produce may be stored for some time, providing employment
for storekeepers, clerks and security officers. When the produce reaches the shops,
managers, cashiers and sales personnel are needed.
2.3 Institutions concerned with agricultural
development in the Caribbean
Local institutions
Local institutions, both governmental and non-governmental, are essential for
any modern agricultural economy. The quality of the support mechanisms has
an effect on the quality of the agricultural output. More importantly, it creates a
sound foundation for new initiatives, growth and expansion in the agricultural
sector.
Figure 2.1 Research stations are
important local institutions concerned with
agricultural development. They can carry
out livestock feed trials.
ITQ 2
What are the functions of the
Forestry Division of the Ministry
of Agriculture?
Each Ministry of Agriculture is divided into several divisions, which work in
collaboration with related agencies, farmers’ organisations and commercial
agribusinesses to provide support services to farmers and agriculturalists for
agricultural development.
In Trinidad and Tobago, the Ministry of Agriculture, Land and Marine Resources
was founded in 1839. It consists of 11 divisions (see Table 2.3). Each division
is responsible for different aspects of agriculture, planning and training. Some
ministries of agriculture undertake additional projects, such as when Barbados
hosted a Caribbean Community (CARICOM) ‘marketplace’ exhibition in 2018.
Regional institutions
ITQ 3
Describe the main functions of the
Caribbean Development Bank.
Caribbean Development Bank (CDB) ▶
Practical activity:
Visit your local regional
administration office and find out
how it helps the farmers in your
area. You could ask for advice
on irrigation schemes, or how to
prevent and control diseases in
crops grown locally.
If you are unable to visit the
administration office, use the
internet to make a comparison of
Ministry of Agriculture websites
and the information you can find on
their outreach activities.
16
There are many institutions in the Caribbean concerned with agricultural
development. Some provide advice and support, while others provide specialised
training for careers in the agricultural sector.
The Caribbean Development Bank
The Caribbean Development Bank (CDB) assists Caribbean nations in
financing projects for its members. Its purpose is to contribute to the economic
growth and development of member countries and to promote economic
cooperation and integration.
Its main functions are to:
• assist members in the coordination of their development programmes with a
view to achieving better utilisation of their resources, making their economies
more complementary, and promoting the orderly expansion of their
international trade
• mobilise additional financial resources for the development of the region
• finance projects and programmes contributing to the development of
the region
• provide technical assistance to regional members
• promote private and public investment in development projects
• stimulate and encourage the development of capital markets within
the region.
2: Role of agriculture and support services
Name of division
Functions
Planning Division
• Identify goals and objectives.
• Determine the ministry’s vision and mission.
• Formulate plans and policies.
• Collaborate with other ministries and agricultural organisations.
• Identify major agricultural projects.
• Determine the order of priority and cost projects.
• Implement agricultural projects systematically.
• Coordinate the implementation process and keep records.
• Provide advice and information on agricultural state lands.
• Handle lease assignments and transfers.
• Collaborate with the lands and surveys department.
• Monitor the terms and conditions of leased lands through visits and record-keeping.
• Repossess and re-advertise state lands for lease.
• Conduct laboratory tests and analysis of soils, pests, diseases and livestock feeds.
• Provide technical advice, information and solutions relating to farming problems.
• Conduct trials on improved crop varieties and exotic farm animals.
• Issue import permits and quarantine plants and animals for observation, treatment and certification.
• Provide advice and information on agricultural machinery and equipment.
• Advise farmers on designs of farm ponds, livestock buildings, irrigation and drainage projects, and access roads.
• Propagate and sell planting materials (plants, seeds, cuttings, tubers, rhizomes) to farmers.
• Cultivate and sell farm produce: wet cocoa beans, bananas, citrus, mangoes, avocados.
• Produce and sell honey, queen bees and starter colonies.
• Propagate and sell forest plants (teak, Caribbean pine, mahogany, cedar) to farmers.
• Manage forest reserves, parks, forested recreational areas and wildlife.
• Maintain demonstration areas of agro-forestry and silviculture.
• Undertake reafforestation of watersheds and deforested areas.
• Issue permits for hunting and keep records of animals caught.
• Provide technical advice and information to farmers on forestry establishment and management.
• Sell forest trees to sawmillers and supervise harvesting operations.
• Conduct registration of fishermen and -women and aquaculturalists.
• Process applications for the importation, registration and transfer of commercial fishing vessels and engines.
• Issue permits for the import / export of fish (ornamental and food) and seafood.
• Provide technical advice, assistance, information and training courses for fishermen and -women and aquaculturalists.
• Organise and conduct technical training on a wide range of agricultural courses at the Farmers’ Training Centre, Centeno.
• Provide technical advice and information to farmers.
• Publish and supply technical information bulletins and factsheets on crops and livestock.
• Conduct extension training at all agricultural county offices.
• Provide surveillance of livestock farms for the diagnosis, treatment, prevention and control of animal diseases.
• Conduct laboratory tests and post-mortem examinations (necropsy) of farm animals.
• Control vampire bats against the transmission of paralytic rabies in livestock.
• Develop and implement preventive medicine programmes for animals.
• Provide technical advice, information and artificial insemination of cattle.
• Produce and sell farm animals, goats, cattle (culled, injured) to interested persons.
• Process applications for farmers’ identification and agricultural incentives at agricultural county offices.
• Provide advice, information and assistance on access roads and designs of farm ponds, irrigation, drainage and
livestock buildings.
• Monitor and control destructive agricultural pests and diseases.
• Provide technical assistance in managing apiaries and bee abatement (nuisance, swarms).
• Sell seeds produced locally at Chaguaramas, Trinidad.
Project Implementation
Unit
Land Administration
Division
Research Division
Agricultural Engineering
Division
Agricultural Services
Division
Forestry Division
Fisheries Division
Extension, Training and
Information Division
Animal Production and
Health Division
Regional Administration
Divisions (North / South)
Table 2.3 The functions of the divisions of the Ministry of Agriculture, Land and Marine Resources, Trinidad and Tobago.
17
Section A: Introduction to agriculture
Caribbean Agricultural Research and ▶
Development Institute (CARDI)
The Caribbean Agricultural Research and Development Institute
The Caribbean Agricultural Research and Development Institute (CARDI)
conducts research and demonstrates appropriate technologies to farmers.
CARDI provides technical assistance in areas such as:
• crop production, integrated pest management (IPM) and farming systems
• livestock and forages
• environmental and soil management
• technology services, for example, the supply of quality plant products and
genetic products and services
• market research and statistical services
• business development and consultancy.
Figure 2.2 The Caribbean Agricultural Research and
Development Institute’s (CARDI) research station is breeding
fruit trees with traits that discourage insect predators.
University of the West Indies (UWI) ▶
College of Agriculture, ▶
Science and Education (CASE)
Practical activity:
Imagine that you are an
entrepreneur who wishes to
establish a forestry business.
Explain which institutions you
would need to consult to finance
your business and find suitably
qualified staff.
18
Figure 2.3 Genetic characteristics are used to manage pests.
The mango project grafts sweet mangos onto sour mango
plants to prevent pest attack in the early stages of growth.
The University of the West Indies
The Faculty of Science and Agriculture at the University of the West Indies
(UWI) offers a wide range of courses leading to qualifications, from diplomas to
post-graduate degrees. Qualifications can be obtained in natural sciences such as
life sciences and chemistry, and in aspects of agriculture, such as animal science,
food production, economics and extension services. In addition, research units
investigate specific problems related to crop and livestock production.
The College of Agriculture, Science and Education
The College of Agriculture, Science and Education (CASE) in Jamaica is
a multi-disciplinary tertiary-level educational institution that offers diplomas,
associate degrees and bachelor degrees. Of particular relevance are its bachelor
degree courses in business studies, environmental science and agri-production
and food systems management. There are associate degree courses in general
agriculture, agricultural education, natural science and business studies. There
are also courses leading to diplomas in agriculture and teaching qualifications.
The Department of Animal Science helps to increase productivity of livestock, and the
Department of Plant, Soil Sciences and Engineering provides training in agronomy,
plant science, soil science, horticulture, land surveying, plant protection and crop
production. The Diploma in Agriculture was designed to train skilled practitioners
in specific areas of agriculture, who would put their training into practice on farms
and in other agricultural enterprises. An Associate of Science degree trains students
to be highly competent farmers and ‘agri-preneurs’. This qualification enables
graduates to enter most jobs that require a knowledge of agriculture.
2: Role of agriculture and support services
University of Trinidad and Tobago Eastern ▶
Caribbean Institute of Agriculture
and Forestry (UTT-ECIAF)
Guyana School of Agriculture (GSA) ▶
ITQ 4
What is the role of the University
of the West Indies in agricultural
development in the Caribbean?
The University of Trinidad and Tobago
The University of Trinidad and Tobago Eastern Caribbean Institute of
Agriculture and Forestry (UTT-ECIAF) offers diploma courses in agriculture
and forestry education. Students from ECIAF can gain employment in agriculture
or enter other higher education courses if they wish to. There is a strong business
focus at ECIAF and students are supported with entrepreneurship.
The Guyana School of Agriculture
The Guyana School of Agriculture (GSA) provides training to certificate
and diploma level in agriculture. The one-year certificate course trains students
to become forestry technicians and teaches them the principles of sustainable
forestry. A two-year diploma course equips young people for careers in farming.
The diploma courses lead to careers as agricultural science teachers or agricultural
field assistants. These courses are in agriculture, animal health, veterinary public
health and livestock production and management.
International institutions
The Caribbean nations are part of the global economy. Agricultural development
therefore depends on international institutions as well as local and regional
organisations.
Inter-American Institute for ▶
Cooperation on Agriculture (IICA)
The Inter-American Institute for Cooperation on Agriculture
The Inter-American Institute for Cooperation on Agriculture (IICA) is an
institution for agricultural research and graduate training in tropical agriculture.
It was founded in response to changing needs in the Americas and it has evolved
into an agency for technical cooperation in the field of agriculture, promoting
agricultural development and rural well-being.
The IICA supports and encourages:
• agro-energy and bio-fuels
• biotechnology and bio-safety
• rural communities
• trade and agribusiness
• trade negotiations
• institutional modernisation
• technology and innovation
• environmental management
• agricultural health
• organic agriculture.
Food and Agriculture Organization (FAO) ▶
The Food and Agriculture Organization
The Food and Agriculture Organization (FAO) of the United Nations leads
international efforts to defeat hunger. It helps countries to modernise and improve
agriculture, forestry and fishery practices and to ensure good nutrition for all.
Within the organisation, there are departments for:
• agriculture and consumer protection
• economic and social development
• fisheries and aquaculture
• forestry
• natural resources management and environment
• technical cooperation.
19
Section A: Introduction to agriculture
ITQ 5
Explain why the Food and Agriculture
Organization is important.
Inter-American Development Bank (IDB) ▶
There are regional, sub-regional, country and liaison offices worldwide. There is
a sub-regional office for the Caribbean in Barbados and country offices in many
Caribbean countries.
The Inter-American Development Bank
The Inter-American Development Bank (IDB) is an international
organisation established to support Latin American and Caribbean economic and
social development and regional integration. It is the largest multilateral source
of financing and lends money mainly to governments and government agencies.
The bank is owned by 47 member states of which 26, including the Caribbean
countries, can borrow money and 21 cannot. There are some criticisms of the way
in which it works. Some of the projects are considered to be damaging to local
environments and local people.
International Fund for Agriculture Development
The International Fund for Agriculture Development (IFAD) works directly
with the world’s poorest people living in some of the most remote regions of the
world. They fund cost-effective and people-centred programmes to help small
family farmers invest in business. They pay particular attention to disenfranchised
people, that is, women, youth and indigenous people. IFAD contributes to project
design and invests time and money in projects that lead to higher production,
better incomes for rural people and improved nutrition and life opportunities.
IFAD also helps rural communities become resilient to climate change.
IFAD supports rural people in business projects and assists them in understanding
what is needed for these to succeed: secure land tenure; access to markets,
capital and knowledge; clean water, reliable roads and transportation; tools and
technology and seeds and fertiliser. The focus for IFAD is not simply on cash
injections.
ITQ 6
How does IFAD work with people in
the rural Caribbean?
Examples of IFAD work in rural Caribbean areas include helping:
• young people become entrepreneurs
• farmers understand and access markets
• indigenous people manage irrigation systems more effectively.
World Food Programme
The World Food Programme (WFP) assists 91.4 million people in 83 countries
each year. It is the leading humanitarian organisation delivering food assistance
in emergencies and working with communities to improve nutrition and build
resilience. The international community has committed to end hunger, achieve
food security and improved nutrition by 2030, but one in nine people worldwide
still does not have enough to eat. Food and food-related assistance are key to
breaking the cycle of hunger and poverty.
In emergencies, WFP is often first on the scene, providing food assistance to
the victims of war, civil conflict, drought, floods, earthquakes, hurricanes,
crop failures and natural disasters. When the emergency subsides, WFP helps
communities rebuild their lives and also works to strengthen the resilience of
people and communities affected by protracted crises, such as areas affected by
eruptions in Montserrat.
20
2: Role of agriculture and support services
WFP purchases three million metric tons of food every year. At least 75% of this
comes from developing countries. By buying food as close as possible to where
it is needed, WFP can save time and money on transport costs, and help sustain
local economies. Increasingly, WFP meets people’s food needs through cash-based
transfers that allow the people to choose and shop for their own food locally.
Practical activity:
Choose one of the international
institutions and use the internet
to find out more about its impact
on agricultural development in the
Caribbean. Design a poster that
could be displayed in the local
agricultural county office informing
farmers of the functions of the
institution and how it affects them.
ITQ 7
What are the goals of the CTA
in African, Caribbean and Pacific
countries?
Technical Centre for Agriculture and Rural Cooperation
The Technical Centre for Agriculture and Rural Cooperation (CTA) believes
that investment in the right innovations in agriculture will help to catalyse
development. Youth, digitalisation and climate resilience are CTA’s priority
intervention areas in its strategic plan, 2018–2020, which are critical to driving
progress towards the United Nations Sustainable Development Goals.
African, Caribbean and Pacific (ACP) countries have identified youth employment
as a key determinant factor for sustainable development. An empowered workforce
starts with the engagement of youth and youth organisations. CTA offers young
entrepreneurs a step up to becoming the next generation agribusiness leaders
driving change in the agricultural revolution from a local position. Many of these
‘agri-preneurs’ bring ICT solutions to age-old problems. In the digitalisation of
agriculture, smallholder farmers are being offered new ways to improve their
livelihoods. The implications for productivity, reduction of food waste and even
gender equity are enormous. Digitalisation is also at the heart of climate-smart
agriculture. Many solutions that can help agricultural systems to adapt and
mitigate the effects of climate change have emerged. The challenge is in the
delivery of these solutions to farmers that need them the most, which CTA is
committed to doing.
21
Section A: Introduction to agriculture
Revision map
Gross
National
Product
(GNP)
Foreign
exchange
earnings
Agriculture is a
key sector of the
Caribbean
economy
Local food
production
provides
employment
Planning
results in agricultural
development and
boosts national
and regional
economies
Agricultural
productivity
Fair trade
for goods and
services
Greater
marketing
efficiency
Global trade
liberalisation
Role of
agriculture
Role of
agriculture
and support
services
Careers in the
agricultural
sector
Skilled
employment
Institutions
Unskilled
employment
Produce
marketing
22
Food
production
The agricultural
development of Caribbean
countries depends
on contributions from
international
organisations
Ministries of
agriculture and other
agencies and institutions,
provide agricultural
support services
Some institutions
provide specialised
careers training
2: Role of agriculture and support services
Examination-style questions
Multiple-choice questions
Write down the number of the question followed by the letter of the correct answer.
1. An example of agro-processing is:
A the manufacture of new fertilisers
B producing jam from fruit
C ploughing the land
D the butchering of domestic livestock.
2. Trade liberalisation means that:
A fair trade in goods and services is encouraged
B market access is restricted
C local farmers produce fewer crops
D more people are buying locally produced crops.
3. The movement of goods and services from the agricultural producer to the consumer is:
A transportation
B marketing
C export
D management.
Short-answer and essay-type questions
4. Explain how foreign exchange can be earned from agriculture in the Caribbean.
5. Outline the work of the Animal Production and Health Division of the Ministry of Agriculture.
6. What are the functions of the World Food Programme?
7. Describe how regional agricultural projects are funded.
23
Section A: Introduction to agriculture
3
Challenges in
agriculture
By the end of this unit you should be able to:
✔ discuss the major challenges affecting local and regional agriculture
✔ discuss possible solutions to the major challenges affecting agriculture in
the Caribbean.
Concept map
Challenges in agriculture
Major challenges
Climate
Topography
Rural infrastructure
Access to finance
Praedial larceny
Land tenure systems
Loss of agricultural land
Environmental degradation
Atmospheric
Water
Land
Global warming
Coral reef destruction
Deforestation
Availability of labour
Ageing farming population
Limited participation of youth
Food safety
Natural disasters
24
Possible solutions
Climate
Windbreaks
Organic mulches
Topography
Contouring and terracing
Rural support
Extension services
Access to finance
Loans from banks, cooperatives and credit unions
Praedial larceny
Proof of purchase
Higher security
Higher fines for offenders
Raising public awareness
Land management
Sharecropping arrangements
GIS to map land quality
Sustainable land use
Availability of labour
Encourage young people into farming
Increase technology use in rural areas
Food safety
Restrictions in animal movement
Encourage biosecurity
Natural disasters
Comprehensive disaster management
Strengthen infrastructure
Invest in rural infrastructure
3: Challenges in agriculture
3.1 Local and regional challenges
The major challenge confronting agriculture is food security. This is the continuing
ability to feed an ever-increasing global population while protecting the natural
environment from degradation. Improved methods of crop production and
livestock husbandry can result in higher yields, but these yields have to be
balanced against the effect they have on the environment. In this unit, local and
regional issues are considered, together with worldwide challenges such as global
warming and maintaining biodiversity.
ITQ 1
Describe THREE ways in which
crops can be protected from
powerful storms.
climatic conditions ▶
In the Caribbean, agriculture is an important part of the economy and a major
employer, particularly in rural districts. Traditional methods of agriculture
are labour-intensive and time-consuming. Increasing the use of machinery in
agriculture will result in more skilled workers, better-paid jobs and higher yields,
which will improve the contribution to the GNP from agricultural businesses. In
this unit, we also consider some issues that affect the progress of agriculture across
the Caribbean.
Climate
Agricultural production is directly affected by climatic conditions. For any
period, production may be high or low depending on the weather conditions. The
Caribbean has two distinct seasons: a dry season and a wet season, although the
months comprising the two seasonal periods vary slightly across the territories.
In the dry season, there is plenty of sunshine and the temperatures are high, but
there is a shortage of water, especially for crop irrigation. Areas with no water
cannot produce crops during this time, unless the farmers use climate-smart
techniques, for example, growing cassava, a crop that needs little water. The wet
season has heavy rainfall, cool temperatures, high humidity and strong winds.
Hurricanes are common during the wet season, and the associated floods and
strong winds can damage crops and livestock. Other challenges to cultivation
include pests and diseases, which are more common during the rainy season.
Figure 3.1 Example of a windbreak.
Figure 3.2 Example of organic mulch
in use.
topography ▶
Strategies for coping with climate
• In the dry season, farmers conserve soil water using cultural practices such
as organic mulching, including organic matter and manure in the soil and
transplanting seedlings into concave ‘pockets’ to keep soil water within the
root zone.
• In the rainy season, drainage systems are essential. Farmers use cambered
beds and ridges for crop cultivation, and prune and stake crops.
• Governments can give farmers subsidies to establish ponds, which will reduce
the disastrous effects of flooding and allow farmers to store water for the dry
season. This practice needs to be carefully monitored, however, as ponds can
result in excessive numbers of mosquitoes.
• The Forestry Division, another part of the government, can help farmers to
establish windbreaks in areas where crops suffer from strong winds.
Topography
Topography is the physical shape of an area. Farmers prefer to cultivate land
that is flat because it is easier to move machinery and equipment across it for land
preparation, crop harvesting and transportation of produce. However, most of
the Caribbean is hilly or mountainous, so farmers have no alternative but to use
manual methods for most field operations.
25
Section A: Introduction to agriculture
ITQ 2
Explain why the mechanisation of
farming in the Caribbean is limited.
Mountainous areas have shallow topsoil and are prone to soil erosion and
landslides. Farmers can carry out strip cropping, cover cropping, contouring and
terracing (see Unit 5). Erecting barriers of stone, wood or grass can help to control
soil erosion, but this process is expensive.
Figure 3.3 Hilly terrain makes it difficult to use machines.
Practical activity:
Visit a local farm and list all the
machinery available and in use.
Make another list of jobs that could
be done more efficiently if the
farmer could purchase a machine to
perform the task.
Mechanisation in hilly areas
Mechanisation allows farmers to complete agricultural tasks more speedily and
efficiently. This increases the production and profitability of farms. However,
in the Caribbean there is limited use of machinery because of the steep slopes.
The use of machinery has improved in areas where the terrain permits it. This is
particularly true in the sugar cane industry in Jamaica and Trinidad.
Some machinery is used for preparing land, milking cows, plucking chickens,
applying pesticides, controlling weeds and irrigating crops throughout the
Caribbean. More mechanisation needs to be developed for use in the Caribbean,
specifically in hilly terrain, and be reasonably priced for farmers. The governments
of Jamaica and Grenada provide tractors and implements to small farmers at a
minimal cost for lease or hire.
Rural infrastructure
infrastructure ▶
ITQ 3
What basic facilities does a rural
community need to provide a
satisfactory lifestyle for farmers
and their families?
rural-to-urban drift ▶
26
In the Caribbean, some rural communities develop from a collection of farms. In
some areas, infrastructure such as transport, communication systems, water
supplies, power lines, schools and medical facilities are developed to help farming
communities. However, many rural areas still lack essential infrastructure. There
is often no incentive for farmers to continue living in these areas because of the
difficulties they face without amenities. Many rural areas also lack shops and
public transport systems.
Farmers want their families to have a good quality of life, and their children
often enter different careers. As the children of farmers migrate to urban areas,
this rural-to-urban drift (where the rural population migrates to more urban
areas for employment) causes abandonment of agricultural land, absentee
farmers, a shortage of agricultural labour and a reduction in agricultural
production. Investment in rural infrastructure is the only way to increase
agricultural production and food security. This investment needs to come from
the governments of Caribbean countries, and should include more incentives for
young people to take up farming, and better access to extension services to help
reduce rural-to-urban drift.
3: Challenges in agriculture
Extension services
Practical activity:
Research the Agro Parks Programme
of the Ministry of Agriculture. Does
your country have agro parks?
The Caribbean has a pool of technical knowledge about agriculture, gained
from developments in science from around the world, but applied to Caribbean
territories. A number of regional territories have websites where farmers can
access technical agricultural information. Throughout the Caribbean, extension
officers make farmers aware of the latest developments in agriculture and
encourage them to adopt appropriate technology.
ITQ 4
Why are the extension officers
important to farmers?
ITQ 5
Why are farmers reluctant to use new
technical knowledge? How can this
problem be resolved?
Access to finance
If a farmer needs to finance an agricultural enterprise and has no family money,
he or she may look for a low-interest loan. The farmer may have to offer capital
assets as collateral to the bank or lender. Collateral is property that you agree to
give to a bank if you fail to pay back money that you have borrowed. Having
capital helps to make the farmer self-reliant. Farmers with larger farms will find
it easier to borrow money because larger farms have many assets, which means
that larger farms will have greater profits and the farmers will
repay their loans more quickly. Loans can be obtained from
commercial banks, agricultural banks, cooperatives, credit
unions and micro-financing organisations.
Commercial banks
Some commercial banks have agricultural advisors who
understand farming problems and can give advice. However,
these banks make loans only to large farms. Commercial banks
do not judge small farmers as a good risk because small farmers
may not be able to repay a loan promptly if their profits are
affected by a bad harvest, hurricane or other disaster. The
Caribbean Development Bank is committed to financing
projects in the region and has departments that lend money
with long-term repayment plans to farmers.
Figure 3.4 Rural infrastructure.
Cooperatives
A cooperative is a group of several farmers who work together to apply for a loan.
Banks tend to look more favourably at these applications.
Credit union
A credit union is a cooperative financial institution that is owned and controlled
by its members, which makes it different from a conventional bank. Credit unions
offer savings accounts and usually lend money at lower rates of interest than
commercial banks.
Extension services – demonstrations
Farmers in a local farmers’ cooperative who supply vegetables and condiments to greengrocers,
hotels and agro-processing factories were severely affected by the beet armyworm (BAW). A team
from the Plant Protection Division and extension officers from the Ministry of Agriculture established a
demonstration plot to expose farmers to field practices such as field sanitation, scouting for eggs and larvae,
nutrition and water management. After one crop cycle, the farmers observed from the demonstration plot an
increase in overall production as well as a reduction in pest infestation.
27
Section A: Introduction to agriculture
Praedial larceny
praedial larceny ▶
Praedial larceny is the stealing of agricultural produce, such as crops and
livestock, which causes severe economic loss to farmers. This crime deprives
farmers of the opportunity to harvest what they have planted and nurtured. It
is mainly a problem for farmers who cultivate crops that are easy to harvest, for
example, bananas, watermelons, pumpkins, cabbages, corn and cucumbers.
Security measures range from placing shells on the soil at the foot of trees to alert
the farmer to a burglar to using dogs, lighting and fencing. Many farmers use
family members to guard the land at night, especially close to harvest. Countries
throughout the Caribbean have different police initiatives to help prevent praedial
larceny. In Grenada, for example, there is a Police Farm Watch programme. In
Jamaica, some of the strategies that the government and agricultural society
have put in place are fines, a praedial larceny unit in the Jamaica Police Force
and a receipt system. In the receipt system, if a person is caught transporting
agricultural produce without a receipt, the person will be arrested, charged and
prosecuted. However, the culprits are not always caught. It may be difficult to
identify offenders and bring them to justice. The few people who have been
caught in the act have had low fines imposed by the courts. As a result, some
farmers, especially those targeted regularly, have given up commercial farming.
ITQ 6
Suggest THREE ways in which
praedial larceny can be reduced.
Regional governments need to address the problem with strategies such as:
• vendors showing proof of purchase
• hiring security for estates or encouraging farmers’ cooperatives to hire
security officers
• ensuring a higher police presence in rural districts
• imposing more severe fines on offenders
• raising public awareness of praedial larceny and the impact it has on farmers
and local food production.
Land tenure systems
land tenure ▶
Land tenure refers to the rights and conditions under which people hold, own,
use and control property (land). For the farmer, land is necessary for agricultural
production and is a vital resource. Traditionally, parents have handed down land
as a legacy to their children. With each generation, subdivision of the land has
resulted in fragmentation (see Figure 3.5). These smaller units are often too small
to be run as economically viable farms.
large parcel of land
smaller parcel
smaller parcel
non-economically viable farming units
Figure 3.5 Land fragmentation occurs when land, handed down through generations,
is subdivided.
tenant farmers ▶
28
Some landowners are not interested in farming the land themselves. They allow
farmers to rent the land or enter into a share-cropping arrangement. The farmers
who rent the land are known as tenant farmers. As the land is not their own,
the farmers can be evicted so tenant farmers do not always work on improving
the soil or manage the land sustainably.
3: Challenges in agriculture
Small ruminant farmer, Jamaica
Farmer Joan is a small ruminant farmer who grazes her animals on pastures adjacent to the banks of the Rio
Minho. One afternoon, she went to the pasture to check on her animals and realised that 10 of her Nubian
goats were missing. She immediately alerted the police (Praedial Larceny Prevention Unit) who issued an
immediate bulletin. The goats were recovered in the back of a truck with two men aboard.
The men were arrested and charged under the Praedial Larceny Act and were later sentenced to
five years in prison with hard labour.
Loss of agricultural land
In the Caribbean, land is a symbol of economic power. Land often rises in value
over time and may be used for housing or business, provided that approval is
granted by the government. However, land is scarce on islands and needs to be
used carefully. Governments need to reform policies for state lands and areas that
have been abandoned by their owners. Each Caribbean state needs to ensure that
agricultural lands are identified and allocated by a land tenure system to farmers
for agricultural production and national food security. In some countries, tougher
measures are needed to ensure that good agricultural land is not used for the
development of residential areas.
Geographical Information Systems (GIS) can be used to map the quality of
agricultural land with settlement infrastructure to prevent conflict on islands that
have a high population. For example, in Jamaica, agricultural land that was once
used for the cultivation of sugar cane and tobacco is now used for the construction
of housing and urban infrastructure.
Initiatives to combat praedial larceny,
St Lucia
St Lucia once had a thriving agricultural economy. However, over the years there has been
a drastic decline in the industry, resulting in less produce and higher prices. A number
of factors have been identified as contributing to the decline, one of which is praedial
larceny. Praedial larceny is defined as the theft of agricultural produce. This has been an
issue for many years, but the escalating frequency and scale has farmers, especially small
farmers, abandoning the land.
Figure 3.6
Produce that is not
Many initiatives have been put in place but the problem persists, due mainly to the lack
guarded well can make a farm an
of resources. A praedial larceny unit has been established in the agriculture ministry, but
easy target for theft.
it lacks the necessary manpower to investigate reported cases. In addition, cases that are
prosecuted take a long time to be heard. This results in many cases eventually being dropped. Many farmers have resorted
to settling out of court. It is also believed that in most cases that are tried, the offenders get off lightly. The crime carries
a maximum of two years’ imprisonment and / or fines of US$ 20 000. Many offenders who are found guilty end up paying
US$ 250 or less or serve as little as three months in jail. These types of penalties give offenders a feeling that the fine is
‘nothing’ to pay, and many continue to steal.
It is believed that lectures, town hall meetings, night courts to expedite these cases, the establishment of pounds to hold
animals and the issuing of identification cards to farmers will go a long way towards curbing the problem.
29
Section A: Introduction to agriculture
Sustainable land use
More sustainable management of land can reverse land degradation and
desertification. But management of land resources needs to be improved if it is
to address the following problems: loss of soil fertility, reduction in freshwater
resources, loss of biological diversity and degradation of coastal ecosystems.
sustainable land use ▶
ITQ 7
Describe how Jamaica manages
land sustainably.
Sustainable land use is a term that means planning and managing land for
agriculture, settlement development, tourism, forestry and livestock. To increase
sustainable land use within the region, a partnership of national, regional and
international organisations with farming and forestry communities has been
proposed. The partnership will look at integrated land use management, food
security, appropriate technologies, economic development and environmental
protection. Sustainable land use is currently practised within the protected areas
of Jamaica, for example, Cockpit Country, Blue Mountains and John Crow
Mountains. Integrated land use management integrates long-term planting
of trees (mahoe and oak) with short- to medium-term crop rotations (such as
pineapple).
Environmental issues
Practical activity:
Have a look at the rivers in your
local area. Look particularly at the
growth and extent of the water
plants. Do you think that nutrients
are washing off farmland into
the rivers?
environmental degradation ▶
atmospheric pollution ▶
water pollution ▶
ITQ 8
What are the consequences of
sewage leaking into fresh water?
30
Farmers interact with the natural environment by removing vegetation, tilling the
soil, introducing new plant species, spraying crops with pesticides and modifying
micro-climatic conditions. Although these farming practices are necessary for food
production, environmentalists worry about the harmful effects of these practices.
The major concerns about the effect agriculture can have on the environment are:
• the destruction of ecosystems
• the loss of biodiversity
• the threat of air, land and water pollution
• the pests becoming resistant to pesticides.
Environmental degradation refers to the environment being damaged in some
way. Environmental degradation is brought about by the following factors.
Atmospheric pollution
Pollution occurs when the environment is contaminated by toxic substances.
Atmospheric pollution is pollution of the air. It is caused mainly by burning
fossil fuels, often to generate electricity. Smoke, dust particles and gases (carbon
dioxide, sulphur dioxide, nitrogen) are released. Sulphur dioxide is poisonous
and dissolves in rainwater to form acid rain, which damages crops. An increase in
carbon dioxide contributes to global warming. Atmospheric pollution is difficult
to control, other than by reducing dependence on fossil fuels and reducing carbon
footprints.
Water pollution
Water pollution describes toxic substances getting into streams, rivers and
oceans. Some of these substances come from pollutants in the atmosphere. Others
result from sewage, excessive use of fertilisers and pesticide runoff. Organic matter
and nutrients in fresh water can cause algae to grow rapidly and crowd out other
water plants. When the algae die, they are broken down by bacteria, and the
process uses up oxygen in the water. The result is that other aquatic organisms
die through lack of oxygen (eutrophication). In marine ecosystems, agricultural
runoff can upset the food webs. Oil spillage kills seabirds and affects plankton,
which marine organisms are dependent upon for food.
3: Challenges in agriculture
Eutrophication on the
Rio Cobre, Jamaica
On the Rio Cobre in Jamaica there is a problem with
eutrophication. Excess nutrients from fertilisers, cattle faeces or
human sewage that enter the river have resulted in a build-up
of water hyacinth in the channel. This is being cleared regularly
by the government, but the water hyacinth still build up at
certain times of the year, blocking the river.
Figure 3.7 shows the coverage of water hyacinth approximately
six months after the channel was fully cleared of plants.
Figure 3.7
land pollution ▶
Land pollution
Land pollution can be caused by agricultural activities, urban waste disposal
and mineral extraction. Land that is severely polluted cannot revert to productive
agricultural land to grow crops without great cost. This land will be lost, and will
poison flora and fauna, thus reducing the biodiversity of the Caribbean. Waste
from crops and animals should be composted and recycled for use as fertiliser.
Pesticides should be the last resort in managing pests, after cultural methods, so
that excessive runoff from fertilisers and pesticides is minimised.
Global warming
Figure 3.8 This landfill is an example of
land pollution.
greenhouse gases ▶
greenhouse effect ▶
atmosphere
• greenhouse gases
• trapped heat energy
increased production of greenhouse gases
(carbon dioxide and methane) by:
• combustion engines
• industry, bush fires
• farm animals, humans
• burning fossil fuels.
Eutrophication on the Rio Cobre, Jamaica.
The Earth is surrounded by the atmosphere, which is a blanket of air made
up of many gases. Two of these gases, carbon dioxide and methane, are called
greenhouse gases. In a greenhouse, the glass roof and walls trap the heat energy
of the sun and keep it within the greenhouse. This process maintains a warm
temperature in the greenhouse and the enclosed plants thrive.
Carbon dioxide and methane in the atmosphere act rather like a greenhouse,
producing what is known as the greenhouse effect. When the sun’s rays strike
the Earth, some heat energy is
absorbed and some is radiated back
heat energy
into space. The greenhouse gases
radiated
in the atmosphere trap the energy
into space
Sun
and keep it in, warming the air and
enabling all forms of life to survive.
If this energy was not trapped, it
• methane
would be too cold to sustain life on
incoming
• carbon dioxide
heat energy
Earth.
some heat energy
absorbed by the Earth
Earth’s surface
Earth warmed: global warming
some heat
energy
re-radiated
back from
the Earth
Figure 3.9 The greenhouse effect and
global warming.
31
Section A: Introduction to agriculture
Within the last century, there has been an increase in the production of greenhouse
gases due to human activity. Industrialisation, motorised transport, aeroplanes,
the burning of waste, bush fires and deforestation all lead to increased levels of
greenhouse gases in the atmosphere. This means that more heat energy is trapped
within the Earth’s atmosphere, which results in global warming.
Practical activity:
In groups, choose ONE method of
environmental degradation that is
a problem locally. Work together to
find a solution.
Global warming can produce these effects:
• a rise in sea level, causing loss of coastal land areas and affecting agriculture,
fishing and community life
• increased temperatures, which help some crops to grow, but prevent optimum
growth in other crops
• more frequent droughts, affecting water availability for both domestic and
agricultural use
• more powerful storms and hurricanes, which can ruin crops and livestock,
and destroy habitats and biodiversity
• a rise in sea temperature, which kills coral reefs and affects the ecosystem of
marine fisheries.
Coral reef destruction
Coral reefs are fragile ecosystems and are easily damaged by pollution. Polluted
water runs off the land, enters the sea and increases the growth of algae that
live on reefs. This kills the coral underneath the algae. Corals can be smothered
by sediments washed into the sea from rivers and coastal dredging activities.
Overfishing and tourist activities upset the ecological balance so that the physical
structure of the reefs, as well as the plants and animals that live in them, suffer
significant damage.
When sea temperatures rise, the coral dies and loses its colour. Weakened coral
can be attacked by bacterial and viral diseases. The invasion of coral reefs in the
Caribbean by species such as the Indo-Pacific lionfish could also alter the shoreline
ecosystem of mangroves, as well as cause further damage to the reefs.
deforestation ▶
Deforestation
Five hundred years ago, most of the Caribbean was covered in dense tropical
forest. There are still many areas covered in natural forest, but an increasing
population means that there is pressure to clear land for crop production, industry
and housing (deforestation). Forests are cleared and wood is used for fuel, but
there are few policies for replanting trees. The forested areas that remain are in
mountainous regions with high rainfall. These regions are less accessible to the
machinery needed to clear the land for farming.
Natural hazards such as forest fires and tropical storms also destroy forests.
Hurricanes uproot forests and strip leaves, leaving trees bare. Volcanic activity
produces poisonous gases and hot lava, which has affected forests in Montserrat
and St Vincent.
It is important to retain forests as they:
• provide areas for recreation, for example, nature reserves and national parks,
which have facilities for hiking and other forms of relaxation
• control soil erosion by providing cover to break up the force of the rain on
the soil
• absorb carbon dioxide and provide oxygen through photosynthesis
• are an important source of timber for building and furniture.
Figure 3.10 Deforestation.
32
Within protected areas of forest, replanting and maintenance work can be carried
out to avoid over-exploitation.
3: Challenges in agriculture
Availability of labour
Movement away from rural areas
There is a global shortage of labour for agricultural work. Farming is done in
rural areas but people in these areas are moving to urban areas for better services
and infrastructure. Around the world, as people sell their farms and move to
cities for easier lives, the land is being bought up. Sometimes this is for housing
development, but often small farms are being consolidated into larger land
holdings. Globally there has been an increase in mechanisation, which has led to
more stable food security, despite the reduction in farmers.
Practical activity:
Visit and research a rural
community near you. Design an
advertising campaign to encourage
young people to remain in the rural
areas and become farmers.
Ageing farming population
As young people are choosing the better services and infrastructure of urban
areas, along with the opportunities for continuing education and entertainment
that cities can offer, fewer people remain in the rural areas to work on farms.
This means that the currently active farmers in the Caribbean are ageing. This
is causing difficulties as farming is physical work and tasks that a young person
could easily complete will challenge an older person.
Limited participation of youth
Population movements are complex. It is possible that younger people will return
to rural areas to manage family farms later in life. However, fewer young people
are training in agriculture and becoming farmers, particularly in areas where there
is less opportunity to use technology. This is unfortunate, as more young farming
entrepreneurs are required for new ideas and the development of innovations to
solve agricultural challenges.
Food safety
More people now travel within the Caribbean region and around the world for
business and pleasure. Some may visit farms abroad and inadvertently bring
seed, plant, soil or animal materials into Caribbean territories. These materials
may contain pests and diseases, which can spread rapidly and cause damage to
domestic agriculture.
Sanitary and phyto-sanitary (SPS) certification procedures govern the import
and export of plants, animals and their products. This happens both nationally
and regionally. Normally, licences are issued for import and export purposes.
Incoming plants and animals need to be quarantined and tested for diseases and
then require a certificate declaring them disease-free before they will be released
for propagation into the country.
Governments sometimes impose restrictions on the import of certain agricultural
products, for example, poultry (chickens, eggs) and beef, from countries that have
experienced ‘bird flu’ or ‘mad cow’ disease. Agricultural workers associated with
these outbreaks are also monitored to ensure that diseases are not transmitted to
other farms and that no agricultural pests or diseases are brought into the workers’
home countries.
Natural disasters
Figure 3.11 Damage to agriculture
following a hurricane.
Each year, Caribbean countries are threatened by loss of life, property damage and
social disruption as a result of natural disasters. Tropical storms, hurricanes, tidal
waves, heavy rains and droughts have all occurred in the last 30 years. Disasters
have cost the region billions of dollars and have damaged economic health and
development.
33
Section A: Introduction to agriculture
Hurricane Irma, 30 August to 13 September 2017,
affected crop production and harvest
Hurricane Irma was the first Category 5 hurricane of the 2017 season. It caused widespread damage to the northeastern
Caribbean, before continuing to Florida, USA. The high winds caused extensive crop damage, and heavy rains
washed away soil and plants. High waves, landslides and flooding occurred throughout the affected areas of
the Caribbean. Despite landfalls in Antigua and Barbuda, St Martin, the Bahamas and Cuba, the number of
deaths was low. However, due to the destruction caused by Hurricane Irma, it is the costliest Caribbean
hurricane on record after Hurricane Maria (which occurred later in September 2017).
Practical activity:
Research the risk of tsunamis in
the Caribbean. Create a poster with
your findings.
natural hazards ▶
The Caribbean Disaster Emergency Response Agency (CDERA) has developed
a strategy for the management of such disasters, known as the Comprehensive
Disaster Management (CDM) strategy. This places emphasis on the benefits of
strengthening the infrastructure so that installations are as storm-resistant as
possible. Investment in roads, drainage systems, electrical and water services,
schools and hospitals saves money in the long term, as the cost of clean-up
procedures is usually greater and involves rehabilitation and total rebuilding. This
strategy depends on persuading individual governments to make investments.
Natural hazards are hazards that are not caused by people. They occur at, or
below, the surface of the Earth, and can cause loss of life and damage to property
and land. They can cause short-term or long-term changes to an environment.
The most common natural hazards in the Caribbean are volcanic eruptions,
earthquakes, floods and hurricanes. Some of their effects are shown in Table 3.1.
Natural hazard
Effect on the environment
Volcanic eruption
Eruptions deposit ash on the surrounding countryside, and fires caused by burning gas and hot lava destroy vegetation. Deposits of
debris are left on land. The most recent eruptions on Montserrat have left much of the island uninhabitable.
Minor earthquakes are not uncommon in the eastern Caribbean, and Jamaica lies on an active fault zone. Modern Kingston dates
from the destruction of Port Royal in 1907. Submarine earthquakes may trigger tsunamis that flood coastal areas and destroy buildings
and infrastructure.
Flooding is widespread as storms bring torrential rainfall in a short time. Mountainous islands are most vulnerable because lowlying land floods to several metres as water drains from high ground. Water destroys crops, kills animals and brings about soil
erosion. Areas at risk have been identified and early warnings can be given. Apart from tropical storms, flooding can be caused by
deforestation, mining and silting up of rivers.
Hurricanes, such as Irma in 2017, cause wind damage, wave damage, storm surges in coastal areas and flooding. Crops and trees are
damaged by high winds and storm surges pollute inland areas with seawater. Seawater is poisonous to plants and livestock, and the
soil remains contaminated until the salt is removed by rainwater.
Earthquake
Flood
Hurricane
Table 3.1 Natural hazards and their effects on the environment.
Volcanic eruption of Montserrat, 1995 – 1997,
affected farming communities
The Soufriere Hills eruption began with small earthquakes, then the small island was devastated by pyroclastic flows. The
Montserrat population of 11 000 people was evacuated to the north of the island and to other Caribbean islands during 1995.
Nineteen people were killed, as they had decided to stay behind to look after their crops. Many roads, homes and buildings
were destroyed by lava, including the only hospital and the airport.
34
3: Challenges in agriculture
Revision map
Pests and crop
diseases more
abundant
Soil water
needs to be
conserved /
used efficiently
Water
shortage
Good drainage
needed
Hurricanes
and high winds
Wet season
Dry season
Lack of
infrastructure
Topography –
hilly areas are
difficult to farm
Investment in
rural infrastructural
development brings
agricultural
development and
food security
Climate
affects
agriculture
Challenges
in agriculture
Agriculture in the
Caribbean needs more
mechanisation
to be more
efficient
Problems with
the use of
heavy machinery
and transport
produce
More extension
officers needed
to spread useful
information to
farmers
Plant, soil
and animal material
brought into the country
illegally may contain pests
and diseases that will
negatively affect
domestic
agriculture
Ageing farming
population as
young people are
migrating to
urban areas
Natural
disasters can
damage crops and
livestock
Environmental
degradation
Caused by pollution,
deforestation and
natural disasters
Praedial
larceny
is a major
problem
Measures can be
taken to minimise
these effects without
reducing the efficiency
of agriculture
35
Section A: Introduction to agriculture
Examination-style questions
Multiple-choice questions
Write down the number of the question followed by the letter of the correct answer.
1. Mountainous areas in the Caribbean are difficult to farm because:
A it is too windy
B the terrain is too steep to use tractors
C few people live there
D there is insufficient rainfall.
2. The main greenhouse gases are:
A carbon dioxide and oxygen
B sulphur dioxide and methane
C carbon dioxide and methane
D methane and sulphur dioxide.
3. Global warming may cause:
A a fall in sea level
B a rise in sea temperature
C fewer hurricanes
D a longer wet season.
4. Species diversity is:
A a range of habitats
B a diversity of genes
C a diversity of organisms
D a populations of organisms in an ecosystem.
5. Which of the following is NOT a cause of environmental degradation?
A Forest fires
B Overfishing
C Land fragmentation
D Atmospheric pollution
Short-answer and essay-type questions
6. (a) Explain the meaning of land tenure.
(b) Describe how it can affect local and regional agriculture.
7. (a) Describe the importance of mechanisation in agriculture.
(b) Why is mechanisation limited in scope and usage in most Caribbean countries?
8. (a) What is praedial larceny?
(b) How does it affect Caribbean farmers?
(c) Suggest THREE ways in which the problem can be solved.
9. (a) List FOUR environmental issues that affect the Caribbean region.
(b) Discuss how each of the issues you have listed affects farming in the region.
10. (a) Define ‘globalisation’ as applied to farming.
(b) Show how progressive farmers in the Caribbean can benefit from globalisation.
11. Discuss the problems that face farmers who cultivate crops on hilly or mountainous terrain.
12. Consider the effects of global warming and how farming in the Caribbean could be affected.
36
Section B: Crop production
4
Anatomy and
physiology
By the end of this unit you should be able to:
✔
✔
✔
✔
✔
✔
Concept map
explain the uses of plants in agriculture
describe the internal and external structure of plants
describe the physiological functions of plants
distinguish between sexual and asexual reproduction in plants
demonstrate the techniques used in plant propagation
describe conditions necessary for germination of seeds, growing of
seedlings and vegetative propagation.
Anatomy and physiology
Uses of plants in agriculture
Structure and
functions of
plants
Monocots
and dicots
Seeds
Stem
Root
Leaf
Sexual
reproduction
in plants
Parts of
a flower
Pollination
Fertilisation
Seed
formation
Asexual
reproduction and
techniques used in
plant propagation
Natural
Rhizome
Sucker
Corm
Bulb
Tuber
Runner
Stolon
Artificial
Budding
Grafting
Tissue culture
Layering
Stem cutting
Root cutting
Crop
production
Sexual and
asexual
reproduction
Advantages
Disadvantages
Conditions for
growing seedlings
and vegetative
propagation
Plant
processes
Photosynthesis
Types
Respiration
Hypogeal
Epigeal
Translocation
Conditions
Light
Water
Temperature
Sowing seeds
and care of
seedlings
Absorption
Transportation
Photoperiodism
Phototropism
37
Section B: Crop production
4.1 The uses of plants in agriculture
The most common use of plants in agriculture is to grow crops to provide food for
people and animals. This use makes plants crucial to the development of a region.
Plants used in agriculture have significant economic importance, as large amounts
of land are managed by growing agricultural plants. Sugar cane is now a popular
component of biodiesel, so its food use has been reduced as it is now grown as
a fuel. Choices such as this affect the food security of a country, particularly on
an island, where good agricultural land is in short supply. If a farmer chooses to
grow sugar cane for biodiesel because the crop has a higher value than maize
(corn) for food, the farmer will earn more money for the products from the land,
while at the same time not growing food. Crops grown for medicine or cosmetics
are less common. One example is aloe vera, which is grown specifically for its
calming, soothing properties. Horticultural plants are also grown for medicinal,
therapeutic and recreational purposes. The cultivation of horticultural plants
provides employment and income for the producers, particularly ornamental
plants such as orchids and roses, which can be marketed locally, but are more
usually grown for the export market. Aside from being important economically
and providing us with food and fuel, plants provide health and religious benefits,
when they are planted in recreational areas.
Figure 4.1 Aloe vera.
4.2 The structure of plants
To cultivate crops, a farmer needs to understand plant structure. Crops can be
grown for their leaves (lettuce), leaf stalks (celery), stems (sugar cane), roots
(cassava), flowers (cauliflowers), fruits (bananas) and seeds (cocoa).
Different crops have different requirements and growth patterns, so a farmer
needs to consider the types of crops best suited to the environmental conditions
of the area.
Plant classification
seed plants, flowering plants ▶
monocotyledons ▶
dicotyledons ▶
family ▶
annuals ▶
biennials ▶
perennials ▶
herbs ▶
shrubs ▶
trees ▶
38
Plants are classified according to the following:
• Major group: Seed plants, which are flowering plants that produce both
flowers and seeds. They are further subdivided into monocotyledons and
dicotyledons.
• Family: Monocotyledons and dicotyledons can be divided up into smaller
groups, which have many features in common, for example, peas and beans
belong to the family Leguminosae.
• Life cycle: Some plants germinate, grow, flower, seed and die, completing
their life cycle in one growing season or in one year. These are the annuals,
for example, lettuce, peas, corn, tomatoes and bell peppers. Some plants take
two growing seasons or two years to complete their life cycle. These are the
biennials, for example, carrot, celery, dasheen or taro and beetroot. Others
continue to grow, flower and produce seeds for many years. These are the
perennials, for example, citrus, mango, cocoa and coffee.
• Growth habit: Herbs are plants with soft, non-woody stems, usually less than
2 m in height (parsley, bodi beans, coleus, balsam). Shrubs have stiff, woody
stems, produce branches close to the ground and grow to heights of less than
5 m (West Indian cherry, guava, hibiscus). Trees are tall woody plants with a
well-defined trunk and branches at some distance from the ground (mango,
breadfruit, cedar, teak, mahogany).
4: Anatomy and physiology
Figure 4.2 Bell peppers (left), dasheen (centre) and coffee (right).
Monocotyledons and dicotyledons
Monocotyledons, usually referred to as monocots, and dicotyledons, referred to as
dicots, are made up of a root system and a shoot system. They can be distinguished
by the structure of their seeds, arrangement of their flower parts, root systems and
the shape of their leaves. A comparison of the two groups is given in Table 4.1.
Monocots
Seeds have one cotyledon (seed leaf) and
an embryo.
Fibrous root systems.
Stems with scattered vascular bundles.
Practical activity:
Take a walk in your area to
photograph plants. When you
are back in your classroom, use
the table to identify monocots
and dicots by their visible
characteristics.
Dicots
Seeds have two cotyledons and an embryo.
Usually no cambium present in stem or root.
Long thin leaves with parallel veins.
Flower parts in threes, e.g. three petals, three
stamens; grass flowers lack brightly coloured
petals or sepals.
Mainly herbs and grasses, with few trees, e.g.
corn, rice, sugar cane, bamboo, orchids, ginger.
Tap root systems.
Stems with cylindrical arrangement of vascular
bundles.
Cambium usually present in stem and root.
Rounded, broader leaves with net-like
arrangement of veins.
Flower parts more numerous, often in fours
and fives, e.g. five petals, five stamens; obvious
petals and sepals, often brightly coloured.
Herbs, shrubs and trees, e.g. cabbage, cotton,
citrus.
Table 4.1 The major characteristics of monocots and dicots.
single
spikelet
stamens
single flower
whole grass plant
whole tomato plant
single flower
with sepals and
five petals
Figure 4.3 A grass plant (monocot) and a tomato plant (dicot).
39
Section B: Crop production
Plant structure
flower: contains
reproductive parts
flower bud
leaf: takes in carbon
dioxide; absorbs light
for photosynthesis
shoot
system
bud
stem: supports leaves
and flowers; transports
water and minerals
root branches
main root
root system:
provides
anchorage; takes
up water; takes
up minerals
Figure 4.4 The external structure of a typical flowering plant.
Figure 4.4 shows that the root system is below the ground and the shoot system
is above ground. The root system secures the plant and provides support. It also
takes up water and mineral ions from the soil. The shoot system supports leaves
and flowers, transports water from roots to leaves, and transports food made
in the leaves to other parts of the plant. The flowers contain the reproductive
structures and produce fruits, which contain seeds.
Practical activity:
Select plants with a variety of root
systems. Make drawings of the
different types of root systems.
Use microscopes to view the plant
structures.
Roots
tap roots ▶
fibrous roots ▶
adventitious roots ▶
aerial roots ▶
There are four main types of roots.
• Tap roots consist of a main, or tap, root with lateral roots growing out to the
side (tomato, mango).
• Fibrous roots consist of a cluster of roots growing from the base of the stem
(coconut palm, corn).
• Adventitious roots have their origin in plant tissues other than the root
tissue. They are not inherent to the tissue that they arise from, as they
originate in tissue that is above ground.
• Aerial roots grow above ground (Ficus, Philodendron).
tap
root
aerial
roots
fibrous
root
adventitious root
Figure 4.5 Main types of roots. Tap root systems are typical of dicots; fibrous root systems are found in monocots.
40
4: Anatomy and physiology
epidermis
cortex
endodermis
cambium
phloem
xylem
pericycle
Figure 4.6 The internal structure (transverse section) of a
young dicot root. The arrangement of the tissues in a young
monocot root is very similar.
Practical activity:
Choose a plant with a dicot
root system (cabbage, cotton or
citrus). Slice through a young root
(transverse section). Make drawings
of the young root and label the four
types of dicot tissue.
Dicot roots
The internal structure of a young dicot root is made up of four types
of tissues.
• Epidermis: This is a single layer of cells on the outside of the root
that protects the young root and absorbs water and mineral ions.
• Cortex: This forms most of the young root tissue, with many
unspecialised thin-walled cells.
• Endodermis: This is a single layer of cells that controls the
movement of soluble materials between the cortex and the
vascular tissue.
• Vascular tissue: This is a cylinder at the centre of the root, which
is made up of several different types of cells – xylem, phloem and
pericycle (see Table 4.2).
Tissue
Xylem
Location in root
In centre of root; can be star-shaped.
Phloem
Groups of cells found between the
projecting parts of the xylem.
Pericycle
Single narrow layer of cells just inside
the endodermis.
Functions
Transports water and mineral ions from
the soil to aerial parts of the plant.
Transports soluble food substances
from where they are made in leaves to
the roots.
Generates branch roots and the cambium
tissue, which can produce more vascular
tissue and the outer corky layer on older
roots.
Table 4.2 Vascular tissues: their location in the root and their functions.
Stems
herbaceous ▶
woody ▶
ITQ 1
What are the functions of xylem and
phloem in a root?
Monocot stems are soft and non-woody (herbaceous), and are often green and
carry out photosynthesis. Dicot stems are woody and are covered in a waterproof
layer of bark. The stems of most plants grow upright, but some have underground
stems called rhizomes. Cactus plants (cacti) have stems that are modified to store
water.
epidermis
vascular bundle
phloem
cambium
xylem
cortex
ITQ 2
How is the arrangement of tissues in
a stem different from the tissues in a
root?
dicot stem ▶
Figure 4.7 Cactus plant.
Figure 4.8 The internal structure (transverse section) of
a young dicot stem.
Dicot stem
A dicot stem is made up of the same tissues as the root, but they are arranged
differently.
• The epidermis has openings (stomata) where gas exchange occurs during
respiration and photosynthesis.
• There is no definite endodermis.
41
Section B: Crop production
• Vascular tissue is arranged around a central zone of cells called the pith.
• Each vascular bundle has cambium tissue located between the xylem and
phloem.
monocot stem ▶
ITQ 3
What are the external differences
between monocot and dicot leaves?
Monocot stem
The arrangement of tissues in a young monocot stem differs from a dicot stem.
• The vascular bundles are scattered throughout the stem.
• There is no distinction between the cortex and the pith.
• Usually, there is no cambium between the xylem and phloem in the
vascular bundles.
Leaves
Practical activity:
Slice young stems (of monocots and
dicots) to form transverse sections.
Use microscopes to view these
sections. Sketch what you see and
label your sketches.
A typical leaf consists of:
• a leaf blade (lamina), which is the flat part
• a leaf stalk (petiole), which attaches the leaf to the stem
• a midrib (main vein), that holds the transporting tissues
• a network of smaller veins.
The tip of the leaf is called the apex. The edges of the leaf are referred to as
the margin.
The leaves of monocots (for example, grasses) are long and thin with no definite
midrib, but with parallel veins. The leaves of dicots vary in shape and arrangement,
with a midrib and a network of smaller veins.
simple leaves ▶
compound leaves ▶
pointed lobes
Simple leaves have a leaf blade that is not divided, and the margin may be
smooth (cashew), serrated (hibiscus) or lobed (castor oil). In compound leaves,
the blade is divided into leaflets attached to the leaf stalk. The leaflets may be
arranged like the fingers on a hand (palmate) or in a row on either side of the
midrib (pinnate). Examples are shown in Figure 4.10.
midrib
petiole
Figure 4.9 The external features of a
typical leaf.
monocot leaf
pinnate leaf
simple dicot leaf
palmate leaf
Figure 4.10 Types of leaf.
Leaves may be modified for food storage (fleshy leaf bases of onion), for protection
(outer scale leaves of onion) and for extra photosynthesis (flattened leaf bases of
Acacia).
Internally, leaves are made up of epidermis, mesophyll and vascular tissues (see
Table 4.3).
42
4: Anatomy and physiology
Type of tissue
Epidermis
Position in leaf and characteristics
• Upper epidermis: single layer of cells covering upper
surface; layer covered by waxy cuticle.
• Lower epidermis: single layer of cells covering lower
surface; contains more stomata than the upper epidermis.
Mesophyll
Tissues between the upper and lower epidermis; cells
contain chloroplasts; divided into:
• palisade mesophyll in the upper part of the leaf; can
be one to three layers thick; contains large numbers of
chloroplasts
• spongy mesophyll in the lower part of the leaf; cells are
irregularly-shaped and contain air spaces; contains fewer
chloroplasts than palisade cells.
• Vascular tissue is composed of xylem and phloem and is
• The xylem transports water and mineral ions to the leaf, and
present in the main vein and the network of smaller veins.
supports the leaf tissues.
• The phloem transports sugars from the leaf to other parts of
the plant.
Vascular tissue
Functions
• Protects the internal tissues.
• Cuticle on upper epidermis slows down the evaporation of water
from the leaf.
• Stomata allow gas exchange.
• The chloroplasts in the mesophyll cells contain chlorophyll, which
absorbs light energy needed for photosynthesis.
• Most photosynthesis occurs in the palisade mesophyll; air spaces
in spongy mesophyll allow the circulation of gases needed for
photosynthesis and respiration.
Table 4.3 The internal tissues of a leaf, their characteristic features and functions.
cuticle
cell wall
upper epidermis
palisade mesophyll cells
xylem vessel
phloem
air space saturated with water vapour
spongy mesophyll cells
moist cell wall
lower epidermis
stoma (gap between
the guard cells)
guard cell
Figure 4.11 The internal structure of a dicot leaf.
ITQ 4
What are the functions of the
epidermis of the leaf?
The arrangement of the tissues in a monocot leaf (for example, grass) differs from
that in a dicot leaf.
• There is no palisade mesophyll.
• There is less distinction between the upper and lower epidermis.
• There is no definite midrib.
Seeds
testa, embryo ▶
A seed is surrounded by the seed coat or testa. A seed contains the embryo,
which will develop into a young plant. It also contains a store of food for the
embryo.
Dicot seed
The broad bean seed is an example of a dicot seed. It has these external features:
• the testa, which protects the embryo and the food store
• a tiny hole, called the micropyle, through which water enters before
germination can occur
• the scar (hilum) showing where the seed was attached to the pod.
43
Section B: Crop production
cotyledons ▶
radicle ▶
plumule ▶
Practical activity:
Collect living material (plants,
seeds, bark, leaves, and so on)
Create a collage showing the
internal and external structures of
monocot and dicot leaves using the
material you have collected. Label
your collage.
If the testa is removed, there are two cotyledons, or seed leaves. The embryo
consists of the radicle, which grows into the root of the seedling, and the
plumule, which develops into the shoot system. These features are shown in
Figure 4.12.
a) External appearance of
a broad bean seed
b) The testa removed
seed leaves (cotyledons)
contain food store
seed coat
or testa
tiny hole
(micropyle) where
water enters before
germination
plumule
(embryo shoot)
plumule
(embryo shoot)
embryo
scar where seed was
attached to pod
Figure 4.12 Internal and external structure of a dicot seed (broad bean).
ITQ 5
State where food is stored in a maize
seed and in a bean seed.
Monocot seed
A monocot seed, such as the maize grain in Figure 4.13, differs from the broad
bean seed.
• The outer protective coat is formed from the fusion of the testa and the fruit
wall, as the maize grain is a one-seeded fruit.
• There is only one cotyledon.
• The food store, called the endosperm, is separate from the cotyledon.
Section through a maize grain
Practical activity:
Examine different seed types.
Start with maize and broad
bean. Investigate their external
and internal structures. Make
drawings and write notes about
the differences that you find.
Compare your drawings with your
classmates’ drawings. Did you note
the same differences?
A whole maize grain
fruit wall
fruit wall
food store
plumule
radicle
position of cotyledon
embryo
cotyledon
position of embryo
point of attachment
to cob
Note that the maize grain is a one-seeded fruit; the testa and fruit wall are fused
Figure 4.13 Internal and external structure of a monocot seed (maize grain).
4.3 Plant processes
Photosynthesis
photosynthesis ▶
Photosynthesis is how plants make food. Plants manufacture carbohydrates
(sugars and starches) in their leaves, which have the green pigment chlorophyll.
This process also uses carbon dioxide from the air, water from the soil and light
(usually sunlight).
Here are the chemical and word equations that summarise photosynthesis.
Chemical equation: 6H2O + 6CO2 + ENERGY (light) ➞ C6H12O6 + 6O2
Word equation:water + carbon dioxide
➞ glucose (carbohydrate)
+ oxygen
+ ENERGY (light)
44
4: Anatomy and physiology
Photosynthesis is affected by carbon dioxide concentration, light intensity,
temperature and soil water supply.
ITQ 6
How does light intensity affect the
rate of photosynthesis?
The sugars created during photosynthesis are used by the plant in the following
ways:
• respiration, which releases energy for cell division and growth
• making starch, which is stored in leaves, tubers and seeds
• creating proteins and lipids, which are essential for the plant to grow well and
develop stems, leaves and reproductive structures.
Practical activity:
Experiment to show how light affects photosynthesis
1. Set up the apparatus as shown in the diagram.
bubbles
desk lamp
pondweed
move lamp away
by 10 cm intervals
up to 50 cm
ruler
2. Leave for five minutes for the pondweed to get used to the
light intensity.
3. Count the number of bubbles given off in one minute.
4. Record your result in a table like the one shown here.
Distance from
the light
10 cm
20 cm
30 cm
40 cm
50 cm
Number of oxygen bubbles
in one minute
5. Move the light 10 cm further away.
6. Leave for five minutes for the pondweed to adjust again.
7. Count the number of bubbles given off in one minute and
record the result.
8. Repeat the process, moving the lamp further away by 10 cm
each time until it is 50 cm away.
9. Use your data to draw a graph showing how light intensity
affects photosynthesis.
The x-axis should be distance from the light.
The y-axis should be number of bubbles.
Remember to give your graph a title and label both axes.
10. Does light intensity affect photosynthesis? Describe your
results and explain the pattern on your graph.
Respiration
respiration ▶
Respiration is how sugar is broken down (oxidised), to release energy for growth
and development. It is the opposite of photosynthesis, which is how molecules
that store energy are built up.
Here is the respiration equation.
➞ 6CO2 + 6H2O + ENERGY
Chemical equation: C6H12O6 + 6O2
Word equation:
glucose + oxygen ➞ carbon dioxide + water + ENERGY
ITQ 7
Give reasons why plants need energy.
The energy released is essential for plant growth and the formation of new cells.
It powers all cell functions and the movement of substances throughout the plant.
45
Section B: Crop production
Practical activity:
Experiment to show that energy is given off by respiring seeds
This experiment investigates aerobic respiration in germinating peas. Germinating peas are used because they grow quickly. This
growth requires a lot of energy for cell division, so the rate of respiration in germinating peas is high. This experiment shows that
energy is given off by the germinating peas by the amount of heat generated in the process.
1. Set up two vacuum flasks as shown in the diagram. The flasks
thermometer
will prevent heat loss.
2. Halve the quantity of germinating peas. Place one
wet cotton
half of the peas in the first vacuum flask. Boil the
other half of the peas. Let the peas cool to room
temperature and then place them in the second flask.
The second flask is the control.
3. Insert a thermometer into the top of each vacuum
boiled
germinating
seeds
seeds
flask. Use wet cotton wool to seal the top of each
flask and around the thermometers to prevent heat
escaping.
4. Measure the temperature of both flasks hourly.
5. Record your data in a table like the one shown here.
Time
10:00
11:00
Temperature (germinating peas)
Temperature (boiled peas)
6. Draw a graph to show the amount of heat produced in the respiration process of the germinating peas.
The x-axis should be time.
The y-axis should be temperature.
Remember to give your graph a title and label both axes.
7. Do germinating peas generate heat energy as they respire? Describe your results and explain the pattern on your graph.
Transpiration
transpiration ▶
stomata ▶
Practical activity:
Carry out a simple experiment to
show that water vapour is lost from
the leaves of a plant. Use cobalt
chloride paper, which is blue when
dry and goes pink when it is wet.
transpiration stream ▶
46
Transpiration is the process by which plants lose water from their leaves and
green stems. The water vapour escapes through stomata, which are small holes
on the leaves or green stems.
Transpiration is the loss of water, in the form of water vapour, and results in
the uptake and transport of water through the plant from roots to leaves.
Transpiration is affected by environmental factors such as sunlight, temperature,
wind, humidity and soil-water content.
Water is essential for plant growth because:
• it keeps cells turgid (full of water), resulting in the rigidity of leaves and soft
stems
• it transports mineral ions around the plant from the roots to the leaves
• it is needed for photosynthesis.
The loss of water vapour from the leaves exerts a ‘pull’ on the column of water.
This ‘pull’ extends from the leaves, through the stem and down to the roots. The
column is referred to as the transpiration stream. There is also a cooling effect
on the leaves as water evaporates from cells.
4: Anatomy and physiology
wilting ▶
Wilting
If transpiration exceeds absorption of water by the plant, then cells will wilt. This
may be temporary at first and can be reversed if water is supplied, but permanent
wilting results in death. Repeated temporary wilting in crop plants causes a
reduction in cell division, poor development of tissues, stunted growth and poor
yield.
Absorption
Cells need to take up water, mineral ions and food substances. Cells also need to
get rid of waste materials. All substances need to pass through the cell membranes
to get in or out of cells. Movement through cell membranes can occur passively
by diffusion, or actively in a process requiring energy.
Absorption of water is essential for photosynthesis, respiration and the movement
of water, mineral ions and food substances. All these processes are interrelated
and contribute to plant growth and development. If the absorption of water is
reduced, it will affect growth and development. Wilting will occur if plants cannot
absorb sufficient water.
Figure 4.14 Diffusion.
diffusion ▶
osmosis ▶
Diffusion
Diffusion occurs when molecules move from higher concentrations to lower
concentrations. Diffusion will continue until the concentration everywhere is the
same. No energy is required by the plant for diffusion to happen.
Osmosis
Osmosis is the process of diffusion of water across a partially permeable membrane
from a dilute solution (high concentration of water molecules) to a concentrated
solution (lower concentration of water molecules).
Plant roots take up water from the soil solution by means of their root hairs. The
concentration of the soil solution is more dilute than the concentration of the
cell sap, so water molecules pass from the soil solution into the root hair cells.
This is an example of osmosis taking place. The movement of water within the
plant is by osmosis, and occurs along concentration gradients (from areas of high
concentration to areas of low concentration).
active transport ▶
Active transport
Mineral ions are transported from the roots to other parts of the plant and used
by the cells. Sometimes mineral ions enter the roots by diffusion. However, some
mineral ions may be taken up by active transport. This process requires energy
from respiration to move the ions against a concentration gradient.
Translocation
translocation ▶
Translocation is the process of transporting water, mineral ions and food
substances in specialised tissues within the plant. The specialised tissues are:
• xylem, composed of vessels and tracheids, which transports water and mineral
ions
• phloem, composed of sieve tubes and companion cells, which transports food
substances in solution.
Water and mineral ions from the soil move upwards through the xylem to
the leaves. Food materials (sugars) manufactured in leaves are translocated
downwards to the lower parts of the plant for storage. Soluble food substances
move from storage organs to growing points, buds, flowers and fruits.
47
Section B: Crop production
Translocation is important for growth as it supplies the nutritional needs of plant
cells, helps to maintain turgidity, and is necessary for the development of storage
organs.
Practical activity:
Experiment to demonstrate the effect of osmosis on plant tissue
When a plant cell is immersed in water there is a concentration gradient from the high concentration of the water to the low
concentration inside the cell. Water will enter the cell by osmosis and the cell will expand. When the plant cell is placed in a
concentrated solution, water will travel across the concentration gradient from the cell to the solution, making the cell shrink.
1. Peel a potato.
2. Cut three identically sized pieces of potato 1 cm × 1 cm × 3 cm.
3. Weigh each piece of potato carefully (include two decimal places).
4. Place each piece of potato in a test tube.
5. To test tube A, add 10 cm³ of 0.5 molar sugar solution.
6. To test tube B, add 10 cm³ of 0.25 molar sugar solution.
7. To test tube C, add 10 cm³ of distilled water.
8. Leave the experiment overnight to allow osmosis to take place.
9. Remove the potato pieces from the test tubes. Remove surface water with a paper towel, but do not press.
10. Weigh the potato pieces carefully again (to two decimal places) and measure the length of each piece.
11. Describe your results and explain them using the words below.
osmosis
high concentration
low concentration
shrink
expand
travel
Practical activity:
Demonstration of water transport in a plant
1. Place a stick of celery in a beaker of water. The leaves should be above the water.
2. Add drops of dye or ink to the water in the beaker. Add enough drops to colour
the water brightly. Use another beaker of water and a stick of celery, but this
time without dye, as a control.
3. After a few hours, remove the celery and cut it into transverse sections to
observe how water has been transported.
4. Describe how the water is moving through the plant.
red
water
clear
water
Phototropism
phototropism ▶
light source
Figure 4.15 Positive phototropism in
seedlings.
photoperiodism ▶
48
Phototropism is plant growth in response to the direction of light. If the tips of
plant shoots are exposed to light, they will bend and grow towards it. This is an
example of positive phototropism. It benefits the plant as it places the leaves in the
best position for photosynthesis. Usually, plants respond by bending their stems
towards the light. This can be seen clearly if seedlings are kept on a windowsill.
Photoperiodism
Photoperiodism refers to the influence of day length (duration of light) on
the production of flowers. In temperate countries, there is some variation in the
number of daylight hours due to the winter and summer seasons. In the tropics
and the Caribbean, the variation in hours of daylight is not as great, but the effect
can still be seen in some plants. Based on the effects of day length on growth and
flowering, plants can be divided into three groups (see Table 4.4).
4: Anatomy and physiology
Poinsettia, Trinidad
In the Caribbean, artificial techniques are used to bring certain short-day
plants, such as poinsettias, into flower around Christmas time when they
are in demand. The plants are kept in a vegetative state by keeping them in
artificially long days, and then induced to flower by exposing them to shorter
day lengths. The characteristic red leaves result from the plant being kept in
total darkness for the last eight weeks before being sold or shown. This
can be done by controlling timers in a plant nursery, or by simply
covering the plant in a black bag, which prevents the light
reaching the leaves.
Figure 4.16
Long-day plants
Produce vegetative growth
when the day length is short.
Produce flowers when the day
length is long.
Short-day plants
Produce vegetative growth
when the day length is long.
Produce flowers when the day
length is short.
Examples: radish, beetroot,
petunia
Examples: pigeon pea,
poinsettia, chrysanthemum
Poinsettia.
Day-neutral plants
Insensitive to day length.
Grow vegetatively to maturity
and produce flowers all year
round.
Examples: ochro, cucumber,
carrot, tomato
Table 4.4 Effects of day length on growth and flowering.
4.4 Sexual and asexual reproduction in plants
Sexual reproduction
hermaphrodite ▶
receptacle ▶
calyx ▶
corolla ▶
stamens ▶
anthers ▶
carpels ▶
stigma ▶
The flowers of seed plants contain the organs of sexual reproduction. Most
flowers, for example, guava, contain both male and female parts in one flower and
are called hermaphrodite. But other plants, for example, pumpkins, produce
separate male flowers and female flowers on the same plant.
Parts of a flower
A typical flower has the following parts:
• a flower stalk, or pedicel, which attaches the flower to the stem
• a receptacle, which is the swollen tip of the pedicel that all the other floral
parts are attached to
• a ring of sepals called the calyx, which is usually green and protects the other
flower parts when in a bud
• a ring of petals called the corolla, which is usually brightly coloured to attract
pollinating insects
• the male parts of the flower called stamens; each stamen consists of a
filament or stalk that has anthers that form the pollen grains containing the
male gametes
• the female parts of the flower called carpels; each carpel consists of a
receptive surface (the stigma) attached to the ovary by the style; the ovary
contains ovules, which contain the female gametes, or egg cells.
49
Section B: Crop production
Male flowers have all the above parts except the carpels. Female flowers do not
have stamens.
stigma and style
petal
ovule
carpel
nectary
sepal
anther
filament
stamen
receptacle
flower
stalk
Figure 4.17 The parts of a typical flower (this flower has both male and female parts).
ITQ 8
Name the parts of the flower
concerned with the production of
the male gametes.
pollination, self-pollination ▶
cross-pollination ▶
The ovules, inside the ovary, are the potential seeds. Depending on the species,
flowers may have one or more carpels and the number of ovules in each carpel
may vary. The number of stamens varies and their location and size depend on
the method of pollination.
Pollination
Pollination is the transfer of pollen from the anthers to the stigma. In selfpollination, the pollen may be transferred from the anthers to the stigma of the
same flower or to another flower on the same plant. Cross-pollination is when
pollen is transferred from the anthers of one flower to the stigma of another
flower on a different plant of the same species.
Pollination is essential for the production of economic crops, such as cereals and
fruits. Increased pollination leads to increased yields, which results in higher
incomes for the farmers. Cross-pollination is used in plant breeding to increase
the vigour of a species and to produce plants that are more resistant to pests and
diseases. Farmers are encouraged to place beehives in their orchards and to avoid
excessive use of insecticides during the flowering period of crops. These measures
increase the chance of cross-pollination.
Pollination can be done by people, birds and other small animals, but the main
agents are wind and insects. Wind-pollinated flowers and insect-pollinated
flowers are adapted to the method of pollination (see Table 4.5).
Practical activity:
Look at pollen from a windpollinated flower and an insectpollinated flower. Make notes on
the differences that you observe.
Record your observations in a table.
Wind-pollinated flowers
Flowers are often small; petals and sepals
may be absent; no scent.
No nectaries.
Anthers have long filaments and dangle
outside the flower.
Stigmas are long and feathery to trap the
pollen.
Very large amounts of pollen produced.
Pollen grains are small, light and smooth.
Examples: grasses, cereals
Insect-pollinated flowers
Flowers are often large, with brightly coloured petals
to attract insects; may be scented.
Nectaries produce sugary nectar to attract insects.
Anthers have short filaments and are fixed inside the
flower.
Stigmas are sticky so that pollen from insect’s body
attaches.
Much smaller amounts of pollen produced.
Pollen grains are heavier and sticky; the outer wall is
often sculptured.
Examples: beans, guavas
Table 4.5 A comparison of wind-pollinated and insect-pollinated flowers.
50
4: Anatomy and physiology
fertilisation, male gamete, female gamete ▶
ITQ 9
Describe what happens during
fertilisation.
seed formation ▶
Fertilisation
Fertilisation is the fusion (joining) of a male gamete with a female gamete
to form a zygote. This develops into the embryo. After pollination, pollen grains
germinate on the surface of the stigma, and pollen tubes grow down through the
tissues of the style to the ovary. At the tip of each pollen tube are three nuclei: two
male nuclei (the male gametes) and a pollen tube nucleus. When the pollen tube
reaches an ovule, the tip releases the nuclei. One male nucleus fuses with the egg
cell (female gamete) in the ovule to form the zygote. The second fuses with nuclei
in the ovule to form food storage tissue. The zygote develops into the embryo.
Seed formation
After fertilisation, seed formation occurs. The fertilised egg develops into the
embryo of the new plant. Food made during photosynthesis in the parent plant is
stored in the endosperm tissue. In some seeds, such as peas and beans, the food
store develops in two cotyledons, which become swollen. In other seeds, such
as castor beans and maize, food is not stored in the cotyledons, but remains as a
separate tissue. The tissues that surrounded the ovule in the ovary become the
seed coat.
Asexual reproduction
asexual reproduction ▶
organs of perennation ▶
Asexual reproduction refers to the propagation of plants by vegetative parts
and does not involve gametes. Asexual reproduction can be achieved by natural
methods, for example, tubers, suckers and rhizomes, or artificially by cuttings,
budding, grafting and using tissue culture.
Natural methods of asexual reproduction
Several crops produce vegetative parts (see Figure 4.18), which farmers use as
planting materials. A farmer can grow bananas from banana suckers, yams from
yam tubers and eddoes from eddoe corms. These vegetative parts are referred
to as organs of perennation. They store food, enabling the plant to survive in
a dormant state during the dry season and to resume growth when conditions
become favourable (see Table 4.6). Many of the plant parts used in natural
vegetative propagation (for example, potato tubers) are eaten by people and
animals.
sucker
root tuber,
e.g. sweet potato
corm
onion bulb
runner
rhizome e.g. ginger
stolon e.g. grasses
Figure 4.18 Examples of vegetative organs.
51
Section B: Crop production
Vegetative organs
Sucker
Tuber
Rhizome
Corm
Bulb
Stolon
Runner
Description
Underground shoot growing from the basal part of the parent
plant.
Swollen underground stem or root:
• stem tuber: with axillary buds and scale leaves
• root tuber: without axillary buds and scale leaves
Thick, underground stem: branched with axillary and terminal
buds and scale leaves.
Short, swollen underground stem arising from the parent plant.
Very short, disc-like stem with tightly rolled, fleshy and scale
leaves.
Slender, creeping stem: usually underground, branched, rooting at
the nodes.
Creeping stem: usually on the soil surface, with long internodes,
rooting at the nodes.
Example
Banana; pineapple
• Yam and Irish potato are stem tubers
• Sweet potato and cassava are root tubers (sweet
potato, with portion of stem attached, will sprout but
cassava does not sprout)
Ginger; saffron; canna lily; ginger lily
Eddo; tannia; dasheen
Onion; lily
Bahama grass; nut grass
Strawberry; savanna grass; pumpkin
Table 4.6 Some organs of perennation.
Sexual and asexual reproduction in relation to crop production
Sexual reproduction and crop plants
Sexual reproduction results in fruits and seeds, so it is vital in the production of
rice, maize, cereals and fruits of all kinds.
The production of seeds is also necessary if the farmer is to grow other crops,
as most leaf and root vegetables are raised from seed. In the past, the farmer
would allow some of the crop to produce seeds, which were kept for planting the
following year. Nowadays, the farmer buys seeds from a seed merchant, expecting
a high percentage to germinate and grow.
Asexual reproduction and crop plants
Growing some crops from seed (for example, fruit trees) takes a long time and the
plants are not always ‘true to type’. In such cases, vegetative means of propagation
can be used so that the offspring are genetically identical to the parent plant.
Some plants, such as banana, pineapple and breadfruit, do not produce viable
seeds. These are often propagated artificially.
Table 4.7 describes the advantages and disadvantages of asexual reproduction.
Advantages
• New plants are true to type, as they are
genetically identical to the parent plant.
• Large numbers of plants can be produced in a
short time.
• Scions can be grafted on to disease-resistant
stocks.
• Plants that do not produce viable seeds can
be propagated.
• Budding and grafting scions on to dwarf
stocks (plants that are smaller than normal
for their species) make it more convenient for
farmers to prune and harvest the crop.
• Scions can be chosen for their fruit quality.
Disadvantages
• There is lack of variety and diversity in the
new plants.
• The risk of total crop loss through disease is
greater than with seeds.
• Some of the techniques involved in artificial
propagation require skills that may not be
available, e.g. budding and grafting.
• Techniques such as tissue culture are
expensive to set up and are economical
only when very large numbers of plants are
produced.
Table 4.7 Advantages and disadvantages of asexual reproduction in crop plants.
52
4: Anatomy and physiology
The rhizomes of ginger, saffron and arrowroot can be cut into sections and, if each
section has at least one lateral bud, new plants can result. Bulbs, such as onions
and garlic, produce offset bulbs that are then separated and planted. Stem tubers
of Irish potato are used to produce new plants, and yam tubers can be made to
form buds that produce shoots.
4.5 Techniques used in plant propagation
Artificial propagation
The main methods of artificial propagation are:
• cuttings, for example, cocoa and guava
• layering, for example, rose and lime
• budding, for example, orange and avocado
• grafting, for example, mango
• tissue culture, for example, orchid and banana.
Cuttings
Cuttings are pieces of stem, root or leaf taken from a plant and given the right
conditions for growth. They contain cells capable of dividing and producing new
tissues. After cuttings have been taken from the parent plant, they need to be kept
in suitable conditions of humidity, light and temperature. High humidity prevents
cuttings from drying out, so they are usually kept in a propagator.
stem cuttings ▶
Types of stem cuttings (pieces of stem from which new plants will grow) are
listed in Table 4.8.
Type of stem cutting
Hardwood; taken from mature
plants with bark.
Semi-hardwood; taken where
bark is not fully developed.
Softwood or herbaceous; taken
from new (non-woody) growth.
Details of technique
Length 12 – 20 cm with four buds;
leaves removed; stem planted soon
after removal from plant.
Length 15 – 20 cm with four buds;
some leaves removed; must not be
allowed to dry out.
Length less than 10 cm; must not be
allowed to dry out; quick to root.
Examples
Grape, pomegranate
Cassava, sugar cane,
citrus (limes)
Sweet potato, oleander,
coleus
Table 4.8 Types of stem cuttings.
Figure 4.19 Soursop grown from stem
cuttings at the Caribbean Agricultural
Research and Development Institute
(CARDI), Grenada.
root cuttings ▶
Stem cuttings are usually taken from plants early in the morning when plant cells
are turgid and then wrapped in a moist tissue. Before planting in a propagator
with a suitable soil mixture, the base of each cutting is trimmed with a sharp knife
and the leaves removed or partially trimmed if necessary. The base is then dipped
in a rooting hormone that encourages the growth of roots. The soil is watered and
the propagator is placed in suitable conditions of light and temperature. The soil
and atmosphere around the cutting are kept moist.
Some stem cuttings, such as sugar cane, cassava and sweet potato, are planted
directly into the field plots as they produce roots easily.
Root cuttings are pieces of root from which new plants grow. They are taken
just before the rainy season, when parent plants are not actively growing. In the
propagation of breadfruit, lengths of root 10 –13 cm long are taken, a sloping cut
is made at the lower end, and the cutting is pushed into the rooting medium with
the top at soil level.
53
Section B: Crop production
Layering
adventitious roots ▶
tongue layering ▶
In layering, a young branch of a parent plant is encouraged to produce
adventitious roots by making an incision in the branch, bending it down and
covering it with soil. Two techniques are used: tongue layering and air layering.
Adventitious roots form from a section of the plant that is not underground.
Tongue layering is carried out on plants that have spreading branches close to
the ground.
• A suitable branch 5–8 mm thick is selected.
• The leaves are removed from the area to be layered.
• A diagonal cut is made into the middle of the stem on the underside of
the branch.
• The branch is held down in position on the ground by a wooden peg.
Roots form after 14–21 days. The newly layered plant can be cut from the parent
and transferred to a pot in a garden nursery.
a)
b)
parent
plant
the pegged area is covered
with humus and kept moist;
the stem can be cut from the
parent plant when the roots
are established
peg holds
branch at
soil level
soil level
small cut made at node
Figure 4.20 Tongue layering.
air layering ▶
roots develop
Figure 4.21 Budding of
soursop at CARDI.
In air layering, a young stem 7–8 mm thick is selected and leaves removed from
the area to be layered. The stem is cut into, and a portion of the bark removed
over an area 3–5 cm long. Rooting hormone is applied to the cut area, moist moss
is placed around it, and it is then wrapped up with polythene sheeting and tied
securely. Roots develop after 14–21 days. The newly layered plant is then cut
from the parent and transferred to a pot for nursery treatment.
Budding
budding, scion ▶
stock ▶
Budding is a form of grafting in which a single bud (the scion) from one plant is
inserted into the stem of another plant (the stock). The stock plant is rooted and
may be of the same species as the scion, or a related species.
To carry out patch budding you need to:
• remove leaves from the selected area of the stem of the stock plant
• lift a rectangular area of bark from the stem of the stock plant 20 –30 cm from
the tip
• choose a plump and healthy bud on the scion and carefully cut and lift off a
similar size of bark around it
• place the scion material on to the stock plant
• apply a fungicide to the area
• apply tape to the budded area leaving the bud exposed
• place the stock plant with its new bud in a cool area and water regularly.
54
4: Anatomy and physiology
The terminal bud of the stock plant can be removed to encourage the growth of
the scion. Sometimes an inverted T-shaped cut is made in the bark of the stock
plant and the bud is inserted into the cut. The scion is taped to the stock as before
to secure and protect the bud. This method is commonly used for propagating
citrus plants.
Grafting
grafting ▶
Practical activity:
Your teacher will demonstrate
budding and grafting techniques.
In pairs, practise budding and
grafting using a range of stock
plants and scions.
In grafting, the scion consists of a piece of stem with several buds on it. It is
inserted into the stem of the stock plant with the cut surface of the scion in direct
contact with the cut surface of the stock, so that the tissues of the two plants grow
together. For grafting to be successful, the scion and the stock have to be related:
either different varieties of the same species or belonging to closely related species.
Grafting is used to propagate mango, avocado and sapodilla.
There are two types of grafting.
• Side or veneer grafting: The scion is inserted into a cut made on the side of the
stem of the stock. The scion is 5–8 cm in length and fits snugly into the cut on
the stock. The two are securely taped together.
• Top or cleft grafting: The top of the stock plant is cut off, a wedge-shaped cut
is made and the scion is inserted. The two are taped together securely.
Figure 4.22 Cutting the top off the
stock plant.
Figure 4.23 Securing the scion in
the cleft.
Figure 4.24 Wrapping the grafted scion
with plastic and making it secure with tape.
Grafting solution at Mirabeau, Grenada
Sweet mango has always had the disadvantage that pests enjoy the flavour as much as people do.
Researchers at Mirabeau have discovered that sourness and resistance to pests are genetically linked, so they
use grafting to benefit from this information. Initially, sour mangos are grown from seed. Once these stock plants
are aged 4–5 months, a top or cleft graft is used to secure a sweet mango scion to the sour mango stock plant. Next,
the grafted area is wrapped in a plastic bag for three weeks, and secured with budding tape, to prevent the area from
drying out or being damaged by insects. Once the plastic is removed and the leaves have all hardened (another one to
two months) the plant can be sold to a farmer. The time from initial sour seed to sweet mango plant is about seven months,
although it will be another 10 –15 years before the mango tree bears fruit.
55
Section B: Crop production
Tissue culture
tissue culture ▶
Tissue culture is another artificial method of plant propagation. In this method,
a piece of plant tissue, such as stem, leaf or root, is cultured in a growing medium
of agar, nutrients and plant hormones to produce new plants. The technique
requires sterile, controlled conditions and results in large numbers of identical
plants, called clones. Orchid, banana and pineapple plants can be mass-produced
in this way.
4.6 Conditions necessary for germination
viable seed ▶
A viable seed is able to germinate and develop into a seedling. Seed viability is
usually expressed as a percentage. It refers to the total number of seeds expected
to germinate when 100 are sown. Seeds kept in sealed containers and cool storage
conditions maintain their viability over an extended period.
A germination test can determine the viability of any batch of seeds, especially
if they have been loosely stored for a long time. Most packets of seeds carry
information on the expected germination percentage, so that the purchaser or
farmer can decide how many seeds to plant and the density of planting.
germination ▶
Germination refers to the process in which the embryo inside the seed grows
and develops into a seedling, using food stored in the cotyledons or endosperm.
For germination to occur, seeds require three main conditions: water, oxygen and
a suitable temperature (see Table 4.9). In addition, most seeds germinate more
readily in darkness, although some seeds need light. In practice, many farmers
create semi-dark conditions, using palm leaves or saran netting to cover seedboxes
and seedbeds. The covering gives protection from seed-eating birds, but it needs
to be removed as soon as germination starts to prevent pale, weak seedlings.
Condition for germination
Air containing oxygen
Water
Suitable temperature
Function
• Oxygen is needed for respiration to release energy.
• The stored food in the seed is used to provide energy to make
new cells and tissues.
• Water causes the seeds to swell, splitting the testa and allowing
cells to take up water.
• Enzymes are activated so that starches are broken down to
sugars, proteins to amino acids and lipids to more soluble
substances.
• Food substances in solution are transported to the plumule and
radicle where growth is taking place.
• Warm temperatures speed up enzyme activity and growth.
• Optimum temperature range for germination of most seeds is
20 °C to 30 °C.
Table 4.9 The main conditions needed for germination.
scarification ▶
56
Some seeds with very hard seed coats may be scarified to speed up germination.
Scarification involves making scratches in the seed coat so that water can be
taken up more readily and germination can start. Farmers use techniques such as
scratching seed coats with a sharp and pointed instrument, blowing seeds against
a rough surface or rubbing the seeds on sandpaper.
4: Anatomy and physiology
Epigeal and hypogeal germination
epigeal germination ▶
hypogeal germination ▶
cotyledons
There are two main types of germination: epigeal germination and hypogeal
germination. In epigeal germination, the cotyledons rise above the ground as
the seedling grows. In hypogeal germination, the cotyledons remain below the
surface of the ground.
The two types of germination are compared in Table 4.10.
plumule
(develops into
the shoot)
radicle
(develops into
the root)
Figure 4.25 An embryo plant.
ITQ 10
Name the THREE main conditions
needed for germination to occur.
Use the embryo diagram alongside to identify the epicotyl, the region between the
plumule and the cotyledons, and the hypocotyl, the region between the radicle
and cotyledons, to understand how this seedling will germinate.
Epigeal germination
The radicle emerges and grows into the soil.
The hypocotyl elongates forming an arch.
The arched area appears above the ground.
Hypogeal germination
The radicle emerges and grows into the soil.
The epicotyl is elongated.
The hypocotyl is short and the upper part of the
hypocotyl is not curved down.
The hypocotyl straightens bringing the cotyledons The cotyledons remain below the ground.
above the ground; the plumule is protected
between the cotyledons.
The plumule grows, forming the first set of
The plumule grows, forming the first true leaves.
leaves.
The cotyledons wither and eventually fall off.
Cotyledons do not undergo photosynthesis.
Examples: kidney bean, cashew nut, tomato,
Examples: coconut, pigeon pea, maize,
cabbage
broad bean
Table 4.10 A comparison of epigeal and hypogeal germination.
true leaves
cotyledons
first leaves
cotyledon
remains
below ground
plumule
radicle
coleoptile
coleorhiza
coleorhiza
old seed coats
radicle emerges
and grows into
the soil
the coleoptile (plumule
sheath) grows upright
above the ground
plumule emerges
from the coleoptile
plumule grows
vigorously
Figure 4.26 Epigeal germination in kidney bean (left) and hypogeal germination in maize (right).
Germination of maize
The germination of monocot seeds, such as maize, is slightly different in that the
food store is in the endosperm. The cotyledon remains in the seed and absorbs
food from the food store, transferring it to the growing embryo. The radicle
emerges and grows into the soil. The plumule sheath (coleoptile) grows upright
and appears above the ground. The plumule emerges from the coleoptile, forming
the first set of true leaves. The cotyledon remains below the ground.
57
Section B: Crop production
Sowing seeds and seedling production
Practical activity:
Plant some seeds and grow
seedlings under different
conditions. For example, grow some
in the light, some in the dark, some
in a warm temperature, some in a
cold temperature and some without
water. Only vary one condition at
a time.
In crop farming, seedlings are produced using two major systems: container
systems and seedbed systems.
Container systems
Various containers can be used to raise seedlings: seedboxes, seedling trays,
plastic bags, plastic cups, discarded cans and plastic bottles. Seedboxes are most
commonly used for large-scale production of seedlings. Any containers should be
provided with holes for drainage before being filled with a potting soil mixture.
Commercially produced potting soil mixtures can be bought; however, a mixture
can be made up using local and available materials. Such a mixture would contain:
• 3 parts topsoil or clay
• 3 parts pen manure
• 1 part sharp sand
• 1 part rotted coffee hulls, bagasse, sawdust, coconut fibre bast or compost
• 500 g dolomitic limestone per cubic metre of topsoil.
Soil should be steam sterilised or treated with a soil sterilant (methyl bromide).
The constituents of the potting soil mixture ensure that it has a fine tilth, is rich
in plant nutrients, well aerated, retains adequate moisture and will drain freely.
Sterilisation will help to reduce the pests and weeds in the mixture. Ideally it will
have a pH of 6.0 to 6.5.
seedboxes ▶
Seedboxes, otherwise known as nursery boxes, are used for sowing seeds,
pricking-off (thinning-out) seedlings and raising young crop plants. A typical
seedbox is 35 cm long, 25 cm wide and 7 cm deep, and constructed of wooden
laths nailed together. At its base, there should be 5 mm wide slits for drainage.
25
cm
nails
35 c
m
7 cm
slits for drainage
laths 1 cm thick
Figure 4.27 A typical seedbox.
seedling trays ▶
58
Seedling trays are commercially made and are now more widely used than
seedboxes. The trays are made of expanded polystyrene (Styrotex), 75 cm long,
35 cm wide and 7 cm deep, divided into compartments. They can be filled with
potting soil mixture. One seed is usually sown in each compartment so thinningout of seedlings is not required. The seedlings become well rooted and are easily
lifted out for transplanting. As with the seedboxes, trays can be re-used for several
batches of seedlings.
4: Anatomy and physiology
The advantages of container systems are that:
• the seedlings are cared for in a nursery
• it is more convenient to handle and transport the seedlings
• the seedlings become well rooted in the potting soil medium
• the development of the seedlings is more vigorous as they have more space,
root room and nutrients
• each seedling can be transplanted with a ball of soil (pillon) around the roots
• most containers can be re-used for further seedling production.
Figure 4.28 Seedlings in a greenhouse.
Practical activity:
Choose an easy crop to grow from
seed, for example, tomatoes or bell
peppers. Germinate the seeds in
containers. Once the seedlings are
well established, sell locally.
Figure 4.29 Seedbed.
Seedbeds
Seedbeds are useful for the production of seedlings for field crops requiring a
large number of plants, such as rice, cabbage, tomato and sweet pepper. They
are established close to the field plot, making it easy to transplant the seedlings,
and saving time, labour and transportation costs. The nature of the seedbeds
depends on the crop. For example, a seedbed for cabbage seedlings needs to be
cambered and well drained, but for rice seedlings the area should be bunded
(have embankments) to retain water.
A typical seedbed is 3 m long and 1 m wide, cambered for surface drainage and
surrounded by box drains for sub-surface drainage. The soil should be manured
and have a fine tilth.
To prepare a seedbed:
• brushcut the area and clear it of grass and bush
• plough with a hand tractor or garden fork
• refine the soil to a fine tilth using a rotovator, hoe or rake
• dig box drains
• level the soil and camber
• add pen or compost manure to a depth of 2–4 cm
• add NPK fertiliser (10:15:10) at the rate of 30 g per square metre (30 g/m2) if
required. This may not be needed if the seeds are following a legume such as
pigeon pea
• mix manure and fertiliser with the top 4–8 cm of soil
• level the soil and remove large pieces of organic matter with a rake
• keep an eye on the young plants. If there is evidence that pests or fungus are
present, spray with insecticide or fungicide.
Methods of sowing seeds
Methods of sowing depend on the container, the number to be planted and the
nature of the seeds.
• Seeds may be scattered or broadcast by hand (distribution should be even),
then covered with a thin layer of potting soil.
• Seeds may be sown in shallow drills made by a dibber in the soil surface. The
soil should cover the seed and protect it from birds.
• Very tiny seeds can be mixed with water or sand before sowing. For example,
tobacco seeds are mixed with water in a watering can and applied to the
soil as a fine spray. Celery seeds may be mixed with sand and then either
broadcast or sown in drills.
• If seedling trays are used, seeds are planted singly in the compartments. A
small hole 1–2 cm deep is made with a dibber, the seed is placed inside and
then covered with potting soil.
59
Section B: Crop production
The nursery
nursery ▶
A nursery is where young plants are housed while being reared for transplanting
into field plots.
The main features of a nursery should include:
• a steel or wooden construction so that it is sturdy
• a graded concrete floor for efficient drainage
• a roof covered with transparent polythene, so that light can enter but the
seedlings are protected from rain
• saran netting placed on the windward side to protect seedlings from
wind damage
• concrete stands for seedboxes, seedling trays and containers.
Figure 4.30 Pepper nursery.
Thinning-out
Thinning-out gives each seedling more space for growth. It also reduces
competition for light, water and nutrients, so that growth is more vigorous. If
seedlings are spaced, they can be lifted out with a pillon (ball of soil around the
roots) when transplanting. In thinning-out, or pricking-off, seedlings are carefully
removed from their original container or seedbed and transferred to another
prepared container. The newly thinned-out seedlings need to be protected from
direct sunlight and rain.
1. water soil in seedbox
2. make holes with
the dibber
3. carefully select
a seedling
4. gently position soil
around the roots
5. water the seedlings
6. place under the shade of
a tree
Figure 4.31 Pricking-off or thinning-out seedlings.
Looking after seedlings
In the nursery, seedlings need to be watered regularly using a watering can with
a fine rose. Weeds should be removed by uprooting or using a dibber, and the
soil surface broken up to prevent compaction and to increase aeration. Fine pen
manure or liquid manure can be applied to the soil surface after it has been broken
up. To control pests and diseases, seedlings should be inspected and treated with
insecticides if necessary. Seedlings may be attacked by a fungus that causes a
disease called damping off. This weakens the stems allowing the seedlings to
topple over. The disease can be controlled by aerating the soil, reducing the
watering and, if necessary, applying a fungicide to seedlings and soil.
60
4: Anatomy and physiology
transplanting ▶
hardening ▶
Transplanting
Before transplanting, seedlings should be exposed gradually to sunlight over a
period of 7–10 days. This is called hardening and helps to strengthen the young
plants so that they can withstand full sunlight by the time they are transferred to
field plots.
Transplanting is carried out early in the morning, late in the evening or when it
is cloudy to:
• protect the seedlings from the sun
• reduce wilting.
1. water seedlings
in seedbox
2. remove seedling
with a trowel
3. position in
the soil
4. gently firm
the soil
The field plot is prepared by digging holes for the seedlings, using the recommended
spacing, and placing pen manure or compost into each hole. The soil of the
containers is watered and the seedlings are removed, each with some soil around
the roots. Each seedling is placed in its prepared hole, ensuring that it is not
planted too deeply, and the soil is gently firmed around it so that the seedling stays
upright. Seedlings should be watered after transplanting: this reduces wilting and
settles the loose soil, bringing soil particles in closer contact with roots.
Stages of plant growth
During the life of a plant, there are two main stages of growth: the vegetative
stage and the reproductive stage.
vegetative stage ▶
5. water the
transplanted
seedlings
Figure 4.32 Transplanting seedlings.
reproductive stage ▶
The vegetative stage involves:
• the growth of the zygote into the embryo, the embryo into the seedling, and
the seedling into a mature plant
• the rapid increase in cell division, cell enlargement and differentiation into
specialised tissues and functions
• the rapid increase in plant size and weight
• a large amount of branching and leaf development.
In the reproductive stage:
• the general increase in plant size slows down and the development of new
branches and leaves occurs
• flowers, fruits and seeds are produced, continually or seasonally, until the
plant dies.
These stages are illustrated in Figure 4.33.
maturity
vegetative stage
reproductive stage
seedling
zygote
embryo
young
immature
plant
mature
plant
flowering
stage and seed
production
dead plant
Figure 4.33 The stages of plant growth.
61
Section B: Crop production
Revision map
Flat, thin
structures
adapted for
photosynthesis
Stomata
for exchange
of gases
Cuttings
Budding
Upper and
lower
epidermis
Grafting
Plant
propagation
techniques
Leaves
Layering
Day length
(photoperiodism)
Monocots
Plants
respond to
environmental
factors
Internal and
external
structure
of plants
Anatomy and
physiology
Light
(phototropism)
Dicots
Roots
Pollination and
fertilisation needed
to produce fruits
and seeds
Good
drainage
Well-fertilised
Free from
weeds and
pests
Sexually,
through
pollination
Types of plant
reproduction
Growing
conditions
Sexual and
asexual
reproduction
Seedbed
preparation
Male
reproductive
structures are
the stamens
Seed
germination
Soil should
have a fine
tilth
Epigeal –
cotyledons rise
above the
ground
Filament bearing
anthers where pollen
grains (containing male
gametes)
are formed
Female
reproductive
structure are
the carpels
Hypogeal –
cotyledons
remain
underground
Style
Stigma
62
Asexually by
natural and
artificial
methods
Ovary in which
the ovules
(containing female
gametes) develop
4: Anatomy and physiology
Examination-style questions
Multiple-choice questions
Write down the number of the question followed by the letter of the correct answer.
1. Which of the following is NOT a characteristic of monocots?
A Seeds with one cotyledon
B Long thin leaves with parallel veins
C Cambium present in stem and root
D Flower parts in threes
2. Which of the following plants is a dicot?
A Corn
B Bamboo
C Sugar cane
D Cabbage
3. Which type of root system does a mango plant have?
A Tap
B Fibrous
C Adventitious
D Aerial
4. Monocot and dicot leaves both have:
A parallel veins
B a definite midrib
C palisade mesophyll
D stomata.
5. Which of the following is NOT a feature of insect-pollinated
flowers?
A Long feathery stigmas
B Brightly coloured petals
C Sticky pollen
D Nectar
6. The process by which plants lose water in the form of water
vapour is called:
A translocation
B transpiration
C photosynthesis
D absorption.
Short-answer and essay-type questions
7. (a) (i) Explain the meaning of ‘pollination’.
(ii) List TWO agents of pollination.
(b) Describe the major features of insect-pollinated flowers.
(c) State the importance of pollination in agriculture.
8. (a) (i) Explain the meaning of ‘asexual reproduction’.
(ii)
List the TWO main methods of asexual reproduction
and give an example of each.
(b) Complete the table below.
Vegetative organs
Suckers
Bulbs
Corms
Rhizomes
Two examples
9. (a) (i) What is the meaning of ‘budding’?
(ii) Name TWO examples of budded plants.
(b) (i) What materials are required for budding citrus plants?
(ii) Describe, step by step, the budding procedure.
(c) (i) Differentiate between scion and stock.
(ii) What is the purpose of budding tape?
10. (a) (i)Explain the meaning of ‘grafting’, naming TWO
examples of grafted plants.
(ii)
List TWO techniques of grafting that are commonly
used.
(b)
Describe the technique of grafting a mango plant, using the
following headings:
(i) Materials required
(ii) Procedure (step by step).
11. (a) What is the meaning of ‘germination’?
(b)
Using appropriate examples, explain the difference between
(i) epigeal germination and (ii) hypogeal germination.
(c)
Using diagrams, describe fully the stages of germination in
the kidney bean.
12. (a) State the meaning of:
(i) photosynthesis
(ii) respiration.
(b)
Explain this statement: ‘Respiration is the opposite of
photosynthesis.’
(c)
State the importance of photosynthesis and respiration to
plant growth.
13. (a) Describe the differences between monocot and dicot leaves.
(b)
Explain what is meant by photosynthesis and name the
essential requirements for the process.
(c)
State the importance of photosynthesis to the plant and for
the farmer in terms of crop production.
63
Section B: Crop production
5
Environmental
factors affecting
crop growth
By the end of this unit you should be able to:
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
Concept map
Effects of
environmental factors
on plant growth
and development
Aerial factors
Climate
Temperature
Sunlight
Rainfall
Wind
Relative
humidity
Soil factors
Soil type
Soil fertility
Environmental factors affecting crop growth
Soil components
Inorganic matter
Volcanic activity
Organic matter
Effects of soil
organisms
Effects of
human activity
Process of formation
Weathering
Mechanical
Chemical
Biological
Soil profile
Horizons
64
discuss the effects of environmental factors on plant growth and development
describe the process of soil formation
explain the importance of a soil profile
describe the major components of soil
describe the physical and chemical properties of soil
describe the availability of soil water for crop use
explain the causes and effects of soil erosion
state the importance of major nutrients used in crop production
explain the factors affecting soil fertility
explain how soil fertility can be maintained
explain soil and water conservation methods.
Soil properties
Soil nutrients
Soil erosion
Physical
Carbon
Cropping
systems
Texture
Structure
Soil temperature
Soil organisms
Nitrogen
Minor
nutrients
Chemical
Soil nutrients
Particle-nutrient
relationship
Leaching
Soil pH
Soil water
Soil air
Soil
fertility
Factors
Parent material
Land management
Fertilisers
Inorganic
Organic
Fertiliser ratio
Soil amendments
Cultural
practices
Types of
erosion
Causes of
erosion
Water
Wind
Burning
Animals
Soil and water
conservation
methods
5: Environmental factors affecting crop growth
5.1 Effects of environmental factors on plant
growth and development
growth ▶
development ▶
Practical activity:
Set up or build and use a rain
gauge. Record measurements for
a month, then use the data to
practise drawing graphs.
Growth is a characteristic of all living things. It can be defined as an increase in
the size of a plant. Development refers to changes in form and function that
occur during the different stages of growth. Plant growth and development are
affected by environmental factors, which should be taken into consideration
before crop production is undertaken.
Aerial and soil factors
Aerial environmental factors are those that come from the air and atmosphere,
such as climate, temperature, sunlight, rainfall, wind and relative humidity. Soil
type and fertility are the remaining factors. It is vital that appropriate crops are
chosen specifically to match the aerial and soil factors so that the plants will thrive.
Climate
rainfall ▶
Rainfall provides water for essential plant processes. Excessive rainfall results
in waterlogged soil, which slows plant growth. An absence of rain also damages
growth. Plants may wilt and die without enough water. When considering which
crops to grow, thought must be given to drainage and irrigation.
temperature ▶
Temperature controls the rate of metabolic activities in plants. Effective growth
is promoted by cool to moderate temperatures. If the temperature is too high,
metabolic activities in plants are increased and the food energy that is left for
growth and development is reduced. If the temperature is too low, the metabolic
rate slows and growth is reduced. In the Caribbean, temperatures do not vary
greatly, but shade should be provided for young seedlings in warm weather.
sunlight ▶
Sunlight is essential for photosynthesis, which results in food for growth and
development. If plants are grown in the dark, they produce long, slender stems
and unexpanded leaves. They lack the green pigment chlorophyll, so cannot carry
out photosynthesis and die when their food reserves are used up. Such plants are
referred to as etiolated and the condition is called etiolation.
etiolation ▶
The direction of the light affects the growth of shoots (phototropism). Also,
the length of the day affects vegetative growth and flowering in some plants
(photoperiodism).
Sunlight also affects transpiration. Plants under shade lose less water through
transpiration than those in sunlight. As a consequence, these plants produce
leaves that are well expanded.
wind ▶
Wind can take fine particles of dirt and dust and can hold them in the air
(suspension), or roll them over an area (creep). Both suspension and creep can
move the particles over long distances.
relative humidity ▶
Humidity is a measure of the water content of the atmosphere. Relative
humidity affects soils as the moisture content of the air will determine how wet
or dry the surface of the soil is. In arid areas, where humidity is relatively low,
there is an increased risk of soil erosion by wind.
65
Section B: Crop production
Caribbean climate
Rainfall
In the wet season, heavy rain results in waterlogged soils,
which prevents tillage and affects the soil organisms.
Flooding occurs in low-lying areas and there is soil erosion,
with nutrient leaching and crop and livestock damage.
In the dry season, there is a lack of water so crops need
to be irrigated. The flat islands of Antigua and Barbados
have low mean annual rainfalls and prolonged periods
of drought. These dry periods harm plants and reduce
productivity.
Temperature
Most Caribbean countries are between 1 °N of the Equator
and the Tropic of Cancer so the climate is tropical with an
average range of temperature between 22 °C and 34 °C
(suitable for year-round agriculture). The altitude of the
mountains is not high enough to cool the temperatures
substantially.
Wind
The Caribbean consists mainly of small island states. It is
windswept and cooled by sea breezes and the northeast
trade winds. The winds help to maintain a standard
temperature across each island. However, the Caribbean is
prone to hurricanes with high winds and torrential rains.
Humidity
Humidity varies according to the seasons. In the wet
season, the humidity is high and in the dry season it
is low. When humidity is high, fungal diseases
spread, affecting more crops.
Soil fertility
Soil fertility is vital for plants to obtain the necessary nutrients for growth. Soils
with low fertility restrict growth and development, resulting in low yields. Soil
fertility can be managed in a number of ways (see Section 5.9).
5.2 Process of soil formation
Soil on the Earth varies in composition, type and thickness at different places.
weathering ▶
Weathering is the decomposition of the Earth’s rocks. Soil is formed through
weathering. Soil is a mixture of the parent rock, organic material (humus), air
and water. It provides an environment for the growth of plants as well as a habitat
for vast numbers of soil organisms. Soil may be found overlying the parent rock
or it may be transported by natural forces, such as water, wind and glacial action
and deposited at other locations. This process is called erosion.
bedrock ▶
Weathering involves the breakdown of bedrock (unweathered rock) into smaller
particles. The type of soil formed depends on the parent material, or bedrock.
Where the parent material is shale, then a clay soil is produced. Where the parent
material is sandstone, sandy soils are formed.
Soils formed in hilly or mountainous areas are shallow. Sometimes in erosive
regions, soil development occurs only in the foothills and valleys with very little
soil forming higher up. This is due to water and glacial action.
Figure 5.1 Earthworms in the soil.
66
There are three forms of weathering:
• mechanical (or physical)
• chemical
• biological.
5: Environmental factors affecting crop growth
Mechanical (or physical) weathering
physical weathering ▶
Physical weathering is the breakdown of rocks by forces applied to rock, either
from within or from the outside, causing the rock to break down. In cold regions,
freeze-thaw weathering is most common. In this type of weathering, water in
cracks in rocks expands as it freezes. The expansion results in the cracks widening
and the rock splitting apart.
In the Caribbean, weathering regularly occurs when moving water in rivers
or waves at the coast causes rocks to collide, disintegrate and get worn down
into smaller pebbles and eventually mineral particles. In very dry regions, wind
containing sand particles has an abrasive action and wears away the surface of
rocks. The particles of rock can be carried to other sites where they are deposited.
In locations with high temperatures, the sun heats up the surface of rocks causing
them to expand. At night, when the temperature drops, the rock cools and
contracts. Over time, the surface layers break away. This is also called onion-skin
weathering.
1. Rock surface
heats up and
expands during
the hot day.
2. Rock surface
cools and
contracts during
the cold night.
3. Fractures form
on the surface
due to repeated
expansion and
contraction.
4. Outer layers
shatter and
pieces of rock
break off.
Figure 5.2 Onion-skin weathering.
Chemical weathering
chemical weathering ▶
Chemical weathering is weathering that alters the chemical nature of the rock.
The main factors that cause chemical weathering are water, oxygen and carbon
dioxide.
Water
Rocks are made of materials that have different levels of solubility. For example,
sodium chloride (common salt) is soluble and is only found as a solid (rock salt) in
very dry areas. Other rocks that are soluble, but less so, include gypsum (calcium
sulphate) and limestone (calcium carbonate). Silica, a component of sand, is only
slightly soluble in water.
Water can change the minerals in rocks. If water is added to some soil minerals, it
causes chemical changes and new minerals are formed. For example, potassium
may be removed from the rock known as feldspar, leaving aluminium and silicon.
These can then re-crystallise to form clay.
oxidation ▶
Oxygen and carbon dioxide
Oxidation occurs when minerals in rock combine with atmospheric oxygen or
the oxygen dissolved in rainwater. The minerals are converted to oxides, which
are more likely to break down or undergo weathering. For example, when water
combines with the iron-containing rock, olivine, ferrous oxide is released. The
ferrous oxide becomes oxidised by oxygen in the atmosphere to ferric oxide,
known as haematite.
When carbon dioxide in air dissolves in rainwater, carbonic acid is formed. This
is a weak inorganic acid. As rainwater filters through rock containing carbonate,
such as limestone, the minerals in the rock dissolve and the rock breaks up.
67
Section B: Crop production
In most humid regions, other dilute inorganic acids (such as nitric acid and
sulphuric acid) and some organic acids are also important in weathering rocks.
Biological weathering
biological weathering ▶
Biological weathering refers to the disintegration of rocks and the formation of
soil through the activities of living organisms.
If there are cracks in a rock, some soil will gather. If a seed germinates in this
soil, its growing roots exert pressure and eventually the rock splits. Animals that
tunnel into the soil, such as worms, ants and moles, contribute to weathering by
bringing new material to the surface where it is exposed to rainwater and the
atmosphere.
ITQ 1
(a) Describe how physical
weathering occurs.
(b) Explain how biological
weathering disintegrates rocks.
Plants rot and are decomposed by micro-organisms in the soil. In this process,
organic acids called humic acids are released into the soil and break down rock
minerals. The plant roots also release carbon dioxide into the soil and carbon
dioxide breaks down carbonates.
5.3 The importance of a soil profile
soil profile ▶
A soil profile is a vertical section dug down through the soil showing the natural
sequence of horizontal layers in the soil. It can be revealed by digging a rectangular
pit so that one wall of the pit exposes the colours and textures of the different
layers. Alternatively, a soil auger can be used to remove a core of soil and the
different layers can be identified. Figure 5.3 shows a soil auger in use.
Soil horizons
soil horizon ▶
Each layer, or soil horizon, has different physical and chemical properties. The
development of soil layers is affected by the topography of the land, soil texture,
drainage and soil erosion.
In a typical, undisturbed, well-drained forest soil, at least four major horizons can
be recognised. Horizons are named O, A, B and C and may contain one or more
sub-horizon.
Name of horizon
Characteristic features
O horizon
Organic or litter
layer
A horizon
Zone of leaching or
eluviation
B horizon
Zone of
accumulation or
illuviation
• Formed on the surface.
• Consists of plant and animal material at different
stages of decomposition.
• Consists of a mixture of humus and mineral soil.
• Normally dark brown, dark grey or blackish in colour
due to leaching of materials from the O horizon.
• Usually lighter in colour than the A horizon.
• Leached clay, iron and aluminium oxides, calcium
carbonate, sulphates and other salts accumulate in
this horizon.
• An impervious layer called ‘hardpan’ may develop.
• No biological activity or soil formation takes place.
• May or may not be the same material from which
horizons A and B were formed.
C horizon
Parent material
Table 5.1 Horizons and their characteristic features.
68
Photograph of
horizons
5: Environmental factors affecting crop growth
samples are laid out
on the ground in the
order in which they
are removed from the
augur hole
1
2
3
4
5
6
1
2
For the farmer, the soil profile is relevant so that he or she can decide what land
preparation is needed before planting crops. During ploughing, the furrow slice or
topsoil is cut and inverted by the ploughshare. Depending on the thickness of
horizons O, A and B, this slice may include horizon O and part of horizon A, or
horizon O, horizon A and part of horizon B.
The area beneath the furrow slice is referred to as the subsoil. If there is a hardpan
or impervious layer, resulting from the accumulation and compaction of leached
deposits, then the subsoil may need to be broken up with a subsoiler.
3
4
5
furrow slice
(topsoil)
6
Figure 5.3 Soil horizons applied to crop
management.
subsoil
ITQ 2
parent
material
Explain which horizons are affected
when the land is ploughed.
O1
O2
A1
A2
A3
O
organic matter, leaf mould, forest litter
A
zone of leaching or eluviation
B
zone of accumulation or illuviation: a hardpan may develop
C
parent material: zone devoid of biological activities
B1
B2
B3
C
Figure 5.4 A typical soil profile.
Practical activities:
1. Examine a soil profile and
measure the depth of the
different horizons. Draw a
diagram showing the different
soil horizons.
2. Use a soil auger to determine
the characteristics of a soil
profile.
Depending on the soil profile, the farmer will decide how deep to plough, what
equipment to select for tillage and what crops to grow (shallow-rooted or deeprooted).
5.4 The major components of soil
Soil is made up of:
• inorganic matter (mineral particles)
• organic matter
• water
• air.
Latosols, Grenada
Most soils in the Caribbean are latosols. Latosols form when rainfall is greater
than evaporation and there is rapid leaching of dissolved minerals. These soils
support dense, tropical rainforest. The organic layer (O horizon) of leaves
and litter is usually less than 25 mm deep. Because of high temperatures and
humidity, organic matter decomposes very quickly. The A horizon is usually
300 mm deep and a dark brown to reddish colour. The clay content makes
the soil sticky.
Figure 5.5
Latosol in Grenada.
69
Section B: Crop production
mineral matter
organic matter
The mineral particles and the organic matter (about 50% of the soil) are referred
to as solids. The water and air, which make up the remaining 50%, are referred
to as pore space. By volume, the percentage that is solid is made up of approximately
45% mineral particles and 5% organic matter. The percentage that is pore space
is roughly divided into 25% water and 25% air, but both can vary according to
weather conditions.
Inorganic matter
water
air
The mineral component of soil is derived from the weathering of rocks. It is
porous and consists of stones, gravel, sand, silt and clay. These components vary
in size and composition, as shown in Table 5.2.
Component
Figure 5.6 The major components of soil.
Size of particles (from
larger to smaller)
Stone and gravel remnants Very coarse > 2.0 mm
Sand
Coarse sand 2.0 – 0.2 mm
Fine sand 0.2 – 0.02 mm
Silt
Fine 0.02 – 0.002 mm
Clay
Very fine < 0.002 mm
Characteristics
Fragments are remnants of massive rocks.
Primary minerals, such as quartz, having
the same composition as the parent rock.
Primary and secondary minerals, such as
oxides of iron and aluminium developed
through weathering.
Colloidal in nature; secondary minerals
are formed through weathering.
Table 5.2 The mineral components of soil.
Practical activity:
Shake up 100 g of soil in 500 cm3
of water in a large jam jar or
measuring cylinder. Allow the
contents to settle.
Describe and identify the different
components. Organic matter will
float and different-sized particles
will settle in layers according to
their sizes.
The coarser mineral fragments may be bound into lumps, clods or aggregates by
humus and colloidal clay particles. These aggregates are porous and contain pore
spaces for soil air and soil water.
Volcanic activity and soil formation
Volcanic activity on the Caribbean islands generates igneous rocks. These rocks
weather into volcanic soils. Volcanic soils are found on Grenada, St Vincent,
St Lucia, Dominica and Montserrat. The soil on the slopes and in the valleys of the
volcanic cones is derived from the lava thrown out when an eruption occurred.
Volcanic soils are dark grey and have a granular structure. They are porous
and high in sulphur, phosphorus and potassium. Volcanic ash is also emitted in
volcanic activity, and it settles in a fluffy, greyish layer. The ash is incorporated
into the topsoil by further weathering and cultivation by farmers. It is not easy to
see decomposed organic matter in such soils because of their colour.
Organic matter
organic matter ▶
Organic matter consists of fresh or decaying plant and animal residues and
humus. Humus is the end product of the decomposition of organic matter by
micro-organisms. It is black or dark brown. In the tropics and sub-tropics, organic
matter is broken down rapidly to humus by soil micro-organisms.
Although the organic content of soils is small (3% to 5%), it improves the soil,
which aids crop growth and production in the following ways:
• it loosens clay particles, serving as a ‘granulator’
• it binds mineral particles, especially sand, into aggregates
• it reduces the cohesion (sticking together) of clay and silt particles
• it increases the water-holding capacity of sandy soils
• it supplies mineral ions, such as nitrates, sulphates and phosphates
• it is the source of energy for the soil micro-organisms
• it increases the productive capacity of soils.
70
5: Environmental factors affecting crop growth
Effects of soil organisms on soil
Soil micro-organisms, such as bacteria and fungi, break down organic matter into
humus.
vermiculture ▶
List FOUR factors that affect soil
formation.
Vermiculture is the cultivation of earthworms (see Figure 5.1). It contributes to
soil formation and soil fertility in the following ways.
• Earthworms make tunnels that allow air down into the soil and also help the
soil drain.
• Earthworms make their tunnels by swallowing soil, so that the organic matter
is digested and the mineral particles pass out of the gut back into the soil. In
some species, egested (excreted) soil is deposited on the surface as a ‘worm
cast’ and consists of finely ground particles. This process mixes up layers of soil.
• Earthworms pull leaves into their tunnels for food. This increases the organic
content of the soil and contributes to mixing.
Practical activities:
Other burrowing organisms, such as insects, insect larvae, slugs, spiders and
woodlice, keep soil loose and aerated. Their faeces contribute to the organic
matter and provide food for micro-organisms.
ITQ 3
1. Make a poster to show
how certain soil types are
associated with their parent
material.
2. Make a collection of soils
formed by different soilforming activities. Examine
the soils, noting their
characteristics. Suggested
types are volcanic soil, a good
agricultural soil, a soil that has
been chemically weathered (a
limestone soil) and a soil that
still shows evidence of physical
weathering.
Plant roots bind soil particles together and also create channels for the cycling of
nutrients within the soil.
Effect of human activities on soil
Several human activities affect the formation and fertility of soil.
• Land clearing interrupts the accumulation of organic matter.
• Grading and levelling of land removes the topsoil and often the sub-surface
layers as well.
• Mining, quarrying and soil removal upset the activity of soil-organisms and
soil formation.
• Ploughing disturbs soil layers but it does break up rock fragments.
5.5 The physical and chemical properties of
major soil types
The classification of soil types is based on the quantities of different-sized mineral
particles and the soil-forming processes. It makes sense that:
• a clayey soil will contain a high proportion of clay particles
• a silty soil will be made mainly of silt particles
• a sandy soil will have more sand particles than other particles
• a loam soil will contain roughly equal amounts of sand, silt and clay particles.
alluvial soils ▶
colluvial soils ▶
ITQ 4
State the difference between an
alluvial and a colluvial soil.
saline soils ▶
There are also other differences between soils. For example:
• gravelly soils contain lots of particles larger than 2 mm in diameter
• alluvial soils are formed through the action of running water, which breaks
up rocks, transports mineral particles and then deposits them at a distance
from the parent rock
• colluvial soils have moved down the slope, or accumulated at the bottom of
a hill as a result of gravity; they are often gravelly
• volcanic soils are formed from lava and volcanic ash
• peaty soils are found in marshy areas and are formed by the accumulation
and partial decomposition of organic matter
• saline soils are found in coastal areas affected by seawater and contain high
concentrations of salt; these are of little value in crop production.
71
Section B: Crop production
Physical properties of soil
soil texture ▶
Practical activity:
Use the ‘feel’ method and the
moulding technique to identify the
texture of samples of soil.
Soil texture
Soil texture refers to the fineness or coarseness of the soil. It is determined by
the proportion of different-sized mineral particles present (see Figure 5.7). For the
farmer, soil texture is related to the workability of the soil and how easy it is to
plough. Some soils are ‘light’ as they are easy to till (sandy soils). Some soils are
‘heavy’ (clay soils) and other soils are ‘intermediate’ (loam soils).
Soil texture can be determined by three main techniques, which are summarised
in Table 5.3.
Technique
‘Feel’ method
Method
A small amount of soil is rubbed
between the thumb and fingers.
Moulding
The soil sample is made wet and
then kneaded.
Mechanical analysis (carried out
in the laboratory)
This method involves sieving,
sedimentation and calculation.
Results
Soils with a large amount of sand feel gritty.
Soils with a high proportion of silt or clay feel smooth and silky.
Clay soils develop continuous, cylindrical ribbons when moulded.
Silty soils are moderately sticky and the ribbons break up into small pieces.
Sandy soils do not form ribbons.
The results of these techniques can be used to check the feel and moulding
methods and enable the soil type to be determined more accurately.
Table 5.3 Techniques for determining soil texture.
100% 0
clay
90
10
80
20
70
30
40
en
rc
pe
30
60
clay loam
sandy clay loam
20
10
loam
loa
sand
0
100%
sand
my
90
ilt
40
50
silty clay
sandy
clay
sandy loam
silty clay
loam
70
80
silt loam
90
san
silt
d
80
ts
50
en
rc
tc
lay
60
pe
clay
70
60
50
40
per cent sand
30
20
10
100%
silt
0
Figure 5.7 Soil textural classes based on particle-size distribution percentages.
Soil texture is important to the farmer because it affects the:
• holding capacity of air and water in the soil
• ease and rapidity of drainage
• total surface area of mineral particles available for chemical reactions to
take place
• workability of the soil (whether it is ‘light’ or ‘heavy’)
• ease with which roots can penetrate
• way in which crops respond to fertilisers.
Soil structure
soil structure ▶
72
Soil structure refers to the arrangement of the various particles, cemented
together into clusters (aggregates) that create a network of cracks and pores in
the soil. Although aggregates may be made up of similar types of particles, they
generally differ in size, shape, particle composition and arrangement and stability.
Aggregates contain pore spaces between their particles (intra-pore spaces) and
there are spaces between adjacent aggregates (inter-pore spaces).
5: Environmental factors affecting crop growth
ITQ 5
Describe how soil texture can be
determined by the farmer in the
field.
The aggregates may form:
• lumps with a diameter greater than 10 mm
• crumbs with a diameter from 5 to 10 mm
• granules with a diameter of less than 5 mm.
Aggregates are classified into four major types (see Table 5.4).
Type
Laminar
Prism-like or
columnar
Blocky or cubical
Spheroidal or
rounded
Characteristics
Thin, flat, horizontal, leaf-like plates.
Pores and cracks are horizontal.
Tops of aggregates are level (prism-like) or rounded (columnar).
Faces are smooth and flat.
Cracks and pores are vertical and prominent.
Surfaces are flat or rounded and fit snugly when wet.
Horizontal and vertical cracks and pores are well developed.
Surfaces are rounded but do not fit snugly when wet, leaving pores
between them.
Occurrence
Found in virgin soils, leached soils (subsoils) and clay soils
(kaolinite).
Found in clay loams and clays.
Found in heavy subsoils (clays).
Found in surface soils, rich in organic matter; aggregates
with a granular structure are porous and those with a crumb
structure are very porous.
Table 5.4 Major types of aggregates and their characteristics.
Factors affecting aggregate formation
The following factors affect the ease with which aggregates form.
• Climate: The climate can wet, dry, freeze and thaw.
• Activities of soil organisms: Fungal mycelia cement the soil particles together.
Earthworms, termites, beetles and slugs burrow and mix soil particles. Microorganisms decompose organic matter and form humus.
• Organic matter accumulation and decay: Humus has a binding effect.
• Activities of plant roots: Roots penetrate, permeate, produce gum exudates
and decay.
• Tillage operations: Farmers carry out ploughing, rotovating, manuring and
liming.
tilth ▶
In practical farming, farmers recognise the importance of preparing and
maintaining the soil in a suitable physical condition for the cultivation of crops.
Tillage will break up and mix the soil to produce stable aggregates and a crumb
structure called the tilth. A good tilth provides adequate aeration, moisture,
drainage and root-room for the crop.
Practical activities:
1. Using a sandy soil, a clay soil and a loam soil, set up an experiment to find out which soil drains the quickest and which soil holds
most water. Make your experiment quantitative by using measured volumes of soil and water, and by allowing a specified time for
the water to drain through.
2. Soil contains organic and mineral matter. The organic matter consists of the dead and decaying remains of plants and animals. The
mineral matter consists of the weathered rock particles. Follow the instructions to determine the quantity of each in the soil.
(a) Weigh 10 g of soil (M1) in a heatproof container.
(b) Heat the container to 105 °C for 2 hours to remove the moisture from the sample.
(c) Weigh the sample again (M2) before heating it to 400 °C to burn off the organic matter. A propane torch (or high-temperature
oven such as a kiln) can be used to do this.
(d) When the soil has cooled, re-weigh the sample (M3).
The quantity of organic matter = M3 – M2
The quantity of water in the sample = M1 – M2
The quantity of mineral matter = M3
73
Section B: Crop production
Soil temperature and soil organisms
In the Caribbean, temperature on the soil surface ranges from 23 °C to 30 °C.
Within the top 15 cm of soil (the furrow slice), temperatures between 28 °C and
30 °C are the most favourable for the soil organisms, biochemical processes and
soil formation.
Soil temperature is influenced by sunlight, vegetative cover, soil cover (both
natural and artificial), soil moisture and organic matter content. All these factors,
with the exception of direct sunlight, lower the soil temperature. Soils that lack
vegetative cover and that have little organic matter, lose moisture rapidly when
exposed to direct sunlight. Consequently, the soil temperature will rise.
macro-organisms ▶
Soil temperature affects:
• soil macro-organisms, such as earthworms, which burrow more actively
when it is warm
• soil microbial activity, which increases in warm conditions and decreases in
cold conditions
• seedling roots, which are destroyed by high soil temperatures as plant cells
dehydrate through evapotranspiration
• seed germination, which is more rapid in warm temperatures
• soil caking and crusting, which occurs as a result of high soil temperatures,
direct sunlight and rapid loss of moisture.
Farmers can lower the soil temperature by mulching, cover cropping, intercropping,
irrigating, improving soil cover and incorporating organic matter into the soil.
Chemical properties of soil
Soil nutrients
Plants require 17 essential nutrient elements for their growth and development.
These are shown in Figure 5.8. Fourteen of these are supplied by the soil. The
others (carbon, hydrogen and oxygen) come from air or water.
Essential nutrient elements
Macro-nutrients (major)
Micro-nutrients (minor / trace)
• From the soil:
nitrogen
phosphorus primary elements
potassium
calcium
magnesium secondary elements
sulphur
• From air and water:
carbon, hydrogen, oxygen
• From the soil:
iron
copper
zinc
manganese
cobalt
molybdenum
chlorine
boron
required in
small amounts
Figure 5.8 The essential nutrient elements.
macro-nutrients ▶
micro-nutrients ▶
74
Nine of the elements are required in large quantities and are called macronutrients. The others are required in only small amounts and are the micronutrients or trace elements. The macro-nutrient elements are present in soils
as ions and may be derived from the parent rock, released from organic matter
by the activities of soil micro-organisms or added in the form of fertilisers. For
example, calcium and magnesium occur in limestone and dolomite. Dolomite is
a rock that is processed into dolomitic limestone and used as a liming material on
acidic soils to reduce the acidity.
5: Environmental factors affecting crop growth
primary elements ▶
secondary elements ▶
In Figure 5.8, three of the major nutrients are called primary elements. These
are nitrogen, phosphorus and potassium and can be supplied to crops in the
form of inorganic fertilisers (see Section 5.8). Calcium, magnesium and sulphur
are known as secondary elements. Calcium and magnesium help to improve
soil aggregation. This affects aeration and tilth in clay soils. Sulphur, needed
by all plants for protein synthesis, is obtained from rainwater, farm manure or
superphosphate fertiliser added to the soil.
Table 5.5 summarises the roles of the primary and secondary macro-nutrients in
crop production.
Nutrient
Nitrogen
Phosphorus
Potassium
Calcium
Magnesium
Sulphur
Role in crop production
• Needed for protein synthesis.
• Promotes general growth and
juiciness of fruits and grains.
• Speeds up cell division.
• Promotes growth and development
of root systems.
• Essential for chlorophyll
development; necessary for
photosynthesis.
• Promotes root systems.
• Influences fruit-setting.
• Essential for growth and
development of root tips.
• Essential for cell-wall development.
• Essential for chlorophyll formation.
• Involved in many enzyme reactions.
• Needed for making proteins.
Signs of deficiency
• Stunted plant growth; poor root and
shoot development.
• Yellowish leaves.
• Stunted growth, particularly of root
systems.
• Leaves become mottled with
scorching at the edges.
• Stunted growth.
• Yellowish colour in leaves.
• Chlorosis (yellowing of the leaves).
• Thin or slender plants.
• Pale green or yellow leaves.
• Fruits ripen late.
Table 5.5 The roles of the primary and secondary major nutrients.
The micro-nutrients are required by plants in only very small quantities. If there
is a deficiency, indicated by poor growth of a crop, they can be supplied to the
plants as foliar sprays (applied to the leaves) or combined with other fertilisers
and added to the soil.
Soil particle–soil nutrient relationship
cations ▶
anions ▶
Plants obtain soil nutrients from two main sources: the adsorbed nutrients on the
surfaces of clay and humus particles (colloids) and the dissolved minerals in the
soil solution. These essential nutrient elements are present in the form of ions.
Ions that are positively charged are called cations, for example, K+, Ca++ and
Mg++. Ions that are negatively charged are called anions, for example, Cl–, SO4–
and NO3–. The uptake of ions by the roots is not passive but requires energy from
aerobic respiration.
Soil particles, both mineral and organic, are reservoirs of soil nutrient elements.
These elements may be held in combinations not readily available for plant
nutrition and are released by physical, chemical and biological processes. The rate
of release is affected by environmental conditions in the soil. Table 5.6 summarises
some soil minerals and their associated nutrient elements.
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Section B: Crop production
Group of soil
particles
Organic
Inorganic
Soil particles
Soil minerals
Soil nutrient elements
Humus
Sand
—
Quartz, feldspars, micas, hornblende
Inorganic
Silt
Feldspars, micas, haematite, limonite
Inorganic
Clay
Kaolinite, illite, montmorillonite, vermiculite, chlorite
Nitrogen, sulphur, phosphorus, copper
Potassium, calcium, iron, magnesium,
sodium
Calcium, iron, sodium, potassium,
magnesium
Magnesium, iron, manganese, zinc
Table 5.6 Soil minerals and their associated soil nutrient elements.
leaching ▶
ITQ 6
Why are clay and humus particles
important in soils?
micelle ▶
Leaching
Once nutrients have been released into the soil, they may be lost through
leaching. In this process, soluble substances are removed by water. The nature
and size of the soil particles has an effect on this loss of nutrients. For example,
leaching is greater in soils made up of coarse sand particles than in soils with
finer particles, such as silt and clay. Potassium, a nutrient found in most soils, is
generally low in sandy soils because of leaching.
Similarly, chemical reactions and the exchange of soil nutrient elements are
associated with the nature and size of clay and humus particles. Clay and humus
particles are very small but they possess large surface areas and negative charges
that attract positive nutrient ions and water.
Each particle is referred to as a micelle or micro-cell and has a great capacity for
attracting positively charged nutrient ions. This attraction of nutrient ions to the
surfaces of the clay and humus particles enables nutrients to be held in the soil so
that they are not removed by leaching.
Soil pH
pH of the soil ▶
The pH of the soil is a measure of the hydrogen ion concentration of the soil
water. The pH is measured on a scale from 1 to 14. A value of 7 is neutral; values
below 7 are acidic and those from 8 to 14 are alkaline. The pH range for soils
is from 3 to 10, but most tropical soils have a pH value between 5 and 7. Plant
nutrients are generally most available to plants in the pH range 5.5 to 6.5.
Soils in limestone areas are slightly alkaline because of particles of calcium
carbonate. Sandy soils tend to be slightly acidic because the rain causes leaching
of soluble ions that would otherwise neutralise the acidity.
Acid soils are less fertile than alkaline soils because the acidity causes the mineral
salts to be more soluble and therefore more easily washed away by rain. When
rainfall is greater than evaporation, calcium, magnesium and potassium ions
are leached away from the topsoil as the water moves downwards. The soil
becomes more acidic because hydrogen ions replace the calcium, magnesium and
potassium ions. In tropical regions, minerals that are less soluble in water, such as
aluminium, kaolinite and quartz, are left in the top layers of soil. Soil acidity can
be reduced by liming.
universal indicator ▶
76
The pH can be determined using universal indicator test strips. Farmers are
interested in the pH of the soil as certain crops prefer a certain pH. If necessary,
the farmers can adjust the pH to suit their crops. Limestone (calcium carbonate)
can be added to increase the alkalinity of the soil, and organic mulches, peat or
sulphur can be added to increase the acidity of the soil.
5: Environmental factors affecting crop growth
5.6 The availability of soil water for crop use
Soil water, from rainfall or irrigation, is needed for plant growth and for the soil
organisms. It may be present as a soil solution in the pore spaces or held as a film
around tiny mineral particles (adsorbed water). Figure 5.9 shows this. Dissolved
mineral salts in the soil solution supply essential nutrients to plants.
hygroscopic water ▶
Hygroscopic water is absorbed into the soil from the atmosphere. The water is
held so tightly around the soil particles that the plants are unable to get enough
of the water to survive.
gravitational water ▶
Gravitational water is temporary soil water that results from prolonged
infiltration from heavy rainfall or flooding. The water moves downwards to the
groundwater under the influence of gravity.
field capacity ▶
capillary water ▶
After rainfall, the soil may be saturated with water. But following drainage, the
level will reach field capacity, which is the optimum water level for plant growth.
At field capacity, the larger pore spaces are filled with a continuous stream of
water that moves upwards by capillarity (capillary water). This can be used by
plants for photosynthesis. Excess water is lost from plants by transpiration.
hygroscopic water
remaining water
adheres to soil
particles
capillary water
gravitational water
water held in micropores
(available water; plant
roots can absorb this)
drains right through
wilting point
field capacity
Figure 5.9 Soil water.
temporary wilting ▶
ITQ 7
Explain the difference between
hygroscopic water, capillary water
and gravitational water.
permanent wilting ▶
If soil water is lost and not replenished, crop plants begin to wilt during the
day but regain their turgidity at night. This is known as temporary wilting. It
indicates that the soil water level has decreased and that the plant roots cannot
take up enough water to replace that being lost by transpiration during the day.
Turgidity is regained at night because the temperature drops and less water is lost
from plants by transpiration.
If soil water loss persists without replacement, the roots are unable to obtain
any water, so leaves and soft stems droop and do not recover at night. This state
is referred to as permanent wilting and can result in the death of the crop.
Permanent wilting is an indication that the capillary stream of water in the pore
spaces is broken. Plant roots are unable to take up the adsorbed water, which is
held tightly around soil particles.
77
Section B: Crop production
Soil air
soil aeration ▶
Soil air and soil water share the pore space together, and interchangeably, in
the soil. The volume percentage of air present in the pore space is referred to as
the soil aeration. Following heavy rainfall, as water drains through the soil, air
moves into the larger pore spaces that were formerly occupied by water. As the
soil water continues to drain away or is used, soil air enters the smaller pores.
The composition of the soil air varies, depending on soil-water relationships and
the biological activities in the soil.
Generally, in soil air:
• the moisture content is higher than in atmospheric air
• the oxygen level is lower
• the carbon dioxide level is higher.
ITQ 8
Explain the relationship between
soil air and soil water.
The differences in levels of oxygen and carbon dioxide are due to the respiration
of plant roots and soil organisms.
In practical farming, soil aeration occurs when the farmer carries out tillage and
drainage. Soil aeration encourages the growth of plant roots. It also ensures
there is enough oxygen for the respiration of micro-organisms that bring about
decomposition. In addition, aeration helps to remove toxic gases.
5.7 The importance of major and minor
nutrients used in crop production
carbon and nitrogen cycles ▶
producers ▶
consumers ▶
decomposers ▶
The carbon and nitrogen cycles are important in making carbon and nitrogen
compounds available for the activities of living organisms. Green plants are the
producers. They build up their food supplies from carbon dioxide, water and
sunlight (photosynthesis), and also use mineral ions from the soil.
The consumers are the animals that eat both plants and other animals.
The decomposers in the soil, such as bacteria and fungi, break down the dead
remains of other organisms, releasing nutrients for plants to use again.
Soil contains large numbers of micro-organisms, many involved in recycling
nutrients. Some of these organisms are described in Table 5.7. Bacteria and fungi
are of vital importance in nutrient recycling.
Name of group
Algae
Actinomycetes
Bacteria
Description
Simple photosynthetic organisms.
Minute thread-like organisms.
Single-celled organisms: spherical, spiral or rodshaped.
Fungi
Some microscopic, some filamentous forming
visible structures, e.g. mushrooms.
Microscopic, single-celled organisms; a few
present in most soils.
Microscopic; live in plant and animal cells.
Protozoa
Viruses
Table 5.7 Soil micro-organisms.
78
Role
Blue-green algae can fix atmospheric nitrogen in soil.
Help break down soil organic matter.
Involved in the nitrogen cycle in nitrogen-fixing, nitrification and
denitrification. Some are involved in other mineral cycles. They help
break down organic matter.
Important in humus formation; effective in decomposing plant
materials, e.g. lignin and cellulose.
Feed on soil bacteria.
Cause diseases in crops and livestock.
5: Environmental factors affecting crop growth
The carbon cycle
carbon cycle ▶
The carbon cycle (Figure 5.10) shows how carbon and carbon compounds are
linked to natural processes and products. Three processes form the basis of the
carbon cycle: photosynthesis, respiration and decomposition.
carbon dioxide
in the air
photosynthesis
plants eaten
by animals
green plants
make sugars
from carbon
dioxide
respiration
death and
decay
urine and
faeces
decomposition
(bacteria, fungi)
Figure 5.10 The carbon cycle.
photosynthesis ▶
respiration ▶
decomposition ▶
During photosynthesis, plants take in carbon dioxide from the atmosphere and
use it to manufacture simple sugars (which are carbon-containing compounds).
These are then built up within the plant to make carbohydrates, lipids and
proteins. Humans and animals are consumers. They eat the plants or plant
products thereby taking carbon compounds into their bodies.
All living organisms require energy, which is released from carbon compounds
through respiration. Carbon in the form of carbon dioxide is a waste product of
respiration and is released into the atmosphere.
In the process of decomposition, waste products from crop residues, green
manures, animal urine and faeces, and dead and decaying organisms are digested
by micro-organisms. These micro-organisms gain energy from the decomposition
process and release carbon dioxide into the atmosphere as a result of their
respiration.
Some carbon dioxide dissolves in soil water, forming carbonic acid, carbonates
and bicarbonates of calcium, magnesium and potassium. As these compounds are
soluble, they can be used by plants. Often they are lost through leaching.
When carbon-containing fuels (wood, coal, petroleum and natural gas) are
burned, carbon dioxide is released into the atmosphere. Coal and petroleum come
from plants that were buried millions of years ago, so these fuels are referred to
as fossil fuels.
The carbon cycle summarises the circulation of carbon compounds in natural
processes. It also enables us to understand some of the causes of the greenhouse
effect, which keeps the Earth warm. Global warming results from increasing
levels of carbon dioxide in the atmosphere.
79
Section B: Crop production
The nitrogen cycle
Nitrogen is essential for forming plant and animal proteins. Figure 5.11 shows the
nitrogen cycle. Nitrogen as a gas makes up 79% of the Earth’s atmosphere, but
few organisms can use it in this form.
How nitrogen in the air is made available to plants
During thunderstorms, lightning converts gaseous nitrogen into nitrogen oxides,
which dissolve in rainwater and get washed into the soil as nitrates. Plants can use
nitrates and they absorb them through their roots.
plant and
animal protein
nitrogen
in the air
lightning
(lightning fixation)
denitrification
(denitrifying bacteria)
plants eaten
by animals
nitrogen-fixing
bacteria
Clostridium and
Azotobacter
nitrates
in the soil
urine
and faeces
Rhizobium
nitrates are taken
up by plant roots
nitrification by
Nitrobacter bacteria
nitrites
in the soil
death and
decay
nitrification by
Nitrosomonas
bacteria
bacteria and fungi
(decomposing organisms)
ammonium
compounds
in the soil
Figure 5.11 The nitrogen cycle.
nitrogen-fixing bacteria ▶
Atmospheric nitrogen is ‘fixed’ into nitrates by two different groups of nitrogenfixing bacteria found in the soil. Rhizobium bacteria enter the roots of leguminous
plants, such as peas and beans, and cause nodules to form (see Figure 5.12). The
bacteria live in the root nodules and take up nitrogen gas and convert it to
compounds of nitrogen, which the plants can use to make proteins.
Other bacteria, such as Azotobacter and Clostridium, live freely in the soil. These
bacteria convert nitrogen into ammonium compounds, which can be used by
some plants or oxidised to nitrites and nitrates by other bacteria in the soil.
Figure 5.12 Root nodules containing
nitrogen-fixing bacteria.
80
Nitrifying bacteria
The organic matter that comes from the remains of plants, animals, urine, faeces,
crop residues and compost undergoes decomposition by bacteria and fungi in the
soil and ammonium compounds are formed.
5: Environmental factors affecting crop growth
nitrifying bacteria ▶
denitrifying bacteria ▶
ITQ 9
Explain the difference between
nitrifying and denitrifying bacteria.
Under aerobic conditions, ammonium compounds are converted to nitrites and
nitrates by nitrifying bacteria. Nitrosomonas converts ammonium compounds to
nitrites and Nitrobacter converts nitrites to nitrates. The nitrates are then taken up
by the plant roots and built into plant protein.
Denitrifying bacteria
In anaerobic soil conditions, denitrifying bacteria obtain their energy by
converting nitrates to nitrogen gas, which escapes from the soil into the
atmosphere. This is also a part of the nitrogen cycle.
Importance of minor nutrients in crop production
The minor nutrients are referred to as micro-nutrients or trace elements. They
are important for plant growth as they are found in many of the enzymes needed
for cells to function properly (see Table 5.8). It is not always easy to identify the
effects of individual elements. For example, yellowing of leaves could be due to a
lack of magnesium, sulphur, nitrogen or iron.
Element
Manganese
Iron
Copper
Zinc
Molybdenum
Boron
Function
Present in enzymes involved in
respiration.
Present in enzymes; essential for the
formation of chlorophyll.
Present in enzymes involved in
respiration.
Present in respiratory enzymes.
Involved in amino acid synthesis in
plants; nitrogen fixation.
Needed for normal cell division in
root and shoot tips.
Signs of deficiency
Flecks appear on leaves.
Yellowing of young leaves caused by
lack of chlorophyll.
Die-back of shoots.
‘Mottle leaf’ of citrus; ‘sickle-leaf’
of cocoa.
Reduced growth; ‘scald’ disease
of beans.
Abnormal growth and death of shoot
tips; ‘heart-rot’ of beet; ‘stem-crack’
of celery.
Table 5.8 Some minor (trace) elements, their functions and signs of deficiency.
5.8 The factors affecting soil fertility
Soil fertility
soil fertility ▶
Soil fertility refers to the productive capacity of a soil in which the soil conditions,
nutrient supply and availability are favourable for the growth of crop plants.
A fertile soil has the following characteristics.
• It is moderately porous with good aeration and drainage.
• It retains adequate moisture.
• It contains a lot of organic matter and is rich in nutrient elements.
• It has adequate permeability for roots.
• It is slightly acidic (optimum pH 5.5 to 6.5).
• It is relatively free from toxins, pests and diseases.
Soil fertility is affected by climate, topography, soil factors such as the physical and
chemical conditions of the soil and the nature of the parent material, as well as
fertilisers and soil management.
81
Section B: Crop production
Topography
ITQ 10
How do topographic features affect
soil fertility in the Caribbean?
Most Caribbean countries are hilly, which affects soil fertility. Soils on mountain
slopes are shallow and the most fertile soils are in the valleys. As accessibility
is difficult in hilly areas, farmers find it difficult to till the soil and improve soil
fertility. Farmers are restricted in their ability to use heavy farm machinery in the
hills, preventing effective land preparation from being done. Therefore, farming
in the hilly areas is usually limited to small enterprises.
The nature of the parent material
parent materials ▶
igneous ▶
The parent materials of soils are the rocks that make up the Earth’s crust.
These rocks vary in size, from large masses to small fragments such as boulders,
gravel and stones. All rocks are made up of inorganic minerals that have become
consolidated and hardened geologically. They are weathered by physical, chemical
and biological forces to form soils.
Types of rocks
Igneous rocks are cooled and solidified molten rock. The major minerals in these
rocks are quartz, micas and feldspars.
Types of rocks
Igneous
Sedimentary
Metamorphic
Examples:
• quartz
• micas
• feldspars
Examples:
• sandstone
• shale
• limestone
Examples:
• quartzite
• slate
• schist
Figure 5.13 Types of rocks.
sedimentary ▶
Sedimentary rocks are formed from other rocks that have been weathered, and
the particles transported and deposited. Over time, the overlying sediments add
pressure, which gradually hardens lower sediments into sedimentary rocks such
as sandstone, shale and limestone.
metamorphic ▶
Metamorphic rocks result from changes that occur to igneous and sedimentary
rocks when they are subjected to intense heat, pressure and chemical processes
within the Earth’s crust. In the case of sedimentary rocks, sandstone is changed
to quartzite, shale to slate and limestone to marble. Igneous rocks are changed to
gneisses and schists.
Practical activity:
Test a range of soil types for
acidity and alkalinity using
weak hydrochloric acid (1.0 M).
Record your results in a table.
The fertility of soils depends on the nature and sizes of the particles derived from
the rocks. Soils derived from limestone tend to be alkaline and those derived from
sandstone are usually acidic.
Land management
The way in which land is managed by farmers has an impact on soil fertility. Good
management benefits the soil and can bring about higher yields of crops.
82
5: Environmental factors affecting crop growth
ITQ 11
Describe how good land
management practices can improve
soil fertility.
agro-forestry ▶
silviculture ▶
Good management practices include:
• agro-forestry, which conserves topsoil and water and also preserves the soil
organisms
• applying fertilisers, organic matter and lime to improve the nutrient status of
the soil, maintain fertility and promote crop growth
• avoiding the burning of vegetation
• pruning, tilling, draining, mulching, staking, cover cropping and planting
shade trees on pastures – all these improve the condition of the soil.
Agro-forestry is a system of land use in which harvestable trees or shrubs are
grown among or around crops or on pastureland. Silviculture is the growing of
forest trees.
Taking care with chemicals
The use of hazardous chemicals and the inefficient disposal of waste materials will
pollute the water and soil. There is also a risk that these chemicals will destroy the
soil micro-organisms.
Inorganic and organic fertilisers
inorganic fertilisers ▶
Inorganic fertilisers include sulphate of ammonia, nitrate of potash (saltpetre)
and NPK (consisting of nitrogen, phosphorus and potassium). These fertilisers
are manufactured through chemical processes. They are also known as artificial
fertilisers.
organic fertilisers ▶
Organic fertilisers are derived from plant and animal remains. Organic fertilisers
are referred to as manures or compost. They improve the structure, aeration and
drainage of soils in addition to supplying nutrients.
Both manures and inorganic fertilisers supply nutrients. The manures maintain
and improve the soil’s structural properties and supply essential nutrients. The
artificial fertilisers contribute a concentrated supply of essential soil nutrients but
do not affect the structural properties of the soil.
soil amendments ▶
Soil amendments include substances such as lime, gypsum, sulphur, bagasse,
coffee hulls, manure and organic fertilisers, which may be used to improve soil
properties. These substances make the soil more productive, correct soil nutrient
deficiencies and replace nutrient elements lost through crop removal. The
maintenance of soil fertility is described in Section 5.9.
Practical activity:
Working in groups, look at different types of soil amendments. Complete a table like the one here. One example has been done for you.
Amendment
Example: Nutmeg hull
Description
Hard seed hull
How will it improve the soil properties?
Increases porosity and soil texture; takes time for hull to break down
so slow release of nutrients into soil.
83
Section B: Crop production
Fertiliser ratio
simple fertilisers ▶
compound fertilisers ▶
fertiliser ratio ▶
ITQ 12
State the importance of the
manufacturers’ labels on bags of
fertiliser.
Inorganic fertilisers can be simple fertilisers, supplying one of the major nutrient
elements: nitrogen, phosphorus or potassium. For example, urea provides
nitrogen, single superphosphate provides phosphorus and potassium chloride
provides potassium.
What does fertiliser ratio mean?
Mixed or compound fertilisers provide two or more nutrient elements in a
simple fertiliser ratio. Low-grade fertilisers contain less than 25% of the nutrient
elements, medium-grade fertilisers contain between 25% and 40% and highgrade fertilisers contain more than 40%.
Manufacturers of fertilisers normally use labels that indicate the percentage
of nitrogen (N), phosphorus (P) and potassium (K), together with the ratio of
these three elements, on their fertiliser bags. Labelling indicates the type and
grade of fertiliser that is offered for sale, as well as the nutrient content and the
nutrient ratio.
5.9 Maintaining soil fertility
Keeping the soil in a fertile state is a challenge for farmers. These methods can be
used:
• soil amendments
• cropping systems
• soil and land management
• irrigation and drainage.
Methods or techniques of improving
and maintaining soil fertility
Soil amendments
Cropping systems
Cultural practices
Soil erosion
• manures
• fertilisers
• compost
• organic matter
• liming materials
• crop rotation
• cover crops
• inter-cropping
• multiple cropping
• moulding
• tillage
• drainage
• irrigation
• mulching
• vegetative cover
• strip cropping
• contouring
• grass barriers
• terracing
Figure 5.14 Methods of improving and maintaining soil fertility.
Soil amendments
Soil amendments include any materials that supply ingredients and nutrient
elements, which collectively improve soil structure and maintain soil fertility.
They vary in type, but their main functions are to improve soil structure, to
increase water-holding capacity and permeability, to supply nutrient elements, to
ensure adequate drainage and aeration, and to neutralise soil acidity.
Soil amendments include:
• manures
• inorganic fertilisers
• organic matter
• liming materials.
84
5: Environmental factors affecting crop growth
manures ▶
Manures
Manures are also known as organic fertilisers. There are five groups:
• Pen manures are the partially decomposed solid materials derived from
livestock pens. They consist of dung / droppings, bedding or litter, and slurry
from washing the pens of dairy cattle and other farm animals.
• Compost manure is derived from leaf litter and crop residues.
• Green manure refers to a green crop, preferably a legume, which is ploughed
into the soil at its flowering stage. This manure adds nitrogen to the soil.
• Guano is made from bird droppings and contains large amounts of nitrogen
and potash.
• Bonemeal is made by grinding bones from meat-processing companies. It
contains some nitrogen but has large amounts of phosphate.
Manures, such as pen, guano and compost, are spread evenly over ploughed land
and rotovated into the soil. If the manure is liquid, as in the case of slurry, it is
spread mechanically over ploughed land and pasture using a slurry spreader.
inorganic fertilisers ▶
NPK fertilisers ▶
Inorganic fertilisers
Inorganic fertilisers may be simple inorganic fertilisers, supplying one of
the major nutrients, or compound inorganic fertilisers, supplying two or more
nutrients. Some examples of simple fertilisers and the nutrients they supply are urea
(nitrogen), potassium chloride (potassium), triple superphosphate (phosphorus)
and ammonium sulphate (nitrogen; also lowers the soil pH). Compound fertilisers
usually contain the three major nutrients nitrogen, phosphorus and potassium,
and are referred to as NPK fertilisers. The ratios and percentages of these three
nutrients vary in different grades of NPK fertilisers (see Section 5.8).
There are several ways to apply fertilisers. The method used will depend on the
type of fertiliser, the area to be covered and the crop to which it is being applied.
For large-scale applications, the fertiliser is usually spread by machinery, but on
small farms it is done by hand.
Farmers need to determine the fertiliser requirements of their crops. To do this,
they need to consider several factors (see Table 5.9).
Factor
Type of soil
Crop group
Consideration
• Determine whether soil is sandy, clay or loam;
nutrients leach easily from sandy soils.
• Need to check pH of soil as well.
• Consider whether crop is a leafy vegetable, cereal,
legume, root crop, cucurbit or fruit.
Crop stage
• Crop has different nutrient requirements at different
stages of growth.
Weather conditions
• Consider whether it is wet or dry at the time of
application.
Fertiliser requirement
• May need to consider a mixture of organic manures
and inorganic fertilisers, depending on soil type.
• Leafy vegetables and cereals need nitrogen and
phosphorus.
• Root crops need phosphate and potassium.
• Cucurbit and fruit crops need nitrogen and potassium.
• Legumes are nitrogen-fixing so they reduce the need
for nitrogen.
• In their vegetative state, crops need large amounts of
nitrogen.
• During the flowering and fruiting stages, they need
large amounts of phosphorus and potassium.
• If the soil is too wet, nutrients may leach out quickly.
• If it is too dry, nutrients may not be taken up by the
crop.
Table 5.9 Factors to consider when determining the fertiliser requirements of crops.
85
Section B: Crop production
Methods of application depend on the:
• type, age and stage of development of the crop
• system of planting – distance apart of rows; distance apart of plants
• machinery and equipment available
• availability of labour
• weather conditions.
Practical activity:
Use the internet to watch
demonstrations of the different
methods of applying fertilisers.
Figure 5.15 shows the different methods of application.
soil surface
tree crop
7–9 cm
fertiliser
seed
(drilled)
row crop
1. broadcasting
2. direct placement
upper
slope
fertiliser on soil surface
or beneath soil
6. hillside application
holes made with crowbar
7. hole placement
fertiliser
3. row application
fertiliser
in holes
fertiliser
(drilled)
4. band application
5. drill application
liquid fertiliser
fertiliser
crop
plants
rotovator
8. soil incorporation
9. foliar application
Figure 5.15 Methods of applying fertilisers.
organic matter ▶
liming materials ▶
Organic matter
Organic matter, other than manures and compost, may be used on soils
to improve the water-holding capacity. Waste materials, such as bagasse from
sugar cane processing, coffee hulls and sawdust, may be used for this purpose.
Sometimes they are used as ‘fillers’ in fertilisers, where they add bulk and serve
as inert substances.
Liming materials
Liming materials are usually applied to acidic soils to reduce soil acidity,
increase calcium and magnesium ions in the soil, reduce the concentrations of
iron, aluminium and manganese, and promote the activities of the soil microorganisms.
Lime may be added to the soil as:
• calcium oxide [CaO], referred to as quicklime or burnt lime
• calcium hydroxide [Ca(OH)2], known as slaked lime
• calcium carbonate [(CaCO3)], also known as chalk or ground limestone
• calcium magnesium carbonate [CaMg(CO3)], also known as dolomitic
limestone.
Lime is usually applied to acidic soil during the preparation of the land and before
any crops have been planted. Before it is done, the soil is tested in a laboratory to
determine the recommended rate of application. In the Caribbean, soil testing is
carried out by the Ministry of Agriculture at no cost to farmers.
86
5: Environmental factors affecting crop growth
The land to be limed is ploughed using a disc plough or a mouldboard plough.
Lime is then spread evenly over the ploughed area, at the recommended rate,
either manually or mechanically. Using a rotovator, the lime is mixed thoroughly
within the top half of the furrow slice (7 – 10 cm).
Finely ground limestone applied during land preparation produces speedier and
more effective results. Dolomitic limestone is often preferred because it supplies
both calcium and magnesium to the soil.
Cropping systems
Cropping systems include crop rotation, cover crops, intercropping and multiple
cropping (see Unit 8). The inclusion of deep-rooted, shallow-rooted, leguminous
and cover crops in a cropping system improves soil fertility by cycling nutrients
between the upper and lower levels of the soil. Leguminous crops encourage
nitrogen fixation. Adequate vegetative cover reduces the loss of soil and nutrients.
Cultural practices
The physical condition of the soil can be improved and soil fertility maintained by
tillage, drainage and irrigation where needed. Tillage maintains soil structure and
contributes to the aeration and drainage. It also makes it easier for roots to grow
and incorporates organic material into the soil. Adequate drainage is important
in the wet season. In the dry season, the soil must retain enough water for crop
growth and this may mean that some form of irrigation is necessary (see Unit 22).
Soil erosion
soil erosion ▶
Practical activity:
Carry out a demonstration of soil
erosion using models that you
have made.
Soil erosion is the process by which particles of soil are carried away from one
area, by water or wind, and deposited at another area. Soil erosion can also be
caused by the actions of people and animals. All soils undergo erosion, but if there
has been no clearing or cultivation of the land, the rate of erosion is slow and
allows the processes of soil formation to continue. If vegetative cover is removed,
for example, when the land is cleared for agriculture, forestry or grazing, then the
soil is exposed to wind and water. Soil erosion is speeded up and can become a
problem.
Factors that control the amount of soil erosion are:
• the amount of rainfall
• the wind speed and intensity
• the type of rock
• the slope of the land
• the amount and type of vegetative cover
• the presence of grazing animals.
Different types of soil erosion
Soil erosion can be entirely due to natural causes or it can result from human
activities.
natural soil erosion ▶
Natural soil erosion occurs in an undisturbed natural environment as a result of:
• running water on steep slopes
• running water on sloping areas with loose, friable soil
• landslides of loose, saturated soil, overlaying an impervious layer, in hilly or
mountainous areas
• strong winds blowing over loose soil in dry, semi-arid or arid (desert) areas
• sea waves pounding the land in coastal areas.
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Section B: Crop production
accelerated soil erosion ▶
Accelerated soil erosion occurs as a result of the activities of people who disturb
the natural environment, creating soil conditions that speed up soil erosion by
water and wind.
These activities include:
• burning the vegetation on the land, including ‘slash and burn’ agriculture
• overgrazing of pastures by livestock
• deforestation (the cutting down and removal of trees)
• mining and quarrying operations
• creating bare soil patches on the land by overweeding or brushcutting
too closely
• not using a ground cover, such as a cover crop or a mulch
• unsuitable cultural or soil conservation practices on hilly terrain.
splash erosion
The causes of soil erosion
water flows downhill
Water
In the Caribbean, soil erosion by water is a problem during the rainy season.
soil builds up
Type of erosion Cause
Splash
Impact of heavy raindrops.
sheet erosion
Sheet
Rill
Gully
Landslide
rill erosion on a hillside
Loss of topsoil
gully erosion (rills have joined together)
Figure 5.16 Some examples of soil erosion
caused by water.
soil creep ▶
saltation ▶
Running water dislodges soil
particles.
Water running down a bare area of
sloping land.
High-intensity rainfall and fastflowing water on a sloping area
of land.
Intensive rainfall on loose soil
above a sloping impervious layer.
Running water in hilly or
mountainous areas.
Silting up of
water courses
Soil particles carried away by
running water.
Alluvial soil
deposits
Soil particles brought down
mountainous slopes by streams
and rivers.
Effects
Dislodges soil particles, which splash on
to young plants. Soil particles are carried
away by running water.
Soil particles move downhill as a sheet of
soil. Soil gathers at the base of the hill.
Creates many tiny channels, known as rills,
where soil has eroded away.
Rills become more eroded. This leads to
fewer, wider and deeper channels, which
are called gullies.
Loose soil slides away in this situation
when it is saturated with water.
If soil is not protected by a cover crop,
organic matter or a mulch, topsoil can be
lost.
Causes silting up of streams and rivers,
eventually leading to flooding of a river
basin.
Alluvial soil deposits form at the mouths of
rivers, on riverbanks and on flood plains.
Table 5.10 The types, causes and effects of soil erosion by water.
Wind
Wind can also cause soil erosion. Strong winds can cause soil creep, which is the
gradual movement of loose soil particles, such as sand, on the soil surface towards
the opposite direction from which the wind is blowing.
Saltation of soil particles occurs when strong winds cause loose soil particles to
leap suddenly, become airborne for a while and then eventually fall to the ground,
forming heaped areas of soil. Where mining, quarrying and land preparation
operations are carried out under dry soil conditions, soil particles in suspension
are transported by winds and may be deposited many kilometres away.
Soil particles in the atmosphere can cause respiratory problems in people and in
farm animals.
88
5: Environmental factors affecting crop growth
burning vegetation ▶
Burning
Burning vegetation as part of land clearing has positive and negative effects.
Among the positive effects are:
• unwanted material, such as cane trash, is burned out, so cane-cutters work
more efficiently
• land clearing can be carried out more speedily
• harmful plants, such as nettles, are destroyed
• harmful animals, such as snakes, scorpions, centipedes and nests of wasps, are
destroyed
• the ashes on the land add potash to the soil
• the soil is sterilised as a result of the intense heat.
However, burning vegetation is not recommended as it creates smoke pollution in
the atmosphere. It is recommended instead that harmful plants and crop residues
are cut and stacked in an area where they can decompose slowly.
ITQ 13
List TWO advantages and TWO
disadvantages of burning vegetation
when clearing land for crop
production.
Other negative effects of burning vegetation are:
• the destruction of organic matter that took many years to accumulate
• humus in the soil is also destroyed
• soil organisms are killed
• the soil surface becomes bare, with no plant cover so it is more exposed to soil
erosion
• soil water is lost more rapidly through evaporation
• leaching of nutrients can occur more easily.
Animals
Any bare land exposed to heavy rainfall can lose nutrients through leaching and
mineral particles from runoff. The effects of animals, through grazing or trampling,
can leave soil bare and open to erosion, particularly in the rainy season.
5.10 Soil and water conservation methods
soil conservation ▶
Soil conservation refers to protecting the soil from erosion and maintaining its
fertility. It is of great importance to agriculture in the Caribbean region. Cultural
practices, such as minimum tillage, ridging and applying mulch, play a vital role
in preventing soil erosion and maintaining soil fertility.
minimum tillage ▶
Minimum tillage is where soil is only cultivated to provide the planting holes
and rows for the crops. It does not expose soil to rainwater and can therefore
reduce erosion in hilly and mountainous areas.
ridging ▶
Ridging is where ridges are built across a slope to prevent the rapid flow of water
downhill. This can reduce soil erosion and help to retain water in the soil.
mulches ▶
Organic matter, such as mulches or weeds that have been uprooted and left lying
on the soil, will reduce the direct impact of raindrops and allow water to filter
slowly down into the soil. A mulch is a protective covering over the soil surface,
usually of organic matter.
Rotational grazing helps to conserve pasture, because the animals are moved
around and the formation of bare patches is avoided (see Section 12.5).
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Section B: Crop production
vegetative cover ▶
Figure 5.17 A cover crop of pigeon pea:
creating vegetative cover and fixing nitrogen
into the soil.
leaf litter ▶
The importance of vegetative cover
Vegetative cover (see Figure 5.17) refers to a layer of vegetation covering the
surface of the soil. Vegetation is used to prevent soil erosion and includes the
following practices.
• Cover crops, which grow and spread rapidly, are planted to provide a
protective covering on the ground. Legumes are often used as a cover crop.
• Contour cropping is carried out. In this system, crops are cultivated along the
contours of sloping land.
• Strip cropping is used. This is very similar to contour cropping. In this system,
deep-rooted and shallow-rooted crops are cultivated in strips, 1 – 1.5 m wide,
across a hill slope.
• Grass barriers (normally included in a strip cropping system) are used. The
grass is planted in line with the contours of the land. The fibrous roots of the
grass grow in thick clusters and bind the soil particles together.
• Grassed drains, using matted grass such as Savanna or Bermuda, which is
grown, cut and kept low in box drains, are dug across or down gentle slopes.
Forests and soil conservation
Forests are vital in soil management and water management. The roots of trees
and forest plants grow in thick clusters, binding soil particles and controlling soil
erosion. The leaf litter that builds up provides a thick layer of organic matter
on the soil surface, covering and protecting the soil and reducing evaporation.
This organic matter is then decomposed by soil micro-organisms and nutrients
are released into the soil. The activities of other soil organisms mix the upper and
lower layers of the soil so the nutrients are cycled. The forest canopy provides
shade and helps to control the drying out of streams.
The planting of forest trees in mountainous regions can control soil erosion.
Forests may be established as windbreaks in areas where the soil is loose and
liable to wind erosion. Sometimes forest trees are cultivated amongst food crops
such as banana, cassava, citrus and avocado. This is an example of agro-forestry.
The trees stabilise the soil and provide vegetative cover and shade.
windbreaks ▶
terracing ▶
contour ploughing ▶
In arid and semi-arid areas, wind erosion is a major problem and the most
common method used to conserve the soil is the construction of windbreaks.
Rows of trees are planted along the edges of cultivated areas. The trees slow down
the speed of the wind and prevent large amounts of sand or soil being blown
away to other areas.
Terracing and contour ploughing
Terracing involves the construction of relatively flat strips of land along the
contours of a hillside. This process creates a number of steps, which are sometimes
referred to as bench terraces. The broad banks of earth prevent water running
down the slope, thus controlling soil loss and soil moisture.
On gentle slopes, contour ploughing is practised. Land is cultivated along
the contours, preventing water flowing downhill. Before contour ploughing or
terracing, the farmer needs to establish the contour lines. This can be done using
a simple A-frame and marking the lines with stones or sticks.
Water conservation
The Caribbean climate has a rainy season and a dry season, so water conservation
is essential on most Caribbean farms. Farmers depend on water-storage systems,
drains and dry farming techniques.
90
5: Environmental factors affecting crop growth
water-storage systems ▶
Figure 5.18 Rainwater harvesting and
water storage in a mountain village.
gabions ▶
Water-storage systems used by farmers may include tanks, ponds, pools and
wells. Storage tanks can be made of galvanised iron, concrete reinforced with
steel or rotoplastic (PVC). Water-holding capacity varies and a farmer may have
three or more large tanks each holding 4 500 litres, depending on the nature and
size of the farm.
Ponds and pools are normally constructed in the dry season, so that they are
ready for the onset of the rainy season. Often, fish are reared in ponds providing
another source of income for the farmer. Wells can be dug out from 3 to 10 m
in depth. The water comes from underground springs and the height to which it
rises depends on the water table.
Gabions are cages of wire mesh, filled with soil, rocks or sand. They are used in
the construction of dams and retaining walls or to direct the flow of floodwater.
They have advantages over other methods of construction as they can be arranged
in various ways, are resistant to being washed away and drain freely. In a gabion
weir, the mesh baskets are arranged to form a channel down a slope to direct the
flow of water.
Practical activity:
In groups, make a poster about
local soil and water conservation
techniques. Use photographs and
diagrams to make your work more
interesting.
Figure 5.19 Gabions and concrete to retain the cliff above a freeway.
drainage ▶
Drainage channels are dug around fields and plots. These channels drain away
excess water in the rainy season and the water can be used for irrigation in the dry
season. Contour drains are constructed across the hill slope, along the contour, to
prevent the rapid flow of water downhill.
dry farming techniques ▶
Dry farming techniques include any technique that conserves water or prevents
the evaporation of too much water from the soil surface in the dry season. These
techniques include minimum tillage, mulching, using manure and compost
and growing cover crops. Controlled irrigation (using manual systems, hoses or
sprinklers) may be used to water crop plants in the dry season.
ITQ 14
Describe TWO ways that water can
be conserved on a farm.
91
Section B: Crop production
Revision map
Carbonic
acid
Water and
air
Water
Mineral
matter
Oxygen
Frost
Organic
matter
Soil
components
Chemical
weathering
Water
Physical
weathering
Land clearing,
mining and tillage
affect soil formation
and fertility
Soil formation
Organic matter in soil –
dead or decaying
remains of plants and
animals in the process
of being broken down
to form humus
Roots
Wind
Temperature
Biological
weathering
is where the actions
of living organisms
break up rocks
Soil components
Environmental
factors
affecting crop
growth
Mulching,
vegetation
cover and
irrigation can
help to keep
soils cool
Soil temperature
affects living organisms
in the soil, particularly
the activities of the
micro-organisms
Soil texture is
dependent on the size
and relative proportions
of the different
mineral particles
Soil properties
Soil porosity
and soil aeration are
interdependent and are
affected by the drainage
of the soil
Soil structure is
dependent on the
aggregation of the mineral
particles into lumps
and crumbs
Soil microbes
are essential
Biochemical
processes
The
decomposition of
organic matter
Aeration
92
Soil horizons have
different physical
and chemical
properties
Movement of
soil particles by water
and wind from one area
and deposited in
another area
Soil erosion
Accelerated soil
erosion caused
by humans
Natural soil
erosion occurs in a
natural undisturbed
environment
Soil
conservation
Soil air depends on
the air-water relationship
in the pore spaces
The formation
of humus
The recycling of
mineral elements
in the soil
Soil profile –
the vertical wall
of a pit showing
different horizontal
layers or soil
Root
respiration
Retain
vegetative
cover
Use contour
and strip cropping,
terracing and
windbreaks
Plant forests
5: Environmental factors affecting crop growth
Examination-style questions
Multiple-choice questions
Write down the number of the question followed by the letter
of the correct answer.
1.
2.
3.
4.
5.
6.
7.
8.
9.
Physical erosion of soil is caused by:
A carbonic acid
B oxygen
C wind
D humic acid.
In a soil profile, the zone of leaching is the:
A O horizon
B A horizon
C B horizon
D C horizon.
The percentage of organic matter in a loam soil is about:
A 50%
B 45%
C 25%
D 5%.
The finest mineral particles in soil are:
A silt
B clay
C sand
D gravel.
The composition of the soil air differs from that of the
atmosphere as it has:
A a higher oxygen content
B a lower moisture content
C a higher carbon dioxide content
D a higher nitrogen content.
Calcium is a macro-nutrient needed by plants for:
A protein synthesis
B chlorophyll formation
C development of root tips
D succulence of fruits.
Protozoa in the soil:
A fix atmospheric nitrogen
B feed on soil bacteria
C decompose lignin and cellulose
D cause diseases in crops.
Rhizobium is a bacterium involved in the process of:
A nitrification
B denitrification
C decomposition
D nitrogen fixation.
Boron is a trace element required by plants for:
A synthesis of respiratory enzymes
B formation of chlorophyll
C amino acid synthesis
D normal cell division.
10. Accelerated soil erosion is caused by:
A overgrazing
B landslides
C strong winds blowing over desert areas
D running water on steep slopes.
Short-answer and essay-type questions
11. (a) Explain the meaning of (i) soil aeration and (ii) soil porosity.
(b) State the importance of soil porosity in agriculture.
(c)
Why is it necessary for a farmer to aerate the soil of a
vegetable plot?
12. (a) Copy and label the typical soil-profile diagram below.
furrow slice
(topsoil)
subsoil
O1
O2
A1
A2
A3
O
organic matter, leaf mould,
forest litter
A
zone of leaching or
eluviation
B
zone of accumulation
or illuviation: a hardpan
may develop
C
parent material:
zone devoid of
biological activities
B1
B2
B3
parent
material
C
(b) State the importance of the layer O.
13. (a) (i) Name FOUR major factors that affect soil temperature.
(ii) Discuss TWO of the factors you have named in (i).
(b) List FOUR practices that are used by farmers to lower soil
temperature.
(c) State TWO beneficial effects of optimum soil temperature
in Caribbean agriculture.
14. Explain how soil nutrients are absorbed or taken up by the roots
of plants.
15. (a)Name ONE of each of the following bacteria associated
with the nitrogen cycle.
(i) Symbiotic nitrogen-fixing bacteria
(ii) Non-symbiotic nitrogen-fixing bacteria
(b) Explain the role of bacteria in the processes of nitrification
and denitrification related to the nitrogen cycle.
16. (a)State the following agricultural practices carried out
by farmers:
(i) TWO that help to improve the physical environment
(ii) TWO that are harmful to the physical environment.
(b) Discuss each of the agricultural practices you have stated
in (a), explaining their beneficial or harmful effects to
agriculture.
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Section B: Crop production
17. (a) List FIVE major factors that affect soil formation.
(b) Discuss any THREE of the factors that you have listed.
18. (a) State the effects of the following on soil formation:
(i) volcanic action
(ii) animal and plant matter.
(b)
Describe the activities of living organisms (biotic agents) in
soil formation.
19. (a) What is meant by the term ‘weathering of rocks’?
(b) State the major agents of chemical weathering and their
respective processes.
(c) Describe any TWO of the chemical weathering processes,
you have identified in (b) in relation to soil formation.
20. (a)State FIVE reasons why farmers should apply organic and
inorganic fertilisers to their crops and field plots.
(b) (i)List FOUR factors that should be considered in
determining the fertiliser needs of crops and soils.
(ii) Discuss any TWO of the factors that you have listed.
(c) What is the meaning of ‘fertiliser ratio’?
21. (a) (i) Explain the meaning of soil erosion.
(ii)
Name TWO natural agents of soil erosion in the
Caribbean.
(b) Explain how farmers use cultural practices, vegetation and
engineering to control soil erosion.
94
6
Section B: Crop production
Plant genetics,
breeding and
biotechnology
By the end of this unit you should be able to:
✔ explain the basic principles of genetic inheritance in plant breeding
✔ explain the role of plant breeding in the development of cultivars
✔ explain the nature and purpose of biotechnology in plant improvement.
Concept map
Principles of genetic
inheritance
Cells
Division
Mitosis
Meiosis
Variation
Alleles
Crossing over
Plant genetics, breeding and biotechnology
Role of plant
breeding
Inherited
characteristics
Dominant alleles
Recessive alleles
Genotype
Phenotype
Homozygous
Heterozygous
Inheritance
in plants
Biotechnology
Use of bacteria to make
disease-resistant plants
Genetic modification (GM)
Mutation breeding
Genetically modified
organisms (GMOs)
Controversy
Other GM technology uses
Test cross / back cross
Monohybrid inheritance
Selection
Hybrid
Germplasm
95
Section B: Crop production
6.1 The principles of genetic inheritance
selective breeding ▶
Understanding how characteristics of organisms are passed from generation to
generation is fundamental to the techniques used in plant breeding. For thousands
of years, farmers have selected crops and livestock with the most favourable
characteristics and used these to produce crops with greater yields and to breed
better animals. This process was known as selective breeding and it produced
results in a relatively short time.
Nowadays, we can change the characteristics of crop plants by introducing new
genetic material. This can improve yields, provide resistance to disease and
increase the nutritional content of the crop.
ITQ 1
Write a definition of selective
breeding.
unicellular, multicellular ▶
The basic structure of all organisms is the cell. Some organisms, such as bacteria,
are unicellular (consist of only one cell). Most organisms are multicellular and
consist of large numbers of different cells organised into tissues and organs.
Cells
cell membrane ▶
cytoplasm ▶
nucleus ▶
cell wall ▶
vacuole ▶
chloroplasts ▶
All cells have the following features:
• a cell membrane surrounding the
living material of the cell
• cytoplasm, which is the living
material of the cell
• a nucleus containing chromosomes.
Plant cells (see Table 6.1) differ from
animal cells in that they have:
• a cellulose cell wall
• a large vacuole (space surrounded
by a membrane) containing cell sap
• chloroplasts containing the green
pigment chlorophyll.
Structure
Cell membrane
organelles, ▶
mitochondria, ribosomes ▶
Cytoplasm
Nucleus
chromosomes, ▶
genetic code, DNA ▶
Cell wall
nucleus
cytoplasm
vacuole
cell membrane
chloroplasts
Figure 6.1 A typical plant cell.
Function
Surrounds the living material of the cell.
Controls the movement of substances into and out of the cell.
Contains many small structures called organelles in which metabolic
activities take place, e.g. mitochondria for respiration and ribosomes
for protein synthesis.
Controls the activities of the cell.
Contains chromosomes, which carry genetic information in the form of
the genetic code consisting of DNA. Each cell of an organism has a
specific number of chromosomes.
Non-living; made of cellulose.
Surrounds the living material and gives the cell a rigid shape and
supports it.
Stores water and dissolved substances (the cell sap).
Organelles in which photosynthesis takes place and food is
manufactured.
Found in leaves and green stems.
ITQ 2
Vacuole
Chloroplasts
Explain what an organelle is and
name TWO organelles in the
cytoplasm of plant cells.
Table 6.1 The functions of plant cell structures.
96
cell wall
6: Plant genetics, breeding and biotechnology
Cell division
cell division ▶
nuclear division ▶
mitosis ▶
meiosis ▶
New cells are formed by cell division. First, the nucleus divides and then the
cytoplasm divides. It is vital that genetic information in the parent cell gets passed
on to the new cells.
There are two types of nuclear division.
• Mitosis: In mitosis, chromosomes in the nucleus of the parent cell divide
into two equal sets so that the nucleus in each new cell has exactly the same
number of chromosomes as in the parent cell. This type of division occurs
when new cells are produced throughout the life of a living organism.
• Meiosis: In meiosis, gametes (sex cells) are formed in the reproductive
organs. The nucleus of each gamete has half the number of chromosomes
as in the parent cell. When fertilisation occurs, the zygote has the correct
number of chromosomes restored.
Variation
alleles ▶
crossing over ▶
ITQ 3
Explain how crossing over may result
in variation.
A gene is a section of a DNA molecule that codes for a particular characteristic,
such as tongue rolling in humans or flower colour in peas. Some people can roll
their tongues, but others cannot. If you inherit one form of the gene, you can roll
your tongue, but if you inherit a different form of that gene you cannot. These
different forms of the same gene are known as alleles. The genes are arranged
in a line along the chromosomes and are always found in the same position on a
specific chromosome. Each chromosome in a pair carries one allele for a particular
characteristic. Both these alleles may be the same or they may be different.
During the first division of meiosis, crossing over may occur, which means
that alleles on one chromosome of a pair may be exchanged for the alleles on
the other chromosome. When the chromosomes separate, there could be new
combinations of alleles on each chromosome. This means that the gametes
produced as a result of meiosis are not genetically identical to the parent cell, and
this in turn gives rise to variation in the offspring. Variation only occurs as a result
of sexual reproduction.
6.2 The role of plant breeding
How characteristics are inherited
variation ▶
dominant ▶
recessive ▶
The characteristics of an organism are determined by the genes inherited from
its parents. The parents may have different alleles of some genes and these may
combine in different ways in the offspring. This gives rise to variation.
To explain how characteristics are inherited, we can use the example of tongue
rolling in humans. A person who can roll the tongue may have inherited one
allele for tongue rolling from the mother and another from the father. But if the
two alleles are different, that is, one for tongue rolling and one for non-rolling,
the person would still be able to roll the tongue because the tongue-rolling allele
is stronger. It is said to be dominant, and its effect will show. The allele for nonrolling is said to be recessive, and will not show if the dominant allele is present.
If two alleles for non-rolling were inherited, then the person would not be able
to roll the tongue.
97
Section B: Crop production
We can show this by using letters to represent the alleles. If the allele for tongue
rolling is R and the allele for non-rolling is r, a person who can roll the tongue
could have the following combinations of alleles: RR or Rr. A person unable to
roll the tongue could have only the combination rr.
genotype ▶
phenotype ▶
homozygous ▶
heterozygous ▶
When we write down the combinations of alleles for a particular characteristic we
refer to it as the genotype as it describes the genetic make-up. So RR, Rr and rr
are all genotypes. Whether the person is a tongue roller or a non-roller is described
as the phenotype: it is the appearance of the characteristic as determined by the
genes.
Tongue rolling is a phenotype and there are two genotypes for this: RR and Rr.
In RR, both alleles are the same. When both alleles are the same the person is
said to be homozygous for the characteristic. The other genotype (Rr) has two
different alleles so the person is said to be heterozygous. A non-roller can only
be homozygous (rr) because both alleles are the same and are recessive.
We can show how these alleles are inherited in the following way.
Let R represent the allele for tongue rolling. Let r represent the allele for nonrolling.
Example A: If both parents are homozygous dominant, RR, then all the children
will be tongue rollers.
Example B: Let us see what happens if one parent (the mother) is RR and the
other (the father) is rr.
Gametes
R
R
r
Rr
Rr
r
Rr
Rr
In this case, the father cannot roll his tongue, but the children will inherit R from
their mother and r from their father. So all the children will have Rr as their
genotype. As R is dominant, they will all be tongue rollers.
Example C: If both parents are heterozygous, Rr, then the children could be rollers
or non-rollers depending on which combination of alleles they inherit.
We can draw a table to show the possibilities.
ITQ 4
Explain the difference between the
following:
(a) genotype and phenotype
(b) dominant and recessive
(c) homozygous and heterozygous.
Gametes
R
r
R
RR
Rr
r
Rr
rr
In both parents, half the gametes will carry the R allele and half the r allele. The
table shows what the genotypes of the offspring could be. There is a 1 in 4 chance
of the offspring being homozygous RR, a 2 in 4 chance of being heterozygous Rr,
and a 1 in 4 chance of being homozygous rr. This can be expressed as a 1 : 2 : 1
ratio.
When we consider the phenotypes, we can see that of the four possible
combinations of alleles, three will be rollers and one will be a non-roller. So the
ratio of phenotypes is 3 : 1.
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6: Plant genetics, breeding and biotechnology
Inheritance in plants
Characteristics in plants are inherited in exactly the same way as shown in the
tongue-rolling example. In pea plants, stem length is determined by a pair of
alleles. Stems can be tall (T) or dwarf (t). If a pure-breeding (homozygous) tall
plant (TT) is crossed with a pure-breeding dwarf plant (tt), then the offspring will
all be tall but heterozygous. This is shown in the next table.
Gametes
t
t
T
Tt
Tt
T
Tt
Tt
If the offspring of this cross are then interbred, a mixture of tall and dwarf plants
will be produced, as shown in the next table.
Gametes
T
t
T
TT
Tt
t
Tt
tt
The ratio of genotypes is TT : 2Tt : tt.
The ratio of phenotypes is 3 tall : 1 dwarf.
test cross, back cross ▶
We cannot determine the genotype of the tall plants by looking at them. If a plant
breeder wants a pure-breeding variety of pea plants, the breeder needs to carry
out a special cross to determine the genotypes of the tall peas. This type of cross is
called a test cross or a back cross. It involves growing the tall peas and crossing
them with dwarf pea plants that have the genotype tt. Figure 6.2 shows this type
of cross.
Back cross on TT plants
Back cross on Tt plants
Gametes
T
T
Gametes
T
t
t
Tt
Tt
t
Tt
tt
t
Tt
Tt
t
Tt
tt
All the plants will be tall
Half the plants will be
tall and half dwarf
Figure 6.2 A back cross or test cross.
ITQ 5
Explain how a back cross or test cross
works.
monohybrid inheritance ▶
Take a look at Figure 6.2. If the plant breeder finds that some dwarf plants grow
from seeds resulting from the back cross, then the parent with the unknown
genotype was heterozygous. But if all the seeds produce tall plants, then the
parents were both homozygous.
Monohybrid inheritance
The cross shown in Figure 6.2 involves a single pair of alleles that code for a pair of
contrasting characteristics. It is called monohybrid inheritance. There are not
many examples of this type of inheritance in humans as most characteristics are
controlled by a group of genes. For example, height is controlled by many genes.
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Section B: Crop production
If you arrange people in your class in a line from shortest to tallest there might be
a big difference between the extremes, but differences between individuals would
be small.
In crop plants, some examples of monohybrid inheritance include flower colour,
seed shape and pod colour in peas, bitter taste in cucumbers and hairiness of
stems in tomatoes.
However, the appearance of a plant depends on environment as well as on the
combinations of its genes. If the growing conditions are not satisfactory and plants
do not get sufficient nutrition, they may not develop properly. For example, if
a plant is deprived of light it will lack chlorophyll, be unable to make food by
photosynthesis and therefore will not grow to its full height.
Selection
selectively bred ▶
The crop plants that we are familiar with have been selectively bred over many
years to develop favourable characteristics, such as larger yields or juicier fruits.
The Scotch bonnet pepper has been selectively bred for its fiery flavour. Farmers
have traditionally saved seed from the best of their crop to sow the next year. In
this way, over a long period, farmers have improved their crops. A good example
of this type of artificial selection is shown by different members of the cabbage
family, the Brassicas (see Table 6.2). A wide range of vegetables have been
selectively bred over many years.
Vegetable
Broccoli
Brussels sprouts
Cauliflower
Cabbage
Kale
Kohlrabi
Special characteristics
Thick stem and green flower head.
Many small lateral buds.
Large white flower head.
Large terminal bud.
Many large leaves.
Thick edible stem.
Table 6.2 Brassica vegetables and their special characteristics, which have been
selectively bred.
Brussels
sprouts
kohlrabi
cabbage
Figure 6.3 Local selectively bred crop
(pineapple).
100
kale
broccoli
Figure 6.4 Some vegetables of the cabbage family.
cauliflower
6: Plant genetics, breeding and biotechnology
Golden apple giant
crossed with dwarf plant,
CARDI, Grenada
Golden apples, Spondias cytherea, are indigenous to the
Caribbean, and are a common fruit tree. The problem with the
golden apple is that the tree was too tall to harvest the fruit
easily, resulting in much of the ripe fruit falling to the ground and
being damaged. The dwarf golden apple is easier to harvest fruit
from, but it produces very small fruit. The CARDI representative
in Grenada crossed the tall and dwarf species, hoping for a larger
fruit that could be picked easily from a short tree. Figure 6.5
shows the tall tree, which has grown low boughs, but still
has fruit that is too high to harvest easily.
Figure 6.5
Golden apple tree, Grenada.
The staple diets of most countries involve members of the grass family. This family
includes rice, maize, wheat, oats, barley, rye and millet. These cereal crops have
been cultivated for thousands of years and the varieties available today are the
result of selection and hybridisation.
hybrid ▶
A hybrid is formed when two different varieties are crossed. The two varieties
are chosen for their desirable characteristics, which the breeder hopes will be
combined in the offspring. For example, if a variety of wheat with short stems
is crossed with a variety that is resistant to drought, the hybrid might have short
stems (making it easier to harvest with less wasted as straw) and also be able to
survive dry conditions. It is not easy to predict the outcomes of such crosses and
plant breeders are continually developing new varieties.
By carefully selecting varieties, plant breeders are able to improve crop plants.
The biggest benefit has been an increase in yields of grain in cereal crops. This
is enormously important for feeding the increasing world population. There is
now much interest in developing disease resistance and drought tolerance in crop
plants.
ITQ 6
Using an example, explain why it
is important to keep seeds of older
varieties of crop plants.
seed banks ▶
germplasm ▶
The major disadvantage to selective breeding is that it reduces variation, so there
are fewer varieties of crop plants. If environmental circumstances change, such as
a change in climate, some of our present varieties might not thrive and it would
be difficult to selectively breed new ones. For this reason, it is important to keep
seeds of older varieties so that these genetic resources are available for breeding
new varieties. Seeds are kept in seed banks, where conditions are controlled
to maintain the seeds’ viability. Collections of plants in botanical gardens and
the preservation of old varieties of fruit trees in nurseries add to the reserves of
genes that could be used by plant breeders. These sources of genetic material
are referred to as germplasm. They are essential for the development of future
varieties of crop plants.
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Section B: Crop production
Practical activities:
1. Grow two different varieties of a crop, such as tomatoes or corn.
(a) Make sure you treat both varieties of crops identically.
(b) Observe the stages of growth and the different characteristics of the varieties.
(c) Draw a table like the one here to help you record observations clearly.
Observations
Variety 1
Date
Variety 2
2. Visit botanical gardens, parks and protected areas. Write down the varieties of plant that are being grown. Research each variety
and suggest the reason why that variety was chosen.
Plant variety
Example: Pride of Barbados, peacock
flower, Caesalpinia pulcherrima
Research
Flowering plant of the pea family.
Sensitive to the cold and will die back when exposed to frost.
Leaves are bipinnate, around 20 – 40 cm long.
Flowers are in groups (racemes) up to 20 cm long, each flower
with five yellow, orange or red petals.
Fruit is a pod 6 – 12 cm long.
Reason chosen
Flowers have bright yellow,
orange or red petals.
6.3 Biotechnology in plant improvement
biotechnology ▶
Biotechnology involves using plant and animal cells and micro-organisms to
produce useful substances. People have used yeast to make beer, wine and bread
for thousands of years. People also use fungi to make cheese, and bacteria to
make yoghurt.
Using bacteria to make disease-resistant plants
genetic engineering ▶
host ▶
Recent knowledge of the structure of DNA has enabled scientists to alter the
genes in the cells of living organisms and to introduce characteristics from another
living organism. This is known as genetic engineering. A gene for a particular
characteristic in one organism can be introduced into another organism, called
the host. For example, a gene for resistance to a certain disease can be introduced
into a host crop plant. When the crop plant is grown, it will not be damaged
should there be an outbreak of the disease.
Scientists can use bacteria to introduce new genetic material into the host cells.
Bacteria are easy to work with and it is possible to insert pieces of DNA carrying
disease resistance into them. When these bacteria enter the host plant they cause
it to produce cells that contain the new DNA. These cells are then used to produce
tiny plants that can be transplanted and that will grow into mature, diseaseresistant plants. The tiny plants will all be genetically identical and they will all
have the gene for disease resistance.
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6: Plant genetics, breeding and biotechnology
There are techniques other than using bacteria that can be used to insert new
genetic material into plants.
genetic modification (GM) ▶
There are other examples of genetic modification (GM) that are used to
improve crops.
• Herbicide resistance can be bred into crop plants. This allows the crop to
be sprayed with herbicide to get rid of weeds and only the weeds will be
destroyed, not the crop (this has been done with soybean).
• Resistance to insect pests can be bred. A gene is introduced into the crop plant
that enables it to make a lethal protein when attacked by the pest. The protein
is toxic to the insect but not to humans or other animals (this has been done
with maize).
• Virus resistance can be added. A gene has been introduced into rice plants,
which then show increased resistance to the rice stripe virus.
• Improved flavour and keeping qualities can be bred. Genetic modification to
tomatoes prevents the softening of tomatoes as they ripen without altering
the flavour and colour.
1. Gene coding for disease resistance is isolated
sticky ends on gene
3. The gene is introduced into the plasmid
gene coding for
disease resistance
4. The plasmid is put back into the bacterium
2. Plasmid is removed from the bacterium
bacterium
bacterium
circular bit of DNA
called a plasmid
5. The plant is infected with the bacterium; in this way
the gene for disease resistance enters the plant
Figure 6.6 Introducing a disease-resistance gene into a crop plant.
mutation breeding ▶
Mutation breeding is the process of exposing seeds to chemicals or radiation
to generate mutants with desirable traits to be bred with other cultivars. Plants
created using mutagenesis are sometimes called mutagenic plants or mutagenic
seeds. Over 230 different crops and plant species have been subjected to mutation
breeding, including various essential crops, such as wheat, rice, grapefruit,
rapeseed, sunflower, cotton and banana. The induced mutant varieties possess
both agronomic and nutritional quality traits that make them the most preferred
varieties on the market. Similarly, numerous cultivars of rice, maize, wheat,
cotton, chickpea and apple that are resistant to different bacteria and viruses have
been released.
genetically modified organism (GMO) ▶
Genetically modified organisms (GMOs) are any organisms whose genetic
material has been altered using genetic engineering techniques known as
recombinant DNA technology. Organisms such as salmon, pigs, cattle and chicken
have been genetically modified to improve milk quality or resistance to particular
diseases.
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Section B: Crop production
Controversy about GM
Research into GM crops continues and the possibilities are extensive. There are
apparent benefits for growers and for food production. However, not everyone
believes that genetic modification is good.
Practical activity:
In groups, research the uses
of GM technology. Create a
poster showing the advantages
and disadvantages of genetic
modifications in food production.
ITQ 7
Explain what genetic engineering is.
ITQ 8
Give THREE examples of genetically
modified crops.
Some of the objections are:
• it is a new technology and the long-term effects are not known
• the effects of eating GM products on human health cause concern
• the modified genes from one species might get into other species
• natural genes can be deleted or ‘turned off’ and other genes may have their
behaviour changed
• GM technology is an expensive process; often the technology is developed by
a large corporation, who charges a lot of money for the GM seeds.
Genetically modified crops are not grown for public consumption until they have
been thoroughly tested. Any research involved in their production is controlled
and the crops undergo extensive field trials. In some countries, food prepared
from GM crops has to be labelled so that the public can choose whether to buy
it or not. As good as improvements in genetically modified organisms seem to
be, there are disadvantages to introducing GMOs into our daily diets: the impact
of GMOs is not known and there have not been any human safety trials. Many
people are concerned that the antibiotic supergene that is within most GM crops
could transfer to humans and create super diseases that are resistant to antibiotics.
Other uses of GM technology
Genetic engineering is used in medicine to produce human hormones, such as
insulin and growth hormone. It is also used to produce the enzyme used in cheese
making (rennin). Traditionally, this enzyme was extracted from the stomachs of
young calves, kids or lambs, but now it can be produced from genetically modified
yeasts.
GM crop Bt maize,
Caribbean
Bacillus thuringiensis maize, or Bt maize, has been
formulated from a donor organism that is a naturally
occurring soil bacterium (Bacillus thuringiensis). The gene
of interest produces a protein that kills Lepidoptera larvae,
in particular the European corn borer. This insect creates
about one billion US dollars of damage to maize crops
every year. The Bt protein is in the proteins throughout the
Bt maize plant; when an insect eats the Bt-containing plant,
the protein is activated in its gut, which is alkaline. In the
alkaline environment, the protein partially unfolds and is
cut by other proteins, forming a toxin that paralyses the
insect’s digestive system and makes holes in the gut wall.
The insect stops eating within a few hours and eventually
starves. Due to misuse of this crop, there are now some
corn borers that are resistant to Bt maize, so this GM crop is
becoming less effective.
104
Figure 6.7
Maize, Trinidad.
6: Plant genetics, breeding and biotechnology
Revision map
Variation results
from the exchange
of portions of pairs
of chromosomes
Only meiosis
produces
variation
Mitosis
Cell division creates
new cells; the nucleus
divides followed by
division of the
cytoplasm
Hybrid –
created by crossing
two different
varieties
Resistance to
insect pests
Meiosis
The alteration
of the genes of
an organism
Disease
resistance
Seeds must be
conserved to create
a reserve of
genetic material
Plant cells
differ from
animal cells
Chloroplasts
and a vacuole
containing
cell sap
Genes that
provide useful
characteristics
Bacteria are
used to insert
pieces of DNA
into host cells
Cell division
and variation
Selective
breeding
Nucleus contains
chromosomes, which
carry genetic information
in the form of the
genetic code made
up of DNA
Improved
flavour
Involves
introducing a gene
from another
living organism
Genetic
engineering
Crop plants
selectively bred to
increase yields or develop
disease-resistance or
drought tolerance
Biotechnology
and GM
Plant genetics,
breeding and
biotechnology
Each chromosome
of a pair carries one
allele for a particular
characteristic
Many people are
concerned about the
safety of genetically
modified crops
Homozygous –
both alleles for a
characteristic are
the same
Genetic
inheritance
Plant cell consists
of a nucleus, surrounded
by cytoplasm, enclosed
by a cell membrane;
cell contents surrounded
by a cell wall
Protection
against
viruses
Inherited
characteristics
Dominant allele
shows even if only
one is present
in an individual
Monohybrid
inheritance – a single
pair of alleles codes
for a pair of contrasting
characteristics
Heterozygous –
two alleles for a
characteristic are
different
Genotype –
the combination
of alleles
Phenotype –
the appearance of
the characteristic
Recessive allele
does not show
if there is a
dominant
allele present
105
Section B: Crop production
Examination-style questions
Multiple-choice questions
Write down the number of the question followed by the letter of the correct answer.
1.
2.
3.
4.
5.
All living cells have:
A cell walls
B chloroplasts
C large vacuoles
D cytoplasm.
Which one of these cell parts is directly involved in cell division?
A Cell membrane
B Nucleus
C Vacuole
D Chloroplasts
If two heterozygous tall-stemmed plants (Tt) are crossed, the ratio of tall : dwarf plants
produced will be:
A 1:1
B 4:0
C 3:1
D 1:3
Crossing over occurs during:
A the first division of meiosis
B the first division of mitosis
C the second division of meiosis
D the second division of mitosis.
In plants, meiosis occurs in:
A the stamens
B the root tips
C the vascular cambium
D the stem tips.
Short-answer and essay-type questions
6.
(a) Describe the process of mitosis.
(b) Give THREE ways in which meiosis differs from mitosis.
7. (a) A farmer was given a sample of seeds from a cross between two tall pigeon pea
plants. Describe how the farmer can find out whether these seeds are pure-breeding
(or homozygous) for tallness.
(b) Explain what is meant by selection. How has it been used to develop different types
of Brassica vegetables?
8. (a) Explain what is meant by genetic engineering.
(b) Describe THREE examples of how genetic engineering has improved crop plants.
(c) Suggest TWO concerns that people have about the production of genetically modified
crops.
9. (a) Outline the steps in the process of introducing new genes into a crop plant.
(b) Explain how this technology can benefit crop production.
10. (a) Explain what a hybrid is.
(b) How are hybrids used to improve crop plants?
(c) Suggest why it is important to keep the seeds of older varieties of crop plants.
106
7
Section B: Crop production
Land
preparation
and farm
machinery
By the end of this unit you should be able to:
✔ explain land preparation methods
✔ discuss the importance and functions of machinery in crop husbandry
✔ describe the safety precautions in the operation of tools, machinery
and equipment
✔ describe the care and maintenance of simple tools and equipment.
Concept map
Land preparation
methods
Site selection
Clearing
Tillage
Drainage
Levelling and
making beds
Land preparation and farm machinery
Machinery
Safe operation
Care and maintenance of
tools and equipment
Seeders
Tools and
equipment
Keeping records
Transplanters
Harvesters
Combine harvesters
Tractors
Two-wheeled
Four-wheeled
Crawlers
Safety gear
Safety devices
Tractor
operations
Maintaining a
knapsack sprayer
Maintaining a
mistblower
SAFE STOP
Attachments
Handling fuels
and chemicals
Attachments
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Section B: Crop production
7.1 Land preparation methods
Land preparation ensures that the soil is well prepared before a crop is planted. It
involves selecting an appropriate site for a crop and selecting the most appropriate
crop for the land available. Land preparation involves clearing, tilling, fertilising
the soil, liming, setting up the drainage, levelling the land and creating the beds.
Site selection
It is extremely important to choose the best site to cultivate a crop. Most farms
have some variation in soil type, topography and shade. It is also useful to consider
the type of crop that was planted previously, as this affects the current nutrient
content of the soil. Selecting a location that requires inputs to prepare the land for
planting will cost the farmer money and time. Understanding the best location for
each crop, or adjusting the cropping decision based on the land available will help
the farmer to create a more efficient and profitable farm business.
Figure 7.1 Hand tiller in use.
Clearing
clearing ▶
ITQ 1
List the equipment needed to
remove trees from abandoned land.
ITQ 2
Describe how bushes, crop residues
and tall grasses are removed from
land mechanically.
Clearing the land is normally the first operation. Depending on what the land
was previously used for, it usually involves removing trees, bushes, shrubs, tall
grasses or crop residues. Areas that have been abandoned and may have become
overgrown with trees and dense foliage may be cleared manually using an axe or
a cutlass, or mechanically using a chainsaw and a bulldozer.
Clearing land of grass, bush and crop residues is done by brushcutting. This can
be done manually using a brushing cutlass, or mechanically using a weed wacker
or a brushcutter attached to a tractor.
When land is bulldozed it is essential to save the topsoil.
Follow this sequence when clearing the land.
• Remove the trees and heap them in windrows.
• Scrape off the topsoil and place it in heaps.
• Grade the land, filling in any depressions.
• Spread topsoil over the entire area.
Tree trunks and twigs, which have been chopped or bulldozed, should be placed
in windrows (heaps) and allowed to decompose. In this way organic matter,
humus and nutrients are released into the soil.
Figure 7.2 A manual brushing cutlass (left) and a brushcutter tractor attachment (right).
108
7: Land preparation and farm machinery
Tillage
tillage ▶
Tillage refers to breaking up the soil surface and incorporating organic matter
into the soil. It is usually divided into two stages: primary tillage, where the soil is
broken up by ploughing, and secondary tillage, which involves refining the soil.
primary tillage ▶
In primary tillage, land that has been cleared is either dug manually with a
garden fork or ploughed mechanically using a tractor. The tractor may be a hand
tractor with a rotary plough or a four-wheeled tractor with a mouldboard or disc
plough.
The effect of primary tillage is to:
• loosen or break up the soil surface
• allow air and water to enter the soil more freely
• bury or mix organic matter with the soil.
Figure 7.3 A tractor with a plough
(primary tillage).
secondary tillage ▶
(a)
(b)
At the end of primary tillage, the soil is in large clods or lumps.
Secondary tillage refers to breaking up large clods of soil into smaller pieces
(or aggregates) and the production of a tilth. The process may be done manually
using a hoe, rake or hand fork or mechanically using a harrow and a rotovator.
(c)
The effect of secondary tillage is to:
• obtain a tilth suited to the crop
• produce a seedbed for the cultivation of crops
• cut up and mix organic matter (crop residues or
stubble) into the soil
• allow the roots of crop plants to penetrate easily
and grow freely in the soil.
Farmers use two main methods of tillage, either
manual or mechanical.
(d)
Manual methods
Commonly used by small-scale farmers.
Can be used on hilly terrain as well as on flat or undulating land.
Require physical strength or physical power.
Laborious, tedious and time-consuming.
May be seriously affected by a scarcity of labourers.
(e)
Mechanical methods
Used extensively by large-scale farmers.
Difficult or sometimes impossible to use on hilly terrain.
Rely on power from machines.
Speedy, effective and economical.
Greatly reduce the need for manual labour.
Figure 7.4 Secondary tillage practices.
Table 7.1 Comparison of manual and mechanical methods of tillage.
ITQ 3
Describe the difference between
primary and secondary tillage.
109
Section B: Crop production
Drainage
drainage ▶
Farmers must set up drainage to remove excess water from the surface and subsurface of the soil, especially during the rainy season. There are many types of
drains and drainage systems (see Figure 7.6). These range from simple channels
to complex systems that can also provide irrigation during the dry season. Drains
may be prepared manually using a fork, spade, hoe, rake and garden line or they
can be dug mechanically using a ridger / banker (see Figure 7.5) and a back hoe.
45-60 cm
1.5 m
15 cm
30 cm
45-60 cm
1.5 m
30 cm
V (vee) drain
box drain
60-90 cm deep
tile drain (underground)
Figure 7.5 A ridger / banker.
1m
trench, canal or storm drain
60-90 cm deep
rubble drain (underground)
contour drains (on hillsides)
Figure 7.6 Some common types of drains.
Levelling and making beds
Practical activity:
Prepare a piece of land for planting
a crop of your choice. The type of
crop to be planted will influence
the amount of preparation needed.
Think about the location of the
crop, and ensure the land is level
with beds made as well as tilled.
After the drains have been dug, the land needs to be levelled to form beds suited
to the crop, soil type, season and weather conditions. During the dry season, flattopped beds may be used. In the rainy season, the beds need to be constructed
so that excess water is removed, especially in areas with clay soil. Cambered
beds have slightly sloping tops. Ridges and furrows create channels for water to
drain away and mounds have raised portions in the centre. The farmer may use
a variety of beds: cambered beds, ridges and furrows, mounds on cambered beds
and ridges and furrows on cambered beds.
flat-topped beds
cambered beds
mounds on cambered beds
ridges and furrows on
cambered beds
ITQ 4
Explain why levelling needs to be
done at the same time that the land
is being prepared for the crop.
Figure 7.7 Some examples of beds.
110
ridges and furrows
7: Land preparation and farm machinery
7.2 The importance and functions of machinery
used in crop husbandry
ITQ 5
Give TWO reasons why machines
have improved agricultural
production.
Despite the global population increasing dramatically in number over the last
70 years, the amount of food being produced has kept pace with this population
increase. Globally, there has been a large decline in the number of farmers around
the world, however, mechanisation and farm machinery have improved, which
saves time in almost every farm enterprise. In much of the Caribbean, there has
been a decline in the number of farmers because of a lack of mechanisation. Young
people view agriculture as labour intensive and for older people, which is why
they are not interested in working in farming. While the opportunity for a growth
of farming enterprises has never been better, in the Caribbean it has become
more difficult for a farmer to run a commercial farming enterprise without the
necessary machinery to be able to compete in the marketplace.
In agriculture, several types of machines are used for tasks such as ploughing,
planting, harvesting, plucking, ear-notching and castrating. New machines are
continually being designed and existing machines are redesigned and improved.
Agricultural machines
1. have changed and
improved agricultural
production, worldwide
2. enable more farm
work to be done,
more effectively,
per day
4. help to reduce the cost
of production and to
increase farm profits
3. enable agricultural tasks
to be done more
efficiently, saving time
and money
5. help to alleviate drudgery,
motivating young people
to take up agriculture as
a career.
Figure 7.8 The importance of machines in crop production.
Seeders
seeders ▶
transplanters ▶
ITQ 6
State TWO advantages of using
a mechanical seeder rather than
sowing seeds by hand.
Seeders, also known as planters, may be of various types. Some consist of drills,
which sow seeds directly onto the soil. Sometimes these drills combine seeds and
fertilisers so that the seeds are planted with the appropriate amount of fertiliser
for the crop. Transplanters are machines that plant seedlings such as tomato,
sweet pepper and rice, or they may plant bulbs, tubers or corms.
The advantage of a seeder is that the seeds are planted evenly and at the required
density. This is a more efficient method than broadcasting the seed. The machines
that can transplant seedlings speed up the operation, saving time and the cost of
manual labour.
Harvesters
harvester ▶
Practical activity:
In pairs, research Turner’s sorrel
harvesting machine. Create a
presentation to show your research
to the class.
There are various types of harvester, each designed to harvest a specific crop.
These machines speed up the process of gathering in a crop, saving time and
manual labour.
The simplest harvesters can be attached to a tractor, for example, the sweet potato
harvester. This machine digs up the tubers, lifting them from the soil and placing
them on a conveyer belt.
111
Section B: Crop production
combine harvesters ▶
Combine harvesters are used for grain
crops such as rice and other cereals. This
type of harvester is self-propelled and cuts,
threshes and winnows the grain, which is
then gathered in trailers and transported
away for storage. Sugar cane can also be
harvested using special combine machines.
Tractors
tractor ▶
The tractor is one of the most useful pieces
of farm machinery. It is mainly used with
attachments such as ploughs, harrows,
cultivators and trailers. A tractor can also
transmit power to attachments (such as
brushcutters, rotovators, fertiliser spreaders
and threshers) by means of the powertake-off shaft.
Type of tractor
Two-wheeled:
e.g. Merry Tiller
Features
• 5 to 10 horsepower (hp) or 3.75 to 7.5 kW engines
mounted on 2 wheels; 2 handles and lever controls.
• Attachments include brushcutter, rotovator, rotary
plough and trailer.
Four-wheeled:
small
• Gasoline or diesel engines; 10 to 20 hp or 7.5 to
15.0 kW; small front wheels; large rear wheels;
pneumatic tyres.
• Attachments include brushcutter, plough, rotovator
and trailer.
• Engine capacity 30 to 60 hp or 22.4 to 44.8 kW.
• Similar features to a small four-wheeled tractor.
Four-wheeled:
medium
Four-wheeled:
large
• Same features as other four-wheeled tractors but
engines have a capacity of 80 to 100 hp or 59.7 to
74.6 kW or more.
• May have additional ballasting for increased grip
in the form of metal wheel grips or spiked metal
wheels.
Table 7.2 Types of tractors.
Figure 7.9 A sugar cane harvester.
Uses
• Suitable for smallholdings from 1 to 2.5 hectares.
• Suitable for tilling light soils on flat or gently sloping land.
• Not suitable for use on steep slopes, rough land or dry clay soils.
• Not difficult to operate.
• Suitable for small farms of less than 2.5 hectares.
• Economical to use with diesel engine.
• Limited in scope for tasks such as levelling and grading.
• Not suitable for long hours on clay soils.
• Suitable for medium-sized farms of 2.5 to 25 hectares.
• Used for mowing, tilling, planting, fertilising, spraying and threshing.
• Economical to use with diesel engine but has higher maintenance costs.
• Suitable for large farms of greater than 25 hectares.
• Greater scope for a range of agricultural operations including ploughing,
grading, levelling and harvesting.
• Higher maintenance costs.
• Requires well-trained and skilful operators.
Tractors
Figure 7.11 A two-wheeled tractor.
Wheeled tractors
• two-wheeled tractors
• four-wheeled tractors:
small
medium-sized
large
Crawler tractors
• bulldozers
• excavators
• graders
• loaders
• harvesters
Figure 7.10 The classification of tractors.
112
Figure 7.12 A crawler tractor.
Figure 7.13 A four-wheeled tractor.
7: Land preparation and farm machinery
crawler tractors ▶
ITQ 7
Name the attachment that would be
needed to plough a heavy clay soil.
tractor attachments ▶
Crawler tractors are more powerful than wheeled tractors and have metal
chain belts on sprockets instead of wheels and rubber tyres. They are suitable
for land clearing operations, site preparation for roads and buildings and the
construction of dams and embankments (levees). They are used where land is
damp and slippery, covered in tree stumps and stubble, and not suitable for the
four-wheeled tractor. These machines are expensive, have high maintenance
costs and require skilled operators. Many farmers find it more economical to hire
such equipment when it is needed for a specific purpose rather than to invest in
a machine that might not be used all year round.
Tractor attachments
Tractor attachments are devices that fit onto tractors. They make agricultural
operations easier, saving time and labour. Table 7.3 summarises the main uses of
each attachment. Harvesters and seeders may be attached to tractors. These have
been described earlier in the chapter.
Name of
attachment
Mouldboard plough
Disc plough
Figure 7.14 A disc plough.
Chisel plough
Rotovator
Harrow
Figure 7.15 A chisel plough.
Brushcutter
Trailer
Fertiliser spreader
Figure 7.16 A mouldboard plough.
Manure spreader
Crop sprayer
Main uses
• Cuts a furrow slice and inverts the soil.
• Primary tillage.
• Buries vegetation and organic matter.
• Rotating discs cut and invert furrow slices.
• Ploughs heavy clay soils, stony soils and soils containing stubble.
• Chisel-shaped tines break up hardpans.
• Broken-up hardpan not brought to surface.
• Referred to as a subsoiler.
• Secondary tillage after land has been ploughed with mouldboard or
disc plough.
• Primary tillage of cultivated land, vegetable plots or rice fields.
• Preparation of seedbeds requiring a fine tilth.
• Cuts up and incorporates crop residues in soil by means of discs
mounted on a frame (disc harrow).
• Breaks up heaps of manure on pasture (tine harrow).
• Secondary tillage.
• Cuts down grass, weeds and herbaceous plants in lawns, pastures,
orchards and field plots.
• Also known as a mower; can be rotary or flail, finger-bar, cutter-bar or
reciprocating.
• Attaches to drawbar of tractor.
• Transports agricultural inputs (planting materials, manure, fertilisers) and
produce.
• May be tipping or non-tipping.
• Broadcasts fertiliser evenly on to pasture or cultivated field plot.
• Can be calibrated to spread the required amount.
• Spreads manure in solid or liquid form (slurry) on to fields or pasture.
• May have rotating shredders.
• Applies pesticides to the soil.
• Pumps from a boom with ‘fan-type’ or ‘hollow cone’ nozzles.
• Can be calibrated to spray the right amount.
Table 7.3 Tractor attachments and their uses.
Figure 7.17 A fertiliser spreader.
Unit 20 on precision farming has further information about machinery and other
hardware.
113
Section B: Crop production
Machete versus mechanised weed walker, Belize
After interviewing the small farmers, Mr Cucul found out that 76% of the
farmers own a Shindaiwa brushcutter and need only six days to clear an entire
orange orchard. He then realised that only 24% of the farmers chop using
machetes, which requires triple the amount of time (21 days) to complete the
job. Just a few days later, Mr Cucul makes his way to Farmers Trading Centre
(FTC) in Spanish Lookout to purchase his Shindaiwa brushcutter.
Equipment used by farmers to chop grasses
Machete
24% (4 farmers)
Shindaiwa Weed Walker
76% (13 farmers)
Figure 7.18 Equipment used by farmers to
chop grasses.
Efficiency of equipment used to chop grasses
Type of equipment
Mr Jorge Cucul, a 44-year-old resident of Pomona village in Belize, owns
20 acres of orange orchard. As a small farmer, Mr Cucul faces numerous
challenges maintaining his farm prior to being able to reap its benefits. One
of these challenges is keeping the grasses that occupy the spaces between
the orange trees low. It is most essential to keep it low during the harvesting
season. He works by himself most of the time, and this requires him to spend
about three weeks chopping at the grasses with a machete. This is not only
time-consuming but also tiring, and would be expensive if he were to pay for
labour. Mr Cucul talked to neighbouring small farmers in his village and they
suggested that he purchase a Shindaiwa brushcutter to make the job easier to
do. As he thinks about buying one, he decides to question every small farmer
in his village who owns a similar-sized orange orchard, to find out how many
farmers own a Shindaiwa brushcutter and how efficient they find the
brushcutter to be.
Shindaiwa
Weed
Walker
6
Machete
0
21
5
10
15
20
25
Duration of chopping (Days)
Figure 7.19 Efficiency of equipment
used to chop grasses.
7.3 Safety precautions when operating tools,
machinery and equipment
In agriculture, safety practices are essential when handling tools, equipment,
machinery, fuels, pesticides and other chemical substances.
Tools and equipment
Each tool or piece of equipment is specially designed for carrying out a particular
agricultural operation. It is therefore important to choose the tool or equipment
best suited to the task. Using the wrong tool can be dangerous.
Figure 7.20 Safety gear worn by someone
using a knapsack sprayer.
114
The following safety practices should be followed:
• Ensure that the tool or piece of equipment is in good condition, with any
handles firmly attached, blades or prongs clean and sharp, and moving parts
oiled or greased.
• Wear the correct safety gear: tall rubber boots, goggles, gloves, overalls and
hard hat where appropriate. Avoid dangling straps or belts and other loose
clothing.
• Control the equipment when chopping, digging, cutting, brushcutting
or weeding.
• Focus on the task while operating the equipment. Stop if you become
distracted.
7: Land preparation and farm machinery
• Place equipment down safely when not in use. Sharp tools should be stuck
upright in the soil so that they are clearly visible, or placed flat on the soil
with their prongs or sharp edges facing downwards.
• Avoid laying tools or equipment on pathways or on heaps of bush where they
could cause injury or be forgotten.
Safety gear
Special safety equipment protects both the operator and the machinery. It may
consist of special gear for use with equipment or safety devices on the machinery.
safety gear ▶
Safety gear includes:
• clothing: overalls that are tough, durable and fireproof
• head gear: hard hat and helmet, often with face shield
• boots: steel-tipped, with non-skid soles
• gloves: leather, fabric or disposable
• safety glasses and goggles: protection from debris
• respirators and face masks: offer protection from fumes, smoke and dust
• earmuffs: offer protection from loud noises.
safety devices ▶
Machinery and equipment may be fitted with safety devices such as:
• safety clips, buttons and bars
• shields, guards and filters
• safety fuses
• colour-coded lights
• an automatic shut-off that stops the equipment if there is a malfunction.
Safety and tractor operations
The driver needs to be trained and wear appropriate clothing (hard hat, steeltipped boots, no loose clothing, straps or belts). The seat should be adjusted so
that it is comfortable and that all controls can be reached easily. The rear-view
mirror should be adjusted correctly. It is important to be aware of slippery areas,
slopes, proximity to services (gas, electricity and water mains), children, farm
animals and pets. If possible, ask for help to keep children and animals out of
the machinery working area. The tractor should be in good condition, with
appropriate tyres at the correct pressure.
SAFE STOP ▶
attachments ▶
Most farm injuries are caused by misuse of tools and equipment. Being run over
by a tractor is a real risk on farms. SAFE STOP is a system to remind all tractor
users to:
• engage the handbrake
• put the controls in neutral
• switch off the engine
• remove the key.
Any operations involving the Power Take-Off (PTO) shaft, where attachments
are hitched to the tractor, are extremely high risk. The PTO shaft rotates between
9 and 16 times a second and can pull someone into the machinery by loose
hair, torn shirt, scarf or tie. Use SAFE STOP before hitching any attachment to
a tractor. Check that the attachment is safely hitched with protective shields and
safety guards in place before operating. When the operation has been carried out,
remember SAFE STOP before adjusting or removing any attachments.
115
Section B: Crop production
Handling fuels and chemicals
ITQ 8
Explain how fuels and chemicals
should be stored on a farm.
Most fuels used on farms are combustible and care has to be taken when they
are handled, used and stored. Gasoline, diesel and kerosene are used to power
tractors, water pumps and generators. These fuels should be stored in special
containers approved by the Bureau of Standards. There should be ‘No smoking’
and ‘Highly flammable’ signs in the storage areas and in areas where the fuels are
handled. Storage areas should be fitted with locks.
Chemicals, such as artificial fertilisers and pesticides, should be handled with care
and stored in a locked cupboard. Store powders on a shelf above liquids to reduce
the risk of liquids leaking onto the powders. Protective clothing should be worn
when chemicals are being used, and all containers should be thoroughly washed
after use. It is important to safely dispose of the washed chemical containers after
use to ensure they do not harm children, livestock or the environment.
Figure 7.21 Storage tanks for fuels and
compressed gas.
7.4 Care and maintenance of tools and
equipment
Tools and equipment should be well maintained so that they will:
• be in good condition when needed for use
• remain serviceable
• last for many years.
Table 7.4 summarises the major practices for maintaining tools and equipment.
Practice
Cleaning
Drying
Sharpening
Repairing
Painting
Oiling or greasing
Storing
Table 7.4
Procedure
Some tools and equipment need to be washed after use, e.g. fork, hoe, cutlass, rake.
Other tools and equipment not soiled with mud may be wiped with a moistened rag, e.g. hammer, saw, secateurs, file.
After washing, tools should be dried with a rag or left in the sunshine.
Tools such as cutlass, hoe, knife, axe and hatchet have blades with sharp cutting edges and need to be sharpened using a
grindstone or a file.
May involve:
soldering, e.g. handles or the rose of a watering can
welding, e.g. broken forks, spades, shovels, rakes
replacing handles, e.g. hoes, cutlass, hammer, spade.
Oil paint applied to the handles of tools helps to protect them, prolonging their serviceable life.
Oil is applied to blades or prongs of tools to prevent rusting; usually done with a rag moistened with oil or an aerosol
lubricant spray.
Joints, springs and other hinged parts of tools and equipment are lubricated using grease or a spray.
Tools should be stored in a special area using tool racks, cupboards and shelves.
To prevent rusting, avoid storing tools close to fertilisers.
Care and maintenance of tools.
ITQ 9
Describe how tools and equipment
should be stored safely.
ITQ 10
Explain how to prevent tools from
becoming rusty.
116
Keeping records
It is essential to keep records of tools and equipment. Such records should include:
• an inventory of all tools and equipment on the farm
• date purchased and cost
• any tools loaned out, together with the name of the borrower, date borrowed,
date returned and the condition on return
• any regular maintenance, such as safety checks.
7: Land preparation and farm machinery
knapsack sprayer ▶
nozzle
lance
shoulder
straps
tank
spray
control
pump
handle
pump
Figure 7.22 A knapsack sprayer and
its parts.
Mistblower ▶
Figure 7.23 Mistblower.
Practical activities:
Maintaining a knapsack sprayer and mistblower
A knapsack sprayer is a piece of manual farm equipment used to spray pesticide
mixtures on crops. It consists of:
• a tank to hold the pesticide
• an adjustable lance with a pressure relief valve to avoid spraying above the
target pressure
• a nozzle attached to the end of the lance for spraying the pesticide
• a pump operated by a pumping handle
• a contoured frame with padded shoulder straps and an adjustable waistband.
To use the equipment, adjust the knapsack so that it fits comfortably, and choose
an appropriate nozzle to give the desired size of droplets. Pour the correct amount
of chemical into the tank and dilute with the appropriate amount of water. Then
screw the tank cover on securely. Pump air into the sprayer tank using the builtin pumping device. The sprayer can then be used to spray the crop thoroughly.
Avoid spraying on a windy day, as the spray can drift back onto the operator or
onto areas that do not need chemicals and so will be wasted. Protective clothing
of spraysuit, facemask, gloves and boots should always be worn. During spraying,
take care to avoid animal pens, wildlife habitats or riverbanks and other water
sources. Further details on using a sprayer and calculating the required amount
of chemical for the area to be sprayed can be found in Unit 22.
Mistblowers are used for the application of insecticides and fungicides in the
form of a mist. They work by creating a fine mist of the chemical so that it can be
blown (away from the operator) onto the plant or tree requiring treatment. The
mist is useful as it can coat the leaves of vines or fruit trees. Mist blowers use less
water to dilute the chemical, so the misted liquid is stronger than the spray from
a knapsack sprayer.
After spraying from either a knapsack or a mistblower, the following procedures
should be carried out.
• The residual air pressure should be released from the sprayer tank using the
air pressure release valve.
• If the farmer correctly calculates the quantity of chemical required, there
should not be much unwanted chemical mixture left. If there is a little, it
should be sprayed out of the tank on the same field that was being treated
with the chemical.
• The sprayer tank should be washed out by rinsing it three times with water.
Do not use detergent as the detergent may combine with the chemical being
sprayed and create a more dangerous compound.
• The filter should be checked for anything that may block the nozzle.
• Clean water should then be sprayed through the system.
• The sprayer should be dried and any parts requiring grease should be
lubricated. Particular attention should be paid to the mechanism that produces
the fine mist from the liquid in the tank. The mechanism consists of a piston,
housing cap, stem, spring, seal and overall housing.
• The sprayer and chemicals should be stored in a cool, well-secured area.
1. Clean and maintain some
simple tools such as a spade,
fork or cutlass.
2. Clean and maintain a
knapsack sprayer, mistblower
or weed wacker.
117
Section B: Crop production
Revision map
Sows
seeds
Provide
warning signs
and do not smoke or
have naked flames
near fuels
Store
gasoline and
kerosene in
the correct
containers
Use tools
and equipment
safely; wear safety
clothing and goggles
when operating
machinery or
spraying
Harvests
crops
Cuts grass
and weeds
Other
specialised
equipment
Land
preparation
and farm
machinery
Prepares
soil for growing
crops
Land preparation
methods
Clears the
land of trees,
shrubs, grasses
and crop
residues
Tillage
Fertilise and lime
land before sowing
if necessary
Ploughs the
soil to break up
the surface
Incorporates
organic matter
118
Prepares a
good tilth for
the planting
Done
manually or
mechanically using
a tractor and
attachments
Spreads
manure
Machinery
makes land
preparation and
other tasks
easier to do
Safety
devices should
be in place and
checked
regularly
Always use
SAFE STOP
with tractors
Sprays
fertilisers and
pesticides
Provide
drainage to remove
excess water
during the rainy
season
Level land and
create beds suited
to terrain and climate
(use cambered beds
in the rainy season)
Keep detailed
maintenance
records
Care and
maintenance
Store tools
in racks, shelves
and cupboards
All tools,
machinery and
equipment must
be cleaned and
maintained
Store
chemicals safely
and wash equipment
after use
7: Land preparation and farm machinery
Examination-style questions
Multiple-choice questions
Write down the number of the question followed by the letter of the correct answer.
1.
2.
3.
The best attachment to use to break up a hardpan is a:
A mouldboard plough
B disc plough
C chisel plough
D rotovator.
A face mask should be worn when operating a:
A crop sprayer
B manure spreader
C fertiliser spreader
D harrow.
Which agricultural equipment would you use to clear shrubs and vines from an area of
abandoned land?
A Rotovator
B Brushcutter
C Harrow
D Plough
Short-answer and essay-style questions
4.
(a) Describe the main features of a medium-sized, four-wheeled farm tractor.
(b) State the major advantages and disadvantages of such a tractor for the farmer.
5. (a) (i) List FOUR types of plough drawn by the farm tractor.
(ii) State the main uses of each of the ploughs named in (i).
(b) Farmer Rose is planning to plough a plot of land (comprising heavy clay soils, corn
stubble and stumps of pigeon pea plants) to cultivate a crop of cabbage. Which of
the ploughs should she use to prepare the soil for planting? Give reasons for your
answer.
119
Section B: Crop production
8
Crop
management
By the end of this unit you should be able to:
✔ cultivate a fruit, root and leaf crop
✔ describe the major cropping systems
✔ discuss the benefits of the cultural practices associated with crop
production
✔ explain the effects of weeds on crop production
✔ identify insect pests and the damage they cause
✔ identify the cause, symptoms and mode of transmission of major crop
diseases
✔ explain the effects of indiscriminate use of chemicals in the environment
✔ recommend the appropriate methods of controlling weeds, pests and
disease management
✔ explain the importance of plant quarantine.
Concept map
Cultivation of crops
Cultural practices
Fruit
Root
Leafy
Moulding
Mulching
Staking
Pruning
Irrigating
Fertilising
Cropping systems
Monoculture
Multiple cropping
Intercropping
Crop rotation
Phased cropping
Strip cropping
Contour cropping
Mixed farming
Cover cropping
120
Crop management
Pests
Insects
Pest and disease
management
Cultural techniques
Chemical control
Biological control
Integrated pest
management (IPM)
Plant quarantine
Diseases
Weeds
Effect
Control
Fungi
Bacteria
Viruses
Mycoplasmas
Protozoa
Nematodes
Cultural methods
Herbicides
Biological methods
Integrated control
Chemicals
Advantages
Eutrophication
Pesticides
Storage
Safe handling
Disposal of containers
Effective management
8: Crop management
8.1 Cultivation of crops
Practical activities:
1. Using the information
alongside, cultivate a fruit,
root and leaf crop.
2. Prepare a business plan for
ONE of the crops cultivated.
Cultivation of a fruit vegetable crop
The crops include tomato, bean, sweet pepper, hot pepper, cucumber and ochro.
Example: Tomato (Lycopersicum esculentum)
Crop varieties: Calypso, Floradel, Cascade, Heatmaster, Gem Pride, Kada, Nema,
Tropic Boy
• Land preparation: Prepare soil to a fine or medium tilth. Dig box drains.
Make raised, flat-topped or cambered beds 1 m wide and 4 m long.
Spread pen manure or compost evenly and then incorporate into the soil.
• Planting material: Harden off seedlings at 3–4 weeks old.
• Planting distance: Transplant seedlings 45 cm apart with 60 cm between the
rows (45 × 60).
• Fertiliser application: If pen manure or compost was not used during land
preparation, this can be applied to each hole at the time of planting
Weed control
• Remove weeds manually by uprooting or with a hoe at least twice: 2–3 weeks
after planting and then three weeks later.
Figure 8.1 Hot pepper.
Pest and disease control
• Mole crickets, slugs and cutworms: Apply a soil insecticide, or molluscicide
sparingly to the specific area.
• Leaf attack by caterpillars and aphids: Mist / spray affected leaves with
an insecticide.
• Leaf miner attack: Mist / spray affected leaves with an insecticide.
• Fungal attack: Spray the specific plants with fungicide.
• Blossom-end rot: Water the soil regularly.
Cultural practices
• Irrigate the crop regularly (twice per day where necessary).
• Stake plants 1–2 weeks after planting or at the time of planting.
When 25–30 cm tall, tie stems to stakes.
• If desired, prune plants by cutting off side shoots.
• Mould plants and till the soil lightly for aeration and weed control.
• Apply mulch in the dry season.
Harvesting: First fruits are ready for harvesting 2–3 months after planting.
Harvest weekly when they are green but mature or when they are becoming red
(ripening). Mature fruits can be recognised by the area beneath the sepals (calyx)
becoming brown.
Post-harvest handling: Place fruits in large wooden trays in a dry, protected
area for ripening.
Marketing: Grade fruits according to size. Package in clean polythene bags for
sale.
Tomatoes are used for salads, stews, tomato ketchup and juice. They are a good
source of vitamins and minerals.
Other fruit vegetable crops include bean, sweet pepper, hot pepper, cucumber
and ochro. Cultivation details vary slightly, particularly with respect to pest and
disease control and harvesting.
121
Section B: Crop production
Cultivation of a root crop
These include sweet potato, cassava and yam.
Figure 8.2 Dasheen.
Example: Yam (Dioscorea)
Crop varieties: White Lisbon, Yellow Lisbon, Cush Cush
• Land preparation: Plough land to a depth of 30 cm and rotovate soil to a
medium tilth. Broadcast NPK (10 : 20 : 10) fertiliser at the rate of 200 g per
square metre (m2) and incorporate into the soil. If necessary, use a broadspectrum insecticide, taking care not to spread it into the field edges or any
water. Form banks or ridges 30 – 45 cm high and 90 cm apart.
• Planting material: Usually small whole tubers are used, or large yams can be
cut into pieces about 150 – 200 g each (mini-set purpose). There needs to be
skin on each piece, otherwise they will not develop.
• Planting distance: Plant tubers at a depth of 7 cm and 30 – 45 cm apart in the
row. There should be 90 cm between the rows. Planting usually takes place in
early May.
• Fertiliser application: Apply NPK (10 : 20 : 10) at a rate of 45 g / plant about
two months after planting. Drill or place the fertiliser in the soil to reduce loss
of nutrients.
Weed control
• After planting, apply a pre-emergent weedkiller, following the dilution
instructions carefully. Later, control weeds by hand weeding or by a shield
between rows.
Pest and disease control
• Caterpillars and leaf-eating pests: Use an insecticide on the affected plants.
• Fungal leaf spots: Use fungicide specifically and in the recommended dose.
• Nematodes: Chemical management is temporary and ineffective so practise
tillage (drying out the soil), good irrigation management to reduce soil stress,
equipment and machinery cleaning between fields, as well as using earlyresistant varieties of crops.
Cultural practices
• Ensure that the field is well drained.
• Stake yams to increase leaf exposure for photosynthesis to improve crop yield.
Harvesting: Harvest yams 9–12 months after planting. Dig out the tubers
carefully using a digging stick, without damaging or bruising yams.
Post-harvest handling: Wash and air-dry the yams, pasting any cut or damaged
surfaces of tubers with ground limestone or wood ash. Store yams in a cool and
well-ventilated room.
Marketing: Grade tubers for wholesaling or retailing.
Yams are boiled and eaten sliced or mashed, or as a porridge and in soups. They
can be processed into a powdered form and reconstituted into ‘instant yam’.
Rejected tubers are fed to pigs. They are a source of carbohydrate with some
vitamins and minerals.
Other root crops include sweet potato, carrot and cassava.
122
8: Crop management
Cultivation of a leafy crop
These include lettuce, cabbage, Chinese cabbage (pak-choi), spinach and seasoning
herbs.
Example: Lettuce (Lactuca sativa)
Crop varieties: Iceberg, Empire, Trinity, Bronze Mignonette, Green Mignonette
• Land preparation: Same as for tomato except that a fine tilth is required.
• Planting material: Harden seedlings at about three weeks old.
• Planting distances: Transplant seedlings 25 cm apart in the row and 25 cm
between rows.
• Fertiliser application: Apply organic mulch around each plant before and
after planting, re-apply when the mulch has dried.
Figure 8.3 Leafy crop.
Weed control
• Uproot weeds as they appear. Light tillage helps to aerate the soil and
control weeds.
Pest and disease control
• Leaf attack by aphids and caterpillars: Apply an insecticide to the affected
plants.
• Fungal attack: Use a fungicide sparingly in the recommended dose.
Cultural practices
• Water or irrigate the crop regularly.
• Lightly dig up the soil surface for aeration and weed control.
• Mulch in the dry season.
Practical activities:
1. Create a portfolio including
details of crop production
activities. Use photographs to
record stages of growth and
crop management.
2. Prepare a business plan and
budget for one of the crops
you grow.
Harvesting: Lettuce heads are ready for harvesting in 4–6 weeks. Cut heads
using a sharp knife and place gently in a large basket with the cut stems facing
upwards.
Post-harvest handling: Remove bottom leaves that are old, blotchy or diseased.
Wash heads carefully and place in trays or baskets. Keep in a cool area and spray
with cold water to maintain freshness.
Marketing: Grade heads according to size. Package in clear, polythene bags for
wholesale or retail.
Lettuce is eaten raw as a salad and in sandwiches. It contains some vitamins.
Other leafy vegetable crops include cabbage, Chinese cabbage (pak-choi), spinach
and seasoning herbs.
8.2 Major cropping systems
cropping system ▶
A cropping system is a way of growing a crop or a range of crops. The major
cropping systems used by crop farmers include:
• monoculture
• multiple cropping or mixed cropping
• intercropping
• crop rotation
• phased cropping
• strip cropping
• contour ploughing
• mixed farming
• cover cropping.
123
Section B: Crop production
Sometimes a combination of cropping systems may be used. These depend on
the land, the size of the farm and the type of crop production. For example, a
mixed farm on hilly terrain might use contour cropping, mixed cropping and
cover cropping.
Monoculture
monoculture ▶
Figure 8.4 Monoculture – sugar cane
plantation.
Monoculture is the continuous cultivation and production of only one crop on a
plot of land for many years. A good example is the cultivation of sugar cane. This
type of system can lead to the build-up and rapid spread of pests and diseases that
attack the crop, for example, froghopper infestations and smut disease in sugar
cane.
Monoculture is a risky business for the farmer because the farmer invests
everything in one crop. Crop failure can result in severe economic loss. However,
some farmers have become specialised in the cultivation of a specific crop, such as
rice, pineapple or pawpaw. The farmer needs to invest in the specific machinery
required for the cultivation, harvesting and preparation for market of a chosen
crop, so it can be more economical for the farm to focus on a single crop. Sugar
cane is a popular monocultural crop, which demands high investment in specific
machinery, for example, a sugar cane combine harvester.
Multiple cropping
multiple cropping ▶
ITQ 1
State ONE advantage and ONE
disadvantage of monoculture.
Figure 8.5 Mixed cropping – lettuce and
tomato.
Multiple cropping (also called mixed cropping) refers to the cultivation of two
or more crops simultaneously on the same plot of land. It is generally practised by
smaller farmers. This type of cropping system provides income on a regular and
continuous basis for the farmer.
The crops are chosen carefully to:
• have a shorter growing period, while others have a longer growing period
• grow to different heights
• have a variety of root systems (deep-rooted and shallow-rooted)
• have a range of water and nutrient requirements.
The benefits of this type of cropping include:
• an improvement in, or maintenance of, soil fertility, irrigation and drainage
• easier management of pest control and a reduction in pest infestations
• easier management of fertiliser application and weed control
• control of soil erosion, as different crops provide different forms of vegetative
cover for the soil
• a smaller risk of total crop failure
• a variety of crops produced
• a reduction in pest infestations.
Crops suitable for this type of cropping are soybean and pigeon pea, root crops
and cereals.
124
8: Crop management
Intercropping
intercropping ▶
ITQ 2
Explain the difference between
multiple cropping and intercropping.
Intercropping is the cultivation of a short-term crop, for example, lettuce,
between the plants of a medium-term crop, such as sweet pepper. It helps the
farmer earn quickly from the sale of the lettuce crop while the main crop of
sweet pepper develops. This is also known as a cash crop. The crops chosen for
intercropping need to be compatible so that one crop does not smother the other
with rapid growth or use all the soil nutrients.
This type of cropping system helps the farmer to use the space between plants of
the main crop more efficiently. Soil fertility is maintained and soil nitrogen may
even increase, particularly if one crop is a legume such as beans. The vegetative
cover provided by two crops helps to control soil erosion on sloping ground.
Crop rotation
Crop rotation is where crops are grown in succession (one after the other) on the
same plot of land. For example, a sequence of tomato, bean (a legume), lettuce
and beetroot helps to maintain soil fertility because the legume crop adds nitrogen
to the soil.
In addition, the inclusion of deep-rooted and shallow-rooted crops helps to use
soil nutrients from different levels. The other benefit is that a build-up of pests
and diseases in the soil is prevented (pests and diseases are usually specific to one
type of crop). See Unit 1.
Figure 8.6 Strip cropping.
Phased cropping
phased cropping ▶
Phased cropping is a system of continuous cropping and harvesting. A plot of
land is divided into four sections. The planting dates are sequenced so that there
is continuous cropping and harvesting of the produce, section by section. In this
way, a farmer can maintain a regular supply of produce to consumers and earn a
steady income over time. This type of cropping prevents an oversupply, or glut, of
one crop, which would have the effect of lowering the price on the market.
Strip cropping and contour cropping
strip cropping ▶
contour cropping ▶
ITQ 3
Explain what is meant by contour
cropping and give ONE reason why
it is practised on sloping land.
mixed farms ▶
Both these cropping systems can be used for the cultivation of crops on sloping
land. Strip cropping refers to planting different crops in strips of varying width
on flat, undulating or sloping land. It is normally used as a soil conservation
measure on slopes. It has similar advantages to multiple cropping.
Contour cropping is another method of conserving soil on sloping land. The
land is ploughed along the contours and then crops are planted. In this way, soil
erosion through heavy rainfall is prevented.
Mixed farming
Mixed farms may be small, medium or large and produce both crops and
livestock. A variety of cropping systems may be used depending on the nature of
the land and size of the farm. Many organic farms (see page 5) are mixed farms.
Cover cropping
cover cropping ▶
Cover cropping is used to improve soil fertility and to prevent soil erosion. It
involves planting a crop that grows rapidly and provides cover on bare soil. The
cover crop is usually planted after the main crop has been harvested and can be
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Section B: Crop production
Practical activity:
Plan a one-year crop rotation
programme using leaf crops,
legumes, root crops and fruit
vegetables, such as tomato.
ploughed into the soil before the land is replanted. The cover crop, often referred
to as ‘green manure’, provides a cover of vegetation for the soil and adds organic
matter when it is ploughed in. If a legume, such as cowpea or vetch, is planted,
then the nitrogen content of the soil is increased. Cover crops may be sown
between the rows of other crops, and are often planted between rows of fruit
trees in an orchard.
8.3 Cultural practices associated with
crop production
Practical activities:
1. Produce a fruit, leaf and root
vegetable crop. During the
sowing, cultivation and growth
of the crop, use appropriate
cultural practices.
2. Create a PowerPoint
presentation on the production
of vegetable crops using your
own notes and photographs.
ITQ 4
Many activities (see Table 8.1) are necessary to ensure the optimum growth of a
crop so that its production is profitable. These activities improve or maintain soil
fertility so that the growth of the crop is maximised. Many of the techniques used
are described in Unit 5.
Cultural practice
Moulding
Procedure
Soil is scraped up and heaped
around the base of a plant to
form a small mound using a hoe
or trowel.
Mulching
Materials such as dry grass,
leaf mould and plastic sheeting
are placed on the soil surface
around the base of the plants.
Staking
A stake is placed beside a
plant; normally 2 m long round
wooden stakes with 30 cm
buried in the ground, are used.
The stem of the plant is tied
to the stake, with nylon twine
looped to form a figure eight
and then wound twice around
the stake before tying securely.
Tying is done at 20 cm intervals
along the stem.
Dry, diseased or excessive
• Improves the shape of the plant.
twigs, leaves and branches of a • Encourages growth and development of
plant are removed using a sharp
fewer, but larger fruits.
• Enables air to circulate more freely in the
knife, a pair of secateurs or a
crop so discouraging fungal diseases.
small pruning saw.
• Prevents spread of diseases to other
plants.
This is applying water to the
• Enables good growth and development.
soil for the benefit of crop
• Prevents crop loss through wilting and
plants. It can be carried out in a
death.
• Helps to regulate supply of soil water
variety of ways.
for crops.
Fertilising is the application of
• Promotes growth, development and
fertilisers to crop plants. Details
production in the crop.
of fertilisers are given in Unit 5. • Produces healthy plants.
• Improves and maintains soil fertility.
What are the benefits of mulching?
Pruning
Irrigating
Fertilising
Benefits
• Covers the roots of plants.
• Aerates the soil.
• Creates root-room for the growth of
lateral roots.
• Gives support and keeps the plant
upright.
• Enables drainage of excess water from
the roots.
• Conserves soil water.
• Adds organic matter and humus if grass
or leaf mould is used.
• Improves soil fertility.
• Controls weed growth.
• Supports plants with weak stems.
• Enables the plant to grow upright.
• Keeps the fruit high above the ground
away from soil contamination.
• Makes pruning, weed control, tillage and
harvesting more convenient.
Table 8.1 Cultural practices involved in crop production.
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8: Crop management
8.4 The effects of weeds on crop production
weed ▶
A weed is any plant that is growing in the wrong place, or where it is not wanted.
This means that any plant can be a weed: the seeds of the previous year’s crop
can produce ‘weeds’ if they germinate in the ground where a different crop has
been planted.
Weeds compete with crop plants for space in which to grow, and for light, water
and nutrients. If weed growth in a crop is heavy, then crop plants are deprived
of their requirements and the yield and quality of the produce will suffer. Weeds
can also contaminate the crop produce with their seeds and fruits. Some weed
species act as hosts for pests (such as aphids) and disease-causing organisms. If
weeds in a crop become infected, then disease-causing organisms can infect the
crop plant and cause damage. Some weeds (for example, redhead) are poisonous
to livestock, especially cattle and horses that may stray onto the fields.
Why are weeds so successful?
Figure 8.7 Nutgrass is a common weed.
Weeds are successful in competing with crop plants because of the following
factors.
• They germinate and grow very rapidly. If conditions are good, they will grow
into large plants producing many seeds. If conditions are less favourable, they
can produce plants that will be smaller but still produce seeds.
• They produce large numbers of seeds under favourable conditions.
• They can often reproduce vegetatively as well as by producing seeds. Those
weeds that produce underground stems or rhizomes can be spread by cultural
practices such as hoeing and tillage.
• The seeds are easily dispersed, often over a wide area. Many weed seeds are
dispersed by wind and can be carried long distances.
• The seeds may remain viable (capable of germination) in the soil for a long
period. In some species of weed, germination occurs when conditions are
favourable. Some weeds will germinate on exposure to light, so they will
germinate when the soil is disturbed by tillage.
• They grow very rapidly in the seedling stages. If they germinate before the
crop seeds, they can grow much more quickly than the crop can and smother
the crop seedlings.
Most of the major weed species belong to just a few plant families: the grasses, the
sedges and the composites, such as railway daisy and red thistle. In the Caribbean,
annual and perennial grasses, vines and woody plants can be problem weeds.
Possible benefits of weeds
In general, weeds are harmful, but their rapid germination and growth on bare
soil provides a cover of vegetation that can help to prevent soil erosion due to
heavy rainfall.
ITQ 5
What is a weed?
In some cropping systems, fields can be left without a crop (fallow) for a growing
season and then weeds are ploughed in before the next crop is planted. The
ploughed-in weeds add organic matter to the soil. In addition, weeds growing
around fields attract beneficial insects, such as bees and insects that prey on
crop pests.
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Section B: Crop production
Practical activities:
1. Collect and identify TEN
common weeds.
2. Conduct a weed control trial.
Grow TWO identical crops
under identical conditions but
allow one crop to become
infested with weeds. Record
your information on the effects
of the weeds’ growth on the
production of the crop.
ITQ 6
Explain when pastures should be
mown to control weed growth.
8.5 Methods of weed control
Weeds within a crop should be controlled to ensure a good yield and good-quality
produce. Methods of weed control include:
• cultural control: adequate preparation of the land and cultural practices such
as hand weeding and hoeing
• chemical control: using weedkillers (herbicides)
• biological control: using other organisms to control weed growth
• integrated control: combining two or more methods that are suited to a
particular crop.
Cultural methods
There are several measures that a farmer can take to minimise the spread of
weeds.
• Buying good-quality seed prevents weeds being sown with the crop. Cheap
seed may be contaminated with weed seeds or other crop seeds. If there are
broken or empty seeds, then the density of crop plants will be affected and
there will be more room for weeds to grow.
• Cleaning tools and equipment after use will prevent weed seeds from
spreading to other crops.
• Crop rotation helps to control weeds. Some weeds are associated with certain
crops so planting different crops in rotation can control a particular weed. For
example, a parasitic weed called Striga affects maize, sorghum and cowpea.
This weed can be controlled by planting different crops in successive years.
• Mulching can control weeds by depriving them of light for photosynthesis and
also preventing the germination of weed seeds.
• When land is cleared, the vegetation is sometimes burned. This has the benefit
of getting rid of annual weeds, but does not destroy the underground parts of
perennial weeds. It also destroys useful soil organisms. Soil may be sterilised
by burning before crop seeds are sown.
• Ploughing will turn the soil over and bury any weeds, but it may also bring
buried weed seeds to the surface where they will germinate and grow before
the crop. Ploughing prepares land for the crop, but it cannot be used to
control weeds in a crop that has started to grow.
• Hand weeding is where weeds are pulled out by hand or by using a hoe. This
is an effective method but it is labour-intensive and time-consuming. The use
of tools may damage onions, potatoes and cassava, and it is not an effective
method against perennial weeds. Care needs to be taken when removing weeds
with herbaceous jointed stems that root easily. Even a small piece left in the soil
can grow. When hand weeding, it is important to distinguish weed seedlings
from the crop seedlings so that there is minimum loss of crop seedlings.
• Mowing is used to control weeds in pastures, lawns and orchards. It needs
to be done when weeds are mature but before they have produced flowers
and seeds.
• Flooding is a method of weed control used in rice fields. It will get rid of
weeds that cannot tolerate being covered in water.
Herbicides
herbicides, selective herbicides ▶
non-selective herbicides ▶
128
Herbicides are chemicals used to kill weeds. They may be selective herbicides,
which kill some plants but not others, or non-selective herbicides, which kill
all plants that they come into contact with. The use of herbicides is a very efficient
method of controlling weeds and saves hours of manual labour.
8: Crop management
The type of herbicide used depends on the following factors.
• The state of the land: If land is fallow, it will need to be treated differently
from land that has been recently used for growing crops.
• The type of crop: The herbicide should not kill the crop so a selective
weedkiller that kills broad-leaved weeds should be used on a cereal crop,
such as maize or sugar cane.
• The type of weed: Some selective herbicides kill broad-leaved weeds and
others kill grass weeds.
pre-emergent herbicides ▶
post-emergent herbicides ▶
post-maturity herbicides ▶
contact herbicide ▶
systemic herbicide ▶
The stage of growth of the crop: Some herbicides are applied before the shoots of
the crop grow above the ground (pre-emergent herbicides). Some herbicides
are applied after the shoots have emerged (post-emergent herbicides) and some
when the crop is mature and ready for harvesting (post-maturity herbicides).
Non-selective herbicides
Some herbicides may be applied to soil to kill all the weeds present before the crop
is planted. These herbicides are usually non-selective and the land is ploughed
or harrowed after the application. Glyphosate and Paraquat are herbicides used
in this way and they control annual weeds. Paraquat is a contact herbicide.
When it comes into contact with the leaves, it interferes with photosynthesis by
destroying the cell membranes. Glyphosate is a systemic herbicide and works
within the plant. Paraquat is classed as ‘moderately toxic’ by the World Health
Organization (WHO) as it can negatively affect humans and the environment. It
should be used sparingly, with proper precautions and exactly as instructed by the
manufacturer.
Selective herbicides
Selective herbicides are used once the crop has been planted. A systemic herbicide
is used; this is taken up from the soil by weed seedlings and carried within the weed
to the growing regions where it produces its effect. Sometimes weed seedlings
absorb the herbicide through the leaves. Atrazine, Alachlor and Metolachlor are
systemic herbicides that kill grass weeds. All three of these pesticides are known
to contaminate groundwater because of their mobility and persistence in soil, so
they need to be used with caution. Atrazine and Alachlor have been banned by
the European Union because of their toxicity levels. Metolachlor has been classed
a possible human carcinogen (cancer-causing agent) in the USA so it should be
used sparingly and full personal protective equipment (PPE) should be worn
when preparing solutions and spraying.
ITQ 7
List FOUR factors a farmer needs to
consider before applying a herbicide
to a crop.
Precautions
When spraying crops with herbicides, protective clothing needs to be worn and
safety precautions need to be taken to prevent spillage runoff and contamination of
other areas. All the instructions provided for correct application must be followed.
If spraying is on a large scale, then weather conditions need to be considered. It is
also wasteful to spray if there is a high wind or heavy rainfall.
Biological methods
biological methods ▶
Biological methods of weed control involve the use of other living organisms to
control the weeds. Here is a list of some biological methods.
• Cover cropping: In this method, a legume crop such as mung beans or
cowpeas, is used to provide vegetative cover. This has been described on
page 125. It prevents the growth of weeds and also adds nitrogen to the soil
when the crop is ploughed in. The disadvantage is that the farmer has to
purchase the legume seeds.
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Section B: Crop production
ITQ 8
Explain how the plant density of the
crop can affect weed density.
ITQ 9
Explain what is meant by integrated
control.
integrated control ▶
Practical activities:
1. Practise different types of weed
control in vegetable production,
keeping a record of which type
of weed control is the most
effective. Remember to leave the
correct time interval between
spraying and harvesting the
vegetables (to prevent chemical
residues in the produce).
2. Herbicides are being improved
constantly. Research the
development of TWO new
herbicides. Check the advantages
and disadvantages with suppliers
and extension officers, and also
find out what the conditions of
use are for the two chemicals.
• Planting density: The density of the crop affects the growth of weeds. The
higher the density of the crop, the less room there is for the weeds. The
density should be adjusted so that crop plants can develop fully but there is
little room left for weeds. If the crop density is too high, the plants will be
small and the yield will be less.
• Choice of crops: Low-growing crops, such as sweet potatoes, and broad-leaved
crops that spread quickly, such as melons and zucchini, cover the soil surface
and prevent the growth of weeds.
• Grazing: Sheep and goats can be used to clear weeds from pastures.
• Introducing a pest of the weed species: This involves using an insect pest or
a disease that affects the weed. This method needs to be carefully controlled
and it is not suitable on a small scale. For example, adults of the Longitarsus
jacobaeae beetle (the ragwort flea beetle) attack ragwort plants and cause
extensive damage. The beetle larvae also attack the plant by feeding on the
roots of this poisonous weed.
Integrated control
Different methods of weed control may be used at different stages of crop growth.
Integrated control means using a combination of control methods. The use of
non-selective herbicides and ploughing may be the best treatment during the
preparation of the land before the crop is sown. Once the crop is at the seedling
stage, hand weeding can be effective on small plots, which avoids the use of
chemical sprays. The choice of herbicides depends on the type of cropping system
in use, particularly as herbicides effective for one vegetable crop are not effective
against another.
8.6 Pests and crop damage
A variety of pests (mainly insects) cause damage to crops but there are also other
animal pests.
• Rodents, such as rats, damage growing crops and stored crops. Rats are serious
pests of sugar cane. They gnaw through the stems, which make the plants fall
over and allows bacteria to get into the damaged stems.
• Birds feed on fruit crops such as grapes, mangoes, papaya and banana. They
also damage the young seedlings of vegetable crops.
• Mites, which belong to the same major group as spiders, feed on the leaves of
crop plants.
Insect pests
vectors ▶
Insects damage plants in different ways.
• The adults and larvae may feed on the crop.
• The adults may lay eggs inside flowers, fruit or stems. When the eggs hatch,
the larvae often feed on the leaves and bark, for example, treehoppers on
apple trees.
• Insects may act as carriers (vectors) of viral diseases (for example, aphids).
Insects can be divided into two feeding groups:
• biters and chewers
• piercers and suckers.
The biters and chewers, such as beetles, grasshoppers, crickets, ants, bees and
wasps, eat their way through plants, leaving holes in the plants. The larvae of
butterflies and moths (caterpillars) and flies (maggots) are also chewers. By
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8: Crop management
destroying leaves, these insects reduce the amount of food that the plant can
make by photosynthesis. This results in poor growth and decreased yield. Often,
a severe infestation can destroy the whole crop.
Practical activity:
Collect insects and put them into
groups according to whether they
have biting, chewing, piercing or
sucking mouthparts.
Sucking insects, such as aphids, have piercing mouthparts that suck sap from
inside the soft tissues of the plants. This process results in reduced growth in the
plant. The adult stages of flies and moths are also sucking insects.
Table 8.2 shows some common insect pests of food crops.
Insect pest
Aphid
Example
Effect on crop
Sucking mouthparts
damage shoot tips of
crops, e.g. citrus trees,
peppers, eggplants.
Can transmit viral
diseases.
Insect pest
Termite
Fruit moth
Pierces fruits, which
then drop from trees
before they are ripe,
e.g. citrus trees,
cashews.
Weevil
Fruit fly
Bores into fruits before
they ripen, e.g. mango,
pineapple, avocado
pear, guava.
Diamondback
moth
Whitefly
Pierces soft tissues so
plants do not grow or
thrive, e.g. tomatoes,
peppers.
Can transmit viral
diseases.
Flea beetle
Cricket
Chews on shoots of
young plants, often
destroying the whole
plant, e.g. tomatoes,
onions.
Example
Effect on crop
Feeds on the roots and
stems, often destroying
whole plants,
e.g. grapes.
Larvae tunnel into
the corms and cause
a lot of damage by
weakening the plants
so that they are easily
blown down.
Leaves turn yellow and
die, e.g. banana root
borer on bananas.
Larvae (caterpillars)
feed on leaves of
vegetables, e.g.
cabbage, pak-choi,
cauliflower.
Feeds on leaves leaving
round holes, so that
plants have reduced
growth, e.g. ochro.
Can transmit viral
diseases.
Table 8.2 Common insect pests of food crops.
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Section B: Crop production
8.7 Major crop diseases
pathogenic organisms ▶
Crop diseases can be caused by a number of different organisms. These organisms
are called pathogenic organisms (disease-causing organisms). The organisms
enter plants through damaged tissue, the stomata on leaves, or by insects feeding
on plants. Once inside the plant, a pathogen causes an infection. It deprives the
plant of nutrients and water and produces visible signs (symptoms), such as
yellowing leaves and wilting.
Types of pathogen
Fungi – organisms
that do not possess
chlorophyll; consist
of a network of fine
threads that spread
throughout the plant
absorbing nutrients;
usually produce masses
of spores.
Figure 8.8 Smut on maize – caused by a
fungus.
Figure 8.9 Bacterial wilt disease on
bananas – caused by a bacterium.
Practical activity:
Identify plants suffering from
diseases in your local area. Make
a table of each plant you find,
identifying the disease and noting
the symptoms and organisms that
caused it. Include a sketch of the
diseased area.
ITQ 10
Describe the diseases caused by
nematodes.
Mode of
transmission
Spread by spores in the
air, which land on the
plant, germinate and
enter via the stomata.
Bacteria – microscopic,
single-celled
organisms; obtain their
nutrients from the host
plant; multiply rapidly
inside the host.
Spread from plant
to plant in the air, in
rain or from contact
with other organisms.
Enter the plant via the
stomata or wounds.
Viruses – very small
structures; consist of
nucleic acid surrounded
by a protein coat;
reproduces only inside
the cells of the host;
cannot survive for long
outside another living
organism.
Mycoplasmas – tiny
organisms that are
smaller than bacteria.
Spread by aphids and
other sucking insects
(see Table 8.2). Some
may be spread through
budding and grafting of
fruit crops.
Protozoa – small,
single-celled microorganisms; have a true
nucleus surrounded by
a nuclear membrane
(eukaryotic).
Protozoa diseases are
not totally understood.
They are thought to
be spread via vectors
(carriers) , e.g. insects
with a proboscis.
Nematodes – very
small (about 1 mm in
length), non-segmented
worms.
Abundant in the soil.
Can penetrate and
enter roots.
Spread by leafhoppers
that jump from one
plant to another.
Table 8.3 Some major crop diseases.
132
Symptoms of disease
• Rusts form reddish patches on the stem and
leaves of cereal plants.
• Smuts form black powdery masses of spores
that affect the cereal grains.
• Powdery mildews produce a white powdery
coating on the surface of plant leaves and
fruits. Plants become distorted and inedible.
Affects many plants.
• Potato blight destroys the leaves, stems and
tubers of the potato plant.
• Damping-off disease of the seedlings of the
cabbage family causes the collapse of the
stem tissue.
• Bacterial wilts produce symptoms similar to
nitrogen deficiency (leaves go yellow). Can
affect bananas.
• Fireblight causes the blossom and young
shoots of fruit trees to die thus preventing
fruit formation. Affected areas look
blackened and shrivelled.
• Mosaic diseases cause leaves to develop
patches or stripes of colour. Affect a variety
of leafy crops, e.g. tobacco, bodi beans.
• Leaf curls cause distortion and curling of
leaves, e.g. sweet potato leaf curl, which
affects sweet potatoes and tomatoes. (Some
leaf curls can be caused by fungi.)
• Cause yellowing and stunting of plants.
• Leaves become wrinkled and wilted, e.g.
‘bunchy top’ in pawpaw. (These organisms
cause diseases that are less of a problem
than those caused by fungi, bacteria or
viruses.)
• Cause hartroot or lethal wilt in coconut palm.
Symptoms include root rot, browning leaves,
nut fall and plant death.
• Cause phloem necrosis disease in coffee.
Symptoms include yellowing, drooping
leaves and can result in root die-back and
tree fatality.
• Cause swelling of roots and root galls
(lumps), which weaken plants and reduce
growth. Nematodes affect citrus trees,
bananas, pineapples, grapes and tomatoes.
8: Crop management
8.8 Chemicals in the environment
Figure 8.10 Diffuse pollution in a river.
There is widespread use of chemicals in the form of pesticides, weedkillers
and artificial fertilisers. Although they are useful for food production, they are
damaging our environment. Chemicals applied to the soil or sprayed onto crops
can run off fields with the rainwater, flow into rivers and eventually into the
oceans. This causes pollution and affects plant and animal life in both freshwater
waterways and the oceans. Chemicals may also build up in organisms (such as
shellfish). When these animals are eaten, it is thought that the chemicals travel
up the food chain. Chemicals become concentrated in wildlife and often kill the
animals.
Advantages of using agricultural chemicals
Figure 8.11 An algal ‘bloom’ – oxygen
levels will be reduced in the water.
• The effects of applying agricultural chemicals may be seen relatively quickly.
Pests and weeds can be destroyed before they cause too much damage to the
crop.
• Using chemicals results in improved crop yields. Crops benefit from the
removal of weeds and pests and will grow better. Farmers make more profit
and there is a better supply of good-quality produce for the consumer.
• Pest and weed control is quicker and less labour-intensive than manual and
cultural methods. The farmer who uses chemicals has more time for other
operations.
• There is a longer storage life for food. Better-quality produce will be produced,
which will last longer.
Disadvantages of using agricultural chemicals
deoxygenated ▶
eutrophication ▶
Eutrophication
Artificial fertilisers, such as NPK fertilisers, get washed from farm lands into rivers.
The increase in nitrates and phosphates in a river increases the growth of algae.
This creates an ‘algal bloom’ in the surface layers of the water, which blocks
sunlight reaching aquatic plants. When the algae die, they are broken down by
bacteria that use up oxygen in the water. Because artificial fertilisers increase the
amount of algae and bacteria in the water, the water becomes deoxygenated
(lacking in oxygen). As a result, other aerobic organisms in the water, such as
insects, insect larvae and fish, will suffocate and die.
This enriching of nitrates and phosphates in the water is called eutrophication.
Eutrophication can also occur if there are sewage spills or there is a runoff from
farm manure, as these sources contain nitrates and phosphates.
Pesticides
Pesticides can also get into waterways, either as drift from crop spraying or from
being washed off fields by rain. The toxicity of pesticides and their effects on crop
plants have to be thoroughly investigated before the pesticides can be marketed.
Sometimes, the chemicals produced when the pesticides break down may affect
organisms in the environment. Often long-term environmental effects are
unknown until a pesticide has been used by farmers for a while. Once the longterm effects are understood, countries may ban the use of a pesticide.
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Section B: Crop production
DDT (an insecticide)
Dichlorodiphenyltrichloroethane, usually called DDT, is an example of how a pesticide can affect other organisms.
This is a contact insecticide that was used successfully for years to kill a range of insect pests, including mosquitoes.
It had low toxicity to humans, so it was safe to apply to food crops, but it took a long time to break down in
the soil. In the 1960s, DDT and compounds derived from DDT were found in a range of organisms, including
humans. Unfortunately, DDT had entered the food chain. DDT had seeped from the soil into rivers and been
absorbed by small organisms. These organisms were then eaten by larger organisms, eventually getting
into the bodies of the top carnivores. It was found that DDT accumulated in the organisms at the top
of the food chain. For example, some birds of prey started to produce eggs with very thin shells.
The eggs failed to hatch and there was a decline in the numbers of these birds. The use of
DDT was banned worldwide in the early 1970s.
ITQ 11
Explain what is meant by
eutrophication and why it causes
problems to the environment.
Since the problems with DDT, there have been more investigations into the
long-term effects of pesticides. Research has concentrated on the development of
chemicals that break down more readily and are more ‘mobile’ in soil and water.
In addition, new pesticides are being developed to target specific pests.
Safe handling of chemicals and chemical containers
Pesticide labelling is now enforced by law. Labels must contain the following
information:
• the product name or the trade name
• the type of pests it will control
• a list of the active ingredients and their amounts; the official chemical names
must be included and often the common names will be given as well
• the percentage of the inert (inactive) ingredients; inert ingredients do not
need to be listed by name
• the quantity of the product in the container
• the name and address of the manufacturer
• a registration reference to indicate that the product has been tested for use
• an indication of the toxicity
• precautionary statements about keeping the product away from children, as
well as emergency and first-aid treatment
• reference to physical, chemical and environmental hazards
• directions for use
• storage instructions.
The directions for use should be followed carefully as they will indicate:
• where and when the pesticide can be used
• how much to use
• how it needs to be mixed
• safety equipment to be worn and safety precautions to be followed when
applying the pesticide
• how long after application the crop can be harvested.
Storage of chemicals
Agricultural chemicals should be stored in a locked container. Ideally, chemicals
should be ordered only to use, so there should not be a large quantity of half-used
bottles in the store. Powders should be stored above liquids, as powders will not
leak down into chemicals below, creating new and potentially more dangerous
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8: Crop management
compounds. There should be a suitably sized plastic tray for mixing chemicals in
the store. If a pesticide spills as it is being diluted, the spill will be contained in the
plastic tray. This protects the environment, is less hazardous to the farmer, and the
chemical can then be transferred back into the bottle or sprayer tank, thus saving
the farmer money.
Disposal of chemical containers
Triple rinse empty containers with water, draining them into the equipment
used for applying pesticide. Rinse the foil seals too and put them inside their
containers. Firmly replace the caps on the containers immediately. Store the
rinsed and drained containers upright in a secure, weatherproof area away from
stored pesticides (either in a separate store or a separate part of your chemical
store) until you can dispose of them safely.
Safe disposal can be done in different ways. A contractor or distributor can take
back properly cleaned empty containers. The containers need to have been
cleaned either by rinsing them manually at least three times or by using a pressure
rinsing device. They can be disposed of at a licensed waste-disposal or wasterecovery site. If none of these options are available, the empty containers should
be burned. This should be done on a site well away from the chemical store. Full
PPE should be worn while burning containers.
Effective management of pesticides and chemical waste
Reducing the use of pesticides will also reduce the amount of waste pesticide and
the number of empty containers produced. It will also save money.
Practical activities:
1. Find examples of pesticide
labels and interpret the
information on them.
2. Using the information on
storage found on pesticide
labels, design a chemical
store for a farm. Make sure
you include hazard signs and
provide reasons for choosing
to store chemicals in a
certain way.
Consider these questions before you use pesticides.
• Do I need to use the pesticide and, if I do, can I reduce its use?
• Do I have suitable pesticides currently in stock and can I order less new stock?
• Have I chosen the most suitable pack size?
• Can I manage and control the use of pesticides any better?
• Can I use any of the following methods to reduce packaging waste and reduce
the washings produced?
• Soluble packs
• Returnable containers
• Closed-transfer systems
• Flushing systems for low-volume sprayers
• Direct-injection systems
• Round down calculations of the amount of pesticide needed when filling
the sprayer so that you can dispose of the washings on an under-dosed area.
8.9 Pest and disease management
Plants can be protected from pests and diseases in a number of ways involving
cultural techniques, chemical and biological control, and integrated pest
management (IPM).
Cultural techniques
These cultural techniques can be used.
• Removal of pests by hand: This is time-consuming but effective for caterpillars
on cabbages. It avoids the use of toxic chemicals, which could contaminate
the produce, but it is difficult to carry out for most pests.
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Section B: Crop production
• Disinfection and sterilisation of the soil: This technique kills weed seeds,
insect eggs, larvae and fungal spores. Banana corms can be disinfected with
hot water.
• Destruction of any infected plants or produce: Citrus trees infected with a
virus can be burned.
• Crop rotation: This reduces the spread of insect pests that infect specific crops.
• Planting disease-resistant varieties of crop plants: This prevents or reduces
infection. Disease resistance can be selectively bred and many varieties of crop
plants are available (see Unit 6).
Chemical control
pesticide ▶
A pesticide is a chemical substance used to control pests. It is poisonous (toxic)
to the pest but does not harm the crop. Pesticides are classified according to the
type of pest they control and include herbicides (to kill weeds), insecticides (to
kill insects), fungicides (to kill fungi) and nematicides (to kill nematodes). Some
naturally occurring insecticides, such as pyrethrum and nicotine, have been in
use for hundreds of years, but many newer artificial chemicals are now in use.
Pesticides can also be classified according to the way in which they work.
contact pesticides ▶
• Contact pesticides are sprayed onto crops to coat the plants. Contact
fungicides treat fungal diseases and are absorbed by the fungal pathogens.
Contact insecticides get into the bodies of insect pests through their respiratory
systems. These pesticides do not persist for long on the crop plants because
they may get washed off by rain or irrigation, so they have to be reapplied to
control the pest. They are relatively cheap and effective. Examples include
organochlorines (DDT is one of these), pyrethroids and carbamates. These
pesticides disrupt the cellular functions of organisms and are thought to affect
human cells in a carcinogenic (cancer-causing) way.
• Systemic pesticides are absorbed through the leaves and roots of crop
plants and are translocated (moved) around the plant. The cell sap becomes
toxic to the pest, which is destroyed as it feeds on the crop. The advantage of
systemic pesticides is that they remain in the plant for a long time and can
protect the crop from possible infestations before they occur. Examples are
organophosphates and some carbamates. There is evidence that carbamates
cause neuro-behavioural effects in humans and exposure to this pesticide
increases the risk of neurological conditions such as dementia.
• Residual pesticides are sprayed on the land before a crop is planted.
They kill weed seedlings, fungal spores, insect eggs and larvae. They have a
relatively long-lasting effect, although heavy rainfall will cause leaching. They
may be used as part of the land preparation operations undertaken before
sowing or planting. Most residual pesticides have their effect through direct
contact with the pest.
• Non-residual pesticides work instantly but then disappear. The most
obvious ones are insect sprays, which need to make contact with the insects to
kill them, but then disperse very quickly.
systemic pesticides ▶
residual pesticides ▶
non-residual pesticides ▶
Biological control
biological control ▶
136
Biological control relies on the natural predators or parasites of the pest organism.
For example, ladybirds and hover flies feed on aphids, birds eat caterpillars and
fish eat insect larvae. The term is usually used to mean the deliberate introduction
of one species (the predator) to control another species (the prey). The pest is
eaten by the predator.
8: Crop management
Integrated pest management of the sweet potato weevil,
advice from CARDI
In the Caribbean, two weevil species, Cylas formicarius elegantulus (Summers) and Euscepes postfasciatus (Fairmaire), are
serious pests of sweet potato. Both adults and larvae feed on sweet potato tubers and stems. The main damage is caused by
the tunnelling and feeding of the developing larvae, which hatch from eggs laid on or near the surface of exposed roots.
In some Caribbean countries, the incidence of sweet potato weevil is so high that over 60% of the tubers are unmarketable
because of the ugly tunnels, the presence of larvae and a bad smell and bitter taste when the tubers are cooked. The life
cycle of both species takes place throughout the year and can also continue in stored sweet potatoes. Unfortunately, there
are no reported varieties that are resistant to weevil attack and farmers have noticed that the weevils prefer the sweeterfleshed varieties.
Integrated pest management
• Choose short season or ‘early’ varieties (those that produce marketable tubers at around 3½–4 months) and those that
produce tubers deeper in the ground and not close to the soil surface.
• Use crop rotation for at least three seasons.
• Harvest the tubers in weevil-infested soils on time to reduce the length of time weevils can attack.
• Practise good field sanitation before crop establishment and after crop harvest. This will reduce the amount of plant
material available for the weevils during the period between crops.
• Use pest-free stem cuttings taken from the tips of sweet potato vines to establish the crop.
• Practise ‘hilling’ or moulding up the soil in the root zone of the developing vines to cover any exposed
roots and tubers. Close up cracks in the soil to stop adult weevils easily reaching exposed roots and tubers
to lay eggs.
• Trapping adult weevils using commercially available pheromones can frequently be seen as part of
IPM on the larger sweet potato plots in the Caribbean to control the Cylas sp. The pheromone is
a synthetic version of the sex pheromone produced by female Cylas sweet potato weevils. The
traps are designed to hold the pheromone lure and allow entry to the weevils, which are
then killed when they fall into soapy water at the bottom of the trap. Pheromone
formulations for trapping the Eucepes sp. are not yet commercially available.
• If necessary, apply appropriate insecticides where there is a severe problem
that cannot be managed by cultural and mechanical techniques.
Practical activities:
1. During your cultivation of
a vegetable crop, use TWO
appropriate methods to control
pests and diseases. First, you
need to find out what the
common pests and diseases
are and investigate the best
ways to control them.
2. Research crops that can deter
insect pests and make a poster
to share with your class.
Biological control is mainly used against insect pests. Other examples of this
predator-prey relationship include:
• the control of rabbits in arable crops and pasture by introducing the
myxomatosis virus
• the introduction of the Argentinean moth borer to control the growth of
prickly pear on grazing land
• the control of malaria by the introduction of fish to eat the mosquito larvae
• the control of stem borer in sugar cane by introducing wasps from India,
Apanteles flavipes and Paratheresia, and the Cuban fly, Lexophaga.
The most successful use of biological control has been in the protection of
greenhouse crops, where conditions are controlled and the pest insects and their
predators are contained in an enclosed area. The aim is to control the pest but
not eliminate it totally as this deprives the predator of food. The numbers of pest
insects and predators will change but the level of infestation is kept low. This type
of control has been used to protect cucumbers, tomatoes and other salad crops.
Whitefly, a cucumber pest, is easily controlled by the tiny wasp Encarsia formosa.
137
Section B: Crop production
Natural predators of insects are often found on vegetation bordering field plots.
The predators can be encouraged by leaving the edges of fields uncultivated.
Sometimes, strips of uncultivated land are left within field plots. These are
referred to as ‘beetle banks’ and they provide a habitat for insect predators. These
measures often mean that less pesticide is needed.
Integrated pest management
integrated pest management ▶
ITQ 12
Explain the principles involved in the
biological control of pests.
Integrated pest management aims to control pests by using a combination
of methods to keep pest populations at low levels rather than totally eliminating
them. IPM uses cultural and biological control methods instead of relying solely
on chemicals.
If pesticides are used, they should be chosen for their short-term toxicity so that
they break down into harmless substances in a short amount of time. They should
not be used over a long period as the insect pests could develop resistance to
them. Developing pesticides is expensive, so relying only on pesticides will cost
the farmer more money than integrating cultural and biological control methods.
8.10 The importance of plant quarantine
alien pests, alien diseases ▶
Practical activity:
Visit a plant quarantine station.
Alien pests and alien diseases are pests and diseases that do not occur naturally
in a country. Their introduction into a country can cause widespread damage.
With an increase in world trade, much agricultural produce is now exported
and imported. In most countries, strict regulations ensure that only the highestquality pest-free produce is exported and that all imported goods are inspected.
The introduction of alien pest species, such as weeds and insects, can cause havoc
to agricultural production in island territories such as the Caribbean. There may
be no natural predators for the pests, so they could spread rapidly and damage
crops. Imported plant material can carry viruses and it would be dangerous if such
material were to be used for plant breeding.
To avoid these problems, plant quarantine centres have been established by the
Ministry of Agriculture at airports and ports and employ qualified personnel
to inspect agricultural products. Each territory in the Caribbean has its own
regulations and operates its own quarantine centres.
South American palm weevil
The South American palm weevil is an alien species that was first identified in
Trinidad in the 1920s. The palm weevil is a vector of the red ring nematode. This
affects the palm tree by disrupting the water and photosynthesis pathways. The
problem with the weevil is the larvae, which evolved to affect damaged or cut
plant tissue. It takes only 30 beetle larvae to kill a whole palm tree. The only way
to get rid of both the weevil and the nematode is to cut down the tree and burn
the wood. Unfortunately, farmers think it is a temporary problem and leave the
tree standing. If the beetle goes through a full life cycle, the females will fly to the
next tree and infect it. The presence of red ring nematodes emits pheromones that
attract more weevils. A pheromone has been developed to trap the weevils but it is
expensive and the trees need bait servicing. Despite the pheromone method and an
aggressive spray programme, the weevils are still a problem in Trinidad.
138
Figure 8.12
Healthy palm tree.
8: Crop management
Revision map
Mulching
Staking
Chemical –
contact, systemic
and selective
herbicides
Pruning
Integrated –
combination of
several methods
Moulding
Fertilising
Irrigating
Multiple /
mixed
cropping
Monoculture
Any
plant growing
where it is
not wanted
Weeds
Cropping
systems suit
the land and
size of farms
Intercropping
Crop
rotation
Crop
management
Agricultural
chemicals
Pesticides
have to be labelled
and include safety
precautions that should
be followed when
applying them
Many insect
pests also carry
viral diseases
Crops
damaged by
animal pests (rats,
birds), insects
and mites
Insect pests –
biters, chewers,
piercers,
suckers
Pesticides
should be stored
appropriately; containers
should be disposed of
correctly to minimise the
effect on humans and
the environment
Cultural
Integrated
(combination of methods
but with the emphasis
on minimal use of
chemical pesticides)
Crop diseases –
caused by fungi,
bacteria, mycoplasmas,
viruses, protozoa,
nematodes
Pests
Control of
plant diseases
Chemical
Many seeds,
which may spread
over a wide area and
remain viable in the soil
for long time
Pests and
diseases
Pest and
disease
management
Foreign pests
and diseases could
seriously affect crop
production
Biological
Biological –
cover cropping,
planting density,
crop choice, grazing,
introducing a pest
of the weed
Deprive crop
plants of space,
sunlight, water
and nutrients
Phased,
strip and
contour
cropping
Plant
quarantine
protects a country
from pests and
diseases being
brought in
Weed
control
Grow
quickly
Cultural
practices used
to get best yield
and keep soil
fertile
Cultural –
using quality seeds,
cleaning equipment,
rotating crops, mulching,
burning, weeding,
mowing, flooding
Environmental
issues
Toxic chemicals
can get into food
chains and damage
organisms
Can cause
eutrophication
of waterways and
harm wildlife
139
Section B: Crop production
Examination-style questions
Multiple-choice questions
Write down the number of the question followed by the letter of the correct answer.
1.
2.
3.
4.
5.
6.
7.
8.
The cultivation of selected crops in succession on the same plot of land is known as:
A mixed cropping
B intercropping
C crop rotation
D phased cropping.
Soil can be conserved on sloping land by:
A contour cropping
B intercropping
C phased cropping
D monoculture.
Mulching is a cultural practice that:
A prevents the spread of diseases to other plants
B supports plants with weak stems
C aerates the soil
D improves soil fertility.
Which of the following statements about weeds is true?
A Seed germination is slow.
B Small numbers of seeds are produced.
C Seeds remain viable for a long time. D Seedling growth is slow.
Which of the following methods of biological weed control is selective?
A Introduction of a pest species
B Grazing
C Cover cropping
D Planting density
Viral diseases can be spread to crop plants by:
A moth larvae
B aphids
C termites
D weevils.
Mosaic diseases of crop plants are caused by:
A fungi
B bacteria
C viruses
D nematodes.
Eutrophication is caused by the over-use of:
A fertilisers
B insecticides
C herbicides
D lime.
Short-answer and essay-type questions
9.
(a) Describe the FOUR benefits of crop rotation.
(b) Describe a one-year crop rotation programme using leaf, legumes, root and fruit
crops, explaining your choice of crops.
10. (a) Describe FOUR cultural practices associated with crop production.
(b) For each practice, explain the benefits to the farmer.
11. (a) What is a weed?
(b) Explain why weeds are so successful in competing with crop plants.
12. Give an account of the cultural methods used to control weeds.
13. (a) Distinguish between selective and non-selective herbicides.
(b) Discuss the factors involved in deciding which herbicide to use on a crop.
14. Give an account of the methods used to control pests and diseases in crop plants.
15. (a) What is meant by plant quarantine?
(b) Explain why there are strict regulations about the importation of plant material into
the Caribbean.
140
9
Section B: Crop production
Harvesting
and postproduction
management
By the end of this unit you should be able to:
✔
✔
✔
✔
Concept map
Harvesting crops
identify when crops are ready to be harvested
recommend the appropriate harvesting techniques for crops
explain post-harvest handling procedures for various crops
explain the importance of preserving crops.
Harvesting and post-production management
Harvesting methods
Post-harvest handling procedures
Post-harvest management
Signs of maturity
Natural
Post-harvest technology
Perishable
Timing of harvest
Mechanical
Harvest and post-harvest
(ornamentals)
Preservation
Methods
141
Section B: Crop production
9.1 Harvesting crops
Signs of maturity
The useful and edible parts of crop plants are harvested at the desirable stage of
maturity, which varies according to the type of crop.
Maturity is related to the age of the crop. It may be associated with:
• changes in colour
• stems and leaves drying up
• characteristics linked with marketability, processing and use.
mature ▶
Figure 9.1 Harvested bodi beans.
Some crops are harvested at the fully developed or mature stage. This is recognised
by the farmer, who inspects the crop looking for specific signs.
The following list describes the signs of maturity in various crops.
• Tomato: Fully mature stage – browning in the region of the calyx
• Yam, eddo: Fully mature stage – dieback or drying of the aerial stem and
leaves
• Avocado, guava: Fully mature stage – changes in skin colour from dark green
to yellowish-green in guava; avocado changes skin colour to dark green when
fully mature, and brown / black when it is rotten (overripe)
• Banana for export: Should only be 75% mature (or they will overripen
in transit)
• Bodi beans, ochro, loofah: Snap stage
• Cucumber, spinach: Succulent (juicy and not too fibrous) stage
• Green coconut (water nut): Soft / medium jelly stage
• Melon, pawpaw, pumpkin, citrus, hot pepper: Ripe or ripening stage
• Paddy (rice), corn (maize), coconuts: Dry stage
• Eggplant, gourd: Soft, plump stage
The timing of harvesting
Figure 9.2 Sweet peppers ready to harvest.
ITQ 1
List the FOUR major factors that
determine the timing of harvesting.
142
The timing of harvesting depends on several factors.
• The age of the crop: This can be calculated using the date of planting. The
age serves as a harvesting guide for the farmer. The period from planting
to harvesting for some crops can be relatively short (Minetto lettuce takes
4 weeks, cabbage takes 3–4 months). For other crops the period is much
longer (bananas take 9 months, cassava takes 6–12 months depending on
the cultivar).
• The type of crop: Some crops, such as lettuce, dry-corn and rice, are harvested
all at once, enabling the farmer to plant a new crop. Tomatoes, bodi beans,
ochro and hot peppers produce fruit continually for a period, even after
the first harvest. These crops need to be harvested regularly when the new
produce reaches the desirable stage of maturity.
• Time between harvestings: The time between successive harvestings varies
according to the crop. Some examples are ochro 2–3 days, bodi beans 4–5
days, spinach 6–7 days and karale 5–7 days.
• Weather conditions: Cool weather is favourable for harvesting lettuce,
pak-choi, cabbage, cucumbers, sweet peppers and beans. Sunny weather
reduces the moisture content in crop produce and ripens grains, which
makes harvesting rice, corn and sugar cane easier to do. Dry weather makes
harvesting operations using machinery easier to do as the soil is dry.
9: Harvesting and post-production management
9.2 Harvesting methods
Harvesting methods used vary according to the crop and the cropping system
under which it was grown. All methods should be carried out carefully to ensure
that the produce (plant part) being harvested is not damaged.
Manual harvesting is used for cocoa, coffee, bananas and yams. Mechanical
harvesting, using combine harvesters, is used for rice, corn and sugar cane.
Manual harvesting methods
These methods include picking by hand, uprooting, using a knife or a cutlass and
digging out with a fork. These methods are used for crops grown in small plots,
crops grown in multiple cropping or intercropping systems and where crops are
in fields that are not accessible to machinery.
Figure 9.3 Tractor transporting harvested
sugar cane.
ITQ 2
State THREE manual methods of
harvesting and give examples of
crops that are harvested using each
method.
Crop
Ochro
Bodi bean
Tomato
Corn (maize)
Eggplant
(melongene)
Yam
Pawpaw
Banana
Manual methods (see Table 9.1) include:
• nipping-off with the thumb and index finger: bodi bean, cucumber, karale,
hot pepper, string bean
• uprooting and trimming with cutlass and knife: cassava, radish, carrot
• digging out with fork, spade or luchette: yam, sweet potato, ginger, cassava
• cutting off, with pedicel (fruit stalk) and calyx (sepals) attached, using
secateurs: Portugal orange, mandarin, sorrel, ochro, eggplant (melongene),
sweet pepper
• cutting stalks with a sickle and threshing the grains: rice (paddy)
• cutting stalks with a cutlass: sugar cane
• picking by hand: tomato, mango, guava, citrus, maize
• picking with a cocoa knife or rod: cocoa, breadfruit, breadnut
• using a fruit-picker: avocado.
Stage of maturity
• Snap stage: tip end snaps or breaks easily
• When 10 – 15 cm long (average)
• Snap stage
• Prominent indentations on pods
• Brownish around the calyx (sepals)
• Light golden-coloured grains
• Soft, plump fruits
• When 25–35 cm long (average)
• Drying or dieback of aerial stem (vine) and leaves
Method of harvesting
• Cut pedicel (flower stalk) with a sharp
knife or secateurs.
Timing of harvesting
Every 2 – 3 days
• Nip off pedicel using thumb and index
finger.
Every 5 – 7 day
• Hand pick fruits carefully.
• Break or pluck cobs off the corn stalks.
• Cut pedicel with a sharp knife or
secateurs.
Every 5 – 7 days
3 – 5 day intervals
Every 5 – 7 days
• Dig out tubers.
• Ripening of fruit
• Yellowish green or orange-green colour
• 75% developed fruits
• Cut pedicel with a sharp knife or
secateurs.
9 – 10 months after planting
by mid-April; before
sprouting
6 – 9 months after planting;
every 5 – 7 days
• Cut off hand (bunch) with a cutlass.
• Dehand using a sharp knife.
8 – 10 months after planting
Table 9.1 Stages of maturity, methods of harvesting and timing of harvesting for some crop plants.
Practical activities:
1. Harvest the crops planted in the practical activity suggested for Unit 8 (page 126) using appropriate methods. Remember to record
the yields of the harvested crops for your records.
2. Hold an open day to market the produce grown.
143
Section B: Crop production
Mechanical harvesting methods
ITQ 3
State THREE crops that can be
harvested mechanically.
ITQ 4
Explain why some crops are harvested
using machines.
Machines for mechanical harvesting speed up the process of harvesting a crop. This
saves time and manual labour. The simplest types of machines can be attached to
a tractor, such as the sweet potato harvester, or combine harvesters can be used,
such as for grain crops. Mechanical harvesting methods are common on large
farms where fields are easily accessible. However, harvesting machines are often
heavy and are difficult to use on hilly terrain or in poor weather.
9.3 Post-harvest handling procedures
Post-harvest technology
Post-harvest technology refers to processes developed to handle, store and market
produce after it has been harvested. An understanding of the way in which crops
ripen, the changes that take place after harvest and the correct way to store
produce will all increase farm profits.
Figure 9.4 Sugar cane harvesting using a
harvesting machine.
ITQ 5
Describe what post-harvest
technology is.
Poor crop handling after harvest causes a loss of produce that has taken time,
labour and materials to cultivate. There is usually less wastage if produce is grown
and consumed locally, as there is less time for deterioration. However, if produce
has to be transported any distance, losses have to be factored into farm budgeting.
Post-harvest technology needs to be applied if fresh produce is grown far from
where it is consumed.
The following techniques can help to ensure high-quality produce.
• Harvest early in the morning or late in the evening and when the weather is
cool or cloudy.
• Take care not to damage produce with hands or tools when harvesting.
• Pre-cool the produce. This should take place as soon as possible. Care should
be taken to keep produce out of the sun by covering it.
• Cold-water sprays can keep produce fresh, and cool conditions will slow
ripening and prevent dehydration.
• Pack carefully to prevent bruising and damage. Avoid rough handling during
packing, loading and unloading.
• Use large baskets, trays and crates for packing.
• Prevent movement during transportation by securing containers firmly, as
movement can damage and bruise the produce.
• Store produce at the recommended temperature. Perishable produce (produce
that spoils quickly) needs refrigerated storage and transportation.
• Long-term storage of cereals and other produce needs to be under the correct
conditions to prevent damage by pests.
Harvest and post-harvest practices for ornamentals
The harvesting of fruit and root crops, as well as leafy vegetables, is covered in
Unit 8. Ornamental crops need special harvesting techniques and post-harvest
treatment to ensure they reach the market in prime condition.
Figure 9.5 Anthurium lily.
spathe ▶
spadix ▶
144
Anthurium (Anthurium genus)
Depending on their size at planting, suckers produce flowers in three to six
months. Hybrids may produce 12 flowers per year. Flowers are harvested when
the spathe (the hood-like leaf surrounding the spadix) is fully open, the flower
stalk is firm up to the bloom and the spadix (candle) is firm and rough with
prominent seed buds. The blooms are cut with stalk lengths of 40–80 cm using
secateurs, and then placed upright in baskets.
9: Harvesting and post-production management
Post-harvest handling: Flowers are stored in a cool area and graded according to
size, colour and injury. They are then packed in boxes.
Heliconia (Heliconia genus)
Heliconia plants produce blooms nine months after planting. They are cut using
secateurs and placed in baskets. The flower stalks may be of varying lengths.
Post-harvest handling: Blooms are taken to a cool area where they are graded and
then packed in boxes.
Ginger lily (Hedychium genus)
Using secateurs, blooms are cut off together with two leaves on the flower stalk.
The blooms are placed in a basket with flowers protruding upwards.
Figure 9.6 A ginger lily flower.
ITQ 6
Explain why cut flowers should be
kept cool.
Practical activity:
Visit flower shows or farms where
ornamentals are grown. Ask about
the post-harvest treatment of the
blooms that are grown.
perishable ▶
ITQ 7
State TWO precautions that should
be taken to avoid damage or bruising
to produce after harvesting.
Practical activity:
Carry out post-harvest handling
techniques on crops that have been
produced and harvested.
ITQ 8
Describe THREE benefits of postharvest management.
Post-harvest handling: Cut flowers are placed with their basal ends in buckets,
which have been half-filled with clean water, in a cool place. Blooms are later
graded and placed in boxes for export, or into small bundles of six, and covered
with clear polythene for the local market.
Orchid (Orchis genus)
Orchid blooms are cut using secateurs. Sprays are cut with as long a stem as
possible, including some buds and flowers. Blooms are placed in a basket and
transported quickly to the storage area.
Post-harvest handling: Cut flowers may be placed in special orchid tubes filled with
water to support the stems. They are packed in boxes and stored in a cool place.
9.4 Post-harvest management
Post-harvest operations can only maintain but not improve the quality of the
produce. Most fresh produce is highly perishable, which means that it will decay
quickly. Harvested produce generates heat through respiration and loses moisture
rapidly, causing wilting and shrivelling. Rough handling bruises the produce and
it can decay, releasing unpleasant odours.
Post-harvest management:
• extends the shelf-life of produce
• allows more time for transportation, storage, processing, marketing and use
of produce
• allows the produce to be sold to markets further away
• brings satisfaction to both consumers and producers.
The consumer wants good-quality, fresh produce that is clean and will not
deteriorate quickly. Urban and peri-urban farmers can supply such produce
directly to the markets or sell their produce at roadside stalls. Produce may be
trimmed to remove brown, dirty or wilted outer leaves, washed to remove soil,
and graded before being packaged by the farmer into perforated polythene bags.
Polythene bags help to retain moisture and improve presentation for the customer.
Farmers without immediate access to a market will have to sell produce to a
wholesaler or a retailer. Trimming, washing and grading is usually carried out
by the farmer, but the wholesaler or retailer may package the produce. Fresh
produce on sale in shops and supermarkets has a limited shelf-life, so it is stored in
a cool place before being displayed. Often it is packaged to retain freshness and to
avoid too much handling, which could affect the quality. Consumers may prefer
their guavas, sapodillas and mangoes to be of uniform size, so similar-sized fruits
are often packaged together.
145
Section B: Crop production
Banana exports, Dominican Republic
Around 11 306 tons (588 882 boxes) of bananas are exported from the Dominican Republic every week. The bananas are
harvested green and unripened to last the 3–4 weeks it will take to transport them to grocery stores in the USA and
Europe. Following harvest, they are processed by being broken into bunches, labelled with a small origin sticker, then
boxed to protect them during shipping. They are transported by ship in temperature-controlled holds. This type of
post-harvest care prevents the bananas naturally releasing ethane gas, which causes ripening. The presence of a
few ripe bananas can make the rest of the bananas ripen too, as well as other fruits being transported. Once at
their destination port, they are visually inspected carefully, their temperature measured, the peel removed and
the bananas’ flesh colour and texture evaluated. They are then placed in pressurised rooms, which force
air through the banana boxes, ripening the fruit consistently. The temperature of these rooms can be
controlled to speed up or slow down the ripening process. Ethane gas is then used to ripen the bananas
before they are sent by truck to the shops. Bananas are a favourite fruit around the world, and while
much of their flavour is lost through this type of harvesting and post-harvest practice, it is the only
way to get the fruit around the world without them going rotten.
Figure 9.7
Figure 9.8 Banana packaging, showing country of
origin, Dominican Republic.
Bananas on a tree.
Preserving crops
preservation ▶
Preservation prevents the growth of micro-organisms such as bacteria and fungi,
which cause decay and spoilage. It also prevents food from deteriorating through
oxidation or through enzyme activity within the cells of the food.
Preservation may change the texture, taste and appearance of the food, but
microbial decay is prevented or reduced. Short-term preservation keeps food fit
for consumption for days or weeks. Long-term preservation lasts for months or
years.
Micro-organisms can be killed by heat, or their growth can be slowed down by
low temperatures or lack of water (dehydration). Enzyme activity in cells is also
affected by temperature and the presence of water. Oxidation can be prevented
by the exclusion of air.
146
9: Harvesting and post-production management
Preservation method
Refrigeration
ITQ 9
Freezing
Explain why it is better to freeze
fresh vegetables quickly.
Practical activities:
1. Visit a food processing plant.
2. Develop a processed product
from the crops that have been
cultivated. Follow careful
harvesting and post-harvesting
procedures and then preserve
the crop using one of the
techniques.
3. Visit the local Bureau of
Standards; gather information
on the main export for your
country.
Drying
ITQ 10
Explain what happens when fruit is
dried or dehydrated.
Freeze-drying
Preservation technique
• Many vegetable crops are grown
to provide fresh produce. Storing
food in a refrigerator kept at
1 °C to 4 °C will keep it fresh
for several days.
• The freezing process turns water
in the tissues of the food to
ice. The formation of ice draws
water out of the tissues and
they become dehydrated.
• Freezing is carried out as quickly
as possible so that large ice
crystals do not form and damage
the tissue cells. The temperature
inside the food may need to
reach – 5 °C or lower before ice
crystals form.
• The frozen produce is packaged,
labelled and stored at – 20 °C in
a freezer for months.
• Drying can be carried out by
leaving fruit, vegetables and
herbs in the sun. This is a
traditional method used to dry
plums, sorrel, green mango (cut
into strips), grapes, herbs and
peppers.
• The fruits are spread on trays
and turned occasionally to
promote rapid and even drying.
• Drying can also be done by
forcing heated air over the food.
• In this process, food is first
frozen and then ice is converted
to water vapour by sublimation.
To carry out this process, the
food is frozen and then placed
in a vacuum. The ice crystals
are converted to water vapour
without becoming liquid. The
vapour re-condenses to ice on
metal plates provided for the
purpose. This technique works
well with fruit and vegetables.
• The vacuum is broken and
atmospheric pressure is restored
by adding nitrogen gas, which is
chemically inert.
• The products can then be sealed
in airtight packages and do not
need to be refrigerated.
Preservation reason
• Low temperatures slow the
activity of micro-organisms.
• The low temperature needed for
the process reduces the activity
of micro-organisms and may
destroy some of them.
• The temperature also stops
chemical reactions inside cells
as the enzymes are inactivated.
• Drying or dehydration removes
all water from foods to prevent
decay. The activity of microorganisms stops when the water
level inside cells is low.
• The micro-organisms are not
killed and their activity will
resume when the food is
rehydrated.
• The quality of freeze-dried food
is good. The texture may change,
the taste remains the same.
• Freeze-dried foods are
convenient as they do not take
up much space.
Table 9.2 Preservation methods.
147
Section B: Crop production
Revision map
Tomato
Melon
Yam
Some crops,
such as lettuce,
are harvested in batches;
others, such as tomatoes
and beans, produce fruit
continuously over
a period of time
Cucumber
Intercropping
systems
Some crops are
harvested at the
ripe or fully
mature stage
Age of
the crop
Should be done
when it is cool,
early morning or
late evening
Small
farms
Weather
Rice
Sugar
cane
Manual or
mechanical
Other
cereals
Hand
picking
Mechanical
Maturity
of new
produce
Combine
harvesters
Harvesting
methods
Harvesting
crops
Occurs when the
edible parts of plants
are at a desirable stage
of maturity; this varies
with the crop
Harvesting and
post-production
management
Rough handling
during any stage
of post-harvest
operations should
be avoided
Freeze-drying
involves the removal
of ice from frozen food
by sublimation
Refrigeration
Prevents the
growth of
micro-organisms
Keeps food
fresh for
a few days
Heliconia
Drying removes
water from food and
thus prevents the growth of
micro-organisms, it can take
place outdoors in the sun or
by forcing heated air
over the food
Keeps
produce
cool
Shorten
the time taken
for harvesting
Harvesting
methods have to be
adapted to the crop,
the farm and
the terrain
Ornamental
crops need special
post-harvest treatment
to keep them in prime
condition for the
market
Post-harvest
handling
procedures
Post-harvest
management
Freezing can
preserve food for long
periods by keeping it at
very low temperatures,
but it does not destroy
micro-organisms
148
Vegetable
plots
Digging up
roots
Type
of crop
Factors
influencing
the timing of
harvesting
Cutting stalks
with a knife
Post-harvest
technology refers
to processes which have
been developed to handle,
store and market
produce after
harvesting
Blooms are cut
with secateurs and
kept cool to prevent
wilting
Anthurium
Ginger lily
Gives more
time for
processing
Profit for
the farmer
Prolongs
shelf-life
Gives more
time for
transport
9: Harvesting and post-production management
Examination-style questions
Multiple-choice questions
Write down the number of the question followed by the letter of the correct answer.
1.
2.
3.
Sunny weather is best for harvesting:
A tomatoes
B sugar cane
C beans
D sweet peppers.
Mechanical harvesting is usually used to harvest:
A corn (maize)
B radishes
C citrus
D melons.
Harvested produce loses most water through:
A photosynthesis
B translocation
C respiration
D evaporation.
Short-answer and essay-type questions
4.
(a) List FOUR factors that affect the timing of harvesting crop produce.
(b) Discuss TWO of the factors you have listed for (a).
(c) Complete the table.
Crop
Stage of
maturity
Method of
harvesting
Timing of
harvesting
Ochro
Bodi bean
Yam
Banana
5.
6.
7.
8.
(a) List THREE techniques used in post-harvest handling.
(b) Describe in detail ONE technique you have listed for (a).
(c) Describe the techniques farmers should adopt in the post-harvest handling of
tomatoes.
Using examples, give reasons for the use of harvesting machines.
Describe how you would prepare blooms from a named ornamental for market.
A farmer wants to grow tomatoes, beans, pumpkins and cucumbers on a small plot of
land. Describe:
(a) the tools that he would need to harvest these crops
(b) the precautions he would need to take during harvesting
(c) the post-harvest processes needed for these vegetables.
149
Section C: Animal production
10
Introduction
to animal
sciences
By the end of this unit you should be able to:
✔ list the breeds of each class of animals commonly reared in the Caribbean
✔ state the purpose for which the different breeds of animals are reared
✔ list the species of fish and bees.
Concept map
Introduction to animal sciences
Breeds of farm
animals
Uses of different breeds
of farm animals
Cross-breeding
Roles of animals
Supply of raw materials
Pets
150
Species of fish
and bees
Common species of
fishfor farming
Common species of
bees used for farming
10: Introduction to animal sciences
10.1 Breeds of farm animals
Several classes and breeds are reared in the Caribbean (see Table 10.1).
Class of farm
animal
Cattle
Pigs
Goats
Sheep
Rabbits
Poultry
Breeds in use in the Caribbean
Dairy: Jersey, Jamaica Hope, Holstein
Beef: Jamaica Black, Charolais, Zebu, Buffalypso
Landrace, Large White, Duroc, Hampshire, Tamworth
British Alpine, Anglo Nubian, Saanen, Toggenburg
Barbados Black Belly, Blackhead Persian, West African, Virgin Island White
Flemish Giant, New Zealand White, New Zealand Red, California, Chinchilla
Layers: White Leghorn, Rhode Island Red, Bevan Brown, Hyline or hybrid crosses
Broilers: Vantress Cross or other hybrid crosses, e.g. Peterson, Shaver
Table 10.1 Classes and breeds of farm animals reared in the Caribbean.
ITQ 1
Name THREE breeds of dairy cattle
and THREE breeds of beef cattle.
cross-breeding ▶
ITQ 2
Suggest a breed of poultry for
egg production.
Practical activity:
Visit a farm to sketch or photograph
the different breeds of animal.
Draw up a table to note the
differences between them.
Many breeds have been brought to the Caribbean from other parts of the world.
These breeds have been chosen for the quality of their meat or other products,
and also for their ability to tolerate the climate, together with resistance to pests
and diseases.
Some breeds have been developed especially for the Caribbean region by crossbreeding, which is when two different breeds are mated. The breed of cattle
called Jamaica Hope was developed in Jamaica by crossing Zebu cattle from India
with Jersey cattle from Europe. The resulting breed is a good milk producer and is
resistant to some diseases. Similarly, Jamaica Red and Jamaica Black cattle were
developed from Aberdeen Angus cattle for good meat production. In Trinidad
and Tobago, the Buffalypso was developed by crossing different breeds of river
buffaloes. The resulting meat is of a higher quality than the top cuts of prime beef,
and breeding stock has been exported to other Caribbean countries. Barbados
Black Belly sheep are reared for their meat and were likely derived from sheep
brought by settlers to the islands. They tolerate heat and have coats of coarse
hair, not wool, which evolved from crosses of African hair sheep and European
woollen blends.
Neo-tropical animal (wildlife)
production, utilisation and
conservation programme, Sugar Cane
Feeds Centre, Trinidad
At the Sugar Cane Feeds Centre in Trinidad, a project to breed indigenous species
and consider them for domestication is underway. A number of indigenous wild
animals have now been bred in captivity to understand the needs of these animals
if they are to be domesticated for farm business. The research investigated their
housing and environmental needs, feeding and nutrition, reproduction and genetics,
as well as the marketing and socioeconomic role these animals would play should they
be bred for food. The animals that are being researched include the Red Brocket deer
(see Figure 10.1), Capybara, Agutti and Lappe.
Figure 10.1
Trinidad.
Red Brocket deer,
151
Section C: Animal production
Figure 10.2 A Zebu bull.
Figure 10.3 A Jamaica Hope cow.
Figure 10.4 A Jamaica Black cow.
10.2 Uses of different breeds of farm animals
Major roles of farm animals
Figure 10.5 A Jamaica Red bull.
Farm animals fulfil these roles.
• They provide food.
• They supply power for ploughing (bullock, buffalo, mule) and transport
(mule, donkey, buffalo, horse, bullock).
• They provide raw materials.
• They create employment opportunities and provide farm income.
• They provide recreation and serve as pets.
• They provide opportunities for agricultural research.
Animals provide foods such as milk, meat and eggs. Table 10.2 lists the major
classes and breeds producing these commodities.
Commodity
Milk
Figure 10.6 The Buffalypso breed.
Meat
Eggs
Animal class
• Cows
• Goats
• Cattle (beef)
• Pigs (pork, bacon)
• Sheep (lamb,
mutton)
• Poultry (chicken)
• Rabbits
• Poultry
Breed
• Jamaica Hope, Jersey, Holstein
• Toggenburg
• Jamaica Black, Zebu, Charolais, Buffalypso
• Landrace and Large White for pork; Tamworth for
bacon
• All breeds in the Caribbean are primarily raised for
meat, especially the Barbados Black Belly
• Vantress Cross, Peterson, Shaver
• New Zealand White, Flemish Giant
• White Leghorn, Rhode Island Red, Hyline; these
breeds can also be used for meat after their egg
production ceases
Figure 10.7 Rhode Island red chicken.
Table 10.2 The sources of milk, meat and eggs.
ITQ 3
Supply of raw materials
Describe the major roles of animals
on a farm.
Farm animals provide raw materials.
• All classes of animal produce dung /
droppings, which can be used as manure.
• Animal skins can provide leather and pelts for
manufacturing into garments and furniture.
• Sheep are not kept in the Caribbean for their
wool as the climate does not suit the wool
breeds but goats produce hair for carpets and
cloth, in addition to their skins for leather.
• The dung of pigs and cattle can be used to
generate biogas.
ITQ 4
State a breed of pig selected mainly
for bacon.
ITQ 5
Explain how raw materials from
animals, aside from food products,
are obtained and used.
152
Figure 10.8 Landrace piglet.
10: Introduction to animal sciences
Pets
Practical activity:
Collect pictures of different breeds
of farm animals. Write notes about
their characteristics and suitability
for the roles they fulfil on the farm.
Many types of animals are kept as pets and for recreational purposes. Rabbits,
goats and sheep may be kept as pets, whereas horses are bred for racing and
riding. Other pets are cats and dogs. These animals also protect farm animals from
predators and vermin.
10.3 Species of fish and bees
Common species of fish used for farming in the Caribbean
Aquaculture refers to the cultivation of aquatic plants and animals in specially
designed areas. There are three main types of aquatic environment.
Farming type
Freshwater
ITQ 6
Explain what aquaculture is and
state the THREE types of aquatic
environment.
ITQ 7
Give an example of a freshwater fish
that is farmed in the Caribbean.
ITQ 8
Explain why bees are farmed in the
Caribbean and why farmers need a
different variety of pollinators.
Brackish water
Salt or seawater (marine)
Species
Tilapia, shrimp, cascadura, black conches,
ornamental fish
Prawn, oyster, tilapia
Shrimp, lobster, turtle
Table 10.3 Aquatic environments and common species of aquatic animals used for farming.
Common species of bee used for farming in the Caribbean
Bees are farmed for honey, wax and crop pollination. The most common honey
bee species in the world is the western honey bee (Apis mellifera), which is also
known as the European honey bee (EHB). This species was domesticated for honey
production and crop pollination 9 000 years ago. Some crops are not pollinated by
honey bees, so a variety of pollinators are required for effective farming. Carpenter
bees (Xylocopa mordax) pollinate avocado, eggplant, pumpkin, pigeon pea, lemon,
watermelon and tomato crops. Only a few bee species pollinate pepper plants, for
example the long-horned bees (Melissodes trifasciata). There are several varieties of
the European honey bee but they are not easily distinguishable from one another.
These bees are common in the Caribbean. Africanised honey bees (AHBs) are a
cross between EHBs and African bees, originating from Tanzania. They are much
more defensive than EHBs, though some strains are ‘gentle’. AHBs will chase a
person for 400 m and attack in swarms to defend their hives, but they produce
more honey than EHBs.
Fish farming, Trinidad
At the Sugar Cane Feeds Centre in Trinidad, male
tilapia are preferred as these grow more quickly than
females do. The males have been created by ‘super male
technology’ (a system of genetic modification). The males
have only YY chromosomes, so they are known as super
males. The breeding cages contain five females and one
super male. The net holes of the cage are small enough
for the offspring to pass through into the breeding
ponds. When the fish are much larger, they are placed
into bigger growing ponds.
Figure 10.9
Breeding ponds, Trinidad.
153
Section C: Animal production
Revision map
Sheep
Cross-breeding is
popular in the Caribbean
as this gets the best
characteristics from
animals, e.g. Barbados Black
Belly sheep are heat tolerant,
and have coarse hair,
not wool
Cattle
Pigs
Poultry
The Sugar Feeds
Centre in Trinidad is
researching whether
domesticating wild native
breeds could help the
Caribbean islands
achieve food
security
Goats
Several classes
of farm animals
are reared in
the Caribbean
Rabbits
Jamaica
Black
Jamaica
Red
Breeds of
farm animals
Breeds were
introduced to the
Caribbean from other
parts of the world;
bred for quality meat
or adaptability
to the climate
Breeds of
farm animals
developed in the
Caribbean
Buffalypso
Barbados
Black Belly
Introduction to
animal sciences
Uses of
different breeds
of farm animals
Food
Jamaica
Hope
Species of
fish and bees
Bees are bred
to pollinate crops
and produce
honey
Power
The roles of
animals on
the farm
Recreation
Raw
materials
Aquaculture
is the breeding of
fish for food
Raw
materials
Manure for
fertiliser and
biogas
Leather
Pets
Skins
154
Goat hair
for carpets
Aquatic
environments
in the Caribbean
Freshwater
Salt water
(marine)
Brackish
water
10: Introduction to animal sciences
Examination-style questions
Multiple-choice questions
Write down the number of the question followed by the letter of the correct answer.
1.
2.
3.
Tamworth is the name of a breed of:
A dairy cattle
B goat
C pig
D poultry.
Which of the following is a breed of dairy cattle?
A Jamaica Hope
B Jamaica Red
C Jamaica Black
D Charolais
Which of the following is a freshwater farmed fish?
A Lobster
B Turtle
C Oyster
D Cascadura
Short-answer and essay-type questions
4.
5.
(a)
(b)
(a)
(b)
List FIVE classes of farm animal that are currently reared locally and regionally.
Name TWO breeds of any three classes of farm animal that you have listed for (a).
What classes of farm animal have been developed in the Caribbean region?
Complete the table, listing breeds of farm animal and the Caribbean country in which
they have been developed.
Breed of farm animal
6.
7.
8.
Caribbean country where developed
Give THREE reasons why people keep animals.
Explain why different breeds of bee have evolved. Give Caribbean examples in
your answer.
Describe the concept of ‘super male technology’ and explain why it is popular in
fish farming.
155
Section C: Animal production
11
Structure,
anatomy and
physiology
By the end of this unit you should be able to:
✔ compare the structures and functions of the digestive systems of nonruminants and ruminants
✔ describe the process of digestion in non-ruminant and ruminant animals
✔ compare digestions of ruminant and pseudo-ruminant animals.
Concept map
Structures and functions
of digestive systems
Non-ruminants
Nutrition
Poultry
Stages of digestion
Ruminants
Functions of digestive
system parts
156
Structure, anatomy and physiology
Process of digestion
Digestion in non-ruminants
Processes involved in digestion
Digestion in ruminants
Digestion in pseudo-ruminants
(rabbits)
Animal nutrient
requirements
Carbohydrates
Proteins
Fats
Minerals
Vitamins
Water
11: Structure, anatomy and physiology
11.1 The structures and functions of the
digestive systems of non-ruminants
and ruminants
Nutrition
Farm animals can only derive value from their food following ingestion, digestion
and absorption of nutrients into the bloodstream. The nutrients are assimilated
(taken into) into the body of the animal and either used or stored.
Nutrition is essential for:
• maintaining a supply of energy
• growth
• body maintenance and repair
• reproduction.
Non-ruminants – poultry example
Figure 11.1 Free-range chickens.
Poultry is one type of non-ruminant and pigs are another type of non-ruminant.
Figure 11.2 shows the digestive system of a bird and Figure 11.5 shows the
digestive system of a pig. In poultry, the crop and proventriculus form part of the
oesophagus. The gizzard is a tough, muscular organ that contains grit or small
stones. Powerful muscles in the gizzard contract and relax, helping to grind food.
In birds, the mouth is not used to grind food because there are no teeth present.
The digestive juices and their enzymes are similar in nature and function to those
secreted by a pig.
gall bladder
beak
oesophagus
ITQ 1
What is the name of the part of
the digestive system of a bird from
which the faeces are egested?
proventriculus
gizzard
crop
liver
small
intestine
(ileum)
large intestine (colon)
cloaca
rectum
caeca
Figure 11.2 The digestive system of a bird (chicken).
Structure
Beak
Mouth
Oesophagus (gullet)
Crop
Proventriculus
Gizzard
Liver
Ileum
Caecum
Rectum
Cloaca
Functions
Covers the jaws; picks up food and takes it into the mouth; can break up food mechanically.
Takes in food and swallows it using the tongue; no chewing as no teeth present.
Carries food to the crop.
Moistens food with digestive juice containing the enzyme salivary amylase; stores ingested food
temporarily.
Glandular part of the stomach, which secretes enzymes; also stores food.
Muscular part of the stomach; contains small stones that help to grind food.
Secretes bile, which is involved with the digestion of fats.
Produces some digestive enzymes; absorbs the products of digestion.
Usually two caeca; some digestion here of limited amounts of cellulose, through microbial activity.
Absorbs water from the faeces; stores faeces before egestion.
Common opening of the digestive, reproductive and urinary systems.
Table 11.1 Functions of the parts of the digestive system of a bird.
157
Section C: Animal production
Ruminants
ruminants ▶
Figure 11.3 A cow chewing the cud.
ITQ 2
Describe the process of chewing
the cud.
Ruminants are animals that eat grass and other vegetation and chew the cud
(ruminate), for example, sheep, goats and cattle. The cud is undigested vegetation
that has been swallowed and then regurgitated back into the mouth for thorough
chewing. When it is re-swallowed, the cud passes into the digestive system.
The stomach in ruminants is complex. At the base of the oesophagus there are four
compartments. Three of these, the rumen, reticulum and omasum, are referred
to as fore-stomachs. The fourth, the abomasum, is the true stomach. Ruminants
crop the vegetation, which is roughly chewed, mixed with saliva and swallowed.
It passes down the oesophagus into the rumen where it is stored. In the rumen,
bacteria and protozoa digest the cellulose in fibrous food. When the animal has
finished feeding, small quantities of food (each called a bolus) are regurgitated
back to the mouth for further chewing.
rumen
(1)
reticulum
(2)
omasum
(3)
small
caecum
intestine
rectum
(faeces
stored)
mouth
(food
taken in)
anus
(faeces
removed)
Practical activity:
If possible, visit an abattoir or
watch a video showing the different
parts of the digestive systems of
farm animals.
oesophagus
(passage to
rumen)
large
intestine
(food is chewed, swallowed
and regurgitated to be
chewed again)
abomasum:
true stomach
Bacteria and other micro-organisms in (1) and (2) break down cellulose.
Water is absorbed from (3). Digestion continues in the true stomach and small intestine.
Figure 11.4 The digestive system of the cow (a ruminant).
Functions of the digestive system parts
The ruminant digestive system differs from the non-ruminant system in the
complexity of the fore-stomachs and the stomach. Figure 11.5 shows the digestive
system of the pig and tables 11.2 and 11.3 summarise the functions of the digestive
systems of a pig (non-ruminant) and a cow (ruminant).
stomach (food stored,
proteins digested)
large intestine
(absorption of water)
anus
(faeces
removed)
mouth
(food
taken in)
oesophagus
(passage to stomach)
rectum
(faeces stored)
small intestine
(digestion and absorption)
Figure 11.5 The digestive system of the pig (a non-ruminant).
158
11: Structure, anatomy and physiology
Practical activity:
Examine parts of the digestive systems
of ruminants and non-ruminants. Create
a table like the one shown here to record
your observations. An example has been
completed for you.
Digestive
structure
Example:
Mouth
Ruminant
(cow)
Nonruminant
(pig)
Large flat teeth Incisors
at bottom of
(pointy) and
mouth
canine teeth
for tearing
Hard pad
instead of upper food
Short tongue,
teeth
contained in
Long,
mouth
sandpapery
tongue that
seems too big
for mouth
Structure
Mouth
Oesophagus
Stomach
Duodenum, pancreas
and liver
Ileum
Caecum
Colon
Rectum
Anus
Table 11.2 Functions of the parts of the digestive system of the pig (non-ruminant).
Structure
Mouth
Oesophagus
Rumen
Reticulum
Omasum
Abomasum
ITQ 3
State the function of the duodenum.
ITQ 4
Name the TWO functions of the
ileum in both the ruminant and the
non-ruminant digestive system.
Functions
Ingests and masticates (chews) food.
Transports food from mouth to stomach.
Stores ingested food; begins digestion of food; protein digestion.
Adds bile and pancreatic juice to food; breaks down
carbohydrates, fats and proteins.
Breaks down carbohydrates, fats and proteins further; absorbs
nutrients.
Microbial digestion of some cellulose in fibrous food takes place.
Microbial digestion of some cellulose takes place; absorbs water.
Stores undigested remains (faeces); absorbs water from the
faeces.
Egests (eliminates) the faeces.
Duodenum
Ileum
Colon
Rectum
Anus
Functions
Ingests and masticates food; chews the cud.
Transports food from the mouth to the rumen; brings regurgitated
food (boluses) from the rumen back into the mouth for rumination.
Stores ingested food; adds saliva to food; enzymes secreted by
bacteria and protozoa digest cellulose.
Separates larger pieces of food for regurgitation to the mouth via
the oesophagus.
Stores liquefied food; muscular contractions grind food into
finer particles; water and finer food particles moved into the
abomasum.
Stores liquefied food; enzymes carry out chemical digestion of
food (proteins).
Adds bile and pancreatic juice; similar to the pig.
Similar to the pig.
Absorbs water from the undigested material; transport of this
material to the rectum.
Stores undigested material (faeces).
Egests the faeces.
Table 11.3 Functions of the parts of the digestive system of the cow (ruminant).
11.2 The process of digestion
Non-ruminants (pigs)
non-ruminants ▶
Figure 11.6 A piglet.
digestive systems ▶
Non-ruminants, such as pigs, rabbits and poultry, have simple, or monogastric,
stomachs. There is no digestion of cellulose or highly fibrous foods in the upper
part of the digestive system. Some digestion of cellulose and highly fibrous foods
occurs in the large intestine and caecum through the activities of bacteria. Some
fibrous food material is needed in the diets of non-ruminant farm animals to
encourage peristalsis (the movement of food through the gut) and to prevent
constipation.
Stages of digestion
The digestive systems of farm animals vary in structure, but basically they all
consist of a tube called the digestive tract or alimentary canal, extending from
mouth to anus.
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Section C: Animal production
ingestion ▶
digestion ▶
absorption ▶
egestion ▶
All types of digestive systems carry out similar functions, which are:
• ingestion: intake of food
• digestion: breakdown of food
• absorption: uptake of nutrients into the bloodstream
• egestion: elimination of undigested residues (faeces).
Processes involved in digestion
Digestion is the process by which ingested food is broken down into simpler
compounds by the digestive system. These compounds are then absorbed through
the mucous membrane lining of the alimentary canal into the bloodstream.
physical processes ▶
chemical processes ▶
ITQ 5
microbial processes ▶
State the functions of a nonruminant digestive system.
The breakdown of food in digestion can involve physical, chemical and microbial
processes.
• Physical processes: Mastication (chewing) by the teeth breaks up the food.
Muscular contractions of the digestive tract (peristalsis) move food through
the alimentary canal to the stomach.
• Chemical processes: Enzymes in the digestive juices secreted along the
alimentary canal and by its associated organs break down food. Complex food
molecules are broken down into simpler, soluble substances.
• Microbial processes: Micro-organisms in the colon and caecum of nonruminants secrete enzymes that break down limited amounts of cellulose.
Parts of the alimentary canal
The main parts of the alimentary canal, or digestive system, are:
• the mouth
• the oesophagus, or gullet (including the crop in poultry)
• the stomach: simple (monogastric, e.g. pig); in birds the stomach is made up
of the proventriculus and the gizzard
• the small intestine: duodenum and ileum
• the large intestine: caecum, colon, rectum and anus
• the accessory, or associated, organ: salivary glands, liver and pancreas.
Food is chewed in the mouth and mixed with saliva, which contains water, mucus
and the enzyme salivary amylase. The water and mucus moisten food, making
it easier to swallow. The salivary amylase begins the process of breaking down
starch to sugars.
Figure 11.7 A Duroc sow and piglets in a
farrowing pen.
oesophagus ▶
peristalsis ▶
duodenum ▶
The stomach
Food is swallowed and enters the oesophagus (gullet). From here it is transported
into the stomach by a series of wave-like muscular contractions known as
peristalsis. Once in the stomach, the food is mixed with gastric juice and churned
by muscular contractions. The gastric juice, secreted by glands in the wall of the
stomach, contains mucus, hydrochloric acid and the enzyme pepsin, which starts
to break down the proteins into amino acids.
The small intestine
The food, now called chyme, enters the first part of the small intestine (the
duodenum). Here it is mixed with bile from the gall bladder and pancreatic
juice from the pancreas. Bile does not contain any enzymes but it emulsifies
(breaks down) large globules of fats into smaller droplets. This makes it easier
for the enzyme lipase (from the pancreatic juice) to digest the fats. Pancreatic
juice is alkaline and neutralises the very acidic chyme, creating the optimum pH
conditions (pH 7 to 8) for the action of enzymes in the small intestine.
Pancreatic juice contains the following enzymes:
• pancreatic amylase, which continues to break down starch into sugars
• lipase, which breaks down fats into fatty acids and glycerol
• trypsin, which continues to break down proteins into amino acids.
160
11: Structure, anatomy and physiology
ileum ▶
Food passes into the second part of the small intestine, the ileum. Intestinal juice
acts upon the chyme, continuing the digestion of the carbohydrates, fats and
proteins. The carbohydrates are broken down into simple sugars, the proteins into
amino acids and the fats into fatty acids and glycerol. The food is now in a fluid,
watery state referred to as chyle.
villi ▶
The wall of the ileum has many finger-like projections called villi (singular:
villus), which increase the surface area available for the absorption of the digested
food. Each villus has a thin wall and a dense network of capillaries. Sugars, amino
acids, fatty acids, glycerol, vitamins and minerals pass into the capillaries. From
here they are transported to the liver for processing and absorption into the body
cells.
colon ▶
The large intestine
After absorption has taken place, the food residues (water, undigested material,
cellulose, digestive secretions and bacteria) move into the colon, which makes
up a large part of the large intestine. Bacterial action in the caecum and the
colon results in the creation of some vitamins (vitamin B) and some digestion of
cellulose.
Much water is reabsorbed into the bloodstream from the colon. This reduces
water loss from the body. The residues, now called faeces, pass into the rectum,
where more water is reabsorbed. The faeces are stored in the rectum until they
are egested through the anus.
Digestion in ruminants
In the adult ruminant, food is taken into the mouth and roughly chewed, mixed
with saliva and swallowed. It moves by peristalsis down the oesophagus and into
the rumen. Saliva lubricates the food, making it easier to swallow and helping to
neutralise acids formed in the rumen by microbial activity. The saliva maintains
the pH of the rumen at the optimum level (pH 5.5 to 6.5). In the rumen, food
is continually churned by the rhythmic contractions of its walls. Ruminants
(including cattle and deer) are unable to digest plant material directly because
they lack enzymes to break down the cellulose in the cell walls.
Digestion in ruminants occurs as food passes through the four-chambered
stomach. Plant material is initially taken into the rumen, where it is processed
mechanically and exposed to bacteria that can break down cellulose (foregut
fermentation).
Through anti-peristaltic action, larger pieces of food form boluses. The boluses are
regurgitated one by one back up the oesophagus into the mouth. Here, each bolus
is chewed 40 to 50 times before it is swallowed again. The chewing breaks up the
food physically and provides a larger surface area for the action of enzymes from
micro-organisms (bacteria and protozoa).
On re-entering the rumen, food is exposed to enzymes produced by microorganisms. This brings about chemical digestion. The contractions of the rumen
and reticulum help to separate large particles of food for regurgitation to the
mouth. Finer particles are channelled to the omasum, where they are stored
temporarily.
The omasum crushes the food particles, squeezing water and liquid food into
the abomasum or true stomach. In the abomasum, gastric juice, including the
digestive enzyme lysozyme, which breaks down the bacteria to release nutrients,
is secreted. The course of digestion from this point on is similar to that in nonruminants.
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Section C: Animal production
In suckling ruminants, such as calves, kids and lambs, the rumen and reticulum
are not yet fully developed. They enlarge only when the young animals begin to
consume solid food. The milk they take in is channelled directly to the omasum
and abomasum for digestion.
Digestion in pseudo-ruminants (rabbits)
pseudo-ruminant ▶
The rabbit is a herbivore with a simple stomach and not a ruminant. The rabbit
is a pseudo-ruminant, which means that it does not chew the cud or have a
rumen, but it does depend on the bacterial digestion of cellulose for much of its
nutrition.
Rabbits are fed on:
• herbage: water grass, kudzu, sweet potato vines, railway daisy, rabbit meat
(herb), leaves of lettuce, cabbage, cauliflower, bodi beans and pak-choi
• root crops: carrot, sweet potato, radish and cassava
• concentrates: rabbit ration or substitutes such as broiler starter, chick starter,
pullet grower and pig grower
• kitchen scraps: bread soaked in milk, discarded leaves of cabbage, pak-choi,
lettuce and cauliflower, vegetable peelings.
ITQ 6
Explain why fresh herbage is allowed
to wilt before it is fed to a rabbit.
caecum ▶
appendix ▶
coprophagy ▶
Fresh herbage is collected, cleaned and spread thinly on a herbage rack to wilt
before feeding. Wilting reduces the moisture content and helps to prevent soft,
watery faeces or ‘scouring’.
The rabbit’s diet contains cellulose, which is not broken down until the food
reaches the caecum. Undigested food passes from the small intestine into the
caecum and appendix where there are cellulose-digesting bacteria that break
down cellulose into organic acids. Faecal pellets (droppings) egested during the
night are produced by the caecum and are soft. These pellets are eaten by the
rabbit, supplying vitamins and amino acids as well as the products of the bacterial
digestion of cellulose. Hard, dry faecal pellets are produced during the daytime
and consist of undigested food wastes. The alimentary canal has a very large
caecum in which microbial action takes place.
The habit of eating the soft droppings is called coprophagy and enables the
animal to derive the greatest amount of nutrition from the ingested and reingested material.
ITQ 7
ileum
Describe the process of coprophagy.
stomach
ITQ 8
caecum containing
bacteria to digest
cellulose
Explain how coprophagy benefits the
rabbit.
oesophagus
Practical activity:
Examine a dissected rabbit and
identify the different parts of the
digestive system. Take a photograph
and label it using a computer.
colon
rectum
duodenum
1. Food is eaten for the first time
anus
night faeces
second faeces
(solid droppings)
2. Night faeces are eaten
Figure 11.8 The digestive system of a rabbit (a pseudo-ruminant).
162
11: Structure, anatomy and physiology
Revision map
Can involve
physical processes
that break up the food
and move it along the
alimentary canal
Ileum
Rectum
Digestion
Ingestion
Absorption
Anus
Stomach
Hard dry
pellets during
the day
Egestion
Soft pellets
at night that
are ingested
(coprophagy)
Does
not chew
the cud
Mouth
Processes
carried out
Duodenum
Colon
Oesophagus
Growth
Main parts
of the digestive
system
Occurs in
the digestive
systems of some
animals
Reproduction
Nutrition,
which
provides
energy
Pseudoruminant
Has
cellulose-digesting
bacteria in its
caecum
Herbivore
with a simple
stomach
Repair and
maintenance
of tissues
Apart
from differences in
the stomachs, digestive
processes are similar in
both ruminants and
non-ruminants
The rabbit
Microbial
breakdown
of cellulose
Products
of this can
be absorbed
Produces two
types of faecal
pellets
Structures
and functions
of digestive
systems
Digestion is
the process in which
ingested food is broken
downto simpler, soluble
substances that
can be absorbed
Chemical
digestion is brought
about by the action
of enzymes
Process of
digestion
Non-ruminants
Generally little
digestion of
cellulose
May be
some cellulosedigesting
bacteria
Structure,
anatomy and
physiology
In the
caecum and
colon
Beak
Mouth
Non-ruminant
digestive
systems
Crop
Digestive
system of
a bird
Proventriculus
Products
of this may be
absorbed
The rest of the
alimentary canal is
similar in structure and
function to that of
a non-ruminant
Ruminant
digestive
systems
Rumen
mechanical
digestion in a bird
is achieved by the beak
and small stones in
the gizzard
(no teeth)
Gizzard
Benefits
from the bacterial
breakdown of
cellulose
Four
compartments
at the base of the
oesophagus
Reticulum
Omasum
Duodenum
Caecum
Rectum
Cloaca
Ileum
Ruminant
animals
Colon
Ruminant
processes
Cellulosedigesting
bacteria and
protozoa
Sheep
Cattle
Abomasum
(true
stomach)
Goats
Chew
the cud
Eat
vegetation
163
Section C: Animal production
Examination-style questions
Multiple-choice questions
Write down the number of the question followed by the letter of the correct answer.
1.
2.
3.
4.
Digestion is:
A the intake of food
B the breakdown of food
C the absorption of food
D the elimination of faeces.
The muscular part of the stomach of a bird is called:
A the oesophagus
B the crop
C the proventriculus
D the gizzard.
The true stomach of a ruminant is called:
A the abomasum
B the omasum
C the reticulum
D the rumen.
The digestion of fats occurs in:
A the stomach and the duodenum
B the duodenum and the ileum
C the stomach and the ileum
D the ileum and the caecum.
Short-answer and essay-type questions
5.
6.
7.
8.
(a)
(b)
(c)
(a)
(b)
(c)
(d)
What is the meaning of digestion?
Describe THREE major activities by which food is digested or broken down.
Of what importance is digestion to farm animals?
Define what is meant by a ‘digestive system’.
State the functions carried out by digestive systems.
List the main parts of the digestive system.
Explain why a limited amount of cellulose digestion takes place in the digestive tract
of non-ruminants.
(a) What are the functions of the following parts of the pig’s digestive system?
(i) Stomach
(ii) Ileum
(b) Describe food digestion in the duodenum of the pig.
(a) Complete the table, stating the functions of parts of a chicken’s digestive system.
Parts
Proventriculus
Crop
Caecum
9.
164
(b)
(a)
(b)
(c)
Functions
Describe the process of food digestion in the gizzard of poultry.
Explain the meaning of ‘cud’ as it relates to ruminants.
State the functions of the various parts of the ruminant’s stomach.
Describe the process of food digestion in the stomach of an adult ruminant.
Section C: Animal production
12
Nutrition and
management
By the end of this unit you should be able to:
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
explain a ‘complete ration’
select appropriate rations for each stage of growth of broilers and layers
calculate the feed conversion ratio (FCR) and explain its importance
describe systems of grazing
state the advantages and disadvantages of different grazing systems
explain the importance of forages (grasses and legumes) in livestock
feeding
explain the measures used to feed ruminants when forage is unavailable
describe the management practices associated with the care of baby chicks
and baby rabbits (kittens)
explain the management practices associated with rearing broilers, layers
and rabbits
rear a batch of 50 broilers per term
describe the general signs of illness in farm animals
identify the cause, clinical signs, prevention and control of pests and
diseases of poultry and rabbits
identify the cause, clinical signs, prevention and control of internal
parasites of livestock.
Concept map
Animals rations
The complete ration
Types
Broilers
Layers
Feed conversion ratio (FCR)
Importance
Local materials for feeds
Feeding ruminants when
forage is unavailable
Hay making
Silage making
Nutrition and management
Systems of grazing
Zero grazing
Rotational grazing
Strip grazing
Continuous grazing
Pasture management
Tips
Advantages and
disadvantages
Care of young chicks and rabbits
Brooding
Poultry
Rabbits
Management
Rearing
Animal health
Pests and
diseases
Poultry
Rabbits
Livestock
Symptoms
Prevention
Control
Importance of forages
Feedstuffs
Grasses
Legumes
Non-legumes
165
Section C: Animal production
12.1 The ‘complete ration’
ration ▶
Figure 12.1 Layers need a certain type
of ration.
In farming, the term ration refers to the type, quality and quantity of food that is
fed to a particular farm animal or group of animals. A ration can be divided into:
• the maintenance part is for body repairs and metabolic processes. It supplies
the animal’s energy and protein needs with no gain or loss in weight
• the production part supplies the extra food needed to produce meat, eggs,
milk or wool.
For rations, the following factors need to be considered:
• the age of the animals
• their physical condition
• the stage of growth they have reached
• the essential food nutrients they need.
Ideally, a ration should supply all the essential food substances in their correct
proportions.
Types of rations
maintenance ration ▶
There are three types of rations: maintenance, production and complete. The
maintenance ration is a diet that satisfies the energy (carbohydrates and fats)
and protein needs of the animal. It provides the animal with the nutrition it needs
to carry out body repairs (maintenance) and metabolic processes, without any
gain or loss in its stored energy reserves or body weight.
production ration ▶
The production ration is the extra food, added to the maintenance requirement,
which is used by the farm animal for productive purposes. Farm animals need the
production ration to produce milk, eggs, hair or wool, as well to develop offspring
(calves, lambs, kids) and build body mass.
complete ration ▶
A complete ration consists of all the essential nutrients, in amounts needed to
satisfy both the maintenance and the production requirements of the animal.
ITQ 1
What is the difference between a
maintenance ration and a production
ration?
A complete ration:
• supplies all the essential food constituents
• has the correct proportion of energy to protein, as well as vitamins and
minerals
• is usually tastier and satisfies the animal’s appetite.
A lack of any essential food constituent may damage the health and productivity
of an animal. But overfeeding can also be a problem. Feeding an animal too much
food wastes the farmer’s money. Nutrients will just be lost in the faeces and health
problems may develop in the farm animal.
12.2 Rations for broilers and layers
Practical activities:
1. Examine labels from
commercial rations and identify
the nutrient components.
2. Visit a local feed mill.
166
When choosing rations for poultry you need to consider:
• the stage of growth or development: chicks, adult broilers, pullets or
laying hens
• the name of the ration: starter, grower, finisher and laying or egg ration
• the cost: high-protein feeds, such as starter, are usually more expensive than
low-protein feeds, such as finisher; high-protein feed is used to form new
body tissues and strong bones.
12: Nutrition and management
starter ration ▶
grower ration ▶
laying ration ▶
Poultry are fed starter ration from day-old chicks until they are six weeks old.
Hens reared for egg production are then fed on grower ration until they are
15 weeks old. At 15 weeks, they are fed on laying ration, or egg ration, until
they are culled.
Poultry that is reared for production (broilers) are fed on finisher ration from
7–9 weeks old.
12.3 Feed conversion ratio (FCR)
feed conversion ratio (FCR) ▶
ITQ 2
Define the feed conversion ratio.
ITQ 3
Suggest why a young animal has
a more efficient FCR than an older
one does.
All farm animals, especially those reared for meat (broilers, piglets and calves)
convert feed consumed into body mass. The feed conversion ratio (FCR) is the
number of units of feed, measured in kilograms, that the animal needs to produce
a one-unit increase in its body weight, also measured in kilograms. It is expressed,
for example, as 3.0 : 1 or 2.5 : 1, that is 3 kg of feed or 2.5 kg of feed is needed to
produce a 1 kg increase in body weight.
This ratio links the efficiency of the farm animal with the cost of feed to the
farmer. The efficiency of conversion can vary among animals of the same breed
and in the same litter. In a group of calves, some may have an FCR of 3.5 : 1 and
others an FCR of 3.0 : 1. The calves with the lower FCR are more efficient at
converting food into body mass than those with the higher FCR.
A young animal converts feed more efficiently than an older one does. For
example, a piglet may have an FCR of 1.5 : 1, but as it grows and increases in size,
the FCR increases. This is shown in Table 12.1.
Live weight (kg)
15
45
60
90
Practical activities:
1. If possible, rear some chicks as
broilers or layers, feeding them
the appropriate ration for their
age and stage of development.
Pay particular attention to the
composition of the feedstuffs
given at each stage.
2. Keep records of the chicks that
are raised, noting the feed
given, the finished weight of
the broilers and records of egg
production by the layers.
Feed conversion ratio (FCR)
1.5 : 1
2.5 : 1
3.0 : 1
3.5 : 1
Table 12.1 Variation of FCR with size in a pig.
Different classes of livestock have different FCRs, as shown in Table 12.2.
Class of livestock
Cattle
Pig
Goat
Rabbit
Chicken
Average feed conversion ratio (FCR)
4.5 to 5.0 : 1
3.5 to 4.0 : 1
4.5 to 5.0 : 1
3.0 to 3.5 : 1
3.0 to 3.5 : 1
Table 12.2 FCR of different classes of livestock.
Worked example: Calculating FCR
How much feed would need to be supplied to a group of 12 pigs, with an average weight of 60 kg, in order for
them to increase their average weight to 70 kg?
Feed conversion ratio for a 60 kg pig is 3.0 : 1.
So for each additional kg in weight increase, each pig needs 3 kg of feed.
For a 10 kg increase, 30 kg of feed is required.
The total for the group of 12 pigs is (12 × 30) = 360 kg.
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Section C: Animal production
12.4 The importance of FCR
Feed is a major expense when rearing livestock, especially meat-producing
animals. An understanding of FCR can be helpful in:
• selecting classes and breeds of animals that have a low FCR
• identifying particular animals that are efficient feed converters; these animals
can be kept for replacement stock and breeding purposes
• raising early-maturing farm animals, thereby controlling expenditure on feed
• marketing batches of mature farm animals promptly before the FCR increases;
this prevents spending more on feed at a time when the increase in body
weight is slowing down.
Local materials for livestock feeds
Feed for farm animals can be sourced locally. Several crop plants, for example,
cereals, grasses and legumes, are specifically grown for animal feed. Crops that
do not reach marketable quality, for example, poor-quality sweet potatoes, yams,
carrots and cassava, and the trimmings from leafy crops such as cabbages are also
used to feed livestock. By-products from food processing are also good sources of
animal feedstuffs.
Practical activity:
Examine samples of different
feedstuffs and evaluate their
nutritional benefits to farm
livestock. In groups, create posters
for a classroom display.
The following local materials are useful.
• Bagasse and molasses from the processing of sugar cane can be used for
cattle feed.
• Fishmeal from fish is a high-protein supplement used in aquaculture.
• Rice bran, rice husks and rice-middling, in the form of a bran mash, is used
for rabbits and horses.
• Wheat-middling, wheat bran, oat bran and soybean meal from the milling
and processing of cereals is used for rabbits and horses. Soybean meal is used
as a protein supplement for dairy cows.
• Citrus pulp and citrus meal provides a concentrated source of nutrients for
dairy and beef cattle and sheep. It is rich in calcium.
• Coconut meal is used as a protein supplement for livestock.
• Cocoa pod meal from the processing of cocoa beans is used in livestock and
poultry feed.
• Brewer’s grain and hops from the brewing industry are a good source of
proteins and water-soluble vitamins. These materials are useful for both
ruminants and non-ruminants.
• Urea from fertiliser manufacturing is mixed with bagasse and is used to feed
beef cattle.
• Waste food (swill) from restaurants and hotels is used to feed pigs.
12.5 Systems of grazing
Grazing animals eat grasses or the leaves of other plants. Examples of grazing
animals are cattle, goats and sheep.
Grazing systems focus on:
• the effective use of pasture grass or legumes (the sward)
• maintenance of high-quality forage for a long period
• the balanced regrowth of grass and legumes after grazing
• a high level of production from ruminant livestock.
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12: Nutrition and management
forages ▶
Forages are green pasture grasses, legumes, mulberry and neem. The forages
are cut and fed to the animals in stalls or the farm animals are allowed to graze.
Forages also include the thick, fleshy, juicy stems, roots, fruits and leaves of certain
crops, such as sweet potato, cassava and banana.
Zero grazing (soilage or soiling)
zero grazing ▶
Zero grazing refers to the cutting, chopping and feeding of forage crops to
ruminants housed in pens or stalls. The animals feed on grass without having to
graze, hence the term zero grazing.
Examples of the soilage grass or legume mixtures used in this system include:
• elephant grass or Centrosema
• Guinea grass or kudzu
• Guatemala grass or Stylosanthes
• pangola grass or Centrosema.
Rotational grazing
rotational grazing ▶
In rotational grazing, the pasture area is subdivided into six or eight paddocks.
Each is systematically grazed in sequence, with the ruminants being moved from
one paddock to another. The stocking rate is usually high, 20 –25 cows per hectare.
Each paddock is grazed for three to seven days, depending on the stocking rate
and herbage growth. After that time, the paddock is rested and the animals are
moved to another paddock. The system continues until the last paddock has been
grazed and the cycle is then repeated. When paddocks are not being grazed they
undergo pasture management.
ruminants graze paddocks in rotation
paddock 1
(grazed for
3-7 days)
paddock 2
paddock 3
paddock 4
paddock 5
paddock 6
ruminants are moved from one paddock to another in sequence
Figure 12.2 Rotational grazing.
Strip grazing
strip grazing ▶
Strip grazing is a variation of the rotational system. A single paddock is grazed
progressively, strip by strip, using movable electric fences to restrict the animals.
The fences can be moved forwards once or twice daily, offering the animals a strip
of fresh pasture for grazing.
forward movement
fixed fence
restricted area
or strip for
grazing
ruminants
electric fences moved
forward once or twice daily
fixed fence
Figure 12.3 The strip grazing system.
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Section C: Animal production
Continuous grazing
continuous grazing ▶
In continuous grazing, animals are allowed to graze on the same pasture area
for a very long period. This system is normally practised on expansive range
lands only, where fencing is absent and probably impractical. The stocking rate is
usually low.
Deferred grazing
deferred grazing ▶
In deferred grazing, certain paddocks of pasture grass or legumes are withheld
for later use. In tropical countries, it is the practice of conserving ‘standing hay’.
The forage that is withheld usually matures, loses its succulence, palatability and
some nutritive value, but it is important as a maintenance ration, especially in the
dry season. Leafier grasses and legumes, such as Guinea grass or kudzu and giant
star grass or Centrosema are most suitable for this type of grazing.
ITQ 4
Pasture management
Name THREE types of grazing
systems.
Farmers who rear ruminants recognise the importance of establishing good
pastures and managing them effectively. A well-managed pasture will:
• provide palatable (tasty), digestible and nutritious food for ruminants
• guarantee a continuous supply of fresh food
• promote forage conservation for periods of slow growth, drought and scarcity
• reduce expenditure on commercial feeds.
ITQ 5
Explain why it is important to carry
out pasture management.
Management tips
On well-established pasture, the farmer can maintain the pasture by carrying out
the activities listed here.
• Adopt systems of grazing to achieve the most efficient use of the forage
produced.
• Avoid overgrazing or close grazing because this slows the regrowth and root
development of grasses and legumes. The death of forage plants could result
in bare patches and soil erosion.
• Avoid under-grazing. Under-grazing leads to a decrease in the nutritive value
of the pasture because the protein content decreases and the fibre content
increases. This promotes patches of tall, dense grass.
• Tine-harrow the pasture after rotational grazing and after rain. This breaks up
matted stolons, spreads around dung from the grazing animals and prevents
the growth of unsuitable grasses.
• Mow or brushcut pasture after rotational grazing. This removes the coarse
growth, promotes tillering of the grasses and controls weeds.
• Apply fertilisers at regular intervals. This supplies nutrients for plant growth
and promotes the rapid regrowth of forage.
• Clear clogged drains and watercourses.
• Mend pasture fences.
• Prune or replant shade trees.
Practical activities:
Visit farms with ruminant animals. Observe the farms’ grazing systems and how the pasture is managed. In groups, write a summary
describing how efficient each farm is. Farm efficiency in this case is how quickly the animals are fattened on each farm. Try to answer
these questions in your group.
1. Are the grazing systems efficient?
2. How could the pasture be managed differently to improve efficiency?
170
12: Nutrition and management
The advantages and disadvantages of different grazing
systems
System
Zero grazing
Advantages
• Makes efficient use of the forage.
• There is a high level of animal
production.
• Herbage is not trampled or fouled
by the animals.
• Forage can be harvested at its
most succulent, palatable and
nutritious stage.
Rotational grazing
• Overcomes the problems
associated with overgrazing and
under-grazing.
• It makes efficient use of the
forage.
• It promotes a high level of
production.
• Animals with high nutritional
needs, such as dairy cows (high
producers), can be given ‘first bite’
of the luxuriant pasture and this is
then followed by low producers,
such as dry cows or sheep.
• Overcomes the problems
associated with overgrazing and
under-grazing.
• It makes efficient use of the
forage.
• It promotes a high level of
production.
• The pasture is uniformly grazed.
• There is less trampling and fouling
with dung.
• Efficiency of forage use can be
increased by 15 – 20% on highquality pastures.
• In the rainy season, there is an
abundance of forage.
• Pasture is normally under-grazed
because the stocking rate is
relatively low.
ITQ 6
State TWO advantages and TWO
disadvantages of zero grazing.
Strip grazing
Continuous grazing
ITQ 7
Explain why the pasture area is
under-grazed during the rainy season
in a continuous grazing system.
Deferred grazing
• Provides a maintenance ration for
animals during the dry season.
This system can be used by
ruminant farmers in the tropics.
Disadvantages
• Special machinery and equipment
for harvesting, transporting and
chopping is needed.
• There are high costs related to
setting up and maintaining housing
for the animals, the machinery and
the equipment.
• There is an increase in labour
costs, bedding material for the
animals and manure disposal.
• The numbers of animals reared is
restricted: it is suitable only for
small herds of ruminants.
• It requires a relatively large area
of pasture land, e.g. 10 or more
hectares.
• It may suffer from a lack of water
during dry weather conditions.
• Most suitable for high-quality
pastures as animals will have a
restricted intake if pasture is poor.
• In the dry season, overgrazing can
occur and the sward (grassy area
or pasture) takes a longer time to
recover and regrow so animals
may need to be supplied with an
additional sub-maintenance ration.
• There can be a build-up of ticks
and intestinal parasitic worms on
the pasture.
• It provides only a maintenance
ration and taller grasses may
smother the growth of legumes,
creating an imbalance in the
grass / legume sward.
Table 12.3 Advantages and disadvantages of different grazing systems.
171
Section C: Animal production
12.6 The importance of forages in livestock
feeding
Feedstuffs
feedstuffs ▶
fodder ▶
silage ▶
concentrates ▶
ITQ 8
Name THREE different types of
feedstuffs.
Livestock feeds, known as feedstuffs, provide nutrients for energy, growth,
development, maintenance, production and reproduction.
Feedstuffs can be classified into the following groups.
• Fodder: Dried feedstuffs, such as hay, straw and chaff, are used when forage
is unavailable. Fodder can also include green chopped feedstuffs, for example,
corn stalks, elephant grass and kudzu.
• Silage: Silage is pasture grasses, legumes and other crops that have been
conserved and stored in silos.
• Concentrates: Concentrates are produced commercially in feed mills using
local and imported foodstuffs. They are designed to suit the maintenance
and production needs of different farm animals and they can be mixed,
mashed, ground, granular or pelleted. Concentrates may be high protein, low
protein, high fibre, low fibre, high carbohydrate, rich in essential vitamins and
minerals, or have a low percentage of fat or low moisture content.
The nutritive value of feedstuffs varies. Laboratory analysis provides information
on the total amounts, in percentages, of the crude (potential) nutrients contained
in commercial feeds. These are expressed as total digestive nutrients (TDN) or net
energy values (NEV). Farm animals, however, can only use the nutrients from
foods that have been digested. This means that some nutrients are always lost in
the undigested material that passes out in the faeces.
In selecting forage plants (grasses and legumes), farmers need to consider the
following factors.
• Productivity: High-yielding varieties that grow quickly and respond favourably
to nitrogen fertilisers are desirable.
• Palatability: Farm animals will eat more if the grasses are tasty.
• Nutritive value: Some plants are more easily digested than others and some
plants are particularly high in protein or minerals.
• Adaptability: Plants need to be able to adapt to soil and weather conditions.
The wet season brings high rainfall and the dry season brings drought, so
plants must be drought-resistant.
The nutritional value of forages is directly related to the stage of growth. As forage
plants age and grow to maturity, the crude fibre content increases and the protein
content decreases. It is usual to apply nitrogen fertilisers to pasture grasses to
increase the protein content. Most green herbage is rich in carotene (which plays
a role in the formation of vitamin A) and also in vitamin E and the B vitamins.
Grasses
Grasses used as herbage for farm animals can be divided into two groups: pasture
and soiling. Table 12.4 compares these two groups.
Pasture grasses
Cultivated and managed as a crop.
Farm animals are allowed to graze the sward.
Suitable for rotational and continuous grazing.
Examples: pangola, para.
Soiling grasses
Cultivated and managed as a crop.
Usually farm animals are not allowed to graze.
Normally cut and fed to farm animals (zero grazing).
Examples: elephant, Guatemala, Guinea.
Table 12.4 A comparison of herbage grasses.
172
12: Nutrition and management
Pangola grass (Digitaria decumbens)
Pangola grass is a native plant of South Africa. It is a perennial with long stolons,
rooting to form a turf. It grows best in well-drained moist areas, but it can
withstand continuous close grazing, flooding and drought. It responds favourably
to nitrogen fertiliser and can be propagated by stem cuttings or root divisions
(setts).
Figure 12.4 Para grass.
Para grass (Brachiaria mutica)
Para grass is a native plant of tropical Africa and of South America, including
Trinidad. It is a creeping perennial with stolons and produces stems that grow
to 2 m or more. It is suitable for moist, lowland pastures and provides excellent,
palatable fodder if eaten when the plants are young. It does not stand up well to
heavy or continuous grazing, but it grows well in combination with Centrosema.
Elephant grass, Napier grass or king grass (Pennisetum purpureum)
Elephant grass or Napier grass (sometimes called king grass), is indigenous to
Nigeria and has spread throughout tropical Africa. Giant King Grass is a nongenetically modified, perennial grass suitable for tropical and subtropical regions.
This grass is also a low-carbon, renewable replacement for coal and oil in the
generation of electricity and heat in anaerobic biodigesters. It is also useful for
green biochemicals, bioplastics and biomaterials. Giant King Grass is also palatable
and has a high nutritive value when it is young. It is a high-protein feed for
livestock that is not too fibrous when it is cut every 40 – 60 days at 150 – 200 cm
tall. It is drought-resistant but cannot survive heavy or continuous grazing. It is
an excellent grass for silage-making and soilage. It grows well with Centrosema and
can be established from stem cuttings.
Figure 12.5 Elephant grass.
Guinea grass (Panicum maximum)
Guinea grass, a native of Africa, is found throughout the humid tropics and subtropics. It has similar properties to elephant grass, but grows only 2–3 m high. It
can survive drought but dies if it is heavily grazed. It is excellent for zero grazing
and combines well with Centrosema and Stylosanthes. It can be established by seeds
or root divisions.
Guatemala grass (Tripsacum laxum)
This perennial grass grows tall and leafy, forming large clumps. It is droughtresistant but it is easily uprooted by grazing animals. It is a good grass for silagemaking and soiling, although it has a lower nutritive value than elephant grass.
African star grass (Cynodon plectostachyus)
This is found throughout the tropics and sub-tropics, growing well in warm,
humid climates. It is a perennial with creeping stems that grow rapidly, providing
quick coverage of bare ground and forming a turf 120 cm high. It will grow on a
range of fertile soils and tolerates close grazing. It does not create viable seeds so
it has to be established from cuttings.
Figure 12.6 Guatemala grass.
Antelope grass (Echinochloa pyramidalis)
Antelope grass is a native plant of southern Africa and is a reed-like perennial
that grows 300 cm high. It grows in swamps but is drought-tolerant. It makes
useful hay and silage and excellent dry-season grazing. The young growth is very
palatable. In some parts of Africa, people eat the grain.
Tanner grass (Brachiaria arrecta)
Tanner grass is a native of southern Africa and has been naturalised in the tropics
and sub-tropics. It is similar to para grass and it will hybridise with it. It can be
propagated from stem cuttings and is easily established to give complete ground
cover. In contrast to para grass, it can survive heavy grazing.
173
Section C: Animal production
Legumes
Pasture legumes are either herbaceous plants, such as kudzu or Centrosema, or
shrubs, such as Leucaena or Gliricidia. They are very important forage plants
because they:
• fix or add nitrogen to the soil
• help to maintain the fertility of tropical pastures
• promote the growth of the pasture grasses
• increase the palatability, digestibility and nutritional value of the forage grass
and legume combination.
Figure 12.7 Centrosema.
Figure 12.8 Gliricidia.
Legumes are superior to grasses in protein and mineral content. Their nutritional
value does not decline as much with age or maturity as it does with grasses. The
straws of the legumes are richer in protein, calcium and magnesium than cereal
straws and other grass crops.
However, large amounts of legumes in the forage mixture can cause scouring
(smelly, watery faeces) and bloat (an excessive amount of gas in the digestive tract
of the farm animal). For this reason, the legume content of the forage mixture is
kept around or below 50%. Also, young, succulent herbage (grass and legume) is
wilted before being fed to livestock.
Some legumes cultivated in combination with grasses, locally and regionally, are
described next.
ITQ 9
Explain why farmers should use
forages before the plants are
fully mature.
Practical activities:
1. Establish small grass and
legume plots in your school
grounds, using different
combinations of grasses and
legumes.
2. Make a collection of grasses
and other forage plants.
Identify them and mount them
on sheets of card for reference.
174
Stylosanthes
There are several species of Stylosanthes used as forage plants. Stylo Caribbean
(Stylosanthes hamata) is a short-lived perennial legume that can grow in hot dry
conditions. It will grow on well-drained soils and tolerates heavy grazing. It can
be planted with sown grasses, but it is generally oversown into native pasture
after the pasture has been treated with fertiliser. Stylosanthes guianensis is suited to
poor soils in high-rainfall areas. It has a high nutritional value if it is eaten before
it flowers. It combines well with Guinea and para grasses and can be established
by seeds.
Desmodium (Sweethearts)
This is found throughout the tropics and is widely used as a forage legume. It is a
trailing vine and well adapted to moist, tropical soils. It is grown in combination
with Savanna, Bermuda and pangola grasses. It can be propagated by seeds.
Centro or Centrosema (Centrosema pubescens)
Centro is a leafy perennial that trails along the ground. It can be established from
seed and may be combined with Bermuda, Guinea, elephant and para grasses.
12: Nutrition and management
Leucaena research at Sugar Cane
Research Feed Centre, Trinidad
Leucaena, also known as wild tamarind, is a useful forage as it contains 24% protein.
However, the high levels of protein have resulted in the plant generating secondary
metabolites called memozine, which are toxic to rabbits and poultry. It is not possible
to feed large quantities to small mammals. Memozine also causes illnesses in goats
and sheep, although the Feed Centre has inoculated the adult ruminants so
their immunity has been passed to offspring. The goat herds and sheep
flocks at the centre can eat Leucaena without a problem. The Feed
Centre has tried to remove memozine directly from the plant,
but this stunts growth.
Figure 12.9
Leucaena, Trinidad.
Kudzu (Pueraria phaseoloides)
This legume is very similar to centro and combines well with many different
grasses.
Leucaena (Leucaena leucocephala)
This is a perennial shrubby legume, which is deep-rooted and drought-tolerant.
It grows in well-drained soils in warm regions and needs at least 600 mm of
annual rainfall. It can be interplanted with elephant grass. It provides the highest
quality feed of any tropical legume and has the potential to produce the highest
weight gains when fed to cattle. Its deep roots allow it to produce new leaves after
shallow-rooted grasses have run out of moisture.
Gliricidia (Gliricidia sepium)
Gliricidia is an evergreen shrub cultivated for green fodder. It can be interplanted
with elephant grass and is a source of protein.
Non-legumes
Other herbs, shrubs and trees, such as mulberry and neem, may be used as forage
for ruminants.
Figure 12.10 Young mulberry plant.
Mulberry (Morus genus)
Mulberry leaves are highly palatable and digestible to herbivorous animals. The
leaves and young stems can be harvested and fed to ruminants. The protein
content is high and this type of forage has been used to replace some concentrates
in the diets of farm animals.
Neem (Azadirachta indica)
Neem is a member of the mahogany family and a native of the Indian subcontinent. It has been established in the Caribbean for over a century. It grows
best where annual rainfall is 400 –1 200 mm. It is best known for its medicinal
and pesticide properties. It has bitter foliage but is browsed by goats and camels.
Its foliage can be used as an emergency livestock feed.
Trichanthera
The leaves of Trichanthera (Trichanthera gigantea) can be eaten by pigs.
Figure 12.11 Trichanthera.
175
Section C: Animal production
12.7 Feeding ruminants when forage is
unavailable
Pastures can produce good-quality forage for ruminant livestock. However, on
most farms the pasture is rain-fed, producing high yields of palatable, nutritious
forage during the rainy season and lower yields of poorer quality during the dry
season. Caribbean farmers have adopted strategies to overcome this problem of
forage conservation, so that their livestock have nutritious forage all year round.
There are three major forage conservation techniques:
• hay making
• silage making
• deferred grazing (see Section 12.5).
Hay making
Hay making has two requirements: young grass with an abundance of leafy
materials and weather conditions that are sunny and windy.
ITQ 10
List the steps involved in hay making.
The hay-making process involves these steps.
• The grass is cut before the flowering stage when its nutritive value, palatability
and yield are high.
• Sunshine and wind are used to dry the grass quickly. The cut grass is spread
out in rows on the open field and turned at regular intervals for quick and
uniform drying. This process continues until the moisture content has been
reduced from 80% to 15–20%.
• When the moisture content is right, the hay is collected in small bundles and
stacked. It is then stored in a cool dry area of the barn until it is needed to feed
ruminant livestock. The stored hay should be unblemished, unbleached and
have a pleasant aroma.
Silage making
silage ▶
ensiling ▶
silo ▶
ITQ 11
Describe what happens during the
fermentation stage of silage making.
176
Silage consists of green forage crops that have been cut and preserved in a
succulent, palatable and nutritious condition for later use as feeding material for
ruminant livestock. The nutritive value depends on the growth stage at which the
grass was cut and the quality of the silage depends on the fermentation process
within the silo. The process of silage making is called ensiling or ensilage, and the
container in which it is made is called a silo.
Ensilage involves the following stages.
• Cutting the grass or forage crop: This is done at the young, leafy, immature
stage and the plant material wilted in the sun to reduce its moisture content.
• Filling the silo: The cut material is spread out uniformly in layers in the silo.
• Compressing the material: A four-wheeled tractor or heavy roller is used to
compress the material. This controls respiration within the material in the silo.
Inadequate compaction results in excessive respiration and overheating. It
also creates conditions favourable for bacteria to produce butyric acid, which
makes the silage foul-smelling and unpalatable. Over-compaction of the silage
can also create conditions in which butyric acid is formed by bacteria.
• Fermenting: Aerobic bacteria convert carbohydrates into acetic acid and
lactic acid.
• Controlling temperature: Temperature within the silo needs to be kept around
32–38 °C. Inadequate compaction causes overheating.
• Regulating pH: Acidity needs to be at pH 4.2 or lower to suppress the
production of butyric acid.
12: Nutrition and management
In addition to feeding ruminants hay and silage, farmers can supplement animals’
diets with commercially prepared concentrates to compensate for the lack of fresh
forage.
12.8 The care of young chicks and rabbits
In nature, female animals usually take care of their young until they are old
enough to look after themselves. However, in livestock farming, farmers take care
of the young animals using recommended farming practices. The farmers do this
to increase production and make greater profits.
Some management practices are common to all farm animals, for example,
housing, feeding, cleaning and preventing disease. Other practices are specific to
the young of particular animals.
Figure 12.12 Natural brooding.
brooding ▶
Brooding in poultry
Brooding involves taking care of day-old chicks for 2–3 weeks. It takes place in
an enclosed area where the chicks are housed, protected, fed and kept warm.
There are two forms of brooding:
• natural brooding requiring a broody hen
• artificial brooding requiring a brooder.
natural brooding ▶
artificial brooding ▶
litter
feed
container
lamp
water
container
cardboard
surround
Figure 12.13 A brooder and brooding
equipment.
Natural brooding
In natural brooding, the hen incubates a clutch of eggs and produces a brood
of chicks. She provides protection and warmth for the newly hatched chicks. She
keeps them under her wings and feathered body until they develop feathers and
are able to withstand colder weather conditions. If the area around the poultry
house is securely fenced, the hen may roam freely with her chicks. Alternatively,
she may be confined to a coop, which protects her and the chicks from rain, hot
sun, draughts and predators such as rats, mongooses and stray cats. The farmer
ensures that both the hen and the chicks have sufficient feed and water at all
times.
Artificial brooding
In artificial brooding, the day-old chicks are housed in a specially prepared
area, usually a corner of the poultry house, where they are protected, kept warm
and provided with litter, feed and water.
These steps should be taken before using a brooder.
• Clean and disinfect the entire poultry pen 2–3 days before the chicks arrive.
• The area needed for the brooder needs to be the right size. Calculate the area
size by allowing 225 cm2 per chick (15 cm × 15 cm).
• Separate the area from the rest of the poultry pen using a movable partition.
• Screen the outer walls with feed bags or cardboard to keep out cold draughts
of air.
• Put litter (bagasse, wood shavings or straw) on the concrete floor in a layer
5–7 cm thick. The litter absorbs droppings and keeps the chicks off the cold
ground.
• Set up lighting and heating over the centre of the brooding area. Use an infrared bulb or a 150-watt light bulb together with a concave reflector to direct
heat and light down to the floor. Heat keeps the chicks warm and the light
encourages them to feed, so the chicks will gain weight quickly.
• Spread sheets of newspaper over the litter for the introduction of feed to the
chicks on Day 1 and Day 2 of brooding.
177
Section C: Animal production
• Put two mini-waterers and two mini-feeders (trays) at opposite ends of the
brooder within the lighted area.
• Place a clipboard with a record sheet attached at the entrance for poultry
record-keeping.
• Place a footbath containing disinfectant at the entrance. Everyone entering
the poultry pen should disinfect their footwear to prevent infection with
disease-causing organisms.
The brooding process begins when the chicks are placed in the brooder and ends
when they have enough feathers to cope with the weather conditions. During
this time, the chicks are checked on a regular basis.
ITQ 12
Describe the type of feed used for
the chicks.
Management practice
Cleanliness
Health
Feed
Water
Temperature
After brooding, they may be placed in other poultry pens or the movable partitions
can be shifted to give the chicks access to more space (about 900 cm2 per chick)
in the poultry house. Table 12.5 summarises the management practices for raising
chicks.
Procedure
• Step into the footbath to clean footwear.
• Regularly replace newspaper soiled with droppings during the first two days.
• Clean and refill feeders and waterers twice daily.
• Stir litter twice a week to incorporate droppings, adding more litter if necessary.
• Count and check chicks for injury and abnormality.
• If they have not been inoculated (immunised), give them protection.
• To protect against Marek’s disease, inject Marex into the back of the neck.
• To protect against Newcastle disease / infectious bronchitis combined, place one drop of vaccine in one eye only.
• To protect against fowl pox, insert vaccine by piercing the web of the wing at 2 – 3 weeks of age (especially for layers).
• Place broiler starter feed into the mini-feeders.
• Scatter feed onto the newspapers spread on the litter when the chicks are first placed in brooder.
• Add antibiotics and vitamins to the drinking water to combat stress and for healthy growth.
• Add a sulphur drug, such as 5-sulfas, to prevent intestinal bleeding due to coccidiosis (caused by coccidia, which are
pathogenic protozoa).
• Keep the initial temperature at 35 °C; then reduce it by 2 °C each week until it reaches 24 – 26 °C.
• Adjust the temperature by raising or lowering the lamp.
• Check the chicks to see whether they are too hot (chicks staying outside the lighted area), too cold (chicks huddled under
the light) or just right (chicks spread out under the lighted area).
Table 12.5 Management practices for the care of chicks.
debeaking ▶
Chicks that will become layers are debeaked to prevent them causing damage to
other members of the flock. In debeaking, a third of the top beak of each bird
is removed with a hot iron (a debeaker). This part is burned off and the beak is
cauterised.
ITQ 13
Explain how the temperature at
which chicks are brooded needs to
be controlled.
kittens ▶
178
Brooding in rabbits
In rabbits, the act of giving birth is called kindling. A nest box containing dried
grass is placed in the hutch of the pregnant doe and she lines it with fur pulled
from her own body. The doe is allowed to give birth peacefully and suckle her
young. The young rabbits, called kittens, are born naked (hairless) with their
eyes closed (blind). The litter size may vary from 3–10 kittens. Table 12.6 describes
the management practices required for the care of young rabbits.
12: Nutrition and management
Management practice
Cleanliness
Feed
Water
Procedure
• Remove and dispose of any dead kittens.
• Wash feeders and waterers daily.
• Incorporate droppings in deep litter beneath the hutch of the doe.
It is not necessary to provide feed and water for very young rabbits as
they suckle until they are six weeks old. Provide the doe with wilted
herbage, concentrates and water every day so that she can make milk
for the young rabbits.
Supply clean water regularly.
Table 12.6 Management practices for the care of young rabbits.
The kittens leave the nest box after three weeks and begin nibbling solid food
(herbage and starter ration) 2–3 weeks later. Weaning takes place at 6–8 weeks
when the doe is removed to another hutch.
12.9 Management practices associated with
rearing broilers, layers and rabbits
There are good reasons for the management practices used in rearing livestock. The
provision of suitable housing protects animals from predators and unfavourable
weather. By rearing the young in enclosed areas, they can be provided with
the conditions that promote growth. In the artificial incubation of chicks, light
conditions encourage feeding and the temperature is adjusted to the stage of
growth. The rate of growth is reduced if the temperature is too low. Large numbers
of healthy chicks can be produced for the poultry industry.
Rearing rabbits
Keeping the housing and equipment clean helps reduce the risk of infection and
prevent disease. Droppings are removed and feeding equipment is kept clean.
Feed and water left too long can become contaminated and this might cause
infections that spread quickly. It is not necessary to provide feed and water for
very young rabbits as they suckle until they are six weeks old, but the does need
clean food and water every day for making milk to feed the young.
ITQ 14
Describe the food that should be
provided for the young rabbits when
they are six weeks old.
Adult rabbits are fed on wilted herbage and concentrates. They are excellent
converters of feed and can reach 1.8 kg in eight weeks, with a feed conversion ratio
(FCR) of 3.5 : 1. The young rabbits are provided with herbage and concentrates
just before and after weaning.
Rearing poultry
grower ration ▶
laying ration ▶
finisher ration ▶
cannibalism ▶
The provision of suitable feed at different stages of growth ensures that the young
gain weight rapidly. Young chicks are fed on starter ration until they are six weeks
old. If they are being reared for egg production, this is changed to grower ration
until they are 15 weeks old. Laying ration, or egg ration, is fed to them for the
rest of their productive lives. Broilers are given finisher ration from seven weeks
until they are culled at nine weeks. These rations are designed for maximum
productivity.
Cannibalism occurs amongst chickens. Members of a flock peck each other,
causing bleeding and loss of flesh. If severe, it may result in death. To avoid this
problem, chicks are debeaked. The problem can be reduced by hanging small
bundles of fresh herbage (grass) in the pens of laying birds. This practice has the
added advantage that the hens produce eggs with orange-coloured yolks.
179
Section C: Animal production
Practical activity:
Start a small class rabbitry and a
batch of broilers and layers. If this is
not possible, visit farms at different
times of the year where chicks and
rabbits are being reared, to observe
and record the practices used. Make
notes on these visits for future
reference.
There may be a poultry pen
available already, but you must
clean and disinfect it and any
equipment before use. Keep careful
records of all costs: the cost of feed,
heating and lighting, the chicks,
any medication needed and the
transport costs to obtain the chicks
or market the broilers.
ITQ 15
What is the normal rectal
temperature of sheep and goats?
12.10 Rearing a batch of broilers
You need to consider the following aspects when you rear broilers.
• The location of the housing for the poultry
• The size of the housing, based on the numbers of chicks to be reared
as broilers
• The house’s construction: materials needed and their source; provision of
water, heating and lighting
• The equipment required: feeders; waterers; cleaning equipment
• The feed: type needed; quantity required; storage facilities for the feed
• The chick: source of day-old chicks
• The immunisation required, if it has not been carried out already
• The record-keeping
• The maintenance: organisation of checking, feeding and cleaning
• The marketing needed: broilers at nine weeks
• The costs: a balance sheet of the inputs and the income
12.11 Animal health
In livestock farming, high-quality products from healthy animals are marketed
for profit. Farmers must take care therefore that their livestock are kept as healthy
as possible. A farmer should recognise the characteristics of good health and the
signs of ill-health in the stock. In addition, the farmer should give first aid to
animals as soon as injuries and illnesses have been detected.
Healthy animal
• Alert and responsive to environmental stimuli.
• Eyes are bright with no mucus on the sides or
eyelids.
• Coat is smooth, with a sheen. The skin is soft
and pliable (flexible).
• Appetite is good and the ration is eaten
eagerly.
• Produces relatively firm faeces without
straining.
• Bleats, grunts or moos normally and does not
sound distressed.
• Does not limp when walking.
• Mixes with the flock or herd and is not
isolated.
• Has a normal rectal temperature for its class:
poultry 41 °C, goats and sheep 39.4 °C, pigs
39.2 °C, cattle 38.6 °C.
Unhealthy animal
• Lacks alertness and fails to respond quickly to
environmental stimuli.
• Eyes are dull and watery with mucus on the
sides and the eyelids.
• Coat is dull and ruffled, with swellings or
lesions on the skin.
• Poor appetite and listless (low in energy).
• Urine discoloured: reddish or greenish.
• Constipated or scouring.
• Shivering or groaning with pain.
• Walks slowly, with discomfort or lies down
for long periods, lacking the energy to
stand up.
• General dullness and droopiness.
• Coughing, sneezing, noisy breathing sounds.
• Isolated from the flock or herd, being unable
to keep up when grazing or walking.
• High rectal temperature, indicating a fever.
In poultry, signs of ill-health include:
• loss of appetite
• respiratory problems.
Table 12.7 Characteristics of healthy and unhealthy animals.
180
12: Nutrition and management
12.12 Pests and diseases of poultry and rabbits:
symptoms, prevention and control
Poultry
The major poultry diseases are Newcastle disease, fowl pox, Marek’s disease,
coccidiosis and pullorum (see Table 12.8). There is also concern about bird flu.
Disease
Newcastle disease: caused by a virus; affects
poultry of all ages.
Symptoms
• Loss of appetite; droopiness; nasal mucus
discharge; twitching of head and neck;
breathing difficulties; paralysis and sudden
death.
• Mortality rate is high.
Fowl pox: caused by a virus.
• Small warts or blotches all over the body,
later developing into black scabs on the comb,
wattles and beak.
• Mortality rate is low to moderate.
Marek’s disease: caused by a herpes virus.
• Twisting of the neck and head (wry neck);
droopy wings; loss of weight; grey colour of
the iris; paralysis followed by death.
• Disease can take several forms.
• Mortality rate is high.
Coccidiosis: caused by a protozoan.
• Droopiness and loss of appetite; diarrhoea
with blood in faeces; vent (cloaca) becomes
swollen and bloody.
• Mortality rate is moderate.
Pullorum: caused by the bacterium Salmonella
pullorum; mostly affects young birds up to three
weeks old; associated with cannibalism.
• Loss of appetite; droopiness; white diarrhoea;
continual chirping.
• Mortality rate is high.
Bird flu (avian influenza): caused by a virus.
• Swelling of the head; blue colouration of the
comb and wattles; loss of appetite; breathing
problems; diarrhoea; drop in egg production;
sudden death.
Prevention and control
• There is no treatment for infected birds.
• Young chicks should be vaccinated.
• Adopt sanitary measures by using a footbath,
cleaning and disinfecting poultry pens, feeders
and waterers.
• Dead birds should be buried or burned.
• There is no treatment for infected birds.
• Young birds should be vaccinated.
• All infected birds should be isolated.
• Carcasses should be buried or burned.
• There is no treatment for infected birds.
• Day-old chicks should be vaccinated.
• Strict hygiene should be followed.
• Isolate infected birds and burn or bury
carcasses.
• Resistant strains of poultry are available.
• Treat with sulfa drugs and magnesium
sulphate in the drinking water.
• Birds should be removed from wet, infected
litter.
• Stocking density should be reduced.
• Coccidiostats can be added to feed
concentrates.
• Birds that recover have good immunity to the
same parasite.
• Can be treated with antibiotics.
• Isolate infected birds.
• Adopt sanitary measures, cleaning and
disinfecting poultry pens, using footbaths and
cleaning feeders and waterers.
• Litter should be stirred frequently to absorb
droppings.
• Bacterium is destroyed by normal
disinfectants.
• There is no cure, but good nutrition and
antibiotics may alleviate symptoms.
• Vaccination is not normally recommended as
vaccinated birds may remain carriers.
• Infected birds should be isolated.
• Sanitary methods should be adopted.
• If outbreak occurs, slaughter the birds and
burn the carcasses.
Table 12.8 Poultry diseases: their symptoms, prevention and control.
181
Section C: Animal production
Rabbits
The major diseases are snuffles, coccidiosis, mange, bloat and sore hocks. However,
only the first three diseases are of economic importance (see Table 12.9).
Disease
Snuffles:
caused by a bacterial infection.
Symptoms
• Nasal discharge of mucus; sneezing; rubbing
of nose and eyes with forepaws.
Coccidiosis:
caused by a protozoan.
• Loss of appetite; diarrhoea; droopiness; loss
of weight.
Mange:
caused by a parasitic mite.
• Head shaking, itching and scratching; thick
crusts of mites accumulating inside the ear;
loss of fur; sores in the ears.
Prevention and control
• Treat with sulfa drugs and antibiotics.
• Isolate infected rabbits.
• Feed a nutritious diet and adopt sanitary measures.
• Do not breed the infected animals; even if recovery
occurs, the animals may still be carriers.
• Isolate infected rabbits.
• Place in hutches, not on litter, to prevent
contamination from faeces.
• Adopt strict sanitary measures.
• Use sulfa drugs in the feed or added to drinking water.
• Massage mineral oil into the ear.
• Clean infected areas with antiseptic solution; apply
lime / sulphur ointment.
• Adopt strict sanitary measures; clean and disinfect the
rabbitry.
Table 12.9 Rabbit diseases: their symptoms, prevention and control.
Sore hocks usually occur in rabbits kept in cages with wire floors. The sores that
develop on the feet and foot pads affect the general condition of the rabbits but
cause few deaths. Affected animals should be moved to hutches with solid floors
and sores treated with antibiotic ointment.
The cause of bloat is not known, but rabbits show a loss of appetite, a drop in
weight and diarrhoea. Treatment with antibiotics seems to improve the condition.
12.13 Pests and diseases of livestock:
symptoms, prevention and control
ITQ 16
Explain why it is important to
isolate infected animals (through
quarantine) once symptoms of
disease are seen.
Pest / Disease
Blackleg: generally fatal bacterial
disease of young cattle or sheep of
any age.
182
Immunity is passed from mother to offspring in the mother’s antibody-rich
colostrum (first milk). However, because of the impact that internal parasites
have on livestock, vaccines have been developed to support an animal’s immune
system. The following pests and diseases are managed by routine vaccination.
Where vaccination has not been developed, antibiotics are used to manage the
severity of the infection.
Symptoms
• Lameness, depression, loss of appetite and a hot
painful swelling on a limb, which crackles when
pressed may indicate blackleg. Later, the skin over
the swelling will become cold, dry and leathery.
• The disease is seen as acute, localised inflammation
of muscle tissue due to growth of the blackleg
organism.
• This is followed by generalised toxaemia or
poisoning of the animal causing rapid death.
Prevention and control
• Burning the upper layer of soil to eradicate left-over
spores is the best way to stop the spread of blackleg
from diseased cattle.
• Diseased cattle should be isolated.
• Treatment is generally unrewarding due to the rapid
progression of the disease, but penicillin (antibiotics)
can be given to manage the infection.
12: Nutrition and management
Pest / Disease
Leptospirosis: spiral-shaped bacteria
that affects a range of livestock and
humans.
Symptoms
• Redwater in calves.
• Late abortion in pigs, stillbirth (born dead) or piglets
lack vitality.
• Many infected animals do not show signs of clinical
disease.
Orf: caused by parapox virus and
affects sheep and goats.
• Orf is a painful condition of sheep and goats that
causes scabby lesions around the nose, the inside
and outside of the mouth and on other parts of the
body including the feet. In the case of nursing ewes,
the teats can also be affected.
• Pain may cause unweaned lambs to die from
starvation or dehydration due to not suckling.
• Rapid infection that is usually fatal.
• Variety of infections depending on specific bacteria.
• Lamb dysentery, Struck (necrotic enteritis), pulpy
kidney, braxy (malignant oedema), black disease,
blackleg, tetanus.
Clostridial diseases: caused by large
spore-forming rod-shaped bacteria;
can affect any livestock, most
common in cattle and sheep.
Erysipelas: caused by a bacterium
and affects pigs.
Stillbirths, mummification, embryonic
death and infertility syndrome
(SMEDI): reproductive disease in pigs
caused by a virus.
African swine fever virus (ASFV):
large double-stranded DNA virus
that affects pigs.
• Diamonds is the classic acute form of the disease.
This is also a septicaemia form, although milder, in
which raised red diamond-shaped lesions appear
particularly over the back. The pig may have a
high temperature (42 °C+), be depressed and lack
appetite. Pigs so affected or those in contact can
develop chronic signs such as skin sloughing or may
be found dead 4 – 10 days later (possibly having
appeared to recover) as a result of endocarditis.
• There is an arthritic form, where rear legs stiffen
producing severe lameness.
• Pregnant sow suffers lesions of the area between
inner and outer uterus walls (myometrium).
• Foetus shows retarded growth, congestion of
superficial vessels, which may be associated with
haemorrhage and dehydration, resulting in the
mummification of the foetus.
• Signs typically occur 3 – 15 days after infection.
• Early signs are non-specific and include high fever,
lack of energy and loss of appetite. Pigs may die
suddenly without further disease signs.
• At later stages, further signs may be observed
including reddening of the skin (visible only in paleskinned pigs), with patches appearing on the tips of
ears, tail, feet, chest or under the belly, diarrhoea,
vomiting, laboured breathing, swollen red eyes, eye
discharge, abortions, stillbirths, increasing signs of
disease and unwillingness to get up.
• In severe cases, death can sometimes be the only
sign of infection.
Prevention and control
• Leptospirosis is spread by the urine of infected
animals.
• Avoiding letting milking yards drain directly into
paddocks can help.
• Vaccination is most effective: two shots 4 – 6 weeks
apart.
• Quarantine infected animals. Vaccinate lambs to
manage the virus within the flock.
• Condition is self-limiting and clears up in 3 – 4
weeks.
Can be managed through the following good farming
practices.
• Minimise trauma and treat wounds promptly.
• Control liver fluke infection.
• Keep areas such as calving / lambing pens clean,
use antibiotic cover after difficult births.
• Separate animals from infected carcasses and
dispose of carcasses promptly.
• The bacterium can survive in soil or dung for six
months or more.
• It can also be carried by a wide range of wild birds
as well as rodents, especially mice.
• The disease can be controlled by a combination of
hygiene, medication and vaccination.
• The disease is spread most often by eating food or
drinking water contaminated with infected faeces,
and occasionally through sexual contact and contact
with aborted tissue.
• Good farming practices can reduce the spread.
• Vaccination with porcine parvovirus can increase
immunity.
• The disease can be spread directly through contact.
It can also be spread indirectly through feeding
infected pig meat and /or pork products.
• It can also be spread by species of soft tick in some
regions and possibly by blood-sucking flies or insects
as well as through contaminated objects such as
vehicles, clothes and equipment.
• Currently no vaccine or treatment, so strict
biosecurity measures are only method of
management.
Table 12.10 Livestock diseases: their symptoms, prevention and control.
183
Section C: Animal production
Revision map
Maintaining
clean housing and
equipment will prevent
pests and disease
affecting the young
animals
Palatability
Adaptability
Nutritive
value
Young chicks
and rabbits need
specific care
to thrive
Disease and
parasites cause
animals to become
unwell
Illness in
farm animals
Pests and
diseases need to be
prevented and outbreaks
on a farm should be
controlled
Palatability
of the
forage
Although grass
is the cheapest food
for ruminants, factors
are considered in
establishing a
pasture
Management
of baby chicks
and rabbits
A healthy animal
shows symptoms of
wellness; an unhealthy
animal has symptoms
of disease
Add nitrogen
to the soil
Productivity
Pasture
legumes
Nutrition and
management
The nutritive
value of feedstuffs varies,
but can be determined by
laboratory analysis and
expressed as total
digestible nutrients (TDN)
or net energy
values (NEV)
Increase
the nutritive
value
A grass /
legume pasture is
more palatable and better
balanced nutritionally
than a grass
pasture only
Forages
Silage
Due to the
seasonality of
rainfall in the Caribbean,
farmers adopt forage
conservation strategies,
such as hay and silage
making
Feed
consumed is converted
into body mass. The feed
conversion ratio (FCR) is the
number of units of feed (kg)
required to produce an
increase of one unit (kg)
of body mass
Animal
rations
Grazing
systems are
designed to make
the best use of pasture
in the production
of ruminant
animals
Feedstuffs,
or foods for
livestock
Forages
Promote
the growth of
the pasture
grasses
Fodder
Feedstuffs can be
prepared from local
and imported
material
Ruminant
livestock farmers
usually manage pastures
on a sustained
basis
Appropriate
rations take into
account the
animal
Fertilising
Grazing
Replanting
Development
of the animal
Age
Stage
of growth
184
Controls
expenditure
on feed
Zero
grazing
Rotational
grazing
Continuous
grazing
Concentrates
Tine-harrowing
Helps
farmers to
select suitable
breeds of
animals
A maintenance
ration supplies the energy
and protein needs of the
animal without any
gain or loss in
its weight
The ration of a
farm animal should be
balanced, supplying all
essential food substances
in their correct
proportions
The production
ration is the extra food,
added to the maintenance
requirement, which is used
for productive
purposes
12: Nutrition and management
Examination-style questions
Multiple-choice questions
Write down the number of the question followed by the letter of the correct answer.
1.
2.
3.
Dried feedstuffs, such as chaff, hay and straw, are known as:
A forage
B fodder
C silage
The appropriate ration for broilers would be:
A starter
B grower
C finisher
As forage plants age:
A the fibre content increases and the protein content decreases
B the fibre content increases and the protein content increases
C the fibre content decreases and the protein content increases
D the fibre content decreases and the protein content decreases.
D concentrates.
D layer.
Short-answer and essay-type questions
4.
(a) Explain the meaning of: (i) forage and (ii) forage plants.
(b) Give examples of the following forages:
(i) ONE grass that is local to the Caribbean
(ii) THREE grasses that have been introduced into the Caribbean.
(c) State the main qualities that should be considered when selecting forages.
5. (a) Distinguish between (i) grasses and (ii) legumes (pasture).
(b) List, with TWO examples each, the main groups of:
(i) grasses
(ii) legumes (pasture).
6. (a)Using appropriate examples, differentiate between (i) pasture grasses and (ii) soiling grasses.
(b) Explain why farmers should cultivate grasses and legumes together in their pastures.
(c) Name and describe each of the following:
(i) a pasture grass
(ii) a soiling grass
(iii) a pasture legume.
7. (a) List FIVE pasture management techniques.
(b) Explain why farmers should:
(i) brushcut pastures after rotational grazing
(ii) tine-harrow pastures after rotational grazing and rain
(iii) spray pastures regularly.
8. (a) List the major types of grazing systems.
(b) Describe any TWO systems you have listed for (a), using the following subheadings:
(i) Name of grazing system (ii) Description
(iii) Advantages
9. (a) Differentiate between (i) rotational grazing and (ii) strip grazing.
(b) State the main advantages of strip grazing.
(c) What are the major disadvantages of rotational grazing?
10. (a) List the major forage conservation practices that Caribbean farmers can use.
(b) Describe the process and procedure of hay making.
(c) State the desirable qualities of hay.
11. (a) What is silage?
(b) List the types of silos used for making and storing silage.
(c) Describe the process of silage making.
12. Describe the process involved in raising a brood of chicks.
13. Describe the signs of a healthy animal.
14. Using TWO examples, explain how diseases in animals can be avoided.
(iv) Disadvantages
185
Section C: Animal production
13
Fish and bee
management
By the end of this unit you should be able to:
✔ explain the factors to be considered in the establishment and management
of a fish farm
✔ explain the factors to be considered in the siting and establishment of
✔
✔
✔
✔
✔
Concept map
an apiary
explain the economic importance of bees
differentiate among the types of bees in a hive
describe the social activities of bees
identify the causes, symptoms, prevention, control and cure of pest and
disease infestation in bees
describe the harvesting of honey and other bee products.
Fish and bee management
Apiculture
Aquaculture
Establishing and
managing a fish farm
Extensive systems
Intensive systems
Hatcheries
Setting up
Harvesting
Coastal agriculture
Mariculture
186
Bee-keeping
Apiary
Bee selection
Economic importance
Management of bees
Types of bees
Social activities
Pests and diseases
Products
Honey
Beeswax
Medicinal products
Propolis
Pollen
Royal jelly
13: Fish and bee management
aquaculture, apiculture ▶
Fish farming and bee-keeping are becoming more important in the Caribbean.
Fish farming is called aquaculture and bee-keeping is called apiculture (from
the Latin word for bee, apis). As with all types of farming, fish farming and beekeeping need special skills.
13.1 Factors in establishing and managing a
fish farm
Aquaculture is the cultivation of selected aquatic plants and animals in specially
designed areas, using appropriate management principles and techniques.
There are three main types of aquatic environment.
• Freshwater farming: This type of farming includes tilapia rearing, shrimp
farming, cascadura rearing, rearing black conches, cultivating water lilies and
ornamental fish farming.
• Brackish water farming: This type of farming includes prawn farming, oyster
farming and tilapia farming.
• Salt or seawater (marine) farming: This type of farming includes shrimp
farming, sea moss cultivation, lobster farming and turtle farming.
Aquaculture has an important role to play in developing the local economy
because it:
• increases fish production
• satisfies the nutritional needs of the population
• promotes employment in local communities
• generates additional income for farmers
• uses resources (people, land and water) more effectively
• means that fish and fish products do not have to be imported.
When establishing a freshwater aquaculture system, several factors should
be considered, for example, the types of fish to be farmed (such as tilapia or
cascadura), the production system and the type of pond.
Production systems may be intensive with high stocking rates (10 – 40 fish / m3),
semi-intensive with a moderate stocking rates (4–5 fish / m3) or extensive with
low stocking rates (1–2 fish / 20 m3).
Figure 13.1 Pond at a fish farm.
extensive systems ▶
Extensive systems
Extensive systems involve fish being taken from a local river and placed in
ponds. Animal manure is used as a fertiliser to promote the growth of pondweed,
which oxygenates the water and provides food for the fish. This system is cheap
as it does not require much labour or additional food for the fish.
Intensive systems
intensive systems ▶
Intensive systems involve tanks or ponds in which conditions are strictly
controlled. The temperature is kept within the optimum range for the type of
fish, and the oxygen levels and pH are carefully monitored to ensure maximum
growth rate. Care is taken to ensure that organic matter from farm sewage or
silage does not get into the water. Organic matter promotes the growth of bluegreen algae, which can be toxic to fish. Algal blooms can also block pipes and
waterways.
187
Section C: Animal production
stream
outlet channel
walkway
supply canal
Figure 13.2 The layout of ponds in an intensive fish farm
(an aerial plan).
Ponds may be concrete or earthen. The best earthen ponds are of a
clay soil type. Ponds built of other soil types need to be lined with
durable plastic and compacted to prevent leakage. Most ponds
will be 1.5–2 m deep, and the number and size of the ponds will
depend on the scale of the project and the production system.
Ponds must be capable of holding unpolluted water all year round.
They should be sited where there is some shade.
In a large fish farm, a series of ponds is constructed with walkways
between them so that there is access for cleaning and feeding. The
ponds are linked to common inlet and outlet channels for water
flow. The series of ponds allows for fish of different ages and stages
of growth to be reared so that there is a continuous supply for
market.
Hatcheries for fish breeding and fingerling management
Although most fish breed freely in ponds, it is important for farmers (producers)
to consider using properly produced fingerlings (young fish). Quality fingerlings
in aquaculture are vital, as poor fingerlings result in poor harvests. Farmers should
generate their own fingerlings if they do not know the quality of the fingerlings
available. This requires investment in hatcheries.
Developing a hatchery allows the farmer to have fingerlings ready and available
whenever they are needed. As long as the demand for fingerlings exists, a wellmanaged hatchery can become a profitable business.
Three methods of fingerling production are commonly practised in the Caribbean:
• open ponds
• tanks
• hapas (net enclosures) placed in ponds.
Fry (newly hatched fish) are collected from the spawning units and placed in
fertilised ponds for rearing to the fingerling stage. After that, they are placed in
growing ponds.
Hapa method of fingerling production
A hapa is a rectangular or square net cage placed in a pond for holding fish. They
are made of fine mesh netting material so the fry cannot escape. Hapa sizes vary
but the ideal size measures 3 m long, 3 m wide, and 1.5 m deep.
Figure 13.3 Red hybrid in a hapa net.
188
When using hapas to generate fingerlings:
• stock brooders used should be at a ratio of about 1 : 5 to 1 : 7 males to females
with 4 brooders / m² (for tilapia)
• hapas should be inspected for fry every day
• the fry should be removed using a scoop net after two weeks and stocked in
tanks, other hapas or a rearing pond
• fry reared in a hapa should be fed four times per day until the fry reach the
desired size (5 g for tilapia)
• a diet in powder form should be used at the rate of 5–10% of the total body
weight of all the fish per day.
13: Fish and bee management
Practical activity:
If possible, visit an aquaculture
project and find out how much
fish farming is carried out locally
and regionally. If there is no fish
farming in your area, search the
internet to find out whether there
are any proposed governmentfunded projects to encourage the
development of aquaculture.
Advantages of the hapa method
• Fry and brooders are easily handled.
• Production per unit of area is high.
• Uniform fry of relatively similar age
is assured.
• The loss of fry is minimised.
• Hapas can be set up in ponds
stocked with fish.
Disadvantages of the hapa method
• Management is more demanding compared with open
ponds.
• Fish may die because of aggressiveness during
spawning.
• Feeding is necessary.
• Hapas can be destroyed during stormy weather.
• Hapa material will degrade in sunlight and need
replacing.
• Fish may easily escape if the hapa is damaged.
• Localised poor water quality may result from uneaten
feed and fish waste.
• Hapa mesh will get clogged, limiting water circulation
and needing periodic scrubbing.
Table 13.1 Advantages and disadvantages of the hapa method.
Figure 13.4 An intensive fish farm: note
the nets over the ponds.
ITQ 1
Name TWO types of fish that can be
farmed in fresh water.
ITQ 2
State which conditions are controlled
in intensive fish farming systems.
Setting up
When setting up a fish farm, these management practices need to be considered.
• Protection: Fences and bird nets can be used to protect fish against predators
such as alligators and birds.
• Aeration: The demand for oxygen increases with the number of fish in
the pond, so intensive systems with high stocking rates will need to have
equipment to aerate (oxygenate) water in the pond.
• Fertilising: Fertilisers can be added to water to encourage the growth of algae,
which is a source of food for the fish.
• Sampling: Growth of fish can be monitored weekly by weighing a sample of
approximately 2.5% of the population in the pond.
• Observing: Observations of water quality, health of fish, behaviour and
mortality should be made daily.
• Record-keeping: Records should be kept of all observations, sampling weights,
feeding and aeration on a regular basis.
Harvesting
Harvesting takes place when fish have reached their ideal market weight
(0.5 – 0.75 kg for tilapia). The time taken to reach this weight depends on the age
of the fingerlings, the feed quality and the feeding regime. Generally, two-monthold fingerlings raised in ponds can be harvested in four months.
ITQ 3
Explain how fish farmers can protect
their ponds from predators.
Sugar Cane Feeds Centre, Trinidad
There are government aquaculture project sites, such as the Sugar Cane Feeds Centre, from
which young fish, called fingerlings, can be obtained. Farmers with established aquaculture
enterprises where fish are allowed to breed may also be a source of fingerlings.
The choice of feeds and the method of feeding will depend on the fish species and the production system
chosen. Feed millers, such as National Flour Mills, or feed depots can supply sinking or floating fish feed in the
form of pellets or feeds for other animals (broiler starter or pullet grower). Tilapia can eat 3–5% of their body
weight in feed daily. They can convert 1.8–2.2 kg of feed into 1 kg of bodyweight. Tilapia should be fed at least
twice daily.
189
Section C: Animal production
After harvesting, live or chilled fish are sold directly to consumers or taken to
district markets. Dressed fish (cleaned and prepared fish) or fish fillets are supplied
to supermarkets, restaurants and hotels or are exported to markets abroad.
Coastal aquaculture
Coastal ponds can be used to farm marine shrimp. This type of farming depends
on the tides filling and emptying the ponds. Marine shrimp and oysters are
farmed intensively in the Bahamas, but a few other regions in the Caribbean have
developed this type of fish farming extensively. Marine tilapia are farmed in cages
off the coasts of some islands.
13.2 Factors for the keeping of bees
apiary ▶
bee selection ▶
ITQ 4
Describe how you should protect
yourself if you encounter a colony
of bees.
Bee-keeping and the production of honey is a useful form of agriculture in
developing countries. It is not too expensive to set up and it provides valuable food.
Swarms of wild bees can be collected and kept in hives made of local materials.
Alternatively, colonies of bees can be purchased. The hives can be placed in
orchards or where there are sources of nectar and pollen, such as gardens and
vegetable plots. Bees will thrive if they are kept safe and dry. Hives should be in
the shade, protected from the wind and rain and near a source of fresh water. A
group of hives is known as an apiary.
Bee selection is vital for bee-keepers. The European honey bee, common in
the Caribbean, is gentle and keeps away from people. However, the Africanised
honey bee, originating from lowland Tanzania, tends to be defensive. In Guyana,
they are known to chase people for 400 m to get them away from the colony,
and have killed approximately 1 000 people, horses and other animals. People
receive 10 times more stings from Africanised honey bees than from European
honey bees.
13.3 Economic importance of keeping bees
In many parts of the world (North America, China and Australasia), bee-keeping
is a developed industry, involving the rearing of large colonies of bees, although it
can also be done more simply.
In addition to making honey, bees are pollinators of crop plants. In commercial
apple production, many apple varieties are self-sterile and require cross-pollination
The potential for
mariculture in the Caribbean
In 2019 researchers discovered that the Caribbean region could produce at least 34 million
metric tonnes of seafood per year. Cobia, used in the research, has a high market value that is
well suited to being farmed in warmer waters. Caribbean countries currently import large amounts
of seafood; aquaculture offers the opportunity to develop the industry and provide local, sustainable
seafood. It is possible to farm the expensive cobia, make a profit and have a low environmental impact.
The aquaculture industry has a bad reputation because most of it is done on land or near the shore, where the
farms’ feed, waste and other inputs can have negative impacts on surrounding ecosystems and water quality. Deeper
water and stronger offshore currents can prevent these impacts, as well as avoiding sensitive nearshore habitats, such as
coral reefs and seagrass meadows.
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13: Fish and bee management
Africanised bees, Guyana
A garden benefits from bees visiting the flowerbeds, but hundreds of bees clustered together or seen entering and exiting
a single hidden location may be a sign of an established colony. After several deaths from swarming bees, the Guyana
Livestock Development Authority (GLDA) has issued warnings to alert people to the risk of bee colonies, especially of
Africanised bees. The Africanised bee, also known as the Africanised honey bee, and known colloquially as the ‘killer bee’, is
defined as a hybrid of the western or European honey bee species (Apis mellifera), produced originally by cross-breeding the
African honey bee (A. m. scutellata), with various European honey bees.
In Guyana, people have been urged not to swat at bees that fly around because it is most likely to provoke them and
increase the chances of being stung. The advice from the GLDA is to stay away. If you locate a hive on your property, note
its location but do not approach it. Bees are much more likely to react in defence of their hive. Call a professional. It is not
recommended that you exterminate the bees yourself. Farmers can avoid having a colony of Africanised bees by removing
potential nesting sites to reduce the chance of the bees finding a structure or cavity for a nest.
If you do encounter a colony of bees, it is advised that you run for at least 100 m. In the event of an attack,
cover your head and face, as Africanised bees tend to target these areas. Use a blanket, sheet or your
shirt to cover your head and face. If you do not have anything to cover your head and face, use your
hands to cover your face, making sure not to cover your eyes so that you can still see.
ITQ 5
Explain why apple trees need to be
pollinated by bees.
ITQ 6
Describe the features of a drone bee.
to produce a crop. Pollination is brought about by bees transferring pollen from the
flowers of one variety to the stigmas of flowers of a different variety as they visit
the flowers to collect nectar. The production of fruit crops, such as citrus, avocados,
guavas and mangoes, depends on pollination by bees. Seed production in vegetable
crops also relies on bees as pollinators.
The production of honey provides income for small farmers. Hives can be positioned
in vegetable plots, orchards and on the borders of fields.
Honey is an easily digested food and was used as a sweetener in cooking before the
extraction of sugar from sugar cane. It also treats wounds and infections of the eyes
and skin. It reduces inflammation and acts as a disinfectant.
13.4 The types of bees in a hive
In a honey bee colony, there are three types, or castes, of bee (see Table 13.2). Each
type is adapted to perform specific functions within the colony.
Figure 13.5 The three types of bee: drone,
queen and worker.
A bee colony consists of one queen, up to 50 000 workers and a few hundred
drones.
Queen
Fertile female.
Larger, longer body than worker.
Shorter wings than worker.
Sting with no barbs.
Poorly developed mouthparts; fed by workers.
Function: lays eggs; swarms.
Drone
Fertile male.
Big, broad body.
Well-developed wings.
No sting.
Reduced mouthparts.
Function: mates with the queen.
Lifespan: 5 – 6 years.
Lifespan: 4 – 5 weeks.
Worker
Sterile female.
Smaller body than either queen or drone.
Small wings.
Sting with barbs.
Mouthparts adapted for sucking up nectar and moulding wax.
Function: many functions in the hive including collection of
honey and pollen.
Lifespan: 4 – 5 weeks.
Table 13.2 Differences between the three types of bee in a hive.
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13.5 The social activities of bees
The queen
The queen is responsible for laying eggs. After she has been fertilised by the
drones, she can lay about 2 000 eggs a day. Eggs are laid singly in hexagonal (sixsided) wax cells on the combs in the brood box of a hive. Most eggs develop into
workers, but some develop into drones and a very few eggs become queens.
royal jelly ▶
The cells in which new queens are reared are bigger than the others and the
larvae are fed only on royal jelly, a nutritious substance rich in protein, which
is produced by the workers. New queens are produced only if the colony has
become large and swarming is about to take place, or if the old queen dies.
When swarming occurs, the queen and many workers leave the colony and build
a new nest somewhere else. This leaves the previous colony without a queen,
until a new one hatches from a queen cell. When the new queen emerges, she
will go on a nuptial or mating flight, mate with several drones and begin laying
eggs. Commercial bee-keepers try to prevent swarming by making sure that there
is only one queen per hive.
The drones
The drones cannot carry out many activities in the colony as they have reduced
mouthparts, so they cannot collect honey or make cells. Their main purpose is to
mate with the queen. After mating, the drones will die. If food becomes scarce,
drones are driven out of a hive by the workers.
The workers
The workers carry out many activities within the hive and also forage for honey
and pollen outside the hive. When they first hatch, young workers clean out cells
and feed older larvae on pollen and honey. As they get older, they secrete brood
food, the royal jelly, on which the young larvae and queen larvae are fed. Their
movements keep the hive warm.
ITQ 7
List the activities of the worker bees.
When workers are two weeks old, their wax glands become active and they make
wax for the construction of new cells on the comb and for repairs to older cells.
These young workers collect nectar and pollen from the foraging worker bees and
store it. They convert nectar into honey by reducing the water content.
After three weeks, workers become foragers and leave the hive in search of nectar.
These forager worker bees are able to communicate the location of sources of
nectar to other foraging bees by performing special ‘dances’ to show the direction
and distance of the source from the hive. In addition to nectar, foraging bees also
collect pollen, water and propolis (a sticky substance collected from tree buds
which is used to seal cracks in the hive).
Figure 13.6 Varroa mites clinging to a
bee larva.
192
The social organisation of the colony is controlled by chemicals secreted by the
queen, called pheromones. These get passed from the queen to the workers and
control their behaviour.
13: Fish and bee management
13.6 Pests and diseases of bees
A number of pests and diseases affect bees. However, they are not widespread
in the Caribbean because the islands maintain natural barriers to infection. Beekeepers need to take care to not allow transference of these infections through
the supply of bee-keeping materials from infected areas.
Disease
Foulbrood: caused by a
spore-forming bacterium.
Symptoms
• The larvae die within the capped (sealed) cells of the comb,
which first become slimy, then dry out and turn dark brown.
These cells produce a foul smell, which gives the disease its
name.
• The disease can be detected by inspecting combs of the brood
box for any discoloured or brown cells. The condition can be
treated with antibiotics that are added to the hive, but this
does not kill the spores, it only delays their growth.
Acarine mite infestation:
the mites are tiny
arthropods (related to
spiders).
• The mites get into the breathing tubes of young adult bees
in the first week after hatching, before the bees have left the
hive, so the spread of the infestation depends on the young
bees being in contact with older, infested bees.
• The affected bees have distended abdomens and their wings
take on a different shape, causing them to flutter.
• As the life of a worker is short, infestations are usually not
serious and do not affect honey production.
Dysentery.
• Dysentery is suspected when the hive contents are soiled by
the faeces of the bees.
• A build-up of faeces in the hive may be caused by too much
water in the food for bees that are confined to the hive (over
winter).
Varroasis: infestation by • These mites feed on the body fluids of bees and can be seen
the Varroa parasitic mite,
as small brown spots on the bee’s thorax.
which carries a virus that • Severe infestations result in the death of whole colonies so
causes deformed wings
bee-keepers need to inspect hives regularly for signs of the
in adult bees.
mites. Mites may be present in sealed brood cells.
Prevention and management
• Spores are resistant to heat, cold and disinfectants.
They remain viable for years in old combs, in honey
and on equipment.
• The best preventive measures are strict cleanliness,
regular inspection of the brood in the hives and
sterilisation of all equipment. Clothing should be
thoroughly washed in hot, soapy water.
• Do not feed infected honey to young larvae.
• Do not use second-hand equipment.
• Do not move combs from an infected hive to an
uninfected one.
• Treatment involves a smoke strip, which is lit and
allowed to hang down so that smoke circulates quickly
around the hive. The bees are prevented from leaving
the hive while the smoke circulates. This smoke is
toxic to mites, but harmless to the bees, the brood and
the stores of honey and pollen.
• If bees are confined to the hive during poor weather,
infestations may become more serious and need
treatment.
• Bees should be fed only refined beet sugar or refined
cane sugar: brown sugar or raw sugar causes excess
water and the possibility of dysentery.
• The condition is not serious in itself, but it can worsen
other infections.
• Mites can spread when components of a hive are
interchanged during management of the colony.
• Movement of hives and queen bees also spreads
an infestation. Infested apiaries should be isolated.
Affected bees, combs and other components of a hive
should be destroyed.
• If the disease becomes widespread, chemical controls
that kill mites can be applied in the form of aerosol
sprays. Tobacco smoke also works. These treatments
are expensive and may leave residues in the honey.
Table 13.3 Diseases, symptoms and prevention methods.
13.7 Honey and other bee products
Honey
ITQ 8
List THREE diseases that affect bees.
In managed hives, honey is stored in the cells of the combs in the supers in a
hive. Supers are removable sections of a managed beehive that are used to hold
frames of combs that contain mostly honey. The supers are usually at the top of
a managed hive. When honey is the right consistency, bees cap (close off) the
cells with wax. Any uncapped cells are likely to contain ‘unripe’ honey. The best
way to extract honey from a comb is by using a machine called a spinner. These
are expensive, but it is possible to hire one or join with other bee-keepers for a
honey-spinning session using a communal machine.
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Section C: Animal production
The procedure involves these steps.
• The spinner is cleaned thoroughly with boiling water.
• The spinner is dried.
• The wax capping on the cells on both sides of the comb in a frame is removed.
This is done by running a sharp knife over the surface to cut off the caps. The
wax caps are scraped onto a tray. If the scrapings are heated, residual honey
can be separated from the wax. The wax can be saved and used later.
• The uncapped frames of combs are placed in the spinner. Many spinners will
take up to four frames.
• To extract the honey, the spinner starts to rotate slowly, gradually working
up to full speed. After two minutes, the frames are turned around and spun
again. It takes five minutes for the honey to be removed from the frames.
• The frames are removed from the spinner. There will still be some honey left
in the frames but they can be put back into the super and returned to the
hive. The bees will use the rest of the honey on the frames.
Figure 13.7 Using a sharp knife to remove
the wax cappings from a honey comb.
ITQ 9
Describe how honey can be removed
from a comb by a spinner.
As an alternative to using a spinner, honey can be removed from a comb by
simply scraping it off with a spoon. Using this method, the honey will be mixed
with pollen, wax and bits of dead bees. Pieces of comb can also be cut out and sold
as ‘comb honey’, but this will also have pollen in it.
After the honey has been extracted, it will need to be bottled. If a clear honey is
desired it must be filtered, either through damp muslin (a thin cloth) or through
stainless steel filters. The filtered honey is poured into clean, dry jars and the lids
screwed on. If the honey is to be sold commercially, there are regulations about
extracting and labelling it. Extractors must be made of plastic or stainless steel and
labels need to state the name of the producer and the weight of the honey.
Beeswax
Practical activities:
1. Visit a bee-keeper and observe
the activity in the hives. Wear
protective clothing in case the
bees try to sting you.
2. Collect pictures of the
equipment used in bee-keeping
and find out how much honey
is produced in your area.
Research bee-keeping using
the internet and locate your
local bee-keepers’ association.
The association can help you.
3. Visit local food stores and
pharmacies to find out whether
bee products are available.
194
Beeswax is secreted from wax glands on the underside of the abdomen on a
worker bee. The wax is used to construct cells to hold eggs, honey and pollen.
Bee-keepers can collect wax from the combs when honey is extracted, but the
wax has to be cleaned before use.
There are various methods of wax extraction, but the simplest way is to put the
wax on a metal grid over a tray, cover it with a transparent lid and leave it in
a sunny place. As the temperature rises, the wax melts and it can be filtered
and allowed to drip into a container. This procedure should be watched. If the
temperature gets too high, the wax will burn.
Beeswax can be used for:
• candles
• cosmetics
• crayons
• paints and varnishes
• coatings for washable wallpaper
• floor polish and car wax.
13: Fish and bee management
Medicinal products
Honey has been used to treat infections and reduce inflammation, but other
products from beehives also have medicinal properties. Not all the claims made
are true, but the products are used as natural remedies and do work for some
people. None of the products are harmful.
ITQ 10
Give FOUR uses of beeswax.
propolis ▶
Propolis is the sticky substance used by bees to seal cracks, line the hive and cells
and mend the combs. It is collected from the bark and buds of trees. Propolis can
be removed from hives by scraping. It has been used as an antiseptic and is now
marketed as an ointment, as lozenges and in capsules. It is said to help throat
infections, the common cold, mouth problems, some skin conditions and stomach
ulcers.
pollen ▶
Pollen contains carbohydrates, proteins, vitamins and minerals. It is used by bees
to make brood food on which larvae and young bees are fed. It can be collected
by fitting a device to the hive entrance that scrapes pollen from the legs of bees.
Various claims have been made about the benefits of eating pollen, and it has
been used to protect against hayfever.
Royal jelly is the milky liquid that worker bees make and feed to the young larvae.
All young larvae are fed on this for a few days. After this time, only those larvae
destined to be future queens are fed on it. Jelly is collected from queen cells by
removing larvae and scooping out the contents. Commercial production involves
rearing many queen larvae as only about 25 g can be collected from 100 queen
cells. It is therefore very expensive.
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Section C: Animal production
Revision map
Do not need
much labour
Systems
are cheap
Fish being
taken from a local
river and placed
in ponds
Do not need
much additional
food for
the fish
Brackish
water
Freshwater
Seawater
Extensive
aquaculture
systems
Three
main aquatic
environments for
aquaculture in the
Caribbean
Aquaculture
is the cultivation
of selected aquatic
plants and animals
in water
Tanks or ponds
with strictly controlled
conditions to ensure
maximum growth
of fish
Temperature
Intensive
aquaculture
systems
Aquaculture
Conditions
that are
monitored
Coastal
aquaculture and
mariculture have the
potential for
development in the
Caribbean
pH
Fish and
bee management
Apiculture
is bee-keeping
and the production
of honey
Not too
expensive
to set up
Apiculture
Useful form
of agriculture in
developing
countries
There are three
types of bee in a hive
these undertake different
activities to maintain the
colony, as well as make
honey and other
products
Provides
valuable
food
Bees pollinate
crops by transferring
pollen from the flowers
of one variety to the stigmas
of flowers of a different variety
as they visit the flowers
to collect nectar
Products
made by bees and
harvested for use
by people
There are several
pests and diseases
that affect bees
Queen
Worker
196
Drone
Royal jelly
Beeswax
Propolis
Pollen
Oxygen
levels
13: Fish and bee management
Examination-style questions
Multiple-choice questions
Write down the number of the question followed by the letter of the correct answer.
1.
2.
3.
4.
Which of the following would you expect to find in brackish water?
A Oyster
B Cascadura
C Cobia
D Lobster
A worker bee is a:
A fertile female
B fertile male
C sterile female
D sterile male.
Which of the following activities is NOT carried out by the workers?
A Laying eggs
B Cleaning cells
C Collecting nectar
D Feeding larvae
Which bee product can be used to make coatings for washable wallpaper?
A Propolis
B Royal jelly
C Honey
D Wax
Short-answer and essay-type questions
5.
(a) Describe how to set up an intensive fish farm.
(b) Explain how to manage an intensive fish farm.
6. Describe how the development of mariculture may benefit (a) the economy, and (b) the
local environment.
7. Explain why bee-keeping is of economic importance.
8. (a) Describe how honey can be extracted from a comb.
(b) Describe the uses of THREE bee products other than honey that can be extracted
from hives.
9. (a) Explain how a worker is different from other types of bee.
(b) Describe the activities of worker bees in a hive.
10. (a) Explain what swarming is.
(b) Describe how to protect yourself from swarming bees.
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Section C: Animal production
14
Animal
genetics,
breeding and
reproduction
By the end of this unit you should be able to:
✔
✔
✔
✔
✔
✔
✔
✔
✔
Concept map
198
Animal genetics, breeding and reproduction
Breeding
systems
Genetic
engineering
Cross-breeding
Inbreeding
Upgrading
Back-crossing
Hybrid vigour
Disease resistance
Improved production
Methods of
gene transfer
Concerns
Benefits
Genetic
improvement
Performance resting
Embryo transfer
Progeny testing
Heritability
explain different breeding systems in animal production
explain the advantages of cross-breeding
explain genetic engineering in livestock production
differentiate between the terms: (a) ovulation; (b) fertilisation;
(c) gestation; (d) oestrous cycle; (e) kindling, parturition, farrowing
describe the process of artificial insemination (AI) in farm animals
evaluate the use of AI in farm animals
state the benefits of oestrus synchronisation
relate the structure of the parts of an egg to its function
describe the process of incubation in poultry.
Enhanced nutrition
Reduced environmental
impact
Enhancing milk
Enhancing growth rate
Improved disease resistance
Improved hair and fibre
Terms used in
reproduction
Ovulation
Fertilisation
Gestation
Oestrous cycle
Signs of heat
Parturition
Kindling
Farrowing
Artificial
insemination (AI)
Advantages
Disadvantages
Structure of
an egg
Egg formation
and incubation
in poultry
Artificial
incubation
Candling
14: Animal genetics, breeding and reproduction
14.1 Breeding systems in animal production
Breed
breed ▶
breeding system ▶
A breed is a group of animals of the same species that have certain characteristics
in common. These characteristics are usually physical ones, such as coat colour
or shape of the body, but they may also be behavioural characteristics, such as
docility. Different breeds have developed as a result of the selection of desirable
characteristics by farmers and breeders or by cross-breeding. A breeding system
involves the mating of a male animal with a female animal. Both animals are
chosen for their desirable characteristics.
When breeders want to produce more suitable animals, they must decide which
characteristics are important. Variation among individual animals of a particular
breed is influenced by their genotype and the environment. For example, dairy
cows are bred for their high milk yields, but if the cows are put on poor pasture
their yields will not be as high as those cows fed on a better diet. If the breeder
is hoping to breed an animal that will increase its productivity, he or she needs
to know what proportion of the desired characteristic is influenced by genotype,
rather than by the environment.
heritability ▶
continuous variation ▶
variety ▶
cultivars ▶
The effect of genes on a characteristic is referred to as heritability. Many
important characteristics, such as milk yield, carcass quality and rate of growth,
are controlled by more than one pair of genes. These characteristics show
continuous variation and there may be a wide range of values across the breed.
Each gene may have a small effect on milk yield, for example, but several genes
combine to have a cumulative effect. It is possible to calculate the heritability
of a characteristic, such as milk yield, by keeping records of the volume of milk
produced by each cow and then determining the average for each individual and
the average for the herd. Cows that have averages above the herd average would
be the ones to use for breeding if the farmer wants an increased yield.
When referring to different types of crop plants of the same species, the term
variety is used instead of breed. Varieties, or cultivated varieties, are often
referred to using the shortened form, which is cultivars.
Cross-breeding
cross-breeding ▶
hybrids ▶
Cross-breeding occurs when an animal is mated with another animal of the same
species but of a different breed. For example, Hereford cattle may be mated with
Aberdeen Angus cattle to give offspring with an increased growth rate. Animals
that are cross-bred often show increased vigour and productivity. The genes from
the two breeds are combined. Characteristics controlled by the dominant genes
from both breeds tend to be expressed. The offspring of cross-breeding are called
hybrids.
Inbreeding
inbreeding ▶
inbreeding depression ▶
Inbreeding occurs when animals of the same breed are mated with one another.
These animals will be closely related and genetically similar to one another. Animal
breeders use inbreeding to produce superior offspring (in the short term) and
to maintain desirable characteristics within the breed. However, there are some
risks attached to inbreeding. If inbreeding is used for many generations, there
is actually a decrease in desirable characteristics and an increase in undesirable
characteristics. This is known as inbreeding depression. Inbred animals may
show a decreased resistance to infection, be smaller in size, show physical defects
and have a shorter lifespan.
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Section C: Animal production
Cross-breeding in the Caribbean
Some breeds have been developed especially for the Caribbean region by
cross-breeding. The breed of cattle called Jamaica Hope was developed in
Jamaica by crossing Zebu cattle from India with Jersey cattle from Europe.
The resulting breed is a good milk producer and is resistant to some diseases.
Similarly, Jamaica Red and Jamaica Black cattle were developed from
Aberdeen Angus cattle for good meat production. In Trinidad and Tobago,
the Buffalypso was developed by crossing different breeds of river buffaloes.
The resulting meat is of a higher quality than the top cuts of prime beef,
and breeding stocks have been exported to other Caribbean countries.
The Barbados Black Belly sheep are reared for their meat and are
probably derived from sheep brought by settlers to the
islands. They tolerate heat and have coats of coarse
hair, not wool.
Figure 14.1
Buffalypso, Trinidad.
Upgrading
upgrading ▶
Upgrading involves crossing native, or local, breeds with breeds from other
countries or regions of the world. Farm animals that thrive and have high
productivity in a temperate climate, such as those found in Europe, do not always
adapt well to a tropical climate. Their food sources may differ and they cannot
tolerate the heat as well as the local breeds can. They also have less resistance to
the pests and diseases that affect local breeds.
For these reasons, cross-breeding of local breeds with high-producing imported
breeds can have advantages. Desirable characteristics of the imported breed can be
introduced into a local breed. A good example is the development of the Jamaica
Hope dairy cattle and the Jamaica breeds of beef cattle.
Back-crossing
back-crossing ▶
ITQ 1
Explain the difference between crossbreeding and inbreeding.
ITQ 2
Describe ONE example of upgrading
that has produced a breed of farm
animal adapted to the Caribbean.
Back-crossing is the term given to the crossing of a hybrid organism with one
of its parents. It can be used in both plant and animal breeding programmes, but
it has been more frequently applied in the development of crop plants. This type
of cross is carried out to obtain offspring that are similar to the parent with the
desirable characteristic.
Back-crossing can maintain desirable characteristics in a breed and does not
introduce new genes. However, it does not work well for characteristics such as
growth rate, nor does it work for recessive genes.
14.2 Advantages of cross-breeding
Hybrid vigour (heterosis)
hybrid vigour, heterosis ▶
200
Cross-breeding involves mating animals from different breeds of the same species.
It combines the genes of the two breeds. The resulting offspring have an increase
in heterozygous genes. Hybrid offspring may be more fertile and have a longer
lifespan than their parents. The increased fitness of the hybrid generation is called
hybrid vigour or heterosis.
14: Animal genetics, breeding and reproduction
Most desirable characteristics are controlled by dominant genes, and hybrid
vigour results from an increase in heterozygous genes. Undesirable characteristics
are often controlled by recessive genes. An increase in heterozygous genes means
that these characteristics do not show in the hybrid offspring.
Parent genotypes: Breed X
AAbb
Gametes
×
Ab
Breed Y
aaBB
aB
Gametes
aB
aB
Ab
AaBb
AaBb
Ab
AaBb
AaBb
Genotype of offspring: AaBb
Phenotype of offspring: Potential to produce large
litters with a high percentage survival.
Figure 14.2 A genetic cross diagram
demonstrating hybrid vigour.
An example of how an increase in heterozygosity can benefit a breed can be
shown by crossing two breeds of pigs. Breed X sows produce large litters but the
survival rate of the piglets is low. Breed Y sows have fewer piglets in each litter but
the survival rate of the piglets is high. Large litters are controlled by the dominant
allele A and percentage survival is controlled by the dominant allele B. If a purebreeding sow from Breed X is crossed with a pure-breeding boar from Breed Y,
then the piglets will show hybrid vigour. This is shown in Figure 14.2.
Examples of hybrid vigour in farm animals include:
• milk yield and butterfat content of milk in dairy cattle
• carcass composition and weight gain after weaning in beef cattle
• litter size and growth rate in pigs
• carcass weight in sheep.
Disease resistance
An inbred resistance to disease in farm animals means that farmers depend less on
the use of drugs to treat diseases. There is therefore a decreased risk of these drugs
getting into human food. The benefits to farmers are that veterinarian’s bills and
production costs are lower. In addition, disease resistance reduces the chances of
pathogenic organisms becoming resistant to drugs.
Many people think that if animals are kept healthy and reared under good
conditions, they are less likely to suffer from diseases. This is true, but resistance
to some diseases is also inherited.
It would be difficult to breed animals that are resistant to all diseases. However,
there has been some progress in selecting breeds that show resistance to conditions
such as:
• mastitis and respiratory diseases in cattle
• Salmonella and E.coli in pigs
• footrot and scrapie (a viral disease) in sheep
• certain parasites.
ITQ 3
Explain what is meant by hybrid
vigour.
The Jamaica Hope breed is an example of selection for disease resistance. Zebu
cattle have some resistance to parasitic ticks and the diseases they carry. When
Zebu cattle were crossed with Jersey cattle, the resulting hybrids also showed
increased resistance to ticks.
Improved production
Cross-breeding will result in improved production in farm animals if breeds with
desirable characteristics are chosen. Cross-breeding results in increased vigour of
the offspring. It also improves survival rate and leads to faster growth rates. A
farmer or animal breeder will always choose the fittest animals from which to
breed, therefore continuing the improvement of the stock.
Genetic improvement
When attempting to improve breeds of farm animals, it is necessary to:
• identify desirable characteristics
• keep accurate records of animal performance
• select animals for breeding.
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Section C: Animal production
GloFish
Genetically modified zebra fish, called GloFish, show red, green or orange fluorescence. These were
developed to monitor water pollution. The fluorescence is caused by a gene originally isolated from
jellyfish. The GloFish have been marketed and sold as pets in the USA.
genetic improvement ▶
These principles of genetic improvement have been used by animal breeders
for many decades, but an understanding of genetics has increased the rate of
improvement. We can now identify which characteristics are inherited and which
are due to the effects of the environment.
Desirable characteristics are those that increase productivity for the farmer. More
income can be derived from hens that lay more eggs, cows that produce more
milk and beef cattle that have a fast growth rate and a good carcass shape.
performance testing ▶
embryo transfer ▶
progeny testing ▶
Performance testing
Performance testing involves comparing the productivity of animals kept
under the same conditions. It applies to characteristics that can be measured, such
as milk yield, number of offspring and survival rates. Records of performance are
useful, not only for identifying which animals are good producers but also for the
farm accounts. The benefits of record-keeping will be described in Unit 18.
Embryo transfer
The selection of animals for breeding is mainly based on their performance.
Traditionally, good dairy cows have been used for breeding, but a cow will produce
only about eight calves in her lifetime, and half of them could be male. Nowadays,
‘desirable’ cows can be made to produce many embryos, which are transferred to
the uterus of another cow or deep frozen for later implantation. This technique
is known as embryo transfer. It increases the number of offspring from the
‘desirable’ cow.
Progeny testing
Desirable female characteristics, such as good milk yield in cattle, cannot be
assessed directly from a bull’s phenotype. So bulls are mated with several cows
and the performance of their daughters is compared in a process called progeny
testing. If the outcome is favourable, then the bull can be mated and pass his
genes on to a large number of offspring. Use of artificial insemination (AI), where
one bull’s semen (fluid containing sperm) can be used to fertilise many cows,
means that a good bull may produce thousands of offspring in a year.
Heritability
When assessing fitness for breeding, the heritability has to be considered.
Heritability is the effect of the genes on the desired characteristic. If a breeder
knows the approximate heritability of a characteristic, he or she will have some
idea as to whether selection for improvement of that characteristic is likely to
be successful. The higher the heritability percentage, the greater the chance that
selection for the characteristic will result in improvement. For example, postweaning increase in weight in sheep has a heritability of 60%, but fleece weight
has a heritability of 17%. Of course, there will always be variation within a
breed of farm animals and that variation will be different in different groups of
the same breed.
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14: Animal genetics, breeding and reproduction
14.3 Genetic engineering in livestock
production
genetically modified organism (GMO) ▶
transgenic organism ▶
A genetically modified organism (GMO) is an organism whose genes have
been altered by genetic engineering. A transgenic organism contains genes that
have been transferred into it from another species. This technology has been used
successfully in plant breeding and it has the potential to improve productivity in
farm animals.
The production of transgenics provides methods to rapidly introduce ‘new’ or
modified genes and DNA sequences into livestock without cross-breeding or
hybridising. It is a more precise technique, but not fundamentally different from
genetic selection or cross-breeding in its result.
Methods of gene transfer
Two methods of gene transfer are described in the following points. Figure 14.4
illustrates the details of the techniques involved.
• Direct injection into the nucleus of a fertilised ovum: The desired gene is
isolated and injected using a very fine pipette. The fertilised ovum develops
into an embryo, which can be implanted into a surrogate mother to produce
an offspring. The offspring will be transgenic if the gene has been transferred
successfully.
• Using a virus: The selected gene is first inserted into a virus. An embryo at the
4–8 cell stage is then infected with the virus. The virus infects the embryo and
the selected gene is added to the DNA of the embryo’s cells. The embryo is
then implanted into a surrogate mother where it develops into an offspring.
Concerns about genetic engineering
Genetic engineering is more advanced in the area of crop breeding than in animal
breeding. However, many people have expressed concerns about the effects of
‘interfering with nature’.
• Most of the concerns have been about the safety of food produced from
genetically modified (GM) crops. Testing has shown that, so far, there are no
toxic effects and the nutritional value is equivalent to food from non-GM crops.
• Any food that contains, or is derived from, genetically modified organisms has
to be clearly labelled.
• Religious views vary. No foods have been described as unacceptable, but any
use of genes from pigs is not acceptable to Jewish or Muslim people. The
Catholic Church is against the genetic engineering of embryos.
Herman the Bull
In another experiment, the human gene for lactoferrin, which is a protein with
anti-microbial properties found in milk, was inserted into a male embryo from
a cow. This embryo developed into a calf and eventually into a bull named
Herman. When Herman was mature, a breeding programme was set up and
he was allowed to mate. All calves produced by Herman carried the human
lactoferrin gene. After this experiment, Herman was not allowed to mate again
and was eventually slaughtered as he suffered from osteoarthritis. At the time
of this experiment, there were concerns raised about the transfer of human
genes in this way.
Figure 14.3
Herman the Bull.
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Section C: Animal production
• Many people also worry about genes that may have undesirable effects getting
into other plants. There is, for example, a possible risk of cross-breeding GM
maize with unmodified maize, but most experimental work on these crops is
carefully controlled.
(a)
Benefits of genetic engineering
The benefits to food production worldwide could be immense as the technology
improves. With testing and controlled use, there could be significant improvements
in the quantity and the quality of food produced. The need to use excessive
amounts of pesticides would also be reduced if crops had genes for disease
resistance bred into them.
Enhanced nutrition
Transgenic technology could provide a way to transfer or increase nutritionally
beneficial traits. For example, transfer of a transgene that increases the levels of
omega-3 fatty acids in pigs may improve the nutritional quality of pork. Lower fat
and more nutritious pork products could then improve human health.
(b)
virus
Figure 14.4 Gene transfer by injection of
the desired gene into a fertilised ovum (top)
and gene transfer using a virus (bottom).
Reduced environmental impact
Transgenic livestock has the potential to dramatically reduce the environmental
footprint of animal agriculture. Increasing efficiency and productivity through
transgenesis could decrease the use of limited land and water resources while
protecting the soil and ground water. For example, pigs do not fully use dietary
phosphorus. High levels of phosphorus in waste products can cause pollution
problems. The phytase gene results in transgenic pigs using up to 75% of dietary
phosphorous, therefore decreasing phosphorus pollution to the environment
from commercial pig farms.
Improved production efficiencies of milk and meat would decrease the amount
of manure, slow the direct competition for human food, decrease the amount of
water required for the animals and the production facilities and decrease the land
necessary for livestock operations.
Enhanced milk
Advances in transgenic technology provide an opportunity either to change
the composition of milk or to produce entirely new proteins in milk. The major
nutrients in milk are protein, fat and lactose. By elevating any of these components,
it can impact the growth and health of the developing offspring.
Enhanced growth rates and carcass composition
It is possible to manipulate growth factors, growth factor receptors and growth
modulators through the use of transgenic technology. In the case of fish, there
is a need for more efficient and rapid production, without diminishing the wild
stocks, to provide a protein source for the increasing world population. The
production of growth hormone transgenic fish has led to dramatic (30 – 40%)
increases in growth rates in catfish through the introduction of salmon growth
hormone into them.
ITQ 4
Describe how viruses are used
to introduce new genes into an
organism.
204
Improved disease resistance
Genetic modification of livestock will enhance animal welfare by producing
healthier animals. For example, mastitis in cows is an inflammation of the
mammary gland, caused by bacteria. Mastitis causes decreased milk production.
It has been found that transgenic dairy cows that secrete the hormone lysostaphin
into their milk have higher resistance to mastitis because the lysostaphin kills the
bacteria that cause mastitis.
14: Animal genetics, breeding and reproduction
Practical activity:
Carry out an internet search
for recent information on the
genetic modification of livestock.
Collect information and make a
presentation to the rest of the class.
Improved hair and fibre
Spiders that produce orb-webs create as many as seven different types of silk for
making these webs; this silk can now be produced using transgenic goat milk.
One of the most durable varieties is dragline silk. This material can be elongated
up to 35% and has tensile properties close to those of carbon fibre. Its energyabsorbing capabilities exceed those of steel. These fibres could be used in medical
sutures, ballistic protection, airbags, aircraft, automotive composites and clothing.
14.4 Terms used in animal reproduction
Ovulation
spontaneous ovulation ▶
induced ovulation ▶
Ovulation occurs at the ovary surface and is the process whereby an oocyte
(female germ cell) is released from the follicle. Spontaneous ovulation is the
process where species go through menstrual cycles and are fertile at certain times
based on what part of the cycle they are in. Species in which the females are
spontaneous ovulators include cattle, sheep and humans. Cattle are naturally
spontaneous ovulators; however, in dairy farming there is often a need to induce
ovulation to improve the fertility of a herd, and therefore increase the efficiency
of the farm.
Induced ovulation is when a female animal ovulates due to an externally
derived stimulus during, or just before, mating, rather than ovulating cyclically or
spontaneously. Species where the females are naturally induced ovulators include
cats, rabbits, goats and horses.
Fertilisation
fertilisation ▶
zygote ▶
Fertilisation is the process in which the male gamete (sperm) fuses with the
female gamete (ovum) to form a zygote, which, through cell division, becomes
the embryo.
In farm animals, fertilisation (conception) can only occur when the female animal
comes on heat, ovulates and is mated or artificially inseminated. At the time of
mating or artificial insemination, large numbers of sperm are deposited in the
female reproductive tract and swim up the oviduct towards the ovum. Fertilisation
occurs halfway down the oviduct when one sperm fuses with an ovum shed from
the ovary. The fertilised egg, now called a zygote, moves into the uterus where it
becomes implanted in the uterus wall and eventually develops into the offspring.
Gestation
gestation ▶
Gestation is the period between conception (fertilisation) and the birth of the
young animal (parturition). It varies in length with the different classes of farm
animal (see Table 14.1).
Class of livestock
Cattle: Cow
Sheep: Ewe
Pig: Sow
Goat: Doe
Rabbit: Doe
Length of gestation period (days)
Average
280
148
114
150
30
Range
277 – 283
145 – 151
110 – 117
147 – 153
28 – 32
Table 14.1 The gestation periods of some farm animals.
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Section C: Animal production
Throughout the gestation period, pregnancy is maintained by the corpus luteum
in the ovary, which produces the hormone progesterone.
The farmer can recognise that an animal is pregnant because:
• there is an absence of heat (the non-pregnant cow would show signs of heat
19–23 days after insemination)
• the abdomen changes in size, becoming wider or ‘bellying down’
• the mammary organs (udders, teats and milk veins) develop.
The farmer can find out whether a cow is pregnant by getting a veterinarian or
a trained livestock technician to palpate (feel a body part) the uterine horns 3–4
months after mating. This is done through the rectum and enables the developing
calf to be felt. More recently, pregnancy detection kits have been developed.
These measure progesterone levels in milk samples and these kits can be used
by farmers. These kits are accurate, inexpensive and can be carried out in early
pregnancy, so the farmer can organise another insemination if the cow is not
pregnant.
foetus ▶
During pregnancy, the embryo becomes implanted into the wall of the uterus and
membranes develop around it. The placenta develops and enables nutrients and
oxygen to pass from the mother to the growing embryo, which is now called a
foetus. Waste materials from the foetus pass across the placenta into the blood
of the mother.
The oestrous cycle
oestrous cycle ▶
oestrus ▶
Ovulation is the release of an ovum from the ovary. It is closely associated with
the heat period. It usually occurs during oestrus or shortly after it. Mating during
this time can result in fertilisation and pregnancy.
ITQ 5
Define ovulation.
oestrus synchronisation ▶
2. oestrus
1. proestrus
3. metoestrus
4.dioestrus
Figure 14.5 The phases of the oestrous
cycle.
206
The oestrous cycle is a sequence of events occurring in female mammals. The
cycle is the number of days from the beginning of one heat period (oestrus) to
the beginning of the next heat period. The heat period is the length of time during
which the female farm animal is sexually receptive to the male farm animal. The
oestrus cycle is controlled by hormones. Once puberty is reached, female farm
animals come into heat at regular intervals. It is only during the period of heat
that the female allows herself to be serviced by the male. Heat occurs as a result of
the large amount of the hormone oestrogen, produced by the ovaries, circulating
in the blood.
Oestrus synchronisation is where female mammals are targeted to come into
heat in a short period of time through the use of hormones. The benefits are that
dairy and beef cattle can be managed with appropriate nutrition, without wasting
feed costs. Further benefits are that a bull can be optimised during this time, or
expensive AI treatment could potentially have a higher success rate.
The oestrous cycle can be divided into four phases (see Figure 14.5).
• Proestrus: Proestrus is influenced by oestrogen, which prepares the
reproductive system for oestrus and stimulates the growth of ovarian follicles
and the development of ova.
• Oestrus (the heat period): This phase is also influenced by oestrogen, which
causes the female to be sexually receptive for mating. It may result in
ovulation.
14: Animal genetics, breeding and reproduction
• Metoestrus: Ovulation may occur at the beginning of this phase. After an
ovum has been released from its follicle, a corpus luteum develops. The
hormone progesterone begins to be produced by the corpus luteum. Less
oestrogen is released.
• Dioestrus: If fertilisation does not occur, the corpus luteum breaks down and
there is a short period of inactivity before a new proestrus phase begins.
The duration of the oestrous cycle and the time of ovulation vary across the classes
of livestock (see Table 14.2).
Class of livestock
Cattle: Cow
Sheep: Ewe
Pig: Sow
Goat: Doe
Length of oestrus cycle
(days)
avg.
range
21
18 – 24
17
14 – 20
21
18 – 24
20
19 – 21
Duration of heat or oestrus
(hours)
avg.
range
19
12 – 28
38
24 – 48
60
24 – 96
39
24 – 96
Time of ovulation (hours)
avg.
12
38
36
36
range
10 – 16 hours after end of oestrus
36 – 40 hours after beginning of oestrus
30 – 40 hours after beginning of oestrus
12 – 36 hours after beginning of oestrus
Table 14.2 The oestrous cycles of different classes of livestock.
Signs of heat
ITQ 6
List THREE signs of heat shown by
a cow.
When female farm animals come on heat, they usually display recognisable signs
(see Table 14.3). It is important to look out for these signs so that the females
can be serviced by the males at the correct time for fertilisation to occur. This
is particularly relevant to cattle because milk production depends on the cows
producing calves.
Class of animal
Cattle: Cow
Goat: Doe
Sheep: Ewe
Pig: Sow
Signs of heat (oestrus)
Restless; swollen and / or reddened vulva; slimy mucus discharge from
the vulva; persistent mooing or bellowing; animal allows other cows to
mount her; milk yield drops; loss of appetite.
Restless; vulva becomes enlarged or swollen; slimy mucus discharge from
the vulva; persistent bleating; stands to be mounted by the buck; shakes
tail vigorously.
Often does not show visible signs but rams can detect when ewes are on
heat.
Restless; grunts; vulva becomes reddened and swollen; slimy mucus
discharge from the vulva; stands to be mounted by the boar.
Table 14.3 Signs of heat in some female farm animals.
Parturition
parturition ▶
Parturition (the birth process) occurs at the end of the pregnancy. This is the
time when the female animal gives birth to her young. This process is influenced
by hormones such as oxytocin and relaxin.
Parturition can be divided into several stages.
• Just before parturition, the animal may become restless. She will look for a
quiet area, and will try to urinate frequently. In cows, there is a thick mucus
discharge from the vulva.
• Uterine contractions occur as a result of the secretion of the hormone
oxytocin.
• The cervix and pelvic region dilate (widen) under the influence of relaxin.
• The offspring is delivered through the birth canal.
• The placenta (afterbirth) is delivered shortly after the offspring.
Figure 14.6 A newly born lamb.
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Section C: Animal production
The farmer or a farm attendant should always be present at parturition to help the
animal. It may be necessary to:
• remove mucus from the mouth and nostrils to enable the young animal to
breathe easily
• dry the young animal if the mother has not already done so
• make sure that the umbilical cord is not wrapped around the neck of the
young animal
• cut the umbilical cord, using the correct procedures
• make sure that the mother suckles the young animal soon after birth so that
the young animal gets the colostrum (first milk after parturition). Colostrum
contains antibodies that will protect the young animal from infection.
ITQ 7
Explain why colostrum is so
important.
Kindling
kindling ▶
Kindling is the term used to describe the process of giving birth in rabbits. It
takes place 30 days after a successful mating of the doe with the buck. About five
days before the doe is due to kindle, she will carry straw around and build a nest.
A nest box should be placed in the rabbit pen three days before kindling is due.
Farrowing
farrowing ▶
Practical activity:
Visit livestock farms and, if possible,
observe signs of heat in the farm
animals. Record your observations in
a table.
mating ▶
artificial insemination ▶
Farrowing is parturition in pigs and takes place about 115 days after mating.
Two weeks before farrowing, the mammary glands of the sow develop, the teats
enlarge and veins supplying the udders become prominent. The farrowing process
lasts 3–8 hours, with piglets delivered at 10 – 20 minute intervals. When all the
piglets have been delivered, the placenta is expelled.
14.5 Artificial insemination in farm animals
Mating in livestock farming refers to bringing together mature male and female
animals of the same species for the purpose of breeding. Female animals that
come on heat may be bred or serviced naturally by the male (boar, bull, ram or
buck). As an alternative, semen from the male can be obtained and introduced
into the reproductive tract of the female on heat through the process of artificial
insemination (AI). This is a technical process that needs to be carried out by a
trained inseminator. Artificial insemination is carried out in cattle, sheep, goats
and pigs.
The semen is collected from pedigree or proven male animals, chosen for their
desirable characteristics. An electrical stimulation device or a massage method may
be used to make the male animal ejaculate (eject semen) into an artificial vagina,
which collects the semen. A single ejaculation has an average volume of 5 ml, and
contains approximately 5 billion sperm. The sperm count of the semen is calculated
and quality-control checks are done to detect any abnormalities or diseases.
Figure 14.7 Collecting semen from a
pedigree bull.
The semen is then diluted with a solution containing:
• sugar
• salts that maintain the correct pH
• glycerol to protect the sperm against the effects of freezing
• antibiotics to prevent the growth of bacteria.
The semen is divided into small quantities, 0.25 – 0.5 cm3, and packed into
disposable plastic straws. The straws are stored by freezing in liquid nitrogen at
–196 °C. The straws can be used to service hundreds of female animals (cows,
ewes, sows, does) worldwide.
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14: Animal genetics, breeding and reproduction
The straw containing semen is thawed and the contents placed into a glass or
plastic pipette. The pipette is inserted into the vagina of the female animal on
heat. The inseminator, wearing long plastic gloves, places a hand into the rectum
to manipulate the reproductive tract and guides the pipette so that semen is
deposited beyond the cervix, into the uterus (see Figure 14.8).
Figure 14.8 Artificial insemination of
a cow.
For AI to be successful, it is important that signs of heat are detected and that
insemination takes place at the best time. In cows, oestrus (the period on heat) lasts
12–28 hours. The optimum time is between 5 and 20 hours after the beginning of
oestrus, because ovulation occurs 10 – 16 hours after the end of oestrus.
14.6 Advantages and disadvantages of artificial
insemination
Advantages
Figure 14.9 Semen in a storage straw.
• Farmers are more motivated to keep records.
• There is an improvement or upgrading of the farmer’s stock of animals.
• It removes the risks involved in rearing dangerous male animals, for example,
bulls.
• The costs to the farmer are less than the cost of rearing a male animal to
maturity.
• Female animals do not need to be taken to the breeding station for servicing.
• The spread of venereal diseases is reduced or prevented.
• Young females, such as heifers, are not at risk of physical injury, which can
occur during mating because of the weight of mature bulls.
• Semen from a pedigree male can be used to service hundreds of females.
• Semen from injured males or males that cannot mount females can be used.
• Frozen semen can be stored and used for many years, even after the death of
the male animals.
Disadvantages
ITQ 8
Define the term ‘artificial
insemination’.
ITQ 9
List TWO advantages and TWO
disadvantages of artificial
insemination.
ITQ 10
Describe the contents of the solution
that is added to bull semen.
• The cost of setting up and maintaining the necessary facilities can be
expensive.
• Special equipment and skilled personnel, including trained inseminators, are
required for the process.
• Semen storage and inspection facilities need to be maintained. The frozen
semen has to be monitored regularly to detect loss of viability of the sperm.
• There is the possibility of failure with insemination. Farmers may not respond
quickly enough to the signs of oestrus in the females. Cows may come on heat
‘silently’, which is not detected easily by the farmer but would be identified by
a bull.
One disadvantage of the widespread use of AI in dairy cattle is that concentrating
solely on desirable characteristics could result in a loss of genetic variation. The
techniques of diluting and freezing semen mean that fewer bulls need to be kept
and there is a danger of inbreeding depression.
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Section C: Animal production
14.7 The structure of an egg
vitelline membrane
shell
shell membranes
An egg contains the female gamete, or ovum, of a bird. A hen’s egg is ovoid in
shape, 5–6 cm in length, with one end more pointed than the other. The outer
protective shell is made of calcium carbonate (98%) together with magnesium
and phosphate. It is hard and may vary from white to brown, depending on
the breed and age of the hen. The shell has many pores, which allow gaseous
exchange for the fertilised egg.
The parts of a hen’s egg
chalaza
(twisted
albumen)
albumen
yolk
air space
area that will develop into embryo (germinal disc)
Figure 14.10 The internal structure of a
hen’s egg.
Practical activity:
Make labelled drawings to show
the internal and external structure
of a hen’s egg. Write about the
functions of each labelled part next
to the labels.
The egg has different parts.
• Two shell membranes protect the inner parts. The shell is built on the
outer shell membrane. The inner shell membrane surrounds the albumen
(egg white).
• The albumen is made up of proteins, minerals, some carbohydrates and water.
It provides a developing embryo with some food and a source of water. It
protects the embryo against bacterial infection and also protects the yolk from
mechanical injury. The albumen is of two types: thick and thin. The thin
albumen is found just below the shell and surrounds the yolk.
• The chalazae are coils of twisted fibres made from albumen. They hold the
yolk in place.
• The yolk contains fats (phospholipids) to provide food for the developing
embryo if the egg is fertilised. Its yellow colour is created by pigments. To
some extent, the colour of the yolk is influenced by the diet of the hen. Grass
and maize contain yellow pigments. If they are included in the poultry feed,
the yolks will have a dark yellow colour.
• The germinal disc or blastoderm is a white disc on the uppermost surface of
the yolk. If the egg was fertilised this will develop into the embryo.
• The vitelline membrane surrounds and supports the yolk.
• An air space is situated at the blunt end. It is important for gaseous exchange.
The air space gets bigger the longer the egg is stored because water is lost from
the albumen.
14.8 Egg formation and incubation in poultry
Egg formation
oviduct ▶
Egg formation takes place in the reproductive tract of a hen, which consists of a
single ovary and oviduct (see Table 14.4). The oviduct is a long tube divided into
several sections. Each section has a distinct function.
A hen’s egg consists of an ovum (the egg cell) surrounded by yolk, albumen, the
shell membranes, the shell and the cuticle. Each part of an egg is laid down in a
different section of the oviduct and it takes 24 hours for an egg to pass from the
ovary, through the oviduct to the vent (cloaca).
germinal disc ▶
infundibulum ▶
210
An ovary can contain up to 12 000 ova (egg cells) and it takes around 10 days
for an ovum to mature into a yolk. The yolk contains lipids and proteins, and is
yellow. The ovum is on the surface of the yolk and can be seen as a small white
structure, called the germinal disc. Under the influence of hormones, the ovary
releases mature ova into the top part of the oviduct, called the infundibulum.
The functions of the different parts of the oviduct are described in Table 14.4.
14: Animal genetics, breeding and reproduction
Part of the oviduct
ova
Time spent by ovum
in each location
Infundibulum
infundibulum
Magnum
About 3 hours
Isthmus
About 1 hour
Uterus / shell gland
18 – 20 hours
Vagina
1 – 10 minutes
magnum
isthmus
uterus
rectum
vagina
vent / cloaca
Figure 14.11 The reproductive tract of
a hen.
Vent / cloaca
Functions
Engulfs the yolk and deposits it in the magnum.
If mating has occurred, fertilisation takes place
here.
Albumen is produced here and surrounds the
yolk. Thickened albumen forms the chalazae,
which hold the yolk in a central position.
Two shell membranes are placed around the
egg.
The shell, formed mainly of calcium carbonate,
is deposited on the outer shell membrane.
The egg stays here for a short time only, during
which it is rotated through 180° so that it is laid
large end first.
The completed egg is expelled through this
opening.
Table 14.4 The functions of the parts of the oviduct of a hen.
Incubation
incubation ▶
Incubation is the process of providing the conditions needed to hatch fertile eggs.
It is important because it enables the farmer to obtain new stock (chicks) for the
production of meat, eggs and feathers. It is an important ‘farm-support’ industry,
supplying chicks for farmers to raise as broilers or layers, as well as providing
for the development of new strains of poultry by breeding. Fertile eggs can be
incubated naturally using a broody hen or artificially in an incubator.
Natural incubation
This system is still favoured by small farmers in rural communities. It involves
the use of a broody hen that has just completed a laying cycle. She sits on a
clutch of 10 – 15 eggs in her nest and provides them with warmth needed by the
developing embryos inside the eggs, until they eventually hatch.
Figure 14.12 A hen with a brood of chicks
that have been incubated naturally.
Figure 14.13 A commercial incubator.
The following factors can influence this process.
• Nesting environment: A cool, quiet, well-ventilated and darkened area
encourages the hen to lay and incubate eggs.
• Curvature of the nest: The hen moves her body and feet in a circular manner
to prepare a nest that is bowl-shaped. This shape brings all the eggs close
together so that they are warmed by the body of the hen.
• Clutch size: Normally, the farmer allows the hen to lay and incubate
10 – 15 fertile eggs.
• Temperature: Warmth is essential for the development of the embryos. The
hen’s normal body temperature is 39.4 °C and this provides the warmth
needed. She sits on the eggs most of the time, except for short periods when
she feeds, defecates and exercises.
• Turning the eggs: An egg must be turned to prevent the yolk sticking to the
shell and causing abnormalities or the death of the embryo. The hen uses her
beak and body to turn the eggs, usually at 10-minute intervals.
• Position of the embryo: Despite the angle at which an egg lies, the embryo
usually rises to the top and is close to the warm body of the hen.
The incubation period lasts for 21 days, after which the chicks emerge.
211
Section C: Animal production
Hen farm with artificial incubation
The rearing of broiler birds is a common practice for small-, medium- and large-scale farmers in the Caribbean.
Without the use of artificial incubation, it would be impossible for companies to supply the demand of day-old
chicks to farmers. Companies that produce animal feed also produce the day-old chicks. Each day, thousands of
day-old chicks are produced by artificial incubation and delivered twice a week to farmers across the island.
artificial incubation ▶
Practical activities:
You can learn how to candle an egg
using a torch. You will need to be in
a hatchery to do this.
1. Gently lift an egg from the
incubator. Holding it carefully,
shine a torch onto the shell.
2. Look through the shell from
the opposite side to the torch
and note whether the egg is
fertile, infertile or spoilt.
3. Test 25 eggs, recording the
result each time.
4. Calculate the percentage of
fertile, infertile or spoilt eggs
in the batch you are testing
(do this by multiplying your
results by 4).
Artificial incubation
Artificial incubation is a scientific method to produce small or large numbers
of chicks, in batches, for the farming community. It requires fertile eggs and
specialised equipment called incubators. In the poultry industry, the incubators
may vary in size, shape and complexity, but they all provide the right conditions
for the production of chicks.
Certain conditions are essential for artificial incubation.
• Incubators: These must be cleaned, sanitised and prepared before the eggs are
placed in them. They should be checked to ensure that automatic parts and
systems are working properly. They should have a reliable source of power
(gas, oil or electricity) for the generation of heat, and must provide adequate
space for each egg and chick that emerges (25 cm3 per egg / chick).
• Fertile eggs: These are usually large, with an average weight of 55 g. They
must be checked for cracks and abnormalities. They are wiped clean using
a soft, damp cloth containing a mild disinfectant, and then placed in the
incubating tray with the large ends on top.
• Heat supply: The temperature is controlled by a thermostat and powered by
gas, oil or electricity. The initial temperature should be maintained at 38.5 °C
for weeks 1 and 2, and increased to 39.5 °C in Week 3.
• Humidity: This should be maintained around 60% to prevent rapid loss of
moisture by evaporation through the porous shells of the eggs. This ensures
normal embryo development and reduces mortality.
• Ventilation: The area needs to be well ventilated for the exchange of gases
through the porous eggshells. Oxygen is needed and carbon dioxide must
be removed.
• Turning the eggs: This prevents the yolks from sticking to the shells, and
may be done manually in small, box-type incubators. Mechanical turning is
achieved by automatic devices, which tilt the trays constantly.
Candling
candling ▶
Candling is the process by which eggs are tested for fertility. In this process, a
light is shone through them. It gets its name from when candles were used as the
light source. The process is carried out on artificially incubated eggs between days
9–15 of incubation so that infertile and bad eggs can be removed.
If eggs are fertile, the developing embryo will show up as a dark spot with spiderlike veins. Infertile eggs will be clear except for the shadow of the yolk. Spoilt eggs,
which contain dead embryos, show dark spots caused by bacteria. If these eggs
are left in the incubator they produce hydrogen sulphide gas and will eventually
explode, damaging the other eggs.
212
14: Animal genetics, breeding and reproduction
Revision map
Butterfat
content
of milk
Litter size
in pigs
Carcass
weight
in pigs
Milk
yield
Often show
increased fitness,
known as hybrid
vigour or
heterosis
A hybrid
animal is the result
of mating animals
from two different
breeds
Understanding
how characteristics
are inherited is essential
to animal breeding
programmes
The effect
of the genes on a
particular characteristic is
called heritability. Most
characteristics, such as milk
yield, are determined by
more than one pair
of genes
Candling
determines
whether eggs
are fertile
Egg formation
takes place in the
oviduct of the hen after
an ovum (egg cell) has
been released from
the ovary
Large
numbers of eggs
can be incubated at
one time in a
commercial
incubator
Their
genotype
The
environment in
which they
live
Variation in
the performance
of the animals of
a particular
breed
A breeding
system is the mating of
male and female animals
chosen for their
desirable
characteristics
Keeping
careful records
of animals’
performance
The
identification
of desirable
characteristics
Selection
of suitable
animals for
breeding
The principles
of genetic
improvement
Cross-breeding –
an animal is mated
with another of the same
species but of a different
breed so the genes from
the two breeds
are combined
Types of
breeding
Upgrading –
crossing native, or
local, breeds of farm
animals with breeds
from other regions
of the world
Egg
formation
and incubation
in poultry
Period between
fertilisation
and the birth of
the young
(parturition)
The removal
of semen from a
male farm animal (bull),
used to fertilise very
large numbers of
female animals
(cows)
Favourable genes
of farm animals can be
passed on to large numbers
of offspring, which will
improve the productivity
of the breed
Artificial
insemination
Animal genetics,
breeding and
reproduction
Embryo transfer
is the process of removing
young embryos from the uterus
of a female animal (the donor) and
implanting them into the uterus
of another female animal
(the surrogate) where they
can develop into
offspring
Length
of gestation
varies between
breeds
Gestation
Genetic
engineering
Natural
incubation
Artificial
incubation
Uses
incubators in
which fertile eggs are
kept in the right conditions
of temperature and
humidity until
they hatch
Inbreeding –
mating of two animals
of the same breed. The
animals are closely related
and therefore genetically
similar. Inbreeding can
lead to inbreeding
depression
Ovulation
Terms used
in animal
reproduction
21 days
Broody hen
sits on fertilised
eggs and keeps
them warm until
they hatch
Concern
expressed about the
effect of GMOs on the
environment and on the
health of people
and animals
Some GM
animals but most
research centred
on GM plant
crops
Used to
transfer genes from
one organism to
another
Desired
genes inserted into
the nucleus of a fertilised
ovum; embryo is then
implanted into a
surrogate mother
Occurs
in female
animals
Oestrus
synchronisation
Occurs during
the cycle, during
oestrus or shortly
afterwards
A female
mammal is brought
into heat by
hormones
It is
important
as it can reduce
costs for the
farm
Oestrous
cycle
Results in
female becoming
receptive to male
during oestrus
If mating
occurs, then any ova in
the female reproductive
tract could be fertilised
and develop into
offspring
Parturition
Birth of
the young
Controlled
by the hormones
oxytocin and
relaxin
In rabbits,
the term used is
kindling and in pigs
it is called
farrowing
213
Section C: Animal production
Examination-style questions
Multiple-choice questions
Write down the number of the question followed by the letter of the correct answer.
1.
2.
3.
4.
Which of the following breeding systems is used to develop breeds of livestock especially
for the Caribbean region?
A Cross-breeding
B Upgrading
C Inbreeding
D Back-crossing
In which part of the oviduct does the egg remain for the longest time?
A Infundibulum
B Magnum
C Isthmus
D Uterus
In a commercial incubator, how much space should be allowed for each egg or chick that
emerges?
A 15 cm3
B 20 cm3
C 25 cm3
D 30 cm3
Salts are added to diluted semen before it is frozen and stored in order to:
A nourish the sperm
B prevent infection
C protect against the effects of freezing
D maintain the correct pH.
Short-answer and essay-type questions
5.
6.
List FIVE classes of farm animal that are currently reared locally and regionally.
(a) List the common signs of heat in a cow.
(b) Explain the relationship of the oestrus cycle, signs of heat and pregnancy in
farm animals.
(c) State the importance of the relationships mentioned in question (b) to the farmer.
7. (a) List the essential steps in obtaining semen for artificial insemination.
(b) State the main advantages and disadvantages of artificial insemination.
8. (a) What is the meaning of ‘parturition’?
(b) What assistance should the farm attendant provide to a sow at parturition?
9. (a) Describe the process of egg formation in poultry.
(b) Describe the process of natural incubation.
(c) How does artificial incubation differ from natural incubation?
10. (a) Describe how genetically modified animals can be produced.
(b) Discuss the advantages and disadvantages of the use of genetically modified
organisms in the production of food.
214
Section C: Animal production
15
Animal
products
By the end of this unit you should be able to:
✔ demonstrate proper procedures in slaughtering, dressing and handling
farm animals
✔ determine the dressing percentage of different farm animals
✔ list the principal farm animal products and by-products including those
derived from the offal
✔ demonstrate the practices involved in rearing layer birds and the
production of eggs.
Concept map
Slaughtering
procedures
Broilers
Humane methods
Dressing and packaging
Carcass quality
Dressing percentage
Dressed weight calculation
Relationship between
weight and age
Animal products
Rearing layer birds
and egg production
Animal products
Housing
Eggs
Deep litter systems
Battery systems
Table
Hatching
Eggs
Milk
Clearing
Grading
Homogenisation
Pasteurisation
Sterilisation
Animal
by-products
Offal
Biogas
Honey
Fish
Meat
Abattoir
Vacuum packaging
215
Section C: Animal production
Practical activities:
1. Slaughter and dress some
broilers for market. This activity
could follow on from the
practical activity that involved
raising broilers in Unit 12.
If this is not possible, visit a
local farm or a large poultry
producer to observe broilers
being dressed and prepared for
market.
2. Investigate marketing
strategies for selling broilers,
and using social media
marketing channels and
websites for online marketing
strategies.
3. Visit local stores and
supermarkets to find out how
they sell their chickens.
4. Conduct an open day in
collaboration with other
departments.
15.1 Slaughtering procedures
Slaughter of broilers
The time for slaughtering broilers can be determined by their dressing percentage
and their age. At about seven weeks, a broiler will weigh around 1.8 –2 kg. This
varies slightly with the breed, feeding regime, type of feed used and environmental
conditions. Broiler chicks are fed on starter ration until six weeks old and given
finisher ration for the next few weeks. Broilers have a dressing percentage
between 75% and 80%. The farmer can work out the best live weight that will
give a profitable return on the investment in feed, and decide when to send the
broilers to market. Broilers are usually sent around seven weeks old, but fastergrowing breeds may reach a suitable weight in less time.
If the number of broilers is small, they can be slaughtered by hand. If there are a
larger number of broilers, slaughtering is usually mechanised and a production
line is set up. Whichever method is used, the birds are not given food for six to
eight hours but are allowed water. This is to ensure the gastrointestinal tract is
free of faecal matter. When there is less faecal matter, there are fewer bacteria
present at the processing plant to contaminate other birds.
Using humane methods
The most humane way to slaughter a chicken is to cut the jugular vein in the neck
with a very sharp knife. Blood drains out for two minutes and the bird is then
scalded and plucked to remove feathers. If carried out at home, the bird is caught
and held firmly with its head pointing downwards. It will lose consciousness
quickly once the vein has been cut. Scalding can be carried out by immersing
the bird in a bucket of hot water (60 °C) for one minute. This makes the feathers
easier to remove, which should be done immediately after scalding. On large
poultry farms, birds are suspended, head downwards, from hooks on a moving
line. They are stunned electrically before their necks are cut, either manually or
mechanically.
Dressing and packaging
The carcasses are dressed by removing all the internal organs, the head, the neck
and the feet. After the head and neck have been removed, the internal organs in
the upper part of the body cavity can be loosened.
Figure 15.1 A beef carcass.
216
A cut is made all round the vent to remove the intestine and other internal
organs. A hand can be inserted into the cavity and the organs are loosened and
pulled through the vent opening. The bird is washed thoroughly and then cooled.
The heart is removed and washed to remove any blood. The liver and gizzard
(stomach) are separated from the rest of the intestines and cleaned. After that, the
gall bladder is removed from the liver, and the gizzard is opened to remove any
contents and its lining is removed. The heart, liver, gizzard and neck are referred
to as the giblets and are often sold with the bird. Chicken livers are used to make
pâté and other dishes. Whole birds are packed into polythene bags and sent for
sale or frozen.
15: Animal products
ITQ 1
Which parts of the digestive system
of chickens are saved and cleaned
for use?
carcass quality ▶
The dressed carcasses of farm animals are usually cut into sections, each having a
special name. The cuts have varying shapes and are graded differently for specific
purposes, for example, roasting, grilling, braising or barbecuing. They are graded
and priced to suit the tastes, preferences and price acceptance of consumers.
The carcass quality refers to these characteristics of the carcass.
• Conformation: This is the proportion of meat and fat to bone. It relates to the
meatiness and shape of the carcass.
• Colour: Beef should be bright red. Veal is white or light pink. Pork is greyishpink or darker. Lamb is light to dark pink. Chicken is pinkish white and duck
is reddish.
• Texture: This describes whether the carcass meat is soft, moist and firm or
tough, stringy and dry.
• Fat: This characteristic describes the quantity of fat present in the meat, and
the colour. Pork fat is firm and white. Lamb fat is white, smooth and even.
Beef fat is creamy white. Poultry fat is whitish yellow. The term ‘marbling’ is
used to describe the presence of fat between and around the muscle fibres.
• Palatability: This is the aroma, tenderness, juiciness and flavour of the meat.
15.2 The dressing percentage of farm animals
live weight ▶
dressed weight ▶
dressed carcass weight ▶
Live weight is the weight of an animal before slaughter. Live weight in cattle and
small ruminants is often referred to as the weight ‘on the hoof’. Dressed weight,
also known as dressed carcass weight or slaughter weight, is the weight of the
meat after the animal has been slaughtered and the offal has been removed. (The
offal is those parts of an animal that are used as food but do not consist of skeletal
muscle or meat.)
Dressing percentage (see Table 15.1) refers to the percentage of the live weight
usually obtained as edible carcass (meat) after slaughter. Live weight and carcass
weight are directly related to the dressing percentage of the slaughtered animal.
These weights vary considerably among the different classes of farm animal and
are of economic importance to producers and consumers.
ITQ 2
This is the formula for calculating the dressing percentage.
(a) What is meant by the dressing
percentage and how is it
calculated?
(b) A rabbit has a live weight of
4.6 kg and a dressed weight
of 2.9 kg. What is the dressing
percentage?
(c) A bullock has a live weight of
230 kg. Using Table 15.1, state
both the (i) maximum and (ii)
minimum dressed weight of
the bullock.
Dressed weight (kg) ____
100
Dressing percentage = __________________
​
​ × ​   ​
Live weight (kg)
1
For example, if the live weight is 115 kg and the dressed weight is 85 kg, then the
dressing percentage:
85 kg 100
​   ​= 73.9%
= ​ _______ ​ × ____
115 kg
1
Class of farm animal
Poultry
Rabbits
Goats and sheep
Pigs
Cattle
Dressing percentage
75 – 80
55 – 65
55 – 60
70 – 75
50 – 60
Table 15.1 The dressing percentages of major farm animals.
217
Section C: Animal production
Relationship between weight and age
The relationship between weight and age in farm animals helps the farmer to
decide on the right time to slaughter. Some animals may be slaughtered at the age
of weaning. This is the practice for suckling pigs and calves for veal.
It may be impractical to rear meat animals beyond a certain age because:
• feed costs for the animal increase as it gets older
• as the animal ages, it consumes an increasing quantity of feed but puts on
weight at a much slower rate, so the feed conversion ratio (FCR) drops
significantly
• the quality of the meat is affected, for example, nine-week-old broiler
chickens can be tough.
The weight-to-age relationship also indicates the stage of development in terms
of a balance between bone and muscle. Optimum slaughter weights are based on
research data. They take into account the breed, age, sex and feeding regimes of
the various classes of farm animal.
15.3 Animal products and by-products
Most products from farm animals are used for human nutrition, but some are
processed and used for livestock feed. In addition, a number of by-products have
important economic uses.
Eggs
Figure 15.2 Fresh table eggs.
table eggs ▶
Eggs are used in many ways and are produced worldwide in very large quantities.
They are highly nutritious and contain proteins, fats, vitamins and minerals. In
the Caribbean, layers are used to produce both hatching eggs and table eggs. The
layers may be raised intensively on farms or in open areas (free range) in rural
communities.
There are two types of table eggs (for eating):
• Farm eggs or farm-fresh eggs: These have pale-yellow yolks and are
usually cheaper.
• Common fowl eggs: These have orange yolks, are more popular and more
expensive.
hatching eggs ▶
ITQ 3
What is the difference between eggs
for hatching and table eggs?
218
Hatching eggs are used by poultry farmers. These eggs may be incubated and
then sold as day-old chicks to be raised as layers or broilers, or poultry farmers
may purchase fertile eggs to incubate and then raise the chicks to replenish their
own stock.
Eggs also have by-products.
• Dried egg: This can be whole dried egg, dried egg yolk or dried egg white.
Dried egg can be reconstituted with water and used in cooking.
• Eggshells: Calcium carbonate makes up 95% of an eggshell. The shells can be
ground to a powder and used in animal feed as a source of calcium. Artists
also use eggshell in painting.
15: Animal products
Milk
Practical activity:
Visit a milk processing facility in
your locality. Visit a dairy farmer to
find out what happens to the milk
that is produced. Does the farmer
use the milk to make products on
the farm?
pasteurisation ▶
homogenisation ▶
sterilisation ▶
ITQ 4
Explain what is meant by the
initials UHT.
Milk is important in human nutrition and a lot of milk is consumed in its fresh
form. However, milk is perishable and requires special treatment so that its
freshness, flavour and taste are maintained.
The following major processes are carried out in the treatment of milk.
• Examination: This is done to determine bacterial content, butterfat content,
unusual odours and foreign matter in the milk. Examination is important for
grading milk.
• Removal of foreign matter, such as dirt particles: This is done by spinning the
milk in a machine called a clarifier, which uses centrifugal force to make the
foreign matter move outwards.
• Separation of butterfat: This produces low-fat and skimmed milk. Other lowfat products can then be made using the milk.
• Pasteurisation: This process destroys pathogenic organisms in milk, thus
protecting public health. It prolongs the storage life of milk and maintains the
nutritional value, taste and colour. It is achieved by heating the milk to 63 °C
for 30 minutes or to 72 °C for 15–20 seconds. The milk is then rapidly cooled
to about 3 °C.
• Homogenisation: In this process, butterfat globules are broken up into
minute particles. The milk is heated to 72 °C for 15–20 seconds to pasteurise
it. It is then subjected to high pressure and forced through a valve. Cream
formation on the surface is prevented.
• Sterilisation: Sterilisation is used to produce ultra-high temperature (UHT)
milk. The milk is heated to 140 °C for 3–5 seconds. This destroys all the
micro-organisms in the milk but the taste, colour and nutritional value of the
milk are maintained. This process extends the storage life of milk considerably.
• Packaging: Glass bottles, paper cartons or tetrapacks can be used to package
milk. These containers are sealed automatically and aseptically (free of
harmful micro-organisms). The containers may then be placed in boxes and
stored at cool temperatures.
Packaged milk should be stored in a cool place at 4 °C. For this reason, milk is
transported in refrigerated delivery trucks to supermarkets and consumer outlets.
Milk may be used to make other dairy products, either on the farm or in processing
plants. Those products made on the farm include butter, cottage cheese, ghee,
yoghurt or dahee and ice cream. In addition, powdered and condensed milk
(sweet milk), butter, cheese and ghee are made in processing plants.
Fish
Figure 15.3 Tilapia is a fish that is
farmed in the Caribbean.
ITQ 5
Explain why fish is an important food
source for people.
Fish and shellfish are important food sources for people. Fish and shellfish are
rich sources of protein, vitamin A and vitamin D as well as some substances in
the vitamin B complex (thiamine, riboflavin and niacin). They also contain the
minerals iodine, calcium and phosphorus. Fish is an alternative to meat and it
is more easily digested than many forms of meat. It can be prepared in a variety
of ways, including baked, curried, stewed, fried, grilled and steamed. Some fish
and shellfish, such as sushi and oysters, are eaten raw. Fish can be preserved by
freezing, smoking, salting, drying and canning.
Fish are also used to create a feed supplement for livestock. Fish bones are ground
up and made into bonemeal. Fishmeal is made by drying and grinding fish waste
or unwanted fish. Ground oyster shells are fed to laying hens, to provide them
with calcium for shell formation.
219
Section C: Animal production
Meat
Meat is an important source of protein in the diet. We eat meat from:
• poultry, for example, chickens and ducks
• goats
• sheep (mutton and lamb)
• pigs (pork and bacon)
• cattle (beef)
• rabbits.
Meat production can be affected by climatic and environmental conditions, public
health and safety concerns, praedial larceny and religious beliefs.
There is an increasing demand for meat and meat products that are:
• fresh from the farm
• lean and muscular, with little fat
• organically produced (home-grown animals). These animals are reared
without growth stimulants or chemicals in their feed.
Figure 15.4 Vacuum-packaged pork
sausage.
abattoir ▶
Once the animals have been slaughtered at the appropriate age or weight, the
meat is marketed. Sheep, goats, pigs and cattle are usually slaughtered in an
abattoir or slaughterhouse. Local laws ensure that the facilities are hygienic and
humane and that animals do not suffer undue distress. The animals are handled
gently, provided with fresh water and transported in suitable vehicles.
After slaughter, the carcasses are bled, the hides removed and the internal organs
taken out. The carcasses are then chilled. The meat is inspected at the abattoir
and stamped as fit for human consumption or taken away for disposal by burial
or burning.
Meat is not cooked and eaten immediately after slaughter, but has a period of
‘conditioning’ or ‘ageing’ during which time it develops flavour as the muscles
become tender.
Practical activity:
Visit a meat processing facility to
identify different cuts of meat and
carcass quality. Take photographs of the
different cuts. Create a poster showing
the cuts of meat and information you
have learnt. Alternatively, you could
search for pictures online to help you
create a poster.
vacuum packaging ▶
220
After ageing, the carcasses are cut into the joints and cuts. Examples of these can
be found in Unit 25. Meat is marketed in different forms: it can be bought straight
from a retailer as a large joint or it may be processed further into chops, steaks
and mince. In many supermarkets, the meat is packaged, labelled and priced to
suit the consumer.
Packaging needs to allow the movement of gases but, at the same time, reduce the
loss of water. To achieve this, plastic film controls the atmosphere inside packs. It
is possible to maintain suitable levels of oxygen and carbon dioxide so that meat
is kept fresh and its colour remains attractive. The red of fresh meat is maintained
by the presence of some oxygen within the pack. Packaging ensures that meat is
not handled, is kept clean and is visible to the consumer. The packs are chilled and
will keep in a refrigerator for a few days after purchase.
Vacuum packaging is now used for meat and meat products. The meat joints
are placed in the packaging and a vacuum is applied to reduce the amount of
gas in the space between the meat and its packaging. The atmosphere inside the
pack will contain less oxygen, thus discouraging the activities of aerobic bacteria,
which could cause spoilage. The packaging of cured meats, such as ham and
smoked sausages, does not need to be permeable to oxygen as the pink colour is
developed during the curing process.
15: Animal products
ITQ 6
Apart from the major cuts, other fresh products for human consumption include
steaks (beef), minced meat (beef, pork, lamb), sausages (beef, pork), chops (lamb,
pork) and roasts (beef, pork, lamb). Meat products include ham and bacon (cured
meats from pigs), together with smoked sausages, for example, bologna and
salami.
Explain why meat is left to age
before being sold for consumption.
ITQ 7
Loin
Picnic
ham
Spare
ribs
Bacon
Breast
Flank
Hind
shank
Fore
shank
Hock
Leg
Figure 15.6 Lamb meat cuts.
Head
Neck
in
Back
Brisket
Shank
gh
i
Th
Wing
Chuck
Drumstick
Figure 15.7 Chicken meat cuts.
Ribs
st
de
rlo
Tongue
Br
ea
Te
n
Cheek
Plate
Sirloin
Tenderloin
Short Top sirloin
loin Bottom
sirloin
Oxtail
Round
Head
Tail
Ne
c
Leg or ham
Figure 15.5 Pig meat cuts.
Ribs
Shoulder
Nec
k
Jowl
Neck
Snout
ek
e
Ch
Sirloin
Boston
butt
Tongue
Loin
Back fat
ead
k
late
Clear p
Ear
Head
H
List FOUR fresh meat products that
are not major cuts.
Flank
Shank
Figure 15.8 Beef meat cuts.
Offal and other by-products
offal ▶
ITQ 8
Describe what is meant by offal.
Give ONE example of a recipe that
use offal as the main ingredient.
Offal refers to those parts of an animal that are used as food but do not consist
of skeletal muscle or meat. It is a term used to describe the internal organs of an
animal and includes liver, kidneys, casings of the intestines, tongue and trotters.
Many nutritious dishes can be made using these parts, for example, tripe is
prepared from part of a cow’s stomach and many dishes contain chicken livers.
In addition, a product called black pudding is made from blood. Offal and meat
scraps are made into pet food.
Other parts of farm animals can be put to good use. Skins are made into leather,
bones into bonemeal and hooves and horns into fertiliser. Fat is rendered down
(melted and clarified) and used to make lard and soap.
221
Section C: Animal production
How to build a
simple biodigester
organic waste
and manure
A biogas digester (also known as a biogas plant
or biodigester) is a large tank where biogas
is produced through the decomposition or
breakdown of organic matter through a process
called anaerobic digestion. It is called a digester
because organic material is eaten and digested by
bacteria and a biogas is produced in the process.
gas output
organic fertiliser
biogas
(under
pressure)
ground
surface
slurry
solid
waste
As shown in Figure 15.9, the organic waste and
Figure 15.9 A biodigester.
manure is added to the tank. As bacteria and
microbes digest the waste anaerobically, a slurry is formed. The upper part of the tank allows biogas to form
under pressure. Organic fertiliser is also formed in a side (balancing) tank. All the inlets and outlets
should have covers as these will help to maintain temperature within the digester, which helps it
work more efficiently. The gas also needs an exit pipe and valve, so that the biogas does not
escape before it can be used for heating, cooking or generating fuel for combustion
engines, which can be altered to convert the gas into mechanical energy.
Biogas
biogas ▶
Biogas can be generated using animal manure. The manure is collected and
placed in a large fermentation tank with water. Anaerobic bacteria (bacteria that
do not need oxygen) break down organic matter, releasing methane and carbon
dioxide gases. These gases can be stored and used as a fuel. In some parts of the
world, farmers generate fuel for heating and cooking in this way as an alternative
to using firewood.
15.4 Rearing layer birds and the production
of eggs
Housing for broilers and layers
eaves extended to keep out the rain
wire mesh
block wall
Figure 15.10 A poultry pen.
222
metal roof
Poultry pens should:
• be situated in a well-drained area
• be constructed so that they are about 10 m wide and have a convenient
length
• have a footbath at the entrance for biosecurity (a range of measures that
protect farms against the spread of pests and diseases)
• be oriented lengthwise in an east-west direction to keep out sunshine
• be made of lumber, with an aluminium / zinc roof with eaves that extend
outwards by 1 m to keep out rain
• have a slightly sloping concrete floor for easy cleaning and washing
• have a brick wall 30 – 45 cm high to retain litter in a deep litter system
• be enclosed with wire mesh from the top of the brick wall to the ceiling
• be barricaded with feed bags, especially on the windward side to keep out rain
and cold draughts
• have a doorway 1 m wide to allow a wheelbarrow transporting feed or waste
to move through it
• have sufficient ventilation and suitable lighting.
15: Animal products
Deep litter systems
deep litter system ▶
ITQ 9
Explain how a well-built battery
system can meet the survival needs
of laying poultry.
battery system ▶
This type of system is commonly used for the rearing of broilers and layers.
In a deep litter system, poultry are provided with litter material to a depth of
10 –15 cm on the floor of the pen. Local materials such as bagasse, lawn grass
trimmings, chopped rice straw, dry grass, sawdust and wood shavings are used as
litter. The litter is stirred once or twice a week and kept dry at all times.
When calculating the number of birds, it is usual to allow 4–5 birds per m2 for
broilers and three birds per m2 for layers. In addition, perches are provided for
roosting and the layers have nest boxes for egg-laying.
Battery systems
In a battery system, birds are housed in cages. This system is mainly used for
layers where land is limited.
The cages have these features.
• They are made with sturdy wire.
• They have a trough for food and water on the outside of the cage.
• There is an outward-sloping floor to make egg collection easier.
• There is a removable tray beneath the wire floor for the collection of
droppings.
A cage for a single hen should be at least 36 cm long, 30 cm wide and 36 cm high.
Cages designed to hold three hens should measure 90 cm long, 36 cm wide and
36 cm high. The cages may be stacked in three or more tiers.
Figure 15.11 This battery system is well
designed. The position of the building allows
a breeze to pass through it to keep the hens
cool and comfortable.
ITQ 10
Describe how eggs are cleaned
and explain why this is the best
technique.
Practical activity:
Collect, clean, grade and pack eggs.
Eggs
Eggs break easily so care needs to be taken when handling them. First, the eggs
are collected from the nest boxes and battery cages by lifting each egg carefully
and placing it in an egg basket. Care should be taken to prevent the eggs from
rolling, colliding and cracking. The number collected is recorded each day.
Eggs are then cleaned by wiping them with a clean piece of cloth that has been
moistened in clean water and squeezed to remove the excess. All blemishes
and bloodstains should be removed. It is not advisable to immerse eggs in water
because washing removes the cuticle, opening up pores in the shell. This allows
the entry of bacteria and the loss of water through evaporation.
Grading is done according to colour, size, weight and damage. Eggs can be brownshelled or white-shelled, jumbo, extra large, large, medium, small and cracked.
Grading is necessary for quality control, consumer satisfaction and pricing.
Graded eggs are packed into egg crates, holding 6, 12 or 30 eggs. Each egg is
placed in the crate so that the larger end is always at the top. This avoids putting
pressure on the thin membrane and the air space at the larger end. Crates are
stored in a cool clean room, free from unpleasant odours. The temperature should
be 10 –13 °C.
Eggs are supplied wholesale to supermarkets and dealers for pricing, labelling and
retailing to consumers.
223
Section C: Animal production
Revision map
On a
moving line
By hand
Carcasses are
dressed by removing
the head, feet and
intestines
After slaughter,
birds are scalded
and the feathers
removed
Mechanically
Vitamins
Minerals
Animals
should be
slaughtered
humanely
Age and weight
determine when farm
animals should
be slaughtered
Protein
After
slaughter, carcasses
are left to age to
develop flavour and
tenderness
Poultry
Fats
Egg
nutrients
Layers and
egg production
Slaughtering
procedures
Animal
products
Dressing
Products and
by-products
Dried eggs
for cooking
and the food
industry
By-products
from eggs
Eggshells used
in animal feeds
as a source of
calcium
Pasteurisation
uses heat to kill
pathogenic
micro-organisms
Milk is perishable
and needs treatment
to keep it nutritious
and palatable
Sterilisation
heating to a very high
temperature (UHT milk)
enables milk to keep
for long period
224
Allows the
movement of gases;
prevents the loss
of water
Meat
packaging
Vacuum packing
used to exclude
all air
Milk
by-products
Ice cream
Yoghurt
Cheese
Keeps the
meat fresh;
maintains its
red colour
Butter
Layers
produce hatching
eggs (to produce new
chickens for sale or for
stock) and table eggs
(to be eaten)
Live weight
and dressed weight
relate to the dressing
percentage of the
slaughtered
animal
Offal
is those parts of a
slaughtered animal
that are used for food
but do not consist of
bone or skeletal
muscle
15: Animal products
Examination-style questions
Multiple-choice questions
Write down the number of the question followed by the letter of the correct answer.
1.
2.
3.
4.
5.
Milk is homogenised to:
A retain its flavour
B destroy pathogenic organisms
C remove dust and particles
D break up fat globules.
Milk can be sterilised by heating it to:
A 72 °C for 15 seconds
B 140 °C for 3 seconds
C 140 °C for 15 seconds
D 72 °C for 3 seconds.
Fish is a rich source of:
A iodine
B magnesium
C potassium
D iron.
Brisket is a cut of meat from:
A pigs
B sheep
C cattle
D goats.
An animal with a live weight of 112 kg and a dressing percentage of 70% has a carcass
weight of approximately:
A 75 kg
B 80 kg
C 85 kg
D 90 kg.
Short-answer and essay-type questions
6.
(a) Differentiate between hatching eggs and table eggs.
(b) List and describe the processes involved in handling eggs on the farm in preparation
for marketing to the consumer.
7. (a) Explain the meaning of (i) homogenisation, (ii) pasteurisation and (iii) sterilisation.
(b) Explain why milk, as a perishable product, requires special treatment.
(c) List and describe the processes involved in milk treatment.
8. (a)Explain the meaning and relationship of live weight, dressed weight and dressing
percentage.
(b) Write down the formula, and then calculate the dressing percentage of a pig that had
a live weight of 114 kg and a dressed weight of 82 kg.
9. (a)List TWO criteria that are generally used to determine when to slaughter farm
animals.
(b) Explain why it is uneconomical for a farmer to rear meat animals beyond a
certain age.
10. Describe the processes involved in the slaughter and dressing of broilers.
225
Section D: The business of farming
16
Economic
factors of
production
By the end of this unit you should be able to:
✔
✔
✔
✔
✔
Concept map
Economic factors of production
Relate the factors of
production to agriculture
Land
Relationships
Relationships
Production
Demand
Sharecropping
Loss of agricultural
land
Primary products
Secondary products
Goods
Labour
Luxury goods
Consumable goods
Capital goods
Family
Casual
Services
Capital
Loans
Fixed capital
Working capital
Marketing
Schedule
Curve
Lack of demand
Change in demand
Factors affecting demand
Supply
Schedule
Curve
Law of supply
Consumption
Management
Factors that change supply
Pricing
Entrepreneurship
Concepts
Value chain
Supply chain
226
relate the factors of production to agriculture
explain the concepts of value chain and supply chain
explain the relationships between production, marketing and consumption
relate changes of demand and supply to pricing
explain the law of diminishing returns.
The effect of changes in
supply and demand
Commodity regulation
Elasticity
Price mechanisms
Law of diminishing
returns
Input
Costs
Output
Returns
Total product curve
Average product curve
Marginal product curve
3 stages
16: Economic factors of production
16.1 Factors of production related to
agriculture
mixed farm ▶
Marketing
(driver)
The economy:
Vehicle of change
and development
Production
Consumption
Farming is a business and a farm can be defined as an economic unit engaged in
the production and sale of agricultural produce for maximum profit. A farm may
produce crops or livestock. Sometimes farms produce both crops and livestock (a
mixed farm).
Farms often consist of different sections, with each section focused on the
production of one type of crop or livestock. Each section of a farm is known
as an agricultural enterprise. The farmer manages each enterprise by deciding
how much to produce and how to allocate resources to obtain high yields and
maximum profit. To do this, the farmer needs to have knowledge about the
production process. The farmer also must understand the likely demand for the
commodity and the way in which it needs to be marketed.
(engine)
(fuel)
In any country, the economy is the vehicle of change and development. There are
three major parts of this vehicle: production, consumption and marketing. Each
part carries out specific functions.
Figure 16.1 Economic functions.
Production plays the role of the engine of the economy, marketing has the role of
the driver, and consumption provides the fuel (see Figure 16.1).
labour
land
Factors of
production
capital
management
Figure 16.2 The factors of production.
factors of production ▶
Agricultural production varies according to the amount, quality and effective use
of these essential resources:
• land
• labour
• capital
• management.
These resources are known as the factors of production.
Land
An essential resource is a resource from which a product is derived. In the case of
agricultural production, land is an essential resource (see Figure 16.2).
The Caribbean region is dominated by small island states with many smallholdings
on hilly terrain. Guyana and Belize, on the other hand, have large expanses of flat
land suitable for large-scale agricultural development. Despite land reclamation
initiatives in some Caribbean countries, land as a factor of production is a limited
resource that cannot be created.
sharecropping ▶
Many farmers do not own land and enter into sharecropping arrangements
with their landlords. Sharecropping is a system of agricultural production in
which a landowner allows a tenant to use the land in return for a share of the
crop produced on the land. Land tenure systems were described in Unit 3.
The suitability of the land for agricultural production depends on both climate and
topography. The climate, with its seasonal variations in rainfall and temperature,
affects the types of crops that can be grown. The topography affects the ease of
cultivation and equipment that can be used (see Unit 7).
227
Section D: The business of farming
ITQ 1
Describe TWO major causes of the
loss of prime agricultural land both
locally and regionally.
Loss of agricultural land
Land often rises in value over time and can make large profits for residential
developers who sell the land for housing. Governments also acquire land in prime
agricultural areas for housing schemes.
Over-cultivation and a loss of soil fertility also make less agricultural land
available. If agricultural productivity is to be maintained or increased, land needs
to be managed and used effectively. Therefore, farmers should adopt suitable soil
management techniques, using cultural practices and improved technology to
maintain soil fertility.
Labour
labour ▶
Labour or employees, also called workers, are people involved in practical
work with their hands. In the Caribbean, labour has been a challenging factor of
production in commercial farming, both locally and regionally. Slavery from the
former plantocracy has resulted in a negative attitude towards agricultural labour.
The descendants of slaves left farming to pursue other careers.
family labour ▶
Farmers with smallholdings largely rely on self-labour and family labour (the
work is done by the family). The cost of such labour is not considered as a part
of the general cost of production, as no money is actually paid out for the work
done.
casual labour ▶
Casual labour
Farmers who operate medium-scale and large-scale farms use hired labour on a
permanent basis and casual labour (temporary, paid labour) for specific farm
operations.
Casual labour may be:
• seasonal labour at peak periods for planting, harvesting, fertiliser application
or pest and disease control
• task labour used for specified hours of work and operations, such as getting
forage and milking cows
• contract labour used for infrastructural work, such as the construction of
livestock pens and land preparation.
Most Caribbean states have introduced a minimum wage for agricultural workers,
which has increased their income, but has not attracted many workers into the
private agricultural sector. People would rather work in offices where the wages
and conditions are better.
The intervention of local and regional governments, as well as the International
Labour Organization (ILO), is required to:
• develop a system of wages based on specialised agricultural skills that would
attract workers to the sector
• improve relations between farmers and their workers
• promote the welfare of farm workers and their families, especially in the
private agricultural sector.
228
16: Economic factors of production
Capital
capital ▶
Capital refers to all monetary assets, buildings, machinery, equipment, tools,
materials, tree crops and livestock that are used to produce agricultural goods and
services on a continuing basis.
Capital is needed to finance any manufacturing process, labour to carry out the
tasks, and some management structure needed to coordinate the activities.
depreciation ▶
assets ▶
Each resource has a productive lifespan and a monetary value that decreases with
time due to depreciation. Depreciation is a decrease in value as a result of age
or wear. Farmers need to ensure that regular maintenance is carried out to keep
each resource in a serviceable condition. Collectively, capital resources and land
are referred to as assets and are expressed in monetary terms as wealth.
Loans
If a farmer needs to finance an agricultural enterprise and has no money from
family resources, he or she may try to get a low-interest loan. The farmer may
have to offer capital resources, or assets, as collateral to the lending institution. In
this way, capital enables the farmer to become self-reliant. Further details about
loans and where farmers can acquire them can be found in Unit 3.
fixed capital ▶
working capital ▶
Fixed and working capital
Fixed capital is the amount of capital permanently invested in a business. It
refers to assets that are not used up in the production of a product. It is the capital
that is invested in land, buildings, vehicles and equipment.
Working capital refers to the assets of a business that are used to convert raw
materials into a product. For a farmer, the working capital consists of labour
costs, costs of seed or stock, means of getting the product to market, and the cash
received for goods. The farmer keeps accounts of expenditure on labour, seeds
and hire of equipment and also the receipts for the produce that is sold. The
farmer can then see whether or not there is a profit, which can be invested to
improve the enterprise.
Management
Management focuses on the effective use of resources by the farmer. These
resources include land, labour, materials, finances and time. Good management
can sustain agricultural output and quality, although maximum production at
minimum cost may damage the land.
ITQ 2
List FIVE managerial functions on
a farm.
On small-sized and medium-sized holdings, most farmers act as their own farm
managers. They carry out the functions of planning, organising and directing
the workers and supervising farm operations. On large farms, farm managers
are employed to carry out these tasks. A farm manager may be responsible for
running a single enterprise or have overall responsibility for the day-to-day
operations on the farm.
Management involves situational analysis, decision-making and accepting full
responsibility for the outcomes. It requires people to combine technical knowledge
of agriculture with practical farming skills and business experience. A good farm
manager has a grasp of the factors of production and uses resources efficiently for
profit.
229
Section D: The business of farming
Entrepreneurship
Entrepreneurship is the development of innovative ideas into profitable business.
Caribbean agriculture is ready for entrepreneurs, particularly with the introduction
of technology to small-scale agriculture. More can be found about this in Unit 27.
Practical activity:
Create a table like the one below and make a list of everything on a farm for which a farmer requires capital. Decide whether the
items on your list are fixed capital or working capital. Consider the lifespan of the fixed capital items and write down when they will
probably need to be replaced.
Item
Tractor
Seeds
Fixed capital
Working capital
Replacement?
20 years
–
✓
✓
16.2 Concepts of the value and supply chains
Value chain
value chain ▶
The value chain refers to the process in which a business receives raw materials,
adds value to them through production, manufacturing and other processes to
create a finished product, and then sells the finished product to consumers.
There are five steps in the value chain process. These steps enable a company to
create a product or service with a value that exceeds the cost of providing the
product or service to customers. Maximising the activities in any one of the five
steps allows a company to have a competitive advantage over other businesses.
These are the five steps or activities.
1.
Inbound
logistics
2.
Operations
3.
Outbound
logistics
4.
Marketing
and sales
5.
Service
Receiving,
warehousing,
and inventory
control.
Value-creating
activities that
transform inputs
into products,
such as
assembly and
manufacturing.
Activities required
to get a finished
product to a
customer.
These include
warehousing,
inventory
management,
order fulfillment
and shipping.
Activities
associated with
getting a buyer
to purchase a
product.
Activities that
maintain and
enhance a
product’s value,
such as
customer
support and
warranty
service.
Figure 16.3 The five steps in a value chain.
230
16: Economic factors of production
Supply chain
supply chain ▶
A supply chain is the network of all the individuals, organisations, resources,
activities and technologies involved in the creation and sale of a product. Every
step in the process – including creating a good or service, manufacturing it,
transporting it to a place of sale and selling it – is part of a company’s supply chain.
While farmers are at the beginning of the supply chain, it needs to be remembered
that the prices of agricultural products for the consumer is also dependent on the
costs incurred along the rest of the supply chain network.
A supply chain includes all the parties involved in fulfilling a customer request to
the customer’s satisfaction, whereas a value chain is a set of interrelated activities
a company uses to create a competitive advantage.
16.3 The relationship between production,
marketing and consumption
Production
production ▶
Production is a planned economic activity that incorporates several inputs. It
focuses on the manufacture of goods and the provision of services. The aim of
production is to satisfy what people want (see Figure 16.4). As the volume of
production increases, wealth is created and this promotes the economic welfare
of the population. The satisfaction of people’s wants improves their standard of
living.
Production
• a process
• an economic activity
Consists of:
• primary production
• secondary production
Focus
Commodities / Goods
• capital goods, e.g. farm tractor
• consumable goods, e.g. foodstuffs
• luxury goods, e.g. big screen TV
Services
• commercial, e.g. agri-chemicals
• technical, e.g. extension officer
• professional, e.g. veterinarian
Aims / objectives
• to satisfy people’s wants
• to promote the economic welfare of people
• to improve people’s standard of living
• to create individual and national wealth
Figure 16.4 The concept of production.
primary production ▶
primary products ▶
Figure 16.5 Pineapple – an example of primary
production.
Types of production
There are two types of production: primary and secondary. Primary production
refers to goods or raw materials that are produced initially, for example, pineapple
or sugar cane. Some of these goods may be consumed as primary products.
231
Section D: The business of farming
secondary production ▶
secondary products ▶
capital goods ▶
consumable goods ▶
luxury goods ▶
ITQ 3
Explain the difference between
primary production and secondary
production, giving examples.
Alternatively, primary products may undergo secondary production, which
involves processing the raw products into secondary products. For example,
pineapple may be processed into jam and juice, and sugar cane can be processed
to make sugar, molasses, bagasse and rum.
Goods
Different kinds of goods are derived from production. Capital goods are items
such as a tractor or dairy herd, which are used in several production cycles. There
is always a quantity of goods that exist on a farm; this is called the capital. Capital
goods are different from financial capital. Consumable goods, such as food,
are goods that are essential for living. Luxury goods, for example, a flat-screen
television, are not needed for living, but many people want them for enjoyment
and social status.
Services
Services can be grouped into:
• commercial services, such as those provided by agri-supply stores and
livestock depots
• technical services, such as those provided by extension officers and agriteachers
• professional services, such as those provided by agricultural consultants and
veterinarians.
Marketing
marketing ▶
Marketing is the link between production and consumption. It incorporates
several business activities in a coordinated way to promote the flow of goods and
services from the point of production to the end point where the consumers can
buy the goods and services.
middlemen ▶
Middlemen operate between the producers and consumers. They are agents,
brokers, wholesalers (merchants), processors and retailers (vendors).
The merchant wholesalers purchase and collect products together at a central
point for distribution to processors and retailers. Often they do this by using the
services of commission agents and brokers, who are also acting as salespeople.
Huge sums of money are spent on advertising to persuade consumers to buy new
products.
Marketing functions (see Table 16.1) depend on the nature of the products, the
quantity produced and the characteristics of the market.
Main function
Merchandising
Includes
Buying, Pricing, Selling
Handling
Transportation, Grading, Assembling, Storage
Processing
Manufacturing, Packaging, Labelling
Supporting
Standardisation, Financing, Risk-bearing (insurance),
Knowledge about the market (market intelligence)
Table 16.1 Marketing functions.
232
Activities involved
The activities focus on trading, product promotion and changing the
ownership of goods.
Attention is paid to the physical activities that enable processing and
easy distribution to retailers and consumers.
The activities change the form of the product, add value and increase
the shelf-life. In addition, the activities aim to satisfy consumers’
tastes and preferences.
These activities are ‘facilitating functions’, which means that they
enable all the other functions to be carried out smoothly.
16: Economic factors of production
Consumption
consumption ▶
consumers ▶
Consumption is an economic, consumer-centred activity. It involves the purchase
and use of goods and services by clients and customers, known as consumers.
Consumption normally comes after production and marketing, and is the fuel
that keeps the economic engine of production running (see Figure 16.6).
• income level of consumers
• satisfaction of consumer needs
• product substitutes (are there other
products that could be used instead?)
• customers
• clients
• an economic consumer-centred activity and process
• an activity that fuels the engine of production
Factors influencing consumption
Consumers
Consumption: what is it?
Decision-making
• end users of
the product
• the purchase and utilisation of goods and services
• the end product of production and marketing
• religious reasons
• health concerns
• aesthetic features
(what the product looks like)
Figure 16.6 The concept of consumption.
ITQ 4
State FOUR factors that contribute
to consumption decision-making
by consumers.
Consumption patterns vary. Here is a list of some of the factors that affect the
decisions that consumers make.
• Income level: Consumers want to obtain goods and services at the lowest cost.
They purchase and use those goods and services that they can afford.
• Satisfaction of needs: Consumers choose goods and services that satisfy their
tastes and convenience. With respect to food, consumers buy products that
are easy to prepare and use, and that meet the consumers’ nutritional and
health needs.
• Religious reasons: Some consumers do not buy certain foods, for example,
pork and beef, because of religious beliefs.
• Health concerns: More consumers are becoming health-conscious and avoid
buying foods that contain high amounts of cholesterol and saturated fats.
• Aesthetic features: Product features (design, presentation, colour, taste and
general appearance) may appeal to consumers, increasing the consumption of
those products.
• Product substitutes: Knowledge of product substitutes and their availability
might enable some consumers to make compromises and choose alternative
goods and services.
16.4 Demand, supply and price relationships
Sellers price their goods at a specific price or within a price range to sell their
stock. The sellers hope to make a profit, which will enable them to continue their
businesses and perhaps expand them. If the price of a good is not controlled by
the government, the seller is free to fix a price based on market intelligence, the
business location and the total cost involved in buying and transporting the good
to the place of business.
ITQ 5
List TWO factors that are considered
by sellers when fixing the price of
a commodity.
The willingness of the consumer to buy a good depends on the price as well as the
supply. If the price is too high, the demand will be low and sales will be poor. If
the price is too low, demand will be high and the seller will be able to sell all the
goods, but the profit may be small and this could affect the business.
Commodities have an optimum (best) price. This is the price that consumers are
willing to pay and that enables the seller to sell all his or her goods at a profit.
233
Section D: The business of farming
This optimum price requires sellers to know how strong the consumer demand is
and also be able to guarantee regular supplies.
Demand
demand ▶
demand schedule ▶
demand prices ▶
Demand is the quantity of a product that consumers are willing to buy at a
certain price at a particular time. Demand is directly related to price. If the price
is high, the demand will be low. A decrease in price will lead to an increase in
demand.
Demand schedule
The demand schedule for a product is the sum of all the individual consumers’
demands, tabulated to show the quantity of the product demanded at various
prices. The demand schedule is also known as the market demand schedule and
the prices are called demand prices.
Table 16.2 is an example of a market demand schedule for cabbages. The
information in the table can also be shown graphically (see Figure 16.7).
7
Quantity of cabbage
demanded (kg)
200
300
400
600
800
1 200
1 500
Table 16.2 A market demand schedule
for cabbage.
demand curve ▶
6
Price per kg (US$)
Price per kg
(US$)
6.50
6.00
5.50
5.00
4.50
4.00
3.00
5
4
3
2
1
0
200
300
400
600
800
1 500
Figure 16.7 A demand curve for the cabbage data shown in Table 16.2.
In Figure 16.8, the curve DD shows the relationship between price and quantity
bought. It is not necessary to have actual prices and quantities marked on the
axes. You can see that price increases on the y-axis and quantity increases on the
x-axis. The typical demand curve DD slopes downward from left to right. The
curve shows that, when the price is high the quantity demanded is low and, as
the price comes down, the quantity demanded goes up.
D
Price
Y
D
0
Quantity
Figure 16.8 A typical demand curve.
234
1 200
Quantity of cabbage purchased (kg)
X
16: Economic factors of production
Demand and supply of Jamaican Blue Mountain coffee
Jamaican Blue Mountain Coffee is a special variety of coffee that is grown in the Blue
Mountains region, which has the best climate and topographical features needed
to produce coffee with a rich aroma and sweet taste. The volume of production is
limited: only about 8 000 hectares can be grown. Because the volume of production
is limited, it costs about 1 800 yen (US$ 17.55) for 100 grams. This price is about three
to four times more than the price of common coffee varieties. Japan consumes about
80% of the Blue Mountain output, making it the biggest market for the Jamaican
coffee. The popularity probably started in the 1950s, when a booming cafe industry
actively incorporated it into menus. “Japan is the only country that puts such a
premium on Blue Mountain coffee,” said an executive at a leading coffee company.
Production of Jamaican coffee, the only source of the Blue Mountain variety, has
dropped to a fifth of its 2007 peak. The Jamaican coffee plantations were severely
affected by Hurricane Sandy in 2012, which damaged many trees. A disease and a
plague of beetles destroyed the country’s coffee plantations even more, and farmers
are still struggling to recover.
As the supply of Jamaica’s Blue Mountain coffee drops, Japanese distributors are being
forced to cope with the shortage by raising prices or halting sales of the Caribbean
variety that is so popular throughout Japan. The Japanese distributor, Ueshima Coffee,
raised the prices of seven products that use the beans by about 40%, even though the
largest Japanese distributor has its own plantation in Jamaica. Its bean purchasing
has fallen by more than half when compared with 2007.
Figure 16.9 Jamaican Blue Mountain
coffee beans.
The ‘law of demand’
‘law of demand’ ▶
Y
D1
D
Change in demand
In Figure 16.10, demand curve DD shows a relationship between price and
demand at a point in time. Demand curve D1D1 shows the demand curve at a
later point in time and demand curve D2D2 shows the demand curve at an even
later point in time. Generally, a change in demand results in a new demand curve,
which represents the new conditions of demand and time.
D2
Price
P
D2
D
D1
0
Q1
Q
Q2
Quantity
Figure 16.10 Changes in the demand
curve.
ITQ 6
Explain the relationship between
the demand and the price of a
commodity.
The first law of supply and demand is also called the ‘law of demand’. It states
that the lower the price is, the greater the quantity demanded is.
X
In Figure 16.10, the original state of demand is represented by curve DD. Curve
DD shows that, at price P, the quantity demanded is Q. Curve D1D1 represents a
change in demand. At the same price of P, the quantity now demanded is Q1. This
quantity is smaller than the original quantity. Curve D2D2 shows another change
in demand. Now, at the same price of P, a larger quantity, Q2, is demanded.
Factors that change demand
Some of the factors bringing about a change in demand are:
• change in tastes and preferences
• change in income
• replacement of old products with new ones (technical innovations)
• change in the prices of other commodities
• change in the population
• change in future trade expectations
• change in taxes and duties
• change in product advertising.
235
Section D: The business of farming
Supply
supply ▶
Supply is the quantity of a commodity that is placed in the market at a particular
time and at a particular price. This is not the entire stock; it is only the amount
that is placed in the market at a particular price. As with demand, the supply of
a product is directly related to the price of that product. Sellers release a larger
amount into the market when the price goes up.
Supply schedule
The supply schedule for a commodity is the total of all the amounts of the
individual sellers, tabulated to show the quantity offered for sale at different
prices. This is also known as the market supply schedule and the prices in the
schedule are called supply prices.
supply schedule ▶
supply prices ▶
Table 16.3 is an example of a supply schedule for cabbages. The information in the
table can also be shown as a supply curve (see Figure 16.11).
Quantity of cabbage
supplied (kg)
200
400
500
600
800
1 000
1 100
8
7
Price per kg (U$)
Price per kg
(US$)
3.00
4.00
4.50
5.00
5.50
6.50
7.00
6
5
4
3
2
1
0
Table 16.3 A supply schedule for
cabbage.
200
400
500
600
800
1 000
1 100
Quantity of cabbage supplied (kg)
1 200
Figure 16.11 A supply curve for the cabbage data in Table 16.3.
Figure 16.12 shows a typical supply curve. This curve shows that, as price goes up
from P1 to P2, the quantity supplied goes up from Q1 to Q2. The curve SS slopes
upwards from left to right.
‘law of supply’ ▶
Y
The second law of supply and demand, also called the ‘law of supply’, states that
the higher the price is, the greater the quantity supplied is.
S
Factors that change supply
These factors cause a change in supply:
• a high consumption of its own product by the producer (less product
is supplied to the market)
• changes in the cost of production
• changes in production techniques
• changes in the weather
• taxation of commodities
• changes in future expectations.
Price
P2
P1
S
0
Q1
Quantity
Figure 16.12 A typical supply curve.
236
Q2
X
16: Economic factors of production
Pricing
equilibrium price ▶
equilibrium point ▶
Y
S
Equilibrium point
Price
D
Commodity prices in a perfect market are determined by the interaction of the
market forces of supply and demand. The price of the product is determined
by the demand in relation to the conditions of the supply at a particular time.
At some point, these two forces are brought into balance (or equilibrium). The
equilibrium price is the price at which demand and supply are equal.
Equilibrium point is where the demand curve DD intersects with the supply
curve SS (see Figure 16.13). Prices set above the equilibrium price will lead to
supply exceeding demand and sellers having a large number of unsold products.
Prices set lower than the equilibrium price will cause demand to exceed supply
and lead to a shortage of the product.
P
0
The effect of changes in demand and supply
D
S
Q
Quantity
X
Figure 16.13 The equilibrium price.
commodity regulation ▶
elasticity ▶
ITQ 7
Describe how the price of a product is
determined in a perfect market.
• An increase in demand tends to increase price and increase supply.
• A decrease in demand has the opposite effect, resulting in a lowering of price
and the quantity supplied.
• An increase in supply tends to lower price and increase demand.
• A decrease in supply will increase price and reduce the quantity demanded.
Major commodities such as sugar cane, cocoa and coffee are exported and are
therefore affected by overseas factors that cause price changes. For these products,
the government sets policies to regulate the supply, demand and pricing nationally
(commodity regulation), as unpredictable price fluctuations based on foreign
markets can destabilise the economy.
Elasticity measures how responsive the market forces of supply and demand
are to changes in price. It also enables the government to set up appropriate
policies to regulate the economy. Government policy around price controls can
set maximum and minimum prices for certain goods. This can protect farmer
incomes and prevent smaller local suppliers from being squeezed out of the
marketplace. Government policy also allows for buffer stocks, where prices are
kept within a certain band, as well as limiting price increases where there is little
competition for a certain product. In the Caribbean, these government policies
are related to elasticity as most agricultural products are produced by small-scale
farmers on low incomes, who would be impacted the most by price changes.
Practical activity:
Online research
Go online and research Caribbean commodities. Expand your research to include global commodities. Record your results in a table.
Two have been completed for you.
See whether you can explain why some types of commodity are not found in the Caribbean.
Commodities
Caribbean
Sugar cane
Global
Gold
237
Section D: The business of farming
Price mechanisms
price mechanism ▶
Practical activity:
Practise plotting demand and
supply curves from data that will be
supplied by your teacher.
A price mechanism matches up buyers and sellers. This stimulates demand for
factors of production and for an increased supply of commodities. The demand
of consumers, or consumption, encourages producers to expand their business.
Demand, supply and price are dependent on one another and the equilibrium
price equates demand with supply.
The government may put price controls on certain commodities. Maximum prices
may be fixed for certain products to protect consumers, especially poorer members
of the community. Minimum fixed prices may be set to protect agricultural
producers against a fall in income due to a bumper harvest.
The purpose of raising prices by taxation is to reduce consumption of commodities
that are thought to be harmful to the economy. This can be done to reduce the
loss of foreign exchange caused by the importation of goods. Subsidies may be
imposed on certain foodstuffs to keep the cost of living down or to encourage
domestic production (production within the country).
16.5 The ‘law of diminishing returns’
If a broiler operation with four members of staff, two debeaking machines and two
defeathering machines increased its number of employees, but did not increase
the number of machines it owned, the extra staff would have an effect on the
workload but little effect on the output, despite the additional cost of their wages.
This is an example of the ‘law of diminishing returns’. To understand how this law
works, we need to understand the terms used.
Input
input ▶
Input is something that is ‘put into’ a production system for a particular purpose
and that contributes to the end result.
fixed inputs ▶
variable inputs ▶
In a farming enterprise, there are fixed inputs (inputs that do not change) such
as land, machinery and farm buildings. There are also variable inputs (inputs
that may change), such as labour, fuel, planting materials, fertilisers and pesticides.
Output
output ▶
yield ▶
The output is the quantity of product created in a production process. It can also
be called the yield or the return. The output may be expressed in metric tonnes
(sugar cane), kilograms (sweet potatoes) or number of products, for example,
lettuce or eggs. In economics, output is always measured in units. One unit could
be 100 kg of sweet potatoes or 1 000 table eggs.
The production of further units of output would require a greater amount of
inputs, which would increase the total cost to the farmer. Since most farmers
operate with limited resources, they are limited in the maximum number of units
of output they can produce. For example, a farmer would need to cultivate extra
land, employ more labour and spend more on fertilisers if extra units of sweet
potatoes were to be produced.
238
16: Economic factors of production
Returns
returns ▶
Farmers put inputs into agricultural enterprises with the aim of making a profit.
The yields of the crop or the profits made are called the returns.
In producing one hectare of sweet potatoes, for example, a farmer may gradually
increase the units of fertiliser used (input) and find that the yield (output) has
also increased. Table 16.4 shows the effect on output that the increase in units of
fertiliser had. This information is also shown Figure 16.14. Notice that the total
output does not increase by the same amount each time.
4 000
3 500
Units of fertiliser
used (t)
0
0.5
1
1.5
2
2.5
3
3.5
4
Total output (kg)
800
1 500
3 000
3 300
3 500
3 600
3 650
3 680
3 700
Table 16.4 The effect on output of
an increase in units of fertiliser used.
marginal output ▶
Marginal output (kg)
3 000
2 500
2 000
1 500
1 000
500
0
0.5
1
1.5
2
2.5
3
3.5
4
Unit of fertiliser (tonnes)
Figure 16.14 A graph showing the yield (total output) of sweet potatoes in kg against the
units of fertiliser (input).
Marginal output (marginal yield or marginal product) is the increase in total
output that results from increasing the variable input by one unit. The unit
increase used in Table 16.5 is 0.5 tonne.
1 500
Total output
(kg)
Marginal
output (kg)
800
1 500
3 000
3 300
3 500
3 600
3 650
3 680
3 700
0
700
1 500
300
200
100
50
30
20
Table 16.5 Marginal yield.
Marginal output (kg)
1 200
Units of
fertiliser
used (t)
0
0.5
1
1.5
2
2.5
3
3.5
4
900
600
300
0
0
0.5
1
1.5
2
2.5
3
3.5
4
Unit of fertiliser (tonnes)
Figure 16.15 A graph showing the increase in yield of sweet potatoes (marginal output) in
kg by adding units of fertiliser (input) in tonnes.
239
Section D: The business of farming
In a production process where units of input are being added, there comes a point
where adding a further unit of input will result in a smaller increase in output
than when the previous unit was added. In the example, this happens after the
second unit.
The increase in output by adding the second unit of fertiliser was 1 500 kg but
adding the third unit increased the output by only 300 kg.
Up to two units, the effect of the fertiliser increases with each unit added
(increasing returns). After two units of fertiliser, the effect of adding a unit of
fertiliser becomes less and less (decreasing returns).
The law of diminishing returns
Decreasing returns does not mean that the total output goes down. It means that,
with each additional unit of input, the total output increases at a declining rate.
This is the law of diminishing returns.
The ‘law of diminishing returns’ is also known as the ‘law of diminishing marginal
returns’ and also as the ‘law of marginal proportions’.
Costs
The farmer has to think about his or her profit, and not just the yield. Fertiliser is
an expensive input. Extra yield also needs more labour to harvest and transport to
market. If the farmer increases prices to cover these costs, the crop might not sell.
The farmer needs to analyse the costs as well as the law of diminishing returns.
costs ▶
Farmers have to buy farm inputs in order to convert them into products (outputs).
Costs are the expenses involved in any transaction.
Costs in broiler production
Fixed
Land
Buildings
Equipment
Vehicle
Variable
Broiler chicks
Feed
Medication
Labour
Fuel
Maintenance: machinery and equipment
Table 16.6 Fixed and variable costs in broiler production.
fixed costs, variable costs ▶
Costs that do not change, such as land rental, machinery and buildings, are referred
to as fixed costs. Variable costs are those costs that change with the level of
production. These costs include the cost of fuel, feed, fertilisers and pesticides. If
a farmer decides to increase the number of broiler chicks, then more feed will be
needed.
The costs associated with output are:
• fixed costs (FC)
• variable costs (VC)
• total cost (TC)
• average cost (AC)
• marginal cost (MC).
240
16: Economic factors of production
total cost ▶
average cost ▶
marginal cost ▶
ITQ 8
Using Table 16.7, show how the total
cost, average cost and marginal cost
for FOUR units of output have been
calculated.
ITQ 9
Look at Row 5 in Table 16.7. Check
each TC, AC and MC. How did you
calculate each figure?
At any level of output:
• total cost = fixed cost + variable cost
total cost
​
• average cost = ​ ________________________
number of units of output
• marginal cost is the increase in total cost that is derived from the last unit of
commodity that is produced.
Units of
output
1
2
3
4
5
Fixed cost
(US$)
30
30
30
30
30
Variable cost Total cost
(US$)
(US$)
70
100
160
190
240
270
310
340
370
400
Average cost Marginal
(US$)
cost (US$)
100
100
95
90
90
80
85
70
80
60
Table 16.7 Product : cost relationships.
Using total cost, average cost and marginal cost together
Total cost, actual cost and marginal cost interact. Table 16.8 shows the effect, in
cost terms, of fertiliser on a corn crop. For a fixed input of land (one hectare),
column 3 shows the effect of changing the fertiliser dosage. (The amount of
fertiliser used is a variable input.) This column shows the total product (also called
total output) of corn. From this information, the marginal product (also called
marginal output) and the average product (also called average output) can be
calculated.
Figure 16.16 A field of corn.
ITQ 10
In the example of Table 16.8, how
many units of fertiliser should the
farmer apply to get the maximum
marginal product from the crop?
Fixed
input:
Land (ha)
Variable input:
Fertiliser
(in 50 kg units)
1
1
1
1
1
1
1
1
1
1
1
1
1
2
3
4
5
6
7
8
9
10
11
12
Total product
(TP):
Corn (in
100 kg units)
3
7
22
35
43
45
46
45
43
42
42
42
Marginal
product (MP):
Corn (in 100 kg
units)
–
4
15
13
8
2
1
–1
–2
–1
0
0
Average
product (AP):
Corn (in
100 kg units)
3.0
3.5
7.3
8.8
8.6
7.5
6.6
5.6
4.8
4.2
3.8
3.5
Notes
Maximum MP
Maximum AP
Maximum TP
Negative MP
MP = zero
Table 16.8 The effect of fertiliser input on a corn crop.
ITQ 11
In the paragraph after Table 16.8,
why is the marginal output quoted
as being 200 kg when the table
shows a value of 2?
total product curve ▶
Remember marginal output (marginal yield or marginal product) is the increase
in total output that results from increasing the variable input by one unit. For
example, if six units of fertiliser are applied, the total output is 4 500 kg of corn,
the average output is 750 kg of corn and the marginal output is 200 kg of corn.
Figure 16.17 shows the relationship between the variable input and the total
output. This is called the total product curve. It rises quickly, levels off and
then starts to decline. The output increases rapidly, then slows until it reaches a
maximum level and then declines. The maximum rate is reached at point D. This
occurs when the marginal product curve reaches 0. The declining rate of increase
starts at point A, when the marginal product is at its maximum.
241
Section D: The business of farming
stage 1
stage 2
stage 3
D
OUTPUT: corn (kg)
total product curve
A
B
0
C
E
INPUT: fertiliser (kg)
average product curve
marginal product curve
Figure 16.17 Diminishing returns: total, marginal and average product.
average product curve ▶
The average product curve is determined from the total product divided by the
number of units of variable input. The shape of the curve depends on the shape
of the total product curve. The maximum is reached at point C. At this point, the
average product is equal to the marginal product.
marginal product curve ▶
The marginal product curve increases rapidly in the beginning, reaches a
maximum and then declines. The decline may be rapid or slow. When the average
product is at a maximum (point C), the marginal product is equal to the average
product. The marginal product becomes 0 (point E) when the total product curve
is at a maximum (point D).
ITQ 12
Explain why stage 3 is described as
the inefficient stage of production.
Practical activity:
Work in groups. Each group should
research a national agricultural
enterprise.
The research should be presented
to the class, followed by a class
vote on which enterprise is the
most successful, or has the most
impressive achievements.
The class is to decide which
factors are most important to
overall success for an agricultural
enterprise.
242
The three stages
Look at Figure 16.17. In stage 1, the total product is increasing rapidly. The end
of stage 1 is the point where average product equals marginal product. In stage 2,
both average product and marginal product are declining, although total product
is still increasing, but at a slower rate than before. Stage 3 represents the inefficient
stage of production because total product and average product decrease and
marginal product shows negative values. It is costly to increase the variable input
beyond the point where the total product is at its maximum.
Agriculture and the ‘law of diminishing returns’
The ‘law of diminishing returns’ is important to farmers and horticulturalists.
Producers need to remember that there is a limit to how much they can increase
growth and development in crops and animals. Eventually the point is reached
when the returns start to diminish.
As an example, when producing broilers, the returns begin to diminish after eight
weeks when the broilers have reached an average weight of 2 kg. From this time
onwards, the birds eat a large quantity of feed but the rate of increase in their
body weight declines. It is a waste of feed (and money) if chickens are kept until
they reach 3.5 kg.
In the case of crops, there may be wastage of fertilisers, organic manure, pesticides
and labour if variable inputs do not result in the maximum marginal product.
These extra inputs could be used more profitably to produce other short-term
crops.
16: Economic factors of production
Revision map
Larger farms
employ labour, which
may be seasonal to cope
with planting and
harvesting
Small farms
are managed by
farmers and rely on
self-labour and
family labour
Labour is a
major factor in any
agricultural
enterprise
Farm
buildings
Farm
managers may be
responsible for specific
enterprises on large
farms
Capital needed
for buying resources
such as land, tractors
and buildings
Farmers may
obtain loans from
institutions such as
banks and credit
unions
Land may
be owned, rented
or leased. Suitability
of land depends on
topography and
climate
Relate the
factors of
production to
agriculture
Changes in
supply and demand
can alter the price of
a commodity. Demand,
supply and price are
dependent on one
another
Returns
are the yield of
the crop or the
profit made
Costs are
the expenses
involved in any
enterprise
Relationships
among production,
marketing and
consumption
Demand is the
quantity of a product
that consumers are willing
to buy at a certain price
at a particular
time
The higher the
price, the greater
the quantity
that will be
supplied
Increasing the
number of outputs
means that the number
of inputs has to
be increased
If an input
(such as the quantity
of fertiliser used) is
increased, then the output
increases progressively
up to a maximum
point
Consumption
is influenced by
income level, needs
and health
concerns
The law of
diminishing returns
is of relevance to farmers
as it helps them to avoid
wasting valuable resources
on inputs which do not
increase profits
Marketing is
the link between
production and consumption.
It promotes the flow of goods
and services from the
producer to the
consumer
Primary
production is the
production of goods
or raw materials
that may be
consumed
The equilibrium
price is the price
at which supply
and demand
are equal
The pricing of
commodities depends
on the interaction
of supply and
demand
Fertilisers
After the
maximum has been
reached, addition of extra
units of fertiliser results in a
steady decline. This declining
rate of increase is called
a diminishing
return
Law of
diminishing
returns
The successive
increase in total
output for each additional
unit of input is called
the marginal
product
Seeds
Variable
inputs change with
the level of
production
Output is
the quantity of product
that is produced, it is also
called yield or return and is
measured in units,
e.g. tonnes, kg.
Economic
factors
of production
Supply and
demand
relationships
Labour
Fixed inputs
are fixed costs so
do not change
Inputs are
factors or resources
that are used to
achieve an
outcome
Supply is
the quantity of a
commodity placed on
the market at a
particular time for a
certain price
The lower the
price, the greater
the quantity
that will be
demanded
Land
Machinery
Secondary
production is the
processing of goods
and raw primary
products
Consumption
involves the purchase
and use of goods
and services by
consumers
Production
focuses on the
manufacture of a
wide range of goods
and the provision
of services
It is the fuel
that keeps the
engine of production
going
243
Section D: The business of farming
Examination-style questions
Multiple-choice questions
Write down the number of the question followed by the letter of the correct answer.
1.
2.
3.
4.
5.
6.
Which of the following is an example of secondary production?
A Pineapples
B Sweetcorn
C Sugar
D Eggs
Which of the following marketing functions deals with fixing the price of products?
A Merchandising
B Handling
C Processing
D Supporting
Contract labour is most likely to be used by a farmer for:
A daily milking of cows
B land preparation
C fertiliser application
D harvesting a crop.
Working capital consists of:
A farm buildings
B equipment costs
C rent
D labour costs.
Which of the following is a cost that varies with the level of production?
A Machinery
B Buildings
C Fuel
D Land
The successive increase in total output for each additional unit of input is called the:
A marginal product
B increasing return
C marginal cost
D increasing product.
Short-answer and essay-type questions
7.
(a)
(b)
(a)
(b)
Distinguish between casual labour and permanent labour.
What factors contribute to the farm labour problems in most Caribbean countries?
8.
State the importance of management as it applies to agriculture.
Discuss TWO management practices that farmers should adopt to achieve maximum
profitability from their land.
9. (a)Production is an economic activity or function. What are the other two economic
activities?
(b) Explain the meaning of production as it relates to the national economy.
(c) Differentiate between primary production and secondary production, giving examples
of each.
10. (a)Explain the factors that are considered by sellers in determining the selling price of a
commodity.
(b) Discuss the relationship between the price of an agricultural product and consumers’
willingness to purchase that product.
11. (a) In a perfect market, how is the pricing of commodities determined?
(b) Using a labelled diagram, explain the meaning of equilibrium price.
(c) Briefly discuss the ‘price, supply and demand relationship’.
12. (a) Describe the difference between price control and subsidies.
(b) Explain why price control measures are sometimes used by governments.
244
Section D: The business of farming
17
Farm financing
and support
services
By the end of this unit you should be able to:
✔ outline how capital can be obtained from established sources
✔ discuss the roles and functions of agricultural cooperatives
✔ discuss the incentives that are available to farmers.
Concept map
Obtaining capital
Fixed capital
Working capital
Sources of capital
Applying for a loan
Credit-worthiness
Farm proposal
Budget estimate
Farm records
Credit supervision
Farm financing and support services
Cooperatives
Risk and uncertainty
Concept
Benefits
Types
Incentives
Price supports
Subsidies
Perform different functions
Grouped by links to other organisations
Management
Problems
245
Section D: The business of farming
17.1 Obtaining capital
What is capital?
capital ▶
For the economist, capital is a factor of production used in combination with
land, labour and management to produce goods and services to satisfy consumers.
Figure 17.1 shows the fixed and working capital on a farm, which is the total
investment for any agricultural enterprise. Remember that capital can include
stock as well as money.
Capital
• a factor of production
• a physical and financial resource
• the total investment in the agribusiness
ITQ 1
Draw a table like the one here.
Fixed capital
e.g. spade
Working capital
e.g. diesel
Place these farm items into the
correct column of your table:
tractor, herbicides, cattle antibiotics,
sheep bedding, buildings, irrigation
hoses, pig food, knapsack sprayer.
fixed capital ▶
working capital ▶
stock ▶
cash ▶
depreciation ▶
ITQ 2
Using examples, explain the
difference between fixed capital
and working capital.
246
Fixed or durable capital
Operating or working capital
• buildings
• machinery
• equipment
• land
• stock of materials (consumables):
fertilisers, pesticides, medication, feed, fuel
• money (cash): to purchase land,
planting materials, feed, medication,
fuel, to pay wages for labour / services
• fences
• tree crops
• livestock
• ponds
Figure 17.1 Fixed and working capital on a farm.
A farmer’s capital resources can be divided into fixed (or durable) capital and
working (or operating) capital.
• Fixed capital refers to those items on a farm that have more than one year
of productive life. These are items that need to be renewed only after many
years.
• Working capital refers to those items that are needed for the everyday
running of the farm and that are used up in the production of crops or
livestock.
Working capital can be divided into two further groups:
• stock or consumables, such as feed, fuel, fertilisers, pesticides and medication
• cash needed to purchase land, replenish the stock of materials and pay for
labour and other technical services.
Farm buildings, machinery and equipment undergo depreciation every year.
This means that, each year, they are worth a little less financially. They also
need regular maintenance so that they will continue to work as well as possible.
Eventually the farmer has to replace these items because of their age, as well
as wear and tear. On the other hand, land tends to increase in value, although
farmers have to maintain the soil fertility.
Many farmers may not have the capital they need to run or expand their farming
enterprise. The amount of capital that farmers have available enables them to:
• make decisions about the type and size of the farm, the type of crops to grow
and the best system to use
• decide on the level of mechanisation they can afford
• buy the farm inputs, such as land and stock
17: Farm financing and support services
• employ modern technology
• generate farm income and profits
• develop and improve the farming business
• increase farm assets and values.
Sources of capital
In the Caribbean, farmers may obtain capital, that is money (cash) and / or a stock
of agricultural materials, from the nine different sources.
Agricultural Development Bank (ADB) ▶
Government institutions
Government institutions include the Agricultural Development Bank (ADB),
the Ministry of Agriculture and agricultural societies. The ADB and the agricultural
societies offer loans at low rates of interest, usually from 3–6%. The Ministry of
Agriculture arranges subsidised farm inputs (machinery, equipment, breeding
stock, starter colonies of bees, hybrid seeds and other planting materials). They
also arrange leases for state land.
Commercial banks / enterprises and insurance companies
The rates of interest from commercial banks, insurance companies and financial
agencies are higher than those from the government institutions (8 – 14%). The
commercial enterprises sell land, planting materials, machinery and equipment.
ITQ 3
Name ONE government institutional
bank and state the type of capital
that it can provide to farmers.
Credit unions
Credit unions offer loans at low rates of interest.
Cooperatives and associations
These organisations rent out machinery and equipment and offer loans at low
rates of interest. Depending on the nature of the cooperative or association,
planting materials, breeding stock and starter colonies of bees may be offered.
Sou-sou groups
In these friendly cooperative savings schemes, each person in a small group
contributes an equal portion of money every week or month, as agreed. The sum
of the group’s total contribution goes to one member of the group in rotation,
so that every month, week or fortnight one person benefits from a large sum of
money, interest-free, that can be put to a particular use. In Dominica, the practice
is more often called a ‘sub’. This system was more widespread before banks openly
welcomed small-scale savers and before the credit union movement established
itself in the 1950s and 1960s.
Moneylenders
Loans from moneylenders have high rates of interest and relatively short
repayment times.
Personal savings
The farmer may have saved money over time from the profits of the farm.
Relatives
Relatives may provide capital in the form of a loan at a reasonable rate of interest.
They may also lend the farmer machinery and equipment, or the farmer may
inherit land, cash, buildings or machinery and equipment.
ITQ 4
State FOUR unofficial ways that
farmers can obtain capital.
Friends
Friends may offer loans at reasonable rates of interest. In addition, land, machinery,
tree crops and livestock might be borrowed from a friend in a sharecropping
arrangement.
247
Section D: The business of farming
Obtaining a loan
To obtain a loan from a reliable financial institution, farmers need to fulfil certain
requirements (see Figure 17.2).
farmer’s registration ▶
creditworthiness ▶
farmer’s
registration
lifestyle and
character
credit-rating
and reputation
creditworthiness
Loan
collateral,
security
guarantor
farm
proposal
budget
estimates
farm records
and experience
Figure 17.2 The farmer has to prove
several things before getting a loan.
ITQ 5
Explain why a good credit rating is an
advantage when applying for a loan.
farm proposal ▶
budget estimate ▶
Farmer’s registration
The applicant (farmer applying for a loan) must be a registered farmer. In Trinidad
and Tobago and Jamaica, the farmer’s registration is done by the Ministry of
Agriculture at regional and county agricultural offices. Farmers who are registered
have a better chance of getting loans, subsidies and other national incentives.
Creditworthiness
The creditworthiness or credit rating of a farmer is a measure of the farmer’s
ability to pay off debts. It is determined on the basis of the farmer’s:
• assets, which are items of value such as property
• liabilities, which are things for which the farmer is legally responsible, such as
money owed
• net worth, which is the farmer’s assets minus liabilities.
From the information supplied by the applicant, the lending institution will know
the monthly income and expenses of the farmer. The institution then judges
whether the farmer will be able to repay the loan if it is granted.
Risk and uncertainty apply to agriculture so limited loans are sometimes made to
farmers on the basis of their creditworthiness. Often such loans are not enough
for the farmer to set up a new enterprise that could generate substantial profit.
It is an advantage for a farmer to have a good credit rating and reputation. A
farmer who has borrowed money in the past and has repaid the loan promptly
is treated more favourably than someone who has never asked for credit. The
applicant’s credit rating and reputation are checked by the lending institution as
part of the application process.
The farm proposal and budget estimate
The farm proposal outlines the farmer’s intentions and details the enterprises
the farmer proposes, the farming techniques, the resources needed and the
anticipated output and income.
Using the farm proposal, the farmer prepares and submits a budget estimate
for each of the enterprises he or she intends to develop. The budget estimate
explains the amount of loan required for the proposed farming business. This
information is requested within a standard loan application form. The loan will
not be considered without this form being completed, and budget estimate is
often discussed in an interview.
Farm records and experience
Farm records provide evidence of previous enterprises and indicate the experience
of the applicant. Many farmers keep poor farm records. Without farm records, the
lending institution will not believe the farmer has the ability to run an enterprise
successfully. It is difficult to judge whether a farmer has the experience and skill
to manage a farm successfully if there are no records.
collateral ▶
security ▶
248
Securing a loan
Financial institutions make sure that the farmer has some form of collateral or
security to offer that will cover the total amount of the loan should the farmer
not be able to repay the money. This may be in the form of property, for example,
land, a house, farm machinery, equipment or livestock. Often, a relative or friend
17: Farm financing and support services
guarantor ▶
serves as a guarantor, pledging their own property as security for recovery of the
loan should the farmer fail to repay it.
Lifestyle and character
Honesty, sincerity, perseverance and a determination to work hard are character
traits that are highly regarded. Farmers should aim to be good role models as they
transact business with financial institutions.
ITQ 6
List FOUR requirements that farmers
need to meet when applying for
a loan from a reliable financial
institution.
Loans with high interest rates
Farmers who find it difficult to meet loan requirements may be forced to take
out loans with high rates of interest, or to make repayments over a shortened
period. These types of loans are stressful for farmers, particularly if the agricultural
enterprise is still being developed and not producing much income.
Credit supervision
credit supervision ▶
A farmer who obtains a loan from the Agricultural Development Bank undergoes
credit supervision, where trained staff make regular farm visits, give technical
advice and pay the farmer the money in phases until the enterprise is complete.
This prevents the money being spent on other things.
Practical activities:
1. Practise completing a loan application form for an item of fixed capital, for example, cattle crush or hen house.
2. Research the initial purchasing costs of the item. Then, using the interest rate, calculate how much the farmer would have to repay
over the course of the loan.
3. Collect information from banks and financial institutions about loans and credit facilities for farming enterprises locally.
17.2 Cooperatives
cooperative ▶
ITQ 7
A cooperative is an organisation that enables its members, as a group, to improve
their economic status. A cooperative is a business venture that is collectively
owned, controlled, operated, used and managed by its members on a non-profit
or cost basis, for the economic benefit of all its members.
What is credit supervision and why
is it a key process of some lending
organisations?
A cooperative is different from other business organisations because of its guiding
principles (see Table 17.1). These principles are referred to as the ‘cooperative
concept’ (see Figure 17.3).
Principle
Open membership
Joint ownership
Democratic control
democratic
control
joint
ownership
open
membership
The
cooperative
concept:
Guiding
principles
service
investments
team
management
Team management
Patron-members
patronmembers
Non-profit business
non-profit
business
Figure 17.3 The cooperative concept.
Service investments
Explanation
Membership is open to any person, regardless of gender, race, colour or
creed.
Each member is an owner of the cooperative.
Control of the cooperative is based on each member having one vote and
not on the amount of money a member has invested.
Members operate and manage the cooperative as a team.
Members are the patrons (funders) and the users of the services provided
by the cooperative.
Generally, business transactions do not generate a profit; they aim
to cover the costs only. However, any returns above cost are shared
equitably amongst all the members.
Members invest in the cooperative to be provided with certain services
and not for a profitable financial return.
Table 17.1 The major principles of cooperatives.
249
Section D: The business of farming
Benefits of cooperatives
Cooperatives fulfil the following roles.
• They promote voluntary, open membership.
• They carry out business ventures.
• They encourage active participation and teamwork.
• They generate collective ownership.
• They encourage equity in sharing.
• They operate on a non-profit or cost basis.
• They improve the economic well-being of their members.
• They provide desirable services to satisfy patron-members.
• They generate greater bargaining power for better prices and contracts.
• They attract governmental aid, resulting in benefits for patron-members.
A cooperative helps its members reduce operating costs and increase their
levels of production and, therefore, income. Cooperatives challenge farmers to
produce better-quality produce and become more competitive, thus encouraging
agricultural development and reducing poverty.
Figure 17.4 Jouvay chocolate is made by
the Grenadian Cocoa farmers’ cooperative.
Group demonstrations and technical training sessions are organised more easily
through cooperatives as members share a common focus.
Types of cooperatives
Cooperatives can be grouped in two ways: by their function or by their links with
other groups.
Cooperatives grouped by function
There are seven types of cooperatives (see Table 17.2), which perform different
functions.
Type of cooperative
Produce
Consumer
Purchasing
Processing
Marketing
Commodity
Service
Function
Members take part in joint-venture production enterprises,
producing a range of products that are collectively owned.
This is organised for the bulk buying of consumer products for the
membership. The cooperative is owned, operated and managed
by its members.
This is engaged in bulk purchasing and supplying of raw
materials, such as planting material, feed, chemicals and
fertilisers, to its members.
In this type of cooperative, packing, processing or manufacturing
of farm products (fruit, vegetables, milk and meat) from members
is carried out.
This is organised by its farmer members to collect, grade,
package and sell their produce.
Members focus on production of the same commodity so the
cooperative is named accordingly, for example, Cooperative
Citrus Growers, Dairy Farmers’ Cooperative and Cedros Fishing
Cooperative.
Each cooperative provides one or a combination of essential
services to members. For example, there are service cooperatives
for credit, livestock breeding and farm machinery.
Table 17.2 The functions of different types of cooperatives.
250
17: Farm financing and support services
Women’s farming cooperatives in rural Jamaica
There are thousands of farmer cooperatives in Jamaica, although only a few offer membership solely to women. In the
Milbank and Cambridge areas of Portland, women’s ginger farming cooperatives are facilitated by the Rural Agriculture
Development Authority (RADA). RADA supports them with the exportation of the ginger crop. One young woman from
Milbank was attracted to farming by this arrangement and started to farm ginger in 2013. By 2017, she was farming two
acres of ginger, as well as banana and plantain. She has benefited from the seeds and advice in the cooperatives and
uses intercropping techniques as well as a drop irrigation system on her farm. However, she also works in a bank
as she could not sustain an income just from farming. The challenges that affect most cooperatives include lack
of management and leadership, lack of adequate finance (membership fees are often too low for funds
to be built up adequately so members do not take the cooperative seriously), poor cooperation and an
unwillingness to offer mutual support for the common good.
(Source: Information from: Ishemo, Amani and Bushell, Brenda (2017). Farming Cooperatives:
Opportunities and Challenges for Women Farmers in Jamaica. Journal of International
Women’s Studies, 18(4), 13–29.)
Cooperatives grouped by links
Most cooperatives are linked in groups at local, regional and national levels.
• Local cooperatives offer members representation and services at the village or
district level.
• Regional cooperatives provide services and representation at the county or
regional level, based on nominees from local cooperatives.
• National cooperatives supply representation and services at national level,
through nominees from the regional cooperatives, who are representatives of
local groups.
ITQ 8
What are the major principles of
cooperatives?
business
volume
membership
issues
local
competition
managerial
inefficiency
limited
capital
Problems
global
issues
Figure 17.5 Some problems in managing
a farmers’ cooperative.
There are also:
• independent cooperatives, which are not linked to any other cooperatives
• federated cooperatives, which are made up of small local cooperatives that
operate as a unit and band together to gain greater economic power and
efficiency
• centralised cooperatives, which are composed of delegates from local
cooperatives. They operate as a centralised control unit and initiate directives
from the local cooperatives for action. The structure of the centralised
cooperatives means that each member cannot participate directly in the
decision-making process.
Management and problems in a farmers’ cooperative
Management of a farmers’ cooperative is a shared responsibility between the
chief executive officer, the board of directors and the patron-members. Policies
and regulations drawn up by the board and approved by the general membership
are used for the day-to-day running and management.
Management is aimed towards the economic well-being of the farmers, who are
the patrons, users and owners of their cooperative. Approved policies are used to
achieve results using the limited resources available. Problems may sometimes
arise for the management team (see Figure 17.5).
251
Section D: The business of farming
Limited capital
Cooperatives operate with limited amounts of finance (or capital), which
come from its patron-members. As funds cannot be generated through public
investment, the cooperative may have to look for credit or ask patron-members
for more money to finance the necessary services. It is important that the farmer
elected as the manager or chief executive officer has the skills and experience to
make decisions.
Practical activities:
1. Visit an established farmers’
cooperative and find out how it
is organised and managed.
2. Find out about the different
types of cooperatives in your
area.
Business volume
The volume of business transactions changes as it depends on how often members
use the services they have provided for themselves. High levels of business volume
help a cooperative, so it is up to members to ensure that they use the services to
sustain their cooperative.
Membership issues
In a cooperative, each member is a patron, a user and an owner. Every member
needs to demonstrate a sense of ownership, loyalty and commitment. Members
need to face up to the shared responsibility of supporting their cooperative
investment with their share contributions and business patronage.
Local competition
Cooperatives often face competition from the local business community who
feel that they are an economic threat to their clients and business. Large local
businesses buy in bulk and get discounts from merchant suppliers. When the local
businesses sell their goods, they may offer lower prices than the cooperatives do.
Members of cooperatives need to focus their efforts on good management, greater
production and better quality.
Global issues
Issues such as globalisation, trade liberalisation, competitiveness and quality
standards affect farmers’ cooperatives directly. Such issues may make it difficult for
cooperative managers to meet the challenging task of international requirements
and to educate, train and motivate their members.
17.3 Incentives available to farmers
Risk and uncertainty
ITQ 9
State FOUR factors that make the
Caribbean agricultural sector a
higher risk for investors.
252
The agricultural sector is affected by factors that involve risk and uncertainty.
These include:
• the weather (including hurricanes)
• natural disasters (volcanic eruptions and earthquakes)
• over-production and under-production
• changing market prices
• increasing cost of inputs
• unstable incomes for farmers.
Governments can help to stabilise production, market prices and farm incomes
through price support policies and subsidies.
17: Farm financing and support services
Price support
guaranteed prices ▶
Farmers can be guaranteed minimum cost-based prices by the government,
referred to as guaranteed prices, for selected crops or commodities. The
commodities may be export-oriented (sugar cane, cocoa, coffee, citrus fruits and
bananas) or for domestic consumption (rice, root crops, milk, mutton and eggs).
These guaranteed prices are incentives to production. The guaranteed prices show
that the government is committed to helping farmers.
Subsidy
subsidy ▶
A subsidy is an amount of money that the government is willing to pay a
business to help the business achieve a specific goal. Subsidies are sometimes
given to farmers or producers so that they can develop their farm infrastructure,
improve their technical operations or even establish new agricultural enterprises.
Normally, a government subsidy will pay only a portion of the total cost.
tax exemptions ▶
In many Caribbean countries, there are tax exemptions for agricultural inputs
and import duty concessions on farm machinery. Most domestic unprocessed
foods are exempt from general consumption tax. These measures encourage
agricultural enterprises and create employment in the agricultural sector.
ITQ 10
What is the difference between price
support and a subsidy?
Practical activity:
Working in groups, choose ONE
commodity that is exported and
ONE commodity that is produced
for domestic consumption. For each
of the chosen commodities, find out
what benefits the producer gains
from price supports and subsidies.
Each group should create a
presentation, then feedback to the
class with what they have learnt.
The purpose of price supports and subsidies
The main functions of price supports and subsidies are to:
• speed up the growth of agricultural output
• stabilise agricultural production, market prices and farm incomes
• increase the local market supply of commodities for home consumption and
export
• speed up or encourage growth in the output of specific commodities
• provide a more regular income for farmers and producers.
In addition, these incentives enable the government to achieve its targets in
agriculture and to speed up innovation in farming.
253
Section D: The business of farming
Revision map
Government
institutions include
the Agricultural
Development Bank
and the Ministry
of Agriculture
Capital enables
the farmer to plan,
develop and operate
the farm efficiently
and profitably
Working capital
are items needed
for the day-to-day
running of the
farm
Fixed capital is
land, buildings,
machinery and equipment
that do nothave
to be purchased
every year
Capital is a
factor of production
that is made up of fixed
(or durable) capital
and working
(or operating)
capital
Commercial banks
and insurance companies
charge higher rates of
interest than the
government
institutions
Credit unions
and cooperatives
also lend money
to farmers
Other sources
of credit are
moneylenders,
friends and
relatives
Caribbean farmers
usually obtain capital
(money) from their government,
as well as from private financial
institutions at varying
rates of interest
Capital
Collateral
Farming
experience
Farmers seeking
loans from reputable
financial institutions
must fulfil certain
requirements
Good credit
rating
Lack of
collateral
Many farmers
find difficulty in
obtaining
agricultural
credit
Limited
loans
Short
repayment
period
Farm financing
and support
services
High
interest
rates
Open
membership
Democratic
control
A cooperative is a
business venture owned
and operated by its members
on a non-profit or cost basis
for the economic well-being
of its members
Patron-members
Team
management
Management
of a cooperative
is a shared
responsibility
A cooperative
helps its
members
Non-profit
business
investments
Reduce
operating
costs
254
Price supports
and subsidies instituted by
government help to stabilise
agricultural production,
market prices and
farm incomes
Cooperatives
Increases
their levels of
production
Become
more
competitive
Needs
managerial
ability, skills and
experience
Must be
goal-oriented,
addressing problems
pro-actively in a
dynamic global
environment
17: Farm financing and support services
Examination-style questions
Multiple-choice questions
Write down the number of the question followed by the letter of the correct answer.
1.
2.
3.
4.
5.
Which of the following is NOT considered to be part of the working capital on a farm?
A Cost of feed
B Farm machinery
C Fuel
D Labourer’s pay
Which of the following financial institutions offers loans at the highest rate of interest?
A Agricultural Development Bank
B Credit unions
C Agricultural societies
D Commercial banks
A subsidy is an incentive to farmers in the form of:
A a guaranteed price for citrus fruit exports
B financial assistance for irrigation equipment
C set minimum prices for milk and eggs
D tax exemption.
The function of a commodity cooperative is to:
A purchase raw materials in bulk for its members
B collect, grade, package and sell the produce of its members
C process and manufacture farm products
D focus on producing one product.
A regional cooperative:
A is not affiliated to any other cooperative
B consists of several small cooperatives
C has representatives from smaller cooperatives
D sends representatives to smaller cooperatives.
Short-answer and essay-type questions
6.
(a) Explain the meaning of ‘capital’ as it relates to agriculture.
(b) Listing TWO examples of each, differentiate between (i) fixed or durable capital and
(ii) operating or working capital.
(c) Why does a farmer have to eventually replace or upgrade fixed or durable capital?
7. (a) List FIVE sources from which farmers may obtain agricultural credit (finance).
(b) Explain why most farmers prefer to borrow capital (money) from government
institutions.
8. (a)With reference to agricultural loans for farmers, explain the meaning of (i) collateral
and (ii) guarantor.
(b) State the importance of collateral.
(c) What is the role of a guarantor?
9. In procuring agricultural credit, farmers may encounter several problems.
(a) List FIVE main problems that farmers may encounter.
(b) Discuss any THREE of the problems you have listed.
10. (a) List FIVE major roles for which cooperatives may be designed and organised.
(b) Explain the importance of cooperatives in local agricultural development.
11. (a)List FIVE problems that may arise as challenges for the management team of a
cooperative.
(b) Discuss the procedures for managing any TWO of the problems you have listed.
12. (a) Using examples, explain the difference between (i) price support and (ii) subsidy.
(b) Explain why subsidies and price support policies are instituted by government.
255
Section D: The business of farming
18
Farm
organisation
and planning
By the end of this unit you should be able to:
✔ prepare different types of farm records
✔ calculate gross farm income, net farm income, gross margin and net profit
✔ differentiate between a complete budget and a partial budget.
Concept map
Preparing farm records
Farm planning
Short-term
Long-term
Farm records
Farm inventory
Production records
Records for rabbit production
Records for crops
Chemical records
Chemical treatments
256
Farm organisation and planning
Income and expenditure
Profit and loss account
Income
Production record
Gross income
Net income
Net profit
Gross margin
Complete and partial budgets
Budgeting
Complete budget
Partial budget
18: Farm organisation and planning
18.1 Preparing different types of farm records
farm plans ▶
ITQ 1
What are the advantages of farm
planning?
Farm management is essential in agriculture to ensure profitability. Farm plans
outline the intentions of the farmer regarding the use of resources, the business
enterprise and the expected production.
There are four questions to be answered before starting on any new agricultural
enterprise.
• What to produce?
• Why choose this product?
• How much can be produced?
• How will optimum production be achieved?
The choice of product is determined by factors such as the location of the farm, the
experience of the farmer, the demand and market price of the commodity, and
the resources available. A detailed farm plan removes some of the uncertainty in
the new enterprise and enables the farmer to apply for financial support. It also
helps the farmer organise the use of resources. Continued recording of progress
will provide information for future decisions.
short-term planning ▶
Short-term planning relates to an enterprise’s plans for one year or less than
one year if the enterprise has a short production cycle. The main objective is to
make as much profit as possible, so the farmer chooses crops and livestock that
will provide income in a few weeks or months, on a continuing basis. Products
with short-term production cycles include vegetables such as pak-choi, tomatoes
and beans and poultry (broilers, ducks).
long-term planning ▶
Long-term planning focuses on periods of longer than one year. Usually,
plans are made for enterprises that need some time to become established before
production begins. Examples are tree crops (citrus, mango, avocado) and dairy
farming (heifers and cows for milk production).
The objective of long-term planning is to develop and expand resources on the
farm so that the earning capacity and asset value of the farm will increase in the
future. However, a farmer should undertake one or two short-term enterprises to
produce some income until the long-term projects become productive.
Figure 18.1 Poultry farming is a shortterm enterprise.
Figure 18.2 Growing soursop is a long-term enterprise. These photos show a cutting in pot
(left), a tree in flower (centre) and a tree with fruit (right).
Farm records
farm records ▶
Farm records store essential data about all the agricultural enterprises on a
farm. The data should include records of transactions, costs, information and
observations. A farmer may be able to remember some of the transactions carried
out on a day-to-day basis, but he or she cannot remember details of figures,
quantities and dates so it is vital for the farmer to keep accurate written records.
257
Section D: The business of farming
easily done
and kept
Figure 18.3 shows the characteristics of good farm records. The different types of
farm records are summarised in Table 18.1.
for prompt
follow-up action
accessed or
retrieved easily
Good
farm
records
for a definite
purpose
kept
consistently
essential
information
accurate,
complete
simple, useful,
effective
Figure 18.3 The characteristics of good
farm records.
Type of record
Inventory
Production
Chemical treatment
Financial
Labour
Consumables
Examples
Land, machinery, tools and equipment, buildings, livestock, field crops
Crops, livestock, breeding, milk production, egg production, feed
conversion ratios
Pesticides, fertilisers, livestock medication, dates, application rate and
purpose
Profit and loss account, assets, liabilities, balance sheet
Personnel, permanent, casual, seasonal, contract, family
Seed, fertilisers, pesticides, feed, medication, fuel
Table 18.1 Types of farm records.
Farm inventory
farm inventory ▶
A farm inventory is a record of the farm resources, describing the quantity and
value at the beginning and end of an accounting period. An accounting period is
usually one calendar year. A farm inventory holds information about the land,
machinery, tools and equipment, buildings, livestock, field crops and materials.
Inventory records may be done collectively or separately for each of the resources,
such as land, machinery and buildings. Farmers with large farms prefer separate
inventories for each resource because it is easier to show continuity on a yearly
basis. The information on each resource can be found more easily and necessary
action can be taken more promptly. Figure 18.4 shows an example of a separate
inventory system for tools and equipment.
Depreciation US$
Description
Date owned
Years life
Total cost
US$
Annual
Total
to date
Balance
Weed wacker x 1
Knapsack sprayer x 2
Garden fork x 1
01/01/18
01/01/19
01/01/18
6
10
10
2 400
400
75
400
40
7.5
800
40
15
1 600
360
60
2 875
Total
2 020
Figure 18.4 An inventory of tools and equipment.
Production records
production records ▶
258
Production records are used for crop and livestock enterprises to follow the
progress and determine the performance and productivity of different crop
varieties and animal breeds. With such records, farmers can find out whether
inputs, such as feed and fertiliser, are being used efficiently. For example, livestock
records can be kept to show the milk production of individual cows or the feed
conversion ratio (FCR) when a particular type of feed is used to fatten weaners.
Similarly, there are record forms for egg production and other types of livestock
enterprises, such as rabbit and broiler production.
18: Farm organisation and planning
Records for rabbit production
Records for rabbit production should include:
• an animal inventory that describes the total number of bucks, does and
weaners
• breeding records for each buck and doe with breeding dates, including
number in each litter of each doe, number of live births and mortality, and
remarks (for example, whether the doe was a good mother)
• feeding records that describe feed given, feeding regime, growth rate and feed
conversion ratios
• medication records
• records that describe weight at marketing or slaughter, cost of production and
income from sale.
From the records, a farmer can work out whether the enterprise makes a profit
or a loss. The records also highlight areas where savings or improvements can be
made to make the enterprise more profitable in the long term. When assessing
the enterprise, the farmer also needs to take into account the cost of the buildings
and the labour.
Records for crops
Crop production record forms show the performance of the crop variety, the yield
and how much profit (or loss) was made. Figure 18.5 shows an example of a
record form for a crop of lettuce.
Crop:
Lettuce
Variety:
Iceberg
Inputs / Items
Type
Amt. planted or
hectarage:
3 000 heads
Quantity
Planting date:
04/06/2019
Cost (US$)
Fertilisers
Urea
Nutrex
50 kg
2 kg
350.00
90.00
Pesticides
Malathion
Cupravit
0.5 ℓ
0.5 kg
95.00
85.00
Harvesting date
or period:
19–23/07/2019
Remarks
Total cost of
production
Yield / Output
Gross income
Profit / (Loss)
Figure 18.5 A record form for iceberg lettuce.
Chemical records
chemical treatments ▶
ITQ 2
Describe the uses of production
records.
Any treatment given to crops or livestock is a consumable resource, and needs
to be offset against any profit made. Chemical treatments include fertilisers
and pesticides for crops, and medication, concentrates and drugs for livestock. All
farms need locked chemical stores where records are kept of exactly what is in the
store. Chemicals should be used up before new stocks are purchased. Figure 18.7
shows a record form for a chemical store. In the ‘Remarks’ column, the farmer
should record the crop that needed this chemical. This can be cross-referenced to
the entry on the crop record. The cost of the chemical is offset against the profit
from sale of the crop.
259
Section D: The business of farming
Consumable item: Fertiliser – Urea
Purchases
Quantity
purchased
Date
Figure 18.6 Fertiliser.
Utilisation
Quantity
in stock
Date
Quantity
used
Remarks
Figure 18.7 Chemical store record.
18.2 Income and expenditure
income ▶
expenditure ▶
Agricultural enterprises need to keep financial records about their income (farm
receipts) and their expenditure (farm expenses). In small agricultural enterprises,
the financial records may take the form of an income and expenditure statement.
The farmer will use the records to determine the farm’s profit or loss.
In larger businesses, the financial records include:
• the profit and loss account (referred to as the cash account)
• records about the assets of the farm
• records about the liabilities of the farm
• the balance sheet or net worth statement.
Profit and loss account
profit and loss account ▶
Figure 18.8 shows a profit and loss account for one month. The income is
on the left-hand side and gives details of produce sold and price achieved. The
expenditure is on the right-hand side and includes the expenses relating to labour,
fuel and other consumables. The only details missing from this account are the
quantities of produce sold and the consumables used. This information would
appear on the records for each enterprise on the farm.
A
1
C
B
Dr.
D
Receipts (Income)
F
Cr.
Value (US$)
Particulars
Value (US$)
2
Date
3
July 02
Cabbage
450.00
July 01
Labour
450.00
4
July 08
Bodi beans
210.00
July 05
Seedlings
180.00
5
July 12
Eggs
320.00
July 09
Fertiliser
120.00
6
July 16
Cassava
150.00
July 15
7
July 21
Pak-choi
120.00
July 23
Insecticide
Feed
160.00
8
July 26
Eggs
Fuel: Pick-up
150.00
July 30
Ochro
300.00
140.00
July 28
9
July 31
Electricity
110.00
1 690.00
Total
Particulars
Date
G
Expenses (Expenditure)
90.00
10
11
Total
Figure 18.8 A profit and loss account for July.
260
1 260.00
18: Farm organisation and planning
balance sheet ▶
The balance sheet, or net worth statement, shows what is left of the value of the
assets after all claims and liabilities against the business have been paid.
net worth = assets – liabilities
Figure 18.9 shows a balance sheet. The assets include the land, buildings,
machinery, equipment, field crops, livestock and cash. The liabilities include
unpaid rent, wages, mortgage (loan) commitment and money owing to creditors.
Net worth is the farmer’s assets minus the liabilities.
B
A
D
Value (US$)
Assets
1
C
E
Value (US$)
Liabilities
28 000.00
2
Land
125 000.00
Wages
3
Buildings
60 000.00
Rent
1 200.00
4
Machinery and equipment
45 000.00
Mortgage
65 000.00
5
Field crops
10 000.00
Creditors
35 000.00
6
Livestock
15 000.00
Total liabilities
129 200.00
7
Cash
50 000.00
Net worth
175 800.00
8
Total assets
305 000.00
304 200.00
9
Figure 18.9 A balance sheet (net worth statement).
Income
income ▶
Income is money earned by producing commodities that are in demand and
selling them at current market prices to wholesalers, retailers and consumers.
After subtracting the costs of production, the farmer uses the income to purchase
necessities for the family, educate children, invest in savings and buy the inputs
required to continue the farm operations.
To calculate income, several factors have to be considered:
• fixed inputs and fixed costs (total fixed cost)
• variable inputs and variable costs (total variable cost)
• output and the market price gained (total income).
Production records
Figure 18.11 shows a production record for a duck-rearing enterprise. All the
costs are set out and the total income is shown.
Figure 18.10 Ducks.
A
C
B
E
F
Variable costs
(US$)
Output/Yield
& market price
1 500 live ducks at
5 kg each (avg wt)
7 500 kg at
$12.00 per kg
(Wholesale market
price)
Income
(US$)
Fixed costs
Variable inputs
2 Land rental
60.00
Muscovy ducklings
6 000.00
3 Building depreciation
500.00
250.00
Feed
15 000.00
1
Fixed inputs
D
4 Equipment depreciation
Medication
500.00
5 Vehicle depreciation
900.00
Labour
12 000.00
6 Insurance
550.00
Electricity
550.00
7 Loan interest
240.00
Gasoline (Fuel)
850.00
8
Total Fixed Costs
9 (T.F.C.)
= 2 500.00
Maintenance
Total Variable
Costs (T.V.C.)
7 500 kg
x $12.00
= $90 000.00
600.00
= 35 500.00
7 500 kg x $12.00
= $90 000.00
= 90 000.00
Figure 18.11 A duck production record.
261
Section D: The business of farming
gross income ▶
In Figure 18.11, you can see that the total income is the market price multiplied
by the weight of ducks sold. This is US$ 90 000 and represents the gross income,
which is the income without subtracting the cost of the inputs.
gross income = total income
net income ▶
The net income is the gross income minus the total cost of the inputs (the total
fixed cost plus the total variable costs).
In this case, the total cost of the inputs is US$ 35 500 plus US$ 2 500 (this equals
US$ 38 000) and US$ 90 000 minus US$ 38 000 is US$ 52 000. So the net income
is US$ 52 000.
ITQ 3
Explain the meaning of the terms
‘farm income’, ‘gross income’ and
‘net income’.
gross margin ▶
net profit ▶
Having seen how net income is worked out for one agricultural enterprise, it is
easy to see how gross farm income and net farm income can be calculated. The
farmer needs to add up the gross income from all the enterprises, add up the total
cost of the fixed and variable inputs, and use these figures to calculate a net farm
income.
Two other terms often used in connection with balance sheets are gross margin
and net profit. Gross margin is equal to gross income minus variable costs. It is
the difference between the sales and the production costs.
gross margin = gross income – variable costs
Practical activity:
Use examples of farm records
provided by your teacher to
determine whether or not an
agricultural enterprise is profitable.
Gross margin shows the farmer how profitable the enterprise is. Those agricultural
businesses with higher gross margins will have more money left over to spend on
other operations.
Net profit is a measure of profit over time and it is calculated by subtracting all the
costs of a business from the receipts. This means subtracting all the costs from the
gross profit. Net profit can be shown on the profit and loss account for a business.
18.3 Complete and partial budgets
budgeting ▶
ITQ 4
What is meant by the term
‘budgeting’?
complete budget ▶
262
Budgeting is estimating the quantity of inputs, costs, outputs, income and profit
related to an agricultural enterprise. It focuses on the physical components (what
to produce, how to produce it and how much to produce) and the financial
components (anticipated costs, returns and profit).
Budgeting is an essential process in farm planning.
• It helps the farmer to decide which farm plan or agricultural enterprise to
choose.
• It allows the farmer to compare the profitability of different enterprises.
• It makes the preparation of whole farm budgets easier.
• It provides documentary evidence for financial institutions when a loan
application is made.
• It makes it easier for the farmer to control the finances of the farm.
A complete budget is also known as a total budget or a whole farm budget. It
is prepared for a farm that has a new owner or new management. It can also be
used when there is a major change in the resources and enterprises of a farm, or
when a complete re-organisation is undertaken. It is usually prepared when an
existing farm wants to change its systems of production and introduce improved
technology (see Figure 18.12).
18: Farm organisation and planning
partial budget ▶
ITQ 5
Describe the important features of
a partial budget.
A partial budget is prepared when there is a change in a specific aspect of the
existing farm plan that requires some modification to the budget. For example,
a farmer may want to know whether replacing one crop with another crop
would be more profitable or buying a pick-up truck instead of hiring one. In
such situations, most of the income (receipts) and expenses (costs) in the existing
budget will remain the same and only a few of them will change. A partial budget
identifies the income and expenses that will change and sets out how additional
costs and income will affect the change in profit.
3 000.00
15 000.00
36 000.00
US$
1 500.00
2 500.00
1 200.00
3 000.00
6 000.00
650.00
550.00
6 500.00
750.00
270.00
1 200.00
750.00
1 500.00
Practical activity:
Prepare complete budgets for
crop production projects. Using
the example given here, prepare
a partial budget for changing 30
acres of corn to 30 acres of cassava.
ITQ 6
How does budgeting help a farmer
with decision-making?
= T.I. – T.V.E
= $54 000.00 – $22 650.00
= $31 350.00
= T.V.E. + T.F.E.
= $22 650.00 + $3 270.00
= $25 920.00
= Total income (T.I.) – Total expenses (T.E.)
= $54 000.00 – $25 920.00
= $28 080.00
Figure 18.12 A complete budget for a mixed farm.
Cassava development in the Caribbean
Cassava is a useful crop to grow because it tolerates acid soils, periodic and extended drought,
and defoliation by pests. It also grows well with different types of intercrop and is flexible in the time
of harvest. Cassava is recognised as a low-cost, high-quality energy source. Due to this, the cassava market
is being developed to provide starch for industries and dried cassava for animal feed.
In urban areas, the lowest income families will consume the low-cost, starchy cassava root. The rural poor farmers
also benefit, as cassava grows in marginal land.
In the Caribbean, more small-to-medium sized growers are investing in cassava development. To make cassava products
more competitive with alternative energy sources, processing will move to larger, more efficient plants. Development of the
industry would mean increasing productivity of the cassava plants through increased soil fertility, reduced soil erosion and an
integrated pest management program to maintain healthy tubers.
263
Section D: The business of farming
The financial gains and losses are set out in the partial budget as:
• debits, which are additional costs and reduced income
• credits, which are additional income and reduced costs.
Positive effects
Value (US$)
Negative effects
Value (US$)
Reduced income:
Additional income:
100 acres of soybeans
× 35 bushels / acre
× US$7 / bushel
24 500
100 acres of corn
× 100 bushels / acre
× US$ 2.80 / bushel
28 000
Total additional income
24 500
Total reduced income
28 000
13 000
Additional costs:
100 acres of soybeans
× US$ 75 cost / acre
7 500
Reduced costs:
100 acres of corn
× US$ 130 cost / acre
100 acres of corn
× 3 hours / acre
× US$ 5 / hour
Total reduced costs
Total additional income
and reduced costs
1 500
14 500
39 000
100 acres of soybeans
× 2.5 hours / acre
× US$ 5 / hour
Total additional costs
Total reduced income
and additional costs
Change in net income: (total additional income and reduced costs) minus
(total reduced income and additional costs)
1 250
8 750
36 750
2 250
Figure 18.13 Partial budget showing the effect that replacing 100 acres of corn with 100 acres of soybeans would have.
264
18: Farm organisation and planning
Revision map
Long-term
planning involves
enterprises which
take from 1–3 years
to come into full
production
Financial
Consumables
Production
Labour
Inventory
Farm planning
may be short-term
for enterprises taking
less than a year or for
those that can be
completed in a short
production
cycle
Farm planning
is essential for the
proper use of resources
and the development
of agricultural
enterprises
Farm
record-keeping
is the process of
registering essential
data of agricultural
enterprises
Farm planning
Farm
record-keeping
Provide valuable
information
for farm planning,
decision-making
and budgeting
Farm
organisation
and planning
Gross farm income
refers to the total
income from all the
farm enterprises
Calculating
income, gross
margin and
net profit
The net income
is the gross income
minus the total
costs of the
inputs
Budgeting
Budgeting is
estimating the quantity
of inputs, costs, outputs,
income and profit of
a farm plan
A partial budget is
drawn up when there is a
proposed change in the nature
of an agricultural enterprise,
e.g. increasing the
number of livestock
A complete budget,
sometimes known as a
whole farm budget or total
budget, is usually drawn up
when a farm has a new owner
or is under new management.
It consists of all the assets
and liabilities
265
Section D: The business of farming
Examination-style questions
Multiple-choice questions
Write down the number of the question followed by the letter of the correct answer.
1.
2.
3.
4.
5.
Long-term planning is used for the production of:
A broilers
B milk
C lettuces
D tomatoes.
Which type of farm records are used for recording the amounts of fertiliser used?
A Inventory
B Production
C Financial
D Consumables
A farming enterprise recorded that the income from the sale of broilers was US$ 80 000. The fixed costs were
US$ 2 500 and the variable costs were US$ 26 000. The farm profit was:
A US$ 80 000 + US$ 2 500
B US$ 80 000 – US$ 2 500
C US$ 80 000 – US$ 28 500
D US$ 80 000 – US$ 26 500.
Gross margin is:
A gross income – variable costs
B gross income – fixed costs
C gross income – total costs
D gross income – net income.
Variable costs change with:
A the market price
B the depreciation of the machinery
C the level of production
D the rent of the land.
Short-answer and essay-type questions
6.
7.
8.
Discuss the statement ‘decision-making is regarded as the heart of farming’.
Describe TWO beneficial effects of sound decision-making.
(a)Using examples, differentiate between (i) short-term planning and (ii) long-term planning.
(b) State the major objective of (i) short-term planning and (ii) long-term planning.
(c) Why should farmers include one or two short-term farm enterprises in long-term agricultural projects?
9. (a) Explain the meaning of ‘budgeting’ in relation to farming.
(b) State the importance of ‘budgeting’ in agriculture.
(c) Differentiate between (i) a complete budget and (ii) a partial budget.
10. (a) Differentiate between (i) a farm plan and (ii) a farm budget.
(b) Explain why it is important for the farmer to prepare both a farm plan and a farm budget.
11. (a) Explain the meaning of the term ‘farm record-keeping’.
(b) What are FIVE major characteristics of good farm records?
(c) State FOUR advantages of farm record-keeping.
12. (a)List THREE major kinds of financial records that farmers of large-scale enterprises should keep.
(b) Differentiate between (i) assets and (ii) liabilities.
(c) State the importance of financial records.
266
19
Section D: The business of farming
Marketing of
agricultural
products
By the end of this unit you should be able to:
✔
✔
✔
✔
Concept map
Role of
marketing
Agricultural marketing
Identifying market
segments
Market research
Domestic market
segments
discuss the role of marketing in agricultural production
identify the steps of marketing
explain the process involved in the marketing of agricultural products
explain the importance of international trade agreements on the
agricultural sector and peoples of the Caribbean.
Marketing of agricultural products
Steps of
marketing
Pricing
Advertising
Labelling and packaging
Distribution
Assembling
Sorting and grading
Processing
Storage
Transportation
Marketing agricultural
products
Crops
Eggs
Meat
International trade
agreements
Caribbean Single Market
and Economy (CSME)
Goods
Services
Capital
People
World Trade
Organization (WTO)
Economic Partnership
Agreement (EPA)
The EPA
Benefits
Caribbean Basin
Initiative (CBI)
267
Section D: The business of farming
19.1 The role of marketing in agricultural
production
Agricultural marketing
agricultural marketing ▶
Agricultural marketing includes all the services involved in moving an
agricultural product from the farm to the consumer. A large number of activities
are involved in doing this: planning, planting, growing, harvesting, grading,
packing and packaging, agro- and food processing, distribution, advertising and
sales.
Both the livestock and the grain sectors are changing from industries dominated
by family-based, small and modestly sized, relatively independent firms to larger
businesses that are driven by profit. Farmers and business owners are adopting new
technologies that use economies of scale (producing more units, while keeping
the fixed costs the same). At the same time, the consumers and processors of food
products are expecting increased quality and safety through knowing where the
products originated.
Identifying market segments
Market segmentation splits up a market into different types (segments) to enable
businesses to aim their products at the relevant customers.
Table 19.1 describes how market segmentation can benefit a business in different
ways.
Benefit
Matching customer needs
Higher profits for business
Opportunities for growth
Customer retention
Target marketing
communications
ITQ 1
Explain THREE benefits of market
segmentation.
Share of market segment
Explanation
Customers are different. Sometimes separate products are needed
for each market segment.
Customers have different incomes. By segmenting markets,
businesses can raise average prices.
Market segmentation can build sales. For example, customers can
be encouraged to buy more products or more expensive products
after buying an introductory, lower-priced product.
By marketing products that appeal to customers at different stages
of their lives, a business can keep customers who might be thinking
of buying a competitor’s product instead.
Marketing messages need to appeal to the target customers. By
segmenting markets, the messages can reach target customers
more often and at a lower cost.
Through careful segmentation and targeting, businesses can become
competitive and their products the preferred choice of customers
and distributors.
Table 19.1 Benefits of market segmentation.
market research ▶
ITQ 2
Why do companies do market
research?
268
Market research
Market research is the action or activity of gathering information about
consumers’ needs and preferences.
Most businesses have information formed by their own knowledge and experience
of the marketplace, but there is a constant need to improve and update this
information. The purpose of market research is to find out as much as possible
about the marketplace so that the customers can be given what they want, when
they want it.
19: Marketing of agricultural products
Practical activities:
1. In groups, design
questionnaires to present to
different market segments
(such as supermarkets, hotels
and other buyers).
2. The questionnaire should
ask about the products each
market segment buys from
different sources. Include
questions to find out what
the buyers are looking for
when they source agricultural
produce.
3. When you are back in class,
discuss how the information
you have learnt could influence
production decisions, and how
each market segment has
different needs.
4. Each group should produce a
short report about the market
segments and how different
production can help to meet
each market segment’s needs.
Domestic market segments for agricultural products
Farmers can sell their products domestically (within their country) to anyone
who eats or processes the products.
Market segment
Individual
Supermarket or
specialist shop
Hotel
Food-processing
factory
School canteen
Catering or fast food
companies
Table 19.2 Domestic markets for agricultural products.
19.2 The steps of marketing
There are a number of steps in marketing. Table 19.3 shows some of the steps that
are related to agricultural products.
Steps
Pricing
Advertising
Labelling and
packaging
Distribution
Assembling
Sorting and
grading
Processing
Practical activities:
1. Research samples of marketing
plans using the internet.
2. Review local products in a
supermarket and write a
critique of each label.
Common source of agricultural products
People usually buy food for their household at a local market.
Some packaged foods are sold in supermarkets or specialist shops, such as
butcheries. Supermarkets also sell local produce such as eggs, poultry and
salad foods.
Some farmers have arrangements to supply hotels with salads, vegetables
and other foods.
Farmers can sell their raw products to a processing business to generate a
processed product, for example, chicken, jam.
School canteens need food to prepare meals for students. When students
are on holiday, this market will not be available.
Produce can be used in companies that work both domestically and
internationally. Certain Caribbean produce is exported around the world, for
example, bananas, pineapples.
Storage
Transportation
Explanation
The price of a product will determine its success or failure. Factors such as
demand, market conditions and competitor prices need to be considered. Prices
should not be changed too frequently, as this leads to confusion in the market.
Once the market segment has been selected and research has found out what
the customers want, product advertising should focus on the target audience.
The customer will look at the label and package and form a first impression of
your product. It should be clear what you are selling. Sometimes, information
about how it was produced is a unique selling point. For example, an
international hotel may pay more for organic peppers.
Distribution is choosing where you are going to sell your product. Selecting the
most appropriate distribution channel for a product is crucial. Online retail is
growing rapidly in many industries, but if 99% of products similar to yours are
sold in supermarkets, then distribution to online retailers could be a waste of
time and money.
This refers to the process of keeping goods, purchased from different places, at a
particular location. This ensures there will not be an interruption in raw materials
to make a product.
Sorting involves discarding the products that are damaged, diseased, too small
or overripe. Grading is classifying products according to characteristics or quality.
Often washing is done between these two steps.
Processing increases the value of raw materials by converting them into highervalue products that consumers want.
There is always a delay between the production and the consumption of goods.
Sometimes the products are seasonal, the supply is irregular or there are
production difficulties. Companies like to maintain a smooth flow of goods, so
appropriate storage and warehousing is necessary.
Transportation is the physical movement of the goods from their place of
production to their place of consumption. The geographical boundaries of
the market, along with how perishable the goods are, will determine the
transportation needed.
Table 19.3 The steps in marketing.
269
Section D: The business of farming
19.3 The process of marketing agricultural
products
Preparation of crops for sale
Fruit vegetable crops such as tomato
• Fruit should be graded according to size and variety and then packaged in
clean polythene bags for sale.
• Fruit should be handled with care.
• Any fruit that has been affected by pests or disease, or are overripe should be
removed, as these items may spoil the rest of the packaged goods.
Root crops such as yam
• Tubers are graded for selling wholesale or retail.
• Yams can be processed into a powder for reconstituting into ‘instant yam’.
• Rejected tubers are sold as pig feed.
Leafy crop such as lettuce and vegetable flower crop such as cauliflower
• Heads are graded according to size.
• Heads are then packaged in clear polythene bags for selling wholesale
or retail.
Eggs
Figure 19.1 Crops, eggs and meat.
ITQ 3
Describe how a leafy crop should be
handled.
ITQ 4
Give a reason for why eggs are
placed with the larger (rounded)
end up.
270
• Eggs are fragile so care needs to be taken when handling them.
• Eggs are collected from nest boxes and battery cages and placed into an egg
basket. Care should be taken to prevent eggs from rolling, colliding and
cracking. The number of eggs collected is recorded each day.
• Eggs are then cleaned by simply wiping them with a damp cloth. They should
not be immersed in water as this destroys the protective coating on the
outside of the eggs.
• Eggs are graded according to colour, size, weight and level of damage. Grading
is necessary for quality control, consumer satisfaction and pricing.
• Graded eggs are packed into crates holding 6, 12 or 30 eggs, with their larger
ends uppermost to reduce pressure on the membrane and air space in the egg.
• The crates are the stored in a cool, clean room, free from unpleasant odours.
• Eggs are supplied wholesale to supermarkets and middlemen for pricing,
labelling and retailing to consumers.
Meat
• Sheep, goats, pigs and cattle are slaughtered at the appropriate age or weight
in an abattoir (slaughterhouse).
• Local laws ensure that the facilities are hygienic and humane so that animals
do not suffer undue stress.
• After slaughter, each carcass is bled, the hides removed and the internal
organs taken out. The carcasses are then chilled.
• Meat is inspected at the abattoir and stamped as fit for human consumption or
taken away for use as animal food or disposal by burial or burning.
• After slaughter, the meat has a period of ‘conditioning’ or ‘ageing’ during
which time it develops flavour as the muscles become tender.
• After ageing, the carcasses are cut into joints and cuts (described in Unit 25).
• Meat is marketed in different forms. It can be bought straight from the retailer
as a large joint, or it may be processed further into chops, steaks, mince or
cured meats.
19: Marketing of agricultural products
ITQ 5
State why vacuum packaging is
becoming more popular with the
consumer.
• The meat is then packaged using plastic film to control the atmosphere around
the meat, keeping the meat fresh and the colour attractive. The packaging also
protects the meat.
• Vacuum packaging is sometimes used for meat and meat products to extend
the life of the products. The atmosphere inside the pack contains less oxygen;
this prevents aerobic bacteria from reproducing and spoiling the meat.
19.4 The importance of international trade
agreements
If a country is to earn foreign currency, it needs to sell goods and services to
other countries. International trade agreements often involve goods and services
from one country being exchanged for the goods and services of another country.
Agreements have to be carefully set up.
The Caribbean Single Market and Economy (CSME)
Caribbean Community (CARICOM) ▶
Caribbean Single Market and
Economy (CSME)
CSME operations
removal of barriers to trade
free
movement
of goods
free
movement
of services
free
movement
of capital
free
movement
of people
Figure 19.2 The functions of the CSME.
In 2006, after considering the challenges of an increasingly globalised economy
and the need to increase competitiveness of its goods and services, the Caribbean
Community (CARICOM) set up the Caribbean Single Market and Economy
(CSME).
Member state
Antigua and Barbuda
Bahamas
Barbados
Belize
Dominica
Grenada
Guyana
Jamaica
St Kitts and Nevis
St Lucia
St Vincent and the Grenadines
Suriname
Trinidad and Tobago
Haiti
Montserrat
Table 19.4
CARICOM (full member)
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
CSME
✓
✘
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
By 2020
Participant
CARICOM and CSME membership.
The CSME (Figure 19.2) enables the free movement of goods, services, capital
and people across member states in the Caribbean. This means that production
and marketing operations are promoted and supported in an enlarged, single
economic area. There is a better environment for the competitive production of
goods and services for external markets and for markets within the region (intraregional markets).
271
Section D: The business of farming
Entrepreneurs in the CARICOM region are able to:
• use their talents and resources more fully
• trade freely between themselves without obstacles
• establish and service markets in other states
• attract capital or invest and use funds in another state
• hire skilled workers from any of the member states, resulting in greater
efficiency, competitive production and increased profits.
The removal of trade barriers and the opening up of new opportunities for
18 500 000 CARICOM nationals enables the CSME to stimulate growth.
Free movement of goods
To enable free movement, the following measures are enforced:
• there are no import duties on goods originating from the CARICOM region
• tariffs and quantitative restrictions have been removed in all member states
• intra-regional imports are treated differently from imports that come from
outside the region (extra-regional imports)
• there are agreed regional standards for the production of goods within the
CARICOM region, providing a major incentive for high-quality products from
producers and manufacturers.
Free movement of services
Member states are required to:
• remove barriers that restrict the right of any CARICOM national to provide
regional services
• ensure that nationals from other member states have access to land, buildings
and other factors of production on a non-discriminatory basis for the purpose
of providing services to the region.
Free movement of capital
Free movement of capital:
• enables CARICOM nationals to transfer money to any member state
electronically and also through bank notes and cheques; no new monetary
restrictions will be added and existing ones have been removed
• promotes and increases investment regionally
• gives firms access to a wider market for raising capital at competitive rates, so
enabling the productive sectors to become more competitive regionally and
internationally
• fosters the development of a regional capital market, which increases the
attractiveness of the region for investment.
ITQ 6
State the main role of the CSME.
Free movement of people
Free movement of people:
• promotes a closer union among the people of the CARICOM member states
• abolishes discrimination on grounds of nationality in all member states
• requires the removal of work permits for certain categories of workers
• encourages an interchange of managerial, professional and technical expertise
within the region
• enables certain categories of workers to travel freely to member states and
enjoy the same benefits and rights regarding conditions of employment as
those given to national workers.
The CSME is of particular importance in the agricultural sector because the
CSME makes it easier to market produce and secure investments, and it enables
workers to move freely. All the points made generally about the free movement
of goods, services, capital and people can be applied to any agricultural enterprise
or associated business.
272
19: Marketing of agricultural products
The World Trade Organization (WTO)
World Trade Organization (WTO) ▶
ITQ 7
State THREE functions of the WTO.
The World Trade Organization (WTO) is an international organisation that
promotes free trade by persuading countries to abolish tariffs on imports and
other barriers to trade. It is the only international body that oversees the rules of
international trade.
Functions of the WTO include:
• checking free trade agreements
• settling trade disputes between governments
• organising trade negotiations.
Decisions made by the WTO are final and all member countries must abide by its
rules. Any country that breaks the rules may have trade sanctions imposed on it.
As of 2019, there were 164 member countries.
New ACP-EU Partnership Agreement
(Cotonou Agreement) Economic
Partnership Agreement (EPA)
Features
• focuses on trade liberalisation and
globalisation: a global approach to
development
• provides for a new trade agreement,
covering a period of 20 years
• partnership agreement took effect
from 1 January 2008
• guided by the World Trade
Organization (WTO) rules
Role or function
• poverty eradication in ACP countries
• progressive insertion of ACP
countries into the world economy
Challenges
ACP countries must therefore:
• prepare themselves
• face competition on the international
market
• increase production, supply and the
competitive nature of their products
• maintain the desirable high standards
of quality and performance
• attract sound investment
Figure 19.3 The Cotonou Agreement – a
summary.
Since 2001, the WTO has been trying to negotiate a trade agreement that would
benefit poorer countries, but it has been hampered by disagreement between
exporters of agricultural commodities in bulk and countries with large numbers
of subsistence farmers. These countries want to ensure that there are safeguards
to protect farmers from a drop in prices or a surge in imports. In 2008, member
countries met in Geneva to resolve the problem, but the talks failed. Some critics
maintain that free trade only leads to the rich countries becoming richer and the
poorer ones poorer.
Free trade between Caribbean countries is now established, but better access to
world markets could benefit the economy of the region. The WTO is working to
encourage trade agreements that promote the economies of poorer countries.
Economic Partnership Agreement (EPA)
Economic Partnership Agreements (EPAs) are trade and development agreements
negotiated between the European Union (EU) and African, Caribbean and Pacific
(ACP) partners engaged in regional economic integration processes.
The EPAs
The promotion of EU and ACP trade will, through trade and investment, contribute
to sustainable development and poverty reduction. Trade with ACP countries
represents more than 5% of EU imports and exports. The EU is a major trading
partner for ACP countries. The EU is the main destination for agricultural and
transformed goods from ACP partners, but commodities (such as oil) still form a
large part of ACP–EU trade. The EPAs intend to support trade diversification by
shifting ACP countries’ reliance on commodities to higher-value products and
services. The EPA is a process dating back to the Cotonou Agreement of 1975,
Figure 19.3 summarises this.
The Cotonou Agreement aims to get rid of poverty in ACP countries and to
promote their entry into the world economy. To stop the poverty, ACP countries
need to:
• face up to the challenge of competition on the international market
• increase production, supply and the competitive nature of their products
• maintain high standards of quality and performance
• attract inward investment.
273
Section D: The business of farming
Duty-free rum, Grenada
The CARIFORUM–EU EPA means European visitors can return to the EU with authentic
Caribbean rum made from sugar cane. Tobacco can also enter the EU market duty- and
quota-free. There are restrictions for exporting alcohol that is over 70% alcohol by
volume (Alc / Vol) on aircraft due to the risk of the bottles exploding so Rivers Rum,
from the Antoine distillery, is banned from duty-free shopping in airports.
Most EU agricultural products face import tariffs in CARIFORUM countries.
The tariffs give local producers plenty of time to adjust to importexport trading.
Figure 19.4 Rivers Rum is
75% alcohol by volume.
Benefits of EPAs to Caribbean countries
These are the benefits of EPAs to Caribbean countries.
• Duty- and quota-free access for exports to the EU is possible.
• Regional markets are more integrated – boosting trade between neighbouring
ACP countries.
• ACP countries can avoid excessive competition because they can open their
markets to EU imports gradually.
• EPAs help deal with other trade and development issues, such as poor
infrastructure or time-consuming and difficult formalities at customs.
• EPAs support ACP countries, helping them to strengthen the rule of law,
attract local and foreign investment and create conditions for greater
prosperity.
• EPAs are stable partnerships between EU and ACP countries, who are equal
partners. The partnerships cannot be altered without mutual agreement.
ITQ 8
Describe TWO benefits of the EPA to
countries in the Caribbean.
Practical activity:
Working in groups, choose one
of the specific trade agreements.
Research this on the internet.
Design a poster that summarises
the agreement and its relevance to
trade in your country.
274
Caribbean Basin Initiative (CBI)
The trade programmes known collectively as the Caribbean Basin Initiative (CBI)
are important elements of the United States’ (US) economic relations with the
Caribbean. The CBI is intended to support the development of stable Caribbean
Basin economies by providing many Caribbean countries with duty-free access to
the US market for most goods. The CBI and related programmes include several
trade and aid initiatives with the US, signed in 1983 and later the United States–
Caribbean Basin Trade Partnership Act (CBTPA) of 2000 (this is set to expire in
2020).
Free Trade Agreements (FTAs) have a large impact on agricultural tariffs both for
the US and the Caribbean. For most of the countries with whom the US has FTAs,
exporters to the US will face zero tariffs on 98% of the agricultural goods, once
the agreements have had time to mature and be implemented fully.
19: Marketing of agricultural products
Revision map
Grading
Harvesting
Packing and
packaging
Agro- and
food
processing
Growing
Can trade
freely and establish
markets in other
states
Distribution
Planting
The removal of
trade barriers within the
Caribbean benefits the
Caribbean region
in international
markets
Advertising
Planning
Activities
involved
Sales
Market research
is gathering information
about consumer needs
and preferences
Market
segmentation splits
up a market into different
types (segments) to enable
a business to better target
its products to the
relevant customers
Agricultural
products marketed
within the
Caribbean
Meat
The Caribbean
Single Market and Economy
enables free movement of goods,
services, capital and people
across member states
in the Caribbean
Distribution
Assembling
Marketing
agricultural
products
Crops
Eggs
Marketing
of agricultural
products
Domestic market
is the market within
the country
Entrepreneurs
in the CARICOM
region
Trade
agreements are
set up to sell goods
and services to other
countries
Marketing
activities
Can invest
and use funds in
other states and hire
skilled labour from
any member
state
Marketing
steps
Pricing
Agricultural
products exported from
the Caribbean (sold to
different countries)
Cocoa
Sorting and
grading
Processing
Advertising
Storage
Labelling and
packaging
Transportation
Nutmeg
Rum
275
Section D: The business of farming
Examination-style questions
Multiple-choice questions
Write down the number of the question followed by the letter of the correct answer.
1.
2.
3.
4.
Which of the following is a benefit of market segmentation?
A Customer retention
B Fewer customers
C Fewer products
D More expensive products
Which of the following is NOT a step in the marketing of an agricultural product?
A Advertising
B Packaging
C Distribution
D Buying
Which of the following organisations make trade agreements only within the Caribbean
area?
A FTAA
B WTO
C CSME
D ISA
The abbreviation ACP stands for:
A America, Caribbean and Pacific
B Africa, Caribbean and Polynesia
C Asia, Caribbean and Pacific
D Africa, Caribbean and Pacific.
Short-answer and essay-type questions
5.
6.
7.
8.
9.
276
Describe the steps involved in marketing an agricultural product.
Using examples, explain the process of marketing agricultural products to a domestic
market.
Explain how being in the CARICOM region benefits entrepreneurs.
(a) Explain what is meant by a trade agreement.
(b) Evaluate how trade agreements benefit the Caribbean.
Describe the benefits of the Caribbean Single Market and Economy to the agricultural
sector.
Section E: Farm management technologies
20
Environmental
monitoring
By the end of this unit you should be able to:
✔ demonstrate the use of appropriate technology for the collection of
environmental data
✔ analyse environmental data
✔ apply environmental data to decision-making in crop and livestock
management
✔ demonstrate the use of appropriate technologies for conservation of
environmental resources.
Concept map
Precision agriculture
Soil
Moisture, pH, nutrients
Plants
Environmental monitoring
Decision-making using
environmental data
Greenhouse crops
Container gardens
Field crops
Intensive livestock
Extensive livestock
Leaf wetness, nutrients
Agrometeorology
Temperature
Rainfall
Humidity
Wind direction and speed
Analysing
environmental data
Nutrient monitoring
Variable rate N
Measures of central tendency
Measures of dispersion
Conservation of
environmental resources
Climate smart
agriculture
Soil
Nutrients
Careers
Agronomist / Extension officer
Precision agricultural engineer
Seed or chemical company adviser
Horticulturist
Greenhouse technician
Entrepreneurial
opportunities
Water
Rainwater harvesting
Organic mulches
Plastic mulches
Pasture
management
Overgrazing
Compaction
Drone technology
277
Section E: Farm management technologies
20.1 Using appropriate technology to collect
environmental data
ITQ 1
Why is environmental data collected
on farms?
Most agricultural activities have some effect on the environment. Environmental
monitoring allows us to assess the impact of these activities and determine whether
habitats or wildlife are threatened, or water or air is polluted. Governments
can use environmental monitoring to limit pollution. Farmers can also use
environmental monitoring to manage their farms in a way that does not harm
the environment. A number of substances used in farming, such as fertilisers,
pesticides and herbicides, can seriously damage the environment so farmers must
use these substances responsibly.
Precision agriculture
precision agriculture ▶
Figure 20.1 Weather station.
Precision agriculture (sometimes called satellite farming or site-specific crop
management) relies on data collected by satellite technology, remote sensing
devices and data-gathering technologies that are close to the aspects being
monitored. Precision agriculture is an information-based approach to making
decisions on a farm. It balances inputs of nutrients, pesticides, seeds or water
with the needs of different areas of the farm to improve productivity and resource
efficiency while also reducing costs and environmental impact.
Advantages of precision agriculture
• Soil and plants can be measured by sensors. For example, sensors can
measure nitrates, temperature, evapotranspiration, radiation and leaf and soil
moisture.
• Precise data can be obtained immediately. This tells the farmer about the
current state of the field and plants, helping him or her to make land
management decisions that will create the best conditions for plant growth.
• Precision agriculture saves money as the farmer will not need to use as much
fertiliser or as many chemicals, for example, pesticides.
• There is less environmental pollution from fertilisers and chemicals because
less is used in inputs.
• It results in more accurate farm records, which are essential for product sales,
selecting plant successions and managing crop rotations.
• More and more farm management software uses accurate precision farming
data to perform calculations to improve farm productivity.
• It results in reduced fuel use and less soil compaction from machinery
navigated by satellite technology.
• Crop management can be done at the best time, for example, spraying when
leaf moisture is at a suitable level.
• Profits are increased due to reduced costs and increased productivity.
Agrometeorology
agrometeorology ▶
ITQ 2
Explain why agrometeorology is
becoming more widely used in
farming.
278
Agrometeorology is the use of weather and climate data collection and
interpretation to support agricultural decisions, to increase food production,
and also to prevent damage to the environment. The ability to forecast the
weather (for example, hail, tornados and flash floods) up to 12 hours in advance
means that farming can make the best use of good weather. In the longer term,
agrometeorological information can be used to determine suitable crops for a
region, as well as perform a risk analysis of climate hazards and profit calculations,
production and harvest forecasts. It can also be used to select the most appropriate
farm machinery and methods for the location.
20: Environmental monitoring
ITQ 3
What are nutrient sensors and why
are they important in precision
agriculture?
Equipment
Maximum and minimum thermometer
Rain gauge
Dry and wet bulb hydrometer
Anemometer and wind vane
Leaf wetness sensor
Equipment used in environmental monitoring
There are a number of pieces of equipment used to monitor the environment.
Table 20.1 lists a selection of equipment and explains what the items measure and
how the data can be used.
What it measures
Maximum and minimum temperature of the air
throughout the day
Amount of rainfall in mm
Relative humidity of the atmosphere
Speed and direction of wind
Measures the percentage of time that a leaf
surface is wet, versus the percentage of time that
it is dry
Soil moisture sensor
Soil pH sensor
Volume of water in soil
pH of the soil
Nutrient sensor
Usually measures the nitrogen, phosphorus and
potassium levels; micro-nutrients can be measured
where necessary
How the data can be used
Influences planting decisions
Useful for spraying and harvesting decisions
Useful for making irrigation decisions
Useful for calculating spray drift
• Informs when the crop is most at risk of developing
certain diseases or infections
• Useful for determining whether the crop needs spraying
with insecticide, and the most appropriate timing
Useful for managing irrigation efficiently
Indicates the acidity / alkalinity of the soil so that the
farmer can correct it or select crops accordingly
• Useful for managing nutrients within individual fields
• Useful for understanding which variable is limiting the
growth of crops
• Useful for making fertiliser application decisions
Table 20.1 Equipment used in environmental monitoring.
20.2 Analysing environmental data
Descriptive statistics – discrete data
mean ▶
maximum ▶
minimum ▶
range ▶
mode ▶
median ▶
Discrete data is data that is based on counts. Using descriptive statistics is the simplest
method of summarising data. This makes the data clearer and easier to interpret.
• Mean: The average of a data set
• Maximum: The highest value
• Minimum: The lowest value
• Range: The difference between the maximum and minimum values
• Mode: The most frequently occurring number, group or class
• Median: The middle value when all the numbers are placed in ascending or
descending rank order
The following example about a citrus tree in Jamaica shows how descriptive
statistics can be used to summarise data about its productivity.
Day
Oranges
Day
Oranges
1
3
16
2
2
3
17
2
3
2
18
1
4
2
19
1
5
2
20
2
6
2
21
1
7
1
22
1
8
1
23
1
9
2
24
1
10
2
25
1
11
2
26
0
12
2
27
0
13
2
28
0
14
2
29
0
15
1
30
0
Table 20.2 The number of oranges a citrus tree in Jamaica produced during June.
Number of oranges
3
2
1
0
Frequency
Total
2
13
10
5
6
26
10
0
Table 20.3 How often each amount of oranges per day was produced (the frequency).
279
Section E: Farm management technologies
6 + 26 + 10 + 0
Mean daily harvest = ​ ____________
​
30
42
___
= ​  ​
30
= 1.4 oranges
So, the mean (average) daily harvest of oranges from this citrus tree in Jamaica
is 1.4 oranges.
To find the median daily harvest value, we arrange the data in ascending rank
order first.
0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3
The median is the middle value. As there is an even number of values, the median
is the average of the middle two values (15th and 16th values). The 15th value is
1 and the 16th value is 2, so the median is 1.5 oranges.
We can see from Table 20.3 that daily harvest value of 2 occurs most frequently,
so the mode is 2 oranges.
The maximum is 3 oranges. The beginning of the month of June had the highest
harvest of oranges.
The minimum is 0 oranges. Most of the fruit had been harvested from this citrus
tree by the end of June.
The range is 3, that is, 3 (highest value) – 0 (lowest value) = 3 oranges.
Measure of central tendency
Using descriptive techniques, most data can be summarised into some sort of
single ‘average’ value that can be used to describe the whole data set. This use of a
single value to represent a set of values is sometimes called a measure of central
tendency. The mean, median and mode are the most common measures of
central tendency.
measure of central tendency ▶
Measures of dispersion
It is often useful to show how far figures differ from the average. This is known
as measures of dispersion. The simplest way to show this is by using the range.
The range is the difference between the maximum and minimum values. The
range for citrus trees in Jamaica is very narrow because citrus trees in Jamaica
remain harvestable for nine months. An alternative measure of dispersion is the
inter-quartile range. This measure is similar to the range but is sometimes more
useful because it is not affected by extreme values.
measures of dispersion ▶
inter-quartile range ▶
Inter-quartile range
This measure of dispersion is found by first listing the data in rank order. The list is
then cut into four equal parts with three ‘cuts’. Each ‘cut’ is called a quartile (Q1,
Q2 and Q3). The 2nd cut, Q2, is the median and the inter-quartile range is Q3 – Q1.
In our example, we take our list of data in rank order and mark the quartiles that
divide it equally into four.
0
280
0
0
0
0
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2



Q1
Q2
Q3
2
2
2
2
2
3
3
20: Environmental monitoring
ITQ 4
What is the difference between
measures of central tendency and
measures of dispersion?
Where the quartiles lie between two data points the average of the two data
points is used.
Q1 = 1 Q2 = 1.5 Q3 = 2
The inter-quartile range is Q3 – Q1 = 2 – 1 = 1.
Nutrient monitoring – continuous data
Continuous data is data that is measured. New developments in combined sensor
and machinery technology allow the sensors to send the information from the field
directly to the tracking equipment in a tractor. The tractor uses the information
to control where to release the fertiliser or chemical spray. Using only what is
needed is good for an efficient farm business and it also reduces the amount of
chemical being introduced into the environment. Some tractors that have these
sensors are accurate to 1 cm.
It is useful to know how to describe this environmental data, so that the farmer
can interpret it too. Due to the areal extent of the data, it is often in the form
of contour map. The contour map in Figure 20.2 shows the phosphorus levels,
measured in parts per million (ppm), at 40 sensor locations in a one-hectare
field. Phosphorus is vital for healthy plant development, so it is usually applied
within fertiliser. A healthy phosphorus level in soil is between 20 and 30 ppm.
The purpose of such data is to increase the precision with which phosphorus
is applied to the field. Most farmers spread fertiliser throughout their fields.
However, this contour map shows that the farmer needs to apply phosphorus to
less than half the field. This information could save the farmer a lot of money. It is
also better for the environment because excess phosphorus can wash off the soil
into watercourses and cause eutrophication. (See Unit 3 for more information
and photographs of this environmental impact.)
Practical activities:
1. Use the colour classes from
the key and make a table to
show the frequency of each
sensor reading.
2. Put a red circle around the
sensors that are below the
healthy recommended level
for phosphorus.
3. Draw a dashed line on the map
to show where phosphorus
needs to be applied to achieve
at least 25 ppm throughout
the field.
N
20
23
28
33
36
39
42
48
21
22
25
28
33
38
40
43
17
20
25
27
32
35
37
41
18
22
24
26
26
29
32
33
19
21
22
23
25
27
28
30
Phosphorus in ppm
<45
39-44
32-38
25-31
22-25
18-21
>18
Figure 20.2 Contour map showing phosphorus levels in a field.
The data can also be presented as graphs (recorded in a specific location, but
changing over time) and in tables, to show raw data.
Variable rate
variable rate ▶
Nutrient monitoring prevents a farmer treating every field the same way. By
monitoring the nutrient level, a farmer can see which areas are deficient for that
nutrient and apply only the amount of nutrient needed in the areas that need
it for the specific crop. The farmer, therefore, applies the nutrient at a variable
rate. A number of different nutrients can be monitored before the application of
phosphate, potash, magnesium or lime. Variable rate application is most regularly
281
Section E: Farm management technologies
nitrogen ▶
ITQ 5
Describe how nutrients are
monitored remotely.
used with nitrogen, as this has a greater effect on crop growth, yield and quality
than any other nutrient. In addition, nitrogen levels are easier to measure than
other plant nutrients.
Variable rate nitrogen
Remote sensing technology includes optical sensors mounted on satellites. A
farmer can use this form of technology to identify and inspect variations in crop
canopy development. The farmer can then manage the crop using variable rate
applications of nitrogen.
N
31
29
28
27
28
28
27
26
30
28
27
26
25
25
24
24
27
26
25
24
23
21
18
18
26
26
24
24
22
19
17
15
19 a field.18
Figure 20.3 25Nitrogen 23
levels at 4020points across
16
16
15
Practical activities:
A farmer wants to plant a field
of corn. He has mapped nitrogen
levels at 40 points across the field
(see Figure 20.3) to see where he
should apply nitrogen, as corn
needs at least 25 ppm of nitrogen
to grow.
1. Using the data provided from
nitrogen sensors of the same
field, create a contour map and
colour it using a key.
2. Draw a dashed line to show
where nitrogen needs to
be applied.
3. Draw a table to show
the frequency of each
sensor reading.
What are the benefits of variable rate nitrogen?
• One way to assess the nitrogen levels within a crop is to measure the growing
crop canopy.
• Increasing nitrogen application can boost yields up to a point, but using more
than the crop needs is a waste of money.
• Excess nitrogen can cause an increase in problems such as lodging in sugar
cane. Lodging is the occurrence of weak stems that bend at ground level,
making harvesting difficult.
• Excess nitrogen may cause diseases that will result in a reduced yield.
• Excessive use of nitrogen increases the risk of nutrients leaching from the soil.
• Where there are higher nitrogen levels, more seeds can be planted and the
field will be more productive.
• Variable rate nitrogen application maps are produced that allow the farmer to
use the best nitrogen application rates based on the information acquired.
20.3 Applying environmental data to decisionmaking
Environmental management can be combined with commercial farming, when
decisions are made that benefit both the farming business and the local environment.
Decision-making is led by the environmental data that has been collected.
Greenhouse crops
Figure 20.4 Bell peppers in a greenhouse.
282
Greenhouses are used to provide growing spaces that have the best conditions
of light, temperature, water, nutrition and pest control for the plants. Within
the range of crops that are grown in greenhouses, there are variations in the
preferred quantities of light or nutrition. In its simplest form, a farmer who has a
thermometer inside his or her greenhouse may decide to put material up inside
the roof panes to create shade and cool the plants during the heat of the day.
20: Environmental monitoring
More complex, full-climate-control systems are available. These systems can be
programmed by computer to produce the best conditions and respond to live
data, making slight adjustments as the external weather conditions change.
Bivariate data
Bivariate data is data that has two variables, for example, the height of a plant and
the number of peppers it yields. Twelve plants had their height measured and the
number of peppers they had on them recorded on the same day (see Table 20.4).
This data was then plotted on a scatter diagram (see Figure 20.6).
Plant height (m)
Peppers
1.3
7
1.45 1.25
8
6
1.1
5
1.2
7
1.6
9
1.5
8
1.3
6
1.4
7
1.35
7
1.3
7
1.5
9
Table 20.4 The number of peppers on twelve plants on one day.
Number of peppers
10
9
8
7
6
5
4
Figure 20.5 Digital solar-powered
weather station with anemometer and
wind vane, rain gauge (cup), thermometer,
hydrometer, and leaf wetness and soil
temperature sensors. Fenced to prevent
grazing sheep damaging the sensor cables.
0
1.1
1.2 1.3
1.4
1.5
1.6
Height of plant (m)
Figure 20.6 Scatter diagram showing the relationship between the number of peppers
produced and the height of the pepper plant.
A line of best fit is a straight line on a scatter diagram that represents the best fit
with the points on the scatter diagram. It can show whether there seems to be a
relationship (also called a correlation) between the variables. It can be drawn by
positioning a straight line so that there is an equal number of plotted points above
and below the line.
ITQ 6
Using the graph in Figure 20.6,
estimate how many peppers might
be produced from a plant that is
1.7 m tall.
50
The line on this scatter diagram shows that there is a positive correlation
between the variables (number of peppers and plant height) because
the gradient, or slope, of the line of best fit is positive. It shows that, as
the height of the plant increases, the number of peppers also increases.
The reason for this is that, as the plant grows taller, there is more space
on the stem to develop buds, flowers and then fruit. However, there is
a maximum height for a plant. After this height, the plant will become
weak and the stem will be unable to support a higher number of peppers.
25
Other examples of data that might have a positive correlation are
amount of fertiliser and plant yield, and weight and age of a pig.
0
The line of best fit on the graph in Figure 20.7 shows a negative
correlation because its gradient is negative.
100
75
0
1
2
3
4
5
Figure 20.7 A negative correlation.
6
7
8
9
The age of a chicken towards the end of its life and the number of eggs
it lays could be an example of data with a negative correlation.
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Section E: Farm management technologies
Container gardens
container gardens ▶
Container gardens are increasing in popularity with our expanding population.
Information about the environmental conditions can help someone who wants to
grow plants in containers decide whether the environmental conditions already
available are suitable for the container garden planned or whether some adjustments
need to be made to create a good environment for the plants in the containers.
Applying environmental data collected will depend on what is being grown in the
containers. Containers are regularly used for shrubs that may need a loam-based
compost, as the heavier soil helps to support taller plants. Containers are useful
for growing shrubs and plants that would not thrive in the local soil, for example,
blueberries prefer acidic soils, so the plants would not grow well in limestone
soils. Containers are useful because they can be moved to get more sunlight, or
can be used to confine plants that spread quickly, such as mint.
Field crops
Figure 20.8 Irrigating a field of corn.
ITQ 7
Why is environmental data used to
make decisions relating to livestock?
Environmental data such as rainfall statistics can be used to determine when
irrigation is required. Knowledge about the nutrient content of the soil is also
useful for the farmer as he or she can add nutrients to the irrigation flow if the
nutrient level of the soil is low. If the farmer knows that slugs are a problem in
the environment, he or she can place slug traps around the field. A slug trap can
be a plastic sack held down by rocks. The environment underneath the plastic will
be damp, and these conditions suit slugs. If there are no slugs in these locations,
the farmer will not need to apply slug pellets. This will be a saving for the farmer
and for the environment too as slug pellets are poisonous. If the chemicals in the
pellets get into the rivers it will be very difficult to make the water safe to drink.
Practical activities:
The following table shows how many kilograms of 3% ferric phosphate slug pellets
were applied by farmers on ten one-hectare cornfields, and the number of slugs that
remained in each field (estimated from slug-trap data).
Pellets kg
Slugs (000s)
1
350
1.25
330
1.5
240
1.75
230
2
210
2.25
200
2.5
190
2.75
150
3
140
3.25
140
1. Plot a scatter diagram.
2. Draw the line of best fit.
3. Decide whether this is a positive or a negative correlation. Give reasons why you
have come to this conclusion.
Figure 20.9 Intensive livestock system (pigs).
Figure 20.10 Extensive livestock system
(goats).
284
Intensive livestock production systems
Livestock production systems place a lot of pressure on the environment as they
use large amounts of natural resources, such as land, water and fossil fuels, and
may release high volumes of pollution into the air, water and soil. Environmental
data supports decision-making by the farmer, who needs to ensure that the farm is
sustainably managed, balancing production against impacts on the environment,
while maintaining high standards of animal welfare. Precision livestock farming
quantifies the inputs and outputs, including the emission levels generated in the
farming process. It is possible to alter production systems, although reducing the
land used to house layer hens, for example, will compromise their welfare and
impact on them achieving their laying potential. Intensive industrialised livestock
20: Environmental monitoring
production systems separate livestock production from the land used to produce
feed. This results in a large concentration of waste products, which can put
pressure on the surrounding environment to absorb large quantities of animal
waste.
Extensive livestock production systems
Grazing and mixed farming systems tend to be closed systems, where waste
products of one production activity (manure, crop residues) is used as an input to
another production activity (fertiliser, feed). The environmental data in this case
will be needed to manage the timing of the inputs for each production system, as
well as the carrying capacity of the land, so there are not too many animals on the
land for the resources available. Water is a key resource for livestock. In extensive
systems, the animals drink a lot more water than in intensive systems. However,
intensive systems use more water overall due to cooling and cleaning facilities
and high concentrations of stock.
Figure 20.11 A dairy cow.
Practical activities:
A farmer has two dairy cows. The table shows the amount of milk, in litres, the farmer gets from each cow during April.
April
Cow A
Cow B
April
Cow A
Cow B
1
5
5
16
7
6
2
6
5
17
5
6
3
6
5
18
5
6
4
6
5
19
5
5
5
6
5
20
5
5
6
6
5
21
6
5
7
6
6
22
5
5
8
6
6
23
5
6
9
6
6
24
5
7
10
6
6
25
6
6
11
6
6
26
6
5
12
7
6
27
5
6
13
7
6
28
5
5
14
6
6
29
5
5
15
6
6
30
6
5
1. Find the mean, median and mode for milk production from each cow.
2. What do you notice about the values?
3. Suggest ways to increase the yield of both cows.
Calculating cattle feed
Sensors can be used to calculate precisely how much feed a fattening steer
requires. A steer is a neutered bull that is bred for meat. The purpose
of calculating the feed is to discover the most effective way to turn the
animal into quality meat. The aim of the calculation is to reduce the time
the animal is kept, and also to improve the quality of the feed. Sensors
are placed in tags in the ear. As the steer accesses the feeding trough, the
following data is recorded:
• the steer’s identification number
• the starting weight of the trough
• the ending weight of the trough.
Figure 20.12 Young steer feeding at the weightrough. Note the round sensor ear tag.
Other data can be collected as well, such as the time of feeding, the
amount of time the steer fed and which cow it followed to the feeding
trough. This is relayed back to a data logger. Through regular weight
checks, the farmer can use the data to decide on the best time to send
each animal to slaughter.
Figure 20.13 Livestock feeding trough with
sensor-operated scales.
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Section E: Farm management technologies
20.4 Use of appropriate technologies for
conservation of environmental resources
Climate smart agriculture
climate smart agriculture ▶
Climate smart agriculture (CSA) is an approach to help the people who
manage agricultural systems respond effectively to climate change. The CSA
approach pursues the three objectives: sustainable increase of productivity and
incomes, adaptation to climate change and reduction in greenhouse gas emissions
where possible. The term was first used by the Food and Agriculture Organization
of the United Nations (FAO).
Soil
A farmer can use a wide range of technologies to conserve soil, selecting the most
appropriate one for conservation. These technologies include crop rotation, strip
cropping, contour ploughing, shifting cultivation, using contour barriers, terrace
farming, intercropping, planting windbreaks or shelterbelts and afforestation.
These are discussed at length in Unit 5.
Figure 20.14 Eutrophication on a river.
Soil nutrients
Soil nutrients are easily leached from soil by the heavy rainfall that occurs in the
wet season. Lost nutrients need to be replaced as they are needed by the crop.
This can be expensive, and may also negatively affect the environment, causing
eutrophication, if the nutrients reach a river.
Water conservation strategies
Rainwater harvesting
Rainwater harvesting is the process in which tanks are used to hold the rainfall
that falls onto the roofs of buildings. The tanks have taps and the water in them
can be used for farming activities.
Organic mulch
This is where organic material, such as grass, is used to reduce the growth rate
of weeds and maintain soil moisture. The organic mulch is not removed after
harvest. Instead, it can be farrowed back and a new crop planted.
Figure 20.15 Grass mulch under lettuce.
Plastic mulch
Plastic is used to perform the same function as an organic mulch. Holes are made
in the plastic for the seedling and irrigation nozzle.
Pasture management
overgrazing ▶
compaction ▶
ITQ 8
Explain how water can be conserved
on farms.
286
During the dry season, there is a shortage of fodder. The grass is grazed to the
ground and torn out with the roots by animals (particularly cattle). This weakens
the top soil. Overgrazing can be avoided by creating separate grazing areas and
producing or buying larger quantities of fodder.
Soil compaction can be caused by machinery passing over a field and by animal
hooves. To manage compaction by animals, also called poaching, farmers put
hard standing in gateways and around drinking troughs and other bare soil areas,
until the grass can recover.
20: Environmental monitoring
Integrated approaches to production
Technology is used in soil, water, nutrient and pasture management to create
an integrated approach to production. Integration of different technologies to
conserve environmental resources will help the farmer use the natural resources
sustainably. It is important that the natural environment is managed in a
sustainable way. Using rainwater received in periods of high rainfall to irrigate
crops in dry weather is more sustainable for the environment than extracting
water from a river, which will be at its lowest flow in the dry season.
Adding nitrogen, even at a variable rate, is expensive and there is a limit to the
increase in yield. However, growing a leguminous cover crop to prevent bare soil
eroding from the farm and to fix atmospheric nitrogen into the soil has greater
benefits to the land and soil, as well as the future crop.
Mixed farming allows for the use of animal manure as a fertiliser for the crops.
Manure can also be used to provide energy by placing it into a biodigester to
generate gas.
Careers
ITQ 9
Describe the role of an extension
officer.
Agronomist / Extension officer
Agronomists and extension officers are agricultural advisors who look for ways to
increase soil productivity (in other words, to raise more food on the same amount
of soil). They also work to improve the quality of seed and the nutritional value
of crops. These advisors visit farmers to suggest alternative methods of working,
train farm employees and provide support to the farming community based on
research.
Precision agricultural engineer
This engineer fits the precision technology into tractors and sprayers and teaches
the farmer how to use the technology. These engineers also service and maintain
the equipment.
Seed / Chemical company advisor
These advisors are often qualified agronomists who are employed to advise on
the use of products that are produced by a seed or chemical company. They are
not independent and the advice they offer needs to be balanced by the farmer’s
knowledge and experience. For example, an advisor from a pesticide company
probably will not suggest using cultural techniques for pest management.
Horticulturalist
Horticulturalists are experts in garden cultivation and management. Scale (size)
is often considered to be the difference between farming and horticulture.
However, they also differ according to the techniques used and the plants grown.
Horticulturalists use data on plant growth statistics to make environmental and
care decisions relating to subsequent plants that will be grown.
Greenhouse technician
A greenhouse technician works in a greenhouse, and is in charge of transplanting,
thinning, harvesting, drying plants, and treating and watering seeds. They are
often also in charge of managing seed storage, such as labelling and categorising
seed envelopes with instructions for growth.
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Section E: Farm management technologies
Entrepreneurial opportunities
Precision farming offers many entrepreneurial opportunities, although ready-made
equipment is expensive. However, the Caribbean is ready for the development of
new technology based on sound agronomic principles. Once there is a method of
data retrieval in place, the data gathered can be interpreted usefully to increase
crop yields and quality. Profit and greater food security will follow. Even though
new technology is being developed all the time to solve agricultural problems,
new difficulties continue to emerge.
ITQ 10
Why is drone technology becoming
popular with farmers?
Drone technology
An agricultural drone is an unmanned aerial vehicle that is used in farming to help
increase crop production and monitor crop growth. Sensors and digital imaging
capabilities on the drones can give farmers a very clear picture of their fields.
This information may prove useful for improving crop yields and farm efficiency.
Drones are popular with farmers as they can be used as a problem-solving tool.
An accurate image of a field will show discolouration of the leaves, which may be
a fungus. This knowledge allows the farmer to treat that area of the crop. Drones
can also be used to monitor herds and flocks in remote areas. A small drone has a
range of around 1 km and three hours of flight time.
Figure 20.16 A drone in flight; the camera on the front can be seen clearly.
288
20: Environmental monitoring
Revision map
Reduces
costs
Improves
resource
efficiency
Reduces
environmental
impact
Risk analysis
of climate hazards
and profit
calculations
Precision
agriculture balances
inputs with the needs
of different areas
of the farm
Improves
productivity
Agrometeorology
is the use of weather
and climate data to
make agricultural
decisions
Environmental
monitoring assesses
impact of agricultural
activities
Water or
air polluted?
Production
and harvest
forecasts
Select
appropriate
farm machinery
and methods
Determine
suitable crops
Use of
technology
for collecting
environmental
data
Habitats
or wildlife
threatened?
Variable rate
technology involves
sensors working with tractors
to allow farmers to apply
nutrients in the right quantities
to only the areas that
need them
Analysing
environmental
data
Environmental data
can be summarised using
descriptive statistics to
make it clearer and easier
to interpret
Environmental
monitoring
Using
technology
to conserve
resources
Decision-making
using environmental
data from
sensors
Crops
Applications
Greenhouses
Livestock
production
Aims of the
CSA approach
Enables the
farmer to make
informed
decisions
Reduce
greenhouse gas
emissions
Technology is
used in soil-, water-,
nutrient- and
pasture-management
to create an integrated
approach to
production
Adapt
to climate
change
Sustainably
increase
productivity and
incomes
289
Section E: Farm management technologies
Examination-style questions
Multiple-choice questions
Write down the number of the question followed by the letter of the correct answer.
1.
2.
3.
4.
In agrometeorology, what would a nutrient sensor measure?
A Rainfall
B Temperature
C Nitrogen
D pH
In descriptive statistics, which of the following is a measure of dispersion?
A Mean
B Inter-quartile range
C Mode
D Maximum
Which of the following are soil conservation methods?
A Shifting cultivation, intercropping, planting windbreaks
B Spraying chemicals, ploughing, runoff
C Grafting, budding, planting seedlings
D Irrigation, harvesting, overgrazing
Which of the following statements about animal manure is true?
A Manure is used to roof houses.
B Manure is used to make paint.
C Manure is used as a windbreak.
D Manure is used to generate gas.
Short-answer and essay-type questions
5. Explain what precision agriculture is and how it will change farming.
6. State the tools used in agrometeorology and explain how these are used in farming.
7. Describe how environmental data can be used to improve container gardening.
8. Explain how water can be conserved on farms.
9. Explain how good pasture management can reduce soil erosion.
10. (a) Describe how sensors can be used in farming.
(b) Explain the benefits of using sensor technology in food production.
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Section E: Farm management technologies
21
Nursery
management
technologies
By the end of this unit you should be able to:
✔ demonstrate the preparation of compost using suitable materials
✔ prepare appropriate propagation and growing media for seedlings and
✔
✔
✔
✔
Concept map
vegetatively propagated crops
demonstrate proper handling procedures for different types of media
assess seed quality
recommend suitable seed storage procedures
demonstrate proper procedures and choice of equipment for establishing
plants in a nursery.
Nursery management technologies
Making compost
Propagating
Compost tea
Assessing seed quality
Ornamental crops
Sterilising media
Handling
procedures
Turf grass
Using seed
Using sod
Sprigs
Plugs
Organic
Peat
Wood residues
Bagasse
Organic materials
Inorganic
Sand
Perlite
Vermiculite
Calcined clays
Expanded polystyrene
Urea formaldehydes
Nursery careers
Horticulturist
Greenhouse
technician
Nursey worker
Sampling
Purity test
Number of seeds per
unit weight
Viability test
Germination test
Seed vigour test
Seed storage procedures
Vegetables
Fruit crops
Citrus
Mango
Avocado
Golden apple
Root and tuber crops
Process of tissue culture
Opportunities for
entrepreneurship
Nursery equipment
Dibber
Garden trowel
Hand fork
Cultivator (hand rake)
Weeding (patio) knife
Garden transplanter
Use of growth regulators
Cytokinin
Auxin
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Section E: Farm management technologies
21.1 Preparation of compost
composting ▶
Composting refers to the process by which organic matter (leaves, soft stems,
rejected fruits and vegetables) is decomposed to form compost manure that
is added to plants to provide nutrients for growth. When making compost,
several essential components are needed and each one has a specific function
(see Table 21.1).
Material or component
Organic matter: leaves, soft stems,
rejected fruits, vegetables and peelings
Starter: pen manure or compost manure
Sulphate of ammonia
Ground limestone
Water
Function in the composting process
Undergoes decomposition by micro-organisms to form
compost manure.
Adds micro-organisms (decomposers) to the compost
heap.
Supplies nitrogen, which enables the micro-organisms to
multiply and increase their population.
Provides a suitable pH within the compost environment
to encourage rapid microbial activity.
Provides moisture for a humid environment to help
microbial activity.
Table 21.1 Composting materials and their functions.
Making compost
To prepare compost, a suitable site needs to be chosen. It should be well drained
and close to the garden or cropping area. The base of the composting area should be
concrete and measure 4 m long × 1.5 m wide. Instead of concrete, plastic sheeting
could be securely pinned to the ground. It is usual to divide the composting area
into three equal compartments, each approximately 1.3 m wide and 1.5 m long.
Phase 1 section
Phase 2 section
Phase 3 section
storage shed with
compost manure
concrete base
Figure 21.1 The composting area.
The Phase 3 section needs a protective cover to prevent loss of nutrients through
runoff and leaching. A shed is useful for storing composted material and to protect
it from rain.
ITQ 1
Describe what composting is and
why it is needed.
292
When construction of the composting area has been completed, all composting
materials should be collected and sorted. All bottles, plastic containers, stones
and tin cans need to be removed. Plants with hard woody stems are difficult to
compost and it is a good idea to remove nut grass and weed plants with seeds.
21: Nursery management technologies
The Phase 1 section is then built up in the following way.
• A layer of starter material consisting of pen manure is placed on the base, to a
depth of 10 cm.
• A layer of organic matter is loosely arranged on top of the starter and built
up to about 25 cm in thickness. Both the starter layer and the organic matter
need to be loosely arranged to allow air to circulate.
• Next, 1 kg of sulphate of ammonia is broadcast over the organic matter layer.
• Then 0.5 kg of ground limestone is spread evenly on top of this.
• Alternate layers of starter and organic material (plus the fertiliser and
limestone) are stacked until a height of 1.5 m to 2 m is reached.
• The heap is watered and kept loose and moist.
Figure 21.2 Composting area, Sugar Cane
Feeds Centre, Trinidad.
ITQ 2
Make a list of the materials that
need to be removed from waste
before it is composted.
ITQ 3
Explain why limestone is added to
the compost heap.
After 3 to 4 weeks, all the materials in the Phase 1 section are transferred to the
Phase 2 section, making sure that any undecomposed materials that were at the
bottom and sides of the old heap are placed in the middle of the new heap. A
suitable moisture level is maintained by watering when necessary. The compost is
left in the Phase 2 section for a further 3 to 4 weeks. After that time, it is moved
to the Phase 3 section. The compost is left to decompose here for another 3 to 4
weeks. At the end of this period, the compost is transferred to the storage area and
is ready to be used on the garden or cropping area.
During the decomposition of organic material, microbial activity results in high
temperatures that destroy parasitic organisms and some of the weed seeds in the
plant wastes.
Once the material has been moved out of the Phase 1 section, a new heap can be
built up in this section, following the same sequence. In this way, the farmer has
a continuous supply of compost to maintain soil fertility.
Practical activity:
The composting process described here is suitable for situations where there is a
lot of vegetable waste and the farmer has a large enough area on which to build
a site and storage area. Smaller farmers and gardeners may use specially designed
plastic bins, which take up less space.
Prepare compost following the
guidelines given.
The instructions for making compost tea can be found in Unit 22.
Compost research at the
Sugar Cane Feeds Centre,
Trinidad
Wet grass will compost more quickly than dry plant material.
Leachate, the fluid that is produced by the decomposition of the
grass, is rich in microbes. The photograph here is compost that
was produced in only two months. It is a fine-grained,
light organic material. The Centre packages their
compost and sells it to the public.
Figure 21.3
Trinidad.
Compost in hand, Sugar Cane Feeds Centre,
293
Section E: Farm management technologies
21.2 Prepare propagation and growing media
Sterilise propagation and growing media
rooting cuttings ▶
Rooting cuttings allow a grower to rapidly multiply the numbers of a range
of herbaceous and woody plants. It is important for root development and plant
growth to take and prepare cuttings properly, using an appropriate container and
rooting medium. It is also important to provide the cuttings with good care. Soil
that was previously used to grow plants, root cuttings or start seeds, could contain
weed seeds, fungal pathogens and pests that can prevent the development of
healthy new plants from cuttings. Heating the rooting medium appropriately can
kill problematic organisms, effectively sterilising the soil. Sterilisation is important
for plain soil, soil blends or completely soil-less mixes that have previously been
used to start or support plants or were in contact with organic waste.
ITQ 5
Follow these steps to sterilise soil.
1. Fill an oven-safe baking dish with an even layer of soil no more than 10
cm deep. Any type of soil can be heated for sterilisation, although heating is
not necessary for new, inorganic materials such as perlite or vermiculite or
previously unused organic materials labelled as pasteurised or sterilised.
2. If the soil does not already feel slightly damp to the touch, moisten the soil
lightly. Either spray a mist of water over the soil or pour a small amount of
water onto the soil and mix it in.
3. Cover the soil and container tightly with aluminium foil so that the soil keeps
its moisture. Push an oven-safe thermometer through the foil into the soil in
the centre of the dish.
4. Place the dish of soil in an oven heated to 80 – 90 °C.
5. Monitor the temperature of the soil. Note when the soil temperature reaches
80 °C. To destroy organisms, keep the soil at or above this temperature for
at least 30 minutes. The soil must not go above 90 °C, as this can produce
substances that are toxic to plants.
6. Allow the soil to cool before transferring it to containers or a garden bed or
placing cuttings in the soil. Keep the aluminium foil in place until you are
ready to use the soil.
When soil is heated during the
preparation of growing media, why
must it stay below 90 °C?
Thoroughly clean the tools you will use to take the cuttings and the containers
you will plant them in.
Figure 21.4 Guava cuttings in pots.
ITQ 4
Explain why soil is sterilised before
growing root cuttings or seedlings
in it.
Ornamental crops
Heliconias, orchids, ginger lilies, Anthuriums and roses are cultivated in the
Caribbean. Most are marketed locally but some are exported.
Figure 21.5 Ornamental crop
(Ginger lily).
294
Propagation
• Heliconia: Offshoots or rhizomes are divided into clumps (2–3 shoots) or
setts (10 –15 cm)
• Ginger lily: Offshoots or rhizomes as for Heliconia; or plantlets from old
blooms propagated in individual containers each with 2–3 plantlets
• Anthurium: Offshoots or suckers from the mother plant; rooted tops of old
plants (cuttings); plantlets propagated by tissue culture; seedlings (hybrids)
propagated in a nursery
• Orchids: Plantlets; offshoots
• Roses: Cuttings
21: Nursery management technologies
Turf grass
The following grass species are often used in the establishment of lawns, golf
courses and games pitches.
• Bermuda grass (Cynodon dactylon) – green couch grass
• Savanna grass (Axonopus compressus) – sometimes known as broad-leaved
carpet grass
• Manila grass (Zoysia matrella)
You can establish lawns from seeds or by using sod (sprigs or plugs) once the
soil has been prepared. The land should be cleared, dug over or ploughed, and
rotovated to produce a seedbed. The soil is then graded, smoothed and levelled.
The plot is left to allow weed seeds to germinate. The weeds can be removed
by hand or sprayed with a herbicide. Lime and fertiliser are then added and
incorporated into the soil before planting.
Figure 21.6 Bermuda grass.
Using seed
Grass seed should be bought from a reputable supplier, should be of good quality
and should have a high percentage germination rate. It can be spread by hand or
by using a mechanical drill or spreader. If fertiliser has not already been added
to the soil, it can be mixed with seed before sowing. The seed should be spread
evenly to ensure a good cover.
The quantity of seed needed can be calculated by finding out the area of the
lawn and following the guidelines given by the seed supplier. For example,
Bermuda grass is sown at the rate of 30 – 60 kg / ha (3–6 g / m2) and Savanna grass
at 20 – 60 kg / ha (2–6 g / m2). A high sowing rate will prevent weed development
during the early stages of growth.
Using sod
The quickest way to establish a lawn is to use sod, or turf, but this method is also
the most expensive way. Sod is often used for landscaping or for small areas of
lawn. The ground needs to be prepared, graded and levelled and the sod watered
frequently until the lawn has established itself.
sprigs ▶
Sprigs are pieces of sod containing a stolon and roots. They are sometimes called
runners. The area needs to be prepared in the same way as a seedbed, although
the tilth does not need to be as fine. The area should be weed-free. The density
of planting may be low or high, but the higher the density, the more quickly the
ground will be covered in lawn. Sprigs can be planted 15–20 cm apart or broadcast
over the soil, followed by raking to chop and incorporate previous crop residue
into the soil and partially cover the sprigs with soil. Sprigs can be purchased or
turf can be bought and then shredded to form the sprigs. A lawn planted in this
way will establish itself more quickly than a lawn grown from seed.
plugs ▶
For fine-leaved species of grass, plugs are used instead of runners. A plug is a
small piece of sod that is 5 cm across. It is made by cutting up sod and it contains
shoots, roots and soil. One effective way to establish lawn is to chop up runners or
sod, mix the result with soil or peat and then spread the mixture over the surface
of the area.
ITQ 6
Describe how turf grass is established.
Vegetables
Vegetables are grown from seed or from tissue cultures (micropropagation).
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Section E: Farm management technologies
Fruit crops
Citrus (Citrus genus)
Citrus plants are propagated by budding and then planting out when the plants
are a year old.
Mango (Mangifera indica)
Mango plants can be grown from seed, with the seedlings raised in a shaded
nursery. If specific varieties are required, these varieties can be grafted on to
healthy rootstock during the first year of growth.
Avocado (Persea americana)
Avocado plants can be grown from seed but the farmer will need to wait 4–6 years
before the trees bear fruit. For this reason, grafting is the usual way to propagate
avocado plants. Grafting also maintains quality and yield of fruit. Rootstocks can
be propagated by seed or by layering. Year-old scions are grafted on to rootstocks
and left for 6–12 months before being planting out.
Golden apple / June plum (Spondias cytherea)
Scions from tall golden apple trees are grafted onto dwarf rootstocks. This method
ensures large fruit size and scions that are free from disease.
Figure 21.7 Citrus trees.
Figure 21.8 Mango tree bearing
fruit.
Figure 21.9 Tall golden apple tree that
has been grafted, CARDI, Grenada.
Root and tuber crops (tissue culture)
Root crops such as potatoes and tubers such as cassava are often grown from
tissue culture to prevent viruses and fungi that are present in the soil being passed
on to a new crop.
tissue culture ▶
growth medium ▶
agar ▶
296
Tissue culture is a process used to create new plants. In the process, a small
piece of plant tissue is taken from a plant and placed in a solution that contains
nutrients and hormones that will help the tissue grow into a plantlet quickly. The
solution used is called culture solution or growth medium.
In this process, the growth medium or culture solution is very important as it
contains various plant nutrients in the form of ‘jelly’ known as agar as well as plant
hormones that are necessary for the growth of the plant. The plants produced from
tissue culture are genetically identical to the parent plant that provided the tissue.
21: Nursery management technologies
callus ▶
The process of tissue culture has the following steps.
1. A small piece of plant tissue is taken from the growing point of a plant or from
the tip of the plant and placed on a sterile jelly that contains nutrients and
plant hormones.
2. The hormones make the cells in the plant tissue divide rapidly, producing
many cells that form a shapeless lump called a callus.
3. The callus is then transferred to another jelly containing plant hormones that
will stimulate it to develop roots.
4. The callus with roots is moved to another jelly containing different hormones
that will stimulate the development of shoots.
5. The callus, having roots and shoots now, separates into tiny plantlets. In this
way, many tiny plantlets are produced from just a few original plant cells
or tissue.
21.3 Proper handling procedures for different
types of media
Growing media are the different materials in which plants are grown. Growing
media are specifically designed to support plant growth and they can be either
solids or liquids. Different components are blended to create homemade and
commercial growing media. Different types of growing media are used to cultivate
different plants. The composition of a growing medium should be determined by
the crop being produced.
These are the growing media readily available in the Caribbean.
Peat and peat-like materials
Peat moss is formed by the accumulation of plant materials in poorly drained
areas. The type of plant material and the amount of decomposition present play a
large part in determining the material’s value for use in a growing medium.
Figure 21.10 Peat.
Wood residues, including leaf mould, bark and sawdust
Wood residues constitute a large source of soil-less growing media. These materials
are generally by-products of the timber industry and are readily available in large
quantities. One of the primary problems associated with these materials is the
nitrogen depletion by soil micro-organisms, which occurs during the decomposition
process. However, applying nitrogen supplements to the growing media can fix
this problem.
Bagasse
Bagasse is a waste product of the sugar industry and is readily
available at low cost. It may be shredded and / or composted
to produce a material that can increase the aeration and
drainage properties of container media. However, because
of the high sugar content in bagasse, rapid microbial activity
occurs after the bagasse is incorporated into a medium, and
this makes the use of bagasse of limited value.
Figure 21.11 Bagasse at a rum distillery, Grenada.
Organic materials
Rice hulls (husks) are a by-product of the rice milling
industry. Although they are extremely light in weight, rice
hulls improve drainage well. The particle size and resistance
to decomposition of rice hulls and sawdust are similar.
Manures, corn cobs, straw and nutmeg shells can also be
used as growing media.
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Inorganic growing media
Inorganic growing media are generally used to increase the number of large pores,
decrease water-holding capacity and improve drainage and aeration in growing
media. Other materials such as pumice, cinders and pea-gravel are also suitable
for this.
Sand
Sand, a basic component of soil, ranges in particle size from 0.05 mm to 2 mm in
diameter. Medium and coarse sand particles improve media texture and drainage.
Although sand is generally the least expensive of all inorganic amendments, it is
also the heaviest, which may result in high transportation costs. Sand is a valuable
amendment for both potting and propagation media.
perlite ▶
vermiculite ▶
Perlite
Perlite is a siliceous volcanic mineral. The grades used in container media are
first crushed and then heated until the vaporisation of combined water expands
it to a light powdery substance. Lightness and uniformity make perlite useful
for increasing aeration and drainage. Although costs are moderate, perlite is an
effective amendment for growing media.
Vermiculite
Vermiculite is produced by heating a micaceous mineral to approximately
745 °C. The expanded, plate-like particles that are formed have a very high
water-holding capacity and aid in aeration and drainage. Vermiculite also supplies
potassium and magnesium.
Calcined clays
Calcined clays are formed by heating montmorillonite clay minerals to approximately
690 °C. The pottery-like particles formed are six times as heavy as perlite and very
durable. Calcined clays have a relatively high water-holding capacity.
Expanded polystyrene
Polystyrene flakes, a by-product of polystyrene processing, are highly resistant
to decomposition, increase aeration and drainage, and decrease bulk density.
Polystyrene may be broken down by high temperatures and by certain chemical
disinfecting agents.
urea formaldehyde ▶
Urea formaldehydes
Urea formaldehyde is a transparent thermosetting resin. This material is prepared
by mixing air with a liquid resin and allowing to cool. Urea formaldehyde foams
have a greater water holding capacity than polystyrene but are similar in their
influence on aeration and drainage. The raw materials are easily transported.
Preparing soil-less growing media
Preparing soil-less growing media should result in a medium with the following
characteristics:
• porous and well drained, yet retaining some moisture, between irrigations
• relatively low in soluble salts, but with an adequate exchange capacity to
supply the elements necessary for plant growth
• standardised and uniform with each batch to permit the use of standardised
fertilisation and irrigation for each successive crop
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ITQ 7
State FOUR growing media that are
used in the Caribbean.
• free from harmful soil pests, pathogenic organisms, soil insects, nematodes
and weed seeds
• biologically and chemically stable following pasteurisation; primarily free from
organic matter that releases ammonia when it is subjected to heat or chemical
treatments.
Ratio
2:1
3:1:1
2:1:1
3:1:1
Components
Peat / perlite
Peat / perlite / vermiculite
Peat / bark / sand
Bagasse / bark / sand
Table 21.2 Commonly used soil-less mixtures for greenhouse crops.
Practical activities:
1. Mix a soil-less medium and use it to grow a range of seedlings.
2. Assess the quality of a seedlot by performing quality tests. Follow the information
in Section 21.4 to work out what the purity of the seedlot is (determine the pure
seed percentage and the percentage of undesirable grass seeds) as well as test
the viability of the seeds.
21.4 Assess seed quality
The physical quality of the seed should be assessed before the seed is stored or sown.
This is especially important if seed is to be stored for a long time before sowing.
Seed-quality tests can be done to check seed purity, viability and germination.
Sampling
If a large volume of seed needs to be tested, the seed must be mixed thoroughly
first before samples of seed are taken for quality assessment. At least two samples
should be used in each quality test, so that the results can be analysed, compared
and evaluated.
Purity test
Seed is considered pure if it appears normal in terms of size, shape and general
outward appearance. Seed that is too small, has been partly eaten by insects or
shows fungal stains is regarded as impure. To measure the purity of the seed
sample, pure seed is separated from impure seed and then the two groups are
weighed separately. A sample for a purity test may consist of 100 to 1 000 seeds.
The purity percentage is calculated as follows:
Weight of pure seed
____________________
Purity percentage =
​    ​× 100
total weight of sample
Advantages
Simple to perform
Easy to interpret and understand
Disadvantages
Subjectivity (personal opinion) is involved when
separating the seeds
Different reasons for impurity
Table 21.3 Advantages and disadvantages of the purity test.
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Number of seeds per unit weight
It is important to know the number of seeds per unit weight in a seed collection,
because this number and the germinative energy percentage can be used to
calculate the approximate weight of seed required to produce a desired number
of seedlings.
To determine the number of seeds per unit weight, two or more random samples
of, for example, 100 grams are taken from the seedlot. The number and weight
of pure, full seeds are then obtained. As in the purity test, impure seed is rejected
and all other included.
The number of pure seeds per kilogram can easily be calculated as:
Number of pure seeds in sample
​× 1 000
​ _____________________________
Grams of pure seeds in sample
Viability test
The viability of a seedlot, as well as the maximum possible germination to be
expected, are indicated by the results of a viability test.
Conducting a viability test
1. Remove a sample of 100 (or a multiple of 100) pure, full seeds from the
seedlot.
2. Open each seed by cutting it in half with a knife, or crushing the seed coat
with a small hammer.
3. Inspect and record the number of seeds with a healthy, well developed and
full endosperm and embryo. (A hand lens is useful here.)
A full seed percentage is calculated as:
Number of healthy well developed, full seeds
​× 100
​ _________________________________________
Total number of seeds in sample
Germination test
Often, full seeds that appear sound will not germinate because they were not
fertilised or are too old. Therefore, the most reliable way to assess the quality of a
seed collection is to actually germinate a sample of seeds.
To determine the germination percentage, random samples of seed are tested by
subjecting them to favourable germination conditions. A germination test can be
made in sterile containers, that is, pots or tins used in nurseries, or in a simple
covered Petri dish. A variety of germination media are acceptable for a germination
test, although the one used must properly aerate and moisten each seed.
A temperature of 30 °C for 16 hours (day) and 20 °C for 8 hours (night) during
a germination test is prescribed by the International Rules for Seed Testing
(ISTA 2019). These rules also specify exposure of the seeds to light during a test.
Samples of seed need to be large enough to ensure that at least a few of the
seeds will germinate. Until the end of the active germination period, the number
of seeds that have normal germination should be recorded at regular intervals.
Once a seed has germinated and been counted, it should be removed to avoid
accidentally being counted again.
The results of a germination test can be expressed in different ways, including
germination percentage, germinative energy, and germination capacity.
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germination percentage ▶
germination energy ▶
energy period ▶
germination capacity ▶
ITQ 8
Describe when a germination test
should be used.
Germination percentage
Germination percentage, or the actual percentage of the total number of seeds
in the sample that germinated during a test, is useful in comparing the quality of
seed collections for testing programs and in research.
Germination energy
Germination energy refers to the percentage of seed in the sample that has
germinated in a test up to the time when the number of seeds germinating per
day reaches its peak. The number of days required to reach this peak is the energy
period. In general, seedlings that originate from seed that germinates within the
energy period make the best quality planting stock.
Germination capacity
Germination capacity is the total number of seeds in the sample that have
germinated in a test, plus the number of seeds remaining ungerminated but still
sound at the end of the test. This is shown as a percentage.
The results of a germination test are often used to calculate the quantity of seed
that must be sown to obtain a given number of seedlings. However, it must
be remembered that the actual number of surviving seedlings is likely to be
much smaller than indicated by the germination test, because of losses due to
unfavourable weather, rodents and birds, insects and diseases.
Seed vigour tests
Seed vigour can be considered the closest measure of potential field performance.
For seedlings classified as normal by a germination test, there will in fact be
differences between the seedlings in their ability to perform well under a wide range
of environmental conditions. Vigour tests aim to measure the ability of the seed to
perform well under unfavourable conditions and are used for two main reasons:
• To discriminate between seedlots for suitability for storage.
• To discriminate between seedlots for planting value in relation to optimising
establishment (for example, to maximise performance under sub-optimal
seedbed conditions).
It is more economical for a large company to send off seed samples to have a seed
vigour test done in a specialised laboratory.
21.5 Suitable seed storage procedures
Storage starts when the mother plant attains physiological maturity. After harvesting,
the seeds are either stored in warehouses, in transit or in retail shops. Introduction
of high yielding varieties and hybrids, along with the modernisation of agriculture
has made it necessary to develop storage techniques to preserve the seeds.
seed viability ▶
Seed storage is the preservation of seeds under controlled environmental conditions
that maintain seed viability for long periods. Seed viability is the ability of a seed
to germinate and produce a plant under the correct conditions. The longevity of
seeds depends on initial seed quality, moisture content and temperature during
storage. In general, low moisture content and low temperature reduce the loss of
seed viability.
Different combinations of moisture content and temperature can be used to
prolong seed viability during storage.
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Seed storage
This should be low moisture content and low temperatures, though refrigeration
costs may be an issue. Ideally, seeds should be kept in a cold storage facility, such
as a fridge. Larger businesses will use a walk-in cold store. The boxes of seeds
should be clearly labelled and if more than one cold store is used, there should
be a reference guide so that staff know where to find the correct seeds. This is
particularly important if more than one species of the same crop is being stored,
and the species have different pH or soil preferences.
ITQ 9
Describe the conditions that are
ideal for seed storage.
The most important part of seed storage is that the seeds are dry and containers
are water and air tight. A moisture removing material (like silica gel) should be in
the container as this will prevent existing moisture from rotting the seeds.
21.6 Proper procedures and choice of equipment
for establishing plants in a nursery
Establishing plants in nurseries requires tools to help perform delicate tasks
with seedlings.
dibber ▶
garden trowel ▶
hand fork ▶
cultivator or garden hand rake ▶
weeding or patio knife ▶
302
Dibber
A dibber is a pointed wooden stick for making holes in the ground so that seeds,
seedlings or small bulbs can be planted in the hole. Dibbers can have handles
with different shapes (T-bar, L-shape and straight). A stick can be used in place of
a straight dibber.
Garden trowel
A garden trowel is a small hand tool used for digging, applying, smoothing and
moving soil.
Hand fork
A hand fork usually has three sharp, sturdy prongs and a wooden, plastic or
metal handle. Hand forks are used for a variety of gardening tasks, including
aerating and cultivating soil, light weeding and transplanting seedlings. As a result
of its small size, the tool is especially useful when working in confined spaces,
such as containers, borders or closely planted beds.
Cultivator or garden hand rake
A cultivator or garden hand rake is often used in place of a garden rake when
working close to the surface of small areas, such as borders or planting beds.
Garden hand rakes can be used to turn and till soil. They are especially useful
for doing this around plants in pots and flowerbeds, as the small head means the
tool is easy to move around in smaller spaces. Because the prongs of garden hand
rakes are usually fairly strong, they can be used for digging into soil to remove
weeds and other unwanted materials. Some of these hand rakes should also be
strong enough to disturb the surface layer of soil and move dead plants, as long as
the plants are not too deep set or woody.
Weeding or patio knife
A weeding or patio knife makes it easier to get the grass out from between
paving slabs or anywhere with narrow crevices where weeds can take root. This
knife can also be used to remove little stones and pebbles caught in the space.
They are handy tools for digging and cutting out roots, weeds and other unwanted
items wedged in tight spaces.
21: Nursery management technologies
garden transplanter ▶
watering can ▶
Garden transplanter
A garden transplanter is a narrow trowel that is used for more precise work. It
has measurements along the tool that can be used to plant bulbs at specific depths.
Watering can
A watering can is a container with a handle and a spout. The spout is used to
deliver water to the upper surfaces of the plants. The spout can be fitted with
different ‘roses’, which vary in the size of holes through which the water will
flow. The hole size is chosen for the rate of application of the water and the
delicacy of the seedlings that need to be watered. Chemical products that need to
be diluted can be added to the water in the watering can, for example, insecticides
and phosphorus plant growth boosters. However, the watering can must be triple
rinsed following the application of a chemical.
Figure 21.12 Garden trowel, hand fork and transplanter (left); watering can (right).
ITQ 10
Use of growth regulators
Explain what a plant growth
regulator is and why it is used
in nurseries.
Plant growth regulators (PGRs) are molecules that influence the development
of plants and are generally active at very low concentrations. There are natural
regulators, which are produced by the plant itself, and synthetic regulators. The
regulators that are found naturally in plants are called phytohormones or plant
hormones. PGRs are used in nurseries to make the plants grow quickly so that
profits can be maximised.
cytokinins ▶
auxin ▶
Cytokinins
Cytokinins are plant hormones that cause increased cell division by stimulating
the process of mitosis. They are made naturally by plants but biologists have
developed artificial cytokinins too. Increased mitosis results in plant growth and
the formation of shoots and buds, as well as the development of fruits and seeds.
Auxin
Auxin is a plant hormone produced in the stem tip. It promotes cell elongation.
Auxin moves to the darker side of the plant, causing the cells there to grow larger
than corresponding cells on the lighter side of the plant.
Careers
Horticulturist
A horticulturist is an expert in garden cultivation and plant management. They
plan nursery planting and landscaping, plant propagation, crop production and
plant breeding.
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Section E: Farm management technologies
Greenhouse technician
A greenhouse technician is in charge of transplanting, thinning, harvesting, drying
plants, and treating and watering seeds. They are often in charge of managing
seed storage and are responsible for labelling and categorising seed envelopes with
instructions for growth. Greenhouse technicians collect data by keeping records
of plant growth statistics and make environmental and care decisions based on
that data.
Nursery worker
Nursery workers grow plants in the nursery and also advise customers on which
plants to buy. Sometimes this role includes delivering plants to customers’ homes.
Opportunities for entrepreneurship
A nursery business is one of the easiest businesses to set up and begin to make a
profit. However, it is hard work and the plants will require careful attention.
• You will need a business plan in order to obtain permits and any loans that
are required for equipment.
• Do initial checks for available land where greenhouses can be built, and
where there is access to water for irrigation.
• It will be necessary to visit the Ministry of Agriculture to obtain business
permits, insurance and legal permission to use the land for agricultural
purposes.
• Determine what sort of plants are going to be grown. If you are going to
specialise in trees, you may need to have another form of employment
for 1–3 years while the trees become established. If you are going to grow
vegetable plants, decide whether you intend to sell whole vegetable crops,
such as cauliflower, or just the fruits, such as bell peppers or tomatoes.
• Seeds can be harvested from your own plants or from the wild. If you plan to
buy seeds from a supplier, this will be a substantial cost and you will need to
buy the highest-quality seed you can afford.
• Containers also need to be considered. They may be simple ‘peat cups’
for seasonal vegetables or flowers or they may be expensive, large plastic
containers for growing potted shrubs and trees.
• Growing media, soil conditioners and mulches will be a substantial cost for
a new nursery. You will need to try to generate your own compost as soon
as possible. This may not be a possible source of organic material at the
beginning of your venture.
• You will need to buy equipment and make sure that you and your staff know
how to use it properly without risk of injury. Equipment may vary from
irrigation pipes and sprinklers to tractors with loader buckets, depending on
the type of plants to be grown. It is possible that you will need a truck and
trailer for moving plants and materials, and making deliveries to customers. To
be able to develop an accurate business plan, you should consider everything
you will need to get started, even shovels, hoes and rakes.
• Learn about the local growing conditions in the area. Investigate whether
there are problems with pests, diseases or insects. You may need to buy
additional equipment and chemicals to spray the crops.
• Make sure you know where your market is. Whatever you decide to grow,
you need to sell it. If you are choosing to supply hotels, be aware of expected
grading or standards.
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21: Nursery management technologies
Revision map
Nut-grass
Plastic
containers
Stones
Budding
Plants with
hard woody
stems
Sterilisation
is important for
plain soil, soil blends or
completely soil-less
mixes that have
previously
been used
Weed plants
with seeds
Bottles
Materials that
should be removed
from the compost
mix
Leaves
Soft
stems
Methods
Propagation
A nursery
business is one
of the easiest to
set up and begin to
make profit
Nursery
management
technologies
Seeds
management
and storage
Seeds
Tissue culture
is the production of new
genetically identical plant
from a small piece of plant
tissue placed in a suitable
growth medium
Compost is added
to plants to provide
nutrients
Compost
Seed quality:
purity test,
viability test,
germination test,
seed vigour test
Plugs
Grafting
Sprigs
Organic matter
is decomposed to
form compost
manure for
growth
Rejected
fruits and
vegetables
Entrepreneurship
Running a
nursery is hard work
and plants will die if
their needs are
not met
Seed storage:
cool,
dry,
watertight,
airtight
Growing
media
Establishing
plants in
nurseries
Greenhouse
technician
Peat
Organic
Careers
Wood
residues
Plant growth
regulators (PGRs)
are used to make plants
grow quickly and
improve
profits
Hulls
Bagasse
Cuttings
Tools
Garden
trowel
Nursery
worker
Horticulturist
Sand
Inorganic
Urea
formaldehydes
Calcined
clays
Expanded
polystyrene
Dibber
Watering
can
Perlite
Garden
hand rake
Hand fork
Weeding
knife
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Section E: Farm management technologies
Examination-style questions
Multiple-choice questions
Write down the number of the question followed by the letter of the correct answer.
1.
2.
3.
4.
Adding limestone to compost is done to optimise which one of the following?
A Organic material
B pH
C Soil
D Plants
State why soil is heated to sterilise it before propagation.
A To make sure pathogens and fungi have been killed.
B To make the soil easier to sell.
C To make the soil warmer for the plants.
D To make the roots grow faster.
Choose the inorganic growing media from the following items.
A Bagasse
B Peat
C Perlite
D Sawdust
Which of the following is used to plant seeds in a nursery?
A Watering can and spade
B Dibber and hand trowel
C Tractor and plough
D Compost and perlite
Short-answer and essay-type questions
5.
6.
7.
8.
9.
306
Describe how different tests can be performed on seeds to ensure they are viable and
ready to germinate.
Describe how compost is made, and explain why each stage is important.
Using examples, explain why the tools used in a nursery are different from the tools used
in field agriculture.
Explain why growing media for plant propagation is sterilised.
Choose a nursery career and describe the tools and equipment that would be required to
carry out this career.
Section E: Farm management technologies
22
Technologies for
non-conventional
crop production
By the end of this unit you should be able to:
✔ explain the importance of alternative crop production systems in the
Caribbean
✔ recommend crop cultivars that are tolerant or resistant to specific abiotic and
✔
✔
✔
✔
✔
✔
Concept map
biotic stresses
design a suitable cropping system for production of a crop under conditions
of environmental stress using appropriate techniques and technologies
recommend appropriate strategies for water and nutrition management
demonstrate the use of simple water and nutrition management technologies
design an integrated pest management programme
demonstrate the use of pest management technologies
demonstrate the use of appropriate technologies for conservation of
environmental resources.
Technologies for non-conventional crop production
Alternative crop
production systems
Cropping system
designs
Protected agriculture
Soil-less agriculture
Container gardens
Hydroponics
Aggregate
Aggregate-free (NFT)
Organic
Abiotic and biotic stresses
Heat resistant / tolerant
Drought resistant / tolerant
Disease resistant / tolerant
Herbicide resistant / tolerant
Preventing environmental stress
Abiotic
Biotic
Cropping system technology
Water management
Nutrient management
Technology to determine crop
nutrient needs
Integrated pest
management
Cultural
Chemical
Contact pesticides
Systemic pesticides
Residual pesticides
Spray calculations
Biological
Irrigation
Nutrient application technologies
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Section E: Farm management technologies
22.1 The importance of alternative crop
production systems in the Caribbean
A number of different production systems are used in the Caribbean. This is because
the island nations have an equatorial climate, and farmers have to maximise the
land they have, and optimise the labour, tools and chemicals they have available
to create as much food and profit as possible. Farmers in the Caribbean have
developed alternative ways to grow crops to overcome the challenges they face.
Protected agriculture
protected agriculture ▶
Protected agriculture is the cultivation of high-value vegetables and other
horticultural crops in greenhouses. Protected agriculture allows farmers to grow
cash crops on small plots in marginal, water-deficient areas where traditional
cropping is not viable.
Protected agriculture has a number of advantages.
• There is a large increase in yield, produce quality and revenue.
• This system uses water efficiently, so it saves large amounts of water.
• There is a significant reduction in pesticide use. This results in lower
production costs and healthier produce.
• Production takes place all year round. This allows farmers to take advantage
of market seasonality and higher prices.
Low-cost greenhouses are made locally by small-scale entrepreneurs. Integrated
crop management methods have been developed to maximise the benefits of
greenhouse cultivation.
Soil-less agriculture
soil-less agriculture ▶
In soil-less agriculture, crops are grown in nutrient solutions. This is a popular
way to grow plants indoors, which reduces the risk of crops being exposed to pests
and harsh weather conditions.
Advantages of soil-less agriculture
• Soil-less agriculture does not require the use of toxic chemicals. Farmers do
not need to use fertilisers to increase crop yield or spray pesticides to keep
weeds and soil-based pests away.
• Soil-less agriculture is ideal in urban areas where space is too limited for soilbased gardens.
• Nutrient requirements for crops grown in soil-less systems are determined in
advance so nutrient and media losses can be reduced. (The loss of nutrients
occurs when the plant grows and takes up nutrients or uses soil organic
matter.)
• Soil-less cultivation is believed to cause less pollution.
• When compared with soil-based cultivation, the yields from soil-less
cultivation are significantly higher as a result of intensive practices and
continuous, year-round production.
Disadvantages of soil-less agriculture
• Crops cultivated using this approach are more prone to attacks from diseases
as a result of the high moisture levels that are present in soil-less agriculture.
• Crops are also more vulnerable to rapid death as a result of their lower
resilience. (Lower resilience is caused by a lack of exposure to soil
biodiversity.)
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22: Technologies for non-conventional crop production
Container gardens
container gardening ▶
Practical activity:
Design a container garden for your
school. Choose plants that you can
harvest throughout the year so that
there is a continuous supply of fruit
and vegetables.
Container gardening, or pot gardening, is the practice of growing plants,
including edible plants, exclusively in containers instead of planting them in the
ground. A container in gardening is a small, enclosed and usually portable object
used for displaying live flowers or plants. It may take the form of a pot, box, tub,
basket, tin, barrel or hanging basket.
The most commonly used containers for plants are pots, traditionally made of
terracotta but now more often made of plastic, and window boxes. Container
gardens are useful in areas where the soil or climate is unsuitable for the plant or
crop in question. Limited growing space, or growing space that is paved over, can
also make this option appealing to a gardener. In addition, this method is popular
for urban horticulture on balconies of apartments where gardeners cannot use
the outside ground for a traditional garden.
Advantages of container gardens
• There is less risk of soil-borne diseases.
• There are very few weed problems.
• There is more control over moisture, sunlight and temperature than with soilbased gardening.
Hydroponics
hydroponics ▶
Hydroponics is the science of growing plants without the use of soil. Plants
are fed on mineral nutrient salts dissolved in water. Any plant can be grown
using hydroponics, but it is most widely used to grow greenhouse crops such as
peppers, tomatoes and cucumbers. Roses, and other flowers for the cut-flower
market, are often grown hydroponically.
Hydroponic techniques
There are two different hydroponic techniques.
1. Aggregate technique: This technique requires aggregates or other porous
rooting media (substrate), such as perlite, to support the plant roots.
2. Nutrient film technique (NFT): This technique does not require aggregates to
support the plant roots.
aggregate system ▶
The aggregate system is a system where plants are grown in a pot of aggregate
and given water containing a liquid fertiliser so the plants do not dry out. The
spaces between the aggregate particles contain air so that the roots do not
suffocate. Although the plants can be watered using a watering can, they are
usually watered via a drip system fed by a pump from a stock tank of nutrient
solution. This liquid is recirculated via a trough below the plants that runs back
to the stock tank.
There are two hydroponic systems commonly in use in the Caribbean.
• The wick system: This simple system uses capillary action to feed the nutrient
solution to the root zone of the plants, so no pump is required.
• The ebb and flow system (also called the flood and drain system): Plants are
placed in a tray, which is periodically filled with nutrient-rich water pumped
out of a reservoir below the plants. This system uses gravity to return the
water to the reservoir to be re-used.
Figure 22.1 Lettuce NFT / hydroponics.
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Section E: Farm management technologies
growth
medium
grow
tray
grow
tray
overflow
wick
reservoir
wick
nutrient
solution
air
pump
fill /
drain
fitting
excess nutrient solution
returns to the reservoir
reservoir
air stone
solution is pumped
to the grow tray
pump
Figure 22.2 Wick system.
timer
Figure 22.3 Ebb and flow system.
nutrient solution ▶
A nutrient solution is a balanced mixture of major nutrients (nitrogen,
phosphorus, potassium, magnesium and sulphur) and a very low concentration
of minor nutrients. A pH of 5.8–6.2 is crucial for the plants to grow well. Citric acid
is used to lower the pH and baking soda is used to raise it. The nutrient solution
should be checked because when the plants use up water, the solution becomes
more concentrated. This can lead to ‘salty’ roots, which harms the plants.
aggregate-free system ▶
Aggregate-free systems (including the systems that use the nutrient film
technique) do not require a growing medium. Because there is no need for a
growing medium, the costs are lower and less labour is required.
The nutrient film technique allows the nutrient solution to trickle along gently
sloping covered gutters. Plants are grown in small pots at intervals in the gutters.
Their roots form a thick mass in the humid, well-aerated gutters and very strong
plant growth can result. The surplus nutrient solution trickles back to a stock tank
and a pump is used to recirculate it. If the pump stops, the plants soon die because
there is no supporting medium or moisture to help the plants survive until the
nutrient solution circulation can be restored.
Organic agriculture
organic agriculture ▶
Practical activities:
Use your knowledge of what plants
require and recycling materials
available at school to do the
following activities.
1. Design a simple hydroponics
system.
2. Build the system.
3. Plant the system with a fastgrowing salad crop.
310
Organic agriculture is where natural methods are used to control pests and
disease. These methods include well-designed crop rotations, using natural
predators and developing good soil and healthy crops that have a natural resistance
to pests and diseases.
Organic agriculture is different from standard agriculture in the following ways.
• Artificial chemical fertilisers are prohibited. Instead, organic farmers
develop a healthy, fertile soil by growing and rotating a mixture of crops,
adding organic matter such as compost or manure and using legumes to fix
nitrogen from the atmosphere in the soil.
• Pesticides are severely restricted. Instead, organic farmers develop nutrientrich soil to grow strong, healthy crops. Wildlife is used to control pests and
disease by using predators that eat the prey that is affecting the crops. For
example, ladybirds and hover flies feed on aphids, birds eat caterpillars and
fish eat insect larvae.
22: Technologies for non-conventional crop production
• Animal welfare is very important, so a truly free-range life for farm animals is
guaranteed. Rabbits and chickens are not caged in the organic system.
• Different types of crops and animals are raised on the farm and rotated around
the farm over several seasons. Fallow periods are used too. This mixed
farming approach helps break cycles of pests and disease and builds fertility in
the soil.
• The routine use of drugs, antibiotics and wormers is not allowed. Instead, the
farmer uses preventative methods, such as moving animals to fresh pasture
and keeping smaller herds and flocks.
• Organic systems do not allow the use of genetically modified (GM) crops and
ingredients.
ITQ 1
Organic farming is good for the environment in the Caribbean and the farmers,
because the organic farms can become certified – either by the USA or the UK –
which allows the farmers to sell their products at a very good price.
Name FIVE alternative crop
production systems.
22.2 Crop cultivars that are tolerant or resistant
to specific abiotic and biotic stresses
cultivar ▶
The term ‘cultivar’ is a short form of ‘cultivated variety’. These are plants that are
bred for desirable characteristics, for example, increased yield or flavour. Almost
all of the world’s agricultural food crops are cultivars.
Key features of protected agriculture
in crop production, CARDI
Farmers use protected structures for commercial crop production in the Caribbean as the
structures:
• provide year-round production, including the option of an extended growing season for specific
crops
• allow the integration of precision agriculture
• achieve consistently high-quality produce.
The most common protected agricultural structures are single tunnel structures. These structures are around 9 m
wide and 16–30 m long. They have a galvanised metal pipe frame covered with clear plastic or shade cloth.
Protected agriculture offers the farmer benefits.
• It allows the farmer to treat soil and other propagating media with chemical agents to remove pests before
planting.
• It allows the farmer to adjust the pH of nutrient solutions and propagating media.
• It allows the farmer to use drip irrigation, hydroponics or aquaponics.
• It allows the farmer to use soil-based or soil-less media (perlite, peat moss or coconut coir) in raised beds or containers.
• It allows the farmer to monitor soil and environmental conditions using data loggers.
The main Caribbean crops grown using protected agriculture are vegetable crops and the seedlings of vegetable
crops, for example, tomato, sweet pepper, lettuce, cucumber, cantaloupe, honeydew melons, cabbage, broccoli, ochro,
pumpkin, string beans and culinary and medicinal herbs.
The major challenges of growing crops using protected agriculture are high temperatures, high humidity, lack of suitable
varieties, high cost of infrastructure and inputs, and difficulties with pest management.
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Section E: Farm management technologies
Heat-resistant and heat-tolerant cultivars
Heat-resistant cultivars have been developed to withstand hot weather without
wilting in the heat. ‘Long-standing’ spinach cultivars are open-pollinated, which
means that they reproduce through natural pollination and seeds that grow true
to type. They tolerate heat so well that these types of spinach are deliberately
cultivated commercially in regions bordering deserts.
bolt ▶
It is especially important to grow heat-tolerant salad crops. Lettuce prefers the
cool days of spring and autumn, with air temperatures around 15 °C. When the
weather warms up, lettuce will often bolt. More sunlight during longer days and
hot weather causes the plant to set a flower and grow a seed stalk, resulting in the
leaves tasting bitter.
Drought-resistant or drought-tolerant cultivars
Cultivars are being developed that are resistant to drought. These are crops that
have lower water requirements and are better able to cope with water stress.
Drought tolerance allows a plant to maintain its biomass production during arid or
drought conditions. Some plants are naturally adapted to dry conditions, surviving
with protection mechanisms such as desiccation tolerance or detoxification.
Desiccation tolerance is the natural ability of a plant to endure extreme dryness
or drought conditions, resuming normal function when water is readily available.
Detoxification is where a plant can tolerate high concentrations of heavy metals
found in soil (which often occur with drought-like conditions) without being
poisoned. Other plants, specifically crops such as maize, wheat and rice, have
become increasingly tolerant to drought with new varieties created via genetic
engineering (see Unit 6).
Disease-resistant or disease-tolerant cultivars
disease resistance ▶
disease tolerance ▶
Disease resistance is the reduction of pathogen growth on or in the plant (and
hence a reduction of disease). Disease tolerance describes plants that exhibit
little disease damage even when the pathogen levels are high.
Host plant
Plant disease resistance protects plants from pathogens in two ways:
• by pre-formed structures and chemicals
• by infection-induced responses of the immune system.
No disease
No
disease
No disease
Disease
No
disease
Pathogen (disease
carrying organism)
Figure 22.4 The disease triangle.
ITQ 2
Explain why the disease triangle
is used.
312
Plant resistance is usually specific to certain pathogen species or
pathogen strains. Disease outcome is determined by the threeway interaction of the pathogen, the plant and the environmental
conditions – known as the disease triangle.
No
disease
No disease
Favourable
environment
Herbicide-resistant or herbicide-tolerant
cultivars
Herbicide-tolerant crops are designed to tolerate specific herbicides, which kill
the surrounding weeds but leave the cultivated crop intact. Genetic engineering
offers the potential to add herbicide tolerance without losing the other agronomic
and disease resistance traits already incorporated in the cultivar. There are
currently difficulties with herbicide resistant crops, particularly those that have
been developed to tolerate glyphosate. Due to glyphosate’s universal use, weed
populations are evolving glyphosate resistance too, through interaction with
genetically engineered crops.
22: Technologies for non-conventional crop production
Newer herbicides are being developed all the time. As with glyphosate, it is vital
that they are not harmful to farmers or to anyone who uses or eats the processed
crop. Organisations such as the European Food Safety Authority (EFSA) analyse
the safety of such materials. One major manufacturer of such chemicals has
introduced a ‘Transparency Initiative’. This published study summarises the
human and environmental safety of many active substances evaluated by EFSA.
It also gives access to the full safety study reports behind the summaries. Through
such initiatives, local governments and departments of agriculture can give
reliable advice to their growers.
Practical activity:
In groups, research a type of
cultivar that is frequently grown
in the Caribbean. Present your
research to the rest of the class.
22.3 Design a suitable cropping system
cropping system ▶
ITQ 3
What is a cropping system?
Tillage system and residue
management
• No-till
• Mulch tillage
• Strip tillage
• Residue removal (full or partial)
• Residue burning
A cropping system is the species and sequence of crops grown and the
practices used for growing them. Cropping systems traditionally maximised crop
yields. However, there is a strong need to design cropping systems that take the
environment into consideration. Conserving soil and water and maintaining
long-term soil productivity depend largely on the management of cropping
systems. It is the cropping system that influences the amount of soil erosion there
is and the levels of soil organic matter. Diverse and properly managed cropping
systems can maintain or even improve soil productivity and restore moderately
degraded lands by improving soil resilience. Table 22.1 describes the components
of cropping systems.
Cropping system
Nutrient and water management Erosion control practices
• Fallow systems
• Monoculture
• Strip cropping
• Multiple cropping
• Contour strip cropping
• Crop rotations
• Cover crops
• Mixed and relay cropping
• Organic farming
• Precision farming
• Use of amendments
(e.g. manure, compost)
• Enhancement of biological
nitrogen fixation
• Irrigation / drainage practices
• Water harvesting
• Conservation buffers
• Windbreaks and buffer strips
• Terraces and engineering
devices
• Sediment traps
Table 22.1 Components of cropping systems.
ITQ 4
How does spacing prevent
environmental stress on plants?
Preventing environmental stress using spacing and planting arrangements
Plants need enough sunlight and moisture, the right soil conditions and some
thinning to ensure they have space to grow without competition from other
plants. When these requirements are met, the plants grow well without stress.
The spacing between plants is determined by the carrying capacity of the land.
This prevents plants in a crop competing with one another for sunlight, moisture
and soil nutrients. Appropriate spacing also prevents pests and diseases from
spreading so easily through the crop.
Planting arrangements such as strip cropping, mixed and relay cropping and cover
cropping can all reduce plant stress as the plants have different requirements and
remove different nutrients from the soil. Chosen correctly, the variety of plants
should complement one another, reducing the spatial spread of pests and diseases.
Figure 22.5 Intercropping.
Choice of sowing dates plays a very important role in reducing plant stress.
Sowing dates are selected to get the best environmental conditions, such as
humidity, temperature, rain and sunshine hours, to ensure the seeds germinate
and the seedlings grow well. Sometimes pest population and disease infestation
can be changed by altering sowing dates, and in this way avoiding a pathogen’s
preferred environmental conditions. For example, sorghum should be sowed
early to reduce the infestation of sorghum shoot fly.
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Section E: Farm management technologies
Herbicide-resistant / tolerant cultivar bred,
Puerto Rico
Herbicide-tolerant crops are designed to tolerate specific broad-spectrum herbicides, which kill the surrounding weeds,
but leave the cultivated crop intact. The broad-spectrum herbicide that the breeds are engineered for is glyphosate, and
the varieties are often marketed as ‘Roundup ready’. However, they do not result in higher yields than non-genetically
engineered crop varieties, which disappoints some farmers. Roundup-ready crops of corn, cotton and soybeans have been
grown in Puerto Rico by agricultural technology company, Monsanto*, since 1998. GMO cotton seed bred in Puerto Rico is
used to develop seeds that are sold throughout the world. GMO soybeans bred on the island are developed into seeds that
are used by farmers throughout North and South America.
There has been considerable unrest on the island around the health risks associated with glyphosate. Monsanto, while a
major employer in Puerto Rico, scaled back its research and development operations as part of restructuring in 2016.
In 2018, the World Health Organization’s International Agency for Research on Cancer (IARC) said the chemical is
‘probably’ carcinogenic (cancer causing) to humans. But the US Environmental Protection Agency (EPA) – the
agency that determines which risk labels should be on chemical containers – and Monsanto both carried out
extensive research to see whether there was a connection between glyphosate and users of the chemical
getting cancer. The results were inconclusive, so glyphosate does not currently have a carcinogenic
warning on the product label. (Product labels are found on every Roundup chemical container.)
*Monsanto was taken over by Bayer in June 2018.
Abiotic environmental stress
abiotic stress ▶
Abiotic stress is the negative impact of non-living factors on crops in an
environment. Abiotic stress factors, or stressors, are naturally occurring factors
such as intense sunlight, temperature or wind that may cause harm to the plants
and animals in the area affected. Abiotic stress cannot be avoided. Abiotic stress
is the most harmful factor concerning the growth and productivity of crops
worldwide. Research has also shown that abiotic stressors are at their most
harmful when they occur together, in combinations of abiotic stress factors.
Reducing the impact of abiotic stress on crops
A plant’s first line of defence against abiotic stress is in its roots. If the soil holding
the plant is healthy and biologically diverse, the plant will have a higher chance
of surviving stressful conditions. The plant responses to stress are dependent on
the tissue or organ affected by the stress.
facilitation ▶
ITQ 5
Describe the difference between
abiotic stress and biotic stress.
Facilitation is the positive interaction between different species of plants (how
plants work together). In areas of high stress, the level of facilitation is greater
because the plants need a stronger network to survive in a harsher environment,
so their interactions between species, such as cross-pollination, become more
common to cope with the difficulties in their environment.
Biotic environmental stress
biotic stress ▶
314
Biotic stress occurs as a result of damage done to an organism by other living
organisms, such as bacteria, viruses, fungi, parasites, beneficial and harmful
insects, weeds and cultivated or native plants.
22: Technologies for non-conventional crop production
Salt stress in plants
Soil salinisation threatens approximately 831 million hectares of land. This is about 20% of the world’s irrigated agricultural
land and 2% of the world’s non-irrigated agricultural land. Soil salinisation is where water-soluble salts accumulate to high
levels in the soil. This is harmful to plants because water-soluble salts can prevent many cellular functions. For example, if
water uptake is limited in some way, photosynthesis is reduced.
One of the primary responses to abiotic stress, such as a high salinity, is the disruption of the sodium / potassium
(Na+ / K+) ratio in the cytoplasm of the plant cell. High concentrations of sodium, for example, can decrease
the plant’s ability to take up water and also alter enzyme and transporter functions. Some plants have
adapted so that they can restore the correct levels of these chemicals; this has led to a wide
variety of stress-tolerant plants.
Practical activities:
Go for a walk on a farm near your
school. Look at the plants and see
whether you can identify the stress
factors that are affecting them.
1. Make a table of abiotic and
biotic stress factors.
2. Write down solutions to reduce
the impact of each stressor.
Biotic stressors cause large economic losses to cash crops. Plants are exposed to
many stress factors that reduce the yield of the cultivated plants or affect the
quality of the harvested products. Although there are many kinds of biotic stress,
the majority of plant diseases are caused by fungi.
Reducing the impact of biotic stress on crops
Plants have co-evolved with their parasites for several hundred million years.
This has resulted in a wide range of plant defences that protect the plant against
microbial pathogens and herbivorous pests, minimising the frequency and impact
of attack. For example, using high metal ion concentrations from the soil allows
plants to reduce the harmful effects of biotic stressors, without suffering from the
harmful effects of exposure to high concentrations of metal ions.
Cropping system technology
remote sensing ▶
ITQ 6
Explain how technology can be used
to make agricultural management
decisions.
Methods of remote sensing are used to detect the environmental stresses
that limit plant growth and yield. Remote sensing monitors the plant without
damaging it in any way. There is technology that can compare the remotely
sensed data with expected crop data. Rapid advances in computing and positionlocating technologies (which include remote sensing from ground-, air- and
space-based platforms) can now provide detailed space and time information on
how plants are responding to their local environment. This information can be
used for agricultural decision-making, such as deciding whether a crop needs to
be sprayed with a herbicide.
22.4 Strategies for water and nutrition
management
Water management strategies
Figure 22.6 Rainwater harvesting slope
with tank and overflow to a well.
Water requirements depend on the crop being grown and the location chosen.
Farmers can manage the water on their farms in different ways. They may use
natural rainfall or irrigation. They may decide to harvest and store rainwater that
falls on the farm buildings. How the farmers manage the water on their farms
depends on the environmental opportunities (for example, proximity to a river),
or money available for the purchase of irrigation equipment or rainwater storage
tanks. Farmers need to choose crops that suit the amount of water that they have
available. With global warming and the unpredictability of rainfall, this can be
challenging.
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Section E: Farm management technologies
Nutrient management strategies
Nutrients can be provided to plants naturally from the soil, or increased through
amendments such as manure or compost. Chemical additions such as specific
fertilisers have to be measured carefully before being applied, either via an irrigation
system or sprayer, to ensure the correct quantity is being given to the crop. Money is
an important factor in nutrient management strategies. Free nutrient management
strategies mean the yield is entirely dependent on nutrients existing in the soil.
Artificial fertilisers are an alternative option, but they can be expensive and affect
the environment. These will not benefit the crop unless the nutrient requirement
has been balanced appropriately using the correct fertiliser ratio.
Use of technologies to determine crop nutrient needs
The ability to collect digital data is rapidly changing agriculture. The ability to
collect very large amounts of data, integrate data sources, access the data from
practically anywhere and analyse large sets of data all help farmers with their
decisions.
Here are some of the ways new technology allows data to be collected and
analysed.
• Satellite and drone imagery: Using remote-sensing technologies, such as
satellite images, provides data that can be used to calculate the necessary
quantity of nitrogen accurately (see variable rate nitrogen in Unit 20).
• Different sensors: These are being developed to inform farmers about the
quantities of other nutrients to be added. The most common ones are the
normalised difference vegetation index (NDVI), which estimates vegetation
cover, the canopy chlorophyll content index (CCCI), which measures seasonal
changes in canopy density and the canopy nitrogen index (CNI), used to
estimate the amount of biomass in the crop canopy.
• Field sensors: Nitrogen sensors can be installed in a field or on machinery such
as tractors, to collect data. There are a large number of field sensors, including
those that measure nitrogen levels, soil moisture levels and soil pH.
• Weather data: Weather data from thousands of weather stations is being
collected and analysed. Accurate weather forecasts are important for many
decisions that farmers make, including the timing of sowing seeds and
chemical applications.
• Data libraries: Several international organisations publish data libraries on
soils and their properties, with some digital agriculture companies creating
privately owned data libraries of crop nutrient requirements, yields and soils.
These are based on their own data that has been analysed using computer
models.
• Farmer inputs: Farmers’ own records stored using cloud-based applications
(apps). The large amount of data creates new opportunities for knowledgesharing and learning from other people. This is particularly useful for local
farming communities.
See Unit 20 for nutrient management calculations and rates.
316
22: Technologies for non-conventional crop production
Water management, Jamaica
Irrigation has always played a significant role in Jamaica’s agriculture, and the need to
continually improve irrigation practices has long been recognised. Over the years, some
of the improvements that have been made include channel lining and using closed pipes
to improve the efficiency of water-transport infrastructure, the use of water measuring
techniques to encourage improved management and the use of overnight storage
facilities. Approximately 9% (about 25 000 ha) of the total area under cultivation is
irrigated, and about 9 000 ha require rehabilitation, with water needed to stabilise the
soil for crop growth.
Half of the total irrigated area comprises public schemes that are managed by the
National Irrigation Commission (NIC), while the other half is on individual private
systems and on commercial estates, where banana, papaya and sugar cane are the
major crops grown. Of the area, 75% is under surface irrigation: 17% of this is equipped
with sprinklers and 7% with micro-irrigation or localised systems. Groundwater is being
threatened by saline intrusion and contamination from industrial effluents and
untreated sewage discharges from towns, which is why wastewater re-use is
included in the National Irrigation Development Plan (NIDP).
Figure 22.7 Rainwater harvesting
system, Jamaica.
22.5 Simple water and nutrition management
technologies
irrigation ▶
rain-fed or dry land farming ▶
drainage ▶
Irrigation is the application of controlled amounts of water to plants at needed
intervals. Agriculture that relies on direct rainfall only is called rain-fed or dry
land farming. Irrigation helps people to grow crops, maintain landscapes, and revegetate disturbed soils in dry areas and during periods of low rainfall. Irrigation
also has other uses in crop production, including frost protection, suppressing
weed growth in grain fields and preventing soil consolidation. Irrigation systems
are also used for cooling livestock, suppressing dust, disposing of sewage and in
mining. In farm management plans, irrigation is often grouped with drainage.
Drainage is the removal of surface and sub-surface water from a given area.
Irrigation technologies
• Surface irrigation, often called flood irrigation, is where land is flooded
regularly. Farmers use shallow ditches to catch the water to keep it on the
land to irrigate the crops. If river levels are low and flooding is unlikely to
occur, water can be pumped or lifted from the river, by people or animals, to
the level of the fields.
• Drip (or micro) irrigation, also called trickle irrigation, is where water is
delivered at or near the root zone of plants, drop by drop. This method can be
the most water-efficient method of irrigation and, if it is managed properly, it
can minimise evaporation and runoff.
Figure 22.8 Drip irrigation from a line,
bell pepper.
317
Section E: Farm management technologies
Figure 22.9 Sprinkler in corn.
• Sprinkler irrigation, sometimes called overhead irrigation, has water piped
to one or more central locations within the field and then distributed by
overhead high-pressure sprinklers. A system using sprinklers, sprays or
guns mounted overhead on permanently installed risers is called a solid-set
irrigation system. Sprinklers that can rotate are called rotary irrigation systems
and the rotations can be a full or partial circle. Travelling sprinkler systems
are those where the sprinklers are mounted on automated moving platforms
connected to the water source by a hose. Sprinkler systems can irrigate land
unattended.
• Sub-irrigation, or seepage irrigation, is used where field crops are grown in
areas with high water tables. It is a method of artificially raising the water
table to allow the soil to be moistened from below the plants’ root zone.
Often those systems are located on permanent grasslands in lowlands or
river valleys and combined with drainage infrastructure. Sub-irrigation is
also used in commercial greenhouse production, usually for potted plants.
Water is delivered from below, absorbed upwards, and the excess collected
for recycling.
22.6 Integrated pest management
integrated pest management (IPM) ▶
ITQ 7
State FOUR irrigation technologies.
ITQ 8
What is integrated pest
management?
Integrated pest management (IPM) aims to control pests by using a
combination of methods to keep pest populations at low levels rather than totally
eliminating them. IPM uses cultural and biological control methods instead of
relying solely on chemicals.
If pesticides are used, they should be chosen for their short-term toxicity; this
means they break down to harmless substances in a short time. Also they should
not be used over a long period as the insect pests could develop resistance to them.
Development of pesticides is expensive, so relying just on pesticides will cost the
farmer more money than integrating cultural and biological control methods.
22.7 Pest management technologies
Cultural techniques
Here is a list of some cultural techniques.
• Removal of pests by hand: This technique is time-consuming but effective for
caterpillars on cabbages. It avoids the use of chemicals that could contaminate
the produce but it is difficult to carry out for most pests.
• Disinfection and sterilisation of soil: This technique kills weed seeds, insect
eggs and larvae and fungal spores. Banana corms can be disinfected with hot
water.
• Destruction of any infected plants or produce: Citrus trees infected with a
virus are burned.
• Crop rotation: This technique reduces the spread of insect pests that infect
specific crops.
• Planting disease-resistant varieties of crop plants: This technique prevents or
reduces infection. Disease-resistance can be selected for and many varieties of
crop plants are available (see Unit 6).
Chemical control
contact pesticides ▶
318
Pesticides are classified by the way they work. Contact pesticides are sprayed
onto the crop and coat the plants. These pesticides do not stay on the crop plants
for long. If they get washed off by rain, they will have to be re-applied to control
22: Technologies for non-conventional crop production
systemic pesticides ▶
residual pesticides ▶
the pest. Systemic pesticides are absorbed through the leaves and roots of crop
plants and are carried around the plant by translocation. The pesticide remains in
the plant for a long time and can protect the crop from infestations before they
occur. Residual pesticides are sprayed on the land before a crop is planted.
These pesticides kill weed seedlings, fungal spores, insect eggs and larvae. They
have a relatively long-lasting effect, although heavy rainfall will cause leaching
from the soil into watercourses. More information can be found in Unit 8.
Practical activities:
1. Design an integrated pest management programme for either the school farm or a family farm. Start by identifying which crops
are likely to respond to cultural techniques, and which of these can be time-managed by the farmer.
2. Next consider the possible pests (weeds or insects). Look at the costs of applying herbicides and / or insecticides to each crop.
3. Once you have decided which cultural techniques you will use and which herbicides or insecticides you will buy, consider the soil
type and the crops that preceded the current planting. From this information, you can decide which crops are most at risk from
pest attack. For example, it may be better to treat one field solely using cultural methods, but spray a higher-risk field three times.
4. Write up your integrated pest management programme using all the information you have gathered. Remember to include time
for labour needed for cultural methods and spraying, as well as the costs of tools and chemicals.
ITQ 9
Why does the area to be sprayed
with a pesticide need to be
calculated?
Calculating the area to be sprayed with a pesticide or herbicide
Length
×
Practical activity:
Complete the spray calculation
for a piece of land 20 m × 15 m
for a pesticide or herbicide of your
choice. Use the information on the
container label to obtain the water
volume and quantity of chemical
(both of these numbers will be in
litres per hectare).
Width
(metres)
Total area
=
(metres)
(square metres)
Water volume
Water for
small area
Total area
÷
10 000
=
×
=
(litres / square metre)
Quantity of
chemical
(litres)
Chemical for
small area
Total area
÷
10
(litres per hectare)
=
(ml / square metre)
×
=
(millilitres)
Figure 22.10 Sprayer calculation.
The correct amount required for the area should always be calculated before the
land is sprayed, as this prevents too much spray being applied. Chemicals have an
optimal quantity to be put on the crop. If too much is sprayed, it will not improve
the crop any further, so the spray is wasted and costs the farmer unnecessary
money. The advisory quantity is on the information label on every pesticide
container. There are also environmental reasons for not over-spraying an area
with more than is required. Usually the advisory quantity is related to the
saturation of the plant or soil. If more spray is applied over this quantity, the
chemical will exist in the environment and be hazardous to wildlife until it is
washed by rainfall into ditches and rivers where it may affect drinking water or
harm aquatic life.
Figure 22.11 Sprayer tank.
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Section E: Farm management technologies
Biological control
biological control ▶
ITQ 10
Explain the principle involved in the
biological control of pests.
Biological control relies on the natural predators or parasites of the pest
organism. The term is usually reserved for the deliberate introduction of one
species (a predator) to control another species (the prey or pest). Biological control
is used mainly against insect pests. The aim is to control the pest but not eliminate
it totally as this deprives the predator of food. Biological control often means that
less of the chemical will need to be sprayed on a crop. Further information about
biological control can be found in Unit 8.
Practical activity:
Follow the instructions to make a bucket of compost tea. Spray it onto half a crop you
are growing at school. Observe and record how it affected the growth.
Making compost tea
Compost tea is made by steeping compost in water. When compost tea is sprayed on leaves, it helps suppress foliar
diseases, increases the amount of nutrients available to the plant and speeds up the breakdown of toxins. Using
compost tea has even been shown to increase the nutritional quality and improve the flavour of vegetables.
To make compost tea, you need actively managed, mature compost. This is compost that has been turned a few times
and allowed to heat adequately so that weed seeds and pathogens have been killed. Worm compost also makes
excellent tea, without the need for turning or checking the temperature. Tea brewed from worm compost that has
been made from paper and woody materials is also high in humic acid, an organic substance that is especially good
for potted citrus or other trees and shrubs, and perennial plants.
To brew compost tea, you will need a 20-litre plastic bucket and these aquarium supplies: a pump large enough to
run three air stones (bubblers), approximately 1 m of air tubing, a gang valve (which distributes the air coming from
the pump to the tubes going to the air stones) and three air stones. You will also need a stick to stir the mixture, some
unsulphured molasses (preferably organic) and some fabric for straining the tea. You will also need an extra bucket
to hold the tea. If the tea is not aerated constantly, the organisms in it will quickly use up the oxygen, and the tea will
start to stink and become anaerobic. An anaerobic tea can harm your plants.
Compost tea made using this bucket method needs to brew for two or three days and then be used immediately.
1. Fill the empty bucket half full of compost. Do not pack it in because the air stones need loose compost to aerate
the mixture properly.
2. Cut a length of tubing and attach one end to the pump and the other end to the gang valve. Cut three more
lengths of tubing, each one long enough to reach comfortably from the rim to the bottom of the bucket. Connect
each one to a port on the gang valve and push an air stone into the other end.
3. Hang the gang valve on the lip of the bucket and bury the air stones at the bottom, under the compost. Fill the
bucket to within 7.5 cm of the rim with water, and start the pump.
4. Once the pump is working, add 30 grams of molasses and stir vigorously with the stick. The molasses feeds the
bacteria and encourages the beneficial species to grow well. After stirring, you will need to rearrange the air
stones so that they are on the bottom and well spaced. Try to stir the tea at least a few times a day, making sure
you rearrange the air stones at the bottom afterwards.
5. After three days, turn off the pump and remove the equipment. Let the brew sit until the compost has settled and
then strain it into the other bucket or directly into your sprayer. You will have about 10 litres of tea. Use the tea
immediately, within the hour if possible.
You can put the solids back on the compost pile or add them to the soil, as there will still be bacterial and fungal
foods left in them.
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22: Technologies for non-conventional crop production
Revision map
Hydroponics is
the science of growing
plants without soil, fed on
mineral nutrient salts dissolved
in water; plants can be in
aggregates or suspended
in solution
Container
gardening is the growing
of plants exclusively in
containers instead of
planting them in
the ground
Organic agriculture
uses natural methods
used to control pests
and disease
Protected
agriculture is the
cultivation of high-value
vegetables and other
horticultural crops in
greenhouses
Soil-less
agriculture is when
crops grown in
nutrient
solutions
Remote
sensing detects
changes in plants caused
by environmental
stresses
Different
cropping systems
used to prevent plants
being stressed by
biotic and abiotic
factors
Drought
Heat
Disease
Varieties of
stress resistant
cultivators are bred
to be resistant
or tolerant
Alternative
crop production
systems
Herbicides
Technologies
for non-conventional
crop production
A system of
pest control that uses
cultural and biological
methods and
chemicals
Technology
used in plant stress
management
Integrated
pest
management
Rain-fed
agriculture uses
natural rainfall
Sprinklers
Spraying compost
tea is more effective than
spreading compost; when
sprayed on leaves, it also helps
suppress foliar diseases and
speeds breakdown of
toxins
Water and
nutrition
management
Irrigation
is the application
of water at regular
intervals
Nutrients
occur naturally within
the soil or are added
to soil
Manure
Compost
Seepage
irrigation
Fertiliser
Drip
Surface
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Section E: Farm management technologies
Examination-style questions
Multiple-choice questions
Write down the number of the question followed by the letter of the correct answer.
1.
2.
3.
4.
Which of the following is a system of cropping?
A Strip tillage
B Monoculture
C Irrigation
D Planting windbreaks
Which of these will help a farmer to manage nutrient levels in a crop?
A No-till
B Sediment traps
C Amendments
D Terracing
Which of the following is a technology that can be used to determine the nitrogen levels
within a crop?
A Remote-sensing
B Weather data
C Normalised Difference Vegetation Index (NDVI)
D Soil moisture sensors
Which of these is a cultural technique for controlling an insect pest?
A Spraying a contact pesticide
B Spraying a residual herbicide
C Introducing an insect predator
D Rotating the crops grown on a piece of land
Short-answer and essay-type questions
5.
(a) Describe how soil-less agriculture is used in the Caribbean.
(b) Explain how soil-less agriculture may increase yield.
6. (a)Describe TWO abiotic stress factors on plants and give local examples of where you
have seen these occur.
(b) Describe TWO biotic stress factors and give local examples of where you have seen
these occur.
7. (a) Describe how environmental stress affects plants.
(b) Explain how cultural methods can reduce environmental stress.
8. (a)Describe the technologies that are currently available to help farmers with decisionmaking.
(b) Suggest ways that technology could be developed to help farmers overcome
challenges in agriculture.
9. Describe the process of making compost tea.
10. Explain why integrated pest management is preferred to chemical control only.
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Section E: Farm management technologies
23
Management
practices for
livestock
By the end of this unit you should be able to:
demonstrate the practices involved in the care of young farm animals
suggest the different housing requirements for different classes of livestock
describe management practices in the rearing of livestock
understand good agricultural practices to avoid the major pests and
diseases that affect livestock
✔ implement control measures for various pests and diseases
✔ discuss the role of biotechnology in animal production.
✔
✔
✔
✔
Concept map
Management practices for livestock
Caring for young
farm animals
Housing
requirements
Brooding
in poultry
Materials
Natural
Artificial
Brooding
in rabbits
Economic
uses
Properties
Deep litter
systems
Battery
systems
Good agricultural
practices
Control measures
Common sheep
infections
Foot rot
Scours
Disease management
in pigs
Health conditions
in cattle
Isolation
Quarantine
Biosecurity
Prophylactic use
of antibiotics
Deworming
Spraying livestock
Vaccinations
Biotechnology in
animal production
Concept
Methods
Benefits
Concerns
Antibiotic and
hormone use
Antibiotic growth promoter
Hormone use
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Section E: Farm management technologies
23.1 Caring for young farm animals
In nature, female animals usually take care of their young until they are old
enough to look after themselves. In livestock farming, farmers take care of the
young animals using recommended farming practices. This is done to increase
production and generate greater profits.
Some management practices are the same for all farm animals, for example,
housing, feeding, cleaning and preventing disease. Other practices are specific to
the young of particular animals.
Brooding in poultry
Refer to Section 12.8 in Unit 12 to revise how to manage chicks.
Figure 23.1 Using a debeaker.
Brooding in rabbits
Refer to Section 12.8 in Unit 12 to revise how to manage young rabbits.
Economic uses of young animals
ITQ 1
Calculate the amount of space that
should be allowed for 30 chicks in an
artificial brooder.
ITQ 2
State the food required for a sixweek-old rabbit.
Most young animals are cheaper to buy than adult animals. Young animals are
needed to maintain the stocks of most farms. If a farm is too small to operate a
breeding programme, the farmer must buy in young animals.
• The production of lambs and kids for meat generates an income annually for
farmers who keep sheep and goats.
• Cows are required to give birth to calves to lactate (produce milk) for dairy
products. The calves are then removed from their mothers at a day old as
humans will use the milk.
• The calves are either kept or sold for beef-fattening. This can take up to three
years before the animal is slaughtered for beef.
• Kids are fattened for a period before being sold for meat, as are chicks that will
be broilers.
• Some chicks are selected to be layers and are kept or sold as layer stock birds.
• A farmer who has a good-quality fish hatchery will do well from the sale of
fish fry to other farmers.
23.2 Housing requirements for farm animals
Several factors, including cost of labour and building materials, are involved in
the design and construction of housing for farm animals.
North East
trade winds
N
E
pen
Figure 23.2 Orientation of a livestock pen.
324
The following major factors also need to be considered.
• Purpose: Consider the type of farm animal, for example, rabbits or poultry.
• Location (site chosen): Consider the stability of the ground and whether it
is well drained and not prone to flooding or landslides. Also consider the
distance to pastures, field plots, manure heaps and other farm buildings.
• Orientation to give protection from the elements: Pens need to be constructed
lengthwise in a northeasterly direction to protect animals from direct sunlight
during the morning and afternoon.
• Ventilation: Good ventilation is needed to disperse heat, foul gases (odours)
and moisture. It promotes air circulation and temperature control.
• Lighting: Natural light is needed during the day and electric lighting is
necessary at night. Good lighting helps to keep away predators and vampire
bats.
23: Management practices for livestock
ITQ 3
List FOUR safety features that should
be included in animal housing.
ITQ 4
Explain why farm buildings should
have rough, sloping concrete floors.
• Predator control and security measures: Consider the use of chain-link fences
with padlocked gates around pens and wire mesh in the upper parts of the
walls to the ceiling. Also consider using floodlights at strategic points around
the buildings from dusk to dawn and ceiling lamps within the pen. Security
measures to keep away stray cats, dogs, vampire bats, mongooses, rats and
thieves may be needed.
• Sanitation: Housing needs to be designed for easy cleaning. The housing
should have a rough, concreted and sloping floor, a channel for the speedy
movement of effluent into a slurry pit or biogas digester, and an appropriate
pathway for moving solid wastes to the manure heap using a wheelbarrow.
• Safety: There should be footbaths at entry points to the pen, grills or covers
over deep drains, channels and pits, several wide exits for speedy removal of
farm animals in case of fire or other emergency and firefighting equipment
located in a convenient place.
Materials
Materials used for farm buildings and animal housing may be grouped into those
available locally and those that are imported. Local materials include lumber
(from local trees such as mora, teak, mahogany, cedar, Caribbean pine), aggregates
(gravel, sharp sand, cement), metals (iron and steel beams, aluminium / zinc
roofing sheets), PVC used for pipes and guttering, and clay and concrete for bricks
and tiles.
Materials are imported from Brazil, Canada and the USA, and include lumber
(pitch pine, plywood, chipboard), metals (galvanised roofing sheets and pipes)
and ceramics (tiles, washbasins, sinks).
Properties of materials
Table 23.1 summarises some materials used in the construction of animal housing.
Structure
Foundations
Floors
Walls
Roofs
Recommended construction material
• Bricks as foundation blocks
• Steel rods
• Concrete: mixture of gravel, sand, cement and water
• Slatted floors: lumber (greenheart, laurier)
• Steel rods, wire mesh and polythene sheets
• Concrete: gravel, sharp sand, plastering sand, cement, water
• Clay or concrete blocks, cement, plastering sand
• Lumber, iron / steel rods, wire mesh
• Lumber (rafters, laths): mora, greenheart or Caribbean pine
• Iron / steel, purlins, galvanised or aluzinc roofing sheets
Table 23.1 Recommended construction materials for animal housing.
Lumber should be hard, strong and durable (long-lasting). Some timbers, such as
greenheart, mora and wallaba, are more durable than others are. Teak, greenheart
and cedar are more resistant to termite attack, whereas Caribbean pine, plywood
and white pine are less resistant. Some timbers, such as Caribbean pine and white
pine, rot readily when partially buried in the soil, so these timbers should be
avoided for use as posts. The durability can be improved by treatment with paint,
creosote, solignum, pressure or heat.
Iron and steel are hard, strong, resistant and heavy. They do not break under
tension, so they are used as the framework for concrete posts and beams, decking
or raised floors and roofs. These metals do rust when exposed to the atmosphere
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Section E: Farm management technologies
and rain, so they are treated with zinc oxide (galvanised) to prevent corrosion.
The coating prevents rusting for some time; after that time has passed, protection
is given by regular painting.
Aluminium and zinc are also hard and strong metals, but they are lighter and
do not rust so they are more durable. They are moulded into roofing beams and
sheets, frames for doors and windows, and louvre blades for windows.
ITQ 5
Name THREE construction materials
that are imported into the
Caribbean region.
The plastic materials used in buildings are tough, rust-resistant and durable, but
they can be broken. These materials can be moulded readily and are most useful
for pipes and fittings for electrical and plumbing systems. If breakages occur, it is
much easier to mend them than it is to mend an iron pipe.
Concrete is used for foundations, floors, drains and pathways. It is tough, hard
and waterproof. It is usually moulded into a non-skid, rough finish that is sloped
for ease of cleaning and washing.
23.3 Housing for broilers, layers and rabbits
eaves extended to
keep out the rain
wire mesh
metal
roof
block wall
Figure 23.3 A poultry pen.
Poultry pens should have the following features.
• Situated in a well-drained area
• Constructed so that they are about 10 m wide and a convenient length
• Oriented lengthwise in an east-west direction to keep out sunshine
• Made of lumber, with an aluminium / zinc roof with eaves extended 1 m to
keep out rain
• A slightly graded concrete floor for easy cleaning and washing
• A brick wall, 30 – 45 cm high, to retain litter in a deep litter system
• Enclosed with wire mesh from the top of the brick wall to the ceiling
• Barricaded with feed bags, especially on the windward side to keep out rain
and cold draughts
• A doorway, 1 m wide, to allow the passage of a wheelbarrow for transporting
feed and waste
• Sufficient ventilation and suitable lighting
Deep litter systems
deep litter system ▶
This type of system is commonly used for the rearing of broilers and layers.
In a deep litter system, poultry are provided with litter material to a depth of
10 –15 cm on the floor of the pen. Local materials, such as bagasse, lawn grass
trimmings, chopped rice straw, dry grass and wood shavings, are used as litter.
The litter is stirred once or twice a week and kept dry at all times.
When calculating the number of birds, it is usual to allow 4–5 birds per m2 for
broilers and 3 birds per m2 for layers. In addition, perches are provided for roosting
and the layers have nest boxes for egg-laying.
Figure 23.4 Deep litter system perches (left) and nest boxes for layers (right).
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23: Management practices for livestock
Battery systems
battery system ▶
In a battery system, birds are housed in cages. This system is mainly used for
layers where land is limited.
The cages have the following features.
• Made with sturdy wire
• A trough for food and water on the outside of the cage
• An outwardly sloping floor to make egg collection easier
• A removable tray beneath the wire floor for the collection of droppings
A cage for a single hen should measure 36 cm long, 30 cm wide and 36 cm high.
Cages designed to hold three hens should measure 90 cm long, 36 cm wide and
36 cm high. The cages may be stacked in three or more tiers.
Figure 23.5 The battery system: layers in
communal cages.
rabbitry ▶
ITQ 6
Calculate the quantity of floor space
that a farmer would need to keep
50 boilers in a deep litter system.
Rabbits
The place where rabbits are reared is called a rabbitry. It consists of cages, called
hutches, which are built to accommodate a single rabbit in an individual hutch or
many rabbits in a communal hutch. Hutches vary in size but an individual hutch
measures 75 cm long, 60 cm wide and 40 cm high. Communal hutches can be
120 cm long but have the same width and height dimensions as an individual
hutch. The floor is usually 1 m above the ground.
Hutches may be constructed of:
• wire mesh only (if they are to be used inside another building)
• wire mesh, wood and roofing material if they are to be sited outdoors under a
tree.
The wire mesh should have 1.5 cm2 holes. Since rabbits are gnawing animals,
wire mesh is placed on the inside of the wooden frame. Nest boxes are placed in
the hutches of pregnant doe rabbits.
Hutches are specially designed so that they:
• are durable and easy to clean
• are well ventilated
• protect the rabbits from rain, sun and cold draughts
• allow droppings to fall through the wire mesh floor onto the ground if the
hutch is outdoors, onto deep litter beneath the hutch if the hutch is indoors or
on to a tray for droppings beneath the wire mesh floor.
rainproof roof
wall facing
the wind
cages
pole
supports to keep
vermin away
Figure 23.6 Rabbit hutches in a shelter.
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Section E: Farm management technologies
23.4 Good agricultural practices to avoid pests
and disease in livestock
Major pests and diseases affecting different classes of livestock
Pests and diseases that affect poultry, rabbits and livestock can be found in Unit 12
Animal nutrition and management.
Good agricultural practices
ITQ 7
Explain what good management
practices can reduce the spread of
infection on a farm.
foot rot ▶
nutritional scours ▶
white scours ▶
To prevent pests and diseases in sheep, the following management practices
should be used.
• Animals are housed in clean, sanitised pens and stalls.
• Feeders, waterers and stalls are cleaned daily.
• Dung and soiled bedding material are removed.
• Nutritious feed and clean drinking water are provided at all times.
• Animals are dewormed regularly.
• Wheel baths and footbaths are used on farms.
• Animals’ hooves are trimmed regularly.
• Animals are sprayed or dusted to remove external parasites.
• Pastures are sprayed to control parasites, such as intestinal worms, ticks and
mites.
• Animals are inoculated against tetanus.
• Sheep are protected from dogs.
• Sick animals are isolated and treated.
Common sheep infections
Foot rot is a disease caused by both fungi and bacteria. It causes lameness because
the soft tissues become swollen and inflamed. Infected tissue should be removed,
the hoof washed in antiseptic solution (such as Dettol) and a solution of copper
sulphate applied. The animal should then be kept on a dry floor until the hoof is
completely healed. Foot rot can be avoided by providing well-drained pastures
and exercise areas.
Nutritional scours can be caused by overfeeding and unsanitary conditions.
The animals produce watery faeces with no offensive smell. This can be treated
by giving the animals cod liver oil, mineral oil or baking soda. White scours is
caused by bacteria and animals become listless, lie down and produce yellowishwhite, smelly faeces. Affected animals should be isolated, pens and all equipment
should be sterilised, and the hooves should be washed in antiseptic solution.
Disease management in pigs
Major problems, such as scouring and parasites, can be avoided by good
management practices. Pens, feeding troughs and equipment should be cleaned
and sanitised regularly. The removal of faeces and soiled bedding should be
carried out daily. Many pigs reared in intensive systems are given antibiotics and
medication in their feed to prevent infections, but this is not permitted if animals
are organically reared.
Scouring is more common in piglets and may be caused by bacteria such as E. coli.
Infected animals should be isolated and treated with antibiotics.
Animals kept outdoors are more prone to worms and parasites. Dips, sprays and
dusting powders can control external parasites. Rotational grazing can be used
for animals kept outdoors. Resting pasture should be sprayed to control parasites
such as ticks.
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23: Management practices for livestock
Pigs can be affected by respiratory diseases such as pneumonia and swine
influenza. Affected animals are separated from the herd, kept warm and dry and
given antibiotics.
Figure 23.7 Dairy cow with mastitis
treated with iodine.
Health conditions in cattle
The following pests and diseases affect cattle.
• External parasites: Lice, ticks and mites cause irritation, suck blood and may
cause mange. They can be treated or prevented using sprays or dips. Good
housing and hygienic conditions can prevent infestations.
• Bacterial infections: Mastitis causes sore, inflamed udders and affects the milk.
It is treated with antibiotics.
• Foot and mouth disease: This is caused by a virus and affected animals have to
be slaughtered. The disease can be prevented by vaccination.
• Coccidiosis: This disease is caused by a protozoan and it can spread from
adults to calves. The disease causes diarrhoea in young cattle. It is treated with
sulphur drugs and good hygiene.
Antibiotic and hormone use
Agricultural practices such as the use of antibiotics and hormones will help to
prevent animals becoming infected and diseases spreading. Often antibiotics are
put into animal feed or drinking troughs to protect the animal from the many
diseases that thrive in intensive farming systems. Prophylactic (sometimes called
preventative) or ‘routine’ antibiotic use, where antibiotics are given to all the
animals in a farming unit, can help to prevent outbreaks of disease. However, it
should not be used to make up for poor hygiene practices or inadequate housing.
ITQ 8
How are prophylactic ‘routine’
antibiotics administered?
antibiotic growth promoter ▶
hormone use ▶
Routine use of antibiotics to combat infections caused by poor hygiene practices
are ineffective and have been banned in many countries, including the whole
of Europe. Misuse of antibiotics is helping to generate antibiotic resistance.
Antibiotic resistance is the situation where the bacteria that cause the infection
mutate and survive the antibiotic treatment. When an antibiotic is used, bacteria
that can resist that antibiotic have a greater chance of survival than those that
cannot resist it, and those bacteria that are not killed multiply quickly. Bacterial
infections that do this are often called ‘super-bugs’. Some resistance occurs even
without human action, as bacteria can produce and use antibiotics against other
bacteria, leading to a low level of natural selection for resistance to antibiotics.
However, the current higher levels of antibiotic-resistant bacteria are thought to
be the result of the overuse and abuse of antibiotics.
An antibiotic growth promoter is any medicine that destroys or inhibits
bacteria and that is given at a low, sub-therapeutic dose. A sub-therapeutic dose
is a dose that is less than the amount needed to treat the disease. The use of
antibiotics to promote growth has occurred with the intensification of livestock
farming. Use of growth promoters in farm animals is common throughout the
world, although growth promoters were banned in the EU in 2006, which makes
export to some countries difficult. The ban includes low-dose antibiotics, which
are still used in many countries globally to increase growth rates in animals.
All mammals produce hormones naturally, so all animal products will contain
some hormones. It was discovered in the 1950s that naturally occurring growth
hormones could increase the feed conversion efficiency (FCE) of animals. This
led to the development of synthetic growth hormones that would have the same
effect as natural growth hormones. Hormone use improved the conversion of
feed to lean meat. Beef cattle and sheep are the farm animals most commonly
given growth hormones. There is a 5–20% overall increase in productivity from
animals that are given them.
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Section E: Farm management technologies
23.5 Control measures for pests and diseases
Pest and disease prevention control
isolation ▶
quarantine ▶
Isolation
If an animal is suspected to have a contagious infection it should be put in
isolation to prevent the infection spreading to other animals, and to allow the
animal to rest and recover during the treatment.
Quarantine
The most likely way for disease outbreaks to occur on a farm is through the
arrival of new animals or the return of the farmer’s animals from elsewhere.
Quarantine protects animals already on the farm against disease by keeping the
arriving animals separate from the other animals on the farm for a period, or until
the farmer is certain the new arrivals are not carrying diseases.
Areas used for isolation and quarantine should:
• be as far as possible from all other animals
• be completely separate buildings with separate airspaces and double-fenced
grazing areas
• use separate equipment, if possible
• have separate feed, water, drainage supplies and bedding
• be adequately lit so that the animals can be inspected properly
• have disinfectant footbaths placed at the isolation area entrance to make a
barrier to disease. Footbaths should be kept clean and topped up regularly
with approved disinfectant at the correct dilution. They should also be covered
to protect them from dilution by rainwater or contamination.
ITQ 9
What is the difference between
isolation and quarantine?
Day-to-day management of animals in isolation or quarantine
All farm staff should be fully aware of recommended separation procedures.
The best practice is to use different staff to manage the quarantined and nonquarantined animals. Where it is not possible to use separate employees, the
following procedures should be carried out.
• Use separate personal protective equipment.
• Tend to the isolated and quarantined animals last, after the healthy animals.
• Always disinfect or change personal protective equipment after the tending
routine is complete.
• Inspect animals in quarantine regularly and look closely for signs of disease.
• If signs of disease are seen, contact the vet immediately regarding diagnosis,
treatment and future management.
• Inspect animals in isolation regularly, monitor closely and report progress to
the vet.
• Take care when handling and disposing of contaminated bedding, waste and
feed.
Biosecurity measures
Disease control through biosecurity measures focuses on controlling and reducing
movements of animals, people and vehicles to and from areas where livestock is
kept.
biosecurity measures ▶
330
Biosecurity measures can help to prevent the spread of farm diseases. They also
protect agricultural workers and visitors. There are different levels of biosecurity
procedures for animals on farms, and for animals being moved, for example, to
markets and agricultural shows.
23: Management practices for livestock
On-farm biosecurity measures include:
• cleaning and disinfecting protective clothing and vehicles before and after
contact with animals
• using disposable protective clothing.
During an outbreak of a serious disease, such as foot and mouth disease, the
following biosecurity measures should be used:
• banning vehicles, equipment and clothing contaminated with animal
excreta, except vehicle interiors and protective clothing taken off the farm
for laundering
• cleaning contamination from clothes before leaving animal areas
• cleaning and disinfecting boots before leaving animal areas.
Keep animals that cannot develop the disease, such as dogs and wild animals,
away from the farm as these animals may become carriers and transmit the
infection to the healthy stock.
Figure 23.8 Vehicle drive through dips
are used to disinfect vehicles.
Make sure that animals that die on the farm (deadstock) are removed to be
incinerated (burned) to prevent the spread of the disease. If the animals cannot be
incinerated, deadstock should be buried at least 50 m from a watercourse, where
the grave will not be disturbed. This is to prevent the infection that killed the
animal from infecting the rest of the livestock or the farmer through contaminated
water.
Prophylactic use of antibiotics
Prophylactic or routine use of antibiotics (as discussed in Section 23.4) is one
method of preventing disease from spreading around livestock units.
deworming ▶
Deworming
Deworming, also known as worming or drenching, is the process of giving an
anthelmintic drug (a dewormer or drench) to a person or animal to get rid of
helminth parasites, such as roundworm, flukes and tapeworm. Purge dewormers
for livestock can be given as a feed supplement, a paste or gel that is deposited at
the back of the animal’s mouth, a liquid drench that is given orally, an injection
or as a pour-on that can be applied to the animal’s topline.
Spraying livestock
Parasiticides are sprayed on livestock such as cattle, sheep, goats, pigs and poultry
to protect them against external parasites such as flies, ticks, mites, lice, mosquitoes
and fleas. For cattle and sheep on small farms, spraying can be done instead of
plunge dipping if the farms do not have the equipment for dipping. Livestock that
are housed indoors need to be sprayed regularly to keep the parasites away.
Figure 23.9 Boar with fly infestation.
Vaccinations
Vaccines are given to animals to prevent diseases. They are part of a category of
animal medicines known as veterinary biologics, which work by stimulating an
animal’s immune system to prevent or treat diseases. Vaccinating animals reduces
animal suffering and reduces the transmission of micro-organisms in the animal
population. It is often cheaper to vaccinate the animals than it is to treat the
animals when they get sick.
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Section E: Farm management technologies
Practical activities:
Visit a veterinary practice.
1. Make a note of the most
common diseases that vets
have to deal with.
2. Find out which aspects of
animal management can
reduce both the severity and
the spread of each infection.
Livestock animals such as turkeys, chickens, cattle and pigs are vaccinated
to protect against diseases such as rotavirus, E. coli, pinkeye and brucellosis.
Vaccinations keep individual animals, flocks and herds healthy.
23.6 Biotechnology in animal production
Concept of biotechnology
Biotechnology is an area of biology that uses living systems and organisms to
develop, make or modify products. Biotechnology in agricultural science includes
genetic modification, which is the alteration of specific pieces of DNA to improve
certain traits for the purpose of increased or improved food production. Modifying
livestock genetically is still at a research stage. This is the process where animals
are genetically modified to improve their yields or increase their resistance to
particular diseases.
Biotechnology has made rapid progress in the last few years, although each
biotechnology breakthrough requires licensing before it can be used in food
production.
Figure 23.10 Livestock feed troughs.
ITQ 10
State FOUR pieces of information
that can be obtained from sensors
on cattle.
Biotechnology for monitoring livestock is frequently used in the following ways.
• Data boluses: These are microchips or sensors that are swallowed by cattle
(but not passed through the animal) and used to monitor all the health signs,
particularly the volume of water drunk, the temperature of an animal and
the acidity of the gut. This information helps the farmer understand how
efficiently food is being converted by an animal. The data can be downloaded
on the farmer’s computer, along with software to help him or her understand
whether an animal needs medicine or veterinary support.
• Sensors used for monitoring beef fattening, placed on a tag around the neck:
Feed troughs are positioned so that only one animal can access them at a
time. The trough sits on a weighing scale. The animal’s sensor reads the
starting and finishing weight of the trough and automatically calculates the
weight of the feed each animal consumes.
Methods of biotechnology
Genetic engineers must isolate the gene they wish to insert into the host organism.
This can be taken from a cell containing the gene or it can be made artificially. If
the chosen gene, or the donor organism’s genome, has been previously studied,
it may already exist in a genetic library. The gene is then combined with other
genetic elements, including a promoter, terminator region and usually a selectable
marker.
A number of techniques are available for inserting the isolated gene into the host
genome. With animals, DNA is generally inserted using microinjection, where it
can be injected through the cell’s nuclear envelope directly into the nucleus. The
first transgenic animals were produced by injecting viral DNA into embryos and
then implanting the embryos in females.
The inserted DNA must be present in the embryonic stem cells so that as the
embryo develops, some of the genetic material is incorporated into the reproductive
cells. Researchers then wait until the animal reaches breeding age to screen the
offspring for presence of the gene in every cell, using polymerase chain reaction
(PCR), southern hybridisation or DNA sequencing.
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23: Management practices for livestock
New technologies are making genetic modifications easier and more precise.
Gene targeting techniques, which create double-stranded breaks, takes advantage
of the cells natural homologous recombination repair systems, and have been
developed to target insertion to exact locations.
Genome editing uses artificially engineered nuclei that create breaks at specific
points, so the gene sequence is cut precisely, so that the modified genetic material
can be inserted accurately. The development of the CRISPR-Cas9 gene editing
system has effectively halved the amount of time needed to develop genetically
modified animals.
Benefits of biotechnology in livestock
Practical activity:
Organise a debate on the role
of biotechnology. Alternatively,
prepare group presentations on
different aspects of biotechnology
and how it can be applied to
farming in the Caribbean.
The general benefits include:
• improved productivity; there is increased growth in animals reared for food
• the production of hormones and other substances in milk
• the ability to carry out research into the transplantation of cells, tissues and
organs from one species into another species
• improved properties in those crop plants used in the manufacture of animal
feeds.
At present, improved productivity in animals used for food is the only benefit
that directly affects consumers. Many other aspects of this technology are at the
research stage.
Concerns about the use of biotechnology
ITQ 11
Suggest TWO concerns about the use
of animals in genetic engineering.
Concerns have been expressed about:
• the failure of treated embryos to survive
• the failure of introduced genes to be transferred
• the long-term effects of animal clones
• the introduction of genes causing animals to behave abnormally: transgenic
animals may suffer from ill health
• the suffering caused to animals during the surgical removal of embryos and
embryo transfer.
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Section E: Farm management technologies
Revision map
Animals
sprayed or dusted
to remove external
parasites
Feeders,
waterers and
stalls cleaned
daily
Takes place
in an enclosed area
where they are housed,
protected, fed and
kept warm
Taking care
of day-old chicks
for 2–3 weeks
Kindling in
nest box in
hutch
Sanitised
pens and
stalls
Can be done
naturally by the
hen or artificially
using incubators
Poultry
brooding
Animals given
antibiotics to
prevent the spread
of disease
Good
agricultural
practices
Caring for
young farm
animals
Rabbit
brooding
Spraying
Clean
housing
Most young
animals are cheaper
to buy than adult
animals (required
to maintain
stocks)
Pastures
sprayed to
control
parasites
Sick animals
isolated and
treated
Kittens leave
nest box after
3 weeks
Biotechnology
is the use of living
systems and organisms
to develop, make or
modify products
Genetic
modification involves
altering DNA to improve
certain traits; used
to improve
production
New arrivals
quarantined
Management
practices for
livestock
Biosecurity
measures used to
control disease
Foundations
Biotechnology
in animal
production
There are
some concerns
about the use of
biotechnology
Walls
Livestock
housing
Suitable local
and imported
materials used for
specific purposes
Lighting
Location
Roofs
Safety
Design
factors
Purpose
Housing for
broilers and
layers
Housing
for rabbits
Security
Orientation
Ventilation
Battery
systems –
wire cages with
sloping floor
egg retrieval
Deep litter
systems –
pens with litter
and sometimes nest
boxes and perches
Sanitation
334
Floors
Hutches
constructed of
wire mesh
Constructed of
wood and wire mesh
if hutches are
outdoors
23: Management practices for livestock
Examination-style questions
Multiple-choice questions
Write down the number of the question followed by the letter of the correct answer.
1.
2.
3.
4.
Which of the following is a NOT a suitable construction material for the foundations of an animal house?
A Concrete
B Lumber
C Bricks
D Steel rods
What is the recommended stocking density per m2 for layers kept in a deep litter system?
A 2
B 3
C 4
D 5
Which of the following should be managed in the care of chicks?
A pH
B Temperature
C Soil type
D Sound
Deworming helps rid the animal of worms and which of these parasites?
A Fleas
B Flies
C Ticks
D Flukes
Short-answer and essay-type questions
5.
(a)Complete the table, naming TWO other local / regional construction materials in each grouping.
Grouping
Lumber (wood)
Metal
Clay / concrete
PVC
Aggregates
6.
Examples: local / regional construction materials
teak,
steel rods,
tiles,
fittings,
sand,
(b) List FOUR construction materials (lumber, metal or any other grouping) imported from countries outside the Caribbean.
(c) Describe the properties of the following construction materials:
(i) Lumber (wood)
(ii) Iron / steel
(iii) Concrete
(a) State THREE names for each of the following:
(i) Local / regional lumber (wood or board)
(ii) Imported lumber
(b) Complete the table, naming THREE suitable construction materials for each of the specified areas of the farm building:
Part of farm
building
Foundation
Floor
Wall
Roof
Names of three suitable construction
materials
7.
(a) Describe the materials used in the construction of rabbit hutches.
(b) Describe and explain the features of rabbit hutches.
8. Biotechnology will benefit all farmers. State if you agree or disagree, then explain your views using information from internet research and
your own observations of farming in the Caribbean.
9. Describe the biosecurity measures that could be used on a farm with poultry, cattle and sheep.
10. Explain how good agricultural practices prevent the spread of disease in livestock.
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Section E: Farm management technologies
24
Harvesting,
post-harvesting
management and
value addition
By the end of this unit you should be able to:
✔
✔
✔
✔
✔
Concept map
Harvesting, post-harvesting management and value addition
Correct stage
for harvesting
Post-harvest
management system
Maturity
Maturity indices
Physiological
Horticultural / Commercial
Harvest
Harvesting procedures
Time of day
Manual / Mechanical methods
Removal of the crop
Harvesting technology
Techniques in manual harvesting
Harvesting aids
3-point bulk loader
Self-propelled bulk loader
Field packaging equipment
Containers
Handling
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determine the correct stage for harvesting crops
recommend appropriate harvesting procedures
design a post-harvest management system
implement proper post-harvesting procedures
recommend processes for adding value to the crop produced.
Advantages
Maintaining crop quality
Reducing crop losses
Careers
Consumer safety
inspectors
Food inspectors
Refrigeration engineer
Procedures
Transport from the field
Humidity management
Sanitation
Minimising of damage
Curing
Sorting of damaged or
diseased produce
Field or market storage
Differences in crop requirements
Implementation of
post-harvest procedures
Post-harvest equipment
Entrepreneurship
Processes for adding
value to produce
Minimal processing
Packaging
Product transformation
Freezing
Preservation
Labelling
Grading
24: Harvesting, post-harvesting management and value addition
24.1 Correct stage for harvesting
Maturity
The farmer uses a plant’s maturity to decide the exact moment or stage to pick a
crop. The stage at which the crops should be harvested is vital to the quality of the
product. Good quality is achieved when harvesting is done at the proper stage of
maturity. If fruits are harvested before they have matured properly, they may not
ripen completely and may not develop enough flavour. Crops that are harvested
too late (over mature) will have a shorter shelf-life and will spoil easily.
Maturity indices
Maturity indices are measurements that can be used to decide whether a particular
fruit or vegetable is mature and ready to be harvested. Maturity can be decided by
subjective or objective observation.
These observations often include:
• physical methods: for example, observing size, shape, colour and texture
• chemical methods: for example, measuring the amount of sugar (starch) in
produce, as the amount of starch increases with maturity; and measuring the
acidity, as organic acids decrease as the fruit ripens
• physiological methods: for example, measuring respiration, as it peaks when
fruits or vegetables reach maturity; and measuring ethylene production, as the
quantity of this hormone increases as fruit ripens, particularly in fleshy fruits
such as tomatoes, apples, melons and bananas.
Other measures that can be used include the natural detachment of parts of the
plant (such as leaves and fruit), duration after flowering, firmness, dry matter,
juice content, oil content and waxiness or tenderness. These can all be used to
determine a date for harvest.
senescence ▶
dehisce ▶
Physiological maturity
This refers to the stage in the development of the fruits and vegetables when
maximum growth and maturation has occurred. The fruits are usually fully ripe
at this time. The physiological mature stage is followed by senescence, which
is when cells stop dividing and a fruit starts to get worse with age. For example,
French bean pods or ochro are physiologically mature when their seeds are fully
developed and the pods will dehisce (burst open) with little pressure.
Horticultural / Commercial maturity
Horticultural maturity refers to any stage of development when the commodity
has reached the level of development needed for its intended use. It is sometimes
called commercial maturity. For example, a papaya with green pulp and peel that
has reached its maximum size is already commercially mature as a vegetable, but
must develop a tinge of yellow colour for it to be sweet enough to be used for
dessert.
Harvest maturity
This is a combination of physiological and commercial maturity. It is a stage
where the fruits / vegetables are at their peak condition. When they reach the
consumers, they have an acceptable flavour or appearance and will have a good
shelf-life. For example, farmers will harvest fully coloured tomato fruits for local
markets and for processing. However, for a distant market, the farmers will need
to harvest the tomato fruits that have only just started developing colour.
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Section E: Farm management technologies
ITQ 1
List the THREE maturity indices that
determine the timing of harvesting.
Give an example of each index.
The maturity of fruit at harvest will greatly affect their quality all along the
value chain after harvest. Farmers need to apply accurate, efficient and effective
maturity indices to ensure that there is high quality at all levels along the value
chain. Farmers cannot use a single maturity index to determine the maturity of
fruits. They need to use different parameters to make accurate decisions. There
are slight differences in maturity among the cultivars of the same crop, so different
indices need to be used.
24.2 Appropriate harvesting procedures
Time of day
Figure 24.1 Mature bell pepper ready to
be picked for local market.
The best time to pick fruit and greens for salads is early in the morning, before or
around sunrise. This ensures that the produce is still cool and will stay crisp and
dew-covered from the night. Other fruiting vegetables, such as tomatoes, peppers
and cucumbers are less sensitive to wilting, so they can be picked later in the day,
as can root vegetables such as carrots. However, these items need to moved out of
the sun and into the refrigerator or a cool place quickly, particularly if the weather
is warm.
Manual and mechanical harvest methods
Manual harvest
• Used for cocoa, coffee, bananas and yams
• Methods include hand-picking (cocoa and coffee),
uprooting, cutting using a knife or a cutlass (bananas)
and digging out with a fork (yams)
• Used for fields that are not accessible to machinery
• Used for crops grown in small plots or nurseries,
using multiple cropping or intercropping systems
• Time-consuming
• Labour-intensive
Mechanical harvest
• Combine harvesters used for grain
crops
• Specialised harvesting equipment
used for sugar cane and sweet potato
• Requires large, flat fields that
equipment can be turned around in
• Saves time as it gathers crop quickly
• Less manual labour required
Table 24.1 Manual and mechanical harvest methods.
Figure 24.2 Immature coffee beans.
Removal of the crop
ITQ 2
Careful harvesting, handling and transporting of fruits and vegetables from the
field is necessary to preserve product quality.
State TWO advantages of mechanical
harvesting.
ITQ 3
Give TWO examples of manually
harvested crops and state the
method used for each example.
Polythene bags
Clear or blue polythene bags are used to pack banana bunches in the field.
The packed bags are then transported to the packing house from the banana
plantation. This technique of packaging bananas reduces damage to the fruit
caused by improper handling.
Plastic field boxes
These are durable containers that can last many years. Many containers are
designed so that they can be stacked one on top of the other without crushing the
produce when they are full. They can nest inside each other when they are empty
to make them easy to transport.
Wooden field boxes
These boxes are made of thin pieces of wood bound together with wire. They
come in two sizes: the bushel box with a volume of 36 000 cm3 and the half-bushel
box. The boxes are cheap, can be packed flat and are non-returnable. However,
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24: Harvesting, post-harvesting management and value addition
they do not protect the produce very well during transport. Rigid wooden boxes
of different sizes are commonly used to transport produce to the packing house
or to market.
ITQ 4
List THREE types of packaging that
can be used to carry a crop from
the field.
Bulk bins
Bulk bins that can hold 200 –500 kg are used for harvesting fresh fruits and
vegetables. These bins are much more economical than the field boxes in terms
of the amount of produce they can hold and their durability. They also protect
the produce better during transport to the packing house. They are made of wood
and plastic materials. The depth of a bulk bin depends on the type of fruit or
vegetable being transported.
24.3 Appropriate harvesting technology
Techniques in manual harvesting
The most important advantage of manual harvesting is that the workers can
quickly detect the fruit that is ready for harvest and then harvest that produce.
Because the designers of mechanical harvesters did not have computer-based
image-processing equipment, they designed equipment that could harvest the
produce using a mass-removal approach. This method often results in more
damage than when the fruit is harvested individually. Although manual harvesting
has the disadvantage of being slow, it is expected that much of the world’s fruit
will continue to be harvested by hand for the foreseeable future.
Harvesting aids
Harvesting aids are used wherever they are economically productive. They are
usually owned by large farms or a cooperative.
three-point bulk loader ▶
self-propelled bulk loader ▶
ITQ 5
Using an example, explain why
harvesting aids are used.
field packs ▶
The three-point bulk loader is towed by a tractor on a three-point linkage. (The
three-point linkage is described in more detail in Unit 26.) The self-propelled
bulk loader has an engine and a cab, so it does not need to be towed.
The bulk loader travels along tramlines while the labourers pick the produce
and put it directly onto the conveyer belt. Bulk loaders reduce harvesting costs
because less labour is needed. They also reduce the loss on products such as
tomatoes, lettuces, bell peppers, strawberries and cantaloupe melons. The benefit
of the bulk loader is that the soft produce does not have to be placed in boxes
where it can be squashed by any produce that is placed on top or damaged when
the boxes are loaded onto transport. There is also a trash belt that can remove
poor-quality produce straight away so that it is never mixed with the commercial
harvest. Management practices and plantings can be planned around the use of
this machine. The bulk loader is usually manufactured entirely of stainless steel
to meet food safety requirements and to meet programme specifications such as
good agricultural practices (GAP).
In the field, workers can place the produce on to the conveyor belt where it can be
moved through an optional wash tank or spray chamber. From there the product
is moved to the packers where it is packed by size and weight. The produce is then
loaded on a transport trailer. Field packs create a very clean product that has
very little or no bruising. Field packs reduce the product loss, increase the packout rates (packaging to market) and improve product quality.
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Section E: Farm management technologies
Choice and handling of containers
Perishable (fruit
and vegetable
crops)
Durable
(cereal crops)
Field handling
Field handling
Delivered to a
storage / handling
area
Threshing / shelling
Conveying
Delivered to a
storage / handling
area
Cleaning
Pre-cleaning
Sorting
Drying
Grading
Storage
Treatment
Transport
Packaging
Delivered to a
storage / handling
area
Unitisation
Preventing post-harvest food losses is very important in the production of soft
fruit and vegetables. This is why it is essential to pack the harvest into the correct
type of container. Nowadays, commercial growers pack produce directly from the
harvest in the field into the packages in which the products will be sold because
this will reduce the damage caused by handling.
24.4 Post-harvest management systems
Post-harvest management is the term used for the systems that manage the stage
of crop production immediately following the harvest. The processes include the
cooling, cleaning, sorting and packing of produce. The moment a crop is removed
from the ground or separated from the parent plants, it begins to go down in
quality. Post-harvest management works to improve and maintain the quality of
the produce and extend its shelf-life, so the produce has more chance of being
sold to consumers before its quality becomes too low to pass acceptable standards.
Figure 24.3 shows the sequence of operations that both perishable and durable
products must pass through before they reach the consumer. Each operation
needs to be planned as part of the post-harvest management system.
Advantages of a post-harvest management system
Cleaning
Storage
Treatment
Dispatch
Storage
Transport
Processing
Maintaining crop quality
Maintaining crop quality is vital. There are quality standards that products
must meet and the consumers also expect a certain level of quality. Consumers
may expect a particular colour, scent or feel and these expectations are closely
connected to a consumer’s opinion of value. Consumers consider quality, quantity
and price when they decide whether a product is good value or not.
Wholesaling
Retailing
Retailing
Consumption
Consumption
Figure 24.3 Sequence of operations for
perishable and durable produce.
Reducing crop losses
Product is lost throughout the farming process, from the planting of seeds through
to the final sale of produce to the consumer. Aside from catastrophic losses caused
by hurricanes and drought, the greatest loss of food products occurs after the
produce has been harvested. A good post-harvest management system will
extend the amount of time that can be taken from harvest to consumer. This will
allow more time for the product to be displayed in a supermarket and increases
the possibility that it will be bought by the consumer.
Procedures in a post-harvest management system
Transport from the field
Harvested crops need to be transported from the field in suitable containers and
then packed into suitable vehicles to extend the shelf-life of the produce as much
as possible. Although many farmers may plan to use boxes or sacks and load them
onto pick-up trucks because this is a cheaper way to handle a harvest, they should
be aware that produce packed into moulded crates and transported in refrigerator
trucks will have a longer shelf-life and be available for sale to the consumer for a
longer period, thus increasing the sales and profit.
Humidity management
The storage used immediately after the produce has been harvested plays a
very important part in maintaining the quality of the produce. Each crop has
an optimum range of storage temperature and humidity. Also, certain crops
should not be stored together, because unwanted chemical interactions can
result. Keeping the product cool can slow down these chemical changes. Various
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24: Harvesting, post-harvesting management and value addition
methods of high-speed cooling and refrigeration and atmosphere-controlled
environments are used to keep the produce fresh for a longer time, particularly
in large operations.
Sanitation
Good sanitation reduces food safety risks in fresh produce operations. Using good
post-harvest practices will also help to maintain produce quality and reduce postharvest decay.
Any surface that the produce touches could be a source of contamination. Such
surfaces include equipment, belts, rollers, brushes, tables, bins, sinks, tools and
even the hands of the workers. Surfaces that touch produce must be easy to clean
and possibly sanitise.
Contamination of harvested produce can be avoided by not placing the produce
directly on the soil, especially wet soil, using clean field containers, and preventing
contact with oil or other chemicals unless they are part of the post-harvest
treatments.
ITQ 6
Explain why sanitation is an
important part of the postharvest plan.
Surfaces can be sanitised using the following method.
1. Rinse the surface to remove any visible dirt and debris.
2. Apply a suitable detergent and scrub the surface.
3. Rinse the surface with water that is as clean as drinking water (this is called
potable water).
4. Apply a suitable sanitiser and rinse off if necessary.
5. Let the surface air dry.
Minimising damage
Workers need to be trained in ways to evaluate the readiness of the crop for
harvest and be able to reject unsuitable produce at harvest, according to market
requirements.
Workers also require training in:
• appropriate techniques for harvesting produce, for example, breaking the
stem, plucking, clipping, cutting or digging
• the use of harvest containers and the transfer of produce to field or marketing
containers to prevent wooden containers with rough edges, splinters,
protruding nails or staples damaging the produce
• the general care of the produce during packing so that produce is not dropped
or thrown into containers from a distance, and the containers are not
overfilled
• how to handle full containers with care so that they can be moved and
stacked without damaging produce.
Supervisors should check the staff for long fingernails or jewellery that could
damage the produce.
Curing
Curing produce after harvest is an effective way to reduce water loss and decay
during post-harvest storage of root, tuber and bulb crops. In root and tuber crops,
curing is the process of wound healing with the development of new epidermal
tissue called wound periderm.
In bulb crops, curing refers to the process of drying the neck tissues and the outer
leaves to form dry scales. Some water loss takes place during curing. Removing
decayed bulbs before curing and storage ensures there will be a greater percentage
of usable product after storage.
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Section E: Farm management technologies
When onions and garlic are cured in the field, they are undercut and then hand
pulled. Sometimes the roots and tops are trimmed and the bulbs are allowed to
dry in field racks or bins for 2–7 days, or longer, depending on the field conditions.
Curing may be done in windrows with the tops covering the bulbs to prevent
sunburn. Where the environmental conditions are unsuitable, curing may be
done in rooms with warm, forced air. Onions develop the best scale colour if they
are cured at temperatures of 25–32 °C.
Sorting of damaged or diseased produce
Produce needs to be sorted so that all the harvested produce receives the correct
application of post-harvest treatment, for example, fungicide or wax coating.
This is particularly important where produce is packed on the farm directly into
marketing packages for export or supermarkets.
Fruits and vegetables are living parts of a plant and they are 65–95% water. When
the food and water reserves are used up, the produce dies and decays. Anything
that increases the rate at which a product’s food and water reserves are used up,
increases the possibility of post-harvest losses.
Damage to produce
Cuts or punctures
Impact (shock)
Compression (squeezing or
squashing)
Vibration (shaking)
Heat damage
Cause of damage
• Sharp objects piercing package
• Splinters in bamboo or wooden containers
• Staples or nails sticking out in containers
• Packages thrown or dropped
• Vehicle starting or stopping suddenly, causing load
movement
• Speeding vehicle on rough roads
• Weak or oversized containers
• Containers overfilled or stacked too high, or both
• Collapse of stacked containers during transport
• Vibration of the vehicle itself and from rough roads
• Exposure of packages to external heat, e.g. direct
sunlight, or storage near heating system
• Natural build-up of internal heat of produce as a result
of poor ventilation within the package, in storage or in
the vehicle
Chilling or freezing damage
• Low or sub-zero environmental temperatures
• Exposure of sensitive produce to temperatures below
chilling or freezing-tolerance level during storage
Moisture and free-water damage
• Exposure to rain or high humidity
• Condensation on packages and produce moved from
cold store to damp atmosphere at environmental
temperature
• Packaging of wet produce in cardboard containers
• Plastic sacks and crates that have not been treated to
protect them from ultraviolet eventually breaking up
when they are exposed to direct sunlight
Damage from light
Chemical contamination
342
• Contamination of containers stored near chemicals
• Damage to produce by containers treated with
preservatives
Effect of damage
• Deep punctures or cuts in produce, leading to water
loss and rapid decay
• Burst packaging
• Bruised contents
• Bruised or crushed contents
• Wooden boxes come apart, damaging produce
• Fruit becomes overripe or softens
• Produce wilts and develops unpleasant flavours
• Decay develops rapidly
• Cardboard cartons may become dry and brittle, and
easily damaged on impact
• Damage to chill-sensitive produce
• Breakdown of frozen produce on thawing
• Plastic containers become brittle and may crack
• Softening and collapse of stacked cardboard
containers
• Squashed produce in collapsed containers
• Decay promoted in damaged produce
• Plastic sacks disintegrate and damage produce when
they are moved
• Plastic crates that fracture can cut or bruise produce
• Flavour contamination or surface damage and
discoloration of produce in contact with the container
• Decay of produce owing to contaminating moulds
• Wood-rotting moulds cause collapse of boxes
24: Harvesting, post-harvesting management and value addition
Damage to produce
Insect damage
Cause of damage
• Insects present in packed produce
• Wood-boring insects in wooden boxes
Human and animal damage
• Stealing by people
• Contamination and consumption by rodents and birds
Effect of damage
• Consumer resistance and legal problems from
presence of insects (e.g. spiders, cockroaches) in
packed produce
• Spread of wood-destroying insects in infected boxes
• Rejection of damaged produce by buyers or inspectors
• Loss of income through loss of produce
Table 24.2 Damage that can affect produce, how each type of damage is caused and the effect of the damage.
ITQ 7
Describe how heat can damage a
crop after harvest.
ITQ 8
Explain why post-harvest
management plans have storage
procedures that need to be followed.
Field or market storage
Produce may be carried by trucks in palletised field containers, bulk bins or in
hand-loaded sacks or wooden or plastic boxes. If a vehicle has to wait in the sun
or rain for long periods before it is unloaded, only the top part of the load should
be protected by a covering. Grass or leaves are not recommended for this purpose
because they restrict ventilation and may be a source of disease. The load should
not be completely enclosed with a tarpaulin either because a tarpaulin restricts
ventilation causing the temperature of the produce to rise rapidly, which could
spoil the produce.
Differences in crop requirements
Different crops have different requirements for post-harvest care.
Climacteric fruits are fruits that have higher levels of ethylene as they ripen, for
example, avocados. These fruits should not be stored near ethylene-sensitive
crops, such as broccoli, celery or watermelons, or any unripe climacteric fruits
that the farmer wishes to keep from ripening.
Non-climacteric fruits include citrus, grapes, strawberries, peppers and
watermelons. These fruits will not be affected if ethylene is released near them.
Blueberries are climacteric; however, blueberries must ripen fully on the plant to
achieve an acceptable, sweet flavour.
Some crops are sensitive to chilling, including tomatoes, peppers, squash,
eggplants and citrus fruits. Injuries from chilling include pitting, surface decay,
internal browning and surface scald. The fruits will also have poor flavour, aroma
and colour. Potato tubers intended for the fresh market are very easily affected by
bacterial soft rot if they are stored at normal late-spring or summer temperatures.
To avoid this, the tubers should be chilled.
Practical activity:
Assess a selection of crops that have been harvested.
Use a table such as the one shown here to decide what sort of damage the produce has been exposed to, and state the effect of the
damage on each product.
Product
e.g. Tomato
Post-harvest damage to product
Some bruising and discolouration
Effect of damage on product
Bruising will spoil flavour, less likely to be purchased,
shorter shelf-life before product goes bad.
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24.5 Proper post-harvesting procedures
Crop
Tomato
Sweet potato, yam,
cassava, dasheen
Apple
Mango
Leafy green vegetable
e.g. spinach
Specific post-harvesting procedures
Should be harvested in early morning, while fruit still green, and dipped
in water to cool further. Sorted to eliminate damaged or overripe fruit and
graded by colour so that slightly riper fruit will not produce ethylene that
will ripen the whole batch. Ripe tomatoes should be stored at 10 – 15 °C.
Temperatures lower than that will cause chilling injuries because of the
tomato’s high water content.
Requires curing. Can be stored for 3–10 months using ventilated storage.
The produce is sensitive to chilling. Needs dry brushing or washing but
must be dried before storage or the produce will spoil quickly.
Boxes must not be overfilled. Produce needs to be dipped or sprayed with
surfactant and fungicide. (A surfactant is used to make pesticides more
effective, for example, a ‘sticker’ will make a liquid fungicide spray ‘stick’
to the fruit and not run off in the rain.) Produce is cooled quickly using
air forced into boxes or hydro-cooled in the water containing the dip. The
apples must not be allowed to warm up and then be re-chilled because
this leads to ‘sweating’ (droplets of water on the surface of the fruit),
which encourages the growth of moulds.
Picked when still firm and graded. Grading is vital; large fruit takes
2–4 days longer to ripen than smaller fruit does. If the smaller fruits
are mixed in with the larger fruits, they will cause early ripening and
decay. Fruit should be pre-cooled to 10 – 12 °C. Keeping fruit in ventilated
polythene bags will prevent chilling injuries.
Handpicked; selected for maturity and quality. Trimmed, sorted, graded
and packaged in the field to reduce mechanical damage. Transported to
cold storage with minimal air circulation to prevent slow decay. Ethylene
must be avoided as this will cause decay. Spinach, which perishes
very easily, does not tolerate a low oxygen atmosphere and is routinely
washed and packed in ventilated polythene bags.
Table 24.3 Specific post-harvesting procedures for common tropical crops.
Post-harvest equipment
The most important processes are crop drying and dry storage. These processes
aim to minimise the rate of metabolism of harvested produce and control postharvest pests and diseases. Post-harvest operations generally cannot improve
quality, although waxing apples to make them shine more may be considered
an improvement. The equipment used will depend on the produce harvested, for
example, fillers, sieves and strainers would be used to turn harvested pineapple
into pineapple juice.
24.6 Processes for adding value to the
crop produced
Minimal processing
Minimally processed products, also known as ‘ready-to-eat’ fruits and vegetables,
have increased in popularity in the past few years because of consumer lifestyles.
Sustainable farming success depends on satisfying consumer requirements.
However, fresh fruits and vegetables perish easily and any losses will reduce a
farmer’s profit. The quality of fresh produce cannot be improved by post-harvest
technologies, only maintained. This means these products must be of a high
quality at harvest. Ready-to-eat fruits and vegetables need more care to preserve
their quality throughout their shelf-lives.
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Packaging
The package must protect the produce from mechanical damage and poor
environmental conditions during handling and distribution. Consumers will see
torn, dented or collapsed produce packages as signs of a lack of care in handling
the contents. Produce containers must be sturdy enough to resist damage during
packaging, storage and transportation to market.
Almost all produce packages are transported on pallets, so produce containers
must have enough stacking strength to resist being crushed in a low-temperature,
high-humidity environment.
ITQ 9
State THREE functions of a good
produce container.
Damage as a result of poor environmental control during handling and transport is
one of the main reasons that produce gets rejected and consumers are unsatisfied.
Each fresh fruit and vegetable commodity has its own requirements for
temperature, humidity and environmental gas composition. Produce containers
should be designed to maintain an optimum environment for the produce in
them so that the produce will have a long shelf-life. This may include special
materials to slow the loss of water from the produce, insulation materials to keep
out the heat or engineered plastic liners that maintain a favourable mix of oxygen
and carbon dioxide.
Product transformation
Transforming fresh produce as soon as it is harvested is a good way to reduce
losses from overripe fruit. The sooner the product can be transformed following
harvest, the better the quality of the transformed product will be.
Freezing
Freezing retains the quality of products over long storage periods. As a method of
long-term preservation for fruits and vegetables, freezing is generally regarded as
superior to canning and dehydration. The extreme cold simply stops the growth
of micro-organisms and slows down the chemical changes that affect quality
or cause food to spoil. The safety and the nutritional quality of frozen products
are improved when high-quality raw materials are used, good manufacturing
practices are followed in the preservation process and the products are kept at
the correct temperature. The freezing process is one of the most convenient and
easiest of food preservation methods.
Preservation to create products, for example, flour or chips
Cassava, for example, produces a gluten-free flour, which can be used as composite
flour in essential foods such as bread. Cassava root spoils rapidly after harvest. The
post-harvest processing into high-quality flour and other food forms such as fufu,
garri and starch prevents losses from decay and aids long-term storage.
Labelling
Labels on food can add value to the product by describing appropriate storage
methods to use and recommended storage temperatures. Foods also have
nutritional labelling, informing the consumer exactly what is in the product and
the energy value in kilojoules that it will provide. Sell-by dates and consumeby dates (best-before dates) inform both the retailer and the consumer about
appropriate storage periods.
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ITQ 10
Using examples, explain how
product transformation can add
value to a product.
Practical activity:
In groups, select an item of produce
and suggest ways to make a valueadded product.
Create a poster explaining how you
will make your product and bring it
to market. If you have the resources
available, make the product.
Grading
Grading adds value to fresh produce as it prevents the unplanned ripening of
products that are badly packed together. Grading is a vital step in preventing postharvest losses, as batches of fruit, picked unripe, will not spoil because of the
presence of a more-ripe piece of fruit releasing ethylene. In addition, it is easier
to sell similar-sized produce, so grading helps the process of selecting produce of
similar sizes to package together.
Opportunities for careers and entrepreneurship
There are a number of opportunities for careers specifically in harvest and postharvest management and technological developments.
Here are some examples:
• Consumer safety inspectors: These inspectors ensure that products are
produced according to the management plans for Hazard Analysis Critical
Control Points (HACCP), sanitation and processing.
• Food inspectors – export: These inspectors are stationed at ports and make
sure that products for export are packaged and stored appropriately.
• Refrigeration engineers: Refrigeration engineers design, install, repair and
maintain refrigeration equipment in industrial and commercial buildings
where food and other perishable goods are stored at a constant low
temperature.
Entrepreneurial opportunities
Fruit and vegetables have the highest wastage amounts of any food products
with nearly half of all fresh produce ending up as post-harvest losses. Increases
in speed will improve efficiency from the farm to the consumer, especially with
regard to packhouse and repack sorting. Research can analyse data collected by
multiple sensors on the internal attributes of each fruit. With this technology,
300 photographs are taken of each fruit, which means that data of up to 30 MB
is recorded per fruit. With more sorting and grading data available, growers can
apply even more precision agriculture in producing their fruit. Provenance and
traceability will be much better. Packhouse operations can be more productive
and maintenance more predictable. Distribution will be more efficient, providing
the right transport at the right time and retail’s last fulfilment will be aligned to
the product.
Waste from post-harvest losses may retain high value aspects as it can be used as
raw materials in alternative products. These can generate further income for the
farmer. For example, although most of the citrus by-products are used for animal
feed, there are many useful by-products made from different portions of the
citrus fruits, such as pectin, dried pulp, molasses, marmalades, candied peel, peel
seasoning, purees, beverage bases, citrus alcohol, bland syrup, citric acid, seed oil,
flavonoids peel oil, oil and water-phase essences, pulp sacs, and Limonene.
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24: Harvesting, post-harvesting management and value addition
Revision map
Physical
measurements
Physiological
measurements
Chemical
measurements
Maturity indices
are measurements
used to determine
whether produce
can be harvested
The time of
day and appropriate
handling techniques are
vital to secure a
quality crop
Accurate
maturity indices are
used to ensure high
quality at all levels along
the value chain, from
harvest to
consumer
Harvest aids
used mainly by
cooperatives; this
can speed up harvesting
process and reduces
damage
Harvesting
procedures
Harvesting
Maturity
is the basis for
determining exact
stage to pick
a crop
Produce must
be packed properly
into appropriate
containers for
transport from
the field
Cleaning
Sorting
Cooling
Consumer
safety
inspectors
Export food
inspectors
Careers
Relate to
harvest and
post-harvest
management
Refrigeration
engineers
Procedures
developed to
manage the produce
immediately after
harvest
Post-harvest
management
system
Entrepreneurial
opportunities available
in developing harvest
‘waste’ products into
value-added
products
Adding value
to the produce
Slow down
deterioration
Helps
prevent losses
from overripe
produce
Environmental
management
Generates
a different
product
Slow loss of
water from
produce
Aims of
procedures
Maintain
quality and
extend
shelf-life
Increases
likelihood that
produce will be
sold
Packaging
protects the produce
from damage, insect
invasion or
deterioration
Product
transformation
Retains
quality over
long
periods
Packing
Harvesting,
post-harvesting
management and
value addition
Keep out
heat
Produce
containers must have
good stacking strength
in a low-temperature,
high-humidity
environment
Maintain
favourable mix of
oxygen and carbon
dioxide
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Section E: Farm management technologies
Examination-style questions
Multiple-choice questions
Write down the number of the question followed by the letter of the correct answer.
1.
2.
3.
Which of the following is an observation relating to maturity?
A Plant species
B Soil depth
C Fruit texture
D Number of fruit on a plant
Mechanical harvesting is usually used to harvest:
A corn (maize)
B radishes
C citrus
D melons.
The physiological maturity is followed by:
A cell division
B rapid stem growth
C rapid fruit growth
D senescence.
Short-answer and essay-type questions
4.
5.
6.
(a)State THREE observations or measures that can be used to determine a date for
harvest.
(b) Explain how TWO of the observations or measures are carried out by a farmer.
(c) Using an example, explain how the distance the harvested crop has to travel to
market may affect the maturity of the crop at harvest.
(a) List THREE procedures in a post-harvest management system.
(b) Describe ONE procedure in detail and explain why it is important in post-harvest
management.
Complete the table explaining the appropriate post-harvest procedure for each crop.
Name of crop
Tomato
Cassava
Apple
Mango
Cabbage
7.
8.
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Post-harvest procedure
Explain how carefully removing the crop and using appropriate handling maintains product
quality and reduces crop losses.
A farmer notices that his post-harvest produce is getting damaged and he is having to
throw away fruit.
(a) Describe how the produce may be getting damaged.
(b) Suggest ways that the farmer can change his post-harvest handling procedures to
reduce his losses from damaged produce.
Section E: Farm management technologies
25
Post-production
handling and
processing of
livestock
By the end of this unit you should be able to:
✔
✔
✔
✔
Concept map
Processes to prevent
food spoilage
Cooling
Freezing
Drying
Pasteurisation
UHT
Curing
Smoking
describe the processes used to prevent food spoilage
identify principal cuts of meat
describe the food safety requirements for the processing of food
describe the use of animal by-products and animal waste in value
added products.
Post-production handling and processing of livestock
Principal cuts
of meat
Quality requirements
Beef
Lamb
Pork
Poultry
Safety requirements
Animal by-products
and waste
Food preparation areas
Abattoir
HACCP
GMPs
Better marketing
Role of cooperatives
Uses of by-products
Animal waste
Poultry manure
Biogas
Biofuels
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25.1 Processes used to prevent food spoilage
ITQ 1
Describe the causes of food spoilage.
Fresh food can be spoilt by micro-organisms, by enzyme activity in the tissues of
the food and by oxidation. Micro-organisms make food decay. The oxidation of
fats makes foods, such as butter, taste rancid. This spoilage can be delayed for a
short time by using preservation techniques. Some techniques can preserve food
for months and even years.
Cooling
cooling ▶
Cooling keeps food at a low temperature. This process is useful for the short-term
preservation of animal products. Domestic refrigerators are usually kept between
1 °C and 4 °C. Most disease-causing (pathogenic) bacteria require temperatures
above 4 °C to multiply, so keeping meat and milk in a refrigerator for a short
period can prevent spoilage. Cooling also slows down enzyme activity.
freezing ▶
Freezing involves keeping food at temperatures below 0 °C. Meat and fish can
be frozen and stored at –18 °C to –20 °C. Freezing slows down enzyme action and
the growth of bacteria, but the formation of ice crystals in tissues can alter the
texture of the product.
ITQ 2
State the temperature at which fresh
food should be stored in the home
and explain why storage at this
temperature is best.
ITQ 3
Explain how drying food prevents
food spoilage.
drying ▶
Micro-organisms are not killed by cooling or freezing, so microbial activity will
continue when the food reaches a suitable temperature.
Drying
Foods have been preserved by drying for centuries and this method can be used
successfully for meat and fish. When the water content falls below a certain
level, the growth of micro-organisms will stop. In parts of the world where the
atmosphere is dry and the sun is hot, fish and meat can be hung on racks in
the air. Where this is not possible, drying is achieved by forcing hot air over the
products. When food is rehydrated, water is absorbed back into the food, but the
texture and taste will be different. The micro-organisms are not killed by drying,
so spoilage occurs when the water content of the food reaches a certain level.
Pasteurisation
Figure 25.1 Drying is also used for
preserving fruits and vegetables.
The pasteurisation of milk is described in Unit 15. Pasteurisation also preserves
fruit juices, wine, eggs and cream for a short period. The process kills pathogenic
bacteria and reduces the number of other bacteria that could cause spoilage,
but it does not kill spores. Most pasteurisation is carried out by heating to
72 °C for 15 seconds. During the process, milk is passed through pipes that are
surrounded by water kept at just above 72 °C. This heats the milk, which is kept
at this temperature for the correct amount of time and then cooled rapidly to
3 °C. Pasteurised milk and pasteurised juices should be kept refrigerated between
1 °C and 4 °C. The benefits of pasteurisation are that the nutritional content and
flavour are not altered by being exposed to these temperatures.
Ultra high temperature (UHT)
UHT treatment ▶
350
UHT treatment exposes milk and juices to 132 °C for a few seconds to sterilise the
products. The milk is packaged into cartons, which are then sealed under aseptic
conditions. Aseptic conditions are conditions that are free from contamination
from bacteria. The treatment ensures the product now has a storage life of several
months. The vitamin and mineral content is not changed significantly.
25: Post-production handling and processing of livestock
Curing
curing ▶
Figure 25.2 Cured meat.
Curing involves the preservation of meat and fish by the addition of salt, sugar,
nitrates and nitrites.
• Salt removes water from the food and from any micro-organisms, such as
bacteria and fungi. This slows down their growth. A salt concentration of 20%
is needed to kill most pathogenic bacteria. Salting has traditionally been used
to preserve fish (salt cod) and meat (prosciutto ham).
• Sugar is added during some curing processes to give a pleasant taste. It can
encourage the Lactobacillus bacteria, which ferment the sugar, producing lactic
acid. The lactic acid stops the growth of other bacteria and gives the food a
tangy flavour.
• Nitrates and nitrites are used in the preservation of meat and meat products.
Bacon is sometimes cured in this way. Bacteria are killed and the meat retains
a pink colour and its characteristic flavour. The use of these compounds is
controversial as they can produce toxic compounds, called nitrosamines, if the
bacon is cooked at a high temperature. They are effective at killing bacterial
spores, especially those of Clostridium botulinum, which causes botulism.
Treatment with nitrites kills bacteria during the curing process. All smoked
sausages are cured with nitrites before they are smoked.
Smoking
smoking ▶
ITQ 4
Explain how curing food prevents
bacterial growth.
Practical activities:
1. Visit a milk processing facility
in your local area.
2. Watch video presentations
of processes used to prevent
food spoilage.
3. Watch a demonstration of
the preservation of meat by
smoking.
Smoking is the preservation of food by exposing it to wood smoke. It is commonly
used for fish, meat and meat products, such as salmon, ham, bacon and sausages.
Traditionally, it was a way in which food was dried, often having been salted
first. Now smoking is used mostly to add flavour to the outside of the food. Wood
smoke has a low pH and destroys bacteria. It may also contain other compounds,
called antioxidants, which prevent fats from becoming rancid. This is important
in the smoking of oily fish.
Smoking is carried out in a smoker, which consists of a fire box and a food box.
The smoke is produced by a fire in the fire box and it passes into the food box,
which sits on top. Commercial smoke houses are bigger, usually made of stainless
steel and food is arranged on racks that can be moved around. Some smokers use
propane burners to heat the fuel, wood or charcoal. Smoke then passes up into
the section containing the food.
‘Hot smoking’ is carried out by exposing food to temperatures between 74 °C and
85 °C in the smoker. The food is fully cooked, has a good flavour and retains some
moisture. If the temperature gets higher, the food dries out and becomes stringy.
Hams and hocks are hot smoked.
In ‘cold smoking’, smaller pieces of food, such as steaks and chicken breasts, are
smoked for a shorter time at temperatures not above 38 °C. The smoking just
gives some flavour and the food needs further cooking.
25.2 Principal cuts of meat
The principal cuts of meat are described and illustrated in Unit 15.
Quality requirements of meat
The livestock producer aims to rear animals that provide meat that is acceptable to
the consumer. The demand for meat is high as it is an important source of protein.
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Section E: Farm management technologies
Consumers are prepared to pay a good price for meat that has the following
characteristics.
• It is fresh from the farm.
• It contains little fat. There is now more emphasis on the production of lean
cuts as these cuts are considered to be healthier for people. Some fatty tissue is
needed for flavour and for the satisfactory cooking of some cuts.
• It is organically produced. Meat can be called organic only if the animals have
been reared without the use of chemicals or growth stimulants and the crop
or silage used to feed the animals also has not been subjected to chemical
treatment.
Beef
quality ▶
yield ▶
quality grades ▶
Practical activities:
1. Visit a local store or
supermarket and observe the
butchering of carcasses and
the presentation of different
cuts of meat.
2. Process the carcass of one of
the birds you have reared, or
select a method of preservation
for one of the birds you have
reared. Write a report on the
steps taken to process or
preserve the bird.
Meat carcasses are inspected after slaughter and graded according to their quality.
Whole beef carcasses are graded for quality (tenderness, juiciness and flavour)
and for yield (amount of usable meat from the carcass).
There five quality grades.
• Prime grade: This grade is produced from young, well-fed beef cattle. The
meat is marbled (has some fat in and around the muscle tissue). Examples are
prime roasts and steaks.
• Choice grade: This grade is high quality but with less marbling than prime
grade. The roasts and steaks will be tender but other cuts are better cooked by
braising.
• Select grade: This grade is uniform in quality and leaner than the higher
grades. There is less marbling so there is less flavour than in the higher grades.
• Standard and commercial grade: This is ungraded or ‘store brand’ meat.
• Utility, cutter and canner grade: This grade is used to make ground beef and
other meat products.
Yield is graded on a scale from 1 to 5. Grade 1 is the highest grade and means that
the meat has the highest ratio of lean meat to fat.
Beef carcasses are often hung for up to 21 days in a refrigerator to increase their
tenderness.
Figure 25.3 Beef carcass that has been
hung for 21 days.
Figure 25.4 Hanging cut of beef.
Lamb
Usually only two grades of lamb, prime and choice, are retailed. The best lamb
comes from sheep that are about one year old. Meat from older animals is graded
as good, utility or cull. Animals are butchered sequentially to reduce waste. The
series of photographs in Figure 25.5 shows the order of butchery for a lamb carcass.
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25: Post-production handling and processing of livestock
(a)
(b)
Loin
(d)
(c)
Ribs
(e)
Lamb breasts
Frenched ribs
(f)
Legs
Shanks
Figure 25.5 Lamb butchery shown in order of butchery.
Pork
Pork is produced from young pigs bred to produce uniform meat, so it is not often
graded in the same way as beef or lamb.
Pork meat should have:
• a firm texture
• a greyish-pink colour
• a small amount of fat over the outside
• fat that is firm and white.
Figure 25.6 Pork carcass prior to
preparation. Notice the thick skin and fat
layer still to be removed.
Abattoir, Jamaica
Farmer Cohen rears livestock, small ruminants (sheep and goats) and fish. She operates
an abattoir on the farm and employs graduates from Ebony Park to carry out the slaughtering,
dressing and packaging of meat. One of the employees prepared the fish and mutton using the same
cutting board and knife without sanitising between uses. The packaged meats were delivered to the local
supermarket in an open-bed pick-up truck. Several unsuspecting consumers soon displayed symptoms of food
poisoning. An investigation by the Health Department resulted in the owner of the abattoir being summoned
to court and fined. All packages of meat were recalled and removed from the shelves of the local supermarket. For
several months afterwards, there was a lack of confidence in Farmer Cohen’s brand and products.
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Section E: Farm management technologies
ITQ 5
Poultry
Describe the properties of goodquality pork.
There are three grades for poultry: A, B and C. Grade A is the highest quality
and is usually the only one sold in supermarkets. There should be no bruises or
discolorations. There should be no feathers left in, broken skin, or broken bones
in joints. The flesh should be meaty with a layer of fat under the skin. The other
grades are used for processed products.
Practical activities:
1. Visit your local store and
assess the quality of different
cuts of meat and poultry
offered for sale.
2. Describe which cuts cost the
most money and give reasons
for why this is.
25.3 Safety requirements for food processing
Food processing involves the handling, preparation and storage of food products.
Food-processing industries include canning, meat slaughtering and meat
processing. In all these industries, strict regulations prevent the contamination of
the food by micro-organisms that could cause disease.
Food preparation areas
In general, all food preparation areas and equipment are cleaned and sterilised
on a regular basis. This involves using chlorine bleach or ethanol or sterilisation
by ultraviolet (UV) light. People who work in food-processing industries wear
protective clothing, such as overalls, gloves and boots, and cover their hair with
hats or hairnets.
Places in which food is prepared or processed should:
• be well ventilated to prevent condensation falling on to food or surfaces
• have washable walls, floors and ceilings for easy and regular cleaning
• have food preparation surfaces, tools and equipment that are resistant to
corrosion and made of non-toxic materials
• be screened to exclude birds, flies and other pests that could introduce
bacteria and contaminate food
• have toilet facilities and a separate hand-washing basin so that hand-washing
does not take place in the same basins as those used to clean equipment.
Figure 25.7 Food processing students in a
food-processing plant, holding food products
that they have processed.
sanitary measures ▶
ITQ 6
Name FOUR items of protective
clothing used by workers in the
food-processing industry.
If meat and meat products are being processed, it is usual for a food inspector to
be present.
Abattoir
In abattoirs (slaughterhouses), strict hygiene is maintained. All carcasses are
inspected and stamped as either fit for human consumption or unfit, in which case
they are burned or buried. By observing sanitary measures (hygiene measures),
consumers are protected from meat-borne diseases.
Abattoirs should have the following features.
• They should be well ventilated and fly proof.
• They should have a non-slippery, tiled or concrete floor that is slightly sloping
for easy cleaning.
• They should have a chiller or cooling room for meat carcass storage.
• They should have a drainage system to collect solid and liquid waste.
After the animals have been slaughtered, the abattoir and all equipment is cleaned
and washed thoroughly.
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25: Post-production handling and processing of livestock
The procedures described in this section are used internationally to ensure that
food is produced and processed in a safe way. Good agricultural practices (GAPs)
are applied to crop production and animal husbandry, whereas HACCP and
GMPs, which are discussed in the following sections, relate to the manufacture
and processing of food.
Hazard Analysis Critical Control Point (HACCP)
Hazard Analysis Critical ▶
Control Point (HACCP)
hazard analysis ▶
Hazard Analysis Critical Control Point (HACCP) is a systematic approach
to food safety used to identify potential hazards in the food industry. It is used
at all stages of food production and preparation, particularly the production of
juice, seafood, meat and poultry products. It ensures that food is fit for human
consumption by monitoring the stages in its production.
There are seven HACCP activities.
1. Conduct a hazard analysis to identify measures that can be taken to control
any biological, chemical or physical hazard that could cause food to be unsafe
for human consumption.
2. Identify critical control points (CCPs) in a food manufacturing process at
which a hazard can be prevented, removed or reduced.
3. Establish critical limits for each CCP. A critical limit sets a value at which a
hazard must be controlled at each point.
4. Establish CCP monitoring requirements to ensure that the manufacturing
process is under control.
5. Establish corrective actions to be taken when the monitoring process indicates
that a critical limit is not being met. This ensures that products harmful to
health do not become available for human consumption.
6. Establish record-keeping procedures so that it is evident that all steps of the
process have been monitored for hazards.
7. Establish procedures for ensuring that the HACCP system is working as it
should be and that the products from any manufacturing process are safe.
Food-processing plants must produce products that are safe. The plants are
required to validate their own HACCP plans, which have to be verified to make
sure that they are adequate. Verification includes reviewing plans, inspecting
critical control point records and microbial sampling.
Good manufacturing practices (GMPs)
good manufacturing practices (GMPs) ▶
Good manufacturing practices (GMPs) regulate the manufacture and testing
of food products, drugs and medicines. Every aspect of a process is documented
so that products can be traced and recalled if they are unsatisfactory. GMPs are
particularly important in the manufacture of pharmaceutical products (medicines).
GMPs in the food industry identify and prevent the contamination of raw materials.
They also deal with poor design of processing plants and the procedures and
deficiencies in training employees. Refrigerated foods, meat and dairy products
have a high risk of safety problems as they may become contaminated with
pathogens. Another problem is that allergens may be introduced into foods (some
people, for example, are allergic to nuts). Food safety experts recommend that
employee training is important to maintain quality control of materials, adequate
cleaning of equipment and documentation of procedures. GMPs, together with
HACCP, ensure that manufactured food products are fit for human consumption.
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25.4 The use of animal by-products and waste
in value-added products
Farmers and producers are continually looking for ways in which they can make
more profit. There is therefore interest in using the by-products and wastes from
livestock rearing to increase farm income.
There are three ways in which the farmer can add value to animal produce.
• Market animal products better.
• Make use of by-products.
• Make use of animal wastes.
Better marketing of animal products
ITQ 7
Explain FOUR ways that farmers can
improve their marketing of animal
products.
ITQ 8
Explain how cooperatives can reduce
the costs of farm production.
Farmers can make a greater profit from their produce in the following ways.
• They can sell direct to consumers in farmers’ markets, local stores and
supermarkets rather than selling more cheaply to a wholesaler.
• They can sell prime and choice cuts of their meat directly to hotels and
restaurants.
• They can rear and market a particular breed of animal known for its flavour
or succulence.
• They can market their produce as coming from a particular region.
• They can obtain organic certification and market their meat, eggs and milk as
organic.
• They can produce and market their own processed foods, such as yoghurt,
ice cream and cheese.
• They can develop a brand name and market their labelled produce.
There is also profit to be made from the sale of:
• laying hens that are past their productive peak
• semen from pedigree males, such as bulls and boars, which can be used
for breeding
• hive products such as royal jelly, wax and propolis.
The role of cooperatives
The costs of rearing livestock, and providing housing, feed and medication, are
paid by the individual farmer; but costs of slaughtering, processing plants and
transport can be reduced if farmers form local cooperatives, where facilities are
shared. See Unit 17 for more about cooperatives.
Making use of animal by-products
Some by-products of livestock production can be used profitably.
• Offal: Organs such as kidney, liver, brain and heart can be used for human
food or pet food.
• Hides: Skins of slaughtered animals can be used for leather products such as
handbags, belts and shoes.
• Feathers and hair: Feathers can be used in pillows and cushions and for
insulation, and hair can be used as stuffing.
• Bones and blood: Bones and blood can be converted into bonemeal and blood
meal and used in animal feed and as fertiliser.
• Fat: Fat can be rendered down (melted) from carcasses and used to make lard
for cooking and soaps.
• Hooves and horns: Hooves and horns can be ground up and used as fertiliser.
• Meat scraps: Meat scraps can be used to make pet food.
All these by-products can be separated from the bodies of the animals and sold to
specialist producers.
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25: Post-production handling and processing of livestock
Animal wastes
It was previously good practice to burn or bury carcasses and wash away blood
from abattoirs. But there are now concerns about the effect on the environment,
so farmers are encouraged to convert waste products into animal feeds or biofuels.
This makes sense, particularly as there is profit to be made by the farmers.
It is profitable to compost animal dung and litter to make manure that can be
spread on ploughed land. The farmer saves money on fertilisers and the system
works well on mixed and small farms. However, the waste produced by larger
farms that specialise in broilers or layers or the intensive rearing of cattle is large
in quantity and difficult to remove.
Animal waste is often used as animal feed.
• Broiler litter is converted into feed for beef and dairy cattle.
• Poultry waste and waste from the sweet potato industry are converted into
feed for poultry.
• Eggshells, which are a hatchery by-product, are crushed and used to add
calcium to animal feed.
• Feathers are processed into feed. Bacteria break down the protein in the
feathers. The protein is then incorporated into the animal feed.
• Carcasses of large animals are rendered down and different parts are used to
make animal feed.
The conversion of animal waste into animal feed is carried out in processing
plants, which are often owned and run by local cooperatives. The wastes are
milled (ground up), mixed with other feed components and formed into pellets.
poultry manure ▶
ITQ 9
Describe how the waste product
of eggshells from hatcheries can
be used.
ITQ 10
Explain how animal wastes are
converted into animal feeds.
Poultry manure is removed from a poultry pen after a batch of broilers or layers
has been reared. It is packed into feed bags, loaded on to a trailer and transported
to a cropping area where it is composted. It is usually stored in an enclosed area
and used as required.
Rotted poultry manure is a fertiliser for the cultivation of vegetable crops such as
ochro, pumpkin, tomato, cabbage and bodi beans. Bagasse-based poultry litter is
an ingredient in the feed of small ruminants, such as sheep and goats.
Biogas
The use of manure to produce biogas is described in Unit 15. The economic
advantage of this is that fuel costs are reduced. Biogas is used widely throughout
the world, especially in isolated areas where individual farmers have biogas
generators. In the Caribbean, the production of biofuels from plant waste is
already well established.
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Section E: Farm management technologies
Revision map
In warm
countries food can be
dried outside,
otherwise this is done
by forcing hot air
over food
Reduces water
content and stops
the grown of
micro-organisms
Milk and
other foods can be
pasteurised – pathogenic
bacteria are destroyed but
the flavour and qualities of
the product are not
significantly
altered
Drying
food
Low
temperatures
inhibit bacterial growth
so keeping fresh food
cool can delay
spoilage
Canner
(used in meat
processing)
UHT
(Ultra Heat Treatment),
in which foods are subjected
to a high temperature for a few
seconds, enables foods to be
stored without
refrigeration for
several months
Utility
Cutter
Quality
grading evaluates
tenderness, juiciness
and flavour of
the meat
Curing preserves
meat and fish using
salt, sugar, nitrates
and nitrites
Smoking
preserves by smoking,
which is a form of
dehydration that
adds flavour
Preventing
food spoilage
Prime
(the best)
Carcasses
are inspected
and graded according
to their quality
and yield
Grades
Pork is
not graded in this
way; appearance and
texture of the meat
is described
instead
Grades and
cuts of meat
Oxidation
Causes
of food
spoilage
Post-production
handling and
processing of
livestock
Enzyme
action
Micro-organisms
Hides
Profit
possible from
selling by-products
of animal
production
Hooves
Horns
Food
processing
Using animal
by-products
and waste
products
Uses of
animal
wastes
Employees
should wear
protective
clothing
Farmers could
gain more money by
changing methods
of marketing their
produce
Generating
biogas
Bones
Feed for
livestock
(e.g. poultry
litter)
358
Food handling
areas and equipment
must be cleaned
and sanitised
regularly
Fertiliser
HACCP
guidelines used for
the safe production
of processed
food
Premises should
be well-ventilated,
have washable walls and
floors and be screened
to prevent entry of
birds and other
animals
25: Post-production handling and processing of livestock
Examination-style questions
Multiple-choice questions
Write down the number of the question followed by the letter of the correct answer.
1.
2.
3.
4.
Food spoilage can be avoided by:
A cooling food to 10 °C
B curing meat with salt
C boiling food to 100 °C
D curing meat with carbon.
State TWO products of prime grade beef.
A Wing and breast
B Back bacon and breast
C Prime roast and steak
D Leg and breast
Food preparation areas should:
A be well ventilated and have carpets
B have toilets and patterned wallpaper
C have washable walls and be well ventilated
D have carpets and wallpaper.
The following by-products can be used for pet food:
A Offal and feathers
B Offal and fat
C Hides and meat scraps
D Offal and meat scraps
Short-answer and essay-type questions
5.
(a) Describe the by-products from sheep and goat farming.
(b) Explain how better marketing of these by-products can increase a farm’s profits.
6. Lamb carcasses are butchered in a specific sequence. State the products produced in order.
7. (a) Explain why food spoilage occurs.
(b) Describe THREE ways in which food spoilage can be prevented.
8. (a) Describe how fresh milk can be treated to prevent spoilage.
(b) How might a farmer process surplus milk on the farm?
9. (a) Explain how a farmer can increase the profits from animal production.
(b) Suggest how animal wastes can be used.
10. Explain how HACCP can improve food safety.
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Section E: Farm management technologies
26
Agroengineering
By the end of this unit you should be able to:
✔ design simple farm structures
✔ recommend suitable materials for use in farm buildings
✔ demonstrate the safety precautions in the operation of tools, machinery
and equipment
✔ describe the use and operation of mechanical systems in farm equipment
✔ demonstrate the appropriate care and maintenance of simple tools and
equipment.
Concept map
Agro-engineering
Design simple
farm structures
Plant nursery
Greenhouse
Post-production
facilities
Machinery shed
Compost shed
Workers’ facilities
Suitable materials
Local
Imported
Properties
Foundations
Floors
Walls
Roofs
360
Safety precautions
Health and safety at work
Certification
Checklist for
Tools
Machinery
Equipment
Personal protective
equipment (PPE)
Safety devices
Safety practices
Tractors
Fuels
Chemicals
Safe disposal
Agricultural chemicals
Dilute pesticide solution
Use and operation of
mechanical systems
Safe hitching
Drawbar hitch
3-point linkage
Tractor attachments
PTO shaft
Ploughs
Rotovator
Harrow
Brushcutter
Trailer
Fertiliser spreader
Manure spreader
Crop sprayer
Care and maintenance
of simple tools
Plant nursery
Cleaning
Drying
Sharpening
Repairing
Painting
Oiling / Greasing
Storing
Keeping records
Knapsack sprayer
or mistblower
Simple tools
Weed trimmer
Irrigation pump
Defeathering machine
Debeakers
Clippers
Milking machine
26: Agro-engineering
26.1 Designing farm structures
Farm structures need to be well built and safe, like any building. Farm buildings
need to be planned before being built, even if part of the structure will be added
at a later date, when funds are available. Retrofitting buildings is the process of
making changes to a building that already exists to add new features. This process
is more difficult, time-consuming and costly than building a new structure. Larger
buildings obviously cost more to build than smaller ones, but if your first building
is too small, it will cost more to build two small ones than to build one larger
building.
Plant nursery and greenhouses
Figure 26.1 Plant nursery and
greenhouse.
ITQ 1
Explain why it is important for
greenhouses to have plumbing fitted.
Planning a plant nursery requires thinking about the size, whether electricity is
required, and how the nursery will be provided with water (plumbed) to irrigate
the plants. Some farmers prefer to locate their plant nursery in different areas of
the farm during the dry and rainy seasons. This means that the structure will need
to be more temporary so that it can be deconstructed and relocated. A permanent
structure may have a concrete base, which will be easier to clean down, but this
will be more expensive to build.
Greenhouses are most commonly made from clear composite plastics over a metal
or wooden frame. The plastic may be sheeting, although this can tear easily, so
PVC plastic is better on a fixed structure. Within a nursery, the seedlings need to
be on tables that are the right height for the farmer so that he or she does not
get backache. It is also a good idea to have space to store soil and compost for the
seedling trays.
Post-production facilities
Practical activities:
1. Visit farms to understand the
purpose behind farm structure
designs and the position of
farm buildings.
2. Make models of farm
structures.
After plants have been produced, fruit and vegetables need to be harvested and
stored safely before being transported to market. After the produce has been
harvested, it is easily spoilt by bruising, insects or mould. The farmer has a limited
time to get the produce to market or process it in some way that will extend
its shelf-life. Post-production facilities depend on the scale of the farm, type of
produce and distance to market.
Machinery shed
Machinery sheds need to have a solid base to prevent oil or other chemicals
entering the environment. They should have a roof and walls to protect the
machinery from rain as metal will rust.
Compost shed
Compost needs to be kept under cover, or rainfall will make it too wet and will
cool the organic matter, preventing bacteria from breaking down the compost.
ITQ 2
Explain the design of a machinery
shed.
Workers’ facilities
Farm workers need to have a place to shelter from the weather. It should be
cool in the dry season and roofed for the wet season. There should be a place for
workers to keep their protective equipment, and there should be a restroom and
sink for workers to wash their hands before eating.
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Section E: Farm management technologies
26.2 Suitable materials for farm buildings
Refer to Section 23.2 in Unit 23 to revise materials that are suitable for constructing
farm buildings.
roofing
sheets
concrete
blocks
concrete
foundations
concrete
floors
Figure 26.2 Animal house building.
ITQ 3
State TWO advantages of using
galvanised iron / steel sheets for
roofing.
Practical activity:
Label the models that you made of
farm structures, with the building
material and any important
features.
ITQ 4
Explain why agriculture is considered
a high-risk occupation.
26.3 Safety precautions in the operation of
tools, machinery and equipment
Occupational health and safety in the workplace
Health and safety requirements at work have a major impact on working people,
their working environments and the way the people work. In workplaces around
the world, work-related deaths, injuries and illnesses still occur every day.
Agriculture is a high-risk occupation. Risks include being crushed by livestock,
inhaling poisonous chemicals, being injured by machinery and straining muscles
lifting heavy bags of produce. Occupational health and safety (OHS) is increasingly
considered as a part of public health in the Caribbean. Throughout the Caribbean,
the International Labour Organization (ILO) has provided technical assistance
in the development of a CARICOM Model Law on Occupational Safety and
Health and the Working Environment. The model law has influenced the new
occupational safety and health (OSH) legislation in countries such as the Bahamas,
Guyana, Suriname and Trinidad and Tobago.
Certification
Caribbean safety standards should be in place for agricultural enterprises that
have employees. Certificate-holding companies have been approved that they are
able to work in a safe and responsible manner in their specific sector. Companies
seeking accreditation should apply to the Caribbean Health and Safety Foundation.
Following safety procedures is necessary for the safe operation of all tools,
machinery, equipment, fuels, pesticides and other chemicals.
Have I chosen the best tool / machine / equipment
for the task?
Practical activities:
1. Design posters to show how
tools should be handled safely.
2. In pairs, practise safe handling
of tools, by one student
following the instructions of
the other student. Before you
change over, recap any steps
that were forgotten.
Is the tool / machine / equipment in good condition,
with any handles firmly attached, blades or prongs
clean and sharp and moving parts greased?
Do I need further training on how to control this tool
/ machine / equipment before attempting the task?
Can I complete the task without interruption, or do I
need to place a sign, or turn off my phone before I
start to avoid distractions?
If I do have to stop mid-task, is there a safe place
for me to put down the equipment? Sharp tools
should be stuck upright in the soil, or if horizontal,
with sharp edges or prongs facing downwards,
away from animals, children or substances that
may catch fire.
Have the safety devices been checked recently,
and are they still fully operational? Safety devices
include clips, buttons, bars, shields, guards, filters,
safety fuses, colour-coded lights and automatic
shut-off to stop the equipment if there is a blockage
or malfunction.
Figure 26.3 Safety checklist for tools, machinery and equipment.
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26: Agro-engineering
Safety equipment
Safety equipment protects both the operator and the machinery. It may consist of
special gear for use with equipment or safety devices on the machinery.
safety gear ▶
safety devices ▶
Safety gear is also known as personal protective equipment (PPE) and includes:
• clothing: coveralls that are tough, durable and fireproof
• head gear: hard hat or helmet, often with face shield
• boots: steel-tipped, with non-skid soles
• gloves: leather, fabric or disposable
• safety glasses or goggles
• respirators and face masks: protection from fumes, smoke and dust
• ear-muffs: protection from loud noises.
Machinery and equipment may be fitted with safety devices such as:
• safety clips, buttons, bars
• shields, guards, filters
• safety fuses
• colour-coded lights
• automatic shut-offs that stop the equipment if there is a malfunction.
Safe practices with tractors
Tractors and attachments should be in good condition. Attachments should
be safely hitched with protective shields and safety guards in place. The driver
should be appropriately trained and dressed in hard hat and steel-capped boots
with no dangling clothing, straps or belts. Tractor operators need to be aware of
the location of slippery slopes, gas, electricity and water pipes and cables, children
and animals. The handbrake should be on and the engine off before unhitching
any attachments. SAFE STOP should be practised whenever tractor operations
are interrupted (see Unit 7).
Figure 26.4 Person wearing full PPE.
ITQ 5
State the items of personal protective
equipment (PPE) that should be worn
by someone handling chemicals.
ITQ 6
Explain how to dispose of leftover
pesticides safely.
Safe handling of fuels and chemicals
Most fuels on a farm are flammable and need to be handled carefully. Gasoline,
diesel and kerosene are used to power tractors, water pumps and generators.
Fuels should be stored in special containers that have been approved by the
Bureau of Standards. There should be ‘no smoking’ and ‘no naked flame’ signs in
the chemical storage areas and in areas where the fuels are handled. Storage areas
should remain locked when not in use. Chemicals such as artificial fertilisers and
pesticides should be handled with care and also stored in a locked room. Personal
protective equipment should be worn at all times and all containers need to be
triple rinsed with clean water after use.
Safe use of agricultural chemicals
• Ensure that anyone who uses agricultural chemicals is suitably trained to use
both the chemical and any equipment required for application.
• Follow the manufacturer’s instructions given on the label.
• Use a special chemical decanting kit, or a plastic tray for a knapsack sprayer, to
reduce the risk of spills and splashes while mixing chemicals.
• Only mix the quantity of chemical required for the task at hand.
• Make sure the decanting and mixing area is well ventilated. If this is not
possible, ensure that recommended personal protective equipment is worn for
enclosed environments.
• Always wear appropriate protective clothing such as chemical-resistant gloves,
overalls, goggles and appropriate P2 face masks or a P3 respirator. (Respirator
cartridges should provide multi-level gas protection.)
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Section E: Farm management technologies
• Avoid exposing non-target animals or plants.
• Triple rinse equipment after chemical application and dispose of the rinse
water (rinsate) appropriately. Rinsate contains low concentrations of the
chemical from the cleaning process.
Practical activity:
Visit a farm in your local area to
find out:
(a) where the farmer stores his or
her agricultural chemicals
(b) what he or she wears to stay
safe from the chemicals
(c) where and when the farmer
sprays different chemicals
(d) how the farmer avoids having
leftover pesticides
(e) where the chemicals are
disposed of.
Back at school, use the information
in this unit to make a list of
improvements that the farmer could
do to make spraying chemicals
safer for:
• people
• wildlife
• the environment, especially
rivers.
Disposal of agricultural chemicals
Pesticide waste includes chemicals that have been rinsed from washing the sprayer
tank (rinsate), and contaminated material that has been in contact with pesticides
and pesticide packaging, for example, containers, lids and foil seals underneath
lids. Farmers and growers should dispose of chemicals responsibly and legally to
keep the unwanted effect on people or the environment as low as possible.
When farmers reduce their use of pesticides, they not only save money, they also
reduce the amount of waste pesticide and empty containers they produce.
The answers to the following questions about pesticides provide a useful guide to
using pesticides.
• Is using the pesticide absolutely necessary? If it is needed, can the same effect
be achieved with less product?
• Is the suitable pesticide available on the farm, or must new stock be ordered?
• Is the pack size available the most suitable size?
• Is there a more effective way to manage the pests?
• Is it possible to reduce packaging waste and washing by using:
• soluble packs?
• returnable containers?
• closed-transfer systems?
• flushing systems for low-volume sprayers?
• direct-injection systems?
• rounding down the calculation of the amount of pesticide needed to fill the
sprayer, to allow you to dispose of the washings on an under-dosed area or
using a suitable electronic sprayer controller to achieve the same result?
• Will the contractor or distributor take back properly cleaned empty
containers? (Cleaned using a pressure rinsing device or manually rinsed at
least three times.)
Follow these steps if the rinsed containers need to be stored before they can be
disposed of.
• Firmly replace the cap on the container immediately after rinsing and draining
it into the equipment used for applying the pesticide.
• Put the rinsed foil seal inside the container.
• Store the rinsed and drained container upright in a secure, weatherproof area
away from stored pesticides, either in a separate store or in a separate part of
your chemical store, until it can be disposed of.
Disposing of dilute pesticide solution
Plan your spraying so that you do not have any pesticide left over in the spray
tanks. This will also reduce waste disposal problems and save money. However,
in some situations, such as when you are applying a pesticide as a before-planting
or after-harvesting dipping treatment, you may not be able to avoid having dilute
pesticide left over at the end of the treatment. When treating several sites one after
another, using the same pesticide and the same equipment, use leftover spray
from one site to treat another, if you can transport the pesticide safely. All dilute
pesticide waste, including any leftover pesticides and all sprayer washings, should
be disposed of safely and legally to protect people, wildlife and the environment,
especially the groundwater and surface water.
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26: Agro-engineering
When you have finished applying the pesticide, clean the insides and outsides of
all the equipment you used.
ITQ 7
Describe how to clean a knapsack
sprayer when you have finished
applying a pesticide.
By thoroughly cleaning the application equipment following the manufacturer’s
instructions, there is less chance of:
• risk from handling contaminated surfaces
• damage to other crops and areas that will be treated later using the same
equipment
• blockages in the application equipment. The tank, pipes, hoses, filters, valves,
nozzles and induction systems require thorough cleaning.
26.4 The use and operation of mechanical
systems in farm equipment
transmission system ▶
A transmission system is a system of gears and shafts that transmits engine
power to a vehicle’s wheels. Tractors have transmission systems. This system
results in the forwards and backwards movements of the tractor in different field
conditions.
power train ▶
Power train is the name given to the complete path of power from engine to
wheels.
rear axle
pulley
clutch
power take-off
shaft
three-point
linkage arms
differential
hitch
front axle
power
take-off
gearbox
rear wheels
Figure 26.5 The mechanical system of a tractor.
drawbar
Figure 26.6 The back of a tractor.
Safe hitching of implements
Tractors have been designed to tow or connect to different implements. It is
important that these implements are hitched correctly for the safe and efficient
operation of the tractor. Implements can be towed, semi-mounted or mounted.
There are two types of hitch on a tractor: the drawbar and the three-point linkage.
drawbar hitch ▶
A drawbar hitch is a device by which the pulling power of the tractor is
transmitted to the trailing implements.
three-point linkage ▶
A three-point linkage is a combination of three links, one upper and two lower
links. The links are articulated to the tractor and the implements at their ends in
order to connect the implement to the tractor, but separate should the implement
overturn.
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Section E: Farm management technologies
The three-point linkage has the following advantages:
• easy control of working implements
• quick setting of implements
• automatic hydraulic control of implements, such as position control and draft
control
• good balancing of attached implements.
ITQ 8
Tractor attachments
State TWO ways that attachments
are safely secured to a tractor.
Refer to Section 7.2 in Unit 7 to revise tractor attachments.
Figure 26.7 A disc plough.
Figure 26.8 A chisel plough.
Figure 26.9 A fertiliser spreader.
Figure 26.10 A mouldboard plough.
26.5 Care and maintenance of simple tools and
equipment
Refer to Section 7.4 in Unit 7 to revise the care and maintenance of tools and
equipment.
Simple tools
Each tool or piece of equipment is specially designed for carrying out a particular
agricultural operation. It is therefore important to choose the tool or equipment
best suited to the task: using the wrong tool can be hazardous.
These safety practices should be followed.
• Ensure that the tool or piece of equipment is in good condition, with any
handles firmly attached, blades or prongs clean and sharp, and moving parts
oiled or greased.
• Wear the correct safety gear: tall rubber boots, goggles, gloves, coveralls, hard
hat where appropriate; avoid dangling straps or belts.
• Control the equipment when chopping, digging, cutting, brushcutting or
weeding.
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26: Agro-engineering
• Focus on the task while operating the equipment; stop if you become
distracted.
• Place equipment down safely when not in use; sharp tools should be stuck
upright in the soil so that they are clearly visible, or placed flat on the soil
with their prongs or sharp edges facing downwards.
• Avoid laying tools or equipment on pathways or on heaps of weeds, where
they could cause injury or be forgotten.
Weed trimmers
Figure 26.11 Weed trimmer in use.
Weed trimmers, also known as strimmers (or string trimmers) are excellent for
managing weeds. Before doing any trimmer maintenance, ensure that the power
button is in the off position, the fuel tank is empty and the spark plug wire is
disconnected. A couple of times a year, clean the exterior of the trimmer well using
a mixture of water and dish detergent and a brush to clean off any grease, dirt
or debris. Replace the string whenever necessary. Change the air filter regularly
(according to the instruction manual for the specific device). Every 3–4 months,
depending on use and dirt build-up, change the spark plug and add engine oil to
the cylinder. When you put the weed trimmer away at the end of the season, first
check that the fuel tank is empty and all the nuts and screws are tight.
Irrigation pumps
For irrigation pumps to work consistently, you need to clean off mineralised salts,
including calcium and magnesium, which are common in ‘hard’ water areas.
Maintain pumps to keep them working safely, make them last longer, and remain
as efficient as possible by:
• lubricating electric motor bearings with a hand-operated grease gun only
• at the end of the season, pumping in grease until old grease is expelled from
the relief plug
• at the beginning of season, starting up the motor and letting it run until
surplus grease is expelled
• having a qualified electrician perform electrical maintenance, such as ensuring
all electrical connections are secure and not vandalised, checking motor
full-load amperage and ensuring it is the same as the nameplate on the motor
• preventing pump backspin and hydraulic shock, which can severely damage
the pump and motor, by installing at least one check valve in the discharge pipe
• anchoring, supporting and restraining suction and discharge piping near the
pump to avoid excess application of forces and moments. Pump vibration
dampening will help achieve optimum operation and minimum noise
and vibration
• checking all alarm point settings and control and alarm systems. Install
undercurrent relays in the power supply lines to prevent excessive drawdown.
Figure 26.12 Defeathering machine.
defeathering machine ▶
Defeathering machines
Defeathering machines pluck feathers from poultry much more quickly than
people can. An automated plucking machine uses rubber posts sticking out from
the inside of a spinning / tumbling drum to pull the feathers from the bird. This
process takes less than 30 seconds, whereas manual plucking typically takes
several minutes. A small defeathering machine can process 25 birds per minute.
It can be difficult to clean a defeathering machine as it has small moving parts. In
addition, if the skin on the bird tears, then bacteria can enter the bird easily. This is
why poultry are often plunged into boiling water immediately prior to plucking.
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Section E: Farm management technologies
Debeakers
debeaker ▶
Chicks that will become layers are debeaked to prevent them causing damage to
other members of the flock. Cannibalism occurs among chickens. It is the activity
where members of the flock peck at each other, causing bleeding and loss of
flesh. If the pecking is severe, it may result in death. To prevent this, chicks are
debeaked. In debeaking, a third of the top beak of each bird is removed with a
hot iron (a debeaker). This part is burned off and the beak is cauterised. The tool
needs to be kept clean so that bacterial infections are not caused by the process.
Pecking can also be reduced by hanging bundles of fresh herbage in the pens of
layers.
Clippers
clippers ▶
Clippers need to be cleaned with a brush to reduce a build-up of hair or wool
that will prevent the mechanism from working properly. The blade needs to be
oiled too because the less friction there is, the more easily the clippers will cut.
Check the cable regularly because a damaged cable could lead to electric shock.
Milking machines
milking machine ▶
368
Milking machines vary depending on the size of the herd and the type of animal
that is to be milked. Cows, sheep and goats are all used in the Caribbean to provide
milk. Often, milking machines are not looked after properly. This can have a
serious effect on the spread of mastitis and on the quality of the milk. Milking
machines should be tested every six months by a qualified technician, which will
ensure that teats are not damaged or cross contaminated with mastitis. A hot
wash after every milking will ensure that mastitis-causing bacteria are destroyed.
Old liners can harbour and aid the transfer of bacteria, cause teat damage and
leave cows open to mastitis infection. Rubber liners should be changed every
2 500 milkings or six months, whichever comes first. Silicone liners have a much
longer life of up to 10 000 milkings. Teats should be inspected for black spots
(bruising) or other damage, as this is likely to be a sign of poor pulsation / vacuum
in the milking machine.
26: Agro-engineering
Revision map
Aggregates
Machinery
shed
Distance
to market
Compost
shed
Metals
PVC
Lumber
Clay
Workers’
facilities
Local
materials for farm
buildings and animal
housing
Examples
of post-production
facilities
Type of
produce
Scale of
the farm
Suitable
materials for
buildings
Design
of farm
structures
Workers
should be trained
on how to use the tools
correctly and follow
safety procedure
Personal
protective equipment
used to protect
workers
Safety devices
on machinery and
equipment protect
workers using the
equipment
Simple tools
Records
should be kept of
their servicing and
any replacement
parts
Ceramic
products
Safety
precautions
Agro-engineering
Tools
should be used
and maintained
properly
Metals
Imported
materials for farm
buildings and animal
housing
Post-production
facilities
depend on
Farm
structures need
to be planned,
well-built and
safe
Lumber
Concrete
Using
mechanical
equipment
Chemicals
and the
environment
Tractors
have different
attachments to do
different tasks
Equipment
should be in good
condition
Workers
should be trained on
how to use equipment
correctly
Chemicals
must be disposed of
correctly to protect
people and the
environment
Chemicals
should be stored
safely
Reducing
the use of pesticides,
reduces the amount of
waste pesticide and
empty pesticide
containers
369
Section E: Farm management technologies
Examination-style questions
Multiple-choice questions
Write down the number of the question followed by the letter of the correct answer.
1.
2.
3.
4.
The best attachment to use to break up a hardpan is a:
A mouldboard plough
B disc plough
C chisel plough
D rotovator.
A face mask should be worn when operating a:
A crop sprayer
B manure spreader
C fertiliser spreader
D harrow.
Which agricultural equipment would you use to clear shrubs and vines from an area of abandoned land?
A Rotovator
B Brushcutter
C Harrow
D Plough
Which of the following is NOT a stage in caring for simple tools and equipment?
A Cleaning
B Oiling or greasing
C Repairing
D Watering
Short-answer and essay-style questions
5.
6.
7.
8.
9.
370
(a) Giving examples, distinguish between tractor attachments used for: (i) primary tillage, and (ii) secondary tillage.
(b) State the main purpose of each of the following attachments.
(i) Brushcutter
(ii) Rotovator
(iii) Harrow
(iv) Trailer
(a) List safety gear for workers handling agricultural machinery.
(b) Name FOUR types of safety devices usually built into agricultural machinery and equipment.
(c) State the importance of safety equipment.
(a) Name hand tools and equipment best suited for the following agricultural operations.
(i) Tillage
(ii) Drainage
(iii) Harvesting
(b) State the safety practices that should be followed when using agricultural tools and equipment.
(c) List the practices necessary for the maintenance of agricultural tools and equipment.
(a) Name THREE combustible fuels commonly used on the farm.
(b) State the importance of such fuels for the farmer.
(c) Explain the precautionary measures that should be followed in handling such fuels on the farm.
Describe how you would use a knapsack sprayer to apply pesticide to a crop. Include safety measures and how you
would clean the equipment after use.
Section F: Entrepreneurship and communication
27
Entrepreneurship
in agriculture
By the end of this unit you should be able to:
discuss the concept of entrepreneurship
discuss the forms of business organisations and arrangements
explain the steps in establishing an agricultural enterprise
discuss the importance of strengths, weaknesses, opportunities and threats
(SWOT) analysis in decision-making for agricultural enterprises
✔ identify the factors that contribute to the success and failure of entrepreneurs
in agricultural enterprises
✔ explain the purpose of key financial statements in decision-making.
✔
✔
✔
✔
Concept map
Entrepreneurship
Types
Opportunity based
Necessity based
Reasons for becoming
an entrepreneur
Personality
traits
Entrepreneurship in agriculture
Business
organisations
Sole trader
Partnerships
Cooperatives
Limited companies
Franchises
State-owned
corporations
Non-governmental
organisations
Establishing an
agricultural enterprise
Identifying opportunities
Feasibility analysis
Development of a
business plan
Resources
Management operations
SWOT
Factors influencing
business
Success
Failure
Key financial
statements
Profit and loss
Balance sheet
Cash flow
Purpose
371
Section F: Entrepreneurship and communication
27.1 The concept of entrepreneurship
entrepreneur ▶
An entrepreneur is someone who sets up a business, or businesses, taking on
financial risks in the hope of profit.
entrepreneurship ▶
Entrepreneurship is the activity of setting up a business or businesses and taking
on financial risks in the hope of profit.
ITQ 1
What is an entrepreneur?
Practical activity:
Create a mind map showing ways
that a farmer could generate
additional income through
entrepreneurship.
ITQ 2
Explain the difference between an
opportunity-based entrepreneur and
a necessity-based entrepreneur.
ITQ 3
Give TWO reasons why someone
would want to become an
entrepreneur.
ITQ 4
Describe THREE personality traits
required for entrepreneurship.
372
Type of entrepreneur
Opportunity-based entrepreneurs:
• create a business from an idea
• find there is a gap in the marketplace for their idea
• develop a solution to a problem and generate profit
from it.
Necessity-based entrepreneurs:
• need to find a solution to a problem, for example, a lack of
profit in the main farm business
• business is new to them, but they are not necessarily
innovative
• are able to make the new business profitable.
Example
A farmer creates a new livestock
feed for beef fattening that reduces
greenhouse gas emissions.
A farm turns the bottom of one field
into a campsite and advertises on
the internet for overseas visitors.
Table 27.1 Types of entrepreneurs.
Reasons to become an entrepreneur
There are a number of reasons why people would want to start their own
businesses and become entrepreneurs.
• Many people enjoy the freedom of managing their own time and setting their
own deadlines, as well as the flexibility to work the required hours when it
suits them.
• There is a lot of satisfaction gained from creating something from nothing and
making your own dreams come true.
• It is extremely self-fulfilling to be able to devote yourself to making money
from your own idea, which you have brought to market.
• Starting your own business is a good way to achieve financial independence.
You are paid for the work that you do and are able to set your own salary.
• While there are financial risks to setting up your own business, there can be
large financial benefits from your work, which, as the business owner, you
will receive.
• Starting your own business can be self-actualising. There will be opportunities
to become the expert in your own area and to explain concepts that you have
created to others, even solving global problems with your ideas.
• There may be opportunities to recruit and employ your own team to help
grow your business, as well as share your expertise by mentoring others.
Personality traits needed for entrepreneurship
• Entrepreneurs need to be innovative, and must be able to present a clear
vision that they believe can be turned into a viable business.
• Entrepreneurs are risk-takers and are not afraid to make mistakes. Many
more businesses fail than succeed.
• Entrepreneurs need to believe in what they are creating, and know when to
keep trying. They need to be able to make sensible, economic judgements and
know when to abandon an idea that will not make a profit.
• Entrepreneurs are people who understand other people and what they want
and need. It would be difficult to build a business without understanding the
customer who will be buying the product.
27: Entrepreneurship in agriculture
• Entrepreneurs need to have a sense of fairness, especially with the people
they deal with.
• Entrepreneurs need to be dynamic, work very hard and work well with
others. Even if they work on their own (sole trader), they will need to be able
to work with clients and network effectively within their industry.
• Entrepreneurs need to understand their abilities and limitations, and know
how to find others to learn from or get the required skills from employees.
• A new business will have many problems before it becomes profitable and
enjoys growth. To make a business successful, an entrepreneur needs to be
achievement-oriented and able to focus on both short- and longer-term goals.
Practical activities:
1. Look back at the mind map
you created in the last practical
activity. Choose ONE or TWO
ideas and write down the
personality traits that are vital
for this business to succeed
and give reasons.
2. Research awards
and programmes for
entrepreneurship in the
Caribbean.
Business / organisation
Sole trader
Partnership
Cooperative
Limited company
Franchise
State-owned enterprise (SOE)
Non-governmental organisation (NGO)
27.2 Forms of business organisations
Businesses and organisations are divided into different types. The following table
gives brief descriptions of the most common types of businesses.
Description
This is a person who exclusively owns a business. They are entitled to keep all profits after tax has been
paid, but they are also liable for all losses.
This is a legal form of business operation between two or more people who share the management and
profits.
A cooperative is a private business organisation that is owned and controlled by the people who use its
products, supplies or services.
This is a private company where the owners are legally responsible for company debts only to the extent of
the amount of capital they have invested.
A franchise business is a business in which the owners, or ‘franchisors’, sell the rights to their business
logo, name and model to third-party retail outlets, which are owned by independent third-party operators
called ‘franchisees’.
A state-owned enterprise is where the government or state has significant control in a company through
owning most of the shares. These are set up so that the state or government can embark on commercial
activities.
A non-governmental organisation (NGO) is any non-profit, voluntary citizens’ group that is organised on a
local, national or international level. NGOs perform a variety of services and humanitarian functions. They
bring citizen concerns to governments, advocate and monitor policies and encourage political participation.
Many NGOs are organised around specific issues such as human rights, the environment or healthcare.
Table 27.2 Types of business organisations.
River Antoine Estate Ltd, Grenada
River Antoine Estate Ltd is one of the oldest distillers of rum in the world.
The limited company owns 300 acres of sugar cane plantation. They also use
the produce from private farms as there is not enough sugar cane to meet
production, as demand is so high for this premium product. Rivers has 80 fulltime employees engaged in the manual production of the liquor. The rum
produced by the company is 75–88% alcohol by volume (Alc / Vol). This is for
the local or domestic market as alcohol of this strength cannot be exported
from the country. The rum produced in the dry season has a higher alcohol by
volume and a fruitier taste, whereas, in the wet season, the rum has a lower
alcohol by volume and a harsher taste. More rum is produced in the wet
season as the river is higher and the water wheel that crushes the
sugar cane rotates more quickly.
Figure 27.1 Rum factory, Grenada –
example of a limited company that
focuses on local market.
373
Section F: Entrepreneurship and communication
Each type of business has advantages and disadvantages for the entrepreneur.
Business organisation
Advantages
Sole trader
• The trader keeps all the profits.
• The start-up costs are low.
• Establishing and operating a sole trading business is simple.
Partnership
• Two people may be able to solve problems more effectively
than one person.
• More capital (and borrowing) is available for the business.
• Good-quality employees can be made partners.
• There is opportunity for income splitting. This is where
earnings and profits are paid to each partner, not necessarily
in equal amounts, based on an agreement. Sometimes this
can help the partnership to pay less tax.
• Cooperatives that are incorporated are not normally taxed
on surplus earnings (or patronage dividends) refunded to
members. Incorporation means creating a legal identity for an
organisation that is distinct from its members. This is often
called a ‘corporate body’.
• Cooperatives can more easily obtain discounts on supplies
and other materials and services, using their size.
• The democratic structure of a cooperative ensures that it
serves its members’ needs.
• The business owners will not be held personally responsible
(personal liability), as all their actions are done as agents for
the business.
• The owner of a limited company will benefit from using his or
her personal vehicle for business. The owner can charge the
mileage made on business travel to the business.
• The business name is protected by law once it has been
successfully registered.
Cooperative
Limited company
Franchise
State-owned enterprise
(SOE)
Non-governmental
organisation
• Each partner has to help pay the all the partnership’s debts.
• There is a risk of disagreements and friction among partners
and management.
• If partners join or leave, it is likely that all of the partnership
assets will have to be valued and this can be costly.
• Cooperatives may suffer from slower cash flow since a
member’s willingness to contribute depends on how much he
or she uses the cooperative’s services and products.
• While the ‘one member-one vote’ principle is appealing to
small investors, larger investors may choose to invest their
money elsewhere.
• If members do not fully participate and perform their duties,
whether it involves voting or carrying out daily operations, the
business cannot operate at its best.
• The business will need to pay corporation tax, which is a tax
on the profits of the business.
• As a limited company, there is administration that must be
attended to regularly. This includes working on tax returns,
expense details and business accounts. These usually need to
be completed every month.
• The business must publish its accounts, including the details
of corporation tax and also give a business address. This
means that all annual accounts and financial reports will be
available for the public to read.
• An entrepreneur does not necessarily need business
• Buying a franchise means entering into a formal agreement
experience to run a franchise. Franchisors usually provide the
with the franchisor.
training needed to operate their business model.
• Franchise agreements dictate how the business is run, so
• Franchises have a higher rate of success than start-up
there may be little room for creativity.
businesses.
• Bad performances by other franchisees may affect the
• It is potentially easier to secure finance for a franchise. It may
franchise’s reputation.
cost less to buy a franchise than to start a business of the
• Buying a franchise means ongoing sharing of profit with the
same type.
franchisor.
• They receive financial support from the government.
• There are strict government controls and restrictions around
general operations and decision-making.
• They often have access to favourable policies, e.g. tax
advantages on certain products.
• There is usually a strong corporate and management focus,
which does not involve and include ideas from employees.
• They have access to a large and stable potential customer
base.
• There is a strong political influence as political objectives are
important to SOEs.
• They have the ability to experiment freely with innovative
• Paternalistic attitudes may restrict the degree of participation
approaches and, if necessary, to take risks.
in programme or project design.
• They are flexible in adapting to local situations and
• There may be restricted / constrained ways of approach to a
responding to local needs. They are therefore able to develop
problem or area.
integrated projects, as well as sectoral projects.
• There may be reduced replicability of an idea, due to non• They enjoy good rapport with people and can render microrepresentativeness of the project or selected area, relatively
assistance to very poor people, as they can identify those
small project coverage, and dependence on financial resources
who are most in need and tailor assistance to their needs.
from outside the business.
• ‘Territorial possessiveness’ of an area or project reduces
cooperation between agencies, seen as threatening or
competitive.
Table 27.3 Advantages and disadvantages of business organisations.
374
Disadvantages
• The sole trader has to pay all the business debts personally.
• The ability to raise capital is limited.
• All the responsibility for making day-to-day business
decisions is the sole trader’s.
(Source: https://www.gdrc.org/ngo/advan-disadvan.html)
27: Entrepreneurship in agriculture
27.3 Establishing an agricultural enterprise
There are several steps to establishing an agricultural enterprise, and the
entrepreneur needs to follow these steps to ensure his or her idea is profitable
before spending large sums of money on setting up the enterprise.
Identifying business opportunities
Segment your customers
Through dividing the customer base into smaller groups that share common
characteristics, such as age, gender, location, lifestyle, attitude or purchasing
habits, the demand for products or services can be analysed. Each segment can
then be targeted with specific marketing, promotions and offers.
Analyse the current buying situation
Look at distribution channels, payment methods and other factors related to
purchasing to understand how customers buy products or services. How is the
brand considered in the minds of the customers? Are there alternatives that could
be offered to interest new customers? Changes in partnerships or relationships
with suppliers can often provide opportunities for entrepreneurs – allowing the
new enterprise to be in the ‘right place at the right time’.
Analyse potential competition
Research existing businesses in the market to understand what they are offering
the customers and their competitive advantage. Establish a unique selling point
for your business that will make the customers notice your business rather than
your competitors. Identify what your customers like and promote this. A change
in funding prospects, such as an increase in grant funding, may provide you with
an opportunity to get ahead of competitors if it is possible to capitalise quickly on
the funding.
Look at other markets
Exporting into other countries may open up new opportunities. Research the
competitors, local habits and the potential demand for your products or services
to increase the likelihood of success.
Jouvay chocolate
cooperative, Grenada
Jouvay Chocolate is one of a handful of chocolate producers around
the world that have set up production facilities in the nation where
the cocoa grows. Jouvay is unique in that instead of simply buying
from, or working with, local cocoa farmers, the company is owned
by local cocoa farmers (the Grenada Cocoa Association). The cocoa
farmers are the majority-owners of Jouvay and as such are able
to benefit from their hard work, with higher incomes and greater
economic security. Cocoa for production by Jouvay is produced by
hand from beans grown on cocoa trees on the estate. This manual
method is recognised as producing the highest-quality chocolate,
which is why Jouvay is a well-known brand and sold throughout the
Caribbean, as well as exported to the UK and Canada.
Figure 27.2
Cocoa production.
375
Section F: Entrepreneurship and communication
Understand changes in regulations
Changes in government or industry regulations can often open up opportunities
for entrepreneurs. Stay ahead of changes in your area to see whether your ideas
could benefit from a change. Be ready to act quickly if there is an opportunity.
Feasibility analysis
feasibility analysis ▶
Feasibility analysis is the process of determining whether a business idea is
viable.
Proposed business venture
Spending the time and resources necessary to
move forward with the business idea depends on:
Product / service
feasibility
ITQ 5
Describe how to identify a business
opportunity.
Industry / market
feasibility
Organisational
feasibility
Financial
feasibility
Yes in all four areas
No in one or more area
Proceed with business plan
Drop or rethink business idea
Figure 27.3 A feasibility analysis.
Best practices for a feasibility analysis
• Use templates / tools / surveys or any data and technology that you
find useful.
• Involve the appropriate stakeholders to get their feedback. (A stakeholder is a
person or company that has invested in a business and owns part of it.)
• Use market research to gather more data.
• Analyse the data and ask questions to make sure your data is solid.
Management feasibility
The business needs to have the skills and ability, as well as sufficient passion
to launch the idea. The solo entrepreneur or the founding team also needs to
understand the markets in which the business will participate.
Operational feasibility
The operational feasibility includes checking:
• the availability of factory or laboratory space for the business
• whether there is local or state government support
• the quality of the labour that is available as well as the willingness of highquality employees to join the business
• the quality of existing relationships with suppliers and customers
• the proximity (nearness) to other businesses for the purpose of knowledgesharing
• the possibility of obtaining intellectual property protection for ideas and
products.
376
27: Entrepreneurship in agriculture
Financial feasibility
A budget needs to be prepared that lists all the anticipated capital purchases and
operating expenses needed to generate the first amount of revenue. This will
determine whether the proposed idea is realistic after considering the total startup cash needed. The financial performance of similar businesses needs to be
researched to understand the expected short-, medium- and long-term financial
gains.
Promising business opportunities have these financial factors:
• a steady and rapid growth in sales during the first 5–7 years within a clearly
defined market segment
• a high percentage of recurring revenue (once a business wins a customer, the
customer continues to spend money on its products)
• the ability to forecast income and expenses with reasonable certainty
• internally generated funds to finance the business and sustain growth.
ITQ 6
Explain why a business would need
to carry out a feasibility analysis.
Marketing feasibility
Marketing feasibility assesses the attractiveness of the product to the target market.
The target market needs to be large enough for the proposed business to be
successful and profitable, but small enough to avoid attracting larger competitors.
Development of a business plan
A business plan is both a process and product, containing the overall vision and
mission for the business. Farm business plans include short- and long-term goals,
as well as an explanation of how to achieve those goals over the next 5–7 years.
For an already established business, a new business plan will show what is going
to happen next, and should be realistic, simple, specific and complete.
Business plans begin with a title page and a table of contents. Let us look at the
other sections that must be in the business plan.
Executive summary
The executive summary should be 1–2 pages long, and provide an overview of the
business concept, key objectives of the business and plan, ownership structure,
management team, product or service offering, target market(s), competitive
advantages, marketing strategy and a summary of the financial projections for
the business. An executive summary should be written last, after the rest of the
plan, with each paragraph being a summary of the more detailed, related section
of the plan.
Description of the company
In the overview, details about the current business’s history, vision and / or
mission, objectives, and the ownership structure should be supplied.
Products and services
This section gives an opportunity to expand on the products and services, including
features and benefits, competitive advantages and, if marketing a product, how
and where the product will be produced. The entrepreneur’s passion for the
product or service should be obvious here.
Industry overview
The industry overview is an opportunity to demonstrate the viability of the
business by discussing the size and growth of the target industry and the key
markets within it.
377
Section F: Entrepreneurship and communication
Marketing plan
This section is where the target market segments are described, along with the
competition, and describes how the proposed product or service will be different
from a competitor’s product or service. This is the place to explain the product or
service’s unique selling point (USP).
Discuss product or service pricing and promotion, including how any promotional
programmes will appeal to customers in each of the target market segments.
Provide a plan of marketing tactics, such as tradeshows, social media marketing
(for example, Facebook and Twitter), networking, and print, media and online
advertising. Include the cost associated with each tactic.
Describe how the product or service will be sold (for example, shops, online and
wholesalers), as well as the target markets’ buying cycle. This is the process that a
buyer goes through when considering purchasing goods.
Operational plan
Provide a description of the management team and how the human resources
plan will be acted on. This section is where to include details about the proposed
business location(s) and facilities, as well as a production plan (if selling a product),
and an overview of day-to-day operations.
Management structure
This section is where to explain how the business is organised, who performs
which roles and how decisions are made.
Practical activities:
1. Choose ONE of your business
ideas and prepare a business
and marketing plan.
2. Create a short video to advertise
your product or service.
Financial plan
This section of the business plan is so important, that it is worth dedicating up to
80% of the time to writing the financial plan. This should include three years of
projected financial statements, including income statements, pro-forma balance
sheets and monthly cash flow and annual cash flow statements. Summarise each
statement into a few easy-to-understand sentences and put these in a cover page
for the statements. Ensure that any assumptions used in forecasting revenues and
expenses are covered by documents.
Resources
Resources for a new farm business need to be determined. Resources include
the amount of land required to make the business profitable. There is no point
growing a new crop, or growing a standard crop in a different way, if there is
not enough quality land to grow enough crop for a financial return. Human
resources will always be required in farming. Deciding how many more people are
required at different times of the year will help a new business enterprise plan the
recruitment of more labour. Employees need to be trained and paid, which will
take time and profits from the business. Financial resources are usually known
as start-up capital. This is where money from an existing business is used or a
loan is obtained, which then needs to be repaid. Financial resources always come
with some risk. If the new business fails, the existing farm business will be short
of money or the loan will need to be repaid on a regular basis. Material resources
are the use of buildings, vehicles or equipment. These need to be funded or have
to be used from the existing business.
Acquiring financial resources is discussed in Unit 3. Financial resources are linked
in with the acquisition of land, by lease, from family, bought or rented.
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27: Entrepreneurship in agriculture
Management operations of the enterprise
All businesses have operations. In other words, this is a method of creating an
optimal output from various input sources, whether it be manufacturing physical
products or offering services. It is therefore good to be familiar with the basics of
managing these operations.
• When a product is being created, processes in manufacturing are
interconnected. All elements have to be predictable and consistent to achieve
a similar outcome in profits.
• Most success comes from maintaining records and disciplines precisely, with
only a small percentage from applying new techniques to the processes.
• Managers are expected to set the rules, and define the responsibilities of the
staff. Managers also need to check regularly whether the goals are being met.
Only in this way will the workers put in the necessary efforts.
• Varying processes has to be encouraged because, if managed well, they can be
sources of creativity.
• The passion of employees can be a major driver of business growth, and this
needs to be nurtured by the business and management staff.
• Consider the customer. Success will change over time, but always keep the
customer in mind.
• There will always be new theories and solutions, so you should not stick to
one or the other, but accept the change, and manage it for stability in the
long term.
27.4 The importance of SWOT analysis in
decision-making for agricultural enterprises
SWOT is an acronym: S stands for strength, W stands for weakness, O stands for
opportunities and T stands for threats to the business. The SWOT analysis helps to
identify the various elements of running a business. The internal factors (strengths
and weaknesses) can be altered by the entrepreneur, but the external factors
(opportunities and threats) are not controlled by the entrepreneur, although the
entrepreneur can respond to these factors positively or negatively.
ITQ 7
Internal
(a) State what SWOT stands for.
(b) Explain why strengths and
weaknesses are considered to
be internal factors.
External
Practical activity:
Develop a SWOT analysis based on
current trends for a farm business
or aspect of farming, for example,
beef cattle production or a broiler
chicken enterprise.
S = Strength
• Strengths are the strong
or positive points of the
business.
• Every business has a wide
range of strengths.
O = Opportunities
• Apart from the internal
strength, there are many
external opportunities too.
• These opportunities can
contribute to the business’s
growth.
• They can also enhance the
expansion opportunities for
the business eventually.
W = Weakness
• Weaknesses are the negative elements of
the business.
• From funding to distribution, the business
may have several weak points.
T = Threats
• Threats are the external challenges in the
business.
• They can be anything from dealing with
competition to tackling product launches.
• These can relate to sustainability issues in
the business.
• The idea is to address them appropriately
and further the business.
Table 27.4 A SWOT analysis.
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Section F: Entrepreneurship and communication
• Traditional production in the
Caribbean
• Favourable weather
• Low production costs compared to
intensive production
• Not intensive
• Preservation of native breeds
• Animals able to adapt to harsh
regions
• Control of weeds through grazing
• Creation of self-employment
opportunities
• Products are seasonal
• Weak distribution channels
• Not much help or support for
producers
• Low productivity and efficiency
• Lack of labour
• Farmer’s age
• Low levels of education
• Poor conditions for keeping animals
Strengths
S W
Weaknesses
Opportunities
O T
Threats
• Increased search for traditional
products
• Development of new production
technologies
• Possibilities of increasing
productivity and efficiency
• Maintenance of abandoned areas
• Low initial investment
• Producers’ associations to maintain
breeds and support other producers
• Reduction in fire risk
• Reduction in human desertification
Positive
• Other meat producers with
higher growth
• Lack of competitiveness
• Higher prices than other species
• Difficult access to grazing areas
• Roads crossing with grazing paths
• Few workers want jobs in
agriculture
Internal
factors
External
factors
Negative
Figure 27.4 SWOT analysis for keeping sheep and goats on a farm.
27.5 Factors that contribute to success
and failure
Factors influencing success of an agricultural enterprise
Knowledge of business
New agricultural enterprises are most successful when the entrepreneurs have
a detailed knowledge of the industry they are entering. A broad knowledge
of the marketplace and general business skills will help to avoid costs through
outsourcing. For example, the farmer will save money if he or she can run the
business website.
Development of a business and marketing plan / strategy
Spending time initially on the development of a business and marketing plan
will ensure that the business is viable and highlight any issues that need to be
addressed to maximise profit and reduce risk.
Management of financial and human resources
Money and people need to be managed appropriately and within the law. The
entrepreneur should understand his or her limitations when it comes to financial
and human resource management. If necessary, the entrepreneur should outsource
financial work to an accountant and employ a human resource professional to
handle the daily management of employees, for example, processing the payroll
and handling the employment contracts.
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27: Entrepreneurship in agriculture
Understanding and interpreting financial statements
An entrepreneur must be able to keep accurate records, understand profit and
loss accounts, and understand adequate financing and cash flow management.
Entrepreneurs can rely on accountants but accounting services are expensive
and impractical to use on a daily basis. Information on each of these aspects of
financial management can be found in Unit 18.
Favourable enabling or political environment
An enabling environment is an external factor that needs to be understood. There
is nothing an entrepreneur can do about the circumstances in which the business
operates except to be ready to react if the circumstances should change suddenly.
Examples of favourable environments are the business produces a product that
solves a national problem or the current taxation is low on the item that is being
produced.
Access to factors of production
The ability to produce a product requires access to factors of production. For a
farm enterprise, these factors include land and labour, and capital to buy buildings,
animals and feed.
Farm management
The actual management of the farm is a crucial factor in the success of an
agricultural enterprise. For example, a mixed farm that starts to grow vegetables
for six months of the year chooses crops appropriate to the soil type and achieves
a harvest 10% greater than expected.
ITQ 8
Describe a favourable environment.
Business ethics
Business ethics are the principles that guide the way a business behaves.
Businesses have to act legally, but ethical businesses go further and act morally
too. This ensures that bribery, corruption, insider trading and discrimination
are not acceptable processes in the business. Running a business ethically can
make customers choose to deal with one enterprise over another one. Nongovernmental organisations (NGOs), and charities in particular, place the ethical
enterprises they deal with above less ethical businesses even if those businesses
have cheaper products or services.
Factors influencing failure of an agricultural enterprise
Human resources management
An inability to manage workers can result in the failure of an agricultural
enterprise. Farming is hard work and if the business owner has high expectations
but is not prepared to pay workers appropriately, the workers will leave. For
example, if workers walk out during the harvest, the crop will rot in the field and
the business may fail.
Operational management
Operational management is managing the daily tasks that maintain a business.
Business success requires attention to detail and consistency. Failure is caused by
a lack of interest in or control of these daily tasks, which are the key to producing
goods of the quality and quantity needed to make a profit.
Marketing and financial failures
Marketing failures are usually caused by misidentifying the target market or niche
for the product. Failures can also result from the target market not buying the
product as expected, or the customers not buying the product a second time. The
customers buy the product only once and then return to their original suppliers.
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Section F: Entrepreneurship and communication
Financial failures come from costs that exceed profit at any point in the life of
the business. For example, in the beginning, the business plan determined that
the product was viable, but an unexpected increase in taxation on the product
reduced the profits. This prevented the entrepreneur from repaying a capital loan
that was taken out to buy machinery. The machinery was repossessed and the
enterprise could no longer produce the product.
Farm management
Poor farm management can result in the failure of an enterprise. For example,
poor animal management in a dairy enterprise can lead to the herd suffering from
mastitis. When this happens, the cows cannot be milked. As a result, the business
fails because there are substantial losses from the cows and machinery, which
would have to be paid for, but would not be productive.
Internal factors related to the enterprise
The farm business can fail on any of the internal factors relating to the enterprise.
These are listed in the SWOT analysis in the weakness section.
ITQ 9
Explain THREE internal factors that
could result in the failure of an
enterprise.
External factors related to the enterprise
External factors related to the enterprise are found in the SWOT analysis under
threats. There is little an entrepreneur can do about these factors. However, if the
entrepreneur is aware of these factors at the start, he or she can prepare a backup plan to use if any of the threats directly affect the business. An unfavourable
environment is where the business produces a product that is released at the
same time as a competitor’s product, or the taxation is increased on the item that
is being produced.
27.6 The purpose of key financial statements in
decision-making
Key financial statements help businesses with their ongoing calculations.
The statements show whether the business is still viable because they contain
information about the income and expenses of the business. The ability to
interpret business accounts accurately is particularly important if more investment
is required. Demonstrating that the current enterprise is profitable and detailing
exactly where money is being spent is a valuable skill.
Key financial statements
profit and loss account ▶
A profit and loss account in the books of an organisation are where incomes and
gains are credited and expenses and losses are debited. This provides a financial
statement showing a business’s net profit or loss over a given period.
balance sheet ▶
The balance sheet is a statement of the assets and liabilities of a business at a
particular point in time, detailing the balance of income and expenditure over the
preceding period.
cash flow ▶
Cash flow refers to the movement of money in and out of the business in terms of
income and expenditure. Ideally, a business wants a positive cash flow, meaning
that more money is coming into the business than is going out.
ITQ 10
State the THREE main financial
statements.
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27: Entrepreneurship in agriculture
The purpose of key financial statements
Financial transparency
Even the smallest numbers in a balance sheet can have a huge impact on the
business. Over time, assets lose their value so they are not as valuable as they
were when they were first purchased. This loss of value is called depreciation. A
percentage has to be deducted from their value for depreciation.
Understanding tax liability
When businesses make a lot of profit, the taxes they have to pay are equally high.
Reducing the amount of tax that needs to be paid is sometimes possible but it can
only be achieved if the business has accurate financial statements.
Correcting errors
Accurate financial statements are also essential to catch costly mistakes or internal
wrongdoing early on in the process. If any illegal activity is taking place, there
is no better way to catch it than through finding unexpected differences in the
financial figures. A business employs an auditor to check every entry in the
business accounts so that the business can find out whether anyone has done
anything illegal with any part of the business or whether an accounting error has
been made.
Building trust in the company
Accurate financial statements build investor trust in the business. Investors need
a sign that a business is doing well and they can put their hard-earned money in
the business. If the balance sheet shows a profit, investors will feel confident that
any investment they make in the business will be repaid.
Improving payment cycles
Outgoing payments, including salaries, inventory payments and creditor
payments, need to be managed. If a loan is overdue then the business needs
to know how much interest has to be paid or received. Accurate mathematical
calculations can be done only if the figures are correct.
Better decision-making and financial planning
Analysing financial statements is crucial when decisions are to be made. An
entrepreneur will look at the value of the assets currently held by the business to
decide whether the business can afford to purchase something. When the value
of the assets has depreciated a lot, the entrepreneur has to decide whether the
assets need to be sold.
A business needs funds to expand. In this situation, the accountant would look
at the debts on the balance sheet, the shareholders’ capital already invested in
the business and other loans the business has taken out and decide which type of
financing the business could afford.
Practical activity:
In groups, use internet research to
find agricultural examples of each
of the key financial statements.
Financial statements allow the business owner to make decisions and create plans
that are based on facts. The profit and loss account, balance sheet and cash flow
statements need to be examined every day to evaluate how much money the
business is making, how much money is needed and what reserves should be
built up. Added to this information are the proposals to increase sales and boost
financing.
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Section F: Entrepreneurship and communication
Revision map
Operations
Analyse the
current buying
situation and
potential
competition
Look at other
markets
Segment
customers
Identify
opportunities
Marketing
Management
Understand
changes in regulations
that may benefit
the sale of the product
or service
Entrepreneurs
may be
opportunity-based
or necessity-based
Limited
company
Franchise
Finances
SOE
Cooperative
NGO
Partnership
Different
types
Feasibility
analysis is used to
determine whether
proposed business
is viable
Sole trader
Entrepreneur
is someone who sets
up a business, taking
on financial risks in
the hope of making
a profit
Entrepreneurship
Business
organisations
Entrepreneurship
in agriculture
Cash
flow
Balance
sheet
Purpose of
key financial
statements
Importance
of SWOT for
decision-making
Factors
that cause success
of farm business
Strengths
(internal factors)
Purpose of
statements
Shows
evidence of
illegal
activity
Factors
that cause failure
of farm business
Ability to use
opportunities
(external factors)
Improves
decision-making
Opportunities
Threats
Statements
evaluated
daily
How much
money is being
made
384
SWOT analysis
assesses
proposed
business
Factors that
cause success or
failure of farm
business
Reserves
the business
needs to
build up
Builds
investor
confidence
Strengths
Weaknesses
Key
financial
statements
Profit and
loss account
How much
money is
needed
Business plan
states short- and
long-term goals and
explains how goals
will be achieved in
5–7 years
Weaknesses
(internal factors)
Inabi