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Agricultural
Science
for CSEC ® Examinations
MACMILLAN
Ronald Ramharacksingh
Series Editor: Dr Mike Taylor
Agricutural
I
Science
for CSEG ®
hmutigHs
Ronald Ramharacksingh
CSEC is a registered trade mark of the Caribbean Examinations Council (CXC).
Agricultural Science jr CSEC Examinations is an independent publication and has not been
authorised, sponsored, or otherwise approved by CXC.
MACMILLAN
Series preface
ix
About this book
x
Section A: The Business of Farming
1 The role and importance of agriculture
1.1
1.2
1.3
2
3
The importance of agriculture in national, regional and international economies
Career opportunities in agriculture
Institutions concerned with agricultural development in the Caribbean
1
2
3
7
Challenges confronting agriculture
15
2.1
2.2
2.3
16
21
26
Local and regional challenges
Issues affecting global agriculture
Terminology used in food safety, importation and certification
Alternatives to conventional farming
31
3.1
3.2
32
35
Non-conventional farming systems
The principles of organic farming
4 Economic factors of production
4.1
4.2
4.3
4.4
4.5
The economic functions of production, consumption and marketing
The factors of production
Factors of production related to agriculture
The 'law of diminishing returns'
Demand, supply and price relationships
5 Trade agreements
5.1
The effect of international trade agreements
6 Farm financing and support services
6.1
6.2
6.3
Sources of capital
Co-operatives
Incentives given to farming
7 Farm organisation and planning
7.1
7.2
7.3
7.4
Farm management and farm records
Income and expenditure
Partial and complete budgets
The relationship between budgeting and decision-making
41
42
44
45
47
51
61
62
68
69
72
75
80
81
84
86
87
Section B: Crop Production
8
Soil and soil fertility
Soil formation
8.1
The soil profile
8.2
8.3
The major components of soil
8.4
The physical and chemical properties of major soil types
8.5
The carbon and nitrogen cycles
91
92
95
96
98
104
V
Contents
8.6
8.7
8.8
8.9
8.10
8.11
8.12
8.13
8.14
The factors affecting soil fertility
Importance of minor nutrients in crop production
Fertiliser ratio
Maintaining soil fertility
Composting
Soil erosion
Different types of soil erosion
The causes of soil erosion
Soil and water conservation methods
9 Land preparation
9.1
9.2
9.3
9.4
9.5
9.6
9.7
9.8
The relationship between climate and agricultural production
Measuring rainfall and temperature
Interpreting weather records
Weather records and farming decisions
Land preparation methods
Machinery used in crop husbandry
Care and maintenance
Safety precautions when operating tools, machinery and equipment
10 Plant morphology and physiology
10.1
10.2
10.3
10.4
10.5
10.6
The structure of plants
Sexual and asexual reproduction in plants
Sexual and asexual reproduction in relation to crop production
Seed germination
Plant processes
Environmental factors and plant growth and development
11 Plant genetics, breeding and biotechnology
11.1
11.2
11.3
The principles of genetic inheritance
Plant breeding
Biotechnology in plant improvement
12 Crop husbandry
12.1
12.2
12.3
12.4
12.5
12.6
12.7
12.8
12.9
12.10
Cropping systems
Cultural practices associated with crop production
The effects of weeds on crops
Methods of weed control
Pests and crop damage
Major crop diseases
Pest and disease management
Chemicals in the environment
Cultivation of vegetable crops
Plant quarantine
13 Harvesting and post-harvest practices
13.1
13.2
13.3
13.4
13.5
Post-harvest technology
Harvesting crops
Harvesting methods
Harvest and post-harvest practices for ornamentals
From the farm to the table
14 Processing and utilisation
14.1
14.2
14.3
Vi
Reasons for processing crops
Food processing techniques
Utilisation of processed products
106
108
109
110
113
114
114
115
116
125
126
127
129
131
131
135
138
139
144
145
151
156
157
164
167
174
175
178
181
186
187
189
190
191
193
195
197
198
200
203
208
209
209
210
211
212
216
217
217
222
Contents
Section C: Animal Production
15 Morphology and physiology
15.1
15.2
15.3
15.4
15.5
15.6
The digestive system of a bird
Ruminant and non-ruminant digestive systems
Functions of the digestive system parts
The process of digestion
Digestion in rabbits
The structure of an egg
16 Nutrition
16.1
16.2
16.3
16.4
16.5
16.6
16.7
16.8
16.9
Nutrients in animal nutrition
The balanced ration
Appropriate rations for livestock
Feed conversion ratio (FCR)
The importance of FCR
Systems of grazing
The advantages and disadvantages of different grazing systems
The importance of forages in livestock feeding
Forage conservation
17 Housing
17.1
17.2
17.3
Housing requirements for farm animals
Housing for broilers, layers and rabbits
Bee production and fish farming
18 Animal genetics, breeding and reproduction
18.1
18.2
18.3
18.4
18.5
18.6
18.7
18.8
18.9
18.10
18.11
18.12
Breeds of farm animals
Uses of different breeds of farm animals
Animal genetics
Breeding systems in animal production
The advantages of cross-breeding
The principles of genetic improvement
Artificial insemination in farm animals
Advantages and disadvantages of artificial insemination
Terms used in animal reproduction
Egg formation and incubation in poultry
Embryo transfer
Genetic engineering in livestock production
19 Animal husbandry
19.1
19.2
19.3
19.4
19.5
19.6
19.7
19.8
19.9
19.10
The care of young chicks and rabbits
Management practices associated with rearing broilers, layers and rabbits
Rearing a batch of broilers
Animal health
Pests and diseases of poultry and rabbits: symptoms, prevention and control
The economic importance of bees
The types of bees in a hive
The social activities of bees
Pests and diseases of bees
Honey and other bee products
20 Animal products technology
20.1 Animal products and by-products
20.2 The dressing percentage of farm animals
20.3 The slaughter of broilers
20.4 The marketing of eggs and meat
225
226
228
228
229
231
231
235
236
238
239
240
240
241
243
244
247
252
253
254
256
263
264
265
266
267
268
269
270
271
272
274
276
278
285
286
288
289
289
290
291
292
292
293
294
300
301
304
305
306
VII
Contents
Section D: Horticulture (Double Award only)
21 Horticulture
21.1
21.2
21.3
21.4
21.5
21.6
What is meant by horticulture?
The importance of horticultural plants
The cultivation of horticultural plants
Harvesting techniques of horticultural plants
Quality requirements for flowers
The establishment of lawn and turf grasses
310
311
312
312
316
316
317
Section E: Animal Management (Double Award only)
22 Animal management
22.1
22.2
22.3
22.4
22.5
22.6
22.7
Management practices in the rearing of livestock
Preventing food spoilage
Principal cuts of meat
The quality requirements of meat
Safety requirements in the processing of food
Value-added products
The role of biotechnology in animal production
321
322
330
332
332
333
333
335
School-based Assessment (SBA) component
339
Answers to multiple choice questions
372
Index
373
VIII
This book isn't just words on a page. Here are some important features. Each
will help you, if you take advantage of it.
There are two columns. The bigger column has the text and some really large
diagrams; you can read straight down it without interruption. The smaller
column has other diagrams which the text mentions. Look at them carefully
as you need them. You may find that looking at a diagram for a few seconds
is worth a few minutes of reading.
The first time that an important new word occurs, it is repeated in the smaller
column. If you want to check what a word means, you can find it quickly.
There are questions called ITQs (In-Text Questions). When you have read the
nearby text, try to answer the question, in your head or on paper. If you can,
you're on the road to understanding. If you can't, just go back and read that
bit again. Answers to ITQs are at the end of each chapter, so you can tell how
good your answer was.
At the end of each chapter there are some examination-style questions. Your
teacher will suggest how you can use them. Some are multiple choice questions, and the answers to these can be found at the end of the book.
Whether for the Single or the Double Award, you have to present an SBA
involving practical work and the production of a record of what you have
done, including a financial analysis. The last chapter has a detailed explanation of what is expected, an explanation of how you might set about the
practical work and what is important in it.
There is a detailed index. Don't be afraid to use it to find what you want!
X
r
111111110fflus
oo
..........
e and IrilOndi10E Of
(use
By the end of
3
this chapter
you should be
understand that agriculture is important in national, regional and international
economies
3
able to:
li st the various career opportunities and levels of training in the agricultural
sector
3
know and understand the functions of local, regional and international
institutions concerned with agricultural development in the Caribbean.
Concept map
Role of agriculture
Economic importance
Regional
National
-food security
[-employnt contribution
to GNP
journalism
food production
Career opportunities
International
-foreign exchange
-trade liberalisation
agro-processing
education
certification
sales and marketing
Agricultural development
Local
Regional
Ministry of
Agriculture
-CARICOM
-CFNI
-CDB
-CARD!
-UWI
-CASE
-ECIAF
-GSA
quality control
management
International
-EU
-IICA
-FAO
-OAS
I DB
-CIDA
engineering
food inspection
services
1
Section A: The Business of Farming
1.1 The importance of agriculture in national,
regional and international economies
agriculture ►
Distinguish between 'agriculture', 'farming' and
'husbandry'.
List as many different types of agricultural
production as you can think of, focusing on those
found in the Caribbean.
The word agriculture comes from the Latin agri cultura, 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 supplying seeds, chemical
fertilisers, machinery, finance and technology. In addition, agriculture involves
marketing and processing.
Often 'agriculture' is 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 a
way of life for families in rural communities. With modern technology and a rising
world population, agriculture today is seen as an art, a skill, an applied science,
a multi-faceted discipline, a business and a vocation, focused primarily on food
production.
Foreign exchange earnings
Agriculture is very important to the economies of all Caribbean countries, both
regionally and internationally.
When Caribbean agricultural goods and services are sold to other countries,
foreign exchange ► foreign exchange is earned. For example, the export of bananas and coffee
earns foreign currency. However, when foreign agricultural goods and services
are imported, Caribbean currency is converted to 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
national economy and contributes to the GNP.
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.
In the Caribbean, food security is affected by:
• low agricultural productivity, resulting from inefficient use of water and other
inputs
• a decline in earnings from traditional crops resulting from the loss of trade
preferences
• a dependency on imported food resulting from the inability to produce food
locally at competitive prices
• increased poverty in many countries because of a loss of agricultural jobs.
Food security can be promoted by initiatives to improve food production and
marketing, expand trade opportunities, increase income and improve nutrition.
Employment ratio of imported food to local produce
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
2
1 - The role and importance of agriculture
are created. Impo rt ing food from abroad reduces the number of local ag ri cultural
jobs.
There is also concern about the quality of some of the food impo rt ed into the
Ca ribbean. It is thought that some impo rt ed food may be responsible for an obesity
problem within the population.
National and regional plans for agricultural development
agricultural plans ► Agricultural plans are policy documents, prepared by governments, private firms
or international organisations, setting 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
the areas of agriculture which need attention and may specify the current status,
constraints, strategies and resources required for the development of each area.
Carefully prepared plans can bring about agricultural development and national
development.
Regional plans for agricultural development are produced through the cooperative effo rt s of Caribbean countries, based on the agricultural needs of the
region. Specific goals, objectives, constraints, strategies, resources and evaluation
procedures help to put the plans into practice.
Trade liberalisation
Trade liberalisation helps global competitiveness. A fair trade in goods and services
tariff ► develops through removing tariffs and non-tariff bar ri ers. A tariff is a tax levied by a
government on imports (or occasionally expo rt s) for purposes of protection, suppo rt
trade liberalisation ► of the balance of payments, or the raising of revenue. Global trade liberalisation
initiatives encourage greater efficiency in marketing and trade by restructuring
trade policy regimes to reduce the level of protection from competition.
^+y'7
Trade liberalisation does not just depend on the removal of barriers and the
Make a list of the major roles of agriculture in the
negotiation of better access conditions. It requires rules which define the framework
economy of a count ryfor each government in the formulation of their trade policies. This should result in
each country being encouraged to improve productivity in agriculture and making
Q_
greater efforts to improve the quality of agricultural products.
T^
Explain what is meant by food security'.
'
How does importing food reduce the number of
job oppo rt unities?
Practical activity:
Look at some national, regional
and international statistical repo rt s
about food production, impo rt s or
expo rt s.
1.2 Career opportunities in agriculture
Careers in agriculture include:
• food production
• sales and marketing
• services
• food inspection and quality control
• agro-processing
• engineering
• education
• journalism
• management and administration
• certification.
Some career areas extend beyond the agricultural sector: sales and marketing,
services, engineering, management and administration can all be associated with
many other industries.
3
Section A: The Business of Farming
Food production
The most specialised careers in agriculture are associated with the production of
crops and the raising of livestock (see Table 1.1).
Occupation
Labourers
Job description
Unskilled workers who work for farmers; involved in
ploughing, planting, harvesting, looking after animals,
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 land and resources,
Overseers/
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.
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
farmers need to be more productive. They provide a means of
communication between researchers and farmers.
These include: engineers developing new farm machinery;
chemists developing new fertilisers and pesticides; biologists
researching new breeds of animals and new types of crop
plants. Research is carried out in laboratories and institutes,
employing other staff such as laboratory technicians,
Figure 1.1 shows research workers in the field.
Vets care for sick animals and are also responsible for testing
for diseases in animals. Veterinary nurses help the vets in
their work.
Extension
officers
Research
workers
Veterinarians
(vets)
Agricultural
engineers
Viticulturists
Plan, supervise and manage the building of agricultural
projects, including drainage schemes, food processing
plants and structures for housing livestock. Many work for
government agencies or are involved in research which
involves designing new agricultural equipment.
Specialists in managing vineyards; require a knowledge of
grapes, their growing conditions, when to harvest and prune.
Can be involved in research developing new techniques for
culturing vines and breeding new varieties,
Qualifications needed
A basic knowledge of tools and machinery is
useful to gain employment. An NVQ level 1
qualification could be helpful.
Farmers need a basic knowledge of
agriculture, the use of tools and machinery
and the ability to keep records and to
control their finances. They need training to
secondary level, studying to NVQ level 2 or
CXC in Agricultural Science.
Overseers and managers need the same skills
as farmers, together with the ability to deal
fairly with the workforce (the labourers).
Diploma, Associate Degree or Bachelors
Degree in Agriculture.
Usually a research worker will have a
university degree in a science subject, e.g.
Biology, Chemistry, Physics or Engineering.
Laboratory staff are trained to secondary
level and have good grades in CXC science
subjects.
Vets need a university degree in Veterinary
Medicine.
Veterinary nurses need qualifications: at least
CXC in science subjects.
A university degree in Engineering.
Need a basic knowledge of agriculture, with
specialist knowledge of grapes. Qualifications
vary from diploma level to a university
degree in Horticulture or an agricultural
subject, depending on level of responsibility.
Table 1.1 Some careers in food production.
Sales and marketing
Agricultural produce is sold in shops, supermarkets or on market stalls (see
Figure 1.2). It usually has to be transported from farms to the wholesalers and
from there to retailers and other outlets. All this involves loaders and drivers.
At the wholesalers, produce may be stored for some time, providing employment
for storekeepers, clerks and security officers.
Managers, cashiers and sales personnel become involved when produce reaches
the shops.
Figure 1.1 Agricultural scientists
carrying out some field tests on plants.
4
1 • The role and importance of agriculture
Services
The jobs associated with servicing any industry include technicians, drivers,
electricians, plumbers and mechanics. Very few of these jobs require specialist
knowledge of agriculture, although some mechanics and technicians may develop
expertise in dealing with agricultural machinery.
Food inspection and quality control
These are very important aspects of food production, both for fresh produce and
for processed food. Lack of inspection and poor quality control procedures result
in inferior produce and health hazards. Careers in these areas require training
and qualifications to at least NVQ or equivalent level. Qualified people may be
employed in agro-processing or by government agencies.
Agro-processing
Figure 1.2 An agricultural market
stall.
Agro-processing involves turning agricultural produce into products (preserved
fruits, jams, wines and sauces), which can be marketed locally, nationally or
exported. The employment opportunities are numerous. They range from unskilled
labour (in processing and packaging plants) to biochemists and quality assurance
officers who have professional qualifications.
Engineering
Agriculture depends on mechanisation to become more efficient. Transport of
produce and animals from farms to processing plants is essential and increasingly
processes are becoming mechanised. Harvesting of many crops is done by
machinery, rather than by hand. Ploughing, sowing, spreading fertilisers and
spraying with pesticides can all be done mechanically, thus saving time and
reducing the cost of labour.
Engineers are employed to develop and maintain machines. New techniques
in processing and preserving food require machines which are designed and
manufactured by engineers.
Education
Education is vital to agriculture at all levels
— from schools to colleges and institutes,
through to university. In schools, pupils
are made aware of agriculture and
the environment (see Figures 1.3 and
1.4). Figure 1.4 on page 6 shows a land
laboratory in a school. This is an area
where many different types of crops are
grown.
Figure 1.3 An agriculture teacher and her students examining a mango tree.
5
Section A: The Business of Farming
Figure 1.4 A land laboratory (secondary school).
Agricultural Science is a core subject
in junior secondary schools, laying
a foundation for further agricultural
training. In senior secondary schools,
different agricultural courses are offered.
Some students prepare for Agricultural
Craft subjects; others prepare for the
Caribbean Examination Council (CXC)
Agricultural Science qualifications.
Vocational courses, such as associate
degrees in Agriculture and Forestry,
are offered at the Eastern Caribbean
Institute of Agriculture and Forestry
(ECIAF) in Trinidad and Tobago and at
other institutions in Jamaica, Guyana
and St Lucia. In Trinidad and Tobago,
the Ministry of Agriculture, through the
Extension Services, offers a wide range of
short courses for farmers.
The University of the West Indies
( UWI) offers degree courses in many
agricultural and associated topics. There
are also opportunities for postgraduate
training leading to higher degrees. There
are job opportunities for well-trained
teachers, together with support staff, in
all these institutions.
Journalism
Journalism in the agricultural sector can suit those who write clearly and have an
interest in agriculture and the environment. Journalists contribute to agricultural
journals and magazines, government documents, information leaflets and
instructions. Photography and graphic design also provide rewarding careers.
Qualifications vary, but experience and a detailed knowledge of the subject matter
are essential.
Management and administration
Make a list of the personnel required to organise
and run a retail outlet selling agricultural produce.
A farmer has a contract to supply a supermarket
chain with salad vegetables. Make a list of the
different jobs involved in harvesting, packaging
and transporting his produce to the supermarket.
Practical activity:
Choose a career or career area
that interests you. Investigate
the qualifications required and
employment opportunities
available.
6
Businesses and organisations require good management, so managers and
administrators are needed in all sectors of agriculture. Small farms can be run by
a farmer, but large farms employ managers to take charge of the organisation of
labour and resources. There will be employment opportunities for administrators
and managers in all other aspects of the industries and institutions associated with
the agricultural sector. For example, wholesale and retail outlets, schools and
colleges need administrative staff at all levels, including secretaries and accountants.
Certification
Qualifications are important in any career and can lead to employment at a higher
level. Many schools and colleges organise courses leading to qualifications in the
agricultural sector. On completion of the course and following an examination,
these institutions issue certificates, diplomas or degrees stating the level of expertise
reached. In schools, examinations are organised by the Caribbean Examinations
Council. In other institutions, the examinations are organised by the college or
university. All these examinations are set and judged by experts with a good
knowledge of their subject. To gain employment in this area, years of experience
of teaching the subject are required.
1 •
The role and importance of agriculture
1.3 Institutions concerned with agricultural
development in the Caribbean
Local institutions
Local institutions, both governmental and non-governmental, are essential for any
modem agricultural economy. The quality of the support mechanisms determines
the quality of the agricultural output. More importantly, it creates a sound
foundation for new initiatives, growth and expansion in the agricultural sector.
Each Ministry of Agriculture is divided into several divisions which work in
collaboration with affiliated 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
consists of 11 divisions (see Table 1.2, overleaf), each having responsibilities for
different aspects of agriculture, planning and training.
r:
What are the functions of the Forestry Division of
the Ministry of Agriculture? (see Table 1.2)
What are the functions of the Extension, Training
and Information Division? (see Table 1.2)
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.
Figure 1.5
An agricultural research station dealing with livestock improvement.
A demonstration farmers are shown how to carry out
a procedure.
Figure 1.6
7
Section A: The Business of Farming
Name of Division
Functions
Planning Division
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Project
Implementation
Unit
Land Administration
Division
Research Division
(see Figure 1.5,
overleaf)
Agricultural
Engineering
Division
Agricultural Services
Division
Forestry Division
Fisheries Division
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Extension, Training
and Information
Division
(see Figure 1.6,
overleaf)
Animal Production
and Health Division
Regional
Administration
Divisions (North/
South)
•
•
•
•
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
co-ordinate 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 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, mango, avocado, sapodilla and
pommecythere
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 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
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 lo cally at Chaguaramas, Trinidad
Table 1.2 The functions of the divisions of the Ministry of Agriculture, Trinidad and Tobago.
8
1 • The role and importance of agriculture
Regional institutions
There are many institutions in the Caribbean concerned with agricultural
development. Some give advice and support, whilst others provide specialised
training for careers in the agricultural sector.
The Caribbean Community
Caribbean Community The Caribbean Community (CARICOM) is an organisation of 15 Caribbean nations
(CARICOM) ► and dependencies. It promotes economic integration and co-operation.
CARICOM carries out these functions:
• co-ordinates economic policies and development planning
• sets up special projects for less-developed countries
• operates as a regional single market for many of its members (Caricom Single
Market)
• handles regional trade disputes.
The Caribbean Food and Nutrition Institute
Caribbean Food and Nutrition The Caribbean Food and Nutrition Institute (CFNI) aims to describe, manage and
Institute (CFNI)
prevent nutritional problems facing Caribbean countries. It runs training courses,
►
conducts research programmes on food and nutrition and maintains a library.
Research areas include:
• reduction of under-nutrition in children
• prevention and control of diet-related chronic diseases
• control of iron deficiency anaemia
• i mprovement of household food security.
The Caribbean Development Bank
Caribbean Development Bank The Caribbean Development Bank (CDB) assists Caribbean nations in financing
(CDB)
projects for its members. Its purpose is to contribute to the economic growth and
►
development of member countries and to promote economic co-operation and
integration.
Its main functions are to:
• assist members in the co-ordination 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.
The University of the West Indies
University of the West Indies
The University of the West Indies (UWI), Faculty of Science and Agriculture,
(UWI) ► offers a wide range of courses leading to qualifications (from diplomas to postgraduate degrees). Qualifications can be obtained in Natural Sciences, such as
Life Sciences and Chemistry, and aspects of agriculture, such as Animal Science,
Food Production, Economics and Extension Services. In addition, research units
investigate specific problems relating to crop and livestock production.
9
Section A: The B usiness of
Farmjn.,
Section A: The Business of Farming
Caribbean Agricultural Research
and Development Institute
(CARDI) ►
College of Agriculture, Science and
Education (CASE) ►
Practical activity:
Imagine that you are an
entrepreneur and wish to establish
a forestry business. Work out
which institutions you would need
to consult in order to finance it
and find suitably qualified staff.
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 soils
management
technology services, e.g.
Figure 1.7 Goat rearing (a CARDI project).
the supply of quality
plant products and
genetic products and services
market research and statistical services
business development and consultancy.
The College of Agriculture, Science and Education
The College of Agriculture, Science and Education (CASE), in Jamaica, is a multidisciplinary tertiary level educational institution offering 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.
The Eastern Caribbean Institute of Agriculture and Forestry
Eastern Caribbean Institute of The Eastern Caribbean Institute of Agriculture and Forestry (ECIAF) provides
Agriculture and Forestry (ECIAF) ► courses that last two years and lead to diplomas in Agriculture, Forestry and
Agricultural Education. Completion of a diploma enables students to gain
employment in agriculture, forestry or education, or to enter other courses in
higher education if they wish to.
Guyana School of Agriculture
( GSA) ►
T
8
What is the role of the University of the West
Indies in agricultural development in the
Caribbean?
10
The Guyana School of Agriculture
The Guyana School of Agriculture (GSA) provides training to certificate anc
diploma level in agriculture. The one-year course leading to a certificate in Forest»
trains students to become forestry technicians and teaches them the principle
of sustainable forestry. A two-year certificate course equips young people fo
careers in farming. The diploma courses last for two years and lead to careers a
Agricultural Science teachers or agricultural field assistants. These courses are ii
Agriculture, Animal Health, Veterinary Public Health and Livestock Productio
and Management.
1 • The role and importance of agriculture
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.
The European Union
European Union (EU) ► In October 2008, the 27 members of the European Union (EU) and 15 Caribbean
nations signed an Economic Partnership Agreement (EPA). It included measures
to stimulate trade, investment and innovation, and to promote sustainable
development, build a regional market among Caribbean countries and help
eliminate poverty. The effect will be to open up markets for produce from the
Caribbean countries by removing tariffs and encouraging trade liberalisation. The
agreement is important for the economies of Caribbean countries and encourages
fair trade for commodities such as sugar, coffee and bananas.
The Inter-American Institute for Co-operation on Agriculture
Inter-American Institute for
The Inter-American Institute for Co-operation on Agriculture (IICA) is an
Co-operation on Agriculture institution for agricultural research and graduate training in tropical agriculture.
(IICA) ► It was founded in response to changing needs in the Americas and has evolved
into an agency for technical co-operation 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.
The Food and Agriculture Organisation
Food and Agriculture Organisation The Food and Agriculture Organisation (FAO) of the United Nations leads
(FAO) ► international efforts to defeat hunger. It helps countries to modernise and improve
agriculture, forestry and fisheries practices and ensures 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 co-operation.
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 Organisation of American States
Organisation of American States
( OAS) ►
The Organisation of American States (OAS) is made up of 35 independent nations
of the Americas. It was founded in 1948 with 21 members, but expanded to include
the independent Caribbean nations. The goal of member nations was to 'achieve an
order of peace and justice, to promote solidarity, to strengthen collaboration, and
to defend sovereignty, territorial integrity and independence'. It seeks to promote
economic, social and cultural development and to eradicate extreme poverty.
11
Section A: The Business of Farming
The Inter-American Development Bank
Inter-American Development Bank The Inter-American Development Bank (IDB) is an international organisation
(IDB) ► 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 others 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.
The Canadian International Development Agency
Canadian International The Canadian International Development Agency (CIDA) is the federal body that
Development Agency (CIDA) ► funds assistance to developing countries in the form of goods, services, the transfer
of knowledge and skills, and humanitarian relief in emergencies and for natural
disasters.
CIDA advises on many topics including:
• food
• nutrition
• agriculture
• rural development
• fisheries
• co-operatives
• forestry
• water management
• the environment
• health and population.
r
Explain what the following sets of initials
represent: II CA; FAO; CIDA.
How is the European Union concerned with
agricultural development in the Caribbean?
Practical activity:
Choose one of the international
institutions and find out more
about its impact on agricultural
development in the Caribbean
using the Internet. 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.
12
1
Experts broaden the scope of the CIDA beyond financial support and help
developing countries to take charge of their own economies. In addition, skilled
workers and technicians are sent to developing countries. Trainees may also take
up scholarships in Canada.
CIDA funds many projects, such as:
• providing supplements to children with vitamin A deficiency
• global immunisation programmes
• supporting HIV/AIDS prevention, education and care.
• Agriculture covers a wide range of subject areas and is therefore a 'multi-faceted
discipline'.
• Agriculture is a key sector of the Caribbean economy. It makes a significant
contribution to the GNP and to foreign exchange earnings.
• The production of food locally is encouraged so that more opportunities for
employment are created.
• Careful planning is needed to bring about agricultural development and boost
the national economy and regional economy.
• Global trade liberalisation encourages improvement in agricultural productivity,
greater efficiency in marketing and fair trade for goods and services.
• There are many career choices in the agricultural sector; there are employment
opportunities for skilled and unskilled people in all aspects of food production
and marketing.
• The Ministry of Agriculture in each Caribbean country, together with other
agencies and institutions, provides support services for agricultural development.
• In the Caribbean, there are institutions providing advice and support to the
agricultural sector, as well as some which provide specialised careers training.
• Caribbean countries are part of the global economy; their agricultural
development depends on contributions from international organisations.
1 The role and importance of agriculture
ITQl
'Agriculture' is the general term used for food production and its
associated activities. Traditionally, the term was used to describe the
tilling of the soil, but it now includes the cultivation of crops, the rearing
of livestock and related industries such as technology, processing and
marketing. 'Farming' is also used as a general term, but is usually
qualified to describe the type of farming: dairy farming, organic farming,
mixed farming. 'Husbandry' describes a specialisation in growing crops
(crop husbandry) or raising animals (livestock husbandry).
ITQ2
This list can be extensive: bananas, maize, sugar cane, etc. It would be
useful to make a list for your area of the Caribbean.
1103 The major roles of agriculture in the economy of a country are: food
security, foreign exchange earnings, contribution to GNP, employment,
trade liberalisation.
ITQ4 Food security is encouraging self-sufficiency by promoting and improving
food production and marketing. This will expand trade opportunities,
increase the national income and improve nutrition. Food security should
reduce dependence on imported foods by promoting the development of
food production locally.
ITQ5
Growing food locally reduces the need for imported foods. It provides
employment for farmers, labourers, engineers and in agro-processing.
Importing food cuts down on the number of jobs in farming and
associated industries.
ITQ6
Running a retail outlet selling agricultural produce will require: a
manager, an accountant, cashiers, sales assistants, cleaners and drivers.
IT07
Supplying a supermarket chain with salad vegetables would involve:
labourers to harvest vegetables, personnel to sort, clean and grade the
produce, packers, drivers to transport the produce, engineers to service
the vehicles and machinery needed, office personnel to take and process
the orders.
ITQ8 The Forestry Division manages forest reserves, carries out reafforestation,
issues permits for hunting, sells forest plants and harvested timber,
provides technical advice and information to farmers.
ITQ9 The Extension Training and Information Division runs agricultural courses
at Farmers' Training Centres, provides technical advice to farmers, and
publishes technical information bulletins and factsheets on crops and
livestock.
ITI:11 0 The University of the West Indies provides a number of courses which
lead to qualifications in agriculture and agricultural development. It
trains scientists and engineers and there are research units investigating
problems relating to crop and livestock production.
IT011 HCA is the Inter-American Institute for Co-operation on Agriculture.
It carries out agricultural research and graduate training in tropical
agriculture.
FAO is the Food and Agriculture Organisation of the United Nations. It
helps countries to improve their agriculture, forestry and fisheries.
CIDA is the Canadian International Development Agency which funds
assistance to developing countries. It provides technical assistance and
advice on a wide range of issues.
IT012 The European Union has an agreement with 15 Caribbean nations (the
EPA or Economic Partnership Agreement) to stimulate trade. It should
open up markets for produce from the Caribbean countries by removing
tariffs and encouraging trade liberalisation.
13
Section A: 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. You can check your answers on page 372.
1. An extension officer:
A carries out research on new pesticides
B treats sick animals
C is a direct link between the farmer and the agricultural research centre
D cultivates land for growing crops
2. 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
3. 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
4. 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
5. Explain how foreign exchange can be earned from agriculture in the
Caribbean.
6. Describe the job of a farmer and outline the desirable qualifications.
7. Explain why food inspection and quality control are important aspects of
food production.
8. Outline the work of the Animal Production and Health Division of the
Ministry of Agriculture.
9. What are the functions of CARICOM?
10.Describe how regional agricultural projects are funded.
14
1100 1011
...............
21g03 Confron
dgilnIt m
By the end of
this chapter
you should be
able to:
3
3
3
explain the factors which affect local and regional agriculture
understand the major issues that could possibly affect global agriculture
know the terminology used in food safety, importation and certification
exercises.
Concept maj.D
:
Local and regional issues
Biodiversity
Topography
Global warming
Extension services
Land tenure
-
Food safety
Climate
Infrastructure
-
Global issues
Bio-terrorism
Food security
Good Agricultural
Practices (GAPS)
Good Manufacturing
Practices (GMPs)
HACCP (Hazard
Analysis Critical
Control Point)
Environmental
degradation
Praedial larceny
Food safety
Environment
Natural disasters
-
Gender issues
—
Sustainable land use
15
Section A: The Business of Farming
2.1 Local and regional challenges
The major challenge confronting agriculture is to feed an ever-increasing global
population whilst preserving, as far as possible, the natural environment. Improved
methods of crop production and livestock husbandry can result in higher yields,
but these have to be balanced against environmental degradation. In this chapter,
local and regional issues are considered — together with worldwide challenges such
as global warming and maintaining biodiversity.
In the Caribbean, agriculture is an important part of the economy and a major
activity. It is the main livelihood of people in rural districts. Traditional methods
of agriculture are labour intensive and time consuming. Any movement towards
mechanisation will result in a more financially rewarding industry. In this chapter,
we consider some issues which affect the progress of agriculture in our area.
Climate
climatic conditions ► Agricultural production is directly affected by climatic conditions. For any period,
production may be high or low depending on the weather conditions. There
are two distinct seasons: a dry season and a wet season, although the months
comprising the two seasonal periods vary slightly in some Caribbean states.
In the dry season, there is plenty of sunshine, high temperatures and a shortage
of water, especially for crop irrigation. As a result, crop cultivation is not possible
in areas where there is no water.
The wet season has heavy rainfall, cool temperatures, high humidity. and strong
winds, including hurricanes. Farmers are challenged to control pests and diseases,
which are more common during the rainy season. In addition, crops and livestock
are damaged by floods and strong winds.
Strategies for coping with climate
• In the dry season, farmers conserve soil water by cultural practices, such as
How can farmers conserve water during the dry
season?
Describe THREE ways in which crops can be
protected from wind disasters.
organic mulching, incorporating pen manure and other organic matter into
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 practise pruning and staking of crops.
• Governments can assist farmers, by means of subsidies, to establish ponds
to reduce the disastrous effects of flooding and to store water during the dry
season.
• Similarly, governments, through the Forestry Division, can help farmers to
establish wind-breaks in areas where crops are prone to wind disasters.
Topography
topography ► The topography, or external features of the land, affects methods of cultivation
and crop production. Farmers prefer to cultivate land which is flat or undulating
because movement of machinery and equipment for land preparation, crop
harvesting and transportation of produce is easier. However, most of the Caribbean
Figure 2.1 Hilly terrain — machines are difficult to operate in these areas.
16
2 • Challenges confronting agriculture
Explain why farming in mountainous areas is
more difficult than farming in flat countryside.
Explain why the mechanisation of farming in the
Caribbean is limited.
Practical
ivity:
Visit a local farm and list all the
machinery available and in use.
Make another list of jobs which
could be done more efficiently if
the farmer was able to purchase a
machine to perform the task.
is hilly or mountainous. There are no alternatives to the use of manual methods
for most field operations in hilly areas.
Mountainous areas have shallow topsoil and are prone to soil erosion and
landslips. Farmers can carry out strip cropping, cover cropping, contouring and
terracing (see Chapter 12). However, these options are not always easy. The
erection of barriers of stone, wood or grass is expensive, although these can help
to control soil erosion.
Mechanisation in hilly areas
Mechanisation allows farmers to complete agricultural tasks more speedily and
efficiently. This increases their production and profitability. However, in the
Caribbean there is limited use of mechanisation due to hills and mountains.
There is some use of machinery: the sugar cane and rice industries in Guyana and
Trinidad and Tobago are fully mechanised. Limited use is also made of machinery
in land preparation, milking cows, plucking chickens, application of pesticides,
weed control and crop irrigation.
Across the Caribbean, regional governments and private firms need to introduce
mechanisation. This mechanisation should be appropriate for the terrain and
reasonably priced for farmers.
Rural infrastructure
infrastructure ►
rural-to-urban drift ►
What basic facilities does a rural community need
to provide a satisfactory lifestyle for farmers and
their families?
In the Caribbean, rural communities have often developed into villages and towns
as a result of agriculture. Sometimes the infrastructure has been developed on a
planned basis to help farming communities. Infrastructure refers to the basic services
and installations needed for a community to function, such as transportation and
communications systems, water and power lines, and public institutions including
schools.
However, nationally and regionally, many rural areas still lack an essential
infrastructure. Often there is no incentive for farmers to continue living in these
areas, where they experience hardship because of few basic amenities. Roads, a
water supply, electricity and telephones, educational, medical and recreational
facilities all need to be available. Many rural areas lack shops and public transport
systems.
Farmers want their families to have a better lifestyle and therefore they often
migrate to urban areas. This rural-to-urban drift causes abandonment of agricultural
land, absentee farmers, a shortage of agricultural labour and a lowering of
agricultural production. The governments of Caribbean countries need to address
the needs of farmers in rural communities. Investment in rural infrastructure is the
pathway to greater agricultural productivity and food security.
Figure 2.2 An example of rural infrastructure — modern buildings in a rural area.
17
Section A: The Business of Farming
Extension services
There is a worldwide pool of technical knowledge about agriculture, gained
from developments in science. This knowledge can be used to help agricultural
development and food security. With modern communication links and internet
Why are the extension officers important to
farmers?
services, many regional territories have websites from which farmers can access
technical agricultural information.
extension officers ► Throughout the Caribbean, extension officers make farmers aware of the latest
developments in agriculture and encourage them to adopt modem technology.
In some countries there are not enough extension officers. In addition,
training centres are not always equipped to provide the training and practical
Why are farmers reluctant to use new technical
demonstrations needed to convince farmers of the benefits of new practices. This
knowledge? How can the problem be resolved?
results in reluctance to use new technical knowledge without first seeing whether
it will really work. Local and regional governments need to train more extension
officers and provide well-equipped training centres.
Praedial larceny
praedial larceny ► Praedial larceny is stealing agricultural produce, such as crops and livestock, and
it causes severe economic losses to farmers. This crime deprives farmers of the
opportunity of harvesting what they have planted and nurtured and robs them
of hard-earned dollars. This is a problem, especially for farmers who cultivate
crops which are easy to harvest (for example, bananas, watermelons, pumpkins,
cabbages, corn and cucumbers). Often, farmers or other family members have to
stay on the farm day and night, or hire a security officer.
The culprits are not always caught. In addition, complaints to the police do
not always yield a desirable response. It may be difficult to identify offenders and
bring them to justice. The few who have been caught in the act have had low
fines imposed by the courts. As a result, some farmers, especially those regularly
targeted, have given up commercial farming.
Figure 2.3 Guarding produce against praedial larceny (top); the thief makes his
escape (below).
18
2 • Challenges confronting agriculture
Local and regional governments need to address the problem with strategies
such as:
• hiring praedial larceny officers (estate police) or encouraging farmers'
What is praedial larceny?
Suggest THREE ways by which praedial larceny
can be reduced.
land tenure ►
tenant farmers ►
co-operatives to hire praedial larceny officers
• conducting regular police checks in rural districts
• imposing more severe fines on offenders
• raising public awareness of this crime.
Land tenure systems
large parcel
of land
Land tenure refers to the rights and
conditions under which people hold,
smaller
parce'
own, use, control and enjoy property
parcel
parcel
(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,
sub-division of the land has resulted
non-economically viable farming units
in fragmentation (see Figure 2.4).
Often parcels of land have become too Figure 2.4 Land fragmentation
small to be run as economically viable (land is handed down through the
generations).
farming units.
Some landowners are not interested in farming the land themselves, but allow
farmers to rent it or enter into a share-cropping arrangement. The farmers who
rent the land are known as tenant farmers. Tenant farmers are not always keen on
managing the land properly or carrying out soil improvements, because the land is
not their own and they can be evicted at short notice.
Loss of agricultural land
I I
Explain the meaning of land tenure',
In the Caribbean, land is a symbol of economic power. As time passes, land often
appreciates (rises) in value; it may be used for commercial purposes and housing,
provided that approval is granted by the government. Land is a scarce resource: it
warrants careful use and land reform policies for state lands and areas that are idle
or abandoned by their owners.
Each Caribbean state needs to ensure that agricultural lands are identified and
mapped out, and also allocated by means of 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.
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 ► Sustainable land use is a term which 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
I
international organisations with farming and forestry communities has been
State THREE ways in which management of land
proposed. The partnership will look at integrated land use management, appropriate
resources needs to be improved,
technologies, food security, economic development, and environmental protection.
19
Section A: The Business of Farming
Environmental issues
Farmers interact with the natural environment by removing vegetation, tilling the
soil, introducing new plant species, spraying with pesticides and modifying microclimatic conditions. Although necessary for food production, environmentalists
worry about the harmful effects of these farming practices.
The major concerns relevant to agriculture are:
• destruction of ecosystems
• loss of biodiversity
• build up of pollution
• pesticide resistance.
Food safety
Explain why food safety is a major challenge
affecting agriculture.
More people now travel within the Caribbean region and all over the world for
business and pleasure. Some may visit farms abroad and inadvertently bring
seed, plant, soil or animal materials into their home country. These materials may
harbour pests and diseases which can spread rapidly and cause havoc to domestic
agriculture.
Nationally and regionally, sanitary and phyto-sanitary (SPS) certification procedures govern the import and export of plants, animals and their products.
Normally, licences are issued for import and export purposes. Incoming plants and
animals are quarantined for observation, testing and certification of their diseasefree status before release for propagation in the country.
Governments sometimes impose restrictions on the import of certain agricultural
products, such as poultry (chickens, eggs) and beef, from countries which 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 their home
country.
Natural disasters
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 occurred in the last 30 years. Disasters have
cost the region billions of dollars and damaged economic health and development.
The Caribbean Disaster Emergency Response Agency (CDERA) has developed
y
a strateg for the management of such disasters, known as the CDM (Comprehensive Disaster Management) strategy. This
places emphasis on the benefits of strengthening
the infrastructure so that installations are as stormresistant 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 — this is always a challenge.
Gender issues and agriculture
Figure 2.5 Damage to maize and palm trees following a hurricane.
20
During the colonial era, women in Caribbean
countries were paid lower agricultural wages than
men (for the same number of hours and type
of work). In addition, women were barred from
holding managerial positions in the agricultural
sector as well as in other occupations. At that time,
2 - Challenges confronting agriculture
I
What do you understand by the term gender
equality?
Describe ONE way in which women might be
discriminated against in agricultural jobs.
men saw themselves as being superior to women, who played subservient roles in
the home and workplace. Most men felt that it was demeaning to take orders from
a woman boss or to work under her leadership.
In most Caribbean territories, gender issues have been addressed. Although
resistance still exists, gender equality is advocated with respect to all occupations,
including those which were formerly thought of as exclusive to women, such
as nursing, home economics, dressmaking and cosmetology. In the agricultural
sector, jobs are advertised seeking persons who possess the requisite qualifications,
knowledge, skills and experience, regardless of gender. Of course, where heavy
manual labour is concerned the employer is free to select the best person for the
particular job.
2.2 Issues affecting global agriculture
globalisation ► Globalisation has revolutionised agriculture. It is the process of increasing
What are the benefits of globalisation to farmers?
the connectivity and interdependence of the world's markets and businesses.
Globalisation offers farmers access to world markets. Aircraft can now deliver fresh
agricultural produce to the industrialised countries from almost anywhere in the
world in a single day. In addition to trading opportunities, globalisation allows
farmers to access information about new production techniques.
Many issues affect agriculture worldwide. Some of these also affect countries of
the Caribbean and they are outlined below.
-
Biodiversity
biodiversity ► Biodiversity is the variation of life forms (plants and animals) on Earth and the
many different habitats (ecosystems) in which plants and animals live together.
It is often used as a measure of the health of biological systems. The biodiversity
found on Earth today is made up of many millions of biological species, the product
of nearly 3.5 billion years of evolution.
Three levels of biodiversity have been identified:
• genetic diversity — the diversity of genes and organisms
• species diversity — the populations of organisms in an ecosystem
• ecosystem diversity — the range of habitats on Earth.
Distinguish between genetic, species and
ecosystem diversity.
Natural vegetation, such as forest, is often cleared for agricultural purposes; this
results in loss of ecosystems with their associated plants and animals. There is
worldwide concern about the loss of natural ecosystems in the quest to increase
food production and clear land for building. Loss of biodiversity results from
changes in terrestrial (land), marine and freshwater ecosystems.
Biodiversity also affects air quality, climate and erosion. It is important for
countries to conserve biodiversity through public education and awareness.
Global warming
The Earth is surrounded by a blanket of air known as the atmosphere, which is
made up of many gases. Two of these, carbon dioxide and methane, are called
greenhouse gases ► greenhouse gases. In a greenhouse, the glass roof and walls trap the heat energy
of the sun and keep it within the greenhouse. A warm temperature is maintained
and the enclosed plants thrive.
Carbon dioxide and methane in the atmosphere act rather like a greenhouse,
greenhouse effect ► 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 into space. The
greenhouse gases in the atmosphere trap the energy and keep it in, warming the
air beneath and enabling all forms of life to survive. If this energy was not trapped,
it would be too cold to sustain life on Earth.
21
Section A: The Business of Farming
heat energy radiated into space
incoming
heat
energy
atmosphere
• greenhouse gases
I • methane
carbon dioxide
• trapped heat energy
creased production of greenhouse gases
(carbon dioxide and methane) by:
• combustion engines
• industry, bush fires
• farm animals, hu
• burning fossil
some heat energy
absorbed by the Earth
Earth's surface
some heat
energy
re-radiated
back from
Earth
Earth warmed: global warming
Figure 2.6 The greenhouse effect and global warming.
Explain what is meant by global warming.
What is the relationship between global warming
and greenhouse gases?
Within the last century, there has been an increase in the production of greenhouse
gases due to human activities. Increased industrialisation, motor transport,
aeroplanes, the burning of garbage, bush fires and deforestation all contribute to
carbon dioxide in the atmosphere. This means that more heat energy is trapped
within the Earth's atmosphere, resulting in global warming.
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 favour the growth of some crops but harm
others
• more drought, affecting water availability for both domestic and agricultural
use
• more hurricanes, which may have greater strength and cause havoc to crops
and livestock
• a rise in sea temperature, causing changes to coral reefs, fisheries and other
marine organisms
• loss of habitats and diversity, with loss of plants and animals due to more
stormy weather.
Bio-terrorism
bio-terrorism ►
Bio-terrorism is the intentional use of micro-organisms to bring about ill-effects or
death to humans, livestock or crops. Agriculture is a perfect target for bio-terrorism
because an attack on food supplies affects food stores, restaurants, suppliers and
consumers as well as farmers. All countries need to be prepared for the possibility
of an attack on crops, livestock or humans.
Diseases useful to bio-terrorists
• Smallpox is a viral disease that can be fatal. In 1980, the disease was eradicated
due to worldwide vaccination programmes. Some stocks of the virus are kept
in high-security laboratories. If smallpox is deliberately released, it could cause
a public health catastrophe.
• Anthrax is a disease caused by a spore-forming bacterium called Bacillus
anthracis. It is caught by humans after contact with infected animals or infected
animal products. It is has the potential to be used as a biological warfare agent.
22
2 • Challenges confronting agriculture
• Crop diseases, such as smuts and blights caused by fungi, can be spread easily
by fungal spores. If large areas of cereal crops are destroyed, less grain is
produced.
• Ricin is a toxin made from waste left over from processing castor beans. It is
easily made and very toxic. As little as 500 micrograms, about the size of the
head of a pin, injected into a human is lethal. Ricin has been used as a bioterrorist weapon and is a serious threat.
I
Why are smuts and blights a hazard?
Bio-terrorism is hard to protect against or to prevent because small quantities of
the organisms are easy to hide and can be spread quickly. Sometimes pathogenic
organisms can be spread by mistake or by people unaware of the consequences.
The rules which govern the import and export of plants and animals are designed
I to protect against diseases being transported around the world.
Food security
food security ► Food security refers to the availability of food and access to it. As defined by the
FAO, 'food security exists when people have physical and economic access to
sufficient, safe and nutritious food to meet their needs for an active and healthy
life'. The United States Department of Agriculture (USDA) states that food security
for a household means access to enough food for an active, healthy life. It includes
the availability of nutritionally adequate and safe foods and an ability to acquire
these foods in socially acceptable ways (without resorting to emergency food
supplies, scavenging or stealing).
Worldwide, up to 2 billion people lack food security due to:
• poverty
• global population growth
• climate change
• increased production of biofuels on agricultural land
• loss of agricultural land to industry and residential areas.
I
I
What does food security mean to a household?
There are direct relationships between agricultural productivity, hunger and
poverty. 75% of the world's poor live in rural areas and make their living from
agriculture. Hunger and child malnutrition are greater than in urban areas. In
rural areas, there is greater dependence on subsistence farming so improvements
in agricultural productivity aimed at small-scale farmers will benefit the rural poor
first.
Increased agricultural productivity enables farmers to grow more food, which
leads to better diets. Market conditions that offer a level playing field also lead to
higher farm incomes; and raised incomes often result in farmers growing highervalue crops, benefiting themselves and the economy.
Environmental degradation
environmental degradation ► Environmental degradation refers to the environment being damaged in any way.
Environmental degradation is brought about by:
• natural hazards
• atmospheric pollution
• water pollution
• land pollution
• global warming
• coral reef destruction
• deforestation.
23
Section A: The Business of Farming
Natural hazards
natural hazards ►
Natural hazards are hazards which are not man-made. They occur at the surface of
the Earth, causing loss of life, damage to property and land. They can cause shortterm or long-term changes.
The most common natural hazards in the Caribbean are volcanic eruptions,
earthquakes, floods and hurricanes. Some of their effects are shown in Table 2.1.
Natural hazard
Volcanic eruptions
Effect on the environment
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.
Earthquakes
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 which 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; 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 cause wind damage, wave damage, storm surges
in coastal areas and flooding. Crops and trees are damaged
by high winds and storm surges mean that salt water pollutes
inland areas. Sea water is poisonous to plants and livestock
and soil remains contaminated until the salt is removed by
rainwater.
Floods
Hurricanes
Table 2.1
Natural hazards and their effects on the environment.
Atmospheric pollution
atmospheric pollution ►
Explain how acid rain is caused and what effects
it has.
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 for the generation of electricity). Smoke, dust particles and gases
(carbon dioxide, sulphur dioxide, nitrous oxides) 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 ►
What are the consequences of the leakage of
sewage into freshwater?
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 run-off. Organic matter and
nutrients in freshwater can cause algae to grow rapidly and crowd out other water
plants. When the algae die, they are broken down by bacteria which use up oxygen
in the water. The result is that other aquatic organisms die through lack of oxygen.
In marine ecosystems, agricultural run-off can upset the food webs. Oil spillage
kills sea birds and affects plankton on which marine organisms are dependent.
Land pollution
land pollution ►
24
Land pollution can be caused by agricultural activities, urban waste disposal and
mineral extraction. Land that is severely polluted cannot grow crops and poisonous
substances will affect the biodiversity of habitats. Waste from crops and animals
should be composted and recycled for use as fertiliser. Excessive use of fertilisers
and pesticides should be discouraged, so that run-off is minimised.
4
2 - Challenges confronting agriculture
Coral reef destruction
r!
Why might global warming contribute to the
destruction of coral reefs?
Coral reefs are fragile ecosystems and easily damaged by pollution. Polluted water
runs off the land, enters the sea and increases the growth of algae which live on
the reef. This kills the coral underneath the algae.
Corals can be smothered by sediments washed into the sea from rivers and
coastal dredging activities. Over-fishing 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 damage.
If sea temperatures rise, due to global warming, the coral is weakened and
becomes paler in colour. This is called coral bleaching. 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 ecosystem.
Deforestation
deforestation ►
r^
Why should deforestation be controlled?
For thousands of years, forests have been cleared to provide agricultural land
for crop production and rearing animals. The clearance of trees is known as
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 rising
population means that there is pressure to clear land for crop production, industry
and houses. Forests are cleared and wood is used for fuel, but there is no policy for
replanting trees. The forested areas that remain are in mountainous regions with
high rainfall. These 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 the trees bare. Volcanic activity,
producing poisonous gases and hot lava, has affected forests in Montserrat and
St Vincent.
It is important to retain forests as they:
• provide areas for recreation, such as nature reserves and National Parks, with
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.
Within protected areas of forest, replanting and maintenance work can be carried
out to avoid over-exploitation.
Figure 2.7 Deforestation in the
Caribbean.
25
Section A: The Business of Farming
2.3 Terminology used in food safety,
i mportation and certification
Good Agricultural Practices
( GAPS)
►
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
relate to the manufacture and processing of food.
Good Agricultural Practices (GAPs)
As defined by the Food and Agriculture Organisation (FAO) of the United Nations,
GAPs are principles applied to crop production and processing, which result in
safe and healthy food, taking into account economic, social and environmental
sustainability.
GAPs can be applied to a wide range of farming systems and rely on four
principles:
• the economic and efficient production of enough safe and nutritious food
• sustaining natural resources
• maintaining farming enterprises and jobs
• meeting the cultural and social demands of society.
How does the use of heavy machinery destroy the
soil structure?
GAPs provide opportunities to decide which farming practices to follow to achieve
higher production.
Some GAPs relate to soil:
• reduction of erosion by hedging and ditching
• the correct application of fertilisers
• the use of manure, grazing and crop rotation in restoring and maintaining the
organic content of the soil
• green manuring by growing leguminous crops
• protection of soil structure by limiting use of heavy machinery (this compacts
the soil).
Some GAPs relate to water:
• careful use of irrigation
• avoiding drainage and fertiliser run-off
• planting of suitable crops in areas of low rainfall
• maintaining plant cover to avoid water run-off in the wet season.
Some GAPs relate to animal production, health and welfare:
• respect for animals
• avoidance of procedures such as tail docking and de-beaking
• reducing use of antibiotics and hormones unless needed for treatment of
disease
• avoidance of animal waste in any feed given to stock
• reducing the transport of live animals, thus cutting down on the risks of
epidemics
• keeping records so that all animals and their treatments can be traced.
HACCP
26
►
Hazard Analysis Critical Control Point (HACCP)
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.
2 • Challenges confronting agriculture
There are seven HACCP principles:
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 critical control point. A critical limit sets a
value at which a hazard must be controlled at each point.
4. Establish critical control point monitoring requirements to ensure that the
manufacturing process is under control.
•
Establish corrective actions to be taken when the monitoring process indicates
i ^5.
that a critical limit is not being met — this means that products harmful to
What do the initials HACCP stand for
health do not become available for human consumption.
6. Establish record-keeping procedures so that it can be seen that all steps of the
process have been monitored for hazards.
7. Establish procedures for ensuring that the HACCP system is working as it
What is a CCP?
should and that the products from any manufacturing process are safe.
hazard analysis ►
Food processing plants must ensure that their products are safe. They are required
to validate their own HACCP plans, which have to be verified to make sure that
they are adequate. Verification includes reviewing of plans, inspection of critical
control point records and microbial sampling.
Good Manufacturing Practices (GMPs)
GMPs ►
Suggest reasons why there are safety problems
with refrigerated and dairy foods..
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 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 procedures and
deficiencies in training employees. Refrigerated foods, meat and dairy foods 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 training
of employees is important in maintaining 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.
• The major challenge for agriculture is to feed an ever-increasing global
population whilst preserving the natural environment.
• Agriculture is a very important part of the economy of the Caribbean.
• Agricultural productivity is affected by climatic conditions. There is a dry season,
when water is short, and a wet season with hurricanes and high winds.
• In the dry season, soil water needs to be conserved and used more efficiently.
In the wet season, good drainage is important. Pests and diseases of crops are
more abundant in the rainy season.
• Hilly areas are more difficult to farm because of the lack of infrastructure and
problems with the use of heavy machinery and transportation of produce.
• Agriculture in the Caribbean needs to be more mechanised to be more efficient.
• Investment in rural infrastructural development is the key to agricultural
development and food security.
• More trained extension officers are needed to spread information on technical
developments to farmers.
27
Section A: The Business of Farming
Praedial larceny is a problem, especially for farmers who produce fruit and
vegetables which are easily picked and stolen.
• Some farmers own land, but many are landless and rent, lease or enter into a
share-cropping agreement with landlords.
• More stringent government policies are required in the Caribbean to ensure
that good agricultural land is not used for housing.
• Farming has an impact on the environment and there are concerns about the
destruction of ecosystems, loss of biodiversity and pollution.
• Plant, soil and animal material brought into the country illegally by travellers
may contain pests and diseases which could cause havoc to domestic agriculture.
• Natural disasters, such as floods and hurricanes, can damage crops and livestock
in the Caribbean.
• Previously, women were paid lower wages than men and were not appointed to
managerial positions. Nowadays, gender equality is the norm for all occupations.
• World agriculture has been revolutionised by globalisation which has opened
up world trade and financial markets.
• There is worldwide concern that ecosystems are destroyed and biodiversity is
lost as a result of clearing land to increase food production.
• Global warming resulting from an increase in greenhouse gases can speed up
climatic and environmental changes.
• All countries need to be aware of the dangers of bio-terrorism in which microorganisms can cause death or disease to crops and livestock.
• Increased agricultural efficiency means that farmers can grow more food,
leading to better diets and higher•incomes for farmers.
• Environmental degradation, resulting from pollution, deforestation and natural
disasters, affects agriculture. Measures can be taken to minimise these effects
without reducing the efficiency of agriculture.
• Good Agricultural Practices (GAPS) are recommendations by the FAO for the
production of safe and healthy food whilst sustaining natural resources.
• There are strict guidelines for the safe production of processed food, so that the
contamination of raw materials and manufactured food products is prevented.
•
Answers to ITQs
can be conserved by using organic matter as a mulch. Seedlings can
be transplanted into concave areas so soil water is kept around the roots.
;1
IT02
Establishing wind-breaks to protect crops; staking crops so that they have
support; pruning trees so that they have a compact shape.
ITQ3 Farming in mountainous areas is more difficult because the use of heavy
machinery may be restricted, cultivating the land is not easy and the
harvesting of the crops can take longer. Farmers may have to use contour
terracing. The topsoil is shallower and liable to erosion.
ITQ4 Mechanisation of farming is limited because many farms are on hilly
or mountainous terrain so that the use of machinery for cultivation is
difficult. In addition, machines are costly and the poorer farmers cannot
afford them.
ITQ5
The basic facilities required are: roads, a water supply, electricity and
telephones, shopping areas, markets, public transport, schools, medical
centres.
1T06
Extension officers advise farmers on the latest developments in
agriculture and modern technology as it relates to agriculture.
ITQ7 Farmers are not sure that modern ways of doing things will work. The
problem can be overcome by demonstrations of any new techniques at
training centres.
28
2 • Challenges confronting agriculture
1108 Praedial larceny is the theft of agricultural produce, such as crops and
livestock.
ITQ9 The hiring of estate police by farmers' co-operatives; the imposing of
more severe fines; regular police checks in rural areas.
11010 Land tenure is the right to hold or own land.
11011 The management of land resources needs to be improved by increasing
soil fertility, conserving freshwater resources and maintaining biological
diversity.
11012 It is important that pests and diseases are not spread from country
to country when food products are imported or exported. Incoming
plants and animals are quarantined and the export of food products
is controlled. If diseases do spread rapidly then there could be serious
consequences to crop production and the raising of livestock.
11013 Gender equality means that all jobs are open to people with suitable
qualifications, regardless of whether they are male or female.
ITQ14 Women could be discriminated against where heavy manual labour was
involved. Also, women might not be considered for managerial positions
where they were in charge of a number of male employees.
11015 Globalisation opens up access to world markets for farmers' produce and
allows them to learn about new production techniques.
11016 Genetic diversity is the diversity of genes and organisms; species diversity
refers to the populations of organisms in an ecosystem; ecosystem
diversity is the range of habitats on Earth.
11017 Global warming is the increase in temperature of the Earth's atmosphere
due to more heat energy being trapped by carbon dioxide and methane.
11018 Carbon dioxide and methane are called greenhouse gases; as they
increase in the atmosphere, due to the burning of fossil fuels and the
internal combustion engine, they trap more heat energy. Any increase in
these gases will result in a rise in the global temperature.
11019 Smuts and blights are fungal diseases of cereal crops. They are spread
by spores and can cause the failure of a whole crop. They are potential
weapons of bio-terrorists because a small quantity of the fungus can
spread quickly through a crop. The crop can be infected easily without
attracting attention.
11020 Food security means that the household has enough nutritionally
adequate and safe food in order to lead an active, healthy life.
17421 Acid rain is caused by sulphur dioxide in the atmosphere dissolving in
rainwater. It damages crop plants, causes leaves to drop from trees, and
gets into freshwater where it makes ponds and lakes more acid — affecting
fish and other wildlife.
11022 When sewage leaks into freshwater, it causes algae to grow more rapidly.
Their growth deprives other plants of light. When algae die, they are
broken down by bacteria. The bacteria use up oxygen in the water and
other organisms, such as fish, die.
11023 If sea temperatures rise as a result of global warming, the structure of the
coral is weakened. The reef organisms are more susceptible to bacterial
and viral diseases.
ITQ24 Deforestation needs to be controlled so that there are forest areas for
recreational purposes. Also, deforestation causes soil erosion, less oxygen
is produced if the trees are removed and there is less biodiversity.
IT025 Heavy machinery compacts soil, making it difficult to cultivate; this could
contribute to soil erosion if there is heavy rainfall.
29
Section A: The Business of Farming
11026 HACCP stands for Hazard Analysis Critical Control Point.
ITQ27 A CCP is a Critical Control Point. It is a stage in a manufacturing process
at which a hazard can be removed, reduced or prevented.
11028 Refrigerated and dairy foods may be contaminated with bacteria. For food
safety the correct temperature must be maintained. This prevents growth
of bacteria.
Examination-style
questions
Multiple Choice Questions
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 the range of habitats
B the diversity of genes
C the diversity of organisms
D the 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 affect fanning 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 which 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.
..........
AlIEIld1111ES to C0111111110[1d1
idfirl q
By the end of
this chapter
you should be
able to:
3 explain what is meant by 'non-conventional' farming systems
3 describe organic farming and hydroponics
3 discuss urban and pen-urban farming
,/ explain the principles of organic farming
3 state how organic farms are certificated.
Concept map
Non-conventional farming systems
Organic arming
Other systems
I mportance
Trough culture
Certification
—
Hydroponics
-
Grow box
Principles
Management
Soil
Weeds
Urban and periurban farming
Nutrient film
technique
Pests
..-
31
Section A: The Business of Farming
3.1 Non-conventional farming systems
Modern farming methods
conventional farming ►
monoculture ►
Explain what is meant by monoculture.
1r
Why are traditional methods of agriculture more
sustainable than monoculture?
By conventional farming methods we mean modem farming methods, which
are designed to produce large quantities of food to be sold for profit. Farming is
now a large-scale industry and relies on the use of machinery and chemicals. Few
people are required to operate the machinery, which prepares the land, sows the
seeds and harvests the crops. This trend in farming has occurred in response to
increasing populations and the demand for cheaper food.
Monoculture, where large areas of land are planted with the same crop year
after year, is a feature of modem farming. It often leads to greater farm profits as a
much greater quantity of a crop can be grown. However, monoculture also leads
to loss of natural ecosystems and habitats.
Modem farming relies on artificial fertilisers to improve soil fertility and increase
crop yields. Diseases are prevented by pesticides, weeds are destroyed by herbicides
and chemicals are fed to animals to promote growth.
However, there is now concern that modem agricultural practices damage the
environment and soil structure, reduce biodiversity and introduce health hazards
to both humans and animals.
Figure 3.1 An example of monoculture: growing tobacco.
Traditional farming methods
In contrast to modern fanning, traditional methods of agriculture cause less
damage to the environment. An example of traditional fanning is small-scale
mixed farming ► mixed farming, where there is recycling of waste materials. The waste from
animals is used as manure, so nutrients are returned to the soil via the carbon
and nitrogen cycles (see pages 103-106). By growing a wide range of crops and
using crop rotation, both soil structure and fertility can be maintained. Traditional
farming methods are more sustainable than modem methods.
32
3 • Alternatives to conventional farming
Non-conventional farming systems
non-conventional farming
systems ►
Non-conventional farming systems have developed in response to concerns
about the effects of intensive systems on the environment and the quality of food
produced. Most non-conventional systems are labour-intensive (they employ more
people than conventional systems). Also, yields are lower than in conventional
systems. However, the food produced by non-conventional farming is likely to be
of better quality and so command a higher market price.
Organic farming
organic farming ►
Organic farming is a form of non-conventional agriculture that excludes, or
strictly limits, the use of artificial fertilisers, herbicides and pesticides, plant growth
regulators and animal feed additives. Biological pest control is used instead to get
rid of pests. Compost, green manure and crop rotation are used to maintain soil
fertility. Techniques may vary from country to country, but the principles and
practices were set out in a document produced by the International Federation
of Organic Agricultural Movements (IFOAM). In 2005, this organisation created
the Principles of Organic Agriculture as guidelines for the certification of organic
farms.
Principles of organic farming
The list below shows what organic farmers are aiming to achieve.
• Produce good food that has a high nutritional value.
• Maintain and improve soil fertility.
• Use renewable resources wherever possible.
• Protect wildlife habitats.
• Avoid pollution from agricultural techniques.
• Encourage a diversity of wildlife on the farm.
• Raise livestock in conditions which allow them to carry out innate
(natural) behaviour.
Practical activity:
Visit a local organic farm. Find
out how the organic farm differs
from a conventional farm in terms
of crops and livestock, use of
fertilisers and pesticides, and feed
given to livestock.
Organic farmers need to develop a fertile soil on which they grow a mixture of
crops. They cannot use artificial fertilisers and use of pesticides is restricted. They
rear animals in a humane way, without routine use of the hormones and antibiotics
that are common in intensive livestock production. They are not allowed to grow
genetically modified crops.
List the main principles of organic farming.
Hydroponics
hydroponics ►
nutrient film technique (NFT)
►
Hydroponics (from the Greek words hydros [water] and ponos [labour]) is the
practice of growing plants in a nutrient solution without soil. This is another form
of non-conventional farming. Instead of soil, the plants may be rooted in peat,
sand or rock wool. Soil is not essential for the growth of terrestrial plants (plants
that grow on land), as roots can absorb all the mineral ions needed for growth
from a nutrient solution.
Hydroponics can supply fruit and vegetables in areas where the soil is lacking or
of poor quality. The commercial use of hydroponics was demonstrated on Wake
Island in the Pacific. In the 1930s, this rocky atoll was a refuelling stop for an
airline. As there was no soil, vegetables for the passengers were grown in nutrient
solutions. Space research programmes have also looked into growing plants on
other planets or during long flights.
The nutrient film technique
In the 1960s, the nutrient film technique (NFT) was developed. A circulating
system supplies plant roots with oxygen and nutrients. This technique is widely
used for growing tomatoes, cucumbers and salad vegetables in glasshouses.
33
Section A: The Business of Farming
The plants are grown in troughs, with roots embedded in rock wool or some
other inert material. They are supplied with a nutrient solution containing the
balance of minerals essential for healthy growth. The solution is pumped into the
troughs, circulates around the roots, collects in a tank and is then re-circulated.
Figure 3.2 The nutrient film technique.
O
Concentration of the nutrient solution can be varied at different stages of growth
as required. The solution is aerated so that roots obtain oxygen. As plants grout,
they are supported by wires suspended from the roof of the glasshouse.
What do the initials NFT stand for?
0
Name THREE crops that can be grown using
hydroponics.
=
3
Practical activity:
If possible, visit a farm where
hydroponics is used to grow a
crop.
grow box ►
Practical activity:
Explain how you would grow a
salad crop using a grow box or
a trough. Include as much detail
about the conditions needed as
possible.
Describe the advantages of grow boxes and
trough culture,
34
The advantages of the nutrient film technique are:
• high yields as plants get all the nutrients they require
• soil-borne diseases are eliminated
• produce is clean and not covered in soil
• harvesting the produce is easier and more efficient.
The nutrient film technique is usually carried out in glasshouses, where
temperature and light can be controlled. Costs of installing and running this are
high, but producing fruit and vegetables in large quantities and of good quality out
of season can make this technique profitable.
Grow boxes
A grow box is an enclosed box used to grow plants in a self-contained environment.
The box has a hydroponics system, a built-in light and a means of ventilation.
Some have air-conditioning to maintain the correct temperature and to enrich the
atmosphere with carbon dioxide to boost growth (carbon dioxide makes plants
grow faster).
Grow boxes are used by people who have no garden and for growing plants out
of season. They are easy to use and allow the gardener to control the environment
of the plant to achieve the best growth. They are also used for growing plants in
controlled conditions in laboratories.
Simplified grow boxes, suitable for patios and decking, have been devised. These
incorporate a watering system and deliver measured quantities of fertiliser, but they
are designed for use outdoors and do not include a lighting system or temperature
control.
In the Caribbean, grow boxes of varying sizes are constructed using local and
discarded materials such as bamboo, wood, galvanised sheets and bricks. The
growing medium may be a mixture of topsoil and pen manure, sharp sand and
rotted bagasse (or plastering sand and rotted sawdust).
3 • Alternatives to conventional farming
Trough culture
trough culture ► Trough culture involves growing crops in shallow troughs, 15-20 cm deep and
60-70 cm wide. Troughs can be filled with an inert, soil-less medium, such as rock
wool, and are connected to a drip system which 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; the gardener can put them
in greenhouses or anywhere convenient.
Both grow boxes and trough culture enable plants to be grown where space is
limited or soil is poor. Modifications can be made to suit circumstances, e.g. the
number of units and their arrangement; the use of different types of inert material;
whether temperature and lighting need to be controlled. Commercial systems
have many units, but both methods can be used on a smaller scale.
Figure 3.3
Trough culture.
market gardens ►
Explain why it is more profitable for a small
farmer to sell his produce directly to the
consumer (rather than selling it to a wholesaler).
Urban and peri-urban farming
Urban and peri-urban farming is the cultivation of small areas of land, usually less
than 2 hectares, in or near cities, towns and 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. They contribute to food safety and food security.
Market gardens are intensively cultivated and most crops grown are shortterm, growing and ripening within 3 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, then farmyard
manure is used together with artificial fertilisers. This type of farming includes the
use of pots, troughs, grow boxes, discarded tyres, hydroponics and sheds covered
with polythene.
Produce is harvested by the farmer, often with the help of his family, who also get
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,
e.g. 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 them to the public.
The benefits of urban farms include:
• a reduction in transport costs as food is grown locally
• fewer pesticides, which make food production more sustainable
• no food preservatives as food does not have to travel long distances
• employment for local people.
3.2 The principles of organic farming
In organic farming, the use of herbicides and pesticides is limited resulting in an
increase in biodiversity. Organic farming benefits the environment in many ways.
Weed species growing in an organic crop attract insects which feed on plant pests.
In turn, these insects will provide food for birds and mammals. The use of farmyard
manure to add organic matter to the soil encourages soil micro-organisms, which
contribute to soil fertility by breaking down plant and animal remains. Overall,
there are 30% more species found on organic farms than on conventional farms.
Organically grown produce is usually higher priced than other produce — but
health concious people will often pay these prices.
35
Section A: The Business of Farming
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 3.1.
Method
Crop rotation ►
Green manuring ►
Intereropping ►
Organic manure and
composts such as
crop residues (sugar
cane waste, spent
mushroom compost)
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 3.4)
• the ploughing in of a cover crop, such
as a legume
• the ploughing in of a crop residue,
such as 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 3.5)
• crops may mature and be harvested at
different times
• 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 run-off during the wet
season
• a second crop can reduce competition from weeds
• if a legume is included then nitrogen fixation is
encouraged
• the cover of vegetation reduces run-off in the wet
season
• saves on space if more than one crop is grown on the
same piece of land
• introduces organic matter which binds soil particles
together
• helps 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 3.1 Methods of managing soil fertility on organic farms.
Why is crop rotation good for soil fertility?
How does intercropping benefit the small farmer?
Area I
Area 2
Area 3
Area 4
Leaves
Fruits
Roots
Legumes
Legumes
Leaves
Fruits
Roots
Roots
Legumes
Leaves
Fruits
Fruits
Roots
Legumes
Leaves
Year
I
Year
2
Year
3
Year
Figure 3.4 A four-year crop rotation.
36
Figure 3.5 Intereropping: ackees and pasture.
3 Alternatives to conventional farming
Weed control on organic farms
weed control ►
List FOUR ways of controlling weeds without
using a weedkiller (herbicide).
Weed control on organic farms poses problems as herbicides are not encouraged.
Methods include hand-weeding, hoeing, mulching with compost and the use of
plastic films 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
The control of insects and other pests is difficult to achieve without chemicals.
Pests cause serious losses and few organic farmers manage to eliminate the use
of chemical pesticides entirely. Organic insecticides include Bt (a bacterial toxin
produced by Bacillus thuringiensis), Pyrethrum and Rotenone. Although these
are permitted, they are often combined with biological pest control and cultural
integrated pest management methods in a technique called integrated pest management (IPM). IPM involves
( IP M) ► pest control using an array of complementary approaches including natural
predators, pesticides, and other biological and environmental control practices. In
this way, the use of chemicals is reduced and damage to the environment and
harmful residues in food are minimised.
biological pest control ►
Biological pest control involves the introduction of another species to control the
pest. The introduced species will reduce the population of the pest, but will not get
rid of it 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.
What are the drawbacks of biological pest
control?
Before any biological control method is used, it has to be tested to make sure
that no unwanted diseases are introduced, that it only affects the pest organism,
and that the control organism can be bred in sufficient numbers to be effective.
Biological control is most successful in glasshouse crops, such as tomatoes and
cucumbers. The control organisms are introduced into the glasshouse (an enclosed
area), and numbers of pest and predator can be carefully monitored.
If the life cycle of an insect pest is interrupted, its numbers will fall. Insects mate
once and the female stores the sperm. If the sperm are infertile, 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 do not develop. This method has been effective in
the control of screw-worms which harmed the cattle industry in the USA.
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 for the females to mate with,
no eggs will be laid and the pests will be reduced.
Practical activities:
1. List insects 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.
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.
37
Section A: The Business of Farming
Certification of organic farms
Farmers who sell their produce as 'organic' must obtain certification.
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)
• the farm has to be inspected by the agency
• the farmer will be notified whether or not the application is successful.
The application form requires details of:
• soil fertility planning
• seeds and seed planting
• weed and pest management practices
• storage and handling of produce
• details of the crops grown and the fields used (a map of the farm has to be
supplied)
• plans for monitoring how the farm will be managed to avoid contamination
with non-organic products.
List FOUR things that an inspector would check
on a visit to certify an organic farm,
When the farm is inspected, the fields, implements and buildings are reviewed.
The farmer provides the inspector with records of crops planted, sources of seeds
used, details of harvesting and storage, how the produce is transported to market,
and the sales records. Before a certificate can be granted, land has to be free
from prohibited pesticides and fertilisers for 3 years. If livestock are involved, the
conditions in which they are kept, their feed and 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 much recordkeeping and paper-work. 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.
Summary
• Conventional farming is designed to produce large quantities of food cheaply.
It is' mechanised to minimise labour costs.
Artificial fertilisers and pesticides maintain soil fertility and control pests.
Large areas of land are cultivated and sown with one crop (monoculture).
The environment is affected, reducing biodiversity.
• Organic farming limits the use of artificial fertilisers, herbicides and pesticides.
The environment is protected and there is an increase in biodiversity.
Soil fertility is maintained by using compost, green manuring and rotation of
crops.
Pest control is achieved by means of biological controls.
• Hydroponics is a system of growing crops without soil.
The crops are provided with the nutrients they need in solution.
Crops grown in this way are easy to grow, harvest and clean.
• Grow boxes and trough culture can be used where space is limited.
• Urban and peni-urban farming make use of land in and around towns and
cities.
Crops can be marketed in towns and cities and form an important resource.
38
3 • Alternatives to conventional farming
•
•
Answers to ITQs
The principles of organic farming are to maintain ecological balance and
biodiversity, manage soil fertility and control pests and weeds without the use
of harmful chemicals.
To qualify for organic status, a farm must be inspected and certified.
ITCH
Monoculture involves the cultivation of large areas of land which are
then planted with one crop. It gets rid of small fields and means that
machinery can be used for cultivation, saving on the cost of labour.
11112
Traditional methods of agriculture, such as small-scale mixed farming,
mean that animal waste can be recycled and used on the fields. Nutrients
are returned to the soil by means of the carbon and nitrogen cycles. Soil
structure and soil fertility are maintained.
ITQ3 To produce good food with a high nutritional value; to maintain and
improve soil fertility; to use renewable resources; to protect plant and
wildlife habitats; to avoid pollution; to raise livestock in a humane way.
ITQ4 NFT stands for nutrient film technique.
11115
Tomatoes, lettuce, cucumbers.
IT06
Grow boxes and trough culture enable crops to be grown where space is
limited. Grow boxes fitted with lights can be used to grow plants indoors
or in laboratories. They are useful if the soil is of poor quality. Crops can
also be grown out of season.
ITQ7 The small farmer would not get as much for his crops if he sold them
to a wholesaler. He would have to pay for their transport and then the
wholesaler would need to make a profit as well. The small farmer will
make more money by selling the crops from a roadside stall run by a
member of his family.
ITQ8
Crop rotation improves soil texture, it breaks the life cycles of pests and
diseases and it increases the nitrogen content of the soil if a legume is
included.
11119
Two or more crops can be grown at the same time, which saves space;
crops can be harvested at different times; it increases the ground cover
and prevents run-off; reduces competition from weeds.
111110 Hand-weeding; hoeing; mulching with compost; the use of plastic films.
IT1111 Not all pests will have a natural predator; the predator has to be bred and
released in sufficient numbers to be effective; the method must be tested
thoroughly to make sure there are no diseases introduced; it is difficult to
control unless it is introduced into an enclosed area.
ITC112 Sources of seeds; details of how crop is stored; use of compost; how crop
is harvested; how crops are transported; care of animals; records of how
animals are fed and treated.
39
Section A: The Business of Farming
Examination-style
questions
Multiple Choice Questions
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 infertile
B make them unattractive to the females
C attract the females to them
D kill their sperm
Short answer and essay-type questions
5. (a) Explain why conventional farming has developed into a large-scale
industry.
(b) Describe how non-conventional farming methods differ from
conventional ones.
6. (a) What are the benefits of growing crops using the nutrient film
technique?
(b) Why do temperature and light need to be controlled in such
systems?
7. (a) What is a pen-urban farm?
(b) Why is it beneficial to the community?
8. Describe the ways in which soil management can maintain soil fertility
on an organic farm.
9. Describe the procedure by which a farm can become certified as an
organic farm.
40
.................
uuw
EC011011iC factors of
VodEt1011
By the end of
this chapter
you should be
able to:
explain the economic functions of production, consumption and marketing
list the factors that affect production
describe how the factors of production are related to agriculture
state what is meant by the law of diminishing returns
3 show how demand and supply is related to pricing.
3
Concept map
Factors of production
Agricultu al production
Consumption
tenure
Land
Supply and
demand
suitability
family labour
Pricing
Labour
hired
commercial banks
Law of diminishing
returns
Source
agricultural banks
total product
co-operatives
Capital
average product
credit unions
marginal product
fixed capital
Types
marginal cost
working capital
Management
41
Cen•i-- A. TL_
Section A: The Business of Farming
4.1 The economic functions of production,
consumption and marketing
mixed farm ►
agricultural enterprise ►
i
Name the THREE major economic functions in any
country.
Farming is a business and a farm can be
defined as an economic unit engaged in
marketing
(driver)
the production and sale of agricultural
produce for maximum profit. A farm may
produce crops or livestock. Sometimes
farms produce both crops and livestock
the economy:
(a mixed farm).
vehicle of change and
development
Farms often consist of different sections,
each focused on the production of one
production
consumption
type of crop or livestock. Each section
(engine)
(fuel)
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. Figure 4.1 Economic functions.
To do this, knowledge of the production
process is necessary. The farmer also must understand the likely demand for the
commodity and the way in which it is marketed.
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.
Production plays the role of the engine of the economy, marketing has the role
of the driver, and consumption provides the fuel (see Figure 4.1).
Production
production ► Production is a planned economic activity incorporating several inputs; it focuses
on the manufacture of goods and the provision of a number of services. The aim of
production is to satisfy people's wants (see Figure 4.2). As the volume of production
increases, wealth is created and this promotes economic welfare of the population.
Their standard of living is improved as more of their wants are satisfied.
PRODUCTION
• a process
• an economic activity
Consists of:
• primary production
• secondary production
FOCUS
SERVICES
I COMMODITIES/GOODS
• commercial, e.g. agri-chemicals
• technical, e.g. extension officer
• professional, e.g. veterinarian
• capital goods, e.g. farm tractor
• consumable goods, e.g. foodstuffs
• luxury goods, e.g. big screen TV
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 4.2 The concept of production.
42
4 Economic factors of production
Types of production
primary production ►
primary products ►
secondary production ►
secondary products ►
There are two types of production: primary and secondary. Primary production
refers to goods or raw materials which are produced initially, for example pineapple
or sugar cane. Some of these goods may be consumed as primary products.
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, or sugar cane can be processed to
make sugar, molasses, bagasse and rum.
Goods
capital goods ►
luxury goods ►
consumable goods ►
Different kinds of goods are derived from production. Capital goods are items such
as a farm tractor and a dairy herd — these are used in several production cycles.
There is always a quantity of goods existing on a farm and this is called the capital.
Luxury goods, such as a swimming pool and a big screen television set, provide
enjoyment and act as status symbols. Consumable goods, such as foodstuffs, are
goods which are essential for human nutrition.
Services
Services can be grouped into:
What are the objectives of production?
Giving appropriate examples, explain the
difference between primary production and
secondary production.
• 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.
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
which keeps the economic engine of production running (see Figure 4.3).
• income level of consumers
• satisfaction of consumer needs
• product substitutes (are there
• an economic consumer-centred
other products that could be
used instead?)
FACTORS INFLUENCING
CONSUMPTION
DECISION-MAKING
• religious reasons
• health concerns
• aesthetic features
1-■
• customers
• clients
CONSUMERS
• end users of
the product
activity and process
• an activity that fuels the engine of
1-■
production
CONSUMPTION: WHAT IS IT?
• the purchase and utilisation of
goods and services
• the end product of production
and marketing
(what the product looks like)
Figure 4.3 The concept of consumption.
Consumption patterns vary. Some factors which contribute to decision-making by
consumers are:
• Income level
Consumers want to obtain goods and services at the lowest cost. They
purchase and use those goods and services which they can afford. People on
low incomes are limited in terms of the quantity and the form of product
which they can purchase.
• Satisfaction of needs
Consumers choose goods and services which satisfy their tastes and
convenience. With respect to food, consumers buy products which are easy to
prepare and use, and which meet their survival, nutritional and health needs.
43
Section A: The Business of Farming
Explain the meaning of consumption.
t
^
State FOUR factors which contribute to
consumption decision-making by consumers,
• Religious reasons
Some consumers do not buy ce rt ain foods, such as pork and beef, due to
religious beliefs. Others buy only 'halal' meat from reputable meat shops.
' Halal' involves the reciting of a special prayer by Muslims as the animal is
being slaughtered.
• Health concerns
More consumers are becoming health-conscious and avoid buying foods
which contain high amounts of cholesterol and saturated fats.
• Aesthetic features
Product features (design, presentation, colour, taste and general appearance)
appeal to consumers, increasing 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.
Marketing
marketing ► Marketing is the link between production and consumption. It incorporates several
business activities in a co-ordinated way to promote the flow of goods and se rv ices
from the point of production until they finally reach the consumer. The process is
streamlined to get the ri ght product to a particular consumer at the ri ght place and
time. This is achieved by the co-operative effort of each business operator in the
marketing channel.
Middlemen operate between the producers and consumers. They are agents,
middlemen ►
brokers, wholesalers (merchants), processors and retailers (vendors).
The merchant wholesalers purchase and collect products together at a focal point
for dist ri bution to processors and retailers. Often this is accomplished through the
services of commission agents and brokers, who are also acting as salespersons.
Huge sums of money are spent in advertising and product promotion to persuade
consumers to purchase and use new products.
Marketing functions (see Table 4.1) vary in complexity, depending on the nature
of the products, quantity produced and the characte ri stics of the market.
Main function
Includes
Activities involved
Merchandising
• buying
• pricing
• selling
The focus is on trading, product
promotion, transfer of title and the
ownership of goods.
Handling
•
•
•
•
transportation
grading
assembling
storage
Attention is paid to the physical
activities which enable processing
and easy distribution to retailers and
consumers.
Processing
•
•
•
manufacturing
packaging
labelling
These activities change the form of
the product, add value and increase
the shelf-life. In addition, they seek
to satisfy consumers' tastes and
preferences.
Supporting
• standardisation
• financing
• risk-bearing
(insurance)
• market intelligence
r,
Name the FOUR main groups of marketing
functions and explain why each is involved in the
marketing process.
These activities are regarded as
'facilitating functions', which means
that they enable all the other functions
to be carried out smoothly.
Explain the role of middlemen in the marketing
process.
Table 4.1 Marketing functions.
4.2 The factors of production
Capital is needed to finance any manufacturing process, labour to carry out the
tasks, and some management structure is necessary to co-ordinate the activities.
44
4 Economic factors of production
factors of production ►
The essential resource is the one from which the product is derived. In the case
of agricultural production, land is an essential resource (see Figure 4.4).
Agricultural production varies with the amount, quality and effective use of
these essential resources: land, labour, capital and management. These resources
are known as the factors of production.
4.3 The factors of production related to
agriculture
land.)
FACTORS OF
PRODUCTION
Land
manageme nt
Figure 4.4 The factors of production.
sharecropping ►
The Caribbean region is dominated by small island states with little flat or
undulating land and there are numerous smallholdings on hilly terrain. Only
Guyana and Belize have large expanses of flat land suitable for large-scale
agricultural development. Unfortunately, those areas are currently under-used.
Despite land reclamation initiatives in some Caribbean countries, land as a factor
of production is a limited resource which cannot be created.
Farmers may work on land which is rented or leased. Many do not own land
and enter into sharecropping arrangements with their landlords. Sharecropping is
a system of agriculture or 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. Often
sharecropping farmers may farm two or more scattered holdings. Land tenure
systems were described in Chapter 2.
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; whereas the topography affects the
ease of cultivation and equipment that can be used (see Chapter 2).
Loss of agricultural land
rros
List FOUR characteristic features of land as an
agricultural resource in the Caribbean.
Describe TWO major causes of the loss of prime
agricultural land both locally and regionally.
Land often appreciates (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 mean that less agricultural land
is 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, cultural practices and take advantage of improved
technology. In this way, soil fertility and agricultural land can be maintained.
Labour
labour ► Labour is the total sum of money (the cost) and the total number of man-hours
family labour ►
required for the production of commodities.
In the Caribbean, labour has been a challenging factor of production in
commercial farming, both locally and regionally. Slavery and indentureship,
instituted by the former plantocracy, have resulted in a negative attitude towards
agriculture labour. III-treatment of the slaves resulted in their descendants pursuing
other careers rather than working on the land.
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 applications
or pest and disease control
45
Section A: The Business of Farming
• task labour for specified hours of work and operations such as procuring
forage and milking cows
• contract labour for infrastructural works, such as the construction of livestock
pens and land preparation.
r
i
From an economic standpoint, how is labour
normally measured?
What effect does self-labour and family labour
have on the farm profits of small farmers?
1
In Trinidad and Tobago, the minimum wage policy of the government has
increased the income of farm workers, but has not resulted in attracting workers
into the private agricultural sector. People would rather work for the government
unemployment relief programmes where hours of work and tasks are less
demanding. The wages and conditions are also better.
The intervention of local and regional governments, as well as the International
Labour Organisation (ILO), is required to:
• develop a system of wages based on specialised agricultural skills which would
attract workers to the agricultural sector
• institute measures to foster better labour relations
• promote the welfare of farm workers and their families, especially in the
private agricultural sector.
Capital
capital ► Capital refers to all buildings, machinery, equipment, tools, materials, tree crops
and livestock which are used to produce agricultural goods and services on a
continuing basis.
Each resource has a productive lifespan and a monetary value that decreases
depreciation ► with time due to depreciation. Depreciation is a decrease in value due to 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
assets ► 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 may seek 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.
It is easier for farmers with large farms to borrow money than it is for farmers
with small farms. The larger the farm, the greater the assets; this means that profits
will be greater and the farmer can repay the loan more quickly.
Loans can be obtained from:
• commercial banks
• agricultural banks
• co-operatives
• credit unions.
commercial banks ► Some commercial banks have agricultural advisers who understand the problems
of farming and can give advice. Usually, these banks only make loans to big farms.
Commercial banks do not like lending to small farmers, particularly as their profits
can be badly affected by a bad harvest, hurricanes and other disasters. The small
farmer is not a good risk and may not be able to repay the loan promptly.
The Caribbean Development Bank (CDB) is committed to financing projects in
the region and has departments that loan money to farmers. It prefers long-term
loans and is prepared to allow a longer repayment time.
co-operatives ►
In the case of co-operatives (see page 72), several farmers working together can
apply for a loan. A bank is likely to look more favourably at such applications.
credit union ► A credit union is a co-operative financial institution that is owned and controlled
by its members. It is different from a conventional bank in that members who have
accounts in the credit union collectively own the credit union. It offers facilities for.
savings accounts, as well as for borrowing money at reasonable rates of interest.
46
4 - Economic factors of production
The Caribbean Confederation of Credit Unions is an organisation that fosters
co-operation and mutual self-help. Funds help a variety of projects including rural
development. There is provision for funding small businesses and small farmers.
Jamaica, for example, has 56 credit unions with assets of millions of dollars.
Fixed and working capital
fixed capital ►
working capital ►
Describe FOUR different forms of capital
resources which are essential to a farmer.
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,
cost 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 the receipts for the produce that is sold. He can then see whether
or not there is a profit, which can be invested to improve the enterprise.
Management
What is meant by depreciation?
What is the objective or focus of farm
management?
111115
List FIVE managerial functions on a farm.
Management focuses on the effective use of resources by the farmer. These
resources include land, labour, materials, finances and time. The farmer needs to
achieve maximum production at minimum cost. If used wisely, management can
sustain agricultural output and quality.
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 day-to-day operations on the farm.
Management involves situational analysis, decision-making and the acceptance
of full responsibility for the outcomes, whether they are positive or negative. It
requires people who have gained technical knowledge of the scientific principles of
agriculture, and who can combine practical farming skills with business experience.
A good farm manager has a grasp of the factors of production and uses resources
effectively to make a profit.
4.4 The 'law of diminishing returns'
marginal return ►
The 'law of diminishing returns' states that if inputs are fixed and increasing
amounts of just one variable input are added, then the marginal output per unit
of the variable input will increase up to a certain point and then decline. Another
name for marginal output is marginal return.
To understand how this law works, we need to understand the terms used.
Input
input ►
fixed inputs ►
Input is something that is 'put into' a production system for a particular purpose
and which contributes to the end result. Inputs include energy, information, data
programmes and supplies.
In a farming enterprise, inputs consist of:
• land
• labour
• machinery
• fuel
• farm buildings
• planting materials
• fertilisers and pesticides.
In agricultural production, inputs such as land, machinery, equipment and farm
buildings do not change and are referred to as fixed inputs. The quantities of other
47
Section A: The Business of Farming
inputs, such as labour, fuel, stock and maintenance of equipment may change;
variable inputs ► these are referred to as variable inputs.
Costs
costs ►
r ,
Explain the meaning of inputs' in relation to
farming.
fixed costs, variable costs ►
r
Group the following inputs into fixed inputs and
variable inputs: land, fertilisers, pesticides, seeds,
tractor, fuel, buildings, labour and equipment.
Costs are the expenses involved in any
transaction. Farmers have to buy farm
inputs and convert them into products.
Costs that do not change, such as land
rental, machinery and buildings, are
referred to as fixed costs. Variable costs
are those costs which change with the
level of production. These include the
cost of fuel, feed, fertilisers and pesticides.
Obviously, if a farmer decides to increase
the number of broiler chicks, then more
feed will be needed (see Table 4.2).
Inputs : Broiler Production
Fixed
Variable
Broiler chicks
Land
Buildings
Feed
Equipment
Medication
Pick-up
truck
Labour
Fuel
Maintenance:
machinery and
equipment
Table 4.2 Fixed and variable costs in
broiler production.
Output
output ►
yield ►
r :
Explain the meaning of output.
Using Table 4.3, show how the total cost, the
average cost and the marginal cost for 4 units of
output have been calculated.
The output is the quantity of product resulting from 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 simply numbers of products such as
lettuce or eggs. In economics, output is always measured in units. One unit could
be 100 kg of sweet potatoes or 1000 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.
The costs associated with output are:
• fixed costs (FC)
• variable costs (VC)
• total cost (TC)
• average cost (AC)
• marginal cost (MC).
Units of
Output
Fixed Cost
(FC)
$
Variable
Cost (VC)
$
Total Cost
(TC)
$
Average
Cost (AC)
$
Marginal
Cost ( MC)
$
1
30
70
100
1 00
100
2
30
160
190
95
90
3
30
240
270
90
80
4
30
310
340
85
70
5
30
370
400
80
60
6
30
426
456
76
56
7
30
474
504
72
48
8
30
514
544
68
40
9
30
537
567
63
23
10
30
57 0
600
60
33
Table 4.3 Output:cost relationships.
As can be seen in Table 4.3, at any level of output:
total cost ► • total cost (TC) is fixed cost (FC) plus variable cost (VC)
average cost ► • average cost (AC) is total cost (TC) divided by the number of units of output
marginal cost ► • marginal cost (MC) is the increase in total cost (TC) which is derived from the
last unit of commodity that is produced.
48
4 • Economic factors of production
Returns
Farmers put their inputs into agricultural enterprises with the aim of making a
profit. The yields of the crop or the profits made are called the returns. If a particular
input is increased, unit by unit, there is an incremental increase in output up to a
point. After this point, any further increase in input does not increase the rate of
output. The rate of increase of output declines with each additional unit of input
(see page 47 for the 'law of diminishing returns').
For example, in producing one ha of sweet potatoes, a farmer may gradually
increase the units of fertiliser (input) and find that his yield (output) has also
increased progressively up to a maximum point. After this point, continued
increase in the units of fertiliser results in a steady decline in output. These features
are referred to as increasing returns when the output increases; and diminishing
returns as the output declines. Table 4.4 demonstrates this principle. Figure 4.5
shows the data in Table 4.4 plotted on a graph.
returns ►
increasing returns, diminishing
returns ►
400
5
0
Unit of
input
(Fertiliser)
1
300
0
.s
0
200
10
0
0 100
0
1
2
3
4
5
6
7
Units of input (fertiliser)
Figure 4.5
A graph showing how
an increase in output varies with an
increase in input.
marginal output, marginal return,
marginal product, marginal yield ►
Explain the meaning of marginal return and
diminishing return.
I—
.
.
Fixed input
Increase in
output in kg
2
1250
250
3
1650
300
4
2000
350
5
2275
275
6
2425
150
2525
100
Table 4.4 The effect of increasing input on output.
Increasing returns mean that each additional unit of input increases total outputs
successively. The successive increase in total output for each additional unit of
input is called marginal output, marginal return, marginal product or marginal
yield (these all mean the same).
Decreasing returns mean that each additional unit of input increases total output
at a declining rate. This declining rate of increase in total output, resulting from
each successive unit of input, is called a diminishing return.
The 'law of diminishing returns' is also known as the 'law of diminishing
marginal returns' and also as the 'law of marginal proportions'.
Total output
Corn (100 kg/unit)
Marginal output
Corn (100 kg/unit)
Average output
Corn (100 kg/unit)
1
1
1
Variable input
Fertiliser
(10 kg/unit)
1
2
3
7
13
4
6
3.0
3.5
4.3
1
1
1
1
1
1
1
1
1
4
5
6
7
8
9
10
11
12
20
25
28
30
31
31
30
27
22
7
5
3
2
1
0
-1
-3
-5
5.0
5.0
4.7
4.3
3.9
3.4
3.0
2.5
1.8
Land (1 ha)
Table 4.5
8
Output of
sweet potatoes
in kg
I wo
Remarks
Max MP
MP = AP
Max TP
MP = zero
Negative MP
The effect of fertiliser input on a corn crop. TP = tota product, MP = marginal product and AP = average product.
49
Section A: The Business of Farming
rr
State the law of diminishing returns.
1
rr
In the example in Table 4.5, how many units of
fertiliser should the farmer apply in order to gain
the maximum marginal output from his corn
In Table 4.5, the fixed input is the land, the va ri able input is the quantity of fe rt iliser,
and the output or product is corn. Total output is total yield or total product.
Average output (average yield or average product) is calculated by dividing total
output by the number of units of fe rt iliser applied at any level of production.
Marginal output (marginal yield or marginal product) is the increase in total
output which results from increasing the variable input by one unit. For example,
if 6 units of fe rt iliser are applied, total output is 2800 kg of corn, average output is
470 kg of corn and the marginal output is 300 kg of corn.
I
The total product curve
crop?
total product curve ►
Figure 4.6 shows the relationship between the variable input and the total output.
This is called the total product cu rv e. It rises sharply and then levels off before
declining. The output increases first at an increasing rate, then at a decreasing rate
to a maximum level and then declines. The maximum rate is reached at D, where
the marginal product cu rv e reaches 0. The declining rate of increase starts at A
where the marginal product is at its maximum.
Average product curve
average product curve ► The average product cu rv e is obtained from the total product divided by the number
of units of variable input, so the shape of the curve depends on the shape of the
total product cu rv e. The maximum is reached at C where the average product is
equal to the marginal product.
Marginal product curve
marginal product curve ►
arc
___
The marginal product curve increases very sharply in the beginning, reaches a
maximum and then declines. When the average product is at a maximum (C),
then the marginal product is equal to the average product. The marginal product
becomes 0 (E) when the total product cu rv e is at the maximum (D).
Describe the shape of the marginal product curve.
stage 2
stage 1
;
^
I
I
I
I
^
I
I
I
I
I
I
I
I
I
I
stage 3
D
total product curve
m
0
0
U
a
0
O
B
I
I
I
^ C
I
average product cu rv e
E
0
INPUT: fertiliser (kg)
marginal product curve
Figure 4.6 Diminishing returns: total, marginal and average product.
The three stages
Look at Figure 4.6. In Stage 1, the total product is increasing sharply and the
point is reached 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 decreasing rate. Stage 3 represents the inefficient stage of
production as 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.
Relevance and application
The 'law of diminishing returns' is of relevance to farmers and ho rt iculturalists.
Producers need to remember that there is increasing growth and development in
crops and animals up to a maximum point, beyond which diminishing returns
set in. In producing broilers, for example, diminishing returns become evident
50
,
4 • Economic factors of production
after 8 weeks when they have reached an average weight of 2 kg. From this time
onwards, the birds consume an enormous quantity of feed but the rate of increase
in their body weight declines. Therefore feed is wasted if they 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. Such
resources could be used more profitably to produce other short-term crops or to
raise a new batch of early maturing animals.
Explain why Stage 3 is described as the
inefficient stage of production.
4.5 Demand, supply and price relationships
Sellers mark their goods at a specific price or price range to dispose of their stock. In
this way, they hope to make a profit, enabling them to continue their business and
perhaps expand it. If the price of the goods 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 goods to the place of
business.
The willingness of the consumer to buy goods depends on the price as well as
the supply. If the price is too high, sales are poor because of low demand. If the
What factors are considered by sellers when
price is too low, demand will be high. The seller will be able to sell all his goods, but
fixing the price of a commodity?
his profit may be very small and this could affect his business. Obviously, for any
commodity, there is an optimum price which consumers will be willing to pay and
at which the seller may sell all his goods.
This optimum price requires decision-making on the part of the seller. The
State TWO economic factors which affect the
decision is based on the strength of demand from prospective buyers and a
willingness of consumers to purchase a particular
product.
guarantee of a regular supply of goods.
1
Demand
demand ► Demand is the quantity of a product which consumers are willing to buy at a
certain price at a particular time. Demand is directly related to price. If the price is
high, demand will be low. Lowering the price will result in an increase in demand
for the product.
The demand schedule
demand schedule ►
demand prices ►
The demand schedule for a product is the sum of all the individual consumers'
demands, tabulated to show the relationship between 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.
The information in Table 4.6 can be shown graphically (see Figure 4.7).
Price per kg
($)
Quantity
of cabbage
demanded in kg
3.00
1500
5
4.00
1200
4
4.50
800
5.00
600
5.50
400
6.00
300
6.50
200
Table 4.6 A market demand
schedule for cabbage.
7
6
3
2
1
0
1
I
200
300
[
400
600
800
1200
1500
Quantity of cabbage purchased (kg)
Figure 4.7 A demand curve for the cabbage data shown in Table 4.6.
51
Section A: The Business of Farming
In Figure 4.8, the curve DD shows at a glance the relationship between price and
the quantity bought. It is not necessary to have actual prices and quantities marked
on the axes. You can see that prices and quantity increase evenly from 0 to Y and
demand curve ► from 0 to X respectively and that the typical demand curve DD slopes downward
from left to right.
Y
U
a
0
X
Quantity
Figure 4.8 A typical demand curve.
The `law of demand'
'law of demand' ►
The first law of supply and demand is also called the 'law of demand'. It states that
the lower the price, the greater the quantity that will be demanded.
Change in demand
In Figure 4.9, the demand curve DD represents the same conditions of demand at a
certain time. Generally, a change in demand results in a new demand curve which
represents new conditions of demand and time.
Y
D
Dz
Di
m
U
Dz
so
0
Qi
Q
02
X
Quantity
Figure 4.9 Change in demand curve.
In Figure 4.9, the original state of demand is represented by curve DD. The price is
OP and the quantity demanded is OQ. If there is a change in demand, represented b'
then at the old price of OP the quantity now demanded is 0Q 1 . This quantitl
is smaller than the former quantity. Similarly, a change of demand represented bi
the demand curve D 2 D 2 shows that at the same price of OP, a larger quantity of OQ
is demanded.
52
Factors affecting change in demand
Some of the factors bringing about a change in demand are:
• change in tastes and preferences
• change in income
4 •
Explain the relationship between the demand and
the price of a commodity.
•
•
•
•
•
•
Economic factors of production
replacement of old products with new ones (technical innovations)
change in the prices of other commodities
change in population
future trade expectations
taxes and duties
advertising the product.
Supply
supply ►
Supply is the quantity of a commodity that is placed on the market at a particular
time and at a certain price. This supply does not include the entire stock, but only
the amount that is brought on to the market at the prevailing price and time.
As with demand, the supply of a product is directly related to the price of that
product. Obviously, sellers want to release a larger amount of a product on the
market when the price is at a high level.
The supply schedule
supply schedule ►
supply prices ►
The supply schedule for a commodity is the grand total of all the amounts of the
individual sellers, tabulated to show the relationship between 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.
A supply curve (Figure 4.10) can be plotted using the data in Table 4.7.
8
7
Price per kg
($)
Quantity of
cabbage supplied
in kg
7.00
1100
6.50
1000
5.50
800
5.00
600
4.50
500
1
4.00
400
0
3.00
200
Table 4.7 A market supply schedule
for cabbage.
6
Ti
co
5
4
3
2
200
400
600
500
800
1000
1100
1200
Quantity of cabbage supplied (kg)
Figure 4.10
A supply curve for the cabbage data in Table 4.7.
Figure 4.11 shows a typical supply curve. This shows that a larger quantity 0Q 2 is
supplied at the higher price OP, and that the curve SS slopes upwards from left to
right.
P2
Q.
P
0
Q1
Q2
X
Quantity
Figure 4.11 A typical supply curve.
53
Section A: The B
usiness of Farmin.,
Section A: The Business of Farming
The 'law of supply'
'law of supply' ► The second law of supply and demand, also called the 'law of supply', states that
the higher the price, the greater the quantity that will be supplied.
Changes in supply
As with demand, a change in supply results in a new supply curve (Figure 4.12)
which represents new conditions of supply and time.
Y
F
0)
U
0
ul
u
n
U2
Quantity
Figure 4.12
Graph showing changes in supply.
In Figure 4.12, the initial state of supply is represented by the curve SS, the price is
OP and the quantity supplied is OQ. If some factor causes the supply to change, the
new conditions of supply are represented by S,S,, which is smaller than the former.
quantity. A change of supply represented by S 2 S 2 , indicates that at the same price
of OP, a larger quantity 0Q 2 is supplied.
Factors affecting change in supply
1 ri'
1i
List FOUR factors which affect the change in
supply of a product.
I
These factors cause a change in supply:
• high consumption of their own product by the producer (less product is
supplied to the market)
• change in cost of production
• change in technique of production
• changes in the weather
• taxation of commodities
• future expectations.
Pricing
Explain the term equilibrium price.
U
equilibrium price ►
M
The pricing of commodities
in a perfect market occurs
through 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.
Y
S
D
N
a`
P
M
s
0
0
Quantity
Figure 4.13
The equilibrium price.
4 Economic factors of production
equilibrium point ►
Figure 4.13 shows that at the price OP, the quantity supplied (OQ) is the same as
the quantity demanded (OQ). The point at which the demand curve DD intersects
with the supply curve SS is called the equilibrium point. At any price higher than
the equilibrium price OP, supply will exceed demand and the sellers will have a
substantial quantity of unsold products. At any price lower than the equilibrium
price OP demand will exceed supply and there will be a shortage of that particular
product.
The effect of changes in demand and supply
How is the price of a product 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.
Elasticity of demand and supply
elasticity ► Elasticity measures the degree of responsiveness of each of the market forces
elasticity of demand (E d ) ►
(supply and demand) to changes in price. It also enables the government to set up
appropriate policies to regulate the economy.
The elasticity of demand (E d ) is the degree of responsiveness of the demand for
a product to a change in its price.
It is expressed as:
Elasticity of demand (E
(Ed)
d =
percentage change in the quantity demanded
percentage change in price
Elasticity of demand may be:
• elastic — greater than 1: a small change in price results in a big change in the
quantity demanded
• inelastic — less than 1: a considerable change in price causes a small change in
the quantity demanded
• unitary — equal to 1: a change in the price brings about a proportionate change
in the quantity demanded.
elasticity of supply (E s ) ► Similarly, elasticity of supply (E s ) is the degree of responsiveness of supply to a
change of price.
Elasticity of supply (E
(Es)
=
s
percentage change in quantity supplied
percentage change in price
Elasticity of supply may be:
• elastic — greater than 1: a small change in price results in a big change in the
quantity supplied
• inelastic — less than 1: a considerable change in price causes a small change in
the quantity supplied
• unitary — equal to 1: a change in the price brings about a proportionate change
in the quantity supplied.
Price mechanisms
price mechanism ►
A price mechanism refers to a wide variety of ways to match up buyers and
sellers. It enables the distribution of scarce goods to consumers and scarce
factors of production to producers. The demand of consumers, or consumption,
encourages producers to expand their business. This stimulates demand for factors
of production and for an increased supply of commodities. Demand, supply and
55
" AV
The Bu
siness of Farming
Section A: The Business of Farming
price are dependent on one another and the equilibrium price equates de
with supply.
What is the purpose of raising prices by taxation? I The government may put price controls on certain commodities. Max
prices may be fixed for certain products to protect consumers, especially I
members of the community. Minimum fixed prices may be set to F
agricultural producers against a fall in income due to a bumper harvest.
Practical activity:
The purpose of raising prices by taxation is to reduce consumption of comm(
Practise plotting demand and
which are thought to be harmful to the economy. This can be done to t
the loss of foreign exchange as a result of the import of goods. Subsidies n
supply curves from data which
imposed on certain foodstuffs to keep the cost of living down or to encc
will be supplied by your teacher.
domestic production.
List F
suppl
Explain t
54
• The three major components of the economy of a country are prods
marketing and consumption.
• Production focuses on the manufacture of a wide range of goods ar
provision of services.
• Primary production is the production of goods or raw materials which n
consumed.
• Secondary production is the processing of goods and raw primary produ
• Production produces capital goods, luxury goods and consumable goods.
• Services may be commercial, technical or professional.
• Consumption involves the purchase and use of goods and services by cons.
It is the fuel which keeps the engine of production going.
• Consumption is influenced by income level, needs and health concerns.
• Marketing is the link between production and consumption. It promo'
flow of goods and services from the producer to the consumer.
• The key personnel in the marketing process are middlemen.
• Marketing functions can be classified into four groups: mercha:
handling, processing and supporting. Agricultural production is depen
land, labour, capital and management.
• Land may be owned, rented or leased. The suitability of land depend
topography and climate.
• Labour is a major factor in any agricultural enterprise. Small farms are
by farmers and rely on self-labour and family labour.
• Larger farms employ labour, which may be seasonal to cope with pla
harvesting, tasks for specific hours or contract work for land prepara
• Farm managers may be responsible for specific enterprises on large f
• Capital is needed for buying resources such as land, tractors and bui
• Farmers may obtain loans from institutions such as banks and credi
• Management is essential for the effective running of an agricultural
Good management is the ability to organise resources and combir
make a profit.
• Inputs are factors or resources which are used to achieve an outco
• In farming, the inputs are land, labour, planting materials, fertilisers a
• Fixed inputs are land, machinery and farm buildings. Variable inpr
seeds and fertilisers.
• Costs are the expenses involved in any enterprise. Fixed costs, su'
buildings, do not change; but variable costs change with the level
• Output is the quantity of product that is produced. It may be knc
return.
• Output is measured in units, e.g. tonnes of sugar cane or kilopotatoes.
'and
Rim
)rer
tea
ties
uce
be
a e
g
he
)e
s.
e
4 • Economic factors of production
• Increasing the number of outputs means that the number of inputs has to be
increased.
• Returns are the yield of the crop or the profit made.
• If an input (such as the quantity of fertiliser used) is increased, then the output
increases progressively up to a maximum point.
• The successive increase in total output for each additional unit of input is called
the marginal product.
• 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.
• 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.
• Demand is the quantity of a product which consumers are willing to buy at a
certain price at a particular time.
• The lower the price, the greater the quantity that will be demanded. The higher
the price, the greater the quantity that will be supplied.
• Supply is the quantity of a commodity placed on the market at a particular time
for a certain price.
• The pricing of commodities depends on the interaction of supply and demand.
• The equilibrium price is the price at which supply and demand are equal.
• Changes in supply and demand can alter the price of a commodity. Demand,
supply and price are dependent on one another.
1701
Production, consumption and marketing.
1T02 To satisfy people's wants; to promote economic welfare; to improve living
standards; to create wealth.
1703
Primary production refers to goods and products that are produced
initially, such as sugar cane and potatoes. Secondary production involves
the processing of the goods into manufactured items, such as sugar and
potato chips.
MN Consumption involves the purchase and use of goods and services by
consumers.
ITO Any four from: income level; satisfaction; religious beliefs; health reasons;
aesthetic reasons; product-substitutes.
IT06
Merchandising — includes buying, pricing and selling of goods.
Handling — transport of goods, assembling, grading and storing.
Processing — manufacturing, packaging and labelling.
Supporting — includes financing, enabling all other functions to be carried
out smoothly.
1107
Middlemen operate between producers and consumers. They act as
agents, brokers, wholesalers and retailers.
1108 The topography, whether hilly or flat; the climatic conditions, seasonal
fluctuations in rainfall and temperature; soil fertility and suitability for
different crops; cost of land.
1109
Land is used for housing schemes; over-cultivation and loss of soil fertility
also cause loss of agricultural land.
IT010 Labour is considered as the total cost and the total number of man-hours
involved in the production of a commodity.
11011 Self-labour and family labour can increase farm profits as no money is
actually paid out to the workers. The cost of the labour is not considered
as part of the cost of production.
17012 Capital resources available to farmers include commercial banks, credit
unions, co-operatives and agricultural banks.
57
W
Section A: The Business of Farming
IT013 Depreciation is when the monetary value and productive value of a
resource decreases with time.
IT014 The effective and efficient use of resources on the farm.
ITQ15 Planning, organising the workers, directing the workers, supervising farm
operations and managing the finances.
ITQ16 Inputs include land, machinery, labour, buildings, equipment, planting
materials, fertilisers and pesticides; anything which is put into an
agricultural enterprise to achieve an end result.
IT017 Fixed inputs are: land, tractor, buildings and equipment. Variable inputs
are: seeds, fertilisers, pesticides, fuel and labour.
11018 The quantity of product from a production process, otherwise known as
the yield or the return.
11019 Total cost is the fixed cost plus the variable cost (30 + 310 = 340).
Average cost is the total cost divided by the quantity produced
(340-4=85).
Marginal cost is the increase in total cost derived from the last unit
produced (340 — 270 = 70).
11020 Marginal return is the successive increase in total output for each
additional unit of input.
Diminishing return is the declining rate of increase of total output
resulting from each successive unit of input.
IT021 The law of diminishing returns states that if one or more inputs are
fixed and increasing amounts of one variable input are added, then the
marginal output per unit of the variable input will increase initially to a
certain point and then decline.
11022 4.
11023 The marginal product curve increases sharply, reaches a maximum and
then declines.
ITQ24 Stage 3 is described as the inefficient stage because money is wasted on
inputs that do not increase the output.
11025 The total cost of buying and transporting the goods, together with market
intelligence regarding supply and demand.
11026 The price and availability.
11027 The lower the price, the greater the quantity that will be demanded.
11028 Any four from: less supplied to market; change in cost; change in
technique of production; variations in weather conditions; taxation
changes; future expectations.
ITQ29 The price at which demand and supply are equal.
11030 Through the interaction of the forces of supply and demand at a
particular time.
11031 A tax is imposed on imported goods to benefit the economy by reducing
demand for foreign goods and the loss of foreign currency. At the same
time, it may encourage domestic production and consumption of certain
commodities.
58
• Economic factors of production
Examination-style
questions
Multiple Choice Questions
1. Which of the following is an example of secondary production?
A pineapples
B sweetcorn
C sugar
D eggs
2. Which of the following marketing functions deals with fixing the price of
products?
A merchandising
B handling
C processing
D supporting
3. 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 the crop
4. Working capital consists of:
A farm buildings
B equipment costs
C rent
D labour costs
5. Which of the following is a cost which varies with the level of
production?
A machinery
B buildings
C fuel
D land
6. 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) Distinguish between casual labour and permanent labour.
(b) What factors contribute to the farm labour problems in most
Caribbean countries?
8. (a) State the importance of management as it applies to agriculture.
(b) 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, specifying examples of each.
10. (a) What factors 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) State the law of demand.
(b) Draw a labelled diagram of a typical demand curve.
(c) List FOUR reasons for a change in demand for an agricultural product.
59
Section A: The Business of Farming
12. (a)
(b)
(c)
13. (a)
(b)
14. (a)
(b)
(c)
15. (a)
(b)
(c)
16. (a)
(b)
(c)
How is the pricing of commodities in a perfect market determined?
Using a labelled diagram, explain the meaning of equilibrium price.
Briefly discuss the 'price, supply and demand relationship'.
Distinguish between price control and subsidies.
Explain why price control measures are sometimes instituted by
governments.
Using appropriate examples, explain the meaning of:
(i) fixed inputs, and
(ii) variable inputs.
State the importance of inputs in an agricultural enterprise.
List some guidelines which farmers should adopt in selecting,
maintaining and utilising farm inputs.
Explain the meaning of: (i) fixed cost, and
(ii) variable cost, stating an example of each.
During 2004, Farmer Seema, who reared pigs, was charged water
rates at $210.00 per quarter, even though she used less water during
certain months of the year.
State (i) the name of this type of cost, and
(ii) the reason for your answer to (b)(i).
Farmer Seema paid Dr Marie for veterinary services on three
occasions during 2004 when a few of her pigs were ill.
(i) What type of cost was this?
(ii) State a reason for your answer to (c) (i).
Distinguish between input and output.
Explain how input, output and cost are interrelated.
Copy and complete the table which shows output-cost relationship:
Unit of
Output
1
2
3
4
5
(d)
60
($)
($)
($)
Fixed
Cost (FC)
20
20
20
20
20
Variable
Cost (VC)
-----130
190
Total Cost
(TC)
80
----210
264
($)
Average
Cost (AC)
80
75
-----66
($)
Marginal
Cost (MC)
80
-----
-----
36
----280
Explain the meaning of marginal cost.
----60
-----
............
Trade dgFEEITElltS
By the end of
this chapter
you should be
able to:
3
3
describe some international trade agreements that affect the Caribbean
understand how these trade agreements affect the agricultural sector
,,/ evaluate their effects on farming and on the peoples of the Caribbean.
Concept map
Trade agreements
International trade
agreements
Effects on the
Caribbean
Caribbean Single Market
and Economy (CSME)
World Trade
Organisation (WTO)
—
Agricultural sector
People
Free Trade Area of the
Americas (FTAA)
Lome I—IV
International Sugar
Agreement (ISA)
61
Section A: The Business of Farming
5.1 The effect of international trade
agreements
National Marketing and
Development Corporation
( NAMDEVCO) ►
If a country is to earn foreign currency, it needs to sell goods and services to other
countries. Often, international trade agreements involve goods and services from
one country being exchanged for the goods and services of another country. These
agreements have to be carefully set up.
In Trinidad and Tobago, the government operates the National Marketing and
Development Corporation (NAMDEVCO). The aim of this is to identify market
opportunities for agricultural products locally, regionally and abroad.
Some of the services of interest to exporters include:
• identifying export markets
• linking buyers, sellers and producers
• research into the requirements of foreign markets
• the provision of guidelines on variety, quantity, quality and packaging
• daily prices of commodities in international markets
• the provision of advice on insurance and finance to exporters and importers.
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 services
free movement
of goods
free movement
of capital
Figure 5.1
CSME.
free movement
of people
The functions of the
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).
The CSME (Figure 5.1) enables 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 and intra-regional markets.
Entrepreneurs in the CARICOM region are able to:
• use their talents and resources more fully
• trade freely without hindrance
• 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.
At present, there are 15 full members of CARICOM of whom 12 are members
of the CSME. Montserrat is a full member of CARICOM and awaits approval for
membership of the CSME. Haiti and the Bahamas are full members of CARICOM
but have not joined the CSME. The introduction of a single currency is scheduled
for completion between 2010 and 2015.
The removal of trade barriers and the opening up of new opportunities for over
6 million CARICOM nationals (14 million if Haiti is included) enables the CSME
to stimulate growth.
Free movement of goods
To enable free movement, the following measures will be taken:
• there will be no import duties on goods originating from the CARICOM region
• tariffs and quantitative restrictions will be removed in all member states
• intra-regional imports will be treated differently from extra-regional imports
• there will be agreed regional standards for the production of goods within the
CARICOM region providing a major incentive for high quality products from
producers and manufacturers
• CARICOM producers and manufacturers will be able to market their goods to
over 6 million people (14 million if Haiti is included).
62
5 Trade agreements
Free movement of services
Member states will be required to:
• remove impediments restricting 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 will:
• enable 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 will be removed
• promote and increase investment regionally
• allow firms access to a wider market for raising capital at competitive rates, so
enabling the productive sectors to become more competitive regionally and
internationally
• foster the development of a regional capital market which will increase the
attractiveness of the region for investment.
Free movement of people
What do the initials CSME stand for?
1
State the main role of the CSME.
1
List FOUR operations of the CSME.
1
Free movement of people will:
• promote a closer union among the people of the CARICOM member states
• abolish discrimination on grounds of nationality in all member states
• entail the removal of work permits for certain categories of workers
• encourage an interchange of managerial, professional and technical expertise
within the region
• enable 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, making it easier for
the marketing of produce, securing investments and the movement of workers. 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.
The World Trade Organisation (WTO)
World Trade Organisation ( WTO) ► The World Trade Organisation (WTO) is an international organisation which
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 absolute and all member countries must abide by
its rules. Any country that breaches the rules may have trade sanctions imposed
on it. As of July 2008, there were 153 member countries, representing 95% of
world trade.
Since 2001, the WTO has been trying to negotiate a trade agreement which
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
63
Section A: The Business of Farming
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.
Name THREE functions of the WTO.
The Free Trade Area of the Americas (FTAA)
Free Trade Area of the Americas
(FTAA)
►
FTAA objectives
create
regional integration
and free trade
conserve the
natural environmen
for future
generations
foster economic
growth
promote sustainable
development
reduce poverty and
discrimination
Figure 5.2 Objectives of the FTAA.
List the major objectives of the FTAA.
At the Summit of the Americas in Miami in December 1994, 34 countries of the
region agreed to the establishment of a Free Trade Area of the Americas (FTAA), in
which barriers to trade and investment were to be progressively eliminated. The
ultimate goal was to create an area of free trade and regional integration. The main
objectives are shown in Figure 5.2.
These objectives are similar to the objectives of CARICOM and the WTO, with
the emphasis on removing trade barriers and opening up markets to member
countries. Attempts have been made to ensure that any negotiations are
transparent, taking into account the differences in the levels of development and
the size of the economies in participating countries. It was agreed that negotiations
should contribute to the raising of living standards, the improvement of working
conditions and protection of the environment.
FTAA agreements are consistent with WTO rules. Member countries may
negotiate and accept obligations individually or collectively as a sub-regional group.
for example CARICOM. Some trade expansion has occurred through bi-lateral
trade deals with member countries and by the enlargement of existing agreements.
The FTAA has not yet come into full effect: its target deadline was 2005 but this
was missed. In June 2009, a fifth Summit of the Americas was held in Trinidad and
Tobago. The focus was on human prosperity, energy security, climate change and
sustainable development.
The FTAA has not progressed as far as CARICOM and the CSME, so its benefits to
Caribbean countries are limited. Where separate bi-lateral agreements have been
reached, there are advantages to participating countries, but these agreements are
not widespread and do not involve all countries.
The Lome Convention
Lome Convention ►
African, Caribbean and Pacific
(ACP) countries ►
Cotonou Agreement ►
64
The Lome Convention was a trade and aid agreement between the European
Community (EU) and 71 African, Caribbean and Pacific (ACP) countries. The
first agreement was signed in 1975. It came into force in 1976 and provided a
framework for co-operation between the members of the European Community
and the developing ACP countries, which were formerly British, Belgian, Dutch
and French colonies. The Convention allowed ACP agricultural and mineral exports
to enter the European Community free of duty, a quota system for sugar and beef
and 3 billion Euros of financial aid. Since 1976, the agreement has been renewed
three times (Lome II, III and IV) and in 2000 it was replaced by the Cotonou
Agreement. This was signed by 15 members of the EU and 79 ACP countries.
The partnership between Europe and the ACP countries has charted a course
from decolonisation to globalisation, geared towards global and political issues.
The Cotonou Agreement is expected to run for 20 years. It focuses on a global
approach to development and involves the progressive abolition of obstacles to
trade between the countries in accordance with the rules of the WTO.
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.
5 - Trade agreements
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 Organisation (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 5.3 The Cotonou Agreement - a summary.
What is the function of the Cotonou Agreement?
List FOUR major challenges which ACP countries
must face on the international market.
To improve the efficiency of production in the ACP countries, the Cotonou
Agreement makes provision for granting subsidies for long-term development
support and an investment facility to promote the private sector. The allocation
of financial resources will be based not only on their needs but also on their
performance levels.
The challenges facing the ACP countries are large but not insurmountable.
Enormous effort is required to strengthen their capabilities, relying not only on
their own resources but also on external assistance as provided by the Cotonou
Agreement. In this way, they will be able to adapt to developments in today's
world.
The International Sugar Agreement (ISA)
International Sugar Agreement In 1992, the International Sugar Agreement (ISA) was negotiated.
(ISA) ►
The objectives of the ISA are to:
• ensure international co-operation in connection with world sugar matters
• provide a forum for intergovernmental consultations on sugar and on ways to
improve the world sugar economy
• make trade easier by collecting and providing information on the world sugar
market and other sweeteners
• increase the demand for sugar, particularly for non-traditional uses.
International Sugar Organisation
The agreement is administered by the International Sugar Organisation (ISO)
(ISO) ► based in London.
There are 84 ISO member states, representing:
• 82 % of world sugar production
• 66% of world sugar consumption
• 93% of world exports
• 38% of world imports.
The ISO is the forum for the exchange of views between the major sugar producing,
consuming and trading countries. It carries out statistical analysis on the state of
the world markets and holds seminars to increase knowledge of the sugar market.
65
Section A: The Business of Farming
Which of the objectives of the ISA is of interest to
sugar growers of the region?
Practical activity:
Working in groups, choose
one of the specific trade
agreements. Design a poster
which summarises the agreement
and its relevance to trade in your
country.
66
1
Workshops are held on subjects of special interest to the sugar world. Topics hav■
included alternative uses of sugar and by-products, alternative uses of bagasse
opportunities for sugar technology and sugar consumption patterns.
Expanding from its traditional areas of sugar statistics, short-term and long
term forecasting and market analysis, the ISO is now tackling issues like suga
and health, sugar and the environment, fortifying sugar with vitamin A, organi
sugar and the promotion of sugar. Sugar-related products like alcohol, molasses
alternative sweeteners and biofuels are also of interest to the ISO.
Trade agreements are set up to sell goods and services to other countries.
In Trinidad and Tobago, NAMDEVCO identifies market opportunities fo
agricultural products locally, regionally and abroad.
• The Caribbean Single Market and Economy enables free movement of goods
services, capital and people across member states in the Caribbean.
• Entrepreneurs in the CARICOM region can trade freely and establish market
in other states.
They can invest and use funds in other states and hire skilled labour from an
member state.
• The removal of trade barriers within the Caribbean benefits the Caribbeai
region in international markets.
• Members of CSME will be able to market their goods to over 6 million peopl
in the Caribbean.
• There will be no import duties on goods originating from the CARICOM region
There will be no impediment to the provision of regional services.
Money can be transferred to any member state.
The development of a regional capital market will be encouraged.
Free movement of people will abolish discrimination on the grounds
nationality.
Interchange of managerial, professional and technical expertise will b
encouraged.
• The World Trade Organisation promotes free trade by persuading countries t
abolish tariffs on imports and other barriers to trade.
It is working to encourage trade agreements that promote and benefit ti
economy of poorer countries.
• The objectives of the Free Trade Area of the Americas are similar to those of I/
WTO and CARICOM with the main emphasis on the removal of trade barrie
and the opening up of markets to member countries.
It has not come into full effect and does not seem to have progressed as far
the CSME so its benefits to Caribbean countries are limited at the moment.
• The Lome Convention was a trade and aid agreement between the EU and t
ACP countries, which has been replaced by the Cotonou Agreement.
• This agreement aims to eradicate poverty in the ACP countries and to prom(
their entry into the world economy. The agreement provides for the granting
subsidies for long-term development support.
• The ACP countries need to be more competitive in international markets,
increase production and to attract investment.
• The International Sugar Agreement was set up to support countries wh
were involved in the production, export and import of sugar.
Its objectives are to ensure international co-operation in world sugar may
and to provide a forum for improving the sugar trade.
•
•
5 • Trade agreements
1101 CSME stands for Caribbean Single Market and Economy.
ITQ2 The removal of trade barriers between the countries of the Caribbean.
1103 The free movement of goods, services, capital and people in the Caribbean
countries.
IT04 Checking free trade agreements; settling international trade disputes;
organising trade negotiations.
ITQ5 To create regional integration and free trade; foster economic growth;
reduce poverty and discrimination; promote sustainable development;
conserve the natural environment for future generations.
1106 To eradicate poverty in the ACP countries and to promote their entry into
the world economy.
IT07 Competition on the international market; to increase production and
supply of goods; to maintain high standards; to attract inward investment.
IT08 To increase demand for sugar.
Examination-style
questions
Multiple Choice Questions
1. Which of the following organisations makes trade agreements only
within the Caribbean area?
A FTAA
B WTO
C CSME
D ISA
2. The Lome Convention was an agreement between:
A the European Union and the FTAA
B the European Union and the ACP countries
C the WTO and the European Union
D the FTAA and the European Union
3. 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
4. Which one of the following is NOT an objective of the Cotonou
Agreement?
A free movement of workers between countries
B abolishing obstacles to trade between countries
C eradication of poverty
D financial aid to developing countries
Short answer and essay-type questions
5. Explain why it is necessary for a producer to understand the
requirements of export markets before attempting to export goods to
other countries.
6. (a) What is meant by a trade agreement?
(b) Why are trade agreements beneficial to a country?
7. Describe the benefits of the Caribbean Single Market and Economy to
the agricultural sector.
8. (a) Explain how the Cotonou Agreement was set up.
(b) How does the Cotonou Agreement differ from other trade
agreements?
67
............
gl
farm financing and S WIM
HITCH
By the end of
this chapter
you should be
able to:
3
3
describe how capital can be obtained from established sources
3
3
understand how co-operatives work
know how to complete a sample application form
discuss the various incentives which may be given to farming.
Concept map
Farm financing and support services
Incentives to farming
Co-operatives
Obtaining capital
Collateral
Types
Subsidies
Credit history
Roles
Price support
Budget estimate
Function
Tax exemption
problems
Employment status
Management
problems
Project proposal
6 - Farm financing and support services
6.1 Sources of 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.
For the farmer, capital is both a physical and a financial resource; it is necessary
as the total investment for any agricultural enterprise. Capital includes land,
money, buildings, machinery and equipment, fuel and the raw materials needed
to produce crops and rear livestock. So capital can include stock as well as money.
CAPITAL
• a factor of production
• a physical and financial resource
• the total investment in the agribusiness
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 6.1 Fixed and working capital on a farm.
A farmer's capital resources can be divided into fixed (or durable) capital and
fixed capital ► operating (or working) capital. Fixed capital refers to those items on a farm that
have more than one year of productive life. These are items that only need to be
working capital ► renewed after many years. Working capital refers to those items which are needed
for the everyday running of the farm and which are used up in the production of
crops or livestock.
Working capital can be divided into two sub-groups:
stock ►
• stock or consumables, such as feed, fuel, fertilisers, pesticides and medication
cash ►
• cash needed to purchase land, replenish the stock of materials and to pay for
labour and other technical services.
depreciation ►
I
What is the meaning of capital to a farmer?
Explain the difference between fixed capital and
working capital, giving examples of each.
List reasons why capital is necessary for
agricultural enterprises.
Farm buildings, machinery and equipment undergo depreciation every year. This
means that each year they are worth a little less in financial terms. They also need
regular maintenance so that the maximum productive service can be derived from
them. Eventually the farmer has to replace these items because of their age, wear
and tear and obsolescence. Land tends to appreciate in value. This means that it is
worth a little more in financial terms each year. However, the farmer has to renew
its fertility on a continuing basis.
For many farmers, capital is a limiting factor. The amount of capital a farmer has
at his disposal enables him to:
• make decisions about the type and size of his farm, the type of crops to grow
and the best system to use
• decide on the level of mechanisation he can afford
• buy the farm inputs, such as land and stock, that he needs
• employ modern technology
• generate farm income and profits
• develop and improve the farming business
• increase farm assets and values.
69
Section A: The Business of Farrhing
Sources of capital
In the Caribbean, farmers may obtain capital, that is money (cash) and/or a stock
of ag ri cultural mate ri als, from the following sources:
1. Government institutions
Agricultural Development Bank
( ADB) ►
These 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% to 6%. The Ministry of
Agriculture arranges subsidised farm inputs (machinery, equipment, breeding
stock, sta rt er colonies of bees, hybrid seeds and other planting mate ri als).
They also arrange leases for state land.
2. Commercial banks/Enterp rises and insurance companies
The rates of interest from commercial banks, insurance companies and
financial agencies are higher than those from the government institutions
(8% to 14%). The commercial enterprises sell land, planting mate ri als,
machinery and equipment.
3. Credit Unions
These offer loans at low rates of interest.
4. Co-operatives and Associations
These organisations rent out machinery and equipment and offer loans at low
rates of interest. Depending on the nature of the co-operative or association,
planting mate ri als, breeding stock and sta rt er colonies of bees may be offered.
5. Sou-Sou Groups
In these friendly co-operative savings schemes, each person in a small group
contributes every week or month, as agreed, an equal po rt ion of money. 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.
6. Money-lenders
Loans from money-lenders have high rates of interest and relatively short
repayment times.
7. Personal savings
The farmer may have saved money over a period of time from the profits of
the farm.
8. Relatives
List FIVE sources of capital available to farmers.
I
This may take the form of a loan, at a reasonable rate of interest, borrowed
machinery and equipment, or an inhe ri tance of land, cash, buildings or
machinery and equipment.
^-
—
9. Friends
Name TWO government institutions and state the
type of capital which they can provide to farmers.
creditworthiness
farmer's
registration
lifestyle and
character
credit-rating
and reputation
LOAN
I
How to obtain loans
farm
p ro posal
budget
estimates
farm records
collateral,
security
and experience
guarantor
The farmer has to prove
several things before getting a loan.
Figure 6.2
Friends may offer loans at reasonable rates of interest, or land, machinery,
tree crops and livestock might be borrowed in a share-cropping arrangement.
To obtain a loan from a reputable financial institution, farmers need to fulfil ce rt ain
requirements (see Figure 6.2).
Farmer's registration
The applicant (farmer applying for a loan) must be a registered farmer. In Trinidad
and Tobago, the registration of farmers is done by the Ministry of Ag ri culture at
regional and county agricultural offices. Farmers who are registered are more
favourably considered for loans, subsidies and other national incentives. In other
terri to ri es, such as Jamaica, registration is via the Ministry of Agriculture.
6 • Farm financing and support services
Credit-worthiness
credit-worthiness ►
The credit-worthiness of a farmer is a measure of the farmer's ability to pay off debts.
It is determined on the basis of assets, liabilities and net worth. From information
supplied by the applicant, the lending institution will know the monthly income
and expenses of the farmer. They then judge whether he 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 credit-worthiness. Often such loans are insufficient
for the farmer to set up a new enterprise which 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 previously and repaid the loans promptly
is more favourably treated than someone who has not asked for credit before.
Normally, credit-rating and reputation are researched by the lending agency as
part of the application process.
The farm proposal and budget estimate
farm proposal ►
budget estimate ►
The farm proposal, outlines the farmer's intentions. It is a document which details
his objectives, the enterprises he proposes, his farming techniques, the resources
needed and the anticipated output and income.
Using his farm proposal, the farmer prepares and submits a budget estimate
for each of the enterprises he intends to pursue_The budget estimate justifies the
amount of loan required for the proposed farming business.
Some farmers approach financial agencies without detailed proposals and budget
estimates. Renowned lending institutions require carefully prepared proposals and
budget estimates and will not offer loans without these.
Farm records and experience
Farm records provide documentary evidence of previous enterprises and justify
the experience of the applicant. Many farmers keep poor farm records and are
unable to satisfy the lending institutions as to their ability to run an enterprise
successfully. It is difficult to judge the farming experience and 'track record' of an
applicant if there are no records.
Collateral, security, guarantor
collateral ► 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. This may be in the
form of property such as land, a house, farm machinery, equipment or livestock.
guarantor ► Often, a relative or friend serves as a guarantor, pledging their property as security
for recovery of the loan should the farmer fail to repay it. Some farmers who
operate small farms lack the collateral for loans and cannot find guarantors willing
to pledge their personal property as security.
Lifestyle and character
Honesty, sincerity, perseverance and a determination to work hard are character
traits which are highly regarded. Farmers should aim to be good role models as
they transact business with financial institutions.
Problems with obtaining loans
Lack of collateral, poor credit-worthiness, insufficiently detailed farm proposals
and budget estimates have been mentioned already as problems. In addition,
farmers who find it difficult to meet the loan requirements of some institutions
may be forced to take out loans with high rates of interest, or to make repayments
over a shortened period of time. These types of loans are stressful for farmers,
particularly if the agricultural enterprise is still being developed and not producing
much income.
71
Section A: The Business of Farming
Credit supervision
credit supervision ►
Some farmers may use their loans for purposes other than agriculture. Any 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 fanner the money in phases until the enterprise is completed.
List FOUR requirements which farmers need to
demonstrate when applying for a loan from a
reputable financial institution.
Practical activities:
1
1. Practise completing a loan application form.
2. Collect information from banks and financial institutions about loans and credit
facilities for farming enterprises.
Why is a farm proposal essential in an application
for a loan?
i.
What are the problems associated with high
interest loans?
co-operative ►
r
Why is a good credit-rating of benefit to an
applicant for a loan?
I
I
State the usefulness of credit supervision as it
applies to a loan made to a farmer.
6.2 Co-operatives
A co-operative is a legal organisation which enables its members, as a group, to
improve their economic status in a competitive society. A co-operative is a business
venture. It is voluntarily and collectively owned, controlled, operated, patronised
and managed by its members on a non-profit or cost basis for the economic benefit
of all its members.
A co-operative (see Table 6.1) can be distinguished from any other business
organisation by its guiding principles. These principles are referred to as the 'cooperative concept' (see Figure 6.3).
Principle
democratic
control
joint
ownership
open
membership
team
\ management
THE
CONCEPT:
GUIDING
PRINCIPLES
service
investments
patronmembers
non-profit
business
Figure 6.3 The co-operative concept.
Open
membership
Joint ownership
Democratic
control
Team
management
Patron-members
Non-profit
business
Serviceinvestments
Explanation
Membership is open to any person, regardless of gender, race,
colour or creed.
Each member is an owner of the co-operative.
Control of the co-operative is based on each member having
one vote and not on the amount of money a member has
invested.
Members operate and manage the co-operative as a team.
Members are the patrons or customers and users of the
services provided by the co-operative.
Generally, business transactions are non-profit making and
geared towards cost-recovery. However, any returns above cost
are shared equitably amongst all the members.
Members invest in the co-operative to be provided with certaix.
services and not for a profitable financial return.
Table 6.1 The major principles of co-operatives.
Roles and functions of co-operatives
Co-operatives fulfil the following roles:
• promote voluntary, open membership
• pursue business ventures
• encourage active participation and teamwork
• generate collective ownership
• encourage equity in sharing
• operate on a non-profit or cost basis
• improve the economic well-being of members
• provide desirable services to satisfy patron-owners
• generate greater bargaining power for better prices and contracts
• attract governmental aid, resulting in benefits for patron-farmers.
1p
72
6 - Farm financing and support services
Co-operatives are important organisations in many countries and fulfil many
functions. A co-operative helps its members to reduce operating costs, enables them
to increase their levels of production so that they can increase their income, and
challenges them to produce better quality produce and become more competitive.
In a wider sense, co-operatives encourage agricultural development and reduce
poverty.
Group demonstrations and technical training sessions are organised more easily
through co-operatives as members share a common interest. Greater interest in
productivity and business enterprise is created.
Types of co-operatives
Co-operatives can be grouped in two ways: by their function or by their links with
other groups.
Co-operatives grouped by function
There are seven types of co-operatives (see Table 6.2) which perform different
functions.
Type of
co-operative
Produce
Consumer
Purchasing
Processing
Marketing
Commodity
Service
Function
Members take part in joint-venture production enterprises
producing a range of products which are collectively owned.
This is organised for the bulk buying of consumer products
for the membership. The co-operative is owned, operated and
managed by its members.
This is engaged in bulk purchasing and supply of raw materials,
such as planting material, feed, chemicals and fertilisers, to its
members.
In this type of co-operative, 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
co-operative is named accordingly, for example Co-operative
Citrus Growers, Dairy Farmers' Co-operative and Cedros Fishing
Co-operative.
Each provides one or a combination of essential services to
members. There are service co-operatives for credit, livestock
breeding, farm machinery and equipment, transportation,
drainage and irrigation, cold storage, maintenance, security,
insurance, nursery and pre-school provision.
Table 6.2 The functions of different types of co-operatives.
Co-operatives grouped by links
Most co-operatives are linked in groups at local, regional and national levels:
• Local co-operatives offer members representation and services at the village or
district level.
• Regional co-operatives provide services and representation at the county or
regional level, based on nominees from local co-operatives.
• National co-operatives supply representation and services at national level,
through nominees from the regional co-operatives, who are representatives of
the various local groups.
73
Section A: The Business of Farming
What is a co-operative?
I
Name THREE different types of co-operatives and
explain the functions of each.
There are also:
• independent co-operatives, not affiliated to any other co-operatives
• federated co-operatives, comprised of small local co-operatives, operating
as an integrated unit and banded together for greater economic power and
efficiency
• centralised co-operatives, composed of delegates from local co-operatives,
operating as a centralised control unit and initiating directives from the local
co-operatives for action; the structure of these means that each member
cannot participate directly in the decision-making process.
Managing a farmers' co-operative
What are the major principles of co-operatives? Management of a farmers' co-operative is a shared responsibility between the Chief
business
volume
ineff ciency
limited
capital
membership
issues
ocai
competition
global
issues
Executive Officer, the Board of Directors and the patron-owner-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 co-operative. It uses managerial talents and
approved policies to achieve results using the limited resources available. Problems
may sometimes arise for the management team (see Figure 6.4).
Limited capital
Co-operatives operate with limited amounts of finance (or capital) which come
PROBLEMS
from its patron-members. It is not possible to provide a wide range of services or to
generate funds through public investment, as in a non-co-operative business. Such
Figure 6.4 Some problems in
procedures
are not allowed according to the co-operative concept. This means that
managing a farmers' co-operative,
the co-operative may have to seek 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
promptly.
Business volume
The volume of business transactions fluctuates between high and low. It depends
on how often members use the services they have provided for themselves. High
levels of business volume help a co-operative. It is up to members to ensure that
they use the services to sustain their co-operative.
Membership issues
Practical activities:
1. Visit an established farmers'
co-operative and find out how
it is organised and managed.
2. Find out about the different
types of co-operatives in your
area.
In a co-operative, each member is a patron, a user and an owner. Every member
needs to demonstrate a sense of ownership, loyalty and commitment. In some
cases, members do not give their full support by way of their share contributions
and business patronage. Members need to face up to the shared responsibility of
supporting their co-operative investment.
Local competition
Co-operatives often face competition from the local business community who feel
that they are an economic threat to their clients and business. Large local businesses
use bulk buying and obtain discounts from merchant suppliers. In retailing their
goods, they may offer lower prices than the co-operatives. Members of cooperatives need to focus their efforts on good management, greater production
and better quality.
Global issues
List the problems of managing a farmers'
co-operative.
74
Issues such as globalisation, trade liberalisation, competitiveness and quality
standards directly affect farmers' co-operatives. Such issues may make it difficult for
co-operative managers to meet the challenging task of international requirements
and to educate, train and motivate their members.
• Farm financing and support services
6.3 Incentives given to farming
Risk and uncertainty
The agricultural sector is affected by factors which involve risk and uncertainty.
These include:
• the weather
• natural disasters (volcanoes)
• over-production and under-production
• fluctuating market prices
• increasing costs of inputs
• unstable incomes of farmers.
Governments can help to stabilise production, market prices and farm incomes
through subsidies and price support policies.
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. They demonstrate commitment on the part of
the government.
In Trinidad and Tobago, price support is offered to farmers for the commodities
shown in Table 6.3.
Commodity
Guaranteed price ($)
Unit
Cocoa
12.00
kg
Coffee
11.00
kg
Oranges
21.00
crate
Grapefruit
13.00
crate
Rice paddy
2.20
kg
Milk
3.10
litre
Copra
3.04
kg
Corn (dry)
2.20
kg
Sugar cane
153.77
Table 6.3
tonne
Price support for selected commodities.
Subsidy
subsidy ►
tax exemptions ►
A subsidy is a financial incentive to farmers or producers for infrastructural
development, technical operations, purchasing farm inputs and establishing
agricultural enterprises. Normally, specific subsidies are offered to farmers, but the
government's commitment is only towards a percentage of the cost and up to a
maximum amount of money. Some examples are listed in Table 6.4, overleaf.
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.
icticat 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. Present your
findings to other groups in your class.
75
Section A: The Business of Farming
Agricultural
areas
Machinery and
equipment
Vehicles
Water for
agriculture
Q
Soil
What is the difference between price support and
a subsidy?
1
z
List FOUR functions of price supports and
subsidies.
conservation
Livestock
(ruminants)
Fisheries
Specific subsidies (examples)
% cost
Maximum $
Solar equipment and biodigesters.
50
5000.00
Trailers.
New tractors.
50
3000.00
15
25 000.00
New pickups and jeeps.
Wells, dams, ponds.
15
30 000.00
25
20 000.00
Irrigation equipment.
Contour drains per 30 metres.
50
25 000.00
100
70.00
100
370.00
50
2000.00
Contour banking, ridging or terracing
per ha.
Pasture establishment per ha.
Multipurpose boats.
10
5000.00
50
20 000.00
Tree crops
Aquaculture ponds.
Citrus establishment per ha.
Forestry
Cocoa/coffee rehabilitation per ha.
Watershed rehabilitation.
Nature trails per km.
20
2000.00
-
2000.00
50
2500.00
15
500.00
Table 6.4 Examples of subsidies.
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.
• Capital is a factor of production that is made up of fixed (or durable) capital and
working (or operating) capital.
• Fixed capital refers to land, buildings, machinery and equipment that do not
have to be purchased every year.
• Working capital refers to the items which are needed for the day-to-day running
of the farm.
• Capital plays a fundamental role in agricultural production. It enables the
farmer to plan, develop and operate the farm efficiently and profitably.
• Caribbean farmers usually obtain capital (money) from their government, as
well as from private financial institutions at varying rates of interest.
• The government institutions include the Agricultural Development Bank and
the Ministry of Agriculture.
• Commercial banks and insurance companies charge higher rates of interest
than the government institutions.
• Credit unions and co-operatives also lend money to farmers.
• Other sources of credit are moneylenders, friends and relatives.
76
6 Farm financing and support services
•
0
0
D
•
•
•
•
•
•
•
Farmers seeking loans from reputable financial institutions must fulfil certain
requirements. They need to provide details of their farming experience, provide
collateral and have a good credit rating.
Many farmers find difficulty in obtaining agricultural credit due to lack of
collateral, limited loans, high interest rates and a short repayment period.
A co-operative 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.
Some of the major principles of the co-operative concept include open
membership, democratic control, patron-members, team management and
non-profit business investments.
Based on their function and affiliation, co-operatives may be grouped into
various types, such as consumer, marketing, regional and federated.
A co-operative helps its members reduce operating costs, increases their levels
of production and helps them to become more competitive.
Management of a co-operative is a shared responsibility which needs managerial
ability, skills and experience. It must be goal-oriented, addressing problems proactively in a dynamic global environment.
Price supports and subsidies instituted by government help to stabilise
agricultural production, market prices and farm incomes.
1101
Capital includes land, money, buildings, machinery and equipment, fuel
and raw materials which can be used in the production of crops and the
rearing of livestock.
1102 Fixed capital is the land, buildings, machinery and equipment. Working
capital refers to items needed for the everyday running of the farm and
which are used up in the production of goods, such as fuel, fertilisers,
feed and seeds.
ITQ3
Capital is necessary to buy land, farm inputs, employ modem technology,
generate income and profits, develop and improve the business and
increase assets.
ITN Any five from: Agricultural Development Bank, Ministry of Agriculture,
credit unions, co-operatives, Sou-Sou groups, moneylenders, relatives,
friends, personal savings.
1105 The Agricultural Development Bank makes loans at low interest rates
to farmers. The Ministry of Agriculture subsidises farm inputs such as
machinery and breeding stock. It also leases land to farmers.
ITQ6 Four requirements from: registration, credit-worthiness, farm proposal,
budget estimate, farm records and experience, collateral, credit rating and
character.
ITQ7 The farm proposal contains details of the objectives, the farming
techniques to be used, the essential resources needed and the anticipated
output and income.
1108 High interest loans mean that it is expensive to borrow the money, and
the farmer may not be able to generate enough income to repay the loan
in the time period allowed.
MN A good credit-rating means that the applicant has borrowed money
before and repaid the loan promptly. This means that the financial
institution knows that this farmer is likely to submit a sensible proposal,
be successful and repay the loan on time.
11010 Credit supervision means that regular visits are made to the farmer to
observe the progress of the enterprise and ensure that the money is being
spent wisely. Technical advice can also be given.
77
Section A: The Business of Farming
11011 A co-operative is an organisation which is voluntarily and collectively
owned, controlled, operated, patronised and managed by its members on
a non-profit basis for their economic benefit.
11012 Any three from Table 6.2, such as produce, consumer, marketing,
processing and service, or reference to local, regional, national and
independent.
11013 The major principles of co-operatives are: open membership, joint
ownership, democratic control, team management, patron-members,
non-profit business and service investments.
11014 The problems of managing co-operatives are limited capital, business
volume, membership issues, local competition and global issues.
11015 A price support is a minimum, or guaranteed, price for selected crops
or commodities. A subsidy is financial assistance towards the cost of
purchasing farm machinery or other farm inputs.
11016 Speed up the growth of agricultural output; stabilise production, prices
and farm income; increase the supply of goods for home consumption
and for export; provide a regular income for farmers and producers.
Examination-style
questions
Multiple Choice Questions
1. 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
2. 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
3. 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
4. The function of a commodity co-operative 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
5. A regional co-operative:
A is not affiliated to any other co-operative
B consists of several small co-operatives
C has representatives from smaller co-operatives
D sends representatives to smaller co-operatives
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?
78
6 Farm financing and support services
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. (a) In procuring agricultural credit, farmers may encounter several
problems:
(i) List FIVE main problems which farmers may encounter, and
(ii) Discuss any THREE of the problems you have listed.
10. (a) List FIVE major roles for which co-operatives may be designed and
organised.
(b) Explain the importance of co-operatives in local agricultural
development.
11. (a) List FIVE problems which may arise as challenges for the
management team of a co-operative.
(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.
79
a.
f81ifi organisation and
planning
By the end of ,/ understand the need for record-keeping on a farm
this chapter ,/ prepare different types of farm records
you should be 3 distinguish between gross farm income and net farm income, gross margin
able to:
and net profit
3 use farm records on income and expenditure to determine profitability
3 prepare a partial and a complete budget
3 understand the relationship between budgeting and decision making.
Concept map
Farm organisation and planning
Income and expenditure
Farm records
Crop production
Gross income
Consumables,
e.g. chemicals
Net income
Gross margin
Livestock
production
Net profit
Farm inventory
Value of outputs
Financial
Fixed costs and
variable costs
Labour
80
Planning
Relationship
between budgeting
and decision making
7 Farm organisation and planning
7.1 Farm management and farm records
Farm management is essential to agriculture because agricultural enterprises by
themselves do not guarantee profitability. Farm resources need to be organised
farm planning ► and managed and the starting point of this is farm planning. The plans outline
the intentions of the farmer regarding the use of resources, the enterprise to be
pursued and the anticipated production.
There are four questions to be answered before starting on any new agricultural
enterprise. These are:
• What to produce?
• Why choose the product?
• How much to produce?
• How to achieve the production?
List the FOUR key questions that a farmer should
ask before planning a new enterprise.
What are the advantages of farm planning?
1I
short-term planning ►
long-term planning ►
What are the differences between short-term
planning and long-term planning?
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, taking into consideration the answers
to the key questions, eliminates some uncertainty. It also enables the farmer to
apply for a loan from a reputable financial institution. If progress of the planned
enterprise is recorded on a regular basis, there is information available for future
use.
Farm planning may be carried out on a short-term or a long-term basis. Shortterm planning relates to planning for enterprises for 1 year or for those with a
short production cycle. The main objective is to make as much profit as possible, so
the farmer chooses crops and livestock which will provide income in a few weeks
or months on a continuing basis. Such enterprises could be vegetable production
(pak choi, tomatoes and beans) or poultry production (broilers, ducks).
Long-term planning refers to planning for periods of longer than 1 year.
Usually plans are made for enterprises that need some time (1-3 years) 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. If a farmer is considering an enterprise requiring a long-term plan, then it is
advisable to undertake one or two short-term enterprises to produce some income
until the long-term projects become productive.
Figure 7.1 Poultry farming - a short-
term enterprise.
Figure 7.2 Growing citrus trees — a long-term enterprise.
81
Section A: The Business of Farming
Farm records
farm records ►
accessed or
retrieved easily
easily done
and kept
for prompt
follow-up action
kept
consistently
GOOD
FARM
RECORDS
for a definite
purpose
essential
information
simple, useful,
effective
accurate,
complete
Figure 7.3 The characteristics of good
farm records.
t
List FOUR characteristics of good farm records.
Farm records detail essential data about agricultural enterprises, and the farm as a
whole, in written or electronic form. The data should include records of transactions,
facts, information and observations. While a farmer may remember some of the
transactions carried out on a day-to-day basis, it is not possible to remember details
of figures, quantities and dates so it is vital to keep written records. The different
types of farm records are summarised in Table 7.1.
Farm records should:
• be easy to do and keep
• serve a definite purpose
• be simple, useful and effective
• be accurate and complete, giving the essential information
• be kept consistently
• be easily accessible.
Type of
record
Inventory
Production
Financial
Labour
Consumables
Examples
Land, machinery, tools and equipment, buildings, livestock, field
crops.
Crops, livestock, breeding, milk production, egg production, feed
conversion ratios.
Profit and loss account, assets, liabilities, balance sheet.
Personnel, permanent, casual, seasonal, contract, family.
Seed, fertilisers, pesticides, feed, medication, fuel.
Table 7.1 Types of farm records.
Farm inventory
farm inventory ► A farm inventory is a record of the farm resources, in terms of quantity and value,
at the beginning and end of an accounting period (normally one calendar year).
It includes 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 readily and
necessary action can be taken more promptly. An example of a separate inventory
system for tools and equipment is shown in Figure 7.4.
I
tool/equipment
Garden fork — heavy
_ . Carden fork —light Trenching spade
Weeding hoe
Brushing cutlass
Straight cutlass
. Watering can Knapsack sprayer
Hayfork
Weed watker
TOTAL
4
2
3
6
5
6
3
2
2
1
Ja. 01, 2007
480.00
480.00
150.00
270.00
360.00
300.00
330.00
240.00
480.00
160.00
2400.00
5170.00
Dec. 31, 2007
420.00
Damaged haedlu i.1w.
Very good coilifies
140.00
Good condition
240.00
Broken handles in three
300.00
Two need replacing
200.00
Broken handles in two
270.00
Two need repairing
180.00
Need servicing
400.00
120.00
Very good condition
2000.00
Exeell etl condition
4370.00
Figure 7.4 An inventory of tools and equipment.
Production records
production records ► Production records are used for crop and livestock enterprises to follow the prof
and determine the performance and productivity of different crop varieties
breeds of animals. With such records, farmers can find out whether inputs,
82
7 • Farm organisation and planning
as feed and fertiliser, are being used efficiently. This will ensure that high yield and
profitability are obtained on a consistent basis. 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 for fattening weaners. Similarly,
there are record forms for egg production and other types of livestock enterprises,
such as rabbit and broiler production.
Records for rabbit production
As an example, records for rabbit production should include:
• an animal inventory to include total number of bucks, does and weavers
• 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
(e.g. whether the doe was a good mother)
• feeding records, to include feed given, feeding regime, growth rate and feed
conversion ratios
• medication records
• 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. They also highlight problems where savings or improvements can be
made to make the enterprise more profitable in the long term. In 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. An example of a record form for a crop
of lettuce is shown in Figure 7.5.
Crop:
Variety:
Lettuce
Amt, planted or hectarage:
Iceberg
InputsAtems
—
—
Land preparation
3000
1
-- ^
Planting date:
heads
Type
• bruehcut
• plough
Quantity
N/A
Harvesting date or period:
04/06/2010
1 9 — 23/07/2010
Cost ($)
Remarks
120.00
Hired contract Iubour
Prerided ere truepe rt
• retavate
Planting material
• seedlings
20 Spedliy trryo
750.00
Fertilisers
• area
• Netree
50 kg
2 kg
350.00
90.00
Pesticides
• Meldhion
• Cuynoit
0.51
0.5 kg
95.00
85.00
Miscellaneous
Labour
Total cost of production
Yield/Output
Gross income
Profit/(Loss)
Figure 7.5 A record form for iceberg lettuce.
Chemical treatment record
Any treatment given to crops or livestock is a consumable resource, and needs
chemical treatments ► to be offset against any profit made. Chemical treatments include fertilisers and
83
Section A: The Business of Farming
pesticides for crops and medication, and concentrates and drugs for livestock.
Figure 7.6 shows a record form for the use of fertiliser. In the 'Remarks' column,
the farmer should record the crop to which fertiliser is applied. This is crossreferenced on the crop production record and the cost is offset against the profit
from sale of the crop.
Consumable item: Fertiliser — Urea
Utilisation
Purchases
Date
Quantity
purchased
Cost
Date
Quantity
used
Quantity
in stock
Balance
Remarks
List FOUR main types of farm records.
Describe the uses of production records.
7.2 Income and expenditure
income ► In small agricultural enterprises, financial records may take the form of income
expenditure ►
(farm receipts) and expenditure (farm expenses). Using these, a farmer will
determine his profit or loss.
In larger businesses, the financial records include:
• the profit and loss account (referred to as the cash account)
• the assets of the farm
• the liabilities of the farm
• the net worth statement or balance sheet.
Profit and loss account
profit and loss account ►
Figure 7.7 shows a profit and loss account for one month. The income is on the lefthand side and gives details of produce sold and price achieved. The expenditure
is on the right-hand side and includes labour, fuel and other consumables. The
only details missing from this account are the quantities of produce sold and the
consumables used. These would appear on the records for each enterprise on the
[arm.
Dr.
Particulars
Date
Expenses (Expenditure)
Cr.
Receipts (Income)
Value ($)
Particulars
Date
Value ($)
July 02 .
Cabbage
450.00
July 01
Labour
450.00
July 08
Bodi boons
210.00
July 05
Seedliugs
180.00
July 12
Eggs
320.00
July 09
Fertiliser
120.00
July 16
C..........
150.00
July 15
luseetieide
90.00
July 21
I'd Choi
120.00
July 23
Full
160.00
July 26
Eggs
300.00
July 28
Fuel: Pick-up
150.00
July 30
Nitro
140.00
July 31
Electricity
110.00
1690.00
total
Teal
1260.00
Figure 7.7 A profit and loss account for July.
balance sheet ► The balance sheet, or net worth statement, shows the value of assets left for the
farmer after all claims and liabilities against the business have been paid.
net worth = assets — liabilities
84
7 • Farm organisation and planning
A balance sheet is shown in Figure 7.8. The assets include the land, buildings,
machinery and equipment, field crops, livestock and cash. The liabilities include
unpaid rent and wages, mortgage commitment and money owing to creditors.
Assets
Value ($)
Liabilities
Value ($)
Land
125000.00
Wages
Buildings
60000.00
Rent
Machinery and Equipment
45000.00
Mortgage
Field crops
10000.00
Creditors
35000.00
Livestock
15000.00
Total liabilities
129200.00
Cash
50000.00
Net worth
Total assets
305000.00
28000.00
1200.00
65000.00
175800.00
304200.00
Figure 7.8 Balance sheet (net worth statement).
Income
income ► Income is money earned by producing commodities which are in demand and
selling them at current market prices to wholesalers, retailers and consumers.
After subtracting the costs of production, the farmer uses the income to purchase
necessities for the family, educate children, invest in savings, and buy the inputs
required to continue the farm operations.
In determining income, several factors have to be considered:
• fixed inputs and fixed costs (total fixed cost)
• variable inputs and variable costs (total variable cost)
• output and the market price gained (total income).
Production records
production record ► Figure 7.9 shows a production record for a duck rearing enterprise, where all the
costs are set out and the total income shown.
Fixed Inputs
Fixed Costs ($)
Land rental
Building
depreciation
Equipment
depreciation
Vehicle
depreciation
Insurance
Loan interest
60.00
500.00
Total Fixed
Costs (T.EC.)
250.00
900.00
Variable Inputs
Variable Costs
($)
OutpuWeld &
Market Price
Income ($)
Muscovy
ducklings
6000.00
Feed
15000.00
1500 live ducks
at
5 kg each
(avg wt)
7500 kg
at
$12.00 per kg
(Wholesale
market price)
7500 kg
r
$12.00
_ $90000.00
Total Income
= 90 000.00
Medication
Labour
500.00
12000.00
Electricity
550.00
550.00
240.00
Gasoline (Fuel)
850.00
Maintenance
600.00
= 2500.00
Total Variable
Costs (T.V.C.)
= 35 500.00
Figure 7.9 A duck production record.
From Figure 7.9, you can see that the total income is the market price multiplied
gross income ► by the number of ducks sold. This is $90 000 and represents the gross income, that
is the income regardless of 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 net income is $52 000 because the total cost of the inputs is
$35 500 plus $2500 (this equals $38 000). So $90 000 minus $38 000 = $52 000.
85
Section A: The Business of Farming
Explain the meaning of the terms farm income,
gross income and net income.
gross margin ►
net profit ►
How does the farmer use the income from the
farm?
Practical activity:
Use examples of farm records
provided by your teacher to
determine whether or not
an agricultural enterprise is
profitable.
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
Gross margin is an indication of how profitable an 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.
7.3 Partial and complete budgets
complete budget ►
A complete budget is also known as a total budget or a whole farm budget. It is
prepared for a farm which 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 7.10).
A Cawiplale Be4gat
_Ilatile
_ Pak el isi
_1000 btaikait$3.00Audla
1500 kg 0 no 00/4
- Sweet poplar_
Broilere
4000 kg @ AP-00AI
_JAW Income 1T.1.1 lifirdralle expenses_ WO
__Seedlings .......
___ „ Fertiliser
Pesticidal
_toiler eltidt
F et.
alleatiew
thalriallt
Wear
I rangwdatlea
latai filial. algoiiiiittil
a
fi
am
- Yate
ienses 0.0
22450M_
270.00
1200.00
750.00
1 500.00
-
Tsesaiiikva vaill114Telposses
_
36 000.00
_54_010.0.
1500.s00
2 500.00
1 200.00
3 000.00
600.00
450.00
550.00
6 500.00
750.0
as interest
lissraeee
-Di Lreeiatiee
Tatar e_W sapaasse LT.F.Ej.
Ti,.
-
------- $
3 000.00
15 000.00
3725.00
= T.T. =1.-TE.
= $54 000.00 - 322650.00
= 31350.0
is
Teter expestas [LEI
= T.Y.F. + T.F.E.
= $22 650.00 + $3 725.00
= $26 375.00
NM
= Tatar ieve
s
IT.T.Flifil an 00000 (T.11
= f54 000.00 - $26 375.00
= $27 625.00
Figure 7.10 A complete budget for a mixed farm.
partial budget ►
86
A partial budget is prepared when there is change in a specific aspect of the existing
farm plan that requires some modification to the budget. For example, a farmer
may decide to rear 6000 broiler birds instead of 4000, or purchase a pick-up truck
7 • Farm organisation and planning
What is meant by the term budgeting?
I
I
When is it necessa ry to prepare a complete
budget?
Describe the impo rt ant features of a pa rt ial
instead of hiring transportation. In such situations, most of the income (receipts)
and expenses (costs) in the existing budget will remain the same and only some
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.
The financial gains and losses are set out in the partial budget as:
• debits: additional costs and reduced income
• credits: additional income and reduced costs.
A Partial Budget
r)taya • Beatie8.1.i00_k reiler birl: ieote^ajlOQQbitds^_— __
•
•
1500.0
_ Feed
3 000.00
_ _
• 2000 k btsi en
a1.00k,
• R eieetie.325. 00
budget.
FieJ cub.
....
• None
Practical activity:
Prepare complete budgets for
some broiler and crop production
projects.
Using the example given here,
prepare a partial budget for an
increase in the number of broilers
reared from 4000 to 6000.
Total cuts:
_
__
iNe aTia ^^__
i11 enta .
costs
Broiierckickt __
11111111
Variable
_.._ - —
—
+ F.^.
NIL
Reduced_---------tiasi
• None
_
_25.
—482
5.00
NIL
^ 825. 00
i'ia^ is ra# TotTcre
r
ehd. it
_.._
-__ IS 000 00— 4 825.0 0
1311500
1800000___
825.00
NIL
-r.4 1 hVit
1800000
R^IroTath—
• Ntwe
NIL
-
A 11 en1--
--
NIL
is o00:o0
----
Figure 7.11 A partial budget for an increase in broiler production.
7.4 The relationship between budgeting and
decision-making
Decision-making
decision-making ►
identify problem
Decision-making is the ability to make sound,
objective judgements and initiate followgather information (data)
up action, based on all data and information
available. It is also the process of identifying,
analyse data
analysing and selecting the right course of action
to solve a problem.
formulate alternatives or solutions
All farmers and entrepreneurs involved in
farming are required to make decisions about farm
assess each alternative/solution
plans, budgets, work schedules, modifications
and improvements. Sound decision-making
results in farm profitability and development of
select the best alternative/solution
the business.
Decision-making (see Figure 7.12) is not a
evaluate the chosen alternative solution
simple matter for farmers. They have to consider
limited resources, changing weather, the
accept responsibility and results
unpredictable nature of production, the ups and
downs of the market and natural disasters. Hasty Figure 7.12 The process of
decision-making can bring economic losses and solving a problem by decisionbankruptcy.
making.
Budgeting
budgeting ► 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.
87
Section A: The Business of Farming
Reasons for budgeting
List FOUR factors which affect decision-making
by farmers in the Caribbean.
State TWO beneficial effects of sound decisionmaking.
How does budgeting help a farmer with decisionmaking?
• 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.
4=1;')
Farm planning is essential for the proper use of resources and the development
of agricultural enterprises.
• 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.
• Long-term planning involves enterprises which take from 1 to 3 years to come
into full production.
• Farm record-keeping is the process of registering essential data of agricultural
enterprises.
• Farm records provide valuable information for farm planning, decision-making
and budgeting. They are classified into: inventory, production, financial, labour
and consumables.
• Gross farm income refers to the total income from all the farm enterprises.
• The net income is the gross income minus the total costs of the inputs.
• Budgeting is estimating the quantity of inputs, costs, outputs, income and profit
of a farm plan.
• 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.
• 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.
• Decision-making in agriculture is the process of identifying, analysing and
selecting a course of action to solve a problem.
• Sound decision-making results in farm profitability and development of
agricultural business.
•
1T01
ITU
1103
What to produce? Why choose the product? How much to produce? How
to achieve the production?
Farm planning removes uncertainty, organises the use of farm resources,
focuses on production and enables the farmer to apply for a loan.
Short-term planning is for projects which last for a year or less, for
crops and for rearing livestock with a short production cycle. Long-term
planning is for projects lasting from 1 to 3 years.
ITN Four from: easy to do and keep; serve a definite purpose; simple, useful
and effective; be accurate and complete; be kept consistently; be easily
accessible.
1TC)5
11116
88
Four from: farm inventory; production; breeding; financial; labour;
consumables.
Production records are used to follow the progress, determine the
performance and productivity of different crop varieties and breeds of
animals.
7 - Farm organisation and planning
1107 Farm income is earned by producing and selling commodities. Gross
income is the total income gained by selling the product. Net income is
the gross income minus the total costs of the inputs.
IT08 The income from the farm is used to purchase the necessities for the
family, educate the children, invest in savings and buy the inputs for
continuation of the farm business.
1109 Budgeting is the process of estimating the total quantity of inputs, costs,
outputs, income and profits for an enterprise.
11010 A complete budget is prepared when a farm has a new owner or when it
is under new management. It can be prepared when an existing farm is
completely re-organised.
11011 The important features of a partial budget are the additional costs and
reduced income and the additional income and reduced costs.
11012 Decision-making in the Caribbean is affected by limited resources,
changing weather conditions, natural disaster, changing markets and the
unpredictable nature of production.
11013 Choosing the right course of action in solving a problem, farm profitability
and development of the business.
11014 It helps the farmer to decide which enterprise to choose in order to be
profitable.
Examination-style
questions
Multiple Choice Questions
1. Long-term planning is used for the production of:
A broilers
B milk
C lettuces
D tomatoes
2. Which type of farm records are used for recording the amounts of
fertiliser used?
A inventory
B production
C financial
D consumables
3. A farming enterprise recorded that the income from the sale of broilers
was $80 000. The fixed costs were $2500 and the variable costs were
$26 000. The farm profit was:
A $80 000 + $2500
B $80 000—$2500
C $80 000 — $28 500
D $80 000 — $26 500
4. Gross margin is:
A gross income — variable costs
B gross income — fixed costs
C gross income — total costs
D gross income — net income
5. 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
89
Section A: The Business of Farming
Short answer and essay-type questions
6. Discuss the statement 'decision-making is regarded as the heart of
farming'.
7. (a) Draw a diagram to show the stages in the process of decision-making
that farmers are advised to adopt.
(b) Describe TWO beneficial effects of sound decision-making.
8. (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 FIVE advantages of farm record-keeping.
12. (a) List THREE major kinds of financial records which farmers pursuing
large-scale agribusinesses should keep.
(b) Differentiate between (i) assets, and
(ii) liabilities.
(c) State the importance of financial records.
90
(11111111U1u,uunIur"
Soil
By the end of
this chapter
you should be
able to:
3
V
/
3
3
3
3
3
3
3
3
3
3
3
Concept map
feItIIIt V
describe the process of soil formation
know what a soil profile is and describe the major soil horizons
describe the major components of soil
describe the physical and chemical properties of major soil types
understand how major elements are recycled in nature
explain the factors affecting soil fertility
state the importance of the minor nutrients to crop production
interpret fertiliser ratios
explain how soil fertility can be maintained
describe how composting is carried out
define soil erosion
distinguish between different types of soil erosion
explain the causes of soil erosion
explain how soil and water can be conserved.
Soil fertility
physical
chemical
volcanic activity
animals and plants
human activities
soil organisms
Soil profile
lajor soil horizons:
characteristics
Soil types
lajor soil types:
sand
clay
loam
Soil properties
soil
Soil and soil fertility
Soil
Soil formation
and
•••••
Recycling of
elements
Factors
affecting soil
fertility
nutrients
pH
texture
structure
aeration
porosity
organic matter
mineral matter
soil temperature
soil water
Maintaining
soil fertility
I
Soil erosion
Role of microorganisms:
carbon cycle
nitrogen cycle
Terracing
Cropping systems
Weirs, drains,
ponds, tanks
Climate
Biotic
Topographic
Parent material
Management
I mportance of
minor nutrients
Amendments:
lime
NPK
organic manures
Cropping systems
•Composting
Soil and water
conservation
Types
water
wind
land clearing
poor land management
animal activities
Land management:
cover cropping
irrigation and
drainage
tillage
91
►t
Section B: Crop Production
8.1 Soil formation
weathering ►
bedrock ►
Soil on the Earth is like the skin on a mango, except that soil varies in composition,
type and thickness at different places.
Soil is formed by the weathering of rocks. Weathering is the decomposition of
Earth's rocks through direct contact with the planet's atmosphere. Soil may be
found overlying these rocks or it may be transported by natural forces, such as
water, wind and glacial action, and deposited at other sites. Soil is a mixture of
mineral particles, organic material, air and water. It provides an environment for
the growth of plants as well as a habitat for vast numbers of soil organisms.
Weathering involves the breakdown of bedrock (unweathered rock) into smaller
and smaller particles, together with the activities of plants, animals and humans.
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 then sandy soils result.
Soils formed in sloping or mountainous areas are shallow due to erosion, usually
by water. If there is a good vegetative cover with organic matter as a top layer, then
soil will form even on hillsides. But if there is erosion, then soil development occurs
only in the foot-hills and valleys with very little soil formed in higher regions.
There are three forms of weathering: mechanical (or physical), chemical and
biological.
Mechanical (or physical) weathering
Weathering due to ice
physical weathering ►
Physical weathering is the breakdown of rocks by mechanical means. If forces arc
applied to rock, either within the rock or from an external source, then the rock
breaks down. The most important type of physical weathering is brought about by
frost. In areas where the temperature falls below 0 °C, any water that has filtered
down into the cracks in the rock will freeze. As water freezes it expands and takes
up a larger space, exerting pressure and causing the cracks to get bigger. When the
temperature rises, the ice melts and the larger crack can hold more water. When
the temperature drops again, there will be more ice formed, yet more pressure and
the crack will get deeper. Eventually this process will break up rock into smaller
fragments.
After rain or snow melting
water
joint
(
On freezing, the water expands,
forcing the joints apart
ice
The ice melts and
eventually the rock is
broken up
Ego
rock
Figure 8.1 Freeze-thaw weathering.
Weathering due to moving water
Water in streams dislodges and carries away rock fragments. These collid
disintegrate and get worn down into small rounded pebbles and eventually miner
particles. Heavy rain also dislodges rock fragments and washes them into rivers. 1
coastal areas, waves beat on rocks causing them to disintegrate.
I
Weathering due to wind
In very dry regions, wind containing sand particles has an abrasive action at
wears away the surfaces of rocks. The particles of rock can be carried to other sit
•
where they are deposited.
92
8 Soil and soil fertility
Glaciers
Glaciers can cause weathering as they move down mountain slopes. They erode
rocks, transporting and depositing materials many kilometres away on lower
ground.
Weathering due to the sun
In the daytime, the sun heats up the surface of rocks causing them to expand. At
night, when temperatures drop, rock cools and contracts. Over a long period, the
continued expansion and contraction of the rock will cause it to fragment. This
is due to stresses set up as the surface expands more than the centre of the rock,
causing the surface layers to break away.
Chemical weathering
chemical weathering ► Chemical weathering is weathering which alters the chemical nature of the rock.
The main factors which cause chemical weathering are water, oxygen and carbon
dioxide.
Water
Rocks are made of materials which 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 which are soluble, but less so, include gypsum (calcium
sulphate) and carbonates, e.g. 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 forming clay.
Oxygen and carbon dioxide
oxidation ► 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. In
Write a definition for the term 'weathering'.
I most humid regions, other dilute inorganic acids (such as nitric and sulphuric),
and some organic acids are also important in weathering rocks.
rr
List the different types of weathering.
Biological weathering
biological weathering ► Biological weathering refers to 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 which
What are the effects of rainwater on carbonate
tunnel into the soil, such as worms, ants and moles, contribute to weathering by
rocks?
bringing new material to the surface where it is exposed to rainwater and the
r
'
atmosphere.
Describe how physical weathering occurs.
I
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
How do plant roots contribute to weathering?
I
dioxide breaks down carbonates (see above).
93
Section B: Crop Production
Volcanic activity and soil formation
Volcanic activity has occurred in several Caribbean islands, giving rise to igneous
rocks and volcanic soils. Volcanic soils are found on Grenada, St Vincent, St Lucia,
Dominica and Montserrat. The soil on slopes and in the valleys of the volcanic
cones is derived from the lava thrown out when an eruption occurs. Volcanic soils
are dark grey and have a granular structure. They are porous and high in sulphur,
phosphorus and potassium.
At the time of an eruption, volcanic ash is dispersed by volcanic pressure and by
the wind. It settles on the soil, where it appears as a fluffy, greyish layer. In the years
following an eruption, it becomes incorporated into the topsoil by 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 ►
micro-organisms, humus ►
Organic matter consists of the dead and decaying remains of plants and animals.
The accumulation of organic matter on the soil surface protects it from erosion
and encourages soil formation. Organic matter provides a source of energy for
micro-organisms which help to form humus. Humus is a brown or black substance
formed from decayed, and partially decayed, plant and animal material.
Humus is important as it:
• helps to bind sand and clay particles into clumps producing a granular soil (it
i mproves the texture)
• contains some of the nutrients which plants need.
Effects of soil organisms on soil
Figure 8.2 Earthworms in the soil.
List FOUR factors which affect soil formation.
Practical activities:
1. Make a poster to show how certain
soil types are associated with their
parent material.
2. Make a collection of soils formed
from different soil-forming 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
soils that still show evidence of
physical weathering.
94
Soil micro-organisms, such as bacteria and fungi, break down organic matter to
humus.
Earthworms (see Figure 8.2) contribute to soil formation and soil fertility
because they:
• make tunnels allowing air down into the soil
• create tunnels which contribute to the drainage of the soil
• make their tunnels by swallowing soil, so that the organic matter is digested
and mineral particles pass out of the gut back into the soil. In some species,
egested soil is deposited on the surface as a 'worm cast' and consists of finely
ground particles. The effect is to mix up layers of soil.
• pull leaves into their tunnels for food, increasing the organic content of the
soil and contributing to mixing.
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.
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 sub-surface layers
as well
• mining, quarrying and soil removal upset the activity of soil-organisms and
soil formation
• ploughing disturbs soil profiles but it does break up rock fragments.
8 Soil and soil fertility
8.2 The soil profile
soil profile ► A soil profile is a vertical section dug down through the soil showing a natural
sequence of horizontal layers of 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 8.3 shows a soil auger in use.
Soil horizons
soil horizon ► Each layer, or soil horizon, has different physical and chemical properties. The
development of a soil profile 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 0, A and B and may contain one or more
sub-horizons, which are named O„ O Z , A„ A 2 , A 3 and B„ B 2 , B3.
samples are laid out on the
ground in the order in which
they are removed from the
auger hole
1
2
3
4
5
6
Name of horizon
O horizon
Organic or litter
layer
A horizon
Zone of leaching or
eluviation
B horizon
Zone of
accumulation or
illuviation
Figure 8.3 Using an auger to obtain
soil samples.
C horizon
Parent material
Characteristic features
• 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 0 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
Table 8.1 Horizons and their characteristic features.
The importance of soil profiles
Draw a diagram to show a typical soil profile and
label the different horizons.
r:
Explain which horizons are affected when the
land is ploughed.
Practical activities:
1. Examine a soil profile and
measure the depth of the
different horizons.
2. Use a soil auger to determine
the characteristics of a soil
profile.
For the farmer, the soil profile is relevant in terms of land preparation needed
before planting crops. During ploughing, the furrow slice or topsoil is cut and
inverted by the plough-share. Depending on the thickness of horizons 0, A and
B, this slice may include horizon 0 and part of horizon A, or horizon 0, 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 with a sub-soiler.
furrow slice
(topsoil)
subsoil
parent
material 1
organic matter, leafmould, forest litter
O1
02 f1 O t1
—A1 lIrI
A { zone of leaching or eluviation
---------A3 )(
—81
•-------- ------- B2 ( B zone of accumulation or illuviation: a hardpan may develop
B3 I 1
C
1I C j parent material: zone devoid of biological activities
Figure 8.4 A typical soil profile
95
Section B: Crop Production
Depending on the soil profile, the farmer can decide on the depth of ploughing,
selection of equipment for tillage, and the choice of crops (shallow-rooted or deeprooted).
Types of soils
Latosols
Most soils in the Caribbean are
latosols ► latosols, formed when rainfall
is greater than evaporation and
there is rapid leaching of dissolved
minerals. These soils support dense,
tropical rainforest. The organic
layer (0 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 300 mm deep and
a dark brown to reddish colour. The
clay content makes the soil sticky.
Rainfall
greater than
evaporation
Little humus
mixed with
mineral matter
Rapid leaching
Strongly weathem
Accumulation
of organic
matter, iron
Brownish
yellow to
brownish red
and aluminium
clay with
B1
well-developed
angular, blocky
structure
Rendzina
rendzina ►
Another type of soil in the Caribbean
region is a rendzina, which
develops over limestone rocks. This
soil is thin, with the A horizon 200
to 250 mm deep. The soil is dark in
colour due to the amount of humus
and there is much animal activity.
Although there are rendzinas in
many Caribbean countries, they are
not widespread. The best examples
are on the plateaux of Jamaica.
Horizon
enriched with cis
Hard pan (iron
iron, aluminium
pan where
and/or other
there is a high
compounds
concentration
of iron)
Parent rock
Figure 8.5 Soil profile of a latosol.
8.3 The major components of soil
Soil is made up of:
• inorganic matter (mineral particles)
• organic matter
• water
• air.
The mineral particles and the organic matter (about
50%) are referred to as solids. The water and air,
which make up the remaining 50%, are referred
to as pore space. By volume, the solid fraction is
made up of 45% mineral particles and 5% organic
matter. The pore space fraction is divided into 25%
water and 25% air, both of which vary according
to weather conditions.
mineral matter
water
Figure 8.6 The major
components of soil.
Inorganic matter
The mineral component of soil, derived from the weathering of rocks, is porous
and consists of stones, gravel, sand, silt and clay. These components vary in size
and composition as shown in Table 8.2.
96
8 'Soil and soil fertility
Component
Stone and gravel remnants
Sand
Size of particles
Very coarse >2.0 mm
Coarse sand 2.0-0.2 mm
Silt
Fine sand 0.2-0.02mm
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, aluminium
developed through weathering.
Colloidal in nature; secondary minerals are formed through
weathering.
Table 8.2 The mineral components of soil.
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.
Organic matter
organic matter ►
Practical activity:
Shake up 100 g of soil in
500 cm 3 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.
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 microorganisms. 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 benefits the soil and
improves 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.
Soil water
field capacity ►
temporary wilting ►
permanent wilting ►
Soil water, from rainfall or irrigation, is needed for
capillary water
plant growth and for the soil organisms. It may be
present as a soil solution in the pore spaces or held soil particles
as a film around tiny mineral particles (adsorbed
water). Figure 8.7 shows this. Dissolved mineral
salts in the soil solution supply essential nutrients
for plants.
After rainfall, the soil may be saturated with
water. But following drainage, the level will reach
adsorbed water
field capacity, which is the optimum water level
for plant growth. At field capacity the larger pore Figure 8.7 Soil water:
spaces are filled with a continuous stream of water capillary water and adsorbed
which moves upwards by capillarity (capillary water.
water). This can be used by plants for photosynthesis. Excess water is lost from
plants by transpiration.
If soil water is lost and not replenished, crop plants begin to will during the
day but regain their turgidity at nightfall. 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 nightfall 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 death of the crop. Permanent
97
Section B: Crop Production
wilting is an indication that the capillary stream of water in the pore space is
broken. Plant roots are unable to take up the adsorbed water which is held tightly
round soil particles.
Soil air
soil aeration ►
llu y
List the different types of mineral particles in a
soil.
nyru
What is the organic matter in soil made up of?
Explain the relationship between soil air and soil
water.
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 which 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.
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.
8.4 The physical and chemical properties of
major soil types
What is the difference between a loam soil and a
sandy soil?
alluvial soils ►
colluvial soils ►
saline soils ►
The classification of soil types is based on the proportions of different-sized mineral
particles and the natural soil-forming processes. The sizes of the different mineral
particles are included in Table 8.2 on page 97.
It follows that:
• a clayey soil will contain a high proportion of clay particles
• a silty soil will consist mainly of silt particles
• a sandy soil will have more sand particles than other types
• a loam soil will contain about equal amounts of sand, silt and clay particles.
There are also other differences between soils. For example:
• gravelly soils contain large amounts of particles larger than 2 mm in diameter
• alluvial soils are formed through the action of running water, which erodes
rocks, transports mineral particles and 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 form due to the accumulation and
partial decomposition of organic matter
• saline soils are found in coastal areas affected by sea water and contain high
concentrations of salt; these are of little value in crop production.
Physical properties of soil
Soil texture
soil texture ►
98
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 8.8). For the
farmer, soil texture is related to the workability of the soil and how easy it is to
4
4
DE
th
8 - Soil and soil fe rt ility
plough. Some soils are 'light' as they are easy to till (sandy soils), some are 'heavy'
(clay soils), and others are 'intermediate' (loam soils).
Soil texture can be determined by three main techniques, which are summarised
in Table 8.3.
Technique
'Feel' method
Method
A small amount
of soil is rubbed
between the thumb
and fingers.
The soil sample is
made wet and then
kneaded.
Moulding
Mechanical
analysis (carried
out in the
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
Results of these techniques can be used
to check the other two and enable
the soil type to be determined more
Involves sieving,
sedimentation and
calculation,
laboratory)
accurately.
Table 8.3 Techniques for determining soil texture.
100% 0
clay
90
10
80 /
\ 20
70
30
clay
^^ 60
40 -oa
°m
Qe^^
5o
so
silty clay
sand
clay
40
sandy clay loam
20
10
Practical activity:
Use the 'feel' method and the
moulding technique to identify the
texture of samples of soil.
100%
silt loam
sandy loam
/o-
70
80
loam
sand
0
silty clay
loam
clay loam
30
r
60
Sin
SaI)o'
90
80
sand
70
60
50
40
30
20
10
100%
0 silt
percent sand
Figure 8.8 Soil textural classes based on particle-size distribution percentages.
Explain the meaning of soil texture.
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
Describe how soil texture can be determined by
the farmer in the field.
• workability of the soil; whether it is 'light' or 'heavy'
• ease with which roots can penetrate
• way in which crops respond to fertilisers.
place
Soil structure
soil structure ► Soil structure refers to the arrangement of the various particles, cemented together
into clusters (aggregates) which 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).
99
Section B: Crop Production
The aggregates may form:
• lumps with a diameter greater than 1 cm
• crumbs with a diameter from 5 to 10 mm
• granules with a diameter of less than 5 mm.
Aggregates (see Table 8.4) are classified into four major types.
Type
Laminar
Characteristics
• thin, flat, horizontal, leaf-like
plates
• pores and cracks are horizontal
Prism-like or • tops of aggregates are level (prismcolumnar
like) or rounded (columnar)
• faces are smooth and flat
• cracks and pores are vertical and
prominent
Blocky or
• surfaces are flat or rounded and fit
cubical
snugly when wet
• horizontal and vertical cracks and
pores well-developed
Spheroidal or • surfaces are rounded but do not
rounded
fit snugly when wet leaving pores
between them
Occurrence
Found in virgin soils,
leached soils (sub-soils) and
clay soils (kaolinite).
Found in clay loarns and
clays.
Found in heavy sub-soils
(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 8.4 Major types of aggregates and their characteristics.
Factors affecting aggregate formation
r•
Describe the type of aggregates that are found in
clayey loam soils.
List FIVE major factors which affect the formation
of aggregates.
filth ►
The following all affect the ease with which aggregates form:
• Climate: the effects of wetting, drying, freezing and thawing.
• 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: the binding effect of humus.
• Activities of plant roots: penetration, permeation, gum exudates and root
decay.
• Tillage operations: ploughing, rotovating, manuring and liming.
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.
Soil porosity and soil aeration
soil porosity ►
pi
tt
100
Soil porosity is the volume percentage of pore space in a lump of soil that is not
occupied by solid soil particles. It varies according to the soil type and the tilth.
A porous soil allows:
• water to percolate into the soil and become trapped as a film around mineral
particles after drainage
• air, containing oxygen, to enter the soil for the respiration of plant roots and
soil organisms
• plant roots to penetrate and grow freely in the soil
• soluble nutrients, from fertilisers and organic manures, to spread through the
soil and become available to plant roots.
8 • Soil and soil fertility
soil aeration ► Soil aeration is dependent on soil porosity and also on the amount of the pore
space which is occupied at any one time by soil water. Soil air and soil water
I
occupy the same pore space and the amounts of each will vary according to the
What is meant by soil porosity'?
I conditions. A well-drained soil contains more air than a waterlogged soil.
Practical activities:
1. Using a sandy soil, a clay soil and a loam, set up an experiment to find out which
soil drains more quickly 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 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 about 10 g of soil (M,) in a heatproof container.
b. Weigh the sample again (M 2 ) before heating it at a high temperature to burn off
the organic matter. Use a propane torch for this.
c. When the soil has cooled, re-weigh the sample (M3).
d. The quantity of organic matter can be calculated by subtracting M 3 from M2.
The quantity of water in the sample is given by subtracting M 2 from M, and the
quantity of mineral matter is given by M3.
Soil temperature and soil organisms
macro-organisms ►
State THREE major factors which affect soil
temperature.
State TWO beneficial effects of warm soil
temperatures on crop growth.
In the Caribbean, temperature on the soil surface ranges between 23°C and 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, vegetation 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
vegetation cover and which have little organic matter, lose moisture rapidly when
exposed to direct sunlight. Consequently, the soil temperature will rise.
Soil temperature affects:
• soil macro-organisms, such as earthworms, which are more actively
burrowing when it is warm
• soil microbial activity which increases when warm and decreases when cold
• roots of seedlings which are destroyed by high soil temperatures as plant cells
dehydrate due to evapo-transpiration
• germination of seeds which is more rapid under 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 soil temperature by mulching, cover cropping, intercropping,
irrigation, 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 8.9, overleaf. Fourteen of these are supplied by the soil.
The others (carbon, hydrogen and oxygen) come from air or water.
101
Section B: Crop Production
ESSENTIAL NUTRIENT ELEMENTS
Macronutrients (major)
Micronutrients (minor/trace)
• From the soil:
nitrogen
phosphorus ,` primary elements
potassium /
calcium
magnesium ,` secondary elements
1
sulphur
• From air and water:
carbon, hydrogen, oxygen
• From the soil:
iron
copper
zinc
manganese
cobalt
molybdenum
chlorine
boron
required in
small amounts
Figure 8.9 The essential nutrient elements.
macro-nutrients ►
micro-nutrients ►
primary elements ►
secondary elements ►
Fi
Nine of the elements are required in large quantities and are designated as macronutrients. The others are only required in 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 which is processed into dolomitic limestone and used as a liming material on
acidic soils to reduce the acidity.
In Figure 8.9, 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 Topic 8.6). 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.
The roles of the major nutrients in crop production are summarised in Table 8.5.
Nutrient
Role in crop production
Signs of deficiency
Nitrogen
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 fruitsetting.
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.
Stunted plant growth, poor root and shoot
development and yellowish leaves.
Phosphorus
Potassium
Calcium
Magnesium
Sulphur
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; late ripening of fruits.
Table 8.5 The roles of the major nutrients.
List the NINE macro-nutrients required by plants.
Which of these macro-nutrients come from soil?
The micro-nutrients are only required by plants in 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
Plants obtain soil nutrients from two main sources: the adsorbed nutrients on th
surfaces of clay and humus particles (colloids) and the dissolved minerals in tli
102
l
8 Soil and soil fertility
soil solution. These essential nutrient elements are present in the form of ions:
cations, anions ► cations which are positively charged (K', Ca" and Mg") and anions which are
negatively charged (Cl-, SO4 and NO 3 - ). 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 8.6 summarises
some soil minerals and their associated nutrient elements.
Group of
soil particles
Organic
Soil
particles
Humus
Soil minerals
Inorganic
Sand
Inorganic
Silt
Inorganic
Clay
Quartz, feldspars, micas,
hornblende.
Feldspars, micas,
haematite, limonite.
Kaolinite, illite,
montmorillonite,
vermiculite, chlorite.
Soil nutrient elements
Nitrogen, sulphur,
phosphorus, copper.
Potassium, calcium, iron,
magnesium, sodium.
Calcium, iron, sodium,
potassium, magnesium.
Magnesium, iron,
manganese, zinc.
Table 8.6 Soil minerals and their associated soil nutrient elements.
Leaching
leaching ►
micelle ►
Ir
Why are clay and humus particles important in
soils?
Once nutrients have been released into the soil, they maybe lost through leaching—
in this process soluble substances are removed by water. The nature and size of the
soil particles are directly related to 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 due to 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
which 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 ►
I/I
Explain what is meant by the pH of a soil.
Irc
Why are acid soils less fertile than alkaline soi
fl
The pH of the soil is a measure of the hydrogen ion concentration of the soil water.
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.
Soils in limestone areas are slightly alkaline due to particles of calcium carbonate.
Sandy soils tend to be slightly acidic because the rain causes leaching of soluble
ions which 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.
103
8 • Soil and soil fertility
soil aeration ► Soil aeration is dependent on soil porosity and also on the amount of the pore
space which is occupied at any one time by soil water. Soil air and soil water
occupy the same pore space and the amounts of each will vary according to the
conditions. A well-drained soil contains more air than a waterlogged soil.
What is meant by 'soil porosity'?
Practical activities:
1. Using a sandy soil, a clay soil and a loam, set up an experiment to find out which
soil drains more quickly 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 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 about 10 g of soil (M,) in a heatproof container.
b. Weigh the sample again (M 2 ) before heating it at a high temperature to burn off
the organic matter. Use a propane torch for this.
c. When the soil has cooled, re-weigh the sample (M3).
d. The quantity of organic matter can be calculated by subtracting M 3 from M2.
The quantity of water in the sample is given by subtracting M, from M, and the
quantity of mineral matter is given by M3.
Soil temperature and soil organisms
In the Caribbean, temperature on the soil surface ranges between 23°C and 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, vegetation 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
vegetation cover and which have little organic matter, lose moisture rapidly when
exposed to direct sunlight. Consequently, the soil temperature will rise.
Soil temperature affects:
macro-organisms ► • soil macro-organisms, such as earthworms, which are more actively
burrowing when it is warm
• soil microbial activity which increases when warm and decreases when cold
• roots of seedlings which are destroyed by high soil temperatures as plant cells
dehydrate due to evapo-transpiration
State THREE major factors which affect soil
temperature.
• germination of seeds which is more rapid under warm temperatures
• soil caking and crusting which occurs as a result of high soil temperatures,
direct sunlight and rapid loss of moisture.
State TWO beneficial effects of warm soil
temperatures on crop growth.
1
Farmers can lower soil temperature by mulching, cover cropping, intercropping,
irrigation, 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 8.9, overleaf. Fourteen of these are supplied by the soil.
The others (carbon, hydrogen and oxygen) come from air or water.
101
Section B: Crop Production
I ESSENTIAL NUTRIENT ELEMENTS
Macronutrients (major)
• From the soil:
nitrogen
phosphorus primary elements
potassium )
calcium
secondary elements
magnesium
sulphur
I
• From air and water:
carbon, hydrogen, oxygen
I
I
Micronutrients (minor/trace)
• From the soil:
iron
copper
zinc
manganese
required in
cobalt
((( small amounts
molybdenum
chlorine
boron
Figure 8.9 The essential nutrient elements.
macro-nutrients ►
micro-nutrients ►
primary elements ►
secondary elements ►
Nutrient
Nitrogen
Phosphorus
Potassium
Calcium
Magnesium
Sulphur
Nine of the elements are required in large quantities and are designated as macronut ri ents. The others are only required in small amounts and are the micronut ri ents or trace elements. The macro-nut ri ent elements are present in soils
as ions and may be de ri ved from the parent rock, released from organic matter
by the activities of soil micro-organisms, or added in the form of fe rt ilisers. For
example, calcium and magnesium occur in limestone and dolomite. Dolomite is a
rock which is processed into dolomitic limestone and used as a liming mate ri al on
acidic soils to reduce the acidity.
In Figure 8.9, 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 fe rt ilisers (see Topic 8.6). 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
fe rt iliser added to the soil.
The roles of the major nutrients in crop production are summarised in Table 8.5.
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 fruitsetting.
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 and 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; late ri pening of fruits.
Table 8.5 The roles of the major nut ri ents.
The micro-nut ri ents are only required by plants in very small quantities. If there is
^ ta 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 fe rt ilisers and added
List the NINE macro-nutrients required by plants.
Which of these macro-nu tr ients come from soil?
to the soil.
Soil particle-soil nutrient relationship
Plants obtain soil nutrients from two main sources: the adsorbed nutrients on the
surfaces of clay and humus pa rt icles (colloids) and the dissolved minerals in the
102
8 Soil and soil fertility
cations, anions ►
D-
ils
er
soil solution. These essential nutrient elements are present in the form of ions:
cations which are positively charged ( K . , Ca' and Mg') and anions which are
negatively charged (C1 - , SO4 and NO, - ). 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 8.6 summarises
some soil minerals and their associated nutrient elements.
Group of
soil particles
Organic
Soil
particles
Humus
Soil minerals
Inorganic
Sand
Inorganic
Silt
Inorganic
Clay
Quartz, feldspars, micas,
hornblende.
Feldspars, micas,
haematite, limonite.
Kaolinite, illite,
montmorillonite,
vermiculite, chlorite.
Dr
a
Soil nutrient elements
Nitrogen, sulphur,
phosphorus, copper.
Potassium, calcium, iron,
magnesium, sodium.
Calcium, iron, sodium,
potassium, magnesium.
Magnesium, iron,
manganese, zinc.
Table 8.6 Soil minerals and their associated soil nutrient elements.
re
of
leaching ►
rri
n.
Dr
to
5.
micelle ►
Why are clay and humus particles important in
soils?
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 are directly related to 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 due to 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
which 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 ►
Explain what is meant by the pH of a soil.
Why are acid soils less fertile than alkaline soils?
e
The pH of the soil is a measure of the hydrogen ion concentration of the soil water.
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.
Soils in limestone areas are slightly alkaline due to particles of calcium carbonate.
Sandy soils tend to be slightly acidic because the rain causes leaching of soluble
ions which 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.
103
Section B: Crop Production
Universal Indicator ► The pH can be determined using Universal Indicator test strips. Farmers an
interested in the pH of the soil as certain crops favour a certain pH. If necessary
they can adjust the pH to suit their crops.
8.5 The carbon and nitrogen cycles
The carbon and nitrogen cycles are important in making carbon and nitroger
compounds available for the activities of living organisms. Green plants are thi
producers ► producers, building up their food supplies from carbon dioxide, water and sunligh
(photosynthesis) and also using mineral ions from the soil.
consumers ►
The consumers are the animals which eat both plants and other animals.
decomposers ►
The decomposers in the soil, such as bacteria and fungi, break down the dea(
remains of other organisms, releasing nutrients for plants to use again.
Soil contains large numbers of micro-organisms, many involved in the recyclinj
of nutrients. Some of these organisms are shown in Table 8.7. Bacteria and fung
are of vital importance in nutrient recycling.
Name of group
Description
Role
Algae
Actinomycetes
Simple photosynthetic organisms.
Minute, threadlike organisms.
Single-celled organisms: spherical, spiral or
rod-shaped.
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 involved in other
mineral cycles; help break down organic matter.
Important in humus formation; effective in decomposing
plant materials, e.g. lignin and cellulose.
Bacteria
Fungi
Protozoa
Viruses
Some microscopic, some filamentous
forming visible structures, e.g. mushrooms.
Microscopic, single-celled organisms; few
present in most soils.
Microscopic; live in plant and animal cells.
Feed on soil bacteria.
Cause diseases in crops and livestock.
Table 8.7 Soil micro-organisms.
The carbon cycle
carbon cycle ► The carbon cycle (Figure 8.10) shows how carbon and carbon compounds ar
linked to natural processes and products. Three processes underpin the carbo
cycle: photosynthesis, respiration and decomposition.
in
)t,
is
Figure 8.10 The carbon cycle.
104
8 • Soil and soil fertility
photosynthesis ►
respiration ►
decomposition ►
Name TWO processes in plants associated with
the carbon cycle.
ITU25
Which groups of soil microbes are involved in
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.
Animals and humans, as consumers, 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, 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
burnt, carbon dioxide is released into the atmosphere. Coal and petroleum come
from plants which 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.
The nitrogen cycle
Nitrogen is essential for forming plant and animal protein. Figure 8.11 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 to nitrogen oxides,
which dissolve in rainwater and get washed into the soil as nitrates. Plants can use
nitrates and they absorb these through their roots.
nitrogen in
the air
plant and
animal protein
lightning
(nitrogen fixation)
denitrification
(denitrifying bacteria)
nitrogen-fixing
bacteria
Clostridium and
Azotobacter
plants eaten
by animals
root
nodules
urine and
faeces
yly
Rhizobium
nitrates are taken
up by plant roots
nitrification by
Nitrobacter
bacteria
nitrification by
Nitrosomonas
nitrites in
the soil
death and
decay
...b acteria and fungi
(decomposing
organisms)
ammonium
compounds
in the soil
Figure 8.11 The nitrogen cycle.
105
MW
Section B: Crop Production
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 causes nodules to form (see Figure 8.12).
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 to ammonium compounds, which can be used by some
plants or oxidised to nitrites and nitrates by other bacteria in the soil.
Nitrifying bacteria
Figure 8.12 Root nodules containing
nitrogen-fixing bacteria.
nitrifying bacteria ►
Explain the role of nitrifying bacteria in the
nitrogen cycle.
denitrifying bacteria ►
Name THREE nitrogen-fixing bacteria.
soil fertility ►
The organic matter which comes from the remains of plants and animals, urine,
faeces, crop residues and compost, undergoes decomposition by bacteria and fungi
in the soil and ammonium compounds are formed.
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.
8.6 The factors affecting 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:
• moderately porous with good aeration and drainage
• retains adequate moisture
• has a high organic matter content and is rich in nutrient elements
• has adequate permeability for roots
• is slightly acidic (optimum pH 5.5 to 6.5)
• is relatively free from toxins, pests and diseases.
Soil fertility is affected by climate, topography, the nature of the parent material,
fertilisers and soil management.
Climatic factors
In the Caribbean, climatic factors determine the crops that can be grown and the
livestock that can be reared. When first colonised by Europeans, the main crops
were those that would not grow in Europe but thrived in the Caribbean. Sugar
cane, coffee and cocoa were grown for export.
The climatic factors which determine where crops are grown are rainfall,
temperature, wind and humidity.
Rainfall
Rainfall is seasonal and varied in its intensity. In the rainy season, prolonged
rainfall results in waterlogged soils which prevent tillage and also affect the soil
organisms. Heavy rainfall causes flooding in low-lying areas and there is erosion of
soil, together with leaching of nutrients and damage to crops and livestock.
In the dry season, there is a lack of water and it is necessary to irrigate for crop
production to be successful. Many areas, particularly flat islands such as Antigua
and Barbados, have low mean annual rainfalls and prolonged periods of drought.
These dry periods harm plants and reduce productivity.
r.
kill
li [1I1
8 Soil and soil fertility
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). Although most territories have hilly
areas, there is not a great range of temperature variation.
Wind
Since the Caribbean area is mainly made up of small island states, it is windswept and cooled by sea breezes and the north-east trade winds. The winds mean
that a uniform temperature is maintained throughout any island, with occasional
variations. However, the area is prone to hurricanes with high winds and torrential
rainfall.
humidity ►
List the climatic factors which affect soil fertility.
Humidity
Humidity (a measure of the water content of the atmosphere) varies according to
the seasons. In the wet season, the humidity is high and in the dry season it is low.
Humid conditions do not affect soil fertility, but during periods of high humidity
there is greater spread of fungal diseases.
Biotic factors
Agricultural activities impact on soil fertility, especially those practices which involve
the preparation, use and tillage of the land. In clearing land for crop production, it is
poor practice to burn natural vegetation as this destroys organic matter in the soil.
The topsoil is exposed to erosion and soil organisms, especially micro-organisms
which bring about decomposition and the formation of humus, are destroyed.
Some agricultural practices, such as planting trees, help to conserve topsoil,
retain water in the soil and preserve the micro-organisms.
Topographic factors
How do topographic features affect soil fertility in
the Caribbean?
Most Caribbean countries are hilly and few have large areas of flat land. This affects
soil fertility in several ways. Soils on the slopes of mountains are shallow due to
erosion and the most fertile soils are in the valleys.
Because accessibility is limited in hilly areas, farmers find it difficult to till the soil
and improve soil fertility. There are restrictions on the use of heavy farm machinery
in such regions, so effective land preparation cannot be carried out. Farming in the
hilly areas is limited to small enterprises.
The nature of the parent material
parent material ► The parent material of soils consists of rocks which 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 which have become
consolidated and hardened geologically. They become weathered physically,
chemically and biologically to form soils.
Types of rocks
TYPES OF ROCKS
igneous ► Igneous rocks are formed from the
cooling and solidification of molten
rock. The major minerals in these rocks
Metamorphic
Igneous
Sedimentary
are quartz, micas and feldspars.
Examples:
Examples:
Examples:
• granite
• sandstone
• quartzite
sedimentary ►
Sedimentary rocks are formed from
• slate
• quartz
• shale
• micas
• li mestone
• schist
other rocks which have been weathered,
transported and deposited at the bottom
of swamps, lakes or seas through Figure 8.13 Types of rocks.
natural forces. As a result of geological
processes, heat and pressure the material becomes hardened into sedimentary
rocks. The minerals normally found in sedimentary rocks include sandstone, shale
and limestone.
107
Section B: Crop Production
metamorphic ►
Practical activity:
Test a range of soil types for
acidity and alkalinity.
Land management
rti
How does silviculture benefit soil fertility?
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.
Good management practices include:
• agro-forestry and silviculture which conserve topsoil and water and also
preserve the soil organisms
• application of fertilisers, organic matter and lime to improve the nutrient
status of the soil, maintain fertility and promote crop growth
• efficient land clearing
• avoiding the burning of vegetation
• pruning, tillage, drainage, mulching, staking, cover cropping and planting
shade trees on pastures — all these improve the soil condition.
agro-forestry ► Agro-forestry is a system of land use in which harvestable trees or shrubs are
silviculture ► 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
cause pollution of water and soil. There is also a risk of these chemicals destroying
the soil micro-organisms.
Inorganic and organic fertilisers
inorganic fertilisers ►
organic fertilisers ►
soil amendments ►
VA N
Pw
Metamorphic rocks result from changes which 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.
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.
l
Practical activity:
8.7 Importance of minor nutrients in crop
Set up experimental trials to grow
production
seedlings using a fertilised soil
and an unfertilised soil. Use the
same type of seedlings in each
experiment.
108
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 artificia'
fertilisers.
Organic fertilisers are derived from plant and animal remains. Organic fertiliser,
are referred to as manures or compost. They improve the structure, aeration an(
drainage of soils in addition to supplying nutrients.
Both manures and inorganic fertilisers supply nutrients. The manures maintail
and improve the soil's structural properties and supply essential nutrients. Th,
artificial fertilisers contribute a concentrated supply of essential soil nutrients bu
do not affect the structural properties of the soil.
Soil amendments describe substances such as lime, gypsum, sulphur, bagass(
coffee-hulls, manure and organic fertilisers which may be used to improve so
properties. These substances make the soil more productive, correct soil nuttier
deficiencies and replace nutrient elements lost through crop removal. Th
maintenance of soil fertility is described in Topic 8.10.
The minor nutrients are referred to as micro-nutrients or trace elements. They a
important for plant growth as they are found in many of the enzymes needed f
cells to function properly. It is not always easy to identify the effects of individu
elements. For example, yellowing of leaves could be due to a lack of magnesiiu
sulphur, nitrogen or iron (see Table 8.8).
8 Soil and soil fertility
Element
Manganese
Iron
Copper
Zinc
Molybdenum
Why is iron necessary for plant growth?
Boron
What is lacking in the soil if citrus plants show
signs of 'mottle leaf'?
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; 'sickleleaf' of cocoa.
Reduced growth; 'scald' disease
of beans.
Abnormal growth and death of
shoot tips; 'heart-rot' of beet;
'stem-crack' of celery.
Table 8.8 Minor (trace) elements, their functions and signs of deficiency.
8.8 Fertiliser ratio
simple fertilisers ►
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 muriate of potash
provides potassium.
What does fertiliser ratio mean?
compound fertilisers ►
fertiliser ratio ►
Mixed or compound fertilisers provide two or more of these elements in a simple
fertiliser ratio. Low grade fertilisers contain less than 25% of the nutrient elements,
medium grade contain between 25% and 40% and high grade more than 40%.
Manufacturers of fertilisers normally use labels which 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 (see Table 8.9).
Percentages N:P:K
5:10:5
10:10:10
10:20:10
12:12:18
22:11:11
21:14:14
20:20:20
Total nutrient content ( %)
20
30
40
42
44
49
60
N:P:K Nutrient ratio,"
1:2:1
1:1:1
1:2:1
1:1:1.5
2:1:1
1.5:1:1
1:1:1
Table 8.9 Nutrient ratios of some compound fertilisers.
From Table 8.9, we can see that some fertilisers have different percentages of total
nutrients but the same nutrient ratio. For example, NPK 5:10:5 and NPK 10:20:10
have the same nutrient ratio but their total nutrient content is different. NPK 5:10:5
has a total nutrient content of 20%, whereas NPK 10:20:10 has a total nutrient
content of 40%.
Fertilisers with a higher nutrient content will cost more. So while two fertilisers,
such as NPK 20:10:10 and NPK 10:5:5 with the same nutrient ratio of 2:1:1, may
be suitable for particular crops, the rates of application must be adjusted because
of the difference in their total nutrient content. If NPK 10:5:5 at the rate of
109
Section B: Crop Production
State the impo rt ance of the manufacturers' labels
on bags of fe rt iliser.
500 kg per hectare is recommended for a pa rt icular crop and the farmer only has
NPK 20:10:10, then he will need to apply 250 kg per hectare as this fe rt iliser has
twice the total nut ri ent content of the NPK 10:5:5.
8.9 Maintaining soil fertility
Explain what is meant by the fertiliser ratio.
Keeping the soil in a fertile state is a challenge for farmers. Several methods can
be used:
• soil amendments
• cropping systems
• soil and land management
• irri gation and drainage.
METHODS OR TECHNIQUES OF IMPROVING
AND MAINTAINING SOIL FERTILITY
cultural practices
cropping systems
soil amendments
erosion control measures
• moulding
• tillage
• drainage
• irrigation
• mulching
• crop rotation
• cover crops
• inter-cropping
• multiple cropping
• manures
• fertilisers
• compost
• organic matter
• liming materials
• vegetative cover
• strip cropping
• contouring
• grass barriers
• terracing
Figure 8.14 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 fertili ty. 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 fe rtilisers
• organic matter
• liming materials.
Manures
manures ► Manures are also known as organic fe rt ilisers and can be grouped as follows:
• pen manures are the partially decomposed solid materials derived from
livestock pens; consist of dung/droppings, bedding or litter; slurry from
washing pens of dairy cattle and other farm animals
• compost manure derived from the leaf litter and crop residues
• green manure refers to a green crop, preferably a legume, that is ploughed
into the soil at its flowering stage; adds nitrogen to the soil
• guano from the droppings from birds; contains large amounts of nitrogen and
potash
• bonemeal made by grinding bones from meat processing companies; contains
some nitrogen but large amounts of phosphate.
0^^r
t',Ptq.
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 slurry, it is spread
mechanically over ploughed land and pasture using a slur ry spreader.
Inorganic fe rt ilisers
inorganic fe rt ilisers ► Inorganic fertilisers may be simple inorganic fe rt ilisers, supplying one of the majpr
nutrients, or compound inorganic fe rt ilisers, supplying two or more nut ri ents.
110
8 •
NPK fertilisers ►
Soil and soil fertility
Some examples of simple fertilisers and the nutrients they supply are urea
(nitrogen), muriate of potash (potassium), triple superphosphate (phosphorus)
and ammonium sulphate (nitrogen and it 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 Topic 8.8).
There are several methods of applying fertilisers, depending on the type of
fertiliser, the area to be covered and the crop to which it is being applied. For largescale applications, the fertiliser is usually spread by machinery, but on small farms
it is done by hand.
lit
'‘..
• >'*•‘.:
.:.,:„. :„. . ,. „.. . , . . ?„,„. .„,:.:. _
,.broadcasting
fertiliser
.
•,
/No\
, .
fertiliser
row crop
3. row application
2. direct placement
soil surface
tree crop
•
, ,,,...
J
Al& /
4.;
44
„..„,,,,/! :11t...74.-
pk_L-scrn_i
upper slope
/
seed
lied)
c
fertiliser
4. band application
fe
fertiliser
in holes
r \■ ,
i\ CA' \ •
,,„.
•7 ,-....,
.....W •-••••
W.
ii
holes made with crowbar
7. hole placement
fertiliser on soil surface or
beneath soil
5. drill applies •
fertiliser
\
\
6. hillside application
N•
e
crop plants
*
8. soil incorporation
'-
liquid fertiliser
,..„4„
t'
--- f
21.
•
X =■
<09,
9. foliar application
Figure 8.15 Methods of applying fertilisers.
Farmers need to determine the fertiliser requirements of their crops. To do this,
several factors need to be taken into consideration (see Table 8.10).
Factor
Type of soil
Crop group
Crop stage
Weather
conditions
Table 8.10
Consideration
Determine whether soil is sandy, clay
or loam; nutrients are readily leached
from sandy soils; need to check pH of
soil as well.
Whether crop is leafy vegetable, cereal,
legume, root crop, cucurbit or fruit.
Crop has different nutrient
requirements at different stages of
growth.
Whether it is wet or dry at 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 reducing 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 be rapidly lost through leaching; if
it is too dry, nutrients may not be taken up by the crop.
Fertiliser requirements of crops.
111
F
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:
Watch demonstrations of different
methods of applying fertilisers.
Different methods of application are illustrated in Figure 8.15.
Organic matter
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 ► Liming materials are usually applied to acidic soils to reduce soil acidity, to increase
calcium and magnesium ions in the soil, to reduce the concentrations of iron,
aluminium and manganese, and to 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 [(CaCO 3 )], also known as chalk or ground limestone
• calcium magnesium carbonate [CaMg(CO 3 )] or dolomitic limestone.
What are soil amendments and why are they
used?
I ''
List FOUR factors that a farmer should consider
before adding fertiliser to his crops.
What are the benefits of adding lime to soils?
flI
Lime is usually applied to acidic soil during 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.
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 more speedy
and 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 Chapter 12). 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, draining 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 Chapter 12).
112
8 • Soil and soil fertility
8.10 Composting
composting ► Composting refers to the process by which organic matter (leaves, soft stems,
rejected fruits and vegetables) is decomposed to form compost manure. In making
compost, several essential components are required and each has its specific
function (see Table 8.11).
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
To undergo decomposition by micro-organisms to
form compost manure.
To introduce micro-organisms (decomposers) to the
compost heap.
To supply nitrogen which enables the microorganisms to multiply and increase their population.
To provide a suitable pH within the compost
environment, to encourage rapid microbial activity.
To provide moisture for a humid environment to
help microbial activity.
Table 8.11 Composting materials and their function.
Making compost
Phase 1 section Phase 2 section
concrete base
Figure 8.16 The composting area.
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 4.0 m long x 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.
The Phase 3 Section needs a protective cover
to prevent loss of nutrients through run-off and
leaching. A shed is useful for storing composted
storage shed with
material and to protect it from rain.
compost manure
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.
The Phase 1 Section is then built up as follows:
• 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
• 1.0 kg of sulphate of ammonia is broadcast over the organic matter layer
• 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 2.0 m is reached
• the heap is watered and kept loose and moist.
After 3 to 4 weeks, all the materials in the Phase 1 Section are transferred to the
Phase 2 Section, making sure that the 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 which time it is moved
to the Phase 3 Section. The compost is left to decompose here for another 3 to
113
Section B: Crop Production
r
Make a list of the materials which need to be
removed from waste before it is composted.
r4
Explain why fertiliser and limestone are added to
the compost heap.
Practical activity:
Prepare some compost following
the guidelines given above.
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 which 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.
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.
8.11 Soil erosion
soil erosion ►
Practical activity:
Carry out a demonstration of soil
erosion using models which you
have made.
r-i
Write a definition of soil erosion.
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. 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 vegetation cover is removed,
as when 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:
• amount of rainfall
• wind speed and intensity
• the type of rock
• the slope of the land
• the amount and type of vegetation cover
• the presence of grazing animals.
8.12 Different types of soil erosion
natural soil erosion ►
Soil erosion can be entirely due to natural causes or it can result from human
activities.
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, perched on an impervious layer, in hilly or
mountainous areas
• strong winds blowing over loose soil in dry, semi-arid or and (desert) areas
• sea-waves pounding the land in coastal areas.
accelerated soil erosion ► Accelerated soil erosion occurs as a result of the activities of human beings who
disturb the natural environment, creating soil conditions which 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 and removal of trees)
Name the TWO main types of soil erosion.
• mining and quarrying operations
• creating bare soil patches on the land by overweeding or brushcutting too
closely
• lack of ground cover, such as a cover crop or a mulch
List THREE causes of both the types of soil
erosion named in ITO 41.
• unsuitable cultural or soil conservation practices on hilly terrain.
114
8 • Soil and soil fertility
8.13 The causes of soil erosion
1
Water
In the Caribbean, soil erosion by water is a problem during the rainy season.
Type of erosion
Splash
Cause
Impact of heavy raindrops.
Sheet
Running water dislodges soil particles.
Rill
Water running down a bare area of sloping
land.
High intensity rainfall and fast-flowing water
on a sloping area of land.
Intensive rainfall on loose soil above a sloping
impervious layer.
Running water in hilly or mountainous areas.
Gully
Landslide
Loss of topsoil
Silting up of
water courses
Alluvial soil
deposits
Table 8.12
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
Soil particles carried away by running water.
Soil particles brought down mountainous
slopes by streams and rivers.
river banks and on flood plains.
The types, causes and effects of soil erosion by water.
0
°
1, 1
water flows downhill
p
O
0 aa
soil builds up
splash erosion
sheet erosion
rill erosion on a hillside
gully erosion (rills have joined together)
Figure 8.17 Some examples of soil erosion caused by water.
Wind
soil creep ►
saltation ►
Explain how wind can cause erosion.
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.
115
Section 8: Crop Production
Burning
burning vegetation ► Burning vegetation as part of land clearing has positive and negative effect
Among the positive effects are:
• unwanted material, such as cane-trash, is burnt out, so cane-cutters work
more efficiently
• land clearing can be carried out more speedily
`
• harmful plants, such as nettles, are destroyed
List TWO advantages and TWO disadvantages of
• harmful animals, such as snakes, scorpions, centipedes and the nests of wasps
burning vegetation when clearing land for crop
are destroyed
production.
• 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 i
the atmosphere. It is recommended instead that harmful plants and crop residue
are cut and stacked in an area where they can decompose slowly.
Other negative effects of burning vegetation are:
• the destruction of organic matter which 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 readily.
Animals
Any bare land exposed to heavy rainfall can lose nutrients through leaching an
mineral particles from run-off. The effects of animals, through grazing or trampling
can leave soil bare and open to erosion, particularly in the rainy season.
►
I
8.14 Soil and water conservation methods
`
soil conservation ► Soil conservation refers to protecting the soil from erosion and maintaining i
fertility. It is of great importance to agriculture in the Caribbean region.
Cultural practices which conserve the soil
minimum tillage ►
ridging ►
L
mulch ►
Cultural practices play a vital role in preventing soil erosion and maintaining sc
fertility.
Minimum tillage is where soil is only cultivated to provide the planting hole
and rows for the crops. It does not expose soil to rainwater and can therefo
reduce erosion in hilly and mountainous areas.
Ridging is where ridges are built across a slope to prevent the rapid flow of watt
downhill, and it can reduce soil erosion and help to retain water in the soil.
Organic matter, such as mulches or weeds that have been uprooted and If
lying on the soil, will reduce the direct impact of rain drops and allow water•
filter slowly down into the soil. A mulch is a protective covering over the s(
surface, usually of organic matter.
Rotational grazing helps to conserve pasture, because the animals are movt
around and the formation of bare patches is avoided (see page 243).
The importance of vegetative cover
vegetative cover ►
116
Vegetative cover (see Figure 8.18) refers to a layer of vegetation covering ti
surface of the soil. Vegetation is used to prevent soil erosion and includes ti
following practices:
8 • Soil and soil fertility
• the planting of cover crops, which grow and spread rapidly, providing a
protective covering on the ground (legumes are often used as cover crops)
• contour cropping where crops are cultivated along the contours of sloping land
• strip cropping where deep-rooted and shallow-rooted crops are cultivated
in strips,1 to 1.5 m wide, across a hill slope (this is very similar to contour
cropping)
• grass barriers (normally included in a strip cropping system); 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 dug across or down gentle slopes.
Figure 8.18 A cover crop: an
example of vegetative cover.
Forests and soil conservation
leaf litter ►
(iED
Identify FOUR different methods of using
vegetative cover to control soil erosion.
1
Now does terracing prevent soil erosion?
wind-breaks ►
Forests are very important 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 upper and lower
layers of the soil so that 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 and
forests may be established as wind-breaks 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, providing vegetative cover and shade.
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 wind-breaks.
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 ► Terracing involves the construction of relatively flat strips of land along the
contours of a hillside, forming a number of steps which are sometimes referred
to as bench terraces. The broad banks of earth prevent water running down the
slope, controlling soil loss and soil moisture.
contour ploughing ►
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 (see page 346).
Water conservation and soils
With a climate that has a rainy season and a dry season, water conservation is
essential on most Caribbean farms. Farmers depend on water storage systems,
drains and dry farming techniques.
Water storage systems
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 4500 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
117
Section B: Crop Production
Name TWO water storage systems which are
commonly found on farms.
gabions ►
another source of income for the farmer.
Wells can be dug out (from 3 to 10
metres 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 constructing dams, retaining walls or
directing the flow of flood water. 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.
Figure 8.19 A gabion retaining wall.
Drainage
Drainage channels are dug around fields and plots. These can drain away excess
water in the rainy season and 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 ► Dry farming techniques include any technique which conserves water or prevents
the evaporation of too much water from the soil surface in the dry season. These
techniques include minimum tillage, mulching, use of manure and compost and
cover crops. Controlled irrigation (using manual systems, hoses or sprinklers) may
be used to water crop plants in the dry season.
Practical activities:
1. Use an A-frame to establish
contour lines. See page 346 for
advice on using an A-frame.
2. Visit a watershed management
area.
118
• Soil consists of four components: mineral matter, organic matter, water and air.
• The mineral component is derived from rocks by physical, chemical and
biological weathering.
• Most physical weathering is brought about by frost, but stresses from roots, the
action of water, wind and the sun can contribute to breakdown of rocks.
• Chemical weathering alters the chemical nature of rock and can be brought
about by water, oxygen and carbonic acid.
• Biological weathering refers to the activities of living organisms which bring
about the disintegration of rocks and the formation of soil.
• Volcanic soils are formed from the magma and volcanic ash which follow an
eruption.
• Plant and animal matter is broken down by soil micro-organisms to form
humus.
• Some animals contribute to soil formation by burrowing, and plant roots create
channels in the soil.
• Farming activities such as land clearing, mining and tillage affect soil formation
and fertility.
• A soil profile refers to the vertical wall of a pit showing different horizontal
layers or soil horizons, each with varying physical and chemical properties.
• The mineral component of soil consists of different sized particles classified as
gravel, sand, silt and clay.
• The organic matter is made up of the dead and decaying remains of plants and
animals in the process of being broken down to form humus.
• The soil water, containing dissolved mineral salts, is present in the pore spaces
and as films around the tiny mineral particles.
8 • Soil and soil fertility
•
•
•
•
•
•
•
•
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Soil air depends on the air-water relationship in the pore spaces. It is important
for aeration, root respiration and biochemical processes.
Soils may be classified into sand, clay and loams, depending on the proportions
of the different sizes of the mineral particles.
Soil texture is dependent on the size and relative proportions of the different
mineral particles.
Soil structure is dependent on the aggregation of the mineral particles into
lumps and crumbs.
Soil porosity and soil aeration are interdependent and are affected by the
drainage of the soil.
Soil temperature affects living organisms in the soil, particularly the activities
of the micro-organisms. Mulching, vegetation cover and irrigation can help to
keep soils cool.
Soil contains 14 of the 17 essential mineral elements for plant growth.
Soil nutrients are present in the soil solution and also held around the colloidal
clay and humus particles.
Soil microbes are essential for the decomposition of organic matter, the
formation of humus and the recycling of mineral elements in the soil.
The carbon and nitrogen cycles show the transformations which these elements
undergo as they are cycled in nature.
Soil fertility is influenced by climatic, biotic and topographic factors, together
with the nature of the parent material and fertilisers.
Minor elements (trace elements) are important for the healthy growth of crops.
These are only required in tiny amounts but have significant effects on crop
production if lacking.
Inorganic fertilisers supply one or more of the three major nutrients, nitrogen,
phosphorus or potassium, and are graded according to the proportions of each
nutrient they contain.
Soil fertility is maintained by the application of soil amendments, the use of
different cropping systems, efficient soil and land management, irrigation and
drainage.
Soil amendments include fertilisers, manures, organic matter and liming
materials.
A farmer needs to work out which amendments are needed for the land and
any crops grown on it.
Liming materials reduce soil acidity, increase calcium and magnesium and
promote the activities of soil organisms.
Cropping systems and cultural practices help to maintain soil fertility.
Compost is made from waste plant material, such as leaves, soft stems, vegetable
peelings and rejected fruits.
A compost heap can be constructed using layers of pen manure, vegetable
waste, fertiliser and limestone.
Soil erosion is the process by which soil particles are carried from one area by
water or wind and deposited in another area.
Natural soil erosion occurs in a natural undisturbed environment but accelerated
soil erosion is caused by humans.
Soil erosion is caused by intensive rainfall which results in water running down
slopes carrying soil particles with it.
Wind can cause erosion in dry or semi-arid conditions where the soil particles
are loose.
Soil conservation involves retaining a cover of vegetation, planting forests,
contour-cropping, strip cropping, the formation of terraces and wind-breaks.
Water conservation measures include the use of storage tanks, building of pond
and pools and digging of wells.
:es
119
Section B: Crop Production
1101 Weathering is the breaking down of bedrock into smaller and smaller
particles by physical, chemical and biological processes.
1102 Physical, chemical and biological.
ITQ3 Physical weathering is brought about by the action of frost, water and
wind.
1104 Rainwater dissolves the carbonates in the rock, which then breaks up into
smaller fragments.
1105
Plant roots growing in cracks exert pressure which causes rocks to split.
1106 Volcanic activity, decaying organic matter, soil organisms and human
activities.
1107 Draw a diagram with all the horizons labelled and check with the diagram
on page 95.
1108 Depending on the thickness of each horizon, 0 will always be disturbed
and parts of A. If the A horizon is thin, then all of A and part of B will be
disturbed.
1109 Stones, sand, silt and clay; sand may be divided into fine sand and coarse
sand.
11010 Organic matter is composed of the fresh and decaying remains of plant
and animal material and humus.
11011 Soil air and soil water occupy the pore space in the soil. If there is a high
proportion of soil air, there will be less soil water and vice versa.
11012 A loam soil has a mixture of sand, silt and clay particles in more or less
equal proportions. A sandy soil has a larger proportion of sand particles.
11013 Soil texture refers to the coarseness or the fineness of the soil — the 'feel'
of the soil.
11014 The farmer can rub the soil between the thumb and fingers or the soil can
be made wet and moulded in the hand.
11015 Prism-like or columnar with smooth flat faces.
11016 Climate, activities of soil organisms, presence of humus, activities of roots,
tillage operations.
11017 Soil porosity is the volume of pore space in a lump of soil that is not
occupied by mineral particles.
11018 Three from: soil cover; sunlight; vegetation cover; soil moisture; organic
matter content.
11019 Microbial activity is increased, soil organisms are more active and the
germination of seeds is more rapid.
11020 The nine macro-nutrients are nitrogen, oxygen, hydrogen, carbon,
phosphorus, potassium, sulphur, calcium and magnesium. They all come
from the soil apart from carbon, hydrogen and oxygen.
IT021 Nutrients are adsorbed on to clay and humus particles. They have large
surface areas and surface charges which attract the nutrient ions and
water.
ITQ22 It is a measure of the hydrogen ion concentration of the soil water and
indicates the acidity or alkalinity of the soil.
ITQ23 The mineral salts are more soluble and more easily leached away in the
rainwater.
11024 Respiration and photosynthesis.
11025 Actinomycetes, bacteria and fungi.
11026 Nitrifying bacteria convert ammonium compounds to nitrites and nitrites
to nitrates.
120
8 • Soil and soil fertility
ITQ27 Rhizobium, Azotobacter and Clostridium.
ITQ28 Climatic factors affecting soil fertility are rainfall, temperature, wind and
humidity.
11029 Soils on the slopes of mountains and hills are shallow due to erosion.
Fertile soils are found in the valleys. The mountainous and hilly regions
are difficult to cultivate.
ITQ30 Topsoil and water in the soil are conserved. There is less erosion and the
activities of soil organisms are promoted by the organic matter in the
form of leaf litter on the soil.
II- 031 Iron is needed for the formation of chlorophyll molecules.
11032 There is a deficiency of zinc in the soil.
11033 The labels indicate the nutrient content and the nutrient ratio.
111134 It is the ratio of N, P and K in the fertiliser.
ITQ35 Soil amendments are materials that supply ingredients and nutrient
elements which improve soil fertility. Their function is to improve soil
structure, increase water-holding capacity and ensure drainage and
aeration.
ITQ36 Type of soil, crop group, crop stage and weather conditions.
ITQ37 Reduces soil acidity, increases calcium and magnesium and promotes the
activities of soil micro-organisms.
11038 List to include: bottles, plastic containers, tin cans, stones, woody stems,
nut grass and weed plants with seeds.
ITQ39 Fertiliser supplies nitrogen for the micro-organisms and the limestone
provides a suitable pH for the micro-organisms.
IT040 Soil erosion is the process by which mineral particles are carried away
from one area by water or wind and deposited in another area.
1 -1041 Natural soil erosion and accelerated soil erosion.
11042 Natural soil erosion: running water on steep slopes, landslides, strong
winds and sea waves. Accelerated soil erosion: burning, overgrazing,
deforestation, mining, quarrying, lack of ground cover.
11043 Wind can cause soil creep, which is gradual movement of particles on a
surface, and saltation of sand particles, where they become airborne in
strong winds.
11044 Advantages: unwanted material burnt, speedy land clearing, soil sterilised,
weeds burnt, harmful animals destroyed, potash added to the soil.
Disadvantages: destruction of organic matter and humus, soil organisms
killed, soil water lost, soil surface becomes bare, leaching of nutrients.
11045 Four from: cover crops, contour cropping, strip cropping, planting forest
trees, grass barriers, and grassed drains.
11046 The broad banks of earth prevent water running down the slope, so soil is
not washed away.
ITQ47 Two from: storage tanks, pools, ponds and wells.
121
Section B: Crop Production
Examination-style
questions
122
Multiple Choice Questions
1. Physical weathering of soil is caused by:
A carbonic acid
B oxygen
C wind
D humic acid
2. In a soil profile, the zone of leaching is the:
A 0 horizon
B A horizon
C B horizon
D C horizon
3. The percentage of organic matter in a loam soil is about:
A 50%
B 45%
C 25%
D 5%
4. The finest mineral particles in soil are:
A silt
B clay
C sand
D gravel
5. 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
6. Calcium is a macro-nutrient needed by plants for:
A protein synthesis
B chlorophyll formation
C development of root tips
D succulence of fruits
7. Protozoa in the soil:
A fix atmospheric nitrogen
B feed on soil bacteria
C decompose lignin and cellulose
D cause diseases in crops
8. Rhizobium is a bacterium involved in the process of:
A nitrification
B denitrification
C decomposition
D nitrogen fixation
9. 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
8 • Soil and soil fertility
Short answer and essay-type questions
11. (a) Explain the meaning of: (i) soil aeration (ii) soil porosity.
(b)
(c)
State the importance of 'soil porosity' in agriculture.
Why is it necessary for a farmer to aerate the soil of his vegetable
plot?
12. (a) Copy and label the typical soil-profile diagram below:
IV
(b) Name and describe the following layers:
(i) the layer marked II
(ii) the layer marked RI
(c) State the importance of the layer marked I.
13. (a) (i) Name FOUR major factors which affect soil temperature.
(ii) Discuss TWO of the factors you have named for (i).
(b) List FOUR practices which are used by farmers to lower soil
temperature.
(c) State TWO beneficial effects of optimum soil temperature in
Caribbean agriculture.
14. (a) What are the TWO main groups of soil particles which supply
nutrient elements to crop plants?
(b) State the major features which enable clay and humus soil particles
to attract nutrient ions and water.
(c) Differentiate between anions and cations.
(d) 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 which help to improve the physical environment, and
(ii) TWO which 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.
17. (a) List FIVE major factors which affect soil formation.
(b) Discuss any THREE of the factors which 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.
123
Section B: Crop Production
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 which should be considered in determining
the fertiliser needs of crops and soils.
(ii) Discuss any TWO of the factors which you have listed.
21. (a) (i) What is meaning of 'fertiliser ratio'?
(ii) List TWO fertilisers which have the same fertiliser ratio.
(b) The recommendation was N.P.K.: 10:20:10 at 500 kg per hectare but
Farmer Susan purchased N.P.K.: 5:10:5, because this was cheaper.
(i) At what rate should she apply the fertiliser purchased?
(ii) Give an explanation for your answer to (b) (i).
22. (a) (i) Explain the meaning of soil erosion.
(ii) Name TWO natural agents of soil erosion in the Caribbean.
(b) List and discuss the following measures used by farmers to control
soil erosion:
(i) TWO cultural practices
(ii) THREE vegetative covers
(iii) THREE mechanical devices.
124
111 1
I
..............
iieui
[and 1114 a ratio n
(I
By the end of
this chapter
you should be
able to:
3
3
3
3
3
3
3
3
describe the relationship between climate and agricultural production
measure rainfall and temperature
interpret weather records
use weather records in decision-making in farming
describe land preparation methods
explain the importance of machinery in crop production
describe the care and maintenance of simple tools and equipment
describe the safety precautions that should be taken when operating
tools, machinery and equipment.
Concept map
Land preparation
Climate and weather
Methods
Seasonality of
production
-
Machinery in crop husbandry
Land clearing
Tillage
Changing weather
patterns
—
measure
temperature and
rainfall
interpret weather
patterns
Drainage
Types
-seeders
- harvesters
-tractors
- attachments
Safety precautions
Levelling and
making beds
protective clothing
[ correct procedures
Care of simple
tools and
equipment
use weather
records in farming
decisions
125
Section B: Crop Production
9.1 The relationship between climate and
agricultural production
The fertility of the soil has a great influence on the types of crops that can be grown
and the crop yield. As we have seen in Chapter 8, the climate in the Caribbean has
affected the soil types and the maintenance of soil fertility. An alternation between
dry seasons and wet seasons means that farmers must be aware of the climatic
conditions when deciding what to grow, where to grow it and how to prepare the
land.
The Caribbean climate
tropical marine climate ► Most Caribbean countries have a tropical marine climate, with warm temperatures
all year round. This type of climate occurs on tropical islands in equatorial regions
situated between 5° and 25° north and south of the Equator. In the Caribbean,
the Atlantic Ocean and the Caribbean Sea are warm at all times of the year. The
average temperature is around 27°C, but there are variations depending on the
season. For example, in Jamaica the average temperature is 27°C in July and 24°C
in January.
There is a rainy season from May to October and the rest of the year is relatively
dry. During the rainy season, the northern and eastern sides of mountainous
islands get most of the rain. The southern and western sides can be dry, as they
are sheltered from the prevailing trade winds. In Dominica, which has mountain
peaks, there is an annual rainfall of 7600 mm, whereas in Barbados, which is
flatter, annual rainfall is around 1500 mm. The rainy season coincides with the
summer hurricane season.
hurricanes ► Hurricanes are very violent storms. They can occur at any time from June to
November, but are most frequent during August and September. They usually
develop over the ocean in the eastern Caribbean during the summer, when the
surface temperature of the sea is high and air pressure falls below 950 millibars.
Wind speeds of 120 to 250 km per hour occur and there is extremely heavy rainfall.
Hurricanes cause structural damage to property and crops, as well as flooding.
The effect of rainfall on plants
Explain what is meant by a tropical marine
climate.
-
II,.
Why is it important for a farmer to keep up-todate with weather forecasts?
Practical BCtlVlty:
Use the internet to follow the
tracks taken by this year's
hurricanes,
126
Due to the warm temperatures, plants that thrive in tropical conditions grow
quickly and germination is rapid. Rainfall, its amount and when it occurs, has a
much greater effect on agricultural production than temperature.
During the rainy season, it is important that the ground does not become
waterlogged, so efficient drainage is essential. in the dry season, irrigation is needed
for those crops that do not tolerate dry conditions. Some crops, such as cocoa and
bananas, need 2000 mm of rainfall annually, distributed throughout the year, if
they are to grow successfully. Other crops, such as sugar cane, corn and rice, need
most rainfall during the growing season. Sugar cane, in its early growing period
between May and August, requires heavy rainfall. This needs to be followed by
long periods of sunshine to increase the sugar content of the cane.
Forecasting the weather
Farmers need to know about the climatic conditions of the area they are cultivating
so that they can grow crops that are suited to the soil and climate. With better longterm weather forecasting, it is possible to predict changing weather patterns so that
harvesting, planting and spraying can be carried out at suitable times. Hurricane
warnings are given on the radio and television several days in advance. About 36
hours before a hurricane is due, a hurricane alert is issued and people are warned
to take precautions. Farmers try to ensure that their buildings areas safe as possible
and that their livestock are protected.
9 • Land preparation
9.2 Measuring rainfall and temperature
Measuring rainfall
rainfall totals ►
rain gauge ►
Rainfall totals are recorded every month (this is the
total amount of rain which has fallen in a month).
Information gathered over many years can show
the seasonal pattern of rainfall for an area. The
information in Table 9.1 indicates that there is a
wet season from May until October when a dry
season begins.
Month
Average
rainfall (mm)
January
20
February
10
March
22
April
27
May
102
Using a rain gauge
June
91
Rainfall is measured using a rain gauge. This
apparatus consists of:
• a large outer cylinder made of tin or copper
• a funnel with a small opening
• a jar in which the water is collected.
July
91
August
95
September
100
October
1 80
November
66
December
32
In addition, a measuring cylinder is needed to
measure the collected rainwater.
Table 9.1 Average rainfall
The outer cylinder is placed in the ground, partly figures for Kingston, Jamaica.
buried, to make it stable. It should be in a flat, open
space away from trees and tall buildings which could affect the amount of water
getting into the gauge (from splashing or from run-off). The funnel fits closely
to the top of the outer cylinder and water passes through into the collecting jar.
The jar is emptied every 24 hours. The quantity of water is measured using the
measuring cylinder and is then recorded in mm.
Rain enters the rain gauge
1 1
I
Knife-edge
ridge to
1
1
1
I
l
I
1
Measuring
cylinder
111
mm
I
i
_3
l
prevent
splashing
_2
t
Top section
with funnel
attached
_1
_0.5
Funnel with
very small
opening to
minimize
Bottom section
evaporation
containing the
of the water
collecting jar
collected
soil
surface
30 cm to prevent
splashing into
I the rain gauge
Buried in the ground
to stabilise the rain
Practical activity:
Set up and use a rain gauge.
Why should a rain gauge be placed away from
trees and buildings?
gauge
Figure 9.1 A rain gauge — this type of rain gauge can be easily set up in most
situations.
More modem electronic gauges, which measure and record the rainfall
automatically, are now used in most weather stations. A simple type of gauge can
be set up using a beaker or a measuring cylinder, but the measurements will not
be accurate as water will be lost due to evaporation.
127
Section B: Crop Production
Measuring temperature
,,
mercury
x
alcohol
temperature ► Temperature is a measure of how hot or cold something is. It is measured using a
thermometer, which consists of a glass tube containing a liquid. The liquid expands
when the temperature rises and contracts when the temperature falls. Sometimes
the liquid used is alcohol containing a red dye, but many scientific thermometers
use mercury. The glass tube is calibrated so that the temperature is easy to read off.
Scientific temperature measurements are made using the Celsius scale, where 0°C
is the temperature at which water freezes and 100°C is the temperature at which
water boils.
For recording climatic temperature data, it is usual to use maximum and
maximum thermometer ► minimum thermometers. The maximum thermometer records the highest
temperature reached during the period of measurement and the minimum
minimum thermometer ► thermometer records the lowest temperature. Inside each of the glass tubes of the
thermometers, there is a small piece of glass called an index.
The maximum thermometer contains mercury and when the
index
glass tube
temperature rises, the mercury pushes the index upwards. When
o o ,o p
b
o
° the temperature falls, the index is left behind and the maximum
temperature reached can be read by looking at the lower end of the
index and reading the figure from the scale.
The minimum thermometer contains alcohol. The alcohol expands
Note: The maximum temperature was 35°C
as the temperature rises and it rises up the tube, flowing past the
glass tube
index. When the temperature falls, the alcohol contracts and the
index
index is dragged down the tube. To read the minimum temperature,
x w
ro
the position of the end of the index closest to the edge of the alcohol
0
. .
is used.
When readings have been taken, the thermometers need to be
shaken to restore the index to the level of the fluid.
Note: The minimum temperature has been 20°C
Figure 9.2 A maximum thermometer (top) and a
minimum thermometer (bottom).
Stevenson screen ►
What is the difference between a maximum and a
minimum thermometer?
r•
Why are maximum and minimum thermometers
kept in a Stevenson screen?
Practical activity:
Set up and use maximum and
minimum thermometers to
compare temperatures over a
period of one month.
The Stevenson screen
If temperature comparisons between different areas are to be made,
then thermometers have to be kept in standard conditions. For this
purpose, the thermometers are kept in a Stevenson screen.
A Stevenson screen has the following features:
• it is painted white to reflect the
sunlight
• it has louvred sides allowing air to
flow freely around the instruments
• it should have a double roof;
the air space created is a poor
conductor of heat and the effect of
the heat from the sun will be less
• it is located on a grassy surface
well away from trees and buildings
• it should stand 112 cm above
ground level to decrease the
effect of heat conduction from the
ground.
Stevenson screens often contain other
recording instruments, such as wet
wet and dry bulb hygrometers ► and dry bulb hygrometers to measure
humidity.
Figure 9.3 A Stevenson screen for
housing weather-recording instruments.
128
9 • Land preparation
9.3 Interpreting weather records
meteorological organisations ►
The measurements made by meteorologists are used to forecast weather, either on
a short-term basis or over longer periods. Short-term forecasts are usually made
for periods of 5 to 7 days, but weather patterns can change quickly and farmers
should check the forecast on a daily basis, particularly if considering harvesting or
planting.
Observations are collected by the Caribbean meteorological organisations and
farmers obtain weather reports using the internet, radio and television. Certain
symbols, recognised internationally, are used to indicate the weather on maps.
Some of these are illustrated in Figure 9.4.
Interpreting symbols on weather maps is relatively straightforward. The symbols
for rainfall and wind speed indicate the quantity and nature of the rainfall expected
and the severity of the winds.
(a) Total cloud cover
0
1/8 o less
cover
No cloud
C-.-
1
/4 cloud
cover
(111 Ell 4111 0 • 0
Cill
3/
1
8 cloud
cover
/2 cloud
cover
5/
8 cloud
cover
3
/4 cloud
cover
7
/8 cloud
cover
No blue
sky
Sky
obscured
(b) Rainfall
•
••
•
•
Light and intermittent
V
Showers
Light and continuous
A
Hail
Moderate and intermittent
,
Drizzle
R.
Moderate and continuous
o
t
•
••
•••• •
.
R.
Thunderstorm with hail
— Fog
= Mist
— Haze
Speed
(knots)
Speed
(km/hr)
0
0
35
40
65
Heavt and intermittent
Heavy and continuous
Thunderstorm
.
(c) Wind strength
Symbol
0
O
1
II
II,
III
Speed
(knots)
Speed
(km/hr)
Symbol
Calm
Calm
III
Less than 9
11 1 1
9
1111r
0
45
83
19
1
Q
50
93
0
Less than 5
0
0
5
10
— - 5 knots
Note: Each half feather
A whole feather
I--- -10 knots
A shaded triangle L— - 50 knots
74
Q
Q
15
20
28
∎,
∎\
Q
55
60
102
37
Q
Q
25
46
k\'
Q
65
120
30
56
1\\
0
70
130
111
Practical activity:
Use the internet to find your local
(d) Fronts
weather forecast and the forecast
System
Symbol
Cold front
p
Warm front
Quasi-stationary front
for the Caribbean region. How
does the forecast weather differ
across the region?
,tors.
Intertropical Convergence Zone (narrow zone, one area of activity)
Il
Ca
Intertropical Convergence Zone (wide zone, two areas of activity)
Figure 9.4 Some international weather symbols representing cloud cover rainfall, wind strength and fronts.
129
Section B: Crop Production
Fronts
A front forms where different air masses meet. The symbols for fronts indicate the
boundaries between air masses that have different properties. The Caribbean is
affected by two air masses:
polar air mass ► • the polar air mass which originates in Canada and the USA in winter and
moves southward to the Caribbean
tropical maritime air mass ► • the tropical maritime air mass consisting of warm, moist air in the Gulf of
Mexico and the Caribbean Sea.
cold front ► Where the cold air mass meets the warm air mass, there is a cold front at the edge
warm front ► of the polar air and a warm front at the edge of the tropical air. When cold air
meets the warm, moist Caribbean air, it causes the warm air to rise. The warm air
is cooled, condensation takes place and rain clouds form. As a result, there is heavy
rainfall, thunderstorms, the temperature decreases and the wind changes speed
and direction. This type of weather is called the Northers because it originates
Name THREE sources of information about the
from North America.
weather.
As the cold air mass continues to move southwards, it becomes warmer until
eventually there is little difference between the temperatures of the two air masses.
Under these conditions, the cold air mass does not move much, the weather
quasi-stationary front ► conditions are more stable and a quasi-stationary front is established.
The ITCZ
r
When
Describe what happens when the polar air mass
t wo major air streams (the North East Trades and the South East Trades)
meets the tropical maritime air mass. meet, rain and thunder showers are produced. This happens because the air of
the South East Trades is cooler than that of the North East Trades and causes the
warmer air to rise and bring about the wet conditions.
Intertropical Convergence Zone
Where these two air streams meet is called the Intertropical Convergence Zone
(ITCZ) ► (ITCZ). This zone moves northwards during the northern summer, bringing heavy
rain to Trinidad and Tobago from June to August. During winter in the northern
hemisphere, the wind systems shift south of the Equator and from January to May
areas north of the Equator have their dry season.
1
N
V Miami
Gulf of Mexico
0
o^
0
'a
O
-- --
Tropic of Cancer
--- -------
ATLANTIC OCEAN
0 0
Cuba
------ 23½'N
------------
o
2
500 Km
o
NE Trade Winds
o
Jamaica
0
Q Dominica
Ca ribbean Sea
Key
Barbados
Warm air
t
E er
'
Cold air
Areas of convergence of air
1
NE Trades and SE Trades
2
Cold air from N. America
o a
0
Piarco
Trinidad
and warm air from the
Tropics
Figure 9.5 Convergence zones in the Caribbean.
130
Guyana
9 Land preparation
9.4 Weather records and farming decisions
Effects of heavy rain
leaching ►
During the wet season, nutrients are lost from the soil by leaching. In order to
maintain the fertility of the soil, farmers have to add fertilisers and manure,
together with using cultivation methods such as rotation of crops. Application of
fertilisers has to be timed to avoid heavy rainfall and fit in with the growth of the
crop. A farmer would be wasting money if he added fertiliser when heavy rainfall
was due — much of it would be leached.
Heavy seasonal rainfall floods low-lying areas and this can disrupt farming
activities. For example, if heavy rains come at the end of the sugar cane harvesting
season, then it becomes difficult to use heavy machinery. The fields are muddy, the
soil is churned up and the crop may be spoilt. To overcome this problem, extensive
drainage schemes have been set up in areas that are likely to be flooded. Often,
drainage channels can serve two purposes: removal of excess water in the rainy
season and irrigation in the dry season.
Effects of temperature
Although warm temperatures favour plant growth, they also encourage the
decomposing micro-organisms that are involved in the breakdown of organic
matter in the soil. Plant and animal remains are broken down quickly and the
humus content of the soil in warm areas is often low. In Chapter 8, the importance
of organic matter and the maintenance of soil fertility were described; farmers are
encouraged to use manure and compost as part of the regular treatment of their
land.
Warm temperatures also encourage pest organisms, such as aphids and mites,
which damage crops and cause diseases in animals. The use of pesticides and other
control methods has to be fitted into the farming operations. The weather forecast,
together with a knowledge of the life cycle of the pest, can help the farmer decide
on the best time to spray the crop or remove the disease-affected plants.
Hurricanes
Name TWO major effects of heavy rainfall on
farming.
The seasonal patterns of weather are more or less predictable each year: there will
be a rainy season and a dry season. Farmers can fit their operations to this cycle
of weather. The one feature that is less predictable is the occurrence of hurricanes
and tropical storms. The hurricane season extends from June to October, but
during that time there may be few hurricanes or many and their severity can vary.
Hurricanes can destroy buildings, infrastructure and communications as well as
disrupting the production of crops and the rearing of livestock. However, there
are warning systems and because the Caribbean lies in the path of such weather
systems, most farmers are aware of the dangers and take precautions.
9.5 Land preparation methods
Land preparation ensures that the soil is well-prepared before a crop is planted. It
involves clearing, tillage, fertilising the soil, liming, drainage, levelling the land and
bed formation.
Clearing
clearing ►
Clearing the land is normally the first operation. Depending on what the land was
previously used for, it usually involves removing trees, bushes and shrubs, tall
grasses or crop residues. Areas that had been abandoned and may have become
overgrown with trees and dense foliage may be cleared manually, using an axe or
a cutlass, or mechanically with a chainsaw and a bulldozer.
131
Section B: Crop Production
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 brush cutter attached to a tractor.
When land is bulldozed it is essential to save the topsoil.
The sequence when clearing land is:
• trees are removed and heaped in windrows
• topsoil is scraped off and placed in heaps
• land is graded, filling in any depressions
• topsoil is then spread 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.
cut trees and branches are heaped in a row
wooden
handle
List the equipment needed to remove trees from
abandoned land.
1
blade
1
I
How can bushes, crop residues and tall grasses
be removed from land mechanically?
1
Figure 9.6 A brushing cutlass (left) and a windrow (right).
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 the refining of the soil.
primary tillage ► In primary tillage, land which 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.
Figure 9.7 A tractor with a plough (primary tillage).
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.
At the end of primary tillage, the soil is in large clods or lumps.
132
9 Land preparation
secondary tillage ►
Using a hoe.
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 cutlass, or mechanically using a harrow and a rotovator.
Using a rake.
Using a cutlass.
Mechanical tillage using a harrow pulled by a tractor.
Using a rotovator.
Figure 9.8
Secondary tillage practices.
The effect of secondary tillage is to:
• obtain a tilth suited to the crop
• produce a seed-bed 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.
What is the meaning of tillage?
ITQ12
What is the difference between primary and
secondary tillage?
lanual methods
ommonly used by small-scale and
asant farmers.
an be used on hilly terrain as well as
flat or undulating land.
physical strength or physical
wer.
borious,, tedious and time-consuming.
ay be seriously affected by a scarcity
o
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.
List TWO advantages of manual methods of
tillage.
Table 9.2 Comparison of manual and mechanical methods of tillage.
133
Section B: Crop Production
Drainage
drainage ► It is essential to provide drainage for the removal of excess water from the surface
and sub-surface of the soil, especially during the rainy season. There are many
types of drains and drainage systems. These range from simple channels to complex
systems which can also provide irrigation during the dry season (see Figure 9.10).
The preparation of drains may be done manually, using a fork, spade, hoe, rake
and garden line; or drains can be dug mechanically using a ridger/banker (see
Figure 9.9) and a back hoe.
45-60 cm
1.5 m
„'e
15 cm
4
cm ^
60cm
30 cm
trench, canal or storm dram
V (vee) drain
box drain
Figure 9.9 A ridger/banker.
60-90 cm deep
tile drain (underground)
e
rubble drain (underground)
contour drains (on hillsides)
Figure 9.10 Some common types of drains.
Levelling and making beds
Practical activity:
Prepare some land for planting a
crop of your choice. The type of
crop will influence the amount of
preparation needed.
Why should levelling be done at the same time
that the land is being prepared for the crop?
134
After drains have been dug, the land needs to be levelled to form beds suited to
the crop, soil type, the season or weather conditions. During the dry season, flattopped beds may be used, but 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
Figure 9.11 Some examples of beds.
ridges and furrows
9 • Land preparation
9.6 Machinery used in crop husbandry
machine ►
Why have machines improved agricultural
production?
A machine may be defined as:
• an instrument or device used for carrying out a task
• any equipment or apparatus, specially designed for a particular purpose and
used for the transmission of force, power or motion to produce a desirable
effect.
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 re-designed and improved.
AGRICULTURAL MACHINES
1. have changed and
improved agricultural
production, worldwide
2. enable more farm work
to be done, more
effectively, per day
3. enable agricultural tasks
to be done more
efficiently, saving time
and money
4. help to red ce the cost
of production and to
increase farm profits
5. help to elle late drudgery,
motivating oung people
to take up agriculture as
a career
Figure 9.12 The importance of machines in crop husbandry.
Seeders
seeders ►
transplanters ►
Seeders, otherwise known as planters, may be of various types. Some consist of
drills, which sow seeds directly on to the soil. Sometimes drills combine seeds and
fertilisers, so that the seeds are planted with an appropriate fertiliser for the crop.
Transplanters are machines which plant seedlings such as tomato, sweet peppers
or 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 ►
combine harvesters ►
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 types are those
which can be attached to a
tractor, such as the sweet potato
harvester. This machine digs the
tubers, lifting them from the soil
on to a conveyer belt.
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
by special combine machines.
Figure 9.13 A sugar cane harvester.
135
Section B: Crop Production
Tractors
tractor ►
Which type of tractor would you recommend to a
farmer whose farm was 20 hectares?
What are the advantages of using a mechanical
seeder rather than sowing seeds by hand?
The tractor is one of the most useful pieces of farm machinery. It is mainly used
for pulling ploughs, harrows, cultivators and trailers, and for transmitting power
(by means of the power-take-off shaft) to attachments (brushcutters, rotovators,
fertiliser spreaders and threshers).
Tractors are built for use in different environmental situations and purposes.
Therefore tractors will vary in:
TRACTORS
• size
• horsepower (hp) or kilowatts (KW)
• mode of mobility: wheels or tracks
I I Crawler tractors
Wheeled tractors
• price, including resale value.
• two-wheeled tractors
• bulldozers
• four-wheeled tractors: I I • excavators
small
medium-sized
large
Figure 9.14
tractors.
Type of tractor
Two-wheeled:
e.g. Merry Tiller
Gravely
Four-wheeled:
Small
Four-wheeled:
Medium
Four-wheeled:
Large
Features
5 to10 horsepower or 3.75 to 7.5 KW engines
mounted on 2 wheels; 2 handles and lever
controls; attachments include brushcutter,
rotovator, rotary plough, trailer,
Gasoline or diesel engines; 10 to 20 horsepower
or 7.5 to 15.0 KW; small front wheels; large rear
wheels; pneumatic tyres; attachments include
brushcutter, plough, rotovator, trailer,
Engine capacity 30 to 60 hp or 22.4 to 44.8 KW;
si milar features to a small 4-wheeled tractor.
Same features as other 4-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 w heels.
I
I • graders
• loaders
• harvesters
The classification of
Uses
Suitable for smallholdings from I to 2.5 hectares;
tilling light soils on flat or gently sloping land; not
difficult to operate; not suitable for use on steep
slopes, rough land or dry clay soils.
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 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 welltrained an d skilf u l opera tors.
Table 9.3 Types of tractors.
Figure 9.15 A two-wheeled tractor. Figure 9.16 A four-wheeled tractor.
136
Figure 9.17 A crawler tractor with a
device for tilling attached.
9 • Land preparation
crawler tractors ► Crawler tractors are more powerful than wheeled tractors and have metal chain
What attachment would he needed to plough a
heavy clay soil?
I
List the functions of a harrow.
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 investing in a machine which might
not be used all the year round.
Tractor attachments
tractor attachments ► Tractor attachments are devices that fit onto tractors. They make agricultural
operations easier, saving time and labour. Table 9.4 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
Chisel plough
Rotovator
Harrow
Brushcutter
Trailer
Fertiliser spreader
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
• ploughing 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 draw-bar of tractor
• transport 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
• pumped from a boom with 'fan-type' or 'hollow cone' nozzles
• can be calibrated to spray the right amount
-1
Table 9.4 Tractor attachments and their uses.
Figure 9.18 A disc plough.
Figure 9.19 A chisel Figure 9.20 A fertiliser
plough.
spreader.
Figure 9.21 A
mouldboard plough.
137
Section B: Crop Production
9.7 Care and maintenance
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.
Major practices for the maintenance of tools and equipment are summarised in
Table 9.5.
Practice
Cleaning
Drying
Sharpening
Repairing
Painting
Oiling or
greasing
Storing
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 pr otect them, p rolonging 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 a tool rack, cupboards and shelves; to prevent rusting, avoid
storing tools close t o fertilise rs.
Table 9.5 Care and maintenance of tools.
Keeping records
tr i
Describe how tools and equipment should be
stored safely.
tr
g
Now can you prevent tools from becomin
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, together with the name of the borrower, date borrowed and
date returned, the condition on return
• any regular maintenance, such as safety checks.
Maintaining a knapsack sprayer
knapsack sprayer ►
A knapsack sprayer is a manual farm
machine used to spray pesticide mixtures
on to crops.
It consists of:
• a tank to hold the pesticide
• an adjustable lance with a pressure
relief valve to avoid spraying above
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 adjustable waist
band.
holders
control
handle
)s
Figure 9.22 A knapsack sprayer and
its parts.
138
9 Land preparation
Practical activities:
1. Clean and maintain some
simple tools.
2. Clean and maintain a knapsack
sprayer.
To use the equipment, chemicals are poured into the tank and the tank cover
is screwed on securely. Air is pumped into the sprayer tank, using the built-in
pumping device. The nozzle cap is adjusted to give the desired size of droplets. The
sprayer can then be used to spray the crop thoroughly. It is best to avoid spraying
on a very windy day and protective clothing should always be worn.
After spraying, the following procedures should be carried out:
• the residual air pressure should be released from the sprayer tank using the air
pressure release valve
• any unwanted chemical mixture should be emptied out of the tank and
disposed of in a hole in the ground
• the sprayer tank should be washed out with detergent
• the filter should be checked for any chemical particles which 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
• the sprayer and chemicals should be stored in a cool, well-secured area.
9.8 Safety precautions when operating tools,
machinery and equipment
In agriculture, safety practices are very important in the handling of 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 hazardous.
The following safety practices should be followed:
• ensure 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
• focus on the task while operating the equipment; stop if 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.
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: coveralls which 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, disposable
• safety glasses, goggles
• respirators and face masks: offer protection from fumes, smoke and dust
• ear-muffs: protection from loud noises.
139
Section B: Crop Production
safety devices ► Machinery and equipment may be fitted with safety devices such as:
• safety clips, buttons, bars
• shields, guards, filters
• safety fuses
• colour-coded lights
• an automatic shut-off which stops the equipment if there is a malfunction.
Safety and tractor operations
The tractor and its attachments should be in good condition. Any attachment must
be safely hitched with protective shields and safety guards in place. The driver
needs to be trained and wearing appropriate clothing (hard hat, steel-tipped
boots, no dangling clothing, straps or belts). He should adjust the seat so that it
is comfortable and all controls can be reached easily, and make sure that the rear
view minor is also adjusted. It is important to be aware of slippery areas, slopes,
proximity to services (gas, electricity and water mains), farm animals, children and
pets. When the operation has been carried out, the engine should be switched off
and the hand brake applied before adjusting or removing any attachments.
Figure 9.23 Safety gear worn by
someone using a knapsack sprayer.
rri
Distinguish between safety gear and safety
devices.
rrc
How should fuels and chemicals be stored on the
farm?
Handling fuels and chemicals
Most fuels used on the farm are combustible and care has to be taken when they
are handled, used and stored. Gasoline, dieseline 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 'no naked flame' 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 room. Protective clothing should be worn when these
chemicals are being used and all containers need to be thoroughly washed after
use.
Summar
Figure 9.24 Storage tanks for fuels
and compressed gas.
140
• Caribbean countries have a tropical marine climate with warm temperatures all
year round.
• There is a rainy season (May to October) and the rest of the year is relatively
dry. Hurricanes occur during the period from June to November.
• Because of the warm climate, plants grow well and seeds germinate rapidly.
• Rainfall affects agricultural production: in the rainy season there is leaching of
nutrients from the soil and flooding.
• In the dry season, some crops need to be irrigated.
• Weather forecasts help farmers to determine the best times for certain farm
operations, such as land preparation and harvesting.
• Rainfall is measured by a rain gauge, set up away from buildings and trees.
• Temperature is measured using a thermometer. It is usual to record the
maximum and minimum temperatures each day, using special thermometers.
• Over the Caribbean region, cold and warm fronts occur when the polar air
mass meets the tropical maritime air mass.
• A cold front causes the warm air to rise, clouds are formed and there is rain.
• The Intertropical Convergence Zone is formed by the North East Trades air
stream meeting the South East Trades air stream. The movement of this zone
causes the wet and dry seasons in the Caribbean.
• Studying weather records and weather patterns can be helpful to farmers.
• Land preparation is essential in ensuring that the soil is prepared for growing
crops.
• The first operation is to clear the land of trees, shrubs, grasses and crop residues.
9 •
•
•
•
•
•
•
•
•
•
•
•
•
Land preparation
Tillage involves ploughing the soil to break up the surface, to incorporate
organic matter and to prepare a good tilth for the planting of crops.
Tillage can be done manually or mechanically using a tractor and attachments.
Before crops are sown, the land may need to be fertilised and limed. Drainage
has to be provided to cope with excess water during the rainy season.
The land is levelled and beds are formed. The beds are designed to suit the
terrain and cope with the climate. Cambered beds are used in the rainy season,
so that the ground does not become waterlogged.
Many different types of machinery are now used in farming and make the
preparation of land and other tasks easier for the farmer.
Tractors, with their attachments, speed up tasks that were previously timeconsuming. There are different sizes of tractors, some with wheels and others
with metal chain belts that give grip on sloping terrain.
Other specialised equipment has been designed to harvest crops, sow seeds,
spray fertilisers and pesticides, cut grass and weeds and spread manure.
All tools, machinery and equipment need to be cleaned and maintained. Tools
are stored in racks, shelves and cupboards.
Everyone needs to be aware of the safety precautions when using tools and
equipment. Safety clothing and goggles should be worn when operating
machinery or spraying chemicals.
Safety devices on machinery should be in place and checked regularly.
Gasoline and kerosene should be stored in the correct containers. There should
be no smoking and no naked flames where these fuels are kept.
Chemicals used on the farm should be stored safely and equipment washed
after use.
ITCH
A tropical marine climate has warm temperatures all year round; it is
typical of islands in the equatorial regions; average temperature is 27°C.
ITQ2 In order to be able to plan the farm operations; so that spraying is not
done on windy days; land preparation and harvesting are not done when
there is likely to be heavy rain.
1103 There could be run-off from tall buildings and splashing from trees; both
affect the quantity of rain getting into the funnel of the rain gauge.
IT04 A maximum thermometer is filled with mercury and records the
maximum temperature reached in the day. A minimum thermometer is
filled with alcohol and records the lowest temperature.
11115
To keep them screened from the sun, from air movements and from
conduction of heat from the ground.
IT06 Weather information can be obtained from the radio, television and
internet.
ITU When the polar air mass meets the tropical maritime air mass, there is a
cold front at the edge of the polar air and a warm front at the edge of the
tropical air. The warm air rises and rain clouds form.
ITQ8 Leaching of nutrients from the soil and flooding of the land, so that crops
are destroyed and work on the fields is impossible.
ITQ9 Trees can be removed using an axe or chain saw and a bulldozer.
IT(11 0 These can be removed using a weed wacker or a brushcutter attached to a
tractor.
ITIll 1 Tillage is the breaking up of the soil and the incorporation of organic
matter.
11012 Primary tillage involves ploughing the land to break up the soil surface.
Secondary tillage is breaking up large clods of soil into smaller aggregates.
141
Section B: Crop Production
11013 It is better to use manual methods on small farms and where the terrain
is hilly or mountainous.
11014 Levelling is done when land is prepared for the crop so that lumps are
removed and there is a flat surface on which to plant seeds and seedlings.
11015 Machines speed up operations on the farm, more land can be cultivated,
and more work can be done each day. More food can be produced.
11016 A four-wheeled medium tractor with attachments.
11017 The mechanical seeder can be adjusted to give the right sowing density,
the seeds are sown more evenly and the job does not take as long.
11018 A disc plough.
11019 To cut up and incorporate organic matter into the soil, to break up heaps
of manure, and to produce a good tilth during secondary tillage.
ITQ20 Tools should be stored in a special area, on racks, on shelves or in
cupboards.
11021 Wipe them over with an oily rag and keep them in a dry place.
11022 Safety gear refers to clothing, face masks, goggles and ear muffs that are
worn by the operators of machinery. Safety devices are clips guards and
filters that are fitted to machinery and equipment to protect the operator.
11023 Fuel and chemicals should be stored in locked stores. There should be no
smoking or naked lights near fuel stores.
Examination-style
questions
Multiple Choice Questions
1. The best attachment to use to break up a hardpan is a:
A mouldboard plough
B disc plough
C chisel plough
D rotovator
2. A face mask should be worn when operating a:
A crop sprayer
B manure spreader
C fertiliser spreader
D harrow
3. The Intertropical Convergence Zone is formed when:
A the polar air mass meets the tropical maritime air mass
B the polar air mass meets the North East Trades
C the South East Trades meet the tropical maritime air mass
D the North East Trades meet the South East Trades
4. 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
Structured and essay-style questions
1. (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.
142
9 • Land preparation
2. (a) (i) List FOUR types of plough drawn by the farm tractor.
(ii) State the main uses of each of the ploughs named in (a)(i).
(b) Farmer Rose is planning to plough a plot of land (comprised of 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.
3. (a) Naming 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:
(ii) rotovator
(i) brushcutter
(iii) harrow
(iv) trailer
4. (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.
5. (a) Name hand tools and equipment best suited for the following
agricultural operations:
(i) tillage
(ii) pruning
(iii) harvesting.
(b) State the safety practices which should be followed when using
agricultural tools and equipment.
(c) List the practices necessary for the maintenance of agricultural tools
and equipment.
6. (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 which should be followed in
handling such fuels on the farm.
7. 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.
8. Give an account of the climatic factors which influence crop production
in the Caribbean.
143
IIIIIIIIIIIIOII
// 11/ /rununmu..........
Plant for ppolo 9V an.d
physiokgy
By the end of
3
this chapter
i
describe the functions of the plant structures identified
you should be
/
explain the processes of sexual and asexual reproduction in plants
able to:
3
distinguish between natural and artificial asexual reproduction
3
relate reproduction in plants to crop production
3
describe the conditions needed for the germination of seeds and the
describe the external and internal structure of plants
growth of seedlings
3
explain the roles of photosynthesis, respiration, transpiration,
absorption, translocation, photoperiodism and phototropism in the life
of plants
3
discuss the effects of environmental factors on plant growth and
development.
Concept map
Plant morphology and physiology
Structure and
functions of
plants
Sexual
reproduction in
plants
and dicots:
seeds
Parts of a
flower
stem
root
leaf
Pollination
Fertilisation
Seed formation
144
Asexual
reproduction
rhizome
sucker
corm
bulb
tuber
runner
stolon
budding
grafting
tissue culture
layering
stem cutting
root cutting
Crop
production
Sexual and
asexual
reproduction:
Advantages
Disadvantages
Germination
of seeds
Plant
processes
hypogeal
epigeal
Transpiration
light
water
temperature
Translocation
Sowing seeds
and care of
seedlings
Effect of environmental factors on
crop production
10 • Plant morphology and physiology
10.1 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
(carrots), flowers (cauliflowers), fruits (bananas) and seeds (coffee).
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 ►
Plants may be classified according to their major group, family, life cycle or growth
habit.
• Major group: seed plants, sometimes referred to as flowering plants, 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, e.g. peas and beans belong to
the family Leguminoseae.
• 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, such as
lettuce, peas, corn, tomatoes); some take two growing seasons or two years
(biennials, such as carrot, celery, radish, beetroot); others continue to grow,
flower and produce seeds for many years (these are the perennials, such as
citrus, mango, cocoa, 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 and mahogany).
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 10.1.
Monocots
Seeds have one cotyledon (seed leaf)
and an embryo.
Fibrous root systems.
Stems with scattered vascular bundles.
Usually no cambium present in stem or
root.
Long thin leaves with parallel veins
Name ONE example of a monocot plant and ONE
example of a dicot plant.
Flower parts in threes, e.g. 3 petals,
3 stamens; grass flowers lack brightly
coloured petals or sepals.
Mainly herbs and grasses, with few
trees,
Dicots
Seeds have two cotyledons and an
111
embryo.
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. 5 petals, 5 stamens;
obvious petals and sepals, often brightly
coloured.
Herbs, shrubs and trees, e.g. cabbage,
cotton, citrus.
' e.g. corn, rice, sugar cane, bamboo.
How do the flowers of monocots differ from the
flowers of dicots?
Table 10.1
The major characteristics of monocots and dicots.
145
Section B: Crop Production
single spikelet
lI
7
er
s
etals
whole tomato plant
whole grass plant
Figure 10.1 A grass plant (monocot) and a tomato plant (dicot).
Plant structure
flower:
contains reproductive parts
flower bud
leaf:
takes in carbon dioxide;
absorbs light for
photosynthesis
^^
I
stem:
supports leaves and flowers;
transports water and minerals
1
r root
branches
,.. .
4
shoot
system
bud
main root
root system:
provides anchorage
takes up water
takes up minerals
Figure 10.2 The external structure of a typical flowering plant.
Figure 10.2 shows that the root system is below the ground and the shoot system is
above ground. The root system provides anchorage and takes up water and mineral
r 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.
146
10 - Plant morphology and physiology
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 (e.g. tomato, mango)
• fibrous roots consist of a cluster of roots growing from the base of the stem
(e.g. coconut palm, corn)
• adventitious roots grow from the base of stem cuttings (e.g. croton) or from
leaves (e.g. Bryophyllum)
• aerial roots grow above ground (e.g. Ficus, Philodendron).
Practical activity:
Make drawings of different types
of root systems.
aerial
roots
1
List the main types of roots.
adventitious
epidermis
Figure 10.3 Main types of roots. Tap root systems are typical of dicots; fibrous
cortex
root systems are found in monocots.
endodermis
cambium
phloem
xylem
pericycle
Figure 10.4 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:
Make drawings of a transverse
section through a young root and
label all the parts.
What are the functions of the xylem and phloem
in a root?
Dicot roots
The internal structure of a young dicot root is made up of four types of tissues:
• epidermis: a single layer of cells on the outside of the root; cells in young roots
have outgrowths forming root hairs; function is to protect the young root and
to absorb water and mineral ions
• cortex: many unspecialised thin-walled cells, called parenchyma tissue; forms
the bulk of the young root; the cells have spaces between them (intercellular
spaces)
• endodermis: a single layer of cells separating cortex from vascular tissue; the
cells control movement of soluble materials between cortex and vascular tissue
• vascular tissue: a cylinder at the centre of the root.
The vascular tissue is made up of several different types of cells (see Table 10.2).
Tissue
Location in root
Functions
lir
Xylem ► In centre of root; can be
Transport of water and mineral ions
from soil to aerial parts of the plant.
Phloem ►
Transport of soluble food substances
from where they are made in leaves to
the roots.
Gives rise to branch roots and the
cambium tissue which can produce
more vascular tissue and the outer
corky layer on older roots.
Pericycle ►
star-shaped.
Groups of cells found
between the projecting
parts of the xylem.
Single narrow layer of cells
just inside the endodermis.
What is the pericycle and what is its function?
147
Section B: Crop Production
Stems
herbaceous stems ►
woody stems ►
epidermis
vascular bundle
phloem
Stems can be soft and non-woody (herbaceous) or woody. Herbaceous stems are
often green and carry out photosynthesis, but woody stems are covered in a layer
of bark which is waterproof. Monocots have non-woody stems, but dicot trees
and shrubs have woody stems. The stems of most plants grow upright, but some
have underground stems called rhizomes. Cacti have stems which are modified for
storage of water.
Dicot stem
cambium
A dicot stem is made up of the same tissues as the root, but they are arranged
differently:
• the epidermis has stomata (openings through which exchange of gases occurs
during respiration and photosynthesis)
• there is no definite endodermis
• vascular tissue is in separate bundles arranged in a circle around a central
region of cells forming the pith
• cambium tissue is located between the xylem and the phloem in each vascular
bundle.
xylem
cortex
Figure 10.5 The internal structure
(transverse section) of a young dicot
stem.
t.
How does the arrangement of tissues in a stem
differ from that in a root?
Monocot stem
It
Distinguish between herbaceous and wood y
stems.
1'_
Practical activity:
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
• there is usually no cambium between the xylem and phloem in the vascular
bundles.
Leaves
Make drawings of transverse
A typical leaf consists of:
• a leaf blade, or lamina, which is the flat part
• a leaf stalk, or petiole, which attaches the leaf to the stem
• a midrib, or main vein, consisting of the transporting tissues
• a network of smaller veins.
sections through young monocot
stems and dicot stems.
simple leaves ►
compound leaves
►
,bes
The tip of the leaf is called the apex. The edges of the leaf are referred to as the
margin.
The leaves of monocots (e.g. 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 have a leaf blade that is not divided, but 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 either side of the midrib (pinnate).
Examples are shown in Figure 10.7.
crib
:iole
monocot leaf
Figure 10.6 The external features of
a typical leaf.
148
pinnate leaf
Figure 10.7 Types of leaf.
simple dicot leaf
palmate leaf
10 • Plant morphology and physiology
What are the external differences between
monocot and dicot leaves?
Type of
tissue
Epidermis
Mesophyll
Vascular
tissue
Leaves may be modified for food storage (fleshy leaf bases in 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 10.3).
Position in leaf and characteristics
Functions
• Upper epidermis: single layer of cells covering upper
surface; layer covered by waxy cuticle; contains fewer
stomata than the lower epidermis.
• Lower epidermis: single layer of cells covering lower
surface; contains more stomata than the upper epidermis.
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; cells are elongated, at right angles
to the upper epidermis and packed tightly; contain large
numbers of chloroplasts
• Spongy mesophyll in the lower part of the leaf; cells are
irregularly-shaped with large air spaces between; contain
fewer chloroplasts than palisade cells.
Vascular tissue is linked with vascular tissue in the stem;
present in the main vein and the network of smaller veins;
composed of xylem and phloem.
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 absorb 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.
The xylem transports water and mineral ions
to the leaf; phloem transports sugars from the
leaves to other parts of the plant; the xylem
in the midrib and leaf veins supports the leaf
tissues.
4iilit
Table 10.3 The internal tissues of a leaf, their characteristic features and functions.
Cell wall
cuticle
•
-
_rrt e? , 0N 000 000 0000 000
og
(:) 0
o 0 n
0
o
0 0
0 0°
ot 0 0 o
o
0
OO
O
palisade cells--
upper epidermis
0
•
O
0
o 0
° 2,o p 0
•
00
°
No 0.90
0
O
o
O
0 .
0 0 oo °
0 , 0 o to, .)(.? 0,
000
xylem vessel
0 0
phloem
air space saturated with water vapour
mesophyll cells
- moist cell wall
What are the functions of the epidermis of the
leaf?
r
Practical activity:
Make drawings of leaves of
monocots and dicots to show their
internal and external structures.
C
10
Hlower epidermis
stoma
guard cell
(gap between
the guard cells)
Figure 10.8 The internal structure of a dicot leaf.
The arrangement of the tissues in a monocot leaf (e.g. grasses) differs from that in
a dicot leaf:
• there is no palisade mesophyll
• there is less distinction between upper and lower epidermis
• there is no definite midrib.
149
Section B: Crop Production
Seeds
embryo ► A seed contains the embryo which will develop into a young plant. It also contains
testa ► a store of food for the embryo. A seed is surrounded by the seed coat or testa.
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
• the 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.
cotyledons ► If the testa is removed, you can see two cotyledons, or seed leaves. The embryo
radicle, plumule ► 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 10.9.
b) The testa removed
a) External appearance
of a broad bean seed
seed leaves
(cotyledons)
contain food store
seed coat
or testa
tiny hole
(micropyle)
where water
enters before
germination
scar where
seed was
attached
to pod
plumule
(embryo shoot)
embryo
radicle
(embryo root)
Figure 10.9 Internal and external structure of a dicot seed (broad bean).
Monocot seed
A monocot seed, such as the maize grain in Figure 10.10, differs from the broad
bean seed:
i
s
Name THREE features that can be seen on the
outside of a bean seed.
• the outer protective coat is formed from 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.
A whole maize grain
Section through a maize grain
1
State where the food is stored in a maize seed
and in a bean seed.
Practical activity:
Investigate the external and
internal structure of monocot and
fruit wall
fruit wall
food store
position of cotyledon
plumule
embryo
radicle
position of embryo
cotyledon
point of attachment
to cob
dicot seeds. Make drawings and
write notes about the differences
kil
that you find.
r^ l
Ic l
Note that the maize grain is a one-seeded fruit; the testa and fruit wall are fused
Figure 10.10 Internal and external structure of a monocot seed (maize grain).
150
1 0 - Plant morphology and physiology
10.2 Sexual and asexual reproduction in plants
Sexual reproduction
The flowers of seed plants contain the organs of sexual reproduction. Most
flowers, such as guava, contain both male and female parts in one flower and are
hermaphrodite ► called hermaphrodite. But other plants, such as pumpkins, produce separate male
flowers and female flowers on the same plant.
Parts of a flower
receptacle ►
calyx ►
►
stamens ►
anthers ►
carpels ►
stigma ►
corolla
A typical flower has the following parts:
• a flower stalk, or pedicel: attaches the flower to the stem
• a receptacle: the swollen tip of the pedicel to which all the other floral parts
are attached
• a whorl (ring) of sepals, called the calyx: often green; protects the other flower
parts when in a bud
• a whorl of petals, called the corolla: usually brightly coloured to attract
pollinating insects
• the male parts of the flower, called stamens: each consists of a filament, or
stalk, bearing anthers in which the pollen grains containing the male gametes
are formed
• the female parts of the flower, called carpels: each consists of a receptive
surface, the stigma, attached to the ovary by the style; the ovary contains
ovules in which are the female gametes, or egg cells.
Male flowers have all the above parts except the carpels. Female flowers lack
stamens.
petal
stigma and style
ovule
carpel
nectar)/
sepal
anther !
filament I
stamen
receptacle
flower stalk
Name the parts of the flower concerned with the
production of the male gametes.
What is the function of the style?
►
self-pollination ►
cross-pollination ►
pollination
Figure 10.11 The parts of a typical flower (this flower has both male and female
parts).
The ovules, which are the potential seeds, are inside the ovary. 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. The pollen may
be transferred from the anthers to the stigma of the same flower or to another
flower on the same plant; this is known as self-pollination. Or pollen may be
transferred from the anthers of one flower to the stigma of another flower on a
different plant of the same species; this is known as cross-pollination.
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
151
Section B: Crop Production
t •
Write a definition of pollination.
r
Name THREE agents which can bring about
pollination.
t
-
Why is the pollen of wind-pollinated flowers light
and smooth?
Practical activity:
Look at some pollen from a windpollinated flower and some pollen
from an insect-pollinated flower.
Make notes on the differences
that you observe.
vigour of a species and to produce plants which 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 brought about by birds, other small animals and humans,
but the main agents are wind and insects. Wind-pollinated flowers and insectpollinated flowers show adaptations to their mode of pollination (see Table 10.4).
Wind-pollinated flowers
owers are often small; petals and
pals may be absent; no scent
o 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: grass
cerea
Insect-po inated 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 10.4 A comparison of wind-pollinated and insect-pollinated flowers.
Fertilisation
fertilisation ►
Fertilisation is the fusion (joining) of a male gamete with a female gamete to form a
zygote, which 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
seed formation ►
Describe what happens during fertilisation.
After fertilisation, seed formation occurs. The fertilised egg develops into the
embryo of the new plant. Food, made by 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 bean and maize, food is not stored in the cotyledons, but remains as a
separate tissue. The tissues which surrounded the ovule in the ovary become the
seed coat.
Asexual reproduction
asexual reproduction ► Asexual reproduction refers to the propagation of plants by means of vegetative
parts and does not involve gametes. Asexual reproduction can be achieved by
natural methods, e.g. tubers, suckers and rhizomes, or artificially by cuttings,
budding, grafting and tissue culture.
Natural methods of asexual reproduction
Several crops produce vegetative parts (see Figure 10.12) 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 ► 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 10.5). Many of the plant parts used in natural vegetative
propagation are also eaten by humans and other animals (e.g. potato tubers).
152
10 Plant morphology and physiology
root tuber.
e.g. sweet pota
sucker
Corm
banana
rhizome, e.g. ginger
stolon, e.g. grasses
runner
Figure 10.12 Examples of vegetative organs.
Vegetative
organs
sucker
tuber
rhizome
Corm
bulb
stolon
rtuw
Name FIVE natural methods of plant propagation.
runner
Define asexual reproduction.
Table 10.5
Description
Example
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.
• 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.
cassava: does not sprout)
• ginger; saffron; canna lily;
ginger lily
• eddo; tannia; dasheen
• onion; lily
• Bahama grass; nut grass
• strawberry; savanna grass;
pumpkin
Some organs of perennation.
153
Section B: Crop Production
Artificial propagation
The main methods of artificial propagation are:
• cuttings, e.g. cocoa, guava
• layering, e.g. rose, lime
• budding, e.g. orange, avocado
• grafting, e.g. mango
• tissue culture, e.g. orchid, banana.
stem cuttings ►
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.
Types of stem cuttings (pieces of stem from which new plants will grow) are
listed in Table 10.6.
Type of cutting
Hardwood; taken from
mature plants with
bark.
Semi-hardwood; taken
where bark is not fully
developed,
Softwood or
herbaceous; taken
from new (nonwoody) growth.
Figure 10.13 A plant propagation
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 10.6 Types of stem cuttings.
bin.
iti
Name THREE crop plants that can be propagated
by means of stem cuttings.
root cuttings ►
Stem cuttings are usually taken from plants early in the morning, when plant
cells are turgid (full of water), 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, the leaves removed or partially trimmed if necessary, and the
base dipped into a rooting hormone which encourages growth of roots. The soil is
watered and the propagator 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 will grow. They are taken
when parent plants are not actively growing, just before the rainy season. 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.
Layering
adventitious roots ► In layering, a young branch of a parent plant is encouraged to produce adventitious
tongue layering ►
154
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
are roots which form from a section of the plant which 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.
10 • Plant morphology and physiology
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)
parent plant
peg holds branch
at soil level
b)
- the pegged area is
covered with humus
and kept moist; the
stem can be cut from
the parent plant when
the roots are established
roots develop
small cut made
at node
Figure 10.14 Tongue layering.
air layering ►
What is the difference between tongue layering
and air layering?
1
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.
1
•
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.
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.
c)
a)
T-shaped
cut made
in rootstock
d)
tape
bud cut from one
plant (scion)
bud (scion) inserted
into rootstock
bud and stock
surrounded with tape
Figure 10.15 Budding.
155
14
Section B: Crop Production
Grafting
grafting ► 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 in the propagation of mango, avocado and sapodilla.
The two types of grafting are:
• 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 taped securely 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.
a)
c)
b)
a top graft:
notch cut in
rootstock
IrJ
Explain the difference between the stock and the
scion.
scion: to be cut
with a tapered
end
tapered end of
scion inserted
into rootstock:
bound together
with tape
Irc
Name THREE plants that are propagated by
grafting.
Figure 10.16 Top grafting.
Tissue culture
tissue culture ► Tissue culture is an artificial method of plant propagation in which a piece of plant
tissue, such as stem, leaf or root, is cultured in a growing medium consisting of
agar, nutrients and plant hormones to produce new plants. The technique requires
sterile, controlled conditions and can result in large numbers of identical plants,
called clones. Orchid, banana and pineapple plants can be mass produced in this
way.
10.3 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 of our leaf and root vegetables are raised from seed. In the past, the farmer
would allow some of his 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 (e.g. fruit trees) takes a long time and the plants that
result 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.
156
10 •
Plant morphology and physiology
Some plants, such as banana, pineapple and breadfruit, do not produce viable
seeds — these are often propagated artificially (see Table 10.7).
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.
• Can propagate plants that do not produce viable seeds.
• Budding and grafting of scions on to dwarf stocks 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.
• Risk of total crop loss through disease is greater than with
seeds.
• Some of the techniques involved in artificial propagation
require skills which may not readily be available, e.g.
budding, grafting.
• Techniques such as tissue culture are expensive to set up
and are only economical if very large numbers of plants
are produced.
-
Table 10.7 Advantages and disadvantages of asexual reproduction in crop plants.
ITQ24
What are the advantages of vegetative
propagation?
The rhizomes of ginger, saffron and arrowroot can be cut into sections and, provided
that each section has at least one lateral bud, new plants can result. Bulbs, such
as onions and garlic, produce offset bulbs which 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 which produce shoots.
10.4 Seed germination
viable seed ►
What is meant by the term percentage
germination?
List the conditions needed for the storage of
seeds.
germination ►
Practical activity:
Carry out germination tests on
different types of seeds, e.g.
seeds kept in sealed containers
and seeds that have not been kept
in sealed containers; or seeds that
are old and much younger seeds.
A viable seed is one which 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 percentage germination, 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, air containing
oxygen and a suitable temperature (see Table 10.8). In addition, most seeds
germinate more readily in darkness (although some 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
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.
Causes the seeds to swell, splitting the testa and allowing
cells to take up water; enzymes are activated so that starch
is 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 10.8 The main conditions needed for germination.
157
Section B: Crop Production
scarification ►
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 different techniques,
including scratching seed coats with a sharp and pointed instrument, blowing
seeds against a rough surface or rubbing the seeds on sandpaper.
Epigeal and hypogeal germination
epigeal germination ►
hypogeal germination ►
i
Name the THREE main conditions needed for
germination to occur.
r
Why do some seeds need to be scarified before
sowing?
01
i
I
There are two main types of germination:
cotyledons
epigeal germination and hypogeal
germination. In epigeal germination, the
cotyledons come above the ground as the
plumule
seedling grows; in hypogeal germination,
(develops into the shoot)
the cotyledons remain below the ground.
radicle
(develops into the root)
To understand the differences, look at
the embryo in Figure 10.17. Identify the
epicotyl, the region between the plumule
and the cotyledons; then identify the Figure 10.17 An embryo plant.
hypocotyl, the region between the radicle
and cotyledons. The two types of germination are compared in Table 10.9.
Epigeal germination
The radicle emerges and grows into the
soil.
The hypocotyl elongates forming an
arch.
The arched area appears above the
ground.
The hypocotyl straightens bringing
the cotyledons above the ground; the
plumule is protected between the
cotyledons.
The plumule grows, forming the first
set of leaves,
The cotyledons wither and eventually
fall off.
Examples: kidney bean, cashew nut,
L tomato, cabbage.
Hypogeal germination
The radicle emerges and grows into the
soil.
The epicotyl elongates forming an arch.
The arched area appears above the
ground.
The epicotyl straightens bringing the
plumule above the ground; the plumule
is pulled backwards through the soil so
the leaves are not damaged.
The plumule grows forming the first
true leaves.
The cotyledons remain below the
ground.
Examples: maize, pigeon pea, broad
bean.
Table 10.9 Epigeal and hypogeal germination compared.
true leaves
epigeal germination
plumule
hypogeal germination
coleoptile
fl
cotyledon
remains below
ground N
coleorhiza
^coleorhiza
radicle emerges and
grows into the soil
the coleoptile (plumule
sheath) grows uprightly
plumule emerges from
the coleoptile
plumule grows
vigorously
above the ground
Figure 10.18 Epigeal germination in kidney bean (left) and hypogeal
germination in maize (right).
158
10 • Plant morphology and physiology
What are the differences between epigeal and
hypogeal germination?
Describe the germination of a monocot seed such
as maize.
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.
Sowing seeds and seedling production
Practical activity:
Plant some seeds and grow
In crop farming, seedlings are produced using two major systems: container
systems and seedbed systems.
seedlings under different
Container systems
conditions. For example, grow
Various containers can be used to raise seedlings: seedboxes, Speedling trays, plastic
bags, plastic cups, discarded cans and plastic bottles. For large-scale production
of seedlings in containers, it is usual to use seedboxes or Speedling trays. Any
containers should be provided with holes for drainage before being filled with a
potting soil mixture. Commercially produced potting soil mixtures, such as Promix
( made up of peat moss, perlite, vermiculite and dolomitic limestone) can be
purchased. 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
• 30 cm 3 of soil insecticide (Diazinon) and 10 g of fungicide per 4.5 litres of
water.
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 and well-aerated, retains adequate moisture and will drain freely. The
addition of insecticide and fungicide, together with the sterilisation, will ensure
that it is free from pests and weeds. Ideally, the mixture should have a pH of 6.0
to 6.5.
Seedboxes, otherwise known as nursery boxes, are used for sowing seeds,
pricking-off (thinning out) seedlings and raising young crop plants.
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.
seedboxes ►
95D
nails
cm
41 1
pA I
4,
I I 11 1
slits for drainage
cm
laths 1 cm thick
Figure 10.19 A typical seedbox.
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. A box this size can accommodate 35 seedlings. It is light to handle and
can be re-used for several batches of seedlings. Before sowing seeds, a thin layer
of straw should be placed on the base to prevent potting soil from falling through.
Sifted potting soil is placed in the box to a height of I cm from the top, levelled off,
firmed with a pressboard and then watered.
159
Section B: Crop Production
Speedling trays ► Speedling 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 and 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.
o
MYp
o00
000
0000,
0000
ioo
O ooOooo000
0 0Co)o0000
0 0 0 0o styrotex
O O O O O O O O C) O C) C)
plastic
00000
^0^00
Figure 10.20 Speedling trays.
The advantages of container systems are that:
• the seedlings are cared for in a nursery
List THREE types of containers that can be used
for planting seeds.
r
+
What are the advantages of using Speedling
trays?
• it is more convenient to handle and transport the seedlings
• the seedlings become well-rooted in the potting soil medium
• 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.
Seedbeds
Practical activity:
Produce some seedlings for sale.
Seedbeds are useful for the production of seedlings for field crops, such as ri ce,
cabbage, tomato and sweet pepper, requiring a large number of plants. 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.
When preparing a seedbed:
• the area should be brushcut and
cleared of grass and bush
• plough with a hand tractor or garden
fork
A►^iir r
^
seedling compa rt ments
seedling compartments
r
Why is a seedbed established close to the field
plot?
List TWO features of a typical seedbed.
160
• refine the soil to a fine tilth using a
rotovator, hoe or rake
Figure 10.21 A typical seedbed.
• 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 (30g/m2)
• mix manure and fertiliser with the top 4 to 8 cm of soil
• level the soil and remove large pieces of organic matter with a rake
• apply a mixture of insecticide and fungicide.
10 • Plant morn - l ogy and physiology
1. H
2. Plough
,Iv m.
3. Refine soil to a fine tilth
4. Dig box drains and camber beds
5. Manure !hr
6. Rakc manure
7. Level surface to remove large pieces of organic 8. Spray bed with insecticides and fungicides
matter
Figure 10.22 Stages in the preparation of a seedbed.
Methods of sowing seeds
List FOUR methods of sowing seeds in a nursery.
Explain how very tiny seeds, such as tobacco,
should be sown.
1
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, getting the distribution as even
as possible. They are then covered with a thin layer of potting soil or Promix.
• Seeds may be sown in shallow drills made by a dibber in the soil surface.
A thin layer of potting soil or Promix is used to cover them.
• 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 Speedling 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 or Promix.
161
Section B: Crop Production
3.
2. Sowing in drills
1. Broadcasting
4.
Mixing in water
Sowing singly in containers
Figure 10.23 Methods of sowing seeds.
The 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,
transparent polythene roof
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, Speedling trays
and containers.
nursery ►
mist spray
sturdy materials
Thinning-out
seedling trays
hardening seedlings
concrete floor
metal or concrete stand
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.
Figure 10.24 A typ'cal nursery
environment.
■%s.
1 01°°
1. water soil in seedbox
1 1 1 1 1 0"
11111
2. make holes with the dibber
3. carefully select a seedling
.... /
4. gently position soil around
the roots
5. water the seedlings
Figure 10.25 Pricking-off or thinning-out seedlings.
162
6. place under the shade of a tree
10 - Plant morphology and physiology
Looking after seedlings
I
Why should the roof of a nursery be transparent?
I
Give TWO reasons for thinning out seedlings.
I
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 at regular intervals
and treated with insecticides if necessary. Seedlings may be attacked by a fungus
that causes a disease called 'damping off', where the stems are weakened and
topple over. The disease can be controlled by aerating the soil, controlling the
watering and applying a fungicide to seedlings and soil twice weekly.
Transplanting
transplanting ► Before transplanting, seedlings should be gradually exposed to sunlight over a
hardening ► 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 scorching sun
• reduce the wilting which may occur at transplanting time.
The field plot is prepared by digging holes for the seedlings, using the recommended
spacing, and placing pen or compost manure 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 it stays upright. Seedlings
should be watered after transplanting: this reduces wilting and settles the loose
soil, bringing soil particles in closer contact with roots.
rV
What is the purpose of hardening seedlings?
1.1
At what time of day should seedlings be
transplanted and why?
Figure 10.26 Transplanting seedlings.
Stages of plant growth
vegetative stage ►
During the life of a plant, there are two main stages of growth: the vegetative stage
and the reproductive stage.
The vegetative stage involves:
• growth of the zygote into the embryo, the embryo into the seedling, and the
seedling into a mature plant
• rapid increase in cell division, cell enlargement and differentiation into
specialised tissues and functions
163
Section B: Crop Production
• rapid increase in plant size and weight
• much branching and leaf development.
reproductive stage ►
In the reproductive stage:
• the general increase in plant size slows down and 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 10.27.
maturity
vegetative stage
zygote
embryo
seedling
young immature mature plant
plant
reproductive stage
flowering stage
and seed
production
dead plant
Figure 10.27 The stages of plant growth.
10.5 Plant processes
Photosynthesis
photosynthesis ► Photosynthesis is the process by which plants manufacture carbohydrates
11041
Write down a word equation for the process of
photosynthesis.
1
Why does light intensity affect the rate of
photosynthesis?
Practical activity:
R
F
Carry out a simple experiment
to show that light is necessary
for photosynthesis. You can use
a water plant and collect the
oxygen given off as a product of
photosynthesis.
(sugars and starches) in their leaves, using carbon dioxide from the air and
water from the soil, in the presence of the green pigment chlorophyll and under
the influence of light.
The chemical and word equations which summarise photosynthesis are given
below.
CH1206 + 602
61-120 + 6CO 2—■
Chemical equation:
water + carbon dioxide —+ glucose (carbohydrate) + oxygen
Word equation:
Photosynthesis is affected by: carbon dioxide concentration, light intensity,
temperature and soil water supply.
The sugars manufactured during photosynthesis are used by the plant in the
following ways:
• in the process of respiration to release energy for cell division and growth
• to form starch, which is stored in leaves and other storage organs, such as
tubers and seeds
• in the manufacture of proteins and lipids which are essential for the formation
of cells so that the plant can grow in height and girth, developing stems, leaves
and reproductive structures.
Respiration
respiration ►
Respiration is the process by which sugar is oxidised or broken down, releasing
energy for growth and development. It is the opposite of photosynthesis:
photosynthesis involves building up molecules which store energy; respiration
involves breaking down molecules to release energy.
The chemical and word equations which summarise respiration are given below.
I
Chemical equation: C 6 1-1, 2 0 6 + 60 26CO2 + 611 2 0 + ENERGY
glucose + oxygen --■ carbon dioxide + water + ENERGY
Word equation:
164
10 Plant morphology and physiology
Energy is stored in molecules of adenosine t ri phosphate (ATP) which can be used
in the cells.
The energy released is essential for cellular activities such as:
the formation of new cells resulting in the growth of the plant
•
maintaining the activities of existing cells
• moving mate ri als throughout the plant.
r
Write a word equation for respiration.
t^y^r
Give reasons why plants need energy.
Transpiration
transpiration ►
stomata ►
Practical activity:
Carry out an experiment to
show that energy is given off by
respiring seeds. Use germinating
seeds, thermos flasks and
thermometers. Remember to set
up a control.
transpiration stream ►
What happens if transpiration exceeds the
absorption of water by a plant?
wilting ►
Practical activity:
Car ry out a simple experiment to
show that water vapour is lost
from the leaves of a plant. Use
cobalt chloride paper — this is blue
when dry and goes pink when it
is wet.
Transpiration is the process by which plants lose water in the form of water vapour
through stomata on their leaves and green stems. Stomata are small holes which
occur on the leaves or green stems.
Transpiration results from the uptake and transpo rt of water through the plant
from roots to leaves. The loss of water as water vapour 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, resulting in the ri gidity of leaves and soft stems
• it transpo rt s 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 roots, through the stem and up to the leaves. The
column is referred to as the transpiration stream. There is also a cooling effect on
the leaves as water evaporates from cells.
Wilting
If transpiration exceeds absorption of water by the plant and soil water is in short
supply, then cells lose their turgor and wilting occurs. 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 must get
rid of waste mate ri als. To get in or out of cells, all substances need to pass through
the cell membranes. Movement through cell membranes can occur passively by
diffusion, or actively in a process requi ri ng energy.
Absorption of water is essential for photosynthesis, respiration and translocation.
All these processes are inter-related and contribute to plant growth and
development. Any factor which hinders absorption of water will affect growth and
development. If plants cannot absorb sufficient water, then wilting occurs.
Diffusion
diffusion ► Diffusion occurs when molecules move from an area where they are in high
concentration to an area where their concentration is lower. Diffusion will
continue until the concentration everywhere is the same. No energy is required
for this to happen.
Osmosis
osmosis ► Osmosis is used to describe the diffusion of water across a pa rt ially permeable
membrane from a dilute solution (with a high concentration of water molecules)
to a more concentrated solution (with a 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 cell sap, so water
molecules pass from the soil solution into the root hair cells. This is an example of
osmosis taking place. Water then moves in a similar way across the cortex of the
root into the xylem vessels. The movement of water occurs along a concentration
gradient.
165
P1
SPctinn R.
Section B: Crop Production
Active transport
r-
Mineral ions are transported from the roots to other parts of plant and used by
the cells. Sometimes mineral ions enter the roots by diffusion. If there is a higher
Why does active transpo rt require energy?
concentration
of mineral ions in the soil solution than in the cell sap of the root
^
I
ii^
hair cells, ions will diffuse from the soil solution into the root hair cells.
How are mineral ions absorbed by plants)
However, if the concentration in the cell sap is higher than in the soil solution,
active transport ► ions may be taken up by active transport. This process requires energy to move the
ions against the concentration gradient.
Translocation
translocation ►
I
Practical activity:
To demonstrate osmosis in plant
tissue, cut square chips off a
potato tuber. Immerse some chips
in pure water and some in salt
solution. Leave them for an hour
and then obse rv e the changes.
Name the tissues which are specialised for
translocation in plants.
Translocation is the process by which water, mineral ions and food substances are
transported in specialised tissues within the plant.
The specialised tissues are:
• the xylem, composed of vessels and tracheids: transports water and mineral
ions
• the phloem, composed of sieve tubes and companion cells: transports food
substances in solution.
Translocation may take place upwards: water and mineral ions from the soil move
through the xylem to the leaves; or soluble food substances move from storage
organs to growing points, buds, flowers and fruits.
Food materials manufactured in leaves (sugars) are translocated downwards
to the lower parts of the plant and to storage organs. There is also some radial
(sideways) transport of water and food materials from the xylem and phloem to
surrounding tissues.
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.
Phototropism
phototropism ►
Practical activity:
To demonstrate the transport of
water in a plant, place a stick of
celery in a solution containing a
red dye; observe the movement of
the dye by cu tt ing sections across
the celery stalk at intervals.
light source
Phototropism is a growth movement
made by a plant in response to the
-direction of a light stimulus. If the tips
of plant shoots are exposed to a light
source, they will bend and grow towards
,
the light. This is an example of positive Figure 10.28 Positive phototropism
phototropism. It benefits the plant as it in seedlings.
places the leaves in the best position for
photosynthesis. Usually, plants respond
by bending their stems in the direction from which the light is greatest. This can l:
clearly seen if seedlings are kept for some time on a windowsill.
Photoperiodism
photoperiodism ►
Practical activity:
Place some small seedlings in
a box with a slit cut at one side.
Place a lid on the box. Leave for
24 hours and then observe the
seedlings.
11
1e5
Photoperiodism refers to the influence of day length (duration of light) on tl
production of flowers. In temperate countries, there is some variation in t
number of daylight hours due to the winter and summer seasons. In the trop
and the Caribbean, the variation in hours of daylight is not as great, but the eff
can still be seen in some plants.
Based on the effects of day length on growth and flowering, plants can be divic
into three groups (see Table 10.10).
10 • Plant morphology and physiology
Long-day plants
• Produce vegetative
growth when the day
length is short.
• Produce flowers when
the day length is long.
• Examples: radish,
beetroot, petunia
Short-day plants
• Produce vegetative
growth when the day
length is long.
• Produce flowers when
the day length is short.
• Examples: pigeon
pea, poinsettia,
chrysanthemum
Day-neutral plants
• Insensitive to day
length.
• Grow vegetatively to
maturity and produce
flowers all year round.
Examples: ochro,
cucumber, carrot, tomato
Table 10.10 Effects of day length on growth and flowering.
Figure 10.29 Poinsettias are shortday plants.
What are the differences between long-day and
short-day plants?
growth ►
development ►
In the Caribbean, artificial techniques are used to bring certain short-day plants,
such as poinsettias and chrysanthemums, into flower around Christmas time when
they are in demand. The plants are kept in the vegetative state by keeping them
in long days, and then induced to flower by exposing them to shorter day lengths.
10.6 Environmental factors and plant growth
and development
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 which occur
during the different stages of growth. Plant growth and development are affected
by environmental factors — these should be taken into consideration before crop
production is undertaken.
Understanding environmental factors, together with the experience of advisors,
can assist farmers in choosing crops which are suitable for their land. It is not
possible to change the climate, but understanding weather patterns and soil fertility
can result in better crops.
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
What happens to plants if they are grown in the
dark?
ITC151
What effect does the amount of rainfall have on
growth and development?
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, 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.
IA
1l
Sunlight
etiolation ►
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.
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).
167
411
11
Section B: Crop Production
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.
Soil fertility
Soil fertility is important so that plants can obtain the necessary nutrients for
growth. Soils with low fertility hamper growth and development, resulting in low
yields. Soil fertility can be managed in a number of ways (see Chapter 8).
Pests and diseases
Pests and diseases limit growth and development. Before planting, a farmer might
treat the soil with pesticides and fungicides and remove weeds. Once the crop is
planted, regular inspection is needed to detect the first signs of an infection or
infestation so that treatment can be applied.
• Monocots are flowering plants which bear seeds containing one cotyledon;
dicots are flowering plants with seeds containing two cotyledons.
• Monocots have fibrous roots, leaves with parallel veins and scattered vascular
bundles in the stem.
• Dicots have tap roots, leaves with a network of veins and stems with cylindrically
arranged vascular tissue.
• The seeds of flowering plants contain an embryo and a food store enclosed by
a seed coat.
• Roots may be tap, fibrous, aerial or adventitious with central vascular tissue
and a wide cortex.
• Stems may be herbaceous or woody.
• Leaves are flat, thin structures adapted for photosynthesis. They have an upper
and a lower epidermis with stomata for exchange of gases.
• The main leaf tissue is the mesophyll; this is made of cells containing chloroplasts,
which have chlorophyll.
• The vascular tissue in leaves is in the midrib and in the network of veins. It
consists of xylem and phloem.
• Plants reproduce sexually, through pollination, and asexually by natural and
artificial methods.
• Flowers consist of a flower stalk, receptacle, petals, sepals and the reproductive
structures.
• The male reproductive structures are the stamens, which have a filament
bearing anthers in which pollen grains (containing male gametes) are formed.
• The female reproductive structures are the carpels, which consist of a stigma, a
style and an ovary in which the ovules (containing female gametes) develop.
• Flowers may be self-pollinated or cross-pollinated by several pollinating agents.
• Insect-pollinated flowers are brightly coloured, scented, with sticky pollen and
nectaries to attract insects.
• Wind-pollinated flowers are small, with no nectar and produce masses of light
smooth pollen grains.
• Pollination and fertilisation are important to agriculture in the production of
fruits and seeds in crop plants.
• Fertilisation is usually necessary for fruit and seed formation.
• Asexual reproduction may use vegetative organs, such as suckers and rhizomes;
grafting and tissue culture are also used.
• Asexual reproduction produces genetically identical offspring without the
formation or fusion of gametes.
168
10 • Plant morphology and physiology
•
•
•
•
•
•
•
•
•
•
Answers to !Ns
Artificial methods of vegetative propagation result in identical plants that can
be produced quickly in large numbers and are 'true to type'.
Seed germination requires water, a suitable temperature and oxygen.
Seed germination in dicots may be epigeal, when the cotyledons come above
the ground, or hypogeal when the cotyledons remain below the ground.
Seedlings are raised in containers such as seedboxes, Speedling trays or plastic
bottles.
Seeds need to be sown in a potting soil mixture (which provides nutrients),
kept moist and at a suitable temperature. Seeds sown in containers are usually
kept in a nursery.
A seedbed needs preparation so that it is free from weeds and pests, will drain
easily, is fertilised and the soil should have a fine tilth.
Seeds may be sown by scattering, placing in drills, or mixing with sand or water.
If seedlings grow too closely they need to be thinned out to give them space.
Before transplanting to field plots, seedlings need to be hardened to get them
used to full sunlight.
Plants respond to environmental factors such as light (phototropism) and
daylength (photoperiodism).
1 -101
One from corn, rice, sugar cane, bamboo for monocot or another correct
example; and one from cabbage, cotton , citrus for dicot or another
correct example.
11112
Monocot flowers have parts in 3s, often petals and sepals are small
and inconspicuous. Dicot flowers have parts in 4s and 5s, with brightly
coloured, large petals.
IT03 Tap, fibrous, adventitious and aerial.
ITN The xylem and the phloem are transporting tissues: xylem transports
water and mineral ions, and the phloem transports food substances in
solution.
ITQ5 The pericycle is a single layer of cells inside the endodermis. It produces
lateral roots and cambium tissue.
MN The epidermis has stomata; the cortex is narrower; there is no
endodermis; the vascular tissue is in strands or bundles and not in the
centre; there is a central area of pith.
MR Herbaceous stems are soft and often green, whereas woody stems are
hard and covered with a layer of bark.
ITQ8
Monocot leaves are long and thin with parallel veins and often with no
definite midrib; dicot leaves are broader with a network of veins and have
a definite midrib.
ITQ9 Protects internal tissues; slows down the evaporation of water; stomata
allow gas exchange.
11- 010 The seed coat, the micropyle and the scar (hilum).
11:111 Food is stored in the endosperm of a maize seed and in the swollen
cotyledons of a bean seed.
111112 The stamens consist of a filament which bears anthers in which the pollen
grains are formed.
ITC113 The function of the style is to connect the stigma to the ovary.
11:114 Pollination is the transfer of pollen from the anthers to the stigma.
111115 Three from: wind, water, insects, birds, humans.
1 -1016 It is light and smooth so that it is easily carried in the wind.
169
Section B: Crop Production
11017 One male gamete fuses with the egg cell to form a zygote; the other male
gamete fuses with nuclei in the ovule to form the food store.
11018 Any five from: bulb, corm, runner, rhizome, tuber, sucker, stolon.
11019 The propagation of plants by vegetative parts, not involving the
production (or fusion) of gametes.
11020 Sugar cane, cassava and sweet potato.
ITQ21
Tongue layering involves pegging down a stem to the ground where
it will form roots; air layering involves making a cut, applying rooting
hormone and keeping the region moist until roots form.
11022 The stock is the rooted stem; the scion is the piece of stem to be grafted
on to the stock.
11023 Mango, avocado and sapodilla.
11024 Genetically identical plants; large numbers produced in a short time; can
be disease-resistant; produce dwarf trees; quality can be assured; can
propagate plants that do not produce viable seeds.
11025 When 100 seeds are planted, it is the number that germinate successfully.
6
ITQ26 Should be kept in sealed airtight containers and cool conditions.
I
ITQ27 Air (oxygen), suitable temperature and moisture.
1
11028 Because their seed coats are very thick and scarifying them allows water
in more quickly.
11029 In epigeal germination, the hypocotyl elongates and brings the cotyledons
above the soil. In hypogeal germination, the epicotyl elongates bringing
the plumule above the soil but the cotyledons remain below the ground.
11030 Radicle emerges and grows down into the soil; the plumule covered by
the coleoptile emerges above the ground. The cotyledon remains below
the ground and absorbs food from the endosperm.
11031
Any three from: seedboxes, Speedling trays, tin cans, plastic bags, plastic
cups and plastic bottles.
11032 One seed planted in each compartment; no need for thinning out; easy
and light to handle; easy for transplanting; can be used again.
11033 It is close to the field plot so that seedlings do not have to be transported.
It saves the fa rmer time and labour.
11034 3 m long by 1 m wide; cambered for drainage; manured and fertilised;
fine tilth.
11035 Scattered or broadcast; in seed drills; mixed with water; mixed with sand.
11036 Mixed with water in a watering can and sprayed on to the soil.
11037 It should be transparent to allow the light in for photosynthesis of the
seedlings.
11038 Any two from: reduce competition for light; reduce competition for
water; reduce competition for nutrients; provide more space for growth.
11039 To get them used to full sunlight.
11040 Early in the morning, late in the evening or when the weather is cloudy
to reduce the effect of hot temperatures and avoid wilting.
11041 carbon dioxide + water -. sugar + oxygen
In the presence of sunlight and chlorophyll.
11042 Light is needed for photosynthesis and the higher the light intensity the
greater the rate of photosynthesis.
11043 carbohydrate + oxygen -, carbon dioxide + water + energy
11044 For the formation of new cells, for the maintenance of the protoplasm,,
and for the transport of materials around the plant.
170
10 • Plant morphology and physiology
11045 Plant cells lose their turgor and the plants wilt.
11046 Because the movement of substances against the concentration gradient
requires energy from respiration.
11047 Some are absorbed by diffusion if there is a higher concentration in the
soil solution than in the plant. If the concentration is greater in the plant
than in the soil solution, ions are taken up by active transport.
11048 The xylem is specialised for the transport of water and mineral ions; the
phloem is specialised for the transport of soluble food substances.
11049 Long-day plants grow vegetatively when the day length is short and
produce flowers when the day length is long. Short-day plants grow
vegetatively when the day length is long and produce flowers when the
day length is short.
11050 They grow long and thin, lack chlorophyll and have unexpanded leaves.
They die eventually.
11051 Too much rainfall slows down plant growth; too little rainfall causes
wilting and eventually death.
Examination-style
questions
Multiple Choice Questions
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 3s.
2. Which of the following plants is a dicot?
A corn
B bamboo
C sugarcane
D cabbage
3. Which type of root system does a mango plant have?
A tap
B fibrous
C adventitious
D aerial
4. Monocot leaves 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. A stolon is:
A an underground shoot growing from the base of the plant
B a swollen underground stem
C a slender creeping stem
D a thick underground stem
7. Which of these plants has hypogeal germination?
A kidney bean
B tomato
C cabbage
D pigeon pea
171
Section B: Crop Production
8. 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
9. (a) (i) Explain the meaning of 'pollination'.
(ii) List the agents of pollination.
Describe the major features of insect-pollinated flowers.
Clearly distinguish between: (i) self pollination, and
(ii) cross pollination.
(d) State the importance of pollination in agriculture.
10. (a) (i) Explain the meaning of 'asexual reproduction'.
(ii) List, with specific examples, the TWO main methods of asexual
reproduction.
(b) Complete the table below:
(b)
(c)
Vegetative organs
Two examples
suckers
bulbils
corms
rhizomes
(c) Naming appropriate examples, differentiate between:
(i) stem tuber, and
(ii) root tuber.
11. (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 the budding tape?
12. (a)
(i) Explain the meaning of 'grafting', naming TWO examples of
grafted plants.
(ii) List TWO techniques of grafting which are commonly used.
(b) Describe the techniques of grafting a mango plant, using the
following headings:
(i) Materials required.
(ii) Procedure (step by step).
(c) (i) Naming appropriate examples, explain the meaning of 'tissue
culture'.
(ii) Briefly state some advantages of tissue culture.
13. (a) What is the meaning of 'germination'?
(b) Using appropriate examples, explain the difference between:
(i) epigeal germination, and
hypogeal germination.
(c) Using diagrams, describe fully the stages of germination in the kidney
bean.
14. (a) Name FOUR different types of containers used for seedling
production.
(b) What are some desirable features of a potting soil mixture?
(c) List FOUR major advantages of using containers for seedling
production.
1
•
172
10 • Plant morphology and physiology
15. (a) What are the desirable features of a seedbed for raising tomato
seedlings?
(b) Outline, step by step, the procedure for preparing a seedbed.
(c) State the main advantages of a seedbed for the farmer.
16. (a) Explain the meaning of the following as they relate to seedlings:
(i) hardening
(ii) transplanting.
(b) At what time of day, or under what weather conditions, should
seedlings be transplanted?
(c) Outline the procedure for transplanting tomato seedlings from a
Speedling tray to a field plot.
17. (a) State the meaning of: (i) photosynthesis, and
(ii) respiration.
(b) Explain this statement: 'respiration is the opposite of photosynthesis'.
(c) State the importance of photosynthesis and respiration to plant
growth.
18. (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.
19. (a) Draw and label fully a cross-section through a young stem.
(b) List the main functions of stems.
(c) Explain the process of translocation in stems.
173
1
- 1 "1
'
1 1 [1 1
I,
g enetics,
°°°°°° breedi n g and
I
h4
i c h ri ol o p
hi ff
'
By the end of
this chapter
you should be
able to:
3
3
3
3
3
3
3
3
3
Concept map)
describe cell division (mitosis and meiosis)
understand genes and chromosomes and how inheritance occurs
describe how variation contributes to plant breeding
understand the terms homozygous and heterozygous, dominance and
recessiveness
describe monohybrid inheritance and predict the outcome of
monohybrid crosses
understand the importance of selection in the development of different
varieties of crop plants
state the value of breeding for increased yields and resistant varieties
explain the significance of biotechnology
evaluate the benefits and concerns of introducing genetically
engineered crops.
Plant genetics, breeding and biotechnology
--1 Monohybrid crosses
nucleus
L
Biotechnology
Breeding
Principles of genetic
inheritance
chromosomes
genotype and phenotype
genes
Cell division
mitosis
Hybridisation
meiosis
Selection
variation
increased yields
resistant varieties
174
significance in crop
i mprovement
benefits and
concerns
11 Plant genetics, breeding and biotechnology
11.1 The principles of genetic inheritance
Write a definition of selective breeding.
rr
How do plant cells differ from animal cells?
selective breeding ►
Explain what an organelle is and name TWO
organelles in the cytoplasm of plant cells.
unicellular, multicellular ►
• •
cell wall
---nucleus
E\
cytoplasm
•
•^
-.-
-vacuole
cell membrane
•
chloroplasts
•
•
•
•
Figure 11.1 A
typical plant cell.
cell membrane ►
cytoplasm, organelles ►
mitochondria ►
ribosomes ►
chromosomes, nucleus ►
genetic code ►
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, confer resistance to disease and increase
the nutritional content of the crop.
The basic structure of all organisms is the cell. Some organisms, such as bacteria,
are unicellular and consist of only one cell. Most organisms are multicellular and
consist of large numbers of different cells organised into tissues and organs.
Cells
All cells have the following features:
• a cell membrane surrounding the living material of the cell
• the cytoplasm: the living material of the cell
• a nucleus containing chromosomes.
Plant cells (see Table 11.1) 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
Cytoplasm
Nucleus
DNA ►
cell wall ►
Cell wall
vacuole ►
Vacuole
Chloroplasts
chloroplasts ►
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).
otosynthesis takes place and food is
Organelles in which
leaves and green stems.
manufactured. Fou
Table 11.1 The functions of plant cell structures.
Cell division
cell division ►
nuclear division ►
mitosis ►
meiosis ►
New cells are formed by cell division, during which 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 are divided
into two equal sets so that the nucleus in each new cell has exactly the same
number of chromosomes as the parent cell; this type of division occurs when
new cells are produced throughout the life of a living organism
• meiosis: this involves the formation of gametes (sex cells) in the reproductive
organs; the nucleus of each gamete has half the number of chromosomes as
the parent cell; when fertilisation occurs the zygote has the correct number of
chromosomes restored.
175
Section B: Crop Production
Mitosis
deoxyribonucleic acid ►
genes ►
centromere
(holds two chromatids
together)
chromosome
gene
(segment of DNA that
codes for a trait)
chromatids
(identical copies)
When a cell is not dividing, it is impossible to see the detailed structure of the
nucleus. The chromosomes are present as very long strands of deoxy ribonucleic
acid (DNA). Just before the cell divides, these long strands get sho rt er and fatter:
they form structures (chromosomes) which can be seen when cells are viewed
using a light microscope. Each chromosome consists of a pair of identical chromatids
joined by a centromere. The genes are located on the chromatids. A gene is a
hereditary unit consisting of a sequence of DNA that occupies a specific location on
a chromosome and determines a pa rt icular characte ri stic in an organism.
During mitosis, the following stages occur:
• the chromosomes become visible
• the nuclear membrane disappears
• the chromosomes line up across the middle of the cell (the equator)
• the chromatids of each chromosome separate and move to opposite ends of
the cell
• the chromatids become the new chromosomes of the daughter cells
• a nuclear membrane forms around each set of chromosomes
• the cytoplasm of the cell divides and a new cell wall forms between the two
daughter cells (these are the new cells resulting from mitosis).
The daughter cells each receive a complete set of chromosomes identical to those
of the parent cell. The daughter cells are genetically identical to the parent cell as
chromosome. they have exact copies of the genes carrying the same information. There is no
va ri ation. This type of division occurs in asexual reproduction in bacteria and in
other unicellular organisms, such as Amoeba.
Figure 11.2 The structure of a
Parent cell
nucleus
two pairs of similar (homologous)
chromosomes (total 4)
cytoplasm
centromere at centre
of chromosome
chromosomes arrange themselves
singly across centre of the cell
T '
1
List the stages of mitosis.
r r
^,
A f itwo
(
centromeres divide and
chromosomes separate into
two daughter cells
body
v
v
v
==
---------- --------------
NNNN
each chromosome makes
an exact copy of itself
(replication)
two daughter cells formed,
each with the same
4 chromosomes of the parent cell
cells
Why are the daughter cells identical to the parent
Figure 11.3 The stages of mitosis.
cell?
h•Diploid and haploid
II (I
In each normal body cell of an organism, there is a fixed number of pairs of identical
diploid ► chromosomes. This is known as the diploid number of chromosomes. For humans,
the diploid number is 46, consisting of 23 pairs. In peas, the diploid number is 14.
The genes on each member of a pair code for the same characte ri stics.
Explain why the body cells of an organism are
diploid.
176
1
11 • Plant genetics, breeding and biotechnology
haploid ►
How does meiosis differ from mitosis?
When mitosis takes place, separation of the chromatids ensures that the daughter
cells have the same diploid number of chromosomes and therefore the same genes
as the parent cell.
When gamete formation occurs in meiosis, the way in which the chromosomes
divide ensures that each gamete has one of each pair of chromosomes. For example,
human gametes will have 23 chromosomes and pea gametes will have 7. This is
known as the haploid number. When fertilisation occurs, the diploid number of
chromosomes is restored, each gamete contributing one of each pair to the zygote.
One of each pair of chromosomes comes from the male parent and the other from
the female parent.
Meiosis
1
Where does meiosis occur in plants?
Meiosis is sometimes referred to as a 'reduction division' as it reduces the number
of chromosomes in the daughter cells. One major difference between mitosis and
meiosis is that meiosis involves two divisions of the nucleus. The first division
separates the pairs of chromosomes; the second division separates the chromatids.
Stages
Parent cell
nucleus
two pairs of similar (homologous)
chromosomes (total 4)
cytoplasm
centromere
each chromosome makes
an exact copy of itself
(replication)
chromosomes arrange themselves
in pairs across centre of cell
centromeres do not divide double chromosomes go into
daughter cells
further cell division occurs centromeres divide so
chromosomes separate into
four daughter cells, each with
two chromosomes
Four daughter cells formed,
each with half the original
number of chromosomes
Four gametes
During meiosis the following stages occur:
• the chromosomes become visible
as pairs of chromatids joined by a
centromere
• chromosomes pair up (form
homologous pairs)
• the nuclear membrane disappears
• the homologous pairs of chromosomes
line up on the equator of the cell
• the pairs separate, each moving to
opposite ends of the cell
• a new nuclear membrane forms around
each set of chromosomes
• the cytoplasm divides
• the nuclear membrane of each
daughter cell disappears
• the chromosomes line up on the
equator of each daughter cell
• the chromatids of each chromosome
separate and move to opposite ends of
the cell
• the chromatids become the new
chromosomes of the daughter cells
• a new nuclear membrane is formed
around each set of chromosomes and
the cytoplasm divides.
Figure 11.4 Stages in meiosis.
a
b
(
—a—a—) I pair of homologous
chromosomes
j
A
B
Figure 11.5 Each chromosome of a
pair carries one allele for a particular
characteristic: a and A are alleles, so
are b and B.
alleles ►
As a result of meiosis, four daughter cells are formed.
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
177
Section B: Crop Production
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
Define (a) a gene, and (b) an allele.
characteristic. These alleles may both be the same or they may be different.
crossing-over ► During the first division of meiosis, crossing-over may occur in which the
chromatids of the homologous chromosomes intertwine and portions of these
chromatids may be exchanged. This means that alleles on one chromosome of
S
a pair may be exchanged for the alleles on the other chromosome. When the
Why does crossing-over result in variation?
I 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
variation ► 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.
1
11.2 Plant breeding
How characteristics are inherited
dominant ►
recessive ►
genotype ►
phenotype ►
homozygous ►
heterozygous ►
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 their tongue may have inherited one
allele for tongue rolling from their mother and another from their father. But if the
two alleles were different, that is one for tongue rolling and one for non-rolling,
the person would still be able to roll their 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 their tongue.
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 their tongue
could have the following combinations of alleles: RR or Rr. A person unable to
roll their tongue could only have the combination rr.
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.
As we have seen, tongue rolling is a phenotype and there are two genotypes
for this: RR and Rr. In RR both alleles are the same and the person is said to be
homozygous for the characteristic. The other genotype ( Rr) has two different alleles
and the person is said to be heterozygous. A non-roller can only be homozygous
(rr) with both recessive alleles.
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 he 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
178
r
Rr
Rr
r
Rr
Rr
11 •
Plant genetics, breeding and biotechnology
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.
Distinguish between (a) genotype and phenotype,
(b ) dominant and recessive, and (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,
so the table shows what the genotypes of the offspring are likely to 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 tkEite will be a non-roller. So the
ratio of phenotypes is 3:1.
Inheritance in plants
Characteristics in plants are inherited in exactly the same way as shown above 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 below.
Back cross on TT plants
Gametes
t
t
T
Tt
Tt
T
Tt
Tt
All the plants will be tall
Gametes
T
T
t
Tt
Tt
t
Tt
Tt
If the offspring of this cross are interbred, there will be mixture of tall and dwarf
plants produced as shown below.
Back cross on Tt plants
Gametes
t
t
T
Tt
Tt
t
tt
tt
Half the plants will be
tall and half dwarf
Figure 11.6 A back cross or test cross.
test cross, back cross ►
Explain how a back cross or test cross works.
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.
It is not possible to determine the genotype of the tall plants by looking at them. If
a plant breeder wanted a pure-breeding variety of pea plants, it would be necessary
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. This type of cross
is illustrated in Figure 11.6.
Take a look at Figure 11.6. If the plant breeder finds that some dwarf plants grow
from seeds resulting from the back cross, then the parents were heterozygous. But
if all the seeds produce tall plants, then the parents were homozygous.
Monohybrid inheritance
The cross shown in Figure 11.6 involves a single pair of alleles which code for a pair
monohybrid inheritance ► 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:
if you arrange people in your class in a line from shortest to tallest there might be
179
Section B: Crop Production
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.
Farmers have traditionally saved seed from the best of their crop to sow the next
year and in this way, over a long period, crops have been improved. A good
example of this type of artificial selection is shown by different members of the
cabbage family, the Brassicas (see Table 11.2). A wide range of vegetables have
been selectively bred over many years.
Vegetable
Special characteristics
Broccoli
Brussels sprouts
Cauliflower
Thick stem and green flower head.
Cabbage
Kale
Kohlrabi
Many small lateral buds.
Large white flower head.
Large terminal bud.
Many large leaves.
Thick edible stem.
Table 11.2 Brassica vegetables and their special characteristics which have been
selectively bred.
caooage
broccoli
cauli
Figure 11.7 Some vegetables of the cabbage family.
The staple diets of most countries involve members of the Graminae, or grass
family. This family includes rice, maize, wheat, oats, barley, rye and millet. These
180
11 Plant genetics, breeding and biotechnology
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 it is hoped will be combined in
the offspring. For example, if a variety of wheat with short stems is crossed with a
variety 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 of enormous importance in feeding the increasing world population. There is
now much interest in developing disease-resistance and drought tolerance in crop
What is a hybrid?
I
plants.
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
Why is it important to keep examples of older
a change in climate, some of our present varieties might not thrive and it would be
varieties of crop plants?
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
seed banks ► varieties. Seeds are kept in seed banks, where conditions are controlled to maintain
their viability. Collections of plants in botanical gardens and the preservation of old
varieties of fruit trees in nurseries add to the reserves of genes which could be used
germplasm ► 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.
Practical activities:
1. Grow different varieties of a crop, such as tomatoes. Observe the stages of growth
and the different characteristics of the varieties. Make notes about each variety.
2. Visit botanical gardens, parks and protected areas. Make notes about the different
varieties of plants present.
11.3 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 and we also use fungi to make cheese and bacteria to make
yoghurt.
Using bacteria to make disease-resistant plants
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
genetic engineering ► 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 ►
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 which contain the new DNA. These cells are then used to produce
tiny plants which can be transplanted and which will grow into mature, disease-
181
Section B: Crop Production
genetic modification ( GM) ►
1. Gene coding for disease resistance is isolated
sticky ends on gene
2. Plasmid is removed from the bacterium
bacterium
Pcircu1ar bit of DNA
called a plasmid
3. The gene is introduced into the plasmid
gene coding for disease resistance
4. The plasmid is put back into the bacterium
bacterium
5. The plant is infected with the bacterium; in this way
the gene for disease resistance enters the plant
Figure 11.8 Introducing a diseaseresistance gene into a crop plant.
Give THREE examples of micro-organisms that
have been used to make food for humans,
What is genetic engineering?
1
11
Give THREE examples of genetically modified
crops.
Practical activity:
Use the internet to build up a list
of genetically engineered crops.
182
resistant plants. The tiny plants will all be genetically identical and they will all
have the gene for disease-resistance.
There are techniques other than using bacteria that can be used to insert new
genetic material into plants.
There are also other examples of genetic modification (GM) which are used to
improve crops:
• Herbicide-resistance can be bred into crop plants: the crop is then sprayed with
herbicide to get rid of the weeds and only the weeds will be destroyed, not the
crop (this has been done with soya).
• Resistance to insect pests: a gene is introduced into the crop plant which
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: a gene has been introduced into rice plants which shows
increased resistance to the rice stripe virus.
• Improved flavour and keeping qualities: genetic modification to tomatoes
prevents the softening of tomatoes as they ripen without altering the flavour
and colour.
Controversy about GM
Research into GM crops continues and the possibilities are huge, with apparent
benefits to growers and for food production. However, not everyone believes that
genetic modification is a good thing.
Some of the objections are:
• it is a new technology and long-term effects are not known
• the effects of eating GM products on human health cause particular concern
• the modified genes from one species might get into other species
• GM technology is an expensive process; often the technology has been
developed by a big corporation who charges much 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 have a choice as to whether or not
they buy it.
Other uses of GM technology
Genetic engineering is used in medicine to produce human hormones, such a:
insulin and growth hormone. It is also used to produce the enzyme (rennin) use
in cheese making. Traditionally, this enzyme was extracted from the stomachs a
young calves, kids or lambs, but now it can be produced from genetically modified
yeasts.
• Selective breeding involves selecting the crop plants and stock animals with th
most favourable characteristics and using these to breed.
• The basic structure of a plant cell consists of a nucleus, surrounded by cytoplast
and enclosed by a cell membrane. The cell contents are surrounded by a ce
wall.
• Plant cells differ from animal cells in that they contain chloroplasts and
vacuole containing cell sap.
• The nucleus contains the chromosomes, which carry genetic information in 11
form of the genetic code made up of DNA.
11 • Plant genetics, breeding and biotechnology
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Answers to ITQs
New cells are formed by cell division where the nucleus divides followed by
division of the cytoplasm. There are two types of nuclear division: mitosis and
meiosis.
Mitosis is the type of nuclear division associated with the production of
new cells and growth. It involves one division of the nucleus to separate the
chromosomes. The two daughter cells produced are genetically identical to the
parent cell.
Meiosis is the type of nuclear division associated with the production of gametes.
The number of chromosomes in the cells is halved. It involves two divisions of
the nucleus: one to separate the pairs of chromosomes and one to separate the
chromatids.
Meiosis results in the formation of four daughter cells, each with half the
number of chromosomes of the parent cell.
Meiosis produces variation, but there is no variation as a result of mitosis.
Variation results from the exchange of portions of homologous chromosomes
during the first stage of meiosis.
The body cells of organisms have the diploid number of chromosomes, but the
gametes have half that number, the haploid number. When fertilisation occurs
the diploid number is restored.
A gene is a section of a DNA molecule that codes for a particular characteristic.
Genes have different forms and these are known as alleles.
The genes are arranged linearly along the chromosomes and always occupy the
same position on a specific chromosome. Each chromosome of a pair carries
one allele for a particular characteristic.
Some alleles may be dominant and their effects show up even if only one is
present in an individual; others are recessive and do not show up if there is a
dominant allele present.
If both alleles for a characteristic are the same, the individual is said to be
homozygous for that characteristic, but if they are different then the individual
is said to be heterozygous.
The combination of alleles is the genotype; the appearance of the characteristic
is the phenotype.
Monohybrid inheritance involves the inheritance of a single pair of alleles
coding for a pair of contrasting characteristics.
A hybrid is formed when two different varieties are crossed.
Crop plants may be selectively bred to increase yields and to develop diseaseresistance and drought tolerance.
It is important to conserve seeds so that there is a reserve of genetic material
from which to breed new varieties for changing circumstances.
Biotechnology uses plant and animal cells and micro-organisms to make useful
products for humans.
Genetic engineering is the alteration of the genes of an organism and involves
the introduction of a gene from another living organism.
Bacteria are used to insert pieces of DNA for particular characteristics into host
cells.
Genes that confer disease-resistance, resistance to insect pests, protection
against viruses and improved flavour have all been introduced into crop plants.
Many people have doubts about the safety of genetically modified crops.
ITCH
Selective breeding is choosing those crop plants or stock animals with the
most favourable characteristics and using them to breed new crops and
animals.
ITC12
Plant cells differ from animal cells because they have a cell wall,
chloroplasts and a large vacuole filled with cell sap.
183
t
^^
Section B: Crop Production
1103
Organelles are small structures in the cytoplasm of cells in which
metabolic activities take place: mitochondria for respiration, ribosomes for
protein synthesis, chloroplasts for photosynthesis.
1104 Chromosomes become visible; nuclear membrane disappears;
chromosomes line up along the equator; chromatids separate and go to
opposite ends of the cell; chromatids become new chromosomes; nuclear
membrane reforms; cytoplasm of cell divides; new cell wall forms.
IT05 Because the chromosomes are shared equally between the cells and they
are exact copies of the parent chromosomes.
IT06 The body cells have one of each chromosome from the mother and one
from the father.
1107 Meiosis involves two divisions of the nucleus; one to separate the pairs of
chromosomes and one to separate the chromatids. There is the possibility
of variation.
F
t
1108
In the anthers during the formation of pollen grains; and in the ovary
during the formation of the female cells.
1109
A gene is a section of a DNA molecule that codes for a particular
characteristic. An allele is an alternative form of a gene.
Crossing-over involves the exchange of portions of chromatids which
may carry different alleles. This leads to different combinations of alleles
11010 when separation of the chromatids occurs.
1
1
t
t
1TQ11
11012
Genotype is the different combination of alleles; phenotype is the
appearance of the characteristic. Dominant means that the characteristic
determined by an allele is the stronger and will appear in the phenotype
if it is present; recessive means that the characteristic does not show in
the phenotype unless the dominant allele is missing. Homozygous mean
that both alleles for a characteristic are the same; heterozygous means
that the alleles are different.
A back cross involves carrying out a cross with an organism whose
genotype is known, usually the homozygous recessive. If you know the
genotype of one parent then it is possible to work out the unknown
genotype. You will always get some homozygous recessive offspring if the
unknown is heterozygous.
11013 A hybrid is the result of crossing two different varieties.
11014 It is important to keep seeds of older varieties so that there is a reserve of
genetic material from which to develop new varieties.
11015 Yeast used in brewing, fungi used in cheese-making and bacteria for
making yoghu rt .
11016 Genetic engineering is the introduction of genes from one organism into
another organism.
11017 Herbicide-resistant soya; improved flavour in tomatoes; virus-resistant
rice.
184
11 Plant genetics, breeding and biotechnology
Examination-style
questions
Multiple Choice Questions
1. All living cells have:
A cell walls
B chloroplasts
C large vacuoles
D cytoplasm
2. Which of the following statements about mitosis is true?
A Homologous chromosomes pair up.
B Daughter cells are identical to the parent cell.
C Four daughter cells are formed.
D Two divisions of the chromosomes take place.
3. 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
4. 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
5. 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 he could find out if these seeds
were 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 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.
185
V
^^^IIIII III IIIt111t1U
mmmn.n..............
1111
Cro
By the end of
this chapter
you should be
able to:
3
,/
/
/
3
3
3
3
3
3
3
hosbaodr
P
describe cropping systems
describe cultural practices associated with crop production
evaluate the benefits of different cultural practices
understand the nature of weeds and their effect on crops
describe different ways in which weeds can be controlled
name different pests and discuss the damage they cause to crops
describe how major crop diseases are transmitted
identify appropriate methods of managing pests and diseases in crops
discuss the use of chemicals in the environment
grow a selection of crops
state why plant quarantine is necessa ry .
Concept map
Cropping
systems
Crop husband ry
Weeds
Crop
Pest and
diseases
disease
management
Cultivation of
vegetable crops
ngi
acteri;
Types
ixed cropping
tercropping
op rotation
lased cropping
rip/contour croppi
ixed farming
ever cropping
Crop production
activities
ruses
Effect on
crops
Cost analysis
Integrated Pest
Weed
control
Management (IPM)
varieties
Cultural
practices
moulding
mulching
staking
pruning
Pests
Damage caused
by biting and
chewing pests
Damage caused
by piercing and
sucking pests
186
Chemicals in the
environment
Pollution:
atmosphere
groundwater
eutrophication
Importance of
plant quarantine
2 Crop husbandry
12.1 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.
Sometimes a combination of cropping systems may be used, depending on the
nature of 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 ► Monoculture is the continuous cultivation
1
List FOUR major cropping systems practised
locally or regionally.
moo
State ONE advantage and ONE disadvantage of
monoculture.
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 a build-up and rapid
spread of pests and diseases which attack
the crop, e.g. froghopper infestations and
smut disease in sugar cane.
Monoculture is a risky business for the
farmer because he has invested a lot of
effort into growing only one crop. Failure
of the crop can result in severe economic Figure 12.1 Monoculture — here
loss. However, some farmers have become sugar cane is being grown to the
exclusion of other crops.
specialised in the cultivation of a specific
crop, such as rice, pineapple or pawpaw.
The farmer needs to invest in the machinery required for the cultivation, harvesting
and preparation for market of the chosen crop. For example, monoculture of sugar
cane demands investment in a sugar cane combine harvester.
Multiple cropping
multiple cropping ►
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
peasant farmers. This type of cropping system provides income on a regular and
continuous basis for the farmer.
The crops are chosen carefully so that:
• some crops have a shorter growing period and others a longer growing period
• crops grow to different heights
• some are deep-rooted and others shallower-rooted
• the water and nutrient requirements of the crops are not the same.
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
187
Section B: Crop Production
• control of soil erosion as different crops provide different forms of vegetative
cover to 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 soyabean and pigeon pea, root crops
and cereals.
Figure 12.2 Multiple or mixed
cropping.
Intercropping
intercropping ►
IK
Explain the difference between multiple cropping
and intercropping.
Intercropping is the cultivation of a short-term crop, such as lettuce, between the
plants of a medium-term crop, such as sweet pepper. It enables the farmer to earn
some quick income from the sale of the lettuce crop while the main crop of sweet
peppers develops. It requires careful selection in terms of compatibility so that one
crop is not smothered by the rapid growth of the other.
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 ► Crop rotation is the cultivation of selected
crops 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 deeprooted and shallow-rooted crops enables
soil nutrients to be used from different
levels in the soil. The other benefit is that
the build-up of pests and diseases in the
soil is prevented (pests and diseases are
usually specific to one type of crop).
*
Area I
Area 2
Area 3
Leaves
Fruits
Roots
Legumes
Leaves
Fruits
Roots
Legumes
Leaves
Fruits
Fruits
Roots
*^
Legumes i
Leaves
Year
t
Area 4
Legumes
Year
2
Roots
Year
3
00
Year
4
Figure 12.3 An example of a four-
Phased cropping
phased cropping ►
r
State TWO advantages of phased cropping.
year crop rotation.
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 receive a steady income over time. This type of cropping
prevents an oversupply, or glut, of a commodity which would have the effect of
lowering the price on the market.
Strip cropping and contour cropping
strip cropping ►
contour cropping ►
188
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.
12 •
Crop husbandry
maize (crop)
grass
cabbage (crop)
grass
pigeon peas (crop)
••■
Explain what is meant by contour cropping and
give ONE reason why it is practised on sloping
land.
Figure 12.4 Strip cropping.
Mixed farming
mixed farms ►
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 35) are mixed farms.
Cover cropping
cover cropping ►
1106
Explain why cover cropping is referred to as
green manure.
Practical activity:
Plan a one-year crop rotation
programme using leaf crops,
legumes, root crops and a fruit or
vegetable, such as tomato.
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
ploughed into the soil before the land is re-planted. The cover crop, often referred
to as 'green manure', provides a cover of vegetation for the soil and adds organic
matter when 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, particularly between rows of fruit trees in an orchard.
12.2 Cultural practices associated with crop
production
Many activities (see Table 12.1) 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 Chapter 8.
Cultural
practice
Moulding
Procedure
Benefits
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.
• 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 used
• improves soil fertility
• controls weed growth
189
Section B: Crop Production
Cultural
practice
Staking
Pruning
Give FOUR reasons for staking plants.
What are the benefits of mulching?
Procedure
Benefits
A stake is placed beside a
plant; normally round wooden
stakes, 2 m long, 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 8 and
then wound twice around the
stake before tying securely;
tying is done at 20 cm
intervals along the stem.
Dry, diseased or excessive
twigs, leaves and branches of
a plant are removed using a
sharp knife, a pair of secateurs
or a small pruning saw.
• supports plants with weak stems,
e.g. tomato
• 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
a.,.
1`
Practical activities:
1. Produce a fruit, leaf, flower and
Irrigating
Applying water to the soil for
the benefit of crop plants; can
be carried out in a variety of
ways.
Fertilising
The application of fertilisers to
crop plants; details of fertilisers
are given in Chapter 8.
root vegetable crop. During the
sowing, cultivation and growth
of the crop, use appropriate
,
cultural practices from
Table 12.1.
2. Develop your own notes and
drawings about the production
of vegetable crops.
• improves the shape of the plant
• encourages growth and
development of fewer, but larger
fruits
• enables air to circulate more
freely in the crop so discouraging
fungal diseases
• prevents spread of diseases to
other plants
• enables good growth and
development
• prevents crop loss through
wilting and death
• helps to regulate supply of soil
water for crops
• promotes growth, development
and production in the crop
• produces healthy plants
• improves and maintains soil
fertility
Table 12.1 Cultural practices involved in crop production.
12.3 The effects of weeds on crops
weed ► A weed is any plant that is growing in the wrong place — or where it is not wanted.
This definition 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 are in competition 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 (e.g. redhead) are poisonous to livestock, especially cattle and
horses which may stray on to the fields.
Why are weeds so successful?
Weeds are successful in competing with crop plants because:
• 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 which will be smaller but still produce seeds
• they produce large numbers of seeds under favourable conditions
190
12 Crop husbandry
• they can often reproduce vegetatively as well as 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 weeds, 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 faster than the crop and smother the crop
seedlings.
Most of the major weed species belong to just a few plant families: the grasses
( Gramineae), the sedges (Cyperaceae) and the composites, such as railway daisy
and red thistle (Compositae). In the Caribbean, annual and perennial grasses,
vines and woody plants can be problem weeds.
Figure 12.5 Nutgrass is a common
weed.
What is a weed?
Apart from producing many seeds, how else can
weeds reproduce?
Practical activities:
1. Collect and identify common
weeds.
2. Conduct a weed control trial.
Grow two identical crops under
identical conditions but allow
one crop to become infested
with weeds. Do the weeds
affect the yield?
Possible benefits of weeds
In general, weeds are harmful, but their rapid germination and growth on bare
soil provides a cover of vegetation which can help to prevent soil erosion due to
heavy rainfall.
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 other insects which prey on some crop pests.
12.4 Methods of weed control
It is important to control weeds within a crop to ensure a good yield and good
quality of produce.
Methods of weed control include:
• cultural control — adequate preparation of the land and cultural practices such
as hand weeding and hoeing
• chemical control — the use of weedkillers (herbicides)
• biological control — using other organisms to control weed growth
• integrated control — combining two or more methods which 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 from an authorised supplier will ensure that weeds
are not 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 in weed control. Some weeds are associated with certain
crops and planting different crops in rotation can control a particular weed.
For example, a parasitic weed called Striga affects maize, sorghum and cowpea;
this can be controlled by planting a different crop 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
191
pl .
Section B: Crop Production
• control of soil erosion as different crops provide different forms of vegetative
cover to 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 soyabean and pigeon pea, root crops
and cereals.
Figure 12.2 Multiple or mixed
cropping.
intercropping ►
rK
Explain the difference between multiple cropping
and intercropping.
Intercropping
Intercropping is the cultivation of a short-term crop, such as lettuce, between the
plants of a medium-term crop, such as sweet pepper. It enables the farmer to earn
some quick income from the sale of the lettuce crop while the main crop of sweet
peppers develops. It requires careful selection in te rms of compatibility so that one
crop is not smothered by the rapid growth of the other.
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 ► Crop rotation is the cultivation of selected
crops 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 deeprooted and shallow-rooted crops enables
soil nutrients to be used from different
levels in the soil. The other benefit is that
the build-up of pests and diseases in the
soil is prevented (pests and diseases are
usually specific to one type of crop).
Phased cropping
phased cropping ►
State TWO advantages of phased cropping,
Area 1
Year
Area 2
^
Area 3
Area 4
*
Fruits
Roots
Legumes
leaves
Fruits
Roots
Roots
Legumes
leaves
Fruits
legumes
Leaves
leaves
Legumes
Year
z
Year
3
Year
4
6
*
Fruits
4
Roots
Figure 12.3 An example of a fouryear crop rotation.
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 fa rmer can maintain a regular supply of
produce to consumers and receive a steady income over time. This type of cropping
prevents an oversupply, or glut, of a commodity which would have the effect of
lowering the price on the market.
Strip cropping and contour cropping
r
strip cropping ►
hl ^'
contour cropping ►
188
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.
1 2 • Crop husbandry
maize (crop)
grass
cabbage (crop)
grass
pigeon peas (crop)
1105
Explain what is meant by contour cropping and
give ONE reason why it is practised on sloping
land.
Figure 12.4 Strip cropping.
Mixed farming
mixed farms ►
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 35) are mixed farms.
Cover cropping
cover cropping ►
Explain why cover cropping is referred to as
green manure.
Practical activity:
Plan a one-year crop rotation
programme using leaf crops,
legumes, root crops and a fruit or
vegetable, such as tomato.
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
ploughed into the soil before the land is re-planted. The cover crop, often referred
to as 'green manure', provides a cover of vegetation for the soil and adds organic
matter when 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, particularly between rows of fruit trees in an orchard.
12.2 Cultural practices associated with crop
production
Many activities (see Table 12.1) 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 Chapter 8.
Cultural
practice
Moulding
Procedure
Benefits
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.
• 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 used
• improves soil fertility
• controls weed growth
189
Section B: Crop Production
Cultural
practice
Staking
t
Give FOUR reasons for staking plan
ning
What are the benefits of mulching?
Procedure
Benefits
A stake is placed beside a
plant; normally round wooden
stakes, 2 m long, 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 8 and
then wound twice around the
stake before tying securely;
tying is done at 20 cm
intervals along the stem.
Dry, diseased or excessive
twigs, leaves and branches of
a plant are removed using a
sharp knife, a pair of secateurs
or a small pruning saw.
• supports plants with weak stems,
e.g. tomato
• 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
Practical activities:
1 Produce a fruit, leaf, flower and
root vegetable crop. During the
sowing, cultivation and growth
of the crop, use appropriate
cultural practices from
Table 12.1.
2. Develop your own notes and
drawings about the production
of vegetable crops.
Irrigating
Applying water to the soil for
the benefit of crop plants; can
be carried out in a variety of
ways.
Fertilising
The application of fertilisers to
crop plants; details of fertilisers
are given in Chapter 8.
• improves the shape of the plant
• encourages growth and
development of fewer, but larger
fruits
• enables air to circulate more
freely in the crop so discouraging
fungal diseases
• prevents spread of diseases to
other plants
• enables good growth and
development
• prevents crop loss through
wilting and death
• helps to regulate supply of soil
water for crops
• promotes growth, development
and production in the crop
• produces healthy plants
• improves and maintains soil
fertility
Table 12.1 Cultural practices involved in crop production.
12.3 The effects of weeds on crops
weed ► A weed is any plant that is growing in the wrong place — or where it is not wanted.
This definition 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 are in competition 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 (e.g. redhead) are poisonous to livestock, especially cattle and
horses which may stray on to the fields.
Why are weeds so successful?
Weeds are successful in competing with crop plants because:
• 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 which will be smaller but still produce seeds
• they produce large numbers of seeds under favourable conditions
190
12 Crop husbandry
• they can often reproduce vegetatively as well as 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 weeds, 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 faster than the crop and smother the crop
seedlings.
Most of the major weed species belong to just a few plant families: the grasses
( Gramineae), the sedges (Cyperaceae) and the composites, such as railway daisy
and red thistle (Compositae). In the Caribbean, annual and perennial grasses,
vines and woody plants can be problem weeds.
Figure 12.5 Nutgrass is a common
Possible benefits of weeds
weed.
What is a weed?
Apart from producing many seeds, how else can
weeds reproduce?
Practical activities:
1. Collect and identify common
weeds.
2. Conduct a weed control trial.
Grow two identical crops under
identical conditions but allow
one crop to become infested
with weeds. Do the weeds
affect the yield?
1
In general, weeds are harmful, but their rapid germination and growth on bare
soil provides a cover of vegetation which can help to prevent soil erosion due to
heavy rainfall.
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 other insects which prey on some crop pests.
12.4 Methods of weed control
It is important to control weeds within a crop to ensure a good yield and good
quality of produce.
Methods of weed control include:
• cultural control — adequate preparation of the land and cultural practices such
as hand weeding and hoeing
• chemical control — the use of weedkillers (herbicides)
• biological control — using other organisms to control weed growth
• integrated control — combining two or more methods which 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 from an authorised supplier will ensure that weeds
are not 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 in weed control. Some weeds are associated with certain
crops and planting different crops in rotation can control a particular weed.
For example, a parasitic weed called Striga affects maize, sorghum and cowpea;
this can be controlled by planting a different crop 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
191
Section B: Crop Production
^
r
ii
Why can buying good quality seed help to con tr ol
weeds?
I
Explain the benefits of hand weeding.
r
When should pastures be mown to control weed
growth?
perennial weeds. It also destroys useful soil organisms. Soil may be ste ri lised
by burning before crop seeds are sown.
• Ploughing will turn the soil over and bury any weeds, but it may also b ri ng
bu ri ed 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
or a cutlass. This is an effective method but it is labour-intensive and timeconsuming. Use of a hoe or a cutlass 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
i mportant 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 ri ce fields. It will get rid of weeds
that cannot tolerate being covered in water.
Herbicides
herbicides, selective herbicides ►
non-selective herbicides ►
pre-emergent herbicides ►
post-emergent herbicides ►
post-maturity herbicides ►
Herbicides are chemicals used to kill weeds. They may be selective herbicides,
killing some plants and not others, or non-selective herbicides, killing 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.
The type of herbicide used depends on:
• 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 only 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
• the stage of growth of the crop: some herbicides are applied before the shoots
of the crop come above the ground (pre-emergent herbicides), some after the
shoots have emerged (post-emergent herbicides), and some when the crop is
mature and just before ha rv esting (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 are usually non-selective and the land is ploughed or harrowed
after the application. Glyphosate and Paraquat are herbicides used in this way and
contact herbicide ► they are effective at controlling annual weeds. Paraquat is a contact herbicide;
when it comes into contact with the leaves it interferes with photosynthesis by
systemic herbicide ► destroying the cell membranes. Glyphosate is a systemic herbicide and works within
the plant. Both these herbicides have no lasting effects in the soil: Glyphosate is
broken down to harmless compounds by soil micro-organisms within a few days
and is not very toxic to mammals. Paraquat is classed as 'moderately toxic' by the
World Health Organisation (WHO).
Selective herbicides
Selective herbicides are used once the crop has been planted. A systemic herbicide
is used, which 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 which kill grass weeds and are also effective against some
broad-leaved weeds.
192
12 •
Crop husbandry
Precautions
When spraying crops with herbicides, protective clothing should be worn and
safety precautions taken to avoid spillage and contamination of other areas. All
the instructions provided for correct application should be followed. If spraying is
on a large scale, then weather conditions need to be considered. It is wasteful to
spray if there is a high wind or heavy rainfall.
Research into the development of new herbicides is taking place all the time, so
it is wise to check with suppliers and extension officers to keep up-to-date.
Explain the difference between pre-emergent and
post-emergent herbicides.
111315
List FOUR factors that a farmer needs to consider
before using a herbicide on the land.
Biological methods
biological methods ►
List FIVE methods of biological control of weeds.
Explain how density of planting of the crop can
affect weed density.
1
Biological methods of weed control involve the use of other living organisms to
control the weeds.
Biological methods include:
• cover cropping: the use of a legume crop, such as mung beans or cowpeas, to
provide vegetative cover has been described on page 117; it prevents growth of
weeds and also adds nitrogen to the soil when ploughed in; the disadvantage
is that the farmer has to purchase the legume seeds
• planting density: the density of the crop will affect the growth of weeds;
the higher the density of the crop, the less room for the weeds; the density
should be adjusted so that crop plants can develop fully but little room is left
for weeds; if the crop density is too high then plants will be small and yield
reduced
• 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; it needs to be carefully controlled and is not
suitable on a small scale. For example, adults of Longitarsus jacobaeae, the
Ragwort Flea Beetle, attack ragwort plants and cause extensive damage. The
beetle larvae intensify this attack by feeding on the roots of this poisonous
weed.
I ntegrated control
integrated control ►
11018
Explain what is meant by integrated control.
Practical activity:
Practise weed control in your
vegetable plot. Try out different
methods. Why works best?
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 nonselective herbicides and ploughing may be the best treatment during 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 and 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.
12.5 Pests and crop damage
A variety of pests (mainly insects) cause damage to crops. Other animal pests
include:
• rodents, such as rats, which damage standing crops and stored crops; rats are
serious pests of sugar cane, gnawing through stems and causing the plants to
fall over; bacteria may get into damaged stems
• birds, which feed on fruit crops, such as grapes, mangoes, papaya and banana,
and damage young seedlings of vegetable crops
• mites, which belong to the same major group as spiders, and feed on the
leaves of crop plants.
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Section B: Crop Production
Insect pests
vectors ►
Insects damage plants by:
• the adults or larvae feeding on the crop
• the adults laying eggs inside flowers, f ru it or stems; when they hatch, the
larvae often feed on leaves and bark, e.g. treehoppers on apple trees
• acting as carriers (vectors) of viral diseases (aphids act as vectors by
transmitting plant viral diseases).
Insects can be divided into two feeding groups:
• the biters and chewers
• the piercers and suckers.
The biters and chewers, such as beetles, grasshoppers, crickets, ants, bees and
wasps, eat their way through plants leaving holes. The larvae of butterflies and
moths (caterpillars) and flies (maggots) are also chewers. By destroying leaves,
these insects reduce the amount of food that the plant can make by photosynthesis,
resulting in poor growth and decreased yield. Often, a severe infestation can
destroy the whole crop.
Sucking insects, such as aphids, have piercing mouthpa rt s which suck sap from
inside the soft tissues of the plants, resulting in reduced growth. The adult stages of
flies and moths are also sucking insects.
Table 12.2 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, p e pp ers , eggplants; can transmit
viral diseases.
Pierces fruits which then drop from trees before
they are ripe, e.g. citrus trees, cashews.
Fruit moth
Fruit fly
White fly
^
Bores into fruits before they ripen, e.g. mango,
pineapple, avocado pear, guava.
Pierces soft tissues so plants do not grow or
thrive, e.g. tomatoes, peppers; can transmit viral
diseases.
Practical activity:
Collect insects and put them into
groups according to whether they
have biting, chewing, piercing or
sucking mouthpa rt s.
i
Cricket
Chews on shoots of young plants, often
destroying the whole plant, e.g. tomatoes,
onions.
Termite
Feeds on the roots and stems, often destroying
whole plants, e.g. grapes.
Weevil
La rv ae tunnel into the corms and cause extensive
damage by weakening the plants so that they are
easily blown down; leaves turn yellow and die,
e.g. banana root borer on bananas.
Diamondback
moth
Larvae (caterpillars) feed on leaves of vegetables,
e.g. cabbage, pak Choi, cauliflower.
Flea beetle
Feeds on leaves leaving round holes, so that
plants have reduced growth, e.g. ochro; can
transmit viral diseases.
List FOUR groups of animals that can be pests of
crop plants.
II
List THREE types of insect pests that can transmit
viral diseases.
194
Table 12.2 Common insect pests of food crops (the pictures are not drawn to scale).
12 • Crop husbandry
12.6 Major crop diseases
Crop diseases can be caused by a number of different organisms. These organisms
pathogenic organisms ► are called pathogenic organisms (disease-causing organisms) and enter plants
through damaged tissues, 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 of
the leaves and wilting.
Table 12.3 summarises some diseases caused by these organisms, their symptoms
and mode of transmission.
Pathogen
Fungi
Bacteria
Viruses
What is a pathogenic organism?
■
Name THREE diseases caused by fungi.
Ira
Mode of
transmission
Spread by spores
in the air which
land on the plant,
germinate and
enter via the
stomata.
Spread from plant
to plant in the air,
in rain or from
contact with other
organisms; enter
the plant via the
stomata or wounds.
Spread by aphids
and other sucking
insects (see Table
12.2); some may
be spread through
budding and
grafting of fruit
crops.
Describe the diseases caused by nematodes.
Mycoplasmas
Spread by
leafhoppers that
jump from one
plant to another.
Nematodes
Abundant in the
soil; can penetrate
and enter roots.
Practical activity:
Make a collection of diseased
plants. Identify the diseases,
noting the symptoms and the
organisms which caused the
disease. Make some drawings of
the diseased plants.
Symptoms of disease
• rusts form reddish patches on the stem
and leaves of cereal plants
• smuts form black powdery masses of
spores which 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 leaves, stems and
tubers of potato
• damping-off disease of seedlings of the
cabbage family causes collapse of stem
tissue
bacterial
wilts produce symptoms which
•
look like a 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 appear 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 the 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 which
are less of a problem than those caused
by fungi, bacteria or viruses)
• causes swelling of roots and root galls
which weaken plants and reduce
growth; affects citrus trees, bananas,
pineapples, grapes, tomatoes
Table 12.3 Some major crop diseases.
195
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Section B: Crop Production
Types of pathogen
fungi ►
bacteria ►
viruses ►
mycoplasmas ►
protozoa ►
nematodes ►
The following groups of organisms can cause diseases in crop plants:
• fungi: organisms that do not possess chlorophyll; consist of a network of
fine threads which spread throughout the plant absorbing nutrients; usually
produce masses of spores (see Figure 12.6)
• bacteria: microscopic, single-celled organisms; obtain their nutrients from the
host plant; multiply rapidly inside the host (see Figure 12.7)
• viruses: very small structures; consist of nucleic acid surrounded by a protein
coat; can only reproduce inside the cells of the host; cannot survive for long
outside another living organism
• mycoplasmas: tiny organisms which are smaller than bacteria
• protozoa: small, single-celled micro-organisms; differ from bacteria in that they
have a true nucleus surrounded by a nuclear membrane (eukaryotic), while
bacteria do not (prokaryotic)
• nematodes: very small (about 1 mm in length), non-segmented worms which
are present in large numbers in soil.
Figure 12.6 Smut on maize — caused by a fungus.
I
Figure 12.7 Bacterial wilt disease on bananas — caused by a bacterium.
196
12 Crop husbandry
12.7 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
Cultural techniques include:
• removal of pests by hand: this is time-consuming but effective for caterpillars
on cabbages; it avoids the use of chemicals which could contaminate 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: reduces the spread of insect pests that infect specific crops
• planting disease-resistant varieties of crop plants: prevents or reduces infection;
disease-resistance can be selected for and many varieties of crop plants are
available (see Chapter 11).
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 (kill weeds), insecticides (kill insects),
fungicides (kill fungi) and nematicides (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 are sprayed on to the crop and they coat the plants. Contact
contact pesticides
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; they
may get washed off by rain so have to be re-applied to control the pest. They
are relatively cheap and effective. Examples: Organochlorines, Pyrethroids,
Carbamates.
systemic pesticides
• Systemic pesticides are absorbed through the leaves and roots of crop plants
and are translocated (carried) around the plant. The cell sap becomes toxic
to the pest which is destroyed as it feeds on the crop. The advantage of the
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:
Organophosphates, some Carbamates.
residual pesticides
• 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.
►
►
►
Biological control
biological control ►
Biological control (see page 193) 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. Nowadays the term is usually reserved for the
deliberate introduction of one species (a predator) to control another species (the
prey). The pest is eaten by the predator.
197
Section B: Crop Production
Biological control is mainly used against insect pests. Other examples of this
predator-prey relationship include:
• control of rabbits in arable crops and pasture by introducing the myxomatosis
virus
• introduction of the Argentinean moth borer to control the growth of p ri ckly
pear on grazing land
• control of mala ria by the introduction of fish to eat the mosquito larvae
• control of stem borer in sugar cane by introducing wasps from India, Apanteles
flavipes and Paratheresia, and the Cuban Fly, Lexophaga.
tHow does crop rotation help in pest and disease
management?
i^..
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. Numbers of pest insects and
predators will fluctuate 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
pest of cucumber, is readily controlled by the tiny wasp Encarsia formosa.
Natural predators of insects are often found on vegetation bordering field plots;
such 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 required.
Explain the difference between contact and
Integrated pest management (IPM)
systemic insecticides.
integrated pest management ► 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
Explain the principles involved in the biological
control of pests.
i
/
Where has biological control of pests been most
successfully used? Why is it so successful?
Practical activities:
1. During your cultivation of a
vegetable crop, use some
appropriate methods to control
pests and diseases. First you
need to find out what the
common pests and diseases
}
)
4
are and investigate the best
methods of dealing with them.
2. Carry out an Internet search for
198
information on crops that can
deter insect pests,
on chemicals.
If pesticides are used, they should be chosen for their sho rt -term toxicity (so
that they break down to harmless substances in a sho rt 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 following cultural and biological control methods.
12.8 Chemicals in the environment
There is widespread use of chemicals in the form of pesticides, weedkillers and
artificial fe rtilisers. Using chemicals brings obvious advantages to the farmer and
the consumer, but there are also disadvantages. Many scientists are concerned that
agricultural chemicals are damaging our environment.
Advantages of using agricultural chemicals
The advantages include:
• the effects of application may be seen relatively quickly: pests and weeds can
be destroyed before they cause much damage to the crop
improved crop yields: crops benefit from the removal of weeds and pests and
will grow better; farmers make more profit; there is a better supply of good
quality produce for the consumer
• pest and weed control takes less time: manual and cultural methods are more
time-consuming and labour-intensive; the farmer who uses chemicals has
more time for other operations
• a longer storage life for food: better quality produce will be produced, which
will last longer.
12 Crop husbandry
Problems with agricultural chemicals
For some time, there has been concern about agricultural chemicals that get
into the environment. Chemicals applied to the soil or sprayed on to crops can
be leached by rainwater into rivers and eventually into the oceans. Excessive
use of chemicals can cause pollution and affect the plant and animal life of both
freshwater waterways and the oceans. Chemicals may build up in organisms (such
as shellfish) — these chemicals are subsequently eaten by other animals higher up
the food chain. The chemicals get concentrated in these animals and sometimes
kill them.
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, blocking
sunlight from other aquatic plants.
When the algae die, they are
broken down by bacteria which use
up oxygen in the water. Because
artificial fertilisers increase numbers
of algae and bacteria, the water
deoxygenated ► becomes deoxygenated (lacking in
oxygen). As a result, other aerobic
organisms in the water, such as Figure 12.8 An algal 'bloom' — oxygen
insects, insect larvae and fish, will levels will be reduced in the water.
suffocate and die.
eutrophication ►
This increase in nitrates and phosphates in the water is called eutrophication.
Eutrophication can also occur if there are sewage spills or a run-off from farm
manure, as these contain nitrates and phosphates.
Pesticides
DDT ►
Explain what is meant by eutrophication and why
it causes problems to the environment.
Describe how toxic chemicals can enter food
chains and affect the top carnivores.
Pesticides can also get into waterways, either as drift from crop spraying or
from being washed off plants and down through the soil by rain. The toxicity of
pesticides and their effect on crop plants has to be thoroughly investigated before
the pesticide can be marketed. Sometimes chemicals produced when the pesticides
break down may affect other organisms in the environment.
DDT is an example of how a pesticide can affect other organisms. This is a contact
insecticide that had been 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
soil into rivers and been absorbed by small organisms, which were 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 numbers of these birds. The use of DDT was
banned worldwide in the early 1970s.
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 which break down more readily. In addition, pesticides are being
developed to target specific pests.
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Section B: Crop Production
Pesticide labelling
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 are 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,
emergency and first aid treatment
• reference to physical, chemical and environmental hazards
• directions for use
• storage instructions.
t i
When using a pesticide, why is it important to
follow carefully the instructions for use?
Practical activities:
1. Find examples of pesticide
labels and interpret the
information on them.
2. Draw up a list of rules for
the safe handling, storage
and disposal of chemical
containers.
Give THREE reasons why it is important to keep
records of crops planted.
I11
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.
12.9 Cultivation of vegetable crops
Keeping records
Individual crops have different requirements and need therefore different
treatments.
When growing different crops, it is useful to keep records of the following:
• the crop name and variety chosen
• how the land was prepared
• the type of material planted: seeds, seedlings, cuttings, tubers, rhizomes,
suckers, bulbs
• date of planting
• fertiliser treatment: type, quantity and rate of application
• methods of weed control used
• pests and disease control if needed: type of pest or disease; treatment given
• cultural practices: irrigation, drainage, moulding, mulching, pruning, staking,
intercropping
• harvesting: date of harvest; yield
• post-harvest handling: trimming, washing, grading, weighing, packaging,
storage
• marketing: pricing, labelling, selling
• economic value: calculate total inputs and work out profit or loss.
Such records are essential to a farmer and help him to calculate income (see
Chapter 7). They are also helpful as a reference for future enterprises and help th
farmer to decide what crops and varieties to grow, what will thrive on his land, an
what treatments are most successful. On a smaller scale, it is interesting to compar
the yield from different varieties and the effectiveness of different fertilisers an
pesticides on crops grown in vegetable plots or containers.
t
e
J
e
12 • Crop husbandry
Accessing information
The farmer needs to be able to access useful information about crop cultivation procedures. Below are some examples of
information relating to cultivating four different crops.
Example 1: Cultivation of a fruit vegetable crop, e.g. tomato (Lycopersicum esculentum)
Crop varieties: Calypso, Floradel, Cascade, Heatmaster, Gem Pride, Kada, Nema, Tropic Boy
• Land preparation: soil prepared to a fine or medium filth; dig box drains; make raised, flat-topped or cambered
beds 1 m wide and 4 m long; spread evenly and then incorporate pen manure or compost into the soil; apply a
soil pesticide mixture containing 10 ml Diazinon (insecticide) and 30 ml Tri Miltox (fungicide) in 4.5 1 of water;
Nemagon or Vidate L can be applied to control root-knot nematodes.
• Planting material: hardened seedlings, 3-4 weeks old.
• Planting distance: seedlings transplanted 45 cm apart and 60 cm between the rows.
• 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. NPK (13:13:20) or (12:12:17) can be applied at the rate of 45 g per plant and
repeated at 3-week intervals. A blossom booster, Nutrex NPK (10:20:30), is applied as a foliar spray at weekly
intervals, beginning two weeks after planting.
Weed control:
• weeds can be removed by uprooting or with a hoe at least twice; 2-3 weeks after planting and then 3 weeks later.
Pest and disease control:
• for mole crickets, slugs and cutworms, apply a soil insecticide, such as Diazinon; 10 ml per 4.5 1 of water
• for leaf attack by caterpillars and aphids, use Pestac; 5 ml per 4.5 1 of water
• for leaf miner attack, apply Trigard as a foliar spray
• for fungal attack, use Champion, Kocide 101 or Tri Miltox
• for blossom-end rot; water the soil regularly.
Cultural practices:
• Irrigate the crop regularly.
• 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 lightly till the soil for aeration and weed control.
• Apply mulch in the dry season.
Harvesting: first fruits are ready for harvesting 2 to 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 beans, sweet peppers, hot peppers, cucumbers and okro. Cultivation details vary
slightly, particularly with respect to pest and disease control and harvesting.
Example 2: Cultivation of a root crop, e.g. yam (Dioscorea)
Crop varieties: White Lisbon, Yellow Lisbon, Chinese, Cush Cush
• Land preparation: land ploughed to depth of 30 cm and soil rotavated to a medium tilth. NPK (10:20:10) fertiliser
is broadcast at the rate of 200 g per square metre (m 2 ) and incorporated into the soil. Furadan granules (45 g/m2)
are broadcast and incorporated into the soil to control nematodes and other pests. Banks or ridges 30-45 cm high
and 90 cm apart are formed.
• Planting material: usually small whole tubers are used, or large yams can be cut into pieces about 150-200 g each.
There needs to be skin on each piece, otherwise they will not germinate.
• Planting distance: tubers planted to a depth of 7 cm, 30-45 cm apart in the row. There should be 90 cm between
the rows. Planting usually takes place in early May.
201
Section B: Crop Production
• Fertiliser application: apply NPK (10:20:10) at a rate of 45 g/plant about 2 months after planting. Drill or place the
fertiliser beneath the soil to reduce loss of nutrients. Make three similar applications of the same fertiliser, using 60
g/plant every two months.
Weed control:
• after planting, apply a pre-emergent weedkiller, such as Gesaprim, using 30 g/4.5 1 of water. Later, weeds can be
controlled by hand weeding or by the application of Gramoxone (60 ml/4.5 I water) with a shield between rows.
Pest and disease control:
• for caterpillars and leaf-eating pests, use an insecticide such as Decis (10 ml/4.5 I water)
• for fungal leaf spots, use Kocide 101 or Tri Miltox (30 g/4.5 1 water)
• for nematodes, Furadan granules can be applied at land preparation and Vydate L (10 ml/4.5 I water) can be used
4-6 months after planting
Cultural practices:
• Ensure that the field is well-drained.
• Stake yams to increase leaf exposure for photosynthesis so that crop yield is improved.
F
t 1
t
Harvesting: yams are harvested 9-12 months after planting. The tubers are carefully dug out using a straight cutlass
or luchette, without damaging or bruising yams.
Post-harvest handling: wash and air-dry the yams, pasting any cut or damaged surfaces of tubers with ground
li mestone 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 potatoes, carrots and cassava.
Example 3: Cultivation of a leafy crop, e.g. 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: hardened seedlings about 3 weeks old.
• Planting distances: transplant seedlings 25 cm apart in the row and 25 cm between rows.
• Fertiliser application: apply 10 g sulphate of ammonia per plant one week after planting, then 15 g after two
weeks. Dissolve 10 g Nutrex (NPK 20:20:20) in 4.5 1 water and apply as a foliar spray once a week.
Weed control:
• uproot weeds as they appear. Light tillage helps to aerate the soil and control weeds.
Pest and disease control:
• for leaf attack by aphids and caterpillars, apply an insecticide, e.g. Pestac (5 me in 4.5 Q of water)
• for fungal attack, use a fungicide such as Champion (30 gin 4.5 f of water)
Cultural practices:
• Water or irrigate the crop regularly.
• Lightly dig up the soil surface for aeration and weed control.
• Mulch in the dry season.
Harvesting: lettuce heads are ready for harvesting in 4 to 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 which 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.
202
12 Crop husbandry
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 (patchoi), spinach and seasoning herbs.
Example 4: Cultivation of a vegetable flower crop, e.g. cauliflower (Brassica oleracea)
Crop varieties: Kono 45, Early Market, Snow 55, Early Patna
• Land preparation: same as for lettuce and tomato.
• Planting material: hardened seedlings about 2-3 weeks old with 5-6 leaves.
• Planting distances: 50 to 60 cm apart and 60 cm between the rows.
• Fertiliser application: ideally, cauliflowers should be grown as part of a crop rotation and would follow a legume
crop; NPK (20:20:20) used alternately with urea for 6-8 weeks after planting, followed by NPK 12:12:17 and/or
NPK 13:13:20 for the development of heads (flowers); acid soils need liming.
Weed control:
• hoe regularly to remove weeds.
Pest and disease control:
• for leaf attack by aphids and caterpillars, apply an insecticide
• for fungal attack, use a fungicide
• for club-root prevention, soil should be limed and well-drained; if diseased plants appear they should be removed
and burnt; Brassicas should not be planted in the plot for several years
• for protection from birds, use a net or bird-scarer.
Cultural practices:
• Water or irrigate the crop regularly.
• Bend a few leaves over the developing curd to protect from the sun.
• Mulch in the dry season.
Harvesting: heads are ready 14-16 weeks after planting. Cut heads,
preferably in the morning, using a sharp knife. Place in crates.
Post-harvest handling: Trim outer leaves, but leave those immediately
around the curd. Place in trays or baskets and store in a cool place.
Marketing: grade heads according to size and place in clear polythene bags.
Cauliflower is boiled and used as a vegetable. It contains some minerals and
vitamins.
Practical activities:
1. Make your own records by
recording the production of
your vegetable crops.
2. Prepare a cost analysis of ONE
of the crops cultivated.
12.10 Plant quarantine
alien pests, alien diseases ►
Alien pests and alien diseases are pests and diseases which do not occur naturally
in a country. Their introduction into a country can cause much damage. With an
increase in world trade, much agricultural produce is now exported and imported.
Crops are transported by air and can reach their destination in hours. In most
countries, strict regulations ensure that only the highest quality pest-free produce
is exported and that all imported goods are inspected.
The introduction of alien pest species, such as weeds and insects, could cause
havoc to agricultural production in that country. 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.
In most countries, there are restrictions on the importation of plant material. It
can only be imported with permission and from accredited suppliers. All imported
material is inspected at the point of entry. Even the baggage of passengers entering
the country is inspected and any unauthorised plant material may be confiscated.
203
Section B: Crop Production
Explain the importance of plant quarantine
regulations.
In the USA, regulations stop the movement of certain crops from one state tc
another to control the spread of pests.
Quarantine centres are established by the Ministry of Agriculture at airports anc
ports and employ qualified personnel to carry out inspections. Each territory in the
Caribbean has its own regulations and operates its own quarantine centres.
Practical activity:
Visit a plant quarantine station.
P
rr
E
204
• Many cropping systems are available to farmers; they choose systems to sui
their land and size of farm.
• Monoculture is the cultivation of one single crop on a plot of land which take:
up a large area. A good example is sugar cane.
• Mixed cropping and intercropping allow the cultivation of more than one crof
at a time.
• Other types of cropping include phased cropping, crop rotation and stril
cropping.
• Strip cropping and contour cropping can be used on hilly terrain where there i:
danger of soil erosion.
• Cultural practices are focused on obtaining the best yield whilst maintaining
soil fertility. They include moulding, mulching, pruning, staking, fertilising an
irrigating.
• A weed is any plant that is growing where it is not wanted.
• Weeds deprive crop plants of space in which to grow, water and nutrients.
• Weeds compete with crop plants as they grow quickly, produce masses of seed
and the seeds may be spread over a wide area. The seeds remain viable in thi
soil for a long time.
• Weed control can be achieved by cultural, chemical and biological methods
Integrated control is a combination of several methods.
• Cultural methods are aimed at cultivating the land so that weeds are remove(
by mowing, ploughing and mulching.
• Chemical control is achieved by weedkillers (herbicides).
• Herbicides can be contact herbicides, which destroy weeds when sprayed of
to them, or systemic herbicides, which are taken up by the roots of weeds any
translocated around the plant.
• Selective herbicides kill specific weeds such as broad-leaved weeds in maize.
• Biological control of weeds can be achieved by crop rotation, cover cropping a
introducing a pest of the weed species.
• Crops can be damaged by animal pests such as rats, birds, insects and mites.
• Insect pests are grouped into biters, chewers, piercers and suckers, according t.
their method of feeding on the crop plants.
• Many insect pests can also transmit (act as vectors for) viral diseases.
• Crop diseases can be caused by fungi, bacteria, mycoplasmas, viruses, protozo
and nematodes.
• Control of plant diseases can be achieved by cultural, chemical and biologic
methods. An integrated approach is a combination of methods but with th
emphasis on minimal use of chemical pesticides.
• Chemicals used in farming can cause eutrophication of waterways and harr
wildlife. Toxic chemicals can get into food chains and damage organisms.
• Pesticides have to be labelled and include safety precautions which should b
followed when applying them.
• It is important to keep records of crops grown so that income can be calculate
and harvesting times predicted, and so that comparisons can be made from yez
to year.
• Plant quarantine protects a country from pests and diseases being brought in.
• Foreign pests and diseases could seriously affect crop production.
12 Crop husbandry
•to
rid
lie
31.
IT01
Any four from: monoculture, strip cropping, multiple cropping, contour
cropping, crop rotation, phased cropping, mixed farming, organic farming,
intercropping.
ITQ2
Advantages: farmer can concentrate on the production of one crop;
farmer has specialised machinery to deal with crop; disadvantages: it can
lead to a build-up and rapid spread of pests and diseases.
ITQ3 Multiple cropping refers to the cultivation of two or more selected crops
itit
on the same plot of land simultaneously. Intercropping is when a shortterm crop is grown between the plants of a medium-term crop.
ITQ4 There is continuous cropping so that the farmer can maintain a regular
ces
supply for the market. There is a steady income from this type of
cropping.
op
ITQ5 The land is ploughed along the contours and crops are planted. It helps to
prevent soil erosion and improves drainage.
rip
is
ng
nd
11106
Often a cover crop of a legume is planted and then ploughed in, adding
nitrogen to the soil.
ITQ7
Staking supports plants with weak stems, enables plants to grow upright,
keeps fruit above the ground and it makes it easier for weeding and other
cultural practices.
ITQ8 Mulching conserves soil water, prevents weed growth, contributes to soil
fertility and adds organic matter.
ITQ9 A weed is any plant that is growing where it is not wanted.
ds
ITCH 0 They can reproduce by means of underground stems and rhizomes.
IT011 Good quality seed does not contain weed seeds so the density of planting
Is.
will not be affected and there will be little room for weeds to grow.
ITI312 Hand weeding can get rid of small weeds without disturbing the crop
plants. If done carefully, weeds with tap roots can be completely
uprooted.
IT013 It should be done when the weeds are mature but before they have
produced flowers and seeds.
id
ITC114 Pre-emergent herbicides are applied to the crop before the shoots come
above the ground, whereas post-emergent herbicides are applied after the
shoots come above the ground.
11015 The state of the land; the type of crop; the stage of growth of the crop; the
type of weed.
0
11016 Cover cropping; density of planting; choice of crop; grazing; introduction
of a pest of the weed species.
IT017 The higher the density of the crop, the less room there is for weeds to
a
it
e
r
grow.
111:118 Integrated control means using a combination of methods to control the
weeds, e.g. non-selective herbicides, ploughing, hand weeding.
IT019 Four from: rats and mice; birds; insects; nematodes; mites.
ITQ20 Aphids, white fly and flea beetle.
11'021 A pathogenic organism is one that causes a disease.
ITQ22 Rusts, smuts and powdery mildews.
ITQ23 Cause swellings of roots and root galls that weaken plants and reduce
growth.
11024 By growing different crops in rotation, the build-up of specific pests is
reduced.
205
Section B: Crop Production
11025 Contact pesticides coat the plants and get into the bodies of the pest
organisms. Systemic pesticides are taken up by plants and the cell sap of
the plant is toxic to the pest.
11026 Biological control of pests is based on the introduction of a predator of the
pest organism.
11027 Biological control has been most successfully used in the control of pests
in greenhouses where conditions are controlled and the pest and its
predator are confined.
11028 Eutrophication is the enrichment of water in rivers and lakes by the runoff from agricultural land which contains nitrates and phosphates. The
growth of algae is encouraged and their decay uses up oxygen in the
water so that other organisms, such as fish, die.
11029 Toxic chemicals can be eaten by small organisms. The small organisms
are eaten by larger organisms and they accumulate the chemicals in their
tissues. Toxic chemicals are found in the top carnivores in significant
concentrations and can affect them, e.g. thinning of the shells of birds so
that no young are produced. The chemicals do not break down quickly,
i.e. they persist in the soil or water.
11030 So that the correct quantity is used, it is used in the correct concentration,
it is used at the right time, and so that all the safety precautions are
followed.
11031 Helps to calculate income; helps to predict harvesting dates; records
the effects of different fertiliser treatments and application of pesticides;
compares the yield from year to year; compares different varieties of crops.
11032 Plant quarantine regulations prevent any pest or disease entering a
country or region. They make sure that exported plant material is free
from pests and diseases.
Examination-style
questions
206
Multiple Choice Questions
1. 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
2. Soil can be conserved on sloping land by:
A contour cropping
B intercropping
C phased cropping
D monoculture
3. Mulching is a cultural practice which:
A prevents the spread of diseases to other plants
B supports plants with weak stems
C aerates the soil
D improves soil fertility
4. 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.
12 • Crop husbandry
re
1
5. 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.
6. Viral diseases can be spread to crop plants by:
A moth larvae
B aphids
C termites
D weevils
7. Mosaic diseases of crop plants are caused by:
A fungi
B bacteria
C viruses
D nematodes
8. 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 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.
207
V.
IIIIItIllun..-
- ------
...............
V estio
9
postharvest
and
a
practices
By the end of
this chapter
you should be
able to:
3
/
/
explain what is meant by post-harvest technology
describe the stages of maturity at harvest of a range of crops
describe appropriate harvesting methods for crops
/
3
explain what is meant by post-harvest technology
describe how the flowers of heliconia, orchid, ginger lily and anthurium
are harvested
explain the post-harvest practices for these flowers
understand the post-harvest operations which take place from the
farm to the table.
3
3
Concept map
Harvesting and
post-harvest practices
Stages of maturity at harvest I
Harvesting
Methods
I
I
IN
Post-harvest operations
From farm to
table
Timing
egg plant
ochro
208
I
bodi beans
I
banana
For
ornamentals
corn (maize)
pawpaw
' 3 • Harvesting and post-harvest practices
13.1 Post-harvest technology
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 correct storage conditions can
prevent wastage. This will increase profits for the farmer.
Poor handling of crops after harvest causes a loss of produce that has taken time,
labour and materials to cultivate. The economic consequences can be serious,
particularly if produce has to be transported any distance. There is less wastage
if produce is grown and consumed locally, as there is less time for deterioration.
Post-harvest technology needs to be applied if fresh produce is grown at a distance
from where it is consumed.
When to take special care
1
What is post-harvest technology?
▪
Why is appropriate packaging necessary for
crops?
Care needs to be taken during:
• harvesting: so that crops are not damaged by bruising or cutting
• cleaning, grading and packaging: careful handling will prevent bruising
• storage before being taken to market: cool conditions will slow ripening and
prevent dehydration
• transportation: proper packaging will prevent damage; refrigeration is needed
for perishable produce
• long-term storage: cereals and other produce stored for long periods need to
be stored under the correct conditions to prevent damage by pests.
13.2 Harvesting crops
Signs of maturity
The useful and edible parts of crop plants are harvested at the desirable stage of
maturity and this varies according to the type of crop.
Maturity is related to age of the crop and may be associated with:
• changes in colour
• the drying up of stems and leaves
• characteristics linked with marketability, processing and use.
mature
►
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.
Signs of maturity include:
• tomato: fully mature stage; browning in the region of the calyx
• yam, eddo: fully mature stage; die-back or drying of the aerial stem and leaves
• avocado, guava: fully mature stage; changes in skin colouration, from dark
green to yellowish-green
• banana (for export): 75% full (mature) or 75% fully-developed stage
• bodi beans, ochro, loofah: snap stage
• cucumber, spinach, eggplant (melongene): succulent (juicy and not too
fibrous) stage
• coconut (water nut): soft/medium jelly stage
• melon, pawpaw, pumpkin, citrus, hot pepper: ripe or ripening stage
• paddy (rice), corn (maize), coconuts: dry stage
• egg plant, gourd: soft, plump stage.
The timing of harvesting
The timing of harvesting depends on several factors as listed below.
• The age of the crop: this can be calculated using the date of planting and serves
as a harvesting guide for the farmer. The period from planting to harvest for
209
Section B: Crop Production
List the FOUR major factors that determine the
ti ming of harvesting.
At what stage of maturity should bodi beans be
harvested?
some crops can be relatively short (lettuce — 6 weeks, cabbage — 3-4 months),
but for others the wait is much longer (bananas — 9 months, cassava — 6 to 12
months depending on the cultivar).
The type of crop: some crops, such as lettuce, dry-corn and rice, are harvested
all at once, making way for a new crop to be planted. Tomatoes, bodi beans,
ochro and hot peppers produce fruit continually for a period, even after a first
harvest. These crops need to be harvested regularly as 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 to 3 days, bodi beans —4
to 5 days, spinach — 6 to 7 days and karaile — 5 to 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, making it easier
for harvesting rice, corn and sugar cane. Dry weather makes harvesting
operations using machinery easier as the soil is dry.
13.3 Harvesting methods
Harvesting methods used vary according to the crop and the cropping system
under which it was grown. All methods should be carefully carried out to ensure
that produce (plant parts) being harvested is not damaged.
Manual harvesting is used for cocoa, coffee, bananas and yams. Mechanical
harvesting, by mean of combine harvesters, is used for rice, corn and sugar cane.
Manual harvesting methods
Figure 13.1 Harvesting sugar cane by
hand.
These methods include hand-picking, uprooting, the use of a knife or a cutlass,
or digging out with a fork. They are used for crops grown in small plots, using
multiple cropping or intercropping systems and where fields are not accessible to
machinery.
Manual methods (see Table 13.1) include:
• nipping-off with the thumb and index finger: bodi beans, cucumbers, karaile,
hot peppers, string beans
• 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, melongene, sweet pepper
• cutting stalks with a sickle and threshing the grains: rice (paddy)
• cutting stalks with a cutlass: sugar cane
• hand picking: tomato, mango, guava, citrus, maize
• picking with a goulet: cocoa, breadfruit, breadnut
• using a fruit-picker: avocado.
Crop
Stage of maturity
Method of
harvesting
Ochro
• snap stage: tip end
snaps or breaks
easily
• 10 -15cm long
(average)
• snap stage
• prominent
indentations on pods
• cut pedicel
(flower stalk)
with a sharp
knife or
secateurs
• nip off pedicel
using thumb
and index
finger
• hand-picking of
fruits carefully
Bodi beans
Tomato
210
• brownish around the
calyx (sepals)
Timing Of
harvesting
• every 2 -3 days
•
5 -7 day
intervals
• every 5 -7 days
13 • Harvesting and post-harvest practices
Practical activities:
1. Harvest the crops planted in
Crop
Stage of maturity
Corn (maize)
green
• light golden-coloured
grains
Melongene
(egg plant)
• soft, plump fruits
• 25-35cm long
(average)
• drying or 'dieback'
of aerial stem (vine)
and leaves
the practical activity suggested
for Chapter 12 on page 190
using appropriate methods.
Remember to record the yields
of the harvested crops for your
Yam
records.
2. Hold an Open Day to market
shod of
harvesting
• break-off or
pluck-off cobs
from the corn
stalks
• cut pedicel with
a sharp knife or
secateurs
• dig out tubers
the produce grown.
Pawpaw
Banana
Which crops can be harvested mechanically?
• ripening of fruit
• yellowish green
or orange-green
colouration
• 75% full or 75%
fully developed fruits
• cut pedicel with
a sharp knife or
secateurs
• cut-off bunch
with a cutlass
• dehand, using a
sharp knife
liining Of
harvesting
• 3-5 day
intervals
• every 5-7 days
• 9-10 months
after planting
• by midApril, before
sprouting
• 6-9 months
after planting
• every 5-7 days
• 8-10 months
after planting
Table 13.1 Stages of maturity, methods A harvesting and timing of harvesting for
Why are manual harvesting methods necessary in
multiple cropping and intercropping systems?
some crop plants.
Mechanical harvesting methods
Machines for mechanical harvesting speed up the process of gathering in a crop,
saving time and manual labour. The simplest types of machines can be attached to
a tractor, such as the sweet potato harvester. This is designed to dig the tubers and
lift them from the soil on to a conveyer belt.
Combine harvesters are used for grain crops. They cut the crop, thresh and
winnow the grain. The grain is gathered into trailers and is transported away for
storage. Sugar cane can also be harvested by specially designed combine machines.
Mechanical harvesting methods are common on large farms where fields are
easily accessible. It saves time and labour, although the cost of machinery is a
drawback.
There are problems associated with using heavy machinery in poor weather
conditions or where the terrain is hilly. Harvesting methods have to be adapted to
the crop, the nature of the farm (small, medium or large, on hilly terrain or flat),
and weather conditions.
Figure 13.2 Machine harvesting: this
machine harvests sweet potatoes.
13.4 Harvest and post-harvest practices for
ornamentals
Ornamental crops need special harvesting techniques and post-harvest treatment
to ensure they reach the market in prime condition. Chapter 21 has more
information on ornamentals.
Anthurium (Anthurium genus)
Depending on their size at planting, suckers produce flowers in 3 to 6 months.
spathe ► Hybrids may produce 12 flowers per year. Flowers are harvested when the spathe
(the hood-like leaf surrounding the spadix) is fully opened, the flower stalk is firm
spadix ► up to the bloom and the spadix (candle) is firm and rough with prominent seed
buds. Using secateurs, blooms are cut with a stalk length 40 to 80 cm and placed
upright in baskets.
211
Section B: Crop Production
Post-harvest handling: flowers are stored in a cool area, graded according to size,
colour and injury; then they are packed in boxes.
Heliconia (Heliconia genus)
Heliconia plants produce blooms 9 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 2 leaves on the flower stalk. The
blooms are placed in a basket with flowers protruding upwards.
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 6, and covered with
clear polythene for the local market.
Figure 13.3 An anthurium flower.
Explain why cut flowers should be kept cool.
Practical activity:
Visit flower shows, or farms where
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
into special orchid tubes filled with water to support the
stems. They are packed in boxes and stored in a cool
place.
ornamentals are grown. Ask about
the post-harvest treatment of the
blooms that are grown.
perishable ►
13.5 From the farm to the table
The quality of produce can only be maintained and not
Figure 13.4 A ginger
improved by post-harvest operations and most fresh lily flower.
produce is highly perishable (this means that it will decay
quickly). Harvested produce generates heat through
respiration and loses moisture rapidly, causing wilting and shrivelling. Fruits such
as bananas release ethylene gas which causes ripening so the presence of a few
ripe bananas can bring about ripening in other fruits. 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.
Post-harvest and harvesting techniques
FIX
fi
The following techniques can help in producing high quality produce.
• Harvesting early in the morning or late in the evening and when the weather
is cool or cloudy.
• Pre-cooling 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.
• Careful packing to avoid bruising and damage; avoid rough handling during
packing, loading and unloading.
• The use of large baskets, trays and crates for packing.
212
13 Harvesting and post-harvest practices
0
When should harvesting of produce take place?
Give reasons for your answer.
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.
• Avoidance of movement during transportation by securing containers firmly
( movement could damage and bruise the produce).
• Storage of produce at the recommended temperatures.
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. The 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.
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Post-harvest technology refers to processes which have been developed to
handle, store and market produce after harvesting.
Harvesting occurs when the edible parts of plants are at a desirable stage of
maturity. This varies with the crop.
Some crops, such as tomato, yam, cucumber and melon, are harvested at the
ripe or fully mature stage.
The timing of harvesting depends on the age of the crop, type of crop, maturity
of new produce and the weather.
Some crops, such as lettuce, are harvested in batches; others, such as tomatoes
and beans, produce fruit continuously over a period of time.
Harvesting methods may be manual or mechanical.
Manual methods include hand picking, cutting stalks with a knife and digging
up roots.
Manual methods are used on small farms or vegetable plots or for intercropping
systems.
Mechanical methods are used for rice, other cereals and sugar cane. They use
combine harvesters and 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.
Blooms, such as anthurium, ginger lily and heliconia, are cut with secateurs
and kept cool to prevent wilting.
Post-harvest treatment of produce prolongs shelf life, gives more time for
transport and processing and brings profit for the farmer.
Harvesting should be done when it is cool, early morning or late evening.
Produce should be kept cool.
Rough handling during any stage of post-harvest operations should be avoided.
Produce is washed, trimmed and graded before being marketed. Perforated
polythene bags may prolong freshness.
213
Section B: Crop Production
1101 Post-harvest technology refers to processes used when handling, storing
and marketing produce after it has been harvested.
IT02 Packaging is needed to prevent the produce from becoming damaged or
bruised, and to keep it in good condition for as long as possible.
1103 The age of the crop, the type of crop, the maturity of the new produce
and the weather conditions.
1104 Bodi beans should be harvested at the snap stage.
ITQ5 Sugar cane, rice and cereals.
1106 The areas planted with each crop are small; crops will be in isolated rows;
such systems are often used on hilly terrain unsuitable for mechanical
harvesters.
1107 They should be kept cool to slow down respiration and to prevent loss of
too much water by evaporation.
1108 Early morning or late evening, or when there is cloud cover; to
prevent heating of the produce and avoid wilting and loss of water by
evaporation.
1109 Produce should be handled carefully while being harvested; packed into
crates, boxes or baskets for removal from the field; securely packed during
transport to market.
Examination-style
questions
Multiple Choice Questions
1. Sunny weather is best for harvesting:
A tomatoes
B sugarcane
C beans
D sweet peppers
2. Mechanical harvesting is usually used to harvest:
A corn (maize)
B radishes
C citrus
D melons
3. 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 which 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. (a) List THREE principles of post-harvest management.
(b) Describe in detail ONE principle you have listed for (a).
(c) Describe the techniques farmers should adopt in the post-harvest
handling of tomatoes.
214
13 • Harvesting and post-harvest practices
7
6. Complete the table: listing ONE recommended variety and the nutritional
value of each crop.
Name of crop
One recommended variety
Nutritional value
cassava
cucumber
pak choi
pumpkin
pigeon pea
7. Describe how you would prepare blooms from a named ornamental for
market.
8. A farmer wanted 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, and
(c) the post-harvest processes needed for these vegetables.
215
Iliipiii
1111^u^ununu..■ ...................
I
j°`
_
Processingand
By the end of
/ state the reasons for the processing of crops
this chapter / describe the various types of processing techniques
you should be ,/ develop a processed product from a cultivated crop
able to:
/ suggest how food and non-food processed products may be used.
Concept map
Processing and utilisation
Reasons for
processing
Use of processed
product
Techniques
Preservation
Refrigeration
Conversion
into another
product
Freezing
Heat
Extraction of
a product
canning
pasteurisation
UHT
jam-making
Drying
Freeze-d ry ing
Fermentation
sauerkraut
soya sauce
wine
beer
coffee
216
Food
l
No n-food
14 • Processing and utilisation
14.1 Reasons for processing crops
Crops are processed to:
• preserve them
• convert them into another food product
• extract a product from them.
Preservation
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 works for months or years.
Micro-organisms can be killed by heat, or their growth is 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.
Conversion into another food product
Food processing often involves turning foods into other food products.
• Cereal grains are processed into flour for baking, breakfast cereals and feed for
animals.
• Grains are also processed during the production of beer.
• Grapes are processed to make wine. Apples can be converted into cider.
• Fresh fruit and vegetables are used in the preparation of a wide variety of
products and cooked dishes. For example, tomatoes may be processed into
tomato juice, tomato puree, tomato sauce, soups and cooking sauces.
Extraction of a product
Give THREE reasons why crops are processed.
Explain how micro-organisms cause spoilage of
fresh produce.
Sometimes a food product has to be extracted from the food source.
• Sugar cane has to undergo processing before the product can be used. The
stems contain a sugary sap which must be extracted before it can be processed
into sugar.
• Some plants, such as olives, sunflowers and rape, are grown for their oil. The
fruits or seeds are harvested and the oil is extracted by pressing.
14.2 Food processing techniques
Food processing techniques include:
• the use of heat
• refrigeration
• freezing
• drying
• fermentation.
Heat
blanching ►
Short-term preservation of food can be achieved
by blanching, which involves plunging the
food into hot water for a few seconds to a few
minutes. Micro-organisms on the surface may be
destroyed and enzymes within the tissues of the
food will be inactivated. Blanching is used to treat Figure 14.1 Blanching
fruit and vegetables before they are processed. vegetables.
217
Section B: Crop Production
Further processing may involve freezing, drying or canning, or to preserve their
colour. Blanching does not significantly alter the texture or taste of the food.
cooking ► Cooking can preserve food in the short term. The food is heated to a high
temperature for a short period. The temperature within the food reaches 70°C,
which is high enough to destroy most micro-organisms. Cooking alters the texture
and colour of fruit and vegetables, making them softer. Cooked food, if not eaten
straightaway, can be cooled, refrigerated and kept for a few days; or they can be
frozen and kept for longer.
Pasteurisation
pasteurisation ► Heat is also used in pasteurisation. Pasteurisation is used to treat milk, but also in
the short-term preservation of fruit juices and other foods. In the process, food is
heated to 72°C for 15 seconds, cooled and then packed into sterile containers or
cartons and sealed. The cartons are refrigerated before use. Once a carton has been
opened and exposed to the air, the contents need to be consumed within a few
days. Pasteurisation destroys pathogenic micro-organisms, but does not alter taste
or the nutritional content.
UHT treatment
UHT (Ultra High Temperature) ► UHT (Ultra High Temperature) treatment involves heating food to a much higher
temperature, 132°C, for a few seconds, placing it in sterile cartons and sealing. With
this treatment, the product can be kept without refrigeration for several months.
However, once opened, the contents should be used within days. Foods preserved
in this way include milk, fruit and vegetable juices.
canning ►
rK
Explain how heating can help to preserve food.
jam-making ►
Distinguish between pasteurisation and UHT
treatment of fruit juices.
I
Canning and jam-making
Long-term preservation of foods is achieved by canning. The food is first cleaned,
sorted and graded for quality. It is then blanched, which softens it and makes it
easier to pack into the cans (some foods may be cooked). The food is packed into
cans and then liquid is added. If vegetables are being canned, the liquid is usually
brine; but fruit juice or sugar syrup is used for fruits. Lids are placed on the cans,
they are sealed and then the cans are heated to a high temperature in steam under
pressure to sterilise the contents. The length of the heating period depends on the
type of food being canned, the size of the container and the pH of the contents.
Sugary foods and those with a low pH need less time than other foods. After being
held at the correct temperature for the required time, the cans are immediately
cooled in cold water. Many fruits and vegetables are preserved in this way and can
be stored for years. The texture of the food is changed: it is softer.
Heat is also used in jam-making, in which fruits are cleaned, sorted and boiled in
syrup made of water and sugar. Heating destroys micro-organisms and the syrup
removes water from the fruit. The jam is poured into jars, whilst still hot, and
sealed to prevent entry of micro-organisms. Fruit preserved in this way can be kept
for months.
Refrigeration
Many vegetable crops are grown to provide fresh produce. The crops are harvested
when they reach maturity or when they ripen, packed carefully and transported to
wholesalers, retailers, stores and markets to be sold within a short time. Freshness
can be prolonged by storing produce at cool temperatures or by packaging to
prevent loss of water by evaporation.
The activity of micro-organisms is slowed at low temperatures, so storing food
in a refrigerator kept at 1°C to 4°C will keep it fresh for several days. Where
the climate is warm, it is usual to keep opened cartons of food refrigerated to
prevent the growth of bacteria. Cooked food should be covered and cooled before
refrigeration.
218
1 4 • Processing and utilise
Freezing
freezing ►
Why is it better to freeze fresh vegetables
quickly?
At what temperature should frozen produce be
stored?
The freezing process causes water in the tissues of the food to be turned to ice. The
low temperatures needed for the process reduce the activity of micro-organisms
and may destroy some. They also stop chemical reactions inside cells as the
enzymes are inactivated. The formation of ice draws out water from the tissues
and they become dehydrated.
This process can preserve many fruits and vegetables, although the texture of soft
fruits, such as strawberries, is altered. The freezing technique is used commercially
and can also be used for fresh produce in the home.
The fruit and vegetables to be frozen are cleaned, graded and vegetables are
usually blanched. In addition to destroying micro-organisms on the outside of the
produce, blanching displaces any trapped air. The colour of some vegetables, such
as peas, beans and leafy vegetables, may become brighter. Freezing is carried out
as quickly as possible, so that large ice crystals do not form and the cells of the food
are not damaged when the tissue thaws. The temperature inside the food may
need to reach -5°C or lower before ice crystals are formed. The frozen produce is
then packaged, labelled and stored at -20°C in a freezer for months. Freezing does
not destroy all micro-organisms, so most frozen food should be cooked thoroughly
soon after thawing.
Drying
drying, dehydration ► Drying or dehydration means removing all water from foods to prevent decay.
The activity of micro-organisms stops when the water level inside cells is low. The
micro-organisms are not killed and their activity is resumed when the food is rehydrated.
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) and
grapes, herbs and peppers. The fruits are spread on trays and turned occasionally
to promote rapid and even drying. If conditions are not favourable for drying food
outdoors, it can be achieved by forcing heated air over the food.
Freeze-drying
freeze-drying ► Many foods are preserved by freeze-drying, in which food
is first frozen and then ice is converted to water vapour by
I ' o od NI.giL
sublimation ► sublimation. To carry out this process, the food is frozen
r
k4(v OC"
and then placed in a vacuum. The ice crystals are converted
' Nu rites
to water vapour without becoming liquid. The vapour recondenses to ice on metal plates provided for the purpose.
The quality of freeze-dried food is good and, although the
texture may be changed, the taste is not altered.
This technique works well with fruit and vegetables. Figure 14.2 Some
The vacuum is broken by adding nitrogen gas, which is freeze-dried food.
chemically inert, and the products can then be sealed in
airtight packages and do not need to be refrigerated. Freezedried foods are convenient as they do not take up much space and only require
water for rehydration before they can be consumed. They are used in military
rations and stores for camping trips, where it would be difficult to carry fresh food.
Freeze-drying can be achieved using a domestic freezer, and using a metal mesh
rack or a cake-cooling tray. Very thin slices of apple, for example, are spread on
Describe the process of freeze-drying.
the tray and placed in the freezer. If left for a week, depending on the thickness
of the slices and the temperature of the freezer, they should be dry and can be
riuo
reconstituted by pouring boiling water on to them. If not completely dry, they will
1
Name FOUR foods which are produced by drying.
thaw out and turn black.
219
Section B: Crop Production
Fermentation
fermentation ► Fermentation in food processing involves the use of micro-organisms, such as
yeasts and bacteria, to produce alcohol or organic acids from carbohydrates.
Fermentation is involved in the production of:
• sauerkraut from cabbage
• soya sauce from soya beans
• wine from grapes and other fruits
• beer from barley.
Sauerkraut
In sauerkraut manufacture, naturally-occurring bacteria on the surface of cabbage
ferment sugars under anaerobic conditions forming lactic acid. Cabbages are
washed in clean water, shredded and mixed with salt. The material is packed into
a large container, a weight placed on the top, and the container is covered closely.
The salt draws water from the tissues, so the cabbage shreds become immersed
in brine. Bacterial activity uses up available oxygen and the conditions become
anaerobic, favouring bacteria which bring about the formation of lactic acid.
Fermentation is complete when the pH reaches 3.5.
The container is kept between 21°C and 24°C. If the temperature is lower, then
fermentation is slow and the desired pH is not achieved. Fermentation at higher
temperatures may cause the growth of other, undesirable micro-organisms that
would cause spoilage. In this fermentation process, the micro-organisms are
respiring anaerobically, using sugars in the cabbage and producing lactic acid as
their waste product.
Soya sauce
The soya bean (Glycine max) is a leguminous plant grown throughout the world. It
is high in protein, oil and vitamins. It is poisonous if eaten raw, so must be cooked
or processed first.
The production of soya sauce consists of the following stages:
• soya beans are soaked in water, boiled, drained and added to starchy material,
such as crushed wheat or flour
• the mixture is spread out on trays and a starter culture of bacteria and moulds
is added
• fermentation takes place for a week at 28°C to 30°C; the moulds release
enzymes which break down complex carbohydrates in the mixture to simple
sugars and amino acids
• brine (17-22% solution of sodium chloride) is added and the mixture is
transferred to a large container
• a second fermentation, this time anaerobic, takes place and lactic acid is
produced, lowering the pH; the temperature is kept between 25°C and 33°C
and the process can take a few months
• the mature sauce, now a dark brown liquid, is filtered off and pasteurised
before being bottled.
Variations in flavour and colour of the sauce can be made by altering the
fermentation conditions or micro-organisms present in the starter culture. The
first fermentation is aerobic and releases sugars and amino acids used in the second
fermentation, which is anaerobic.
Wine-making
In wine-making, yeasts (Saccharomyces cerevisiae and other species) ferment sugars
under anaerobic conditions to produce alcohol. In this type of fermentation, sugars
in the fruit (mainly glucose and fructose) are respired anaerobically by yeast to
produce carbon dioxide and alcohol. Wine is usually made from grapes, but other
fruits, vegetables and grains may be used.
220
14 • Processing and utilisation
The process involves the following stages:
• the fruit is crushed and juice pressed out; skins and pips are removed if white
wine is being made; red wine is made from black grapes and some skins are
left in the juice to give colour to the wine
• the juice may be pasteurised to destroy micro-organisms on the outside of
fruit: many fruits have natural yeasts on their skins which may not produce
the desired fermentation
• the juice is placed in a large container and yeast added; initially the conditions
are aerobic because there is oxygen dissolved in the juice and the contents of
the container are mixed to encourage the growth of the yeast
• after a few days, all dissolved oxygen is used up; the mixing is stopped, the
container covered and as conditions become anaerobic, ethanol is produced
and carbon dioxide is given off
• after the first stage of fermentation, clear wine is drawn off from the residue
(a process called racking) and left to continue fermenting; this process may be
repeated several times until fermentation is complete
• the wine may be left in oak barrels to mature or bottled straightaway; red
wine is usually left to mature and develop its flavour before being drunk.
If wine is made on a smaller scale, glass fermenting bottles fitted with air locks
are used. It is then easy to follow the process of fermentation and know when
the wine requires racking. The temperature at which fermentation takes place
should be between 10°C and 20°C for white wines, but 24°C to 27°C for red wines.
Different yeasts produce different concentrations of alcohol in the wine, as well as
characteristic flavours.
Figure 14.3 Tanks used in the beer
fermentation process.
Making beer
In the brewing of beer, barley is allowed to germinate so that starch in the grains is
converted to sugars. The germination is suddenly stopped by drying and roasting
the grains, which are then ground up and mashed with water. The sweet liquor
extracted from the mash contains sugars. Yeast is added and anaerobic fermentation
produces alcohol and carbon dioxide. Hops (the flower clusters of Humulus lupulus)
are added to give the characteristic flavour and to counter the sweetness of the
remaining sugars.
Cocoa
Cocoa undergoes a fermentation process during its production (see Figure 14.4).
Cocoa pods are harvested from the trees and opened with a hammer or a machete.
The husk and inner membrane of each pod is discarded. The pulp and seeds are
removed, piled in heaps, covered with banana leaves or jute bags and allowed to
'sweat'. This is a fermentation process. During sweating, the thick pulp ferments and
becomes liquid. This takes 3-9 days and removes the bitter taste of the cocoa. During
fermentation, sugars in the beans are converted to acids (lactic and acetic acid)
and a high temperature
is generated (about
52°C). Enzymes inside
the beans are activated
and form compounds
which produce the
chocolate flavour when
the beans are roasted.
After fermentation, the
beans are dried before
being processed locally
or exported.
Figure 14.4 Cocoa beans undergoing a fermentation
process and covered with banana leaves.
221
Section B: Crop Production
Examination-style
questions
Multiple Choice Questions
1. In which food processing techniques are all micro-organisms destroyed?
A refrigeration
B freezing
C pasteurisation
D canning
2. What is the correct temperature and time for the process of
pasteurisation?
A 72°C for 3 seconds
B 72°C for 15 seconds
C 132°C for 3 seconds
D 132°C for 15 seconds
3. A pH of 3.5 is reached at the end of fermentation in the production of:
A wine
B beer
C sauerkraut
D soya sauce
4. Vegetables are blanched before canning to:
A remove minerals
B destroy vitamins
C inactivate enzymes
D alter their taste
Short answer and essay-type questions
5. (a) Outline the reasons for preserving crops.
(b) Describe the use of heat in food processing.
6. (a) How can fermentation techniques preserve food?
(b) Describe one fermentation technique that can be used to preserve
fruits.
7. (a) List the ways in which fresh vegetables can be preserved.
(b) A farmer produced a large crop of tomatoes. Apart from selling the
tomatoes locally, describe THREE ways in which the surplus crop
could be preserved.
8. Write an account of the use of processed non-food items. Include
references to the crops from which the items came and any relevant
details of the processes involved in the production of the items.
224
..........
U p and p
By the end of
this chapter
you should be
able to:
3
3
3
SIO
describe the structure and functions of the digestive system of a bird
identify the parts of the bird's digestive system
describe the digestive systems of a ruminant and a non-ruminant
animal
3
explain the functions of the parts of the digestive systems of these
animals
3
3
compare digestion in a ruminant with digestion in a non-ruminant
identify the parts of a rabbit's digestive system and explain their
functions
describe how digestion in a pseudo-ruminant, such as a rabbit, differs
from that of a ruminant
■,/
3
describe the structure of an egg and the functions of its parts.
Concept map
Animal morphology and physiology
Process of
digestion
Digestive
systems
Bird
-structure
-functions
Digestion in
rabbits
Eggs
Ingestion
Functions of
parts
Structure
Digestion
external
Ruminant
Absorption
parts
functions
Non-ruminant
internal
Egestion
parts
E functions
225
Section C Animal Production
15.1 The digestive system of a bird
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.
Stages of digestion
digestive systems ► 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.
All types of digestive systems carry out similar functions, which are:
ingestion ► • ingestion: intake of food
digestion ► • digestion: break down of food
absorption ► • absorption: uptake of nutrients into the bloodstream
egestion ►
• egestion: elimination of undigested residues (faeces).
Processes involved in digestion
physical processes ►
chemical processes ►
microbial processes ►
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.
The breakdown of food in digestion can involve physical, chemical and microbial
processes:
• Physical processes: mastication (chewing) by the teeth and muscular
contractions of the digestive tract (peristalsis) break up the food and move it
through the alimentary canal
• Chemical processes: enzymes in the digestive juices secreted along the
alimentary canal and by its associated organs bring about the break down
of food; complex food molecules are broken down into simpler, soluble
substances.
• Microbial processes: enzymes secreted by micro-organisms (bacteria and
protozoa) in the stomachs of ruminants break down cellulose; microorganisms in the colon and caecum of non-ruminants secrete enzymes that
break down limited amounts of cellulose.
Parts of the alimentary canal
What are the functions of a digestive system?
it
-
Name the main parts of the alimentary canal.
IK
What are the chemical processes involved with
digestion?
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) or complex (ruminant, e.g. sheep);
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, organs: salivary glands, liver and pancreas.
Poultry
In poultry (see Figure 15.1), the crop and proventriculus form part of the
oesophagus. The gizzard is a tough, muscular organ which contains grit, or small'
stones. Powerful muscles in the gizzard contract and relax, helping to grind food.
226
15 • Morphology and physiology
There is no grinding of food in the mouth as there are no teeth. The digestive juices
and their enzymes are similar in nature and function to those secreted by a pig.
gall bladder
1
beak
proventriculus
gizzard
oesophagus
crop
large intestine (colon)
liver
cloaca
rectum
small intestine (ileum)
caeca
Figure 15.1 The digestive system of a bird (chicken).
Structure
Functions
Beak
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.
Mouth
Oesophagus
(gullet)
Crop
Explain the functions of the beak, the crop and
the gizzard of a bird.
What is the name of the part of the digestive
system of a bird from which the faeces are
Proventriculus
Gizzard
Liver
Ileum
egested?
Caecum
Practical activity:
Examine the digestive tract of a
bird and identify the parts.
Rectum
Cloaca
Moistens food with the 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 which
help to grind food.
Produces bile which is involved with the digestion of fats.
Produces some digestive enzymes; absorbs the products of
digestion.
Usually two caeca; some digestion 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 15.1 Functions of the parts of the digestive system of a bird.
227
Section C Animal Production
15.2 Ruminant and non-ruminant digestive
systems
Ruminants
ruminants ►
Ruminants are animals (sheep, goats and cattle) that eat grass and other vegetation,
and chew the cud (ruminate). The cud is undigested
rectum
reticulum omasum small
rumen
caecum
vegetation which has been swallowed and then
(faeces stored)
(2)
(3)
intestine
(1)
regurgitated back into the mouth for thorough
chewing. When it is re-swallowed, the cud passes
anus
into the digestive system.
(faeces
The stomach in ruminants is complex. At the base
removed)
mouth
of the oesophagus there are four compartments.
(food taken in
Three of these, the rumen, reticulum and omasum,
oesophagus
(passage
i
are referred to as forestomachs; and the fourth,
to rumen)
the abomasum, is the true stomach. In the rumen,
(food is chewed, swallowed
large
bacteria and protozoa digest the cellulose in fibrous
and regurgitated to be
abomasum
intestine
ood. Ruminants crop the vegetation, which is
chewed again)
truee stomach
roughly chewed, mixed with saliva and swallowed.
It passes down the oesophagus into the rumen
Bacteria and other micro-organisms in (1) and (2) break down cellulose,
where it is stored. When the animal has finished
Water is absorbed from (3). Digestion continues in the true stomach and small intestine.
feeding, small quantities of food (each called a bolus)
are regurgitated for further chewing.
cow
(a
ruminant),
The
digestive
system
of
the
Figure 15.2
Non-ruminants
non-ruminants ►
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, but some occurs in the large intestine and caecum
due to 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.
large intestine
(absorption of water)
rectum
(faeces stored)
oesophagus
(passage to
stomach)
'
anus
(faeces removed)
Describe the process of chewing the cud.
Name the FOUR compartments at the base of the
oesophagus of a ruminant.
1
P
Practical activity:
If possible, visit an abattoir or
watch a video showing the
different parts of the digestive
systems of farm animals.
mouth
(food taken in)
!
stomach
(food stored,
proteins digested)
Figure 15.3
small intestine
(digestion and
absorption)
The digestive system of the pig (a non-ruminant).
15.3 Functions of the digestive system parts
The ruminant digestive system differs from the non-ruminant system in the
complexity of the forestomachs and the stomach. Tables 15.2 and 15.3 summarise
the digestive systems of a pig and a cow.
228
15 • Morphology and physiology
Structure
Functions
Mouth
Oesophagus
Stomach
Ingestion and mastication of food.
Transport of food from mouth to stomach.
Storage of ingested food; digestion of food begins; protein
digestion.
Bile and pancreatic juice added to food; breakdown of
carbohydrates, fats and proteins.
Further breakdown of carbohydrates, fats and proteins; absorption
of nutrients.
Duodenum
Ileum
Caecum
Colon
Rectum
Anus
Microbial digestion of some cellulose in fibrous food.
Microbial digestion of some cellulose; absorption of water.
Storage of undigested remains (faeces); absorption of water from
the faeces.
Egestion of the faeces.
Table 15.2 Functions of the parts of the digestive system of the pig (non-
ruminant).
Structure
Mouth
Oesophagus
Functions
Ingestion and mastication of food; chewing the cud.
Rumen
Storage of ingested food; addition of saliva to food; digestion of
cellulose by enzymes secreted by bacteria and protozoa.
Separation of larger pieces of food for regurgitation to the mouth
via the oesophagus.
Storage of liquefied food; muscular contractions grind food into
finer particles; water and finer food particles moved into the
abomasum.
Storage of liquefied food; chemical digestion of food by enzymes
(proteins).
Bile and pancreatic juice added; similar to the pig.
Similar to the pig.
Absorption of water from the undigested material; transport of this
material to the rectum.
Storage of undigested material (faeces).
Egestion of the faeces.
Reticulum
What is the function of the duodenum?
Omasum
Name the TWO functions of the ileum in both the I
ruminant and the non-ruminant digestive system. I
Abomasum
Practical activity:
Duodenum
Ileum
Colon
Examine preserved parts of the
digestive systems of ruminants
and non-ruminants.
Rectum
Anus
Transport of food from the mouth to the rumen; brings
regurgitated food (boluses) from the rumen back into the mouth
for rumination.
Table 15.3 Functions of the parts of the digestive system of the cow (ruminant).
15.4 The process of digestion
Digestion in the pig (non-ruminant)
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.
The stomach
oesophagus ► 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 ► peristalsis. Once in the stomach, it 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
the break down of proteins to amino acids.
229
Section C Animal Production
The small intestine
The food, now called chyme, enters the first part of the small intestine (the
duodenum ► duodenum), where 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, making 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 7-8)
for the action of enzymes in the small intestine.
Pancreatic juice contains the following enzymes:
• pancreatic amylase which continues the breakdown of starch to sugars
• lipase which brings about the breakdown of fats to fatty acids and glycerol
• trypsin which continues the breakdown of proteins to amino acids.
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 to simple sugars, the proteins to
amino acids, and the fats to 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 assimilation into the body cells.
The large intestine
After absorption has taken place, the food residues (water, undigested material,
colon ► cellulose, digestive secretions and bacteria) move into the colon, or large intestine.
Bacterial action in the caecum and the colon results in the synthesis of some
vitamins (vitamin B) and some digestion of cellulose.
rectum ► Much water is reabsorbed into the blood from the colon and the rectum,
minimising 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
Name the enzymes present in the pancreatic
juice and describe their functions,
Where does water absorption take place and why
is it i mportant to the animals?
OCIV,
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 rhythmic contractions of its walls.
Through anti-peristaltic action, larger pieces of food form boluses. These are
regurgitated in succession back up the oesophagus into the mouth. Here, each
bolus is chewed 40-50 times before being swallowed again. The chewing breaks
up the food physically and provides a larger surface area for the action of enzymes
from 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 is secreted and the
course of digestion from this point on is similar to that in non-ruminants.
In suckling ruminants, such as calves, kids and lambs, the rumen and reticulum
are not fully developed and only enlarge as young animals begin to consume solid
food. The milk they take in is channelled directly to the omasum and abomasum
for digestion.
15 • Morphology and physiology
15.5 Digestion in rabbits
pseudo-ruminant ►
caecum ►
appendix ►
coprophagy ►
The rabbit is a herbivore with a simple stomach and not a ruminant. The rabbit is
a pseudo-ruminant: it does not chew the cud or have a rumen, but it does depend
on 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 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.
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 food reaches
the caecum. Undigested food passes from the small intestine into the caecum and
appendix where there are cellulose-digesting bacteria, which break down cellulose
to organic adds. 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 re-ingested
material.
caecum containing bacteria to digest cellulose
stomach
ileum
colon
Why is fresh herbage allowed to wilt before it is
fed to a rabbit?
Explain what is meant by coprophagy.
How does coprophagy benefit the rabbit?
1
oesophagus
1
•
••
Practical activity:
duodenum
night faeces
.0.00000/
rectum
anus
• ••
• ea • •
•
second faeces (solid droppings)
Examine a dissected rabbit and
identify the different parts of the
1. Food is eaten for the first time
2. Night faeces are eaten
digestive system.
Figure 15.4 The digestive system of a rabbit (a pseudo-ruminant).
15.6 The structure of an egg
An egg contains the female gamete, or ovum, of a bird. A hen's egg is ovoid
in shape, 5 cm to 6 cm in length, with one end more pointed than the other.
The outer, protective shell is made of calcium carbonate (98%) together with
231
Section C Animal Production
vitelline membrane shell shell membranes
some magnesium and phosphate. It is hard and may vary from white to brown,
depending on the breed and age of the hen. It 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 which will develop into embryo (germinal disc)
Figure 15.5 The internal structure of
a hen's egg.
i
List the functions of the albumen.
Describe the function of the chalazae.
The egg has:
• two shell membranes which protect the inner parts; the shell is built on the
outer shell membrane; the inner shell membrane surrounds the albumen
• albumen (egg white): made up of proteins, minerals, some carbohydrate and
water; provides some food and a source of water; protects against bacterial
infection; protects the yolk from mechanical injury; albumen is of two types,
thick and thin; the thin albumen is found just below the shell and surrounding
the yolk
• chalazae: coils of twisted fibres made from albumen; hold the yolk in place
• the yolk: contains fats (phospholipids); provides food for the developing
embryo if egg is fertilised: yellow colour is due to pigments
• a germinal disc, or blastoderm; seen as 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
• the air space: this is situated at the blunt end; it is important for gas exchange;
the air space gets bigger the longer the egg is stored as water is lost from the
albumen.
To some extent, the colour of the yolk is influenced by the diet of the hen. Grass
and maize contain yellow pigments; if these are included in the poultry feed, the
yolks have a dark yellow colour.
What nutrients are found in an egg?
Practical activity:
Make labelled drawings to show
the internal and external structure
of a hen's egg. Write about the
functions of the labelled parts
beside the labels.
s-!
232
• Nutrition provides energy for growth, reproduction and the repair and
maintenance of tissues.
• Digestive systems carry out these processes: ingestion, digestion, absorption
and egestion.
• Digestion is the process in which ingested food is broken down to simpler,
soluble substances which can be absorbed.
• Digestion can involve physical processes which break up the food and move it
along the alimentary canal.
• Chemical digestion is brought about by the action of enzymes.
• Microbial breakdown of cellulose occurs in the digestive systems of some
animals. The products of such breakdown can be absorbed.
• The main parts of the digestive system are the mouth, oesophagus, stomach,
duodenum, ileum, colon, rectum and anus.
• The digestive system of a bird consists of a beak, mouth, crop, proventriculus,
gizzard, duodenum, ileum, caecum, colon, rectum and cloaca.
• Mechanical digestion in a bird is achieved by the beak and small stones in the
gizzard. A bird has no teeth.
• Ruminants are animals such as sheep, goats and cattle that eat vegetation and
chew the cud. There are cellulose-digesting bacteria and protozoa in the rumen.
• Ruminants have four compartments at the base of the oesophagus. These are
the rumen, reticulum, omasum and abomasum. The abomasum is the true
stomach.
The rest of the alimentary canal is similar in structure and function to that of a
• non-ruminant.
• In non-ruminants there is little digestion of cellulose: there may be some
cellulose-digesting bacteria in the caecum and colon and the products of such
digestion may be absorbed.
15 • Morphology and physiology
•
•
•
•
•
•
Apart from differences in the stomachs, digestive processes are similar in both
ruminants and non-ruminants.
The rabbit is a herbivore with a simple stomach. It has cellulose-digesting
bacteria in its caecum.
The rabbit produces two types of faecal pellets: soft pellets at night which are
ingested and hard, dry pellets during the day. The ingestion of the soft pellets is
called coprophagy.
The rabbit is a pseudo-ruminant. It benefits from the bacterial breakdown of
cellulose but it does not chew the cud.
The main structures in a hen's egg are the shell, albumen and yolk.
The shell is a hard, protective structure; the albumen also protects the yolk and
holds it in place.
ITQl
The functions of a digestive system are ingestion, digestion, absorption
and egestion.
ITQ2 The mouth, oesophagus, stomach, duodenum, ileum, colon, rectum and
the anus. Also, the associated organs of the salivary glands, the liver and
pancreas.
ITQ3 Enzymes in digestive juices break down complex food compounds into
simpler, soluble substances.
ITQ4 The beak takes food into the mouth and breaks up food before
ingestion; the crop stores food and moistens it with digestive juice; the
gizzard is the muscular part of the stomach and contains small stones
which grind the food.
11115
The cloaca.
ITQ6 Food is cropped and roughly chewed before being swallowed and passed
into the rumen for temporary storage. Small portions of food, called
boluses, are regurgitated back into the mouth and chewed 40-50 times
before being swallowed again.
ITQ7 The rumen, reticulum, omasum and abomasum.
ITQ8 The function of the duodenum is to continue the digestion of the food. It
receives bile from the liver and pancreatic juice which contains enzymes
that break down carbohydrates, fats and proteins.
11. 09 The two functions of the ileum are digestion and absorption. The final
digestion of carbohydrates, fats and proteins occurs here by means
of enzymes contained in the intestinal juice. The soluble products of
digestion are absorbed in this region.
IT010 The enzymes in pancreatic juice are pancreatic amylase which digests
starch to sugars, lipase which breaks down fats to fatty acids and glycerol,
and trypsin which continues the breakdown of proteins to amino acids.
IT(111 Water absorption takes place in the colon and the rectum. It is important
to minimise water loss from the body.
1 -11112 To reduce the water content and to prevent the formation of soft, watery
faeces.
11113 Coprophagy means to eat dung and refers to rabbits eating the soft faecal
pellets produced at night.
111114 The benefit to the rabbit is that they are able to ingest the products of
cellulose digestion resulting from bacteria in the caecum.
IT1315 The albumen provides food, provides water, protects against bacterial
infection and protects the yolk from mechanical injury.
IT016 The chalazae hold the yolk in place inside the shell.
11017 In an egg, there are carbohydrates, proteins and minerals in the albumen,
together with lipids in the yolk.
233
A
Section C Animal Production
Examination-style
questions
Multiple Choice Questions
1. Digestion is :
A the intake of food
B the break down of food
C the absorption of food
D the elimination of faeces
2. The muscular part of the stomach of a bird is called:
A the oesophagus
B the crop
C the proventriculus
D the gizzard
3. The true stomach of a ruminant is called:
A the abomasum
B the omasum
C the reticulum
D the rumen
4. 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
5. The vitelline membrane in an egg:
A provides a base on which the shell is formed
B surrounds and supports the yolk
C surrounds the albumen and the yolk
D forms twisted fibres to hold the yolk in place
Short answer and essay-type questions
5. (a) What is the meaning of digestion?
(b) Describe THREE major activities by which food is digested or broken
down.
(c) Of what importance is digestion to farm animals?
6. (a) Define what is meant by a 'digestive system'.
(b) State the functions carried out by digestive systems.
(c) List the main parts of the digestive system.
(d) Explain why a limited amount of cellulose digestion takes place in
the digestive tract of non-ruminants.
7. (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 the fowl's
digestive system:
Parts
proventriculus
crop
Functions
caecum
(b) Describe the process of food digestion in the gizzard of the fowl.
9. (a) Explain the meaning of 'cud' as it relates to ruminants.
(b) State the functions of the various parts of the ruminant's stomach.
(c) Describe the process of food digestion in the stomach of an adult
ruminant.
234
nn
..............
dtiltiOn
By the end of
this chapter
you should be
able to:
3
3
3
3
3
3
3
3
3
3
3
name and state the roles of the constituents of animal feeds and feed
rations
carry out simple food tests to identify carbohydrates, proteins and fats
state the use of materials from food processing in animal feedstuffs
describe the essential constituents of a balanced ration
choose appropriate rations for different stages of growth in poultry
calculate the Feed Conversion Ratio (FCR) and explain its importance
describe pasture management and systems of grazing
assess the advantages and disadvantages of different grazing
systems
describe the different legumes and grasses that make up forage
explain the importance of forage in livestock feeding
explain the value of supplementary feeding when fresh forage is
unavailable.
Concept mai
iD
Nutrition
Nutrients
Balanced
rations
Components
of diet
Components
carbohydrates
For layers
and broilers
proteins
starter ration
minerals
finisher ration
vitamins
laying ration
Feed Conversion
Ratio
Grazing
systems
I mportance
Rotational
Calculation
Zero grazing
Forages
Types
-grasses
-legumes
-non-legumes
Continuous
grazing
Forage
conservation
Strip grazing
[hay making
silage making
Deferred
grazing
roles
sources
grower ration
Pasture
management
235
Section C Animal Production
16.1 Nutrients in animal nutrition
nutrients ► Nutrients are the substances in food that animals need in order to stay healthy.
They are essential for the growth, energy, body maintenance and reproduction of
farm animals.
Farm animals get their nutrients from the following sources:
• plants: grasses, forage crops, legumes
• plant products: corn, soyabean, oat bran, rice husks
• animal products: bone meal, milk, fish meal.
The groups of nutrients required by farm animals are carbohydrates, fats, proteins,
vitamins, minerals and water.
Carbohydrates
carbohydrates ►
F
monosaccharides ►
disaccharides ►
I,
iE
ikt
polysaccharides ►
Carbohydrates are energy-producing foods and contain carbon, hydrogen and
oxygen, e.g. C 6 H 12 0 6 (glucose).
Carbohydrates can be of three types:
• monosaccharides: simple sugars, e.g. glucose, fructose
• disaccharides: consist of two monosaccharide units, e.g. maltose, sucrose,
lactose
• polysaccharides: composed of many monosaccharide units, e.g. starch,
cellulose.
Carbohydrates in the diet of farm animals provide energy for:
• metabolic activity
• physical work
• the production of meat, milk and eggs.
Sources of carbohydrates are plants, such as pasture grasses, and plant products
such as root crops, fruits, seeds and grains.
Figure 16.1 Sweet potatoes are a
carbohydrate food.
Proteins
proteins ► Proteins are organic compounds made up of amino acids. They are essential for the
formation of all living cells. They contain carbon, hydrogen, oxygen and nitrogen,
together with sulphur and phosphorus.
Proteins in the diets of farm animals are essential for:
• building new cells and tissues, including muscles
• producing milk, eggs, wool, hair and feathers
• body maintenance: the repair and replacement of tissues
• producing enzymes and hormones.
Sources of proteins include plants, such as pasture legumes, cowpea and soyabean,
and animal products, such as fish meal, bone meal and blood meal.
Fats (lipids)
fats ► Fats are made up of fatty acids and glycerol. They contain carbon, hydrogen and
oxygen, and are similar to carbohydrates in that they are energy-producing foods.
Fats contain more energy per unit weight than any other food constituent; about
2.5 times that of a similar weight of carbohydrate.
Fats in the diet of farm animals are used to:
• supply energy
• store energy.
In farm animals, surplus energy from carbohydrates is converted to fat. This is
stored under the skin, within the muscle tissues and in the abdominal cavity.
236
1 6 • Nutrition
Sources of fats include coconut meal and linseed meal after the oil has been
extracted. The lipid content of forage rarely exceeds 4% but it is rich in unsaturated
fatty adds.
Vitamins
vitamins ►
Vitamins are organic compounds required in the diet in small quantities for healthy
growth and development. They are grouped into:
• fat-soluble vitamins: vitamins A, D, E and K
• water-soluble vitamins: vitamins B and C.
Their major role in the diet is to promote normal health, growth and development.
A lack of vitamins may result in diseases or abnormalities, such as:
• retarded growth
• poor reproduction
• skin ailments
• haemorrhage (over-bleeding)
• diarrhoea
• night blindness
• rough coat
• muscular problems.
Sources of vitamins include green pasture grasses, cereal grains and sunshine
(vitamin D is manufactured in the body in the presence of sunshine).
Minerals
minerals ►
From which sources do farm animals derive their
food?
Name the THREE types of carbohydrates.
!TIN
List the elements present in proteins.
Explain why vitamins and minerals are essential
in the diet of farm animals.
Practical activity:
Carry out simple food tests to
identify carbohydrates, proteins
and fats:
Carbohydrates: Benedict's tests
for simple sugars; iodine test for
starch
Proteins: Biuret test
Fats: Grease spot test; emulsion
test.
1
Minerals are essential in the diet of farm animals as they have a similar role to
vitamins in promoting healthy growth and development (see Table 16.1). There
are 16 essential mineral elements which can be divided into two main groups:
• major or macro-elements needed in fairly large amounts: calcium,
phosphorus, potassium, sodium, chlorine, sulphur and magnesium
• micro or trace elements needed in very small amounts: iron, zinc, iodine,
copper, manganese, cobalt, selenium, fluorine and molybdenum.
Mineral elements
Specific roles in the body of farm animals
Calcium and phosphorus
•
•
•
•
•
1
Sodium, chlorine,
potassium and
magnesium
Sulphur, manganese, zinc
and molybdenum
Iodine
Iron
Cobalt
for strong bones and teeth
for tougher egg-shells in poultry
to prevent milk fever in dairy cattle (cows)
to maintain the acid-base balance
for osmotic control of water distribution
• for manufacturing proteins
• for manufacturing enzymes
• to manufacture the hormone thyroxine, and for
preventing goitre
• to promote the development of haemoglobin
• to prevent anaemia
• for making vitamin B12
Table 16.1 Minerals and their role in animal nutrition.
Farm animals derive minerals from:
• green pasture grasses and forages
• legumes, including pasture legumes
• cereal grains, such as corn and rice
• mineral licks (salt-licks/blocks)
• blood meal, fish meal, bone meal.
237
Section C Animal Production
Local materials for livestock feeds
Feed for farm animals can be de ri ved locally. Several crop plants (cereals, grasses
and legumes) are specifically grown for animal feed. Crops that do not reach
marketable quality (sweet potato, yam, carrot and cassava, for example) and the
t ri mmings from leafy crops such as cabbages are also used to feed livestock.
By-products from the processing of food are good sources of animal feedstuffs.
These include:
• bagasse and molasses from the processing of sugar cane: used for cattle feed
• fish meal from fish: a high protein supplement used in aquaculture
• ri ce bran, rice husk and rice-middling: used for rabbits and horses in the form
of a bran mash
• wheat-middling, wheat bran, oat bran, soya bean meal from the milling and
processing of cereals: used for rabbits and horses; soya bean meal is used as a
protein supplement for dairy cows
• citrus pulp and citrus meal: provide a concentrated source of nutrients for
dairy and beef cattle and sheep; rich in calcium
• coconut meal: protein supplement for livestock
• cocoa pod meal from the processing of cocoa beans: used in livestock and
poultry feed
• brewer's grain and hops from the brewing industry: good source of proteins
and water-soluble vitamins; useful for both ruminants and non- ru minants
• urea from fe rtiliser manufacture: urea/bagasse mix is used to feed beef cattle
• waste food (swill) from restaurants and hotels: used to feed pigs,
Practical activity:
Examine samples of different
feedstuffs and evaluate their
nutritional benefits to farm
livestock,
U, i
16.2 The balanced ration
ration ►
4
What is the difference between a maintenance
ration and a production ration?
r,
State why it is important not to oversupply any of
the food constituents of an animal's diet.
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 two parts:
• the maintenance requirement: for body repairs and metabolic processes
• the production requirement: for the production of meat, milk or eggs.
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.
41rl
u►, ,
Types of rations
grt•r
There are three types of rations: maintenance, production and balanced. The
maintenance ration ► maintenance ration is a diet which satisfies the energy (carbohydrates and fats)
and protein needs of the animal. It provides for 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. Meat, milk, eggs, hair,
wool and offspring (calves, lambs, kids) result from the production ration.
The balanced ration consists of all the essential nutrients in amounts needed to
balanced ration ►
satisfy both maintenance and production requirements of the animal.
X11
Ali
^►f
WI
M►'
b..
238
16 • Nutrition
Practical activities:
1. Examine labels from
commercial rations and identify
A balanced ration:
• supplies all the essential food constituents
• has the correct proportion of energy to protein, as well as vitamins and
minerals
• is usually more palatable and satisfies the animal's appetite.
the components.
A lack of any essential food constituent may damage the health and production
of the animal. But overfeeding can also be a problem. Feeding too much food
will waste the farmer's money. Nutrients will just be lost in the faeces and health
problems may develop in the farm animal.
2. Visit a local feed mill.
ca•
Name FOUR different types of feedstuffs.
16.3 Appropriate rations for livestock
Feedstuffs
feedstuffs ►
forages ►
fodder ►
silage ►
concentrates ►
Suggest why high protein feed is fed to chicks
until they are 6 weeks old.
Practical activities:
1. If possible, raise 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.
starter ration ►
grower ration ►
laying ration ►
finisher ration ►
Livestock feeds, known as feedstuffs, provide nutrients for energy, growth and
development, maintenance, production and reproduction.
Feedstuffs can be classified into the following groups:
• forages: green pasture grasses, legumes, mulberry and neem; the farm animals
are allowed to graze or the forages are cut and fed to them in stalls; also
includes the thick, fleshy, juicy stems, roots, fruits and leaves of certain crops,
such as sweet potato, cassava and banana
• fodder: dried feedstuffs, such as hay, straw and chaff, are used when forage
is unavailable; can also include green chopped feedstuffs, such as corn stalks,
elephant grass and kudzu
• silage: pasture grasses, legumes and other crops conserved and stored in silos
• concentrates: commercially produced in feed mills using local and imported
foodstuffs; designed to suit the maintenance and production needs of different
farm animals; they can be mixed, mashed, ground, granular or pelleted; they
may be high protein, low protein, high fibre, low fibre, high carbohydrate,
rich in essential vitamins and minerals, low percentage fat or low moisture
content.
The nutritive value of feedstuffs varies. Laboratory analysis provides information
on the total amounts, in percentages, of 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 which have been digested. This means that some nutrients are always lost in
the undigested material which passes out in the faeces.
Broilers and layers
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, layer or egg ration
• the cost: high protein feeds (e.g. starter) are
usually more expensive than low protein
feeds, such as finisher.
Figure 16.2 Layers need a
certain type of ration.
Poultry are fed starter ration from day-old chicks until they are 6 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 reared for production (broilers) are fed on finisher ration from 7 to 9
weeks old.
239
Section C Animal Production
16.4 Feed conversion ratio (FCR)
All farm animals, especially those reared for meat (broilers, piglets and calves),
feed conversion ratio (FCR) ► convert feed consumed into body mass. The feed conversion ratio (FCR) is the
number of units of feed (kg) which the animal requires to produce a one unit (kg)
increase in its body weight. 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 needed to produce a 1 kg increase in body weight.
This ratio is associated with efficiency on the part of the farm animal and
economics in terms of the cost of feed to the farmer. However, 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 converters than those with the higher
FCR.
A young animal converts feed more efficiently than an older one. 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 16.2.
Live weight (kg)
15
45
60
Feed Conversion Ratio (FCR)
1.5 : 1
2.5 : 1
3.0 : 1
90
3.5 : 1
Table 16.2 Variation of FCR with size in a pig.
Different classes of livestock have different FCRs, as shown in Table 16.3.
Class of livestock
cattle
pig
goat
rabbit
chicken
Feed Conversion Ratio (FCR): average
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 16.3 FCR of different classes of livestock.
Calculating FCR
Question: How much feed would need to be supplied to a group of 12 pigs, average weight
60 kg, in order for them to increase their average weight to 70 kg?
Define Feed Conversion Ratio.
ti
Suggest why a young animal has a more efficient
FCR than an older one.
Answer:
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 X 30) = 360 kg.
16.5 The importance of FCR
Feed is a major expense in rearing livestock, especially meat-producing animals.
Farmers are well aware of this fact!
An understanding of FCR can be helpful in:
• selection of classes and breeds of animals which have a low feed conversion
ratio
• identification of particular animals which are efficient feed converters: these
can be kept for replacement stock and breeding purposes
• raising early-maturing farm animals, thereby controlling expenditure on feed
240
16 • Nutrition
List TWO benefits of understanding feed
conversion ratios to the farmer.
• marketing batches of mature farm animals promptly before the feed
conversion ratio increases: this avoids spending more on feed at a time when
the increase in body weight is slowing down.
16.6 Systems of grazing
is
Grazing animals eat grasses or the leaves
of other plants. Examples of grazing
animals are cattle, goats and sheep.
Grazing systems (see Figure 16.3) 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.
d
a
Le
e,
R
rotational
grazing
continuo
grazing
zero
grazing
Figure 16.3 The main types of
grazing systems.
Zero grazing (soilage or soiling)
Lew grazing ►
Figure 16.4 Livestock being fed in a
zero grazing system.
rotational grazing ►
Int
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/legume mixtures used in this system include:
• elephant grass/Centrosema
• guinea grass/kudzu
• Guatemala grassl Stylosanthes
• pangola grass/Centrosema.
Rotational grazing
In rotational grazing, the pasture area is sub-divided into six or eight paddocks.
Each is systematically grazed in sequence, the ruminants being moved from one
paddock to another. The stocking rate is usually high, (20 to 25 cows per hectare).
Each paddock is grazed for 3 to 7 days, depending on stocking rate and herbage
growth. After that time, the paddock is rested and the animals are moved on 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
F
paddock 1
(grazed for
3-7 days)
4
1
paddock 2
I
paddock 3
paddock 4
paddock 5
paddock 6
)1s.
ruminants are moved from one paddock to another in sequence
Figure 16.5 Rotational grazing.
d
241
Section C Animal Production
Strip grazing
strip grazing ►
Strip grazing is a variation of the rotational
system: a single paddock is progressively
grazed, 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.
Continuous grazing
continuous grazing ►
forward movement
fixed fence
f
restricted area
or strip for
grazing
ruminants
electric fences
fixed fence
moved forward
In continuous grazing, animals are
once or twice daily
allowed to graze on the same pasture
area for a very long period. This system Figure 16.6 The strip grazing system.
is normally only practised on expansive
range lands where fencing is absent and probably impractical. The stocking rate is
usually low.
Figure 16.7 The continuous grazing system.
Deferred grazing
deferred grazing ► In deferred grazing, certain paddocks of pasture grass/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/kudzu and giant star
grass/Centrosema are most suitable for this type of grazing.
Pasture management
Farmers who rear ruminants recognise the importance of establishing good
pastures and managing them effectively.
A well-managed pasture will:
• provide much palatable, 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.
Management tips
On well-established pasture, the farmer can maintain the pasture by carrying out
these activities:
242
16 • Nutrition
Name THREE types of grazing systems.
(ED
Why is it important to carry out pasture
management?
Practical activity:
Visit farms with ruminant animals.
Observe their grazing systems and
how the pasture is managed.
• adopting systems of grazing to achieve the most efficient use of the forage
produced
• avoiding over-grazing or close grazing: regrowth and root development of
grasses and legumes is slowed; death of forage plants could result in bare
patches and soil erosion
• avoiding under-grazing: this leads to a decrease in the nutritive value of the
pasture (protein content decreases and the fibre content increases) and this
promotes patches of tall, dense grass
• tine-harrowing the pasture after rotational grazing and after rain: matted
stolons are broken up, dung from grazing animals is spread around, and
growth of unsuitable grasses is prevented
• mowing or brushcutting pasture after rotational grazing: coarse growth is
removed, tillering of the grasses is promoted and weeds are controlled
• applying fertilisers at regular intervals: nutrients for plant growth are supplied
and the rapid re-growth of the forage is promoted
• clearing clogged drains and water-courses
• mending pasture fences
• pruning or re-planting shade trees.
16.7 The advantages and disadvantages of
different grazing systems
Zero grazing
The advantages of zero grazing are that:
• efficient use is made 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.
The disadvantages include:
• the need for special machinery and equipment for harvesting, transporting
and chopping
• the high cost of setting up and maintaining housing for the animals, the
machinery and equipment
• increased labour costs, bedding material for the animals and manure disposal
• restriction on numbers of animals reared: it is only suitable for small herds of
ruminants.
Rotational grazing
The advantages of this system are that:
• it overcomes the problems associated with over-grazing 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.
It has the following disadvantages:
• 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.
Strip grazing
Strip grazing is most suitable for high quality pastures as animals will have a restricted
intake if pasture is poor. The advantages are similar to those for rotational grazing,
243
Section C Animal Production
except that there is less selective grazing, the pasture is grazed more uniformly and
there is less trampling and fouling with dung. This type of grazing produces a high
level of animal production. Efficiency of forage use can be increased by 15 to 20 %
on high quality pastures.
Continuous grazing
State TWO advantages and TWO disadvantages of
zero grazing.
r
Why does rotational grazing need a large area of
pasture land?
t )
Explain why the pasture area is under-grazed
during the rainy season in a continuous grazing
system.
The advantages and disadvantages of this system are dependent on the seasons. In
the rainy season, there is an abundance of forage and pasture is normally undergrazed because the stocking rate is relatively low. However, in the dry season,
overgrazing can occur and the sward takes a longer time to recover and re-grow.
During the dry season, animals may need to be supplied with an additional submaintenance ration. Another disadvantage is the build-up of ticks and intestinal
parasitic worms on the pasture.
Deferred grazing
Deferred grazing provides a maintenance ration for animals during the dry season.
This system can be used by ruminant farmers in the tropics. It has disadvantages
in that it only provides a maintenance ration and taller grasses may smother the
growth of legumes, creating an imbalance in the grass/legume sward.
16.8 The importance of forages in livestock
feeding
In selecting forage plants (grasses and legumes), farmers need to consider:
• productivity: high-yielding varieties which have rapid growth and respond
favourably to nitrogen fertilisers
• palatability: farm animals will eat more if the grasses are tasty
• nutritive value: some plants are more easily digested than others, some are
particularly high in protein or minerals
• adaptability: plants need to adapt to soil and weather conditions (high rainfall
in wet season, drought in dry season so plants must be drought-resistant).
The nutritive 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, a precursor 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) as shown in Table 16.4.
Pasture grasses
Soiling grasses
Cultivated and managed as a crop.
Farm animals are allowed to graze the
sward (grassy area or pasture).
Cultivated and managed as a crop.
Usually farm animals are not allowed
to graze.
Suitable for rotational and continuous
grazing.
Examples: pangola, para.
Normally cut and fed to farm animals
(zero grazing).
Examples: elephant, Guatemala, guinea._
Table 16.4 A comparison of herbage grasses.
Pangola grass (Digitaria decumbens)
Pangola grass is a native 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
244
16 • Nutrition
continuous close grazing, flooding and drought. It responds favourably to nitrogen
fertiliser and can be propagated by stem cuttings or root divisions (setts).
Para grass (Brachiaria mutica)
Para grass is a native of tropical Africa and of South America, including Trinidad.
It is a creeping perennial with stolons and produces stems which grow to 2 m
or more. It is very suitable for moist, lowland pastures and provides excellent,
palatable fodder when eaten young. It does not stand up well to heavy or
continuous grazing, but it grows well in combination with Centrosema.
Elephant grass (Pennisetum purpureum)
Figure 16.8 Para grass.
Elephant grass, or napier grass (sometimes
referred to as a king grass), is indigenous
to Nigeria and has spread throughout
tropical Africa. It is a tall, tufted or bunched
perennial growing 4 to 4.5 m high. It is
high-yielding and palatable, with a high
nutritive value when young and not too
fibrous. It is drought-resistant but cannot
withstand 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.
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 only grows 2 to 3 m high. It can
withstand drought but dies if heavily grazed.
It is excellent for zero grazing and combines
well with Centrosema and Stylosanthes. It can
be established by seeds or root-divisions
(setts).
Figure 16.9 Elephant grass.
Guatemala grass (Tripsacum laxum)
This perennial grass grows tall and leafy, forming large clumps. It is droughtresistant but easily uprooted by grazing animals. It is a good grass for silage-making
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 which 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 is tolerant of close grazing. It does not set viable seed and has to
be established from cuttings.
Antelope grass (Echinochloa pyramidalis)
Figure 16.10 Guatemala grass.
Antelope grass is a native of southern Africa and is a reed-like perennial growing
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 the grain is used as human food.
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, with which it hybridises. It can be
propagated from stem cuttings and is easily established to give complete ground
cover. In contrast to para grass, it can withstand heavy grazing. It has a high nitrate
content and is toxic to cattle under certain conditions.
245
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 nutritive value of the forage grass and
legume combination.
The legumes are superior to grasses in protein and mineral content. Their nutritive
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
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 below.
Stylosanthes
There are several species of Sylosanthes used as forage plants. Style Caribbean
(Stylosanthes hamata) is a short-lived perennial legume which can grow in hot dry
conditions. It will grow on well-drained soils and is tolerant of heavy grazing. It
can be planted with sown grasses, but is generally oversown into native pasture
after the pasture has been treated with fertiliser. Stylosanthes guyanensis is suited
to poor soils in high rainfall areas. It has a high nutritive value if 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 he propagated by seeds.
Centro or Centrosema (Centrosema pubescens)
Centro is a leafy perennial which trails along the ground. It can be established from
seed and may be combined with Bermuda, Guinea, elephant and para grasses.
Figure 16.11 Centrosenia.
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 leaf after shallowrooted grasses have run out of moisture.
Gliricidia (Gliricidia sepium)
Glyricidia is an evergreen shrub cultivated for green fodder. It can be interplanted
with elephant grass and is a source of protein.
Figure 16.12 Gliricidia.
246
16 • Nutrition
Non-legumes
Other herbs and shrubs, such as mulberry and neem, may be used as forage for
ruminants.
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)
Figure 16.13 Mulberry.
Name TWO pasture grasses and two soiling (zero
grazing) grasses.
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 to 1200 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
Give THREE reasons why pasture legumes are
important forage plants.
ca)
The leaves of Trichanthera (Trichanthera gigantea) can be eaten by pigs.
16.9 Forage conservation
Which legume provides the highest quality feed?
Why should farmers use forages before they have
reached the mature stage?
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.
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 Topic 16.7).
Hay making
Hay making has two requirements: young grass with an abundance of leafy
materials, together with sunny and windy conditions.
The process involves:
• cutting the grass at the desirable stage of growth
• rapid drying, using sunshine and wind, so that moisture content is reduced
from 80% to 15-20%
• stacking and storing in a cool dry area of the barn
• using it when required for feeding ruminant livestock.
Grass is cut before the flowering stage when its nutritive value, palatability and
yield are high. The cut grass is spread out in rows on the open field and turned at
regular intervals for rapid, uniform drying. When the moisture content has been
reduced, hay is collected into small bundles and stacked. Stored hay should be
unblemished, unbleached and have a pleasant aroma.
List the steps involved in hay making.
Silage making
silage ►
ensiling ►
silo ►
Silage consists of green forage crops which 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 is cut, while 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. Silos may be of the following types:
pit silo, tower silo, clamp silo or stack silo.
247
7
Section C Animal Production
ire
Explain the term silage.
Ensilage involves the following stages:
• cutting the grass or forage crop: this is done at the young, leafy immature stage
and wilted in the sun to reduce moisture content
• filling the silo: cut mate ri al is spread uniformly in layers in the silo
• compression of the mate ri al: a four-wheeled tractor or heavy roller is used;
this controls respiration within the mate ri al in the silo
• addition of molasses: 3 -4% by weight, diluted equally with water, sprayed
evenly on to the cut material to sta rt fermentation
• fermentation: aerobic bacteria conve rt carbohydrate into acetic acid and lactic
acid
• temperature control: temperature within the silo should be around 32-38°C;
inadequate compaction results in excessive respiration and overheating; it
also creates conditions favourable for bacteria to produce butyric acid (not
desirable)
• pH regulation: acidity needs to be at pH 4.2 or lower to suppress the
production of buty ri c acid which makes the silage foul-smelling and
unpalatable.
i
What happens during the fermentation stage of
silage making?
^r
Why should the acidity level of silage be pH 4.2
or lower?
Over-compaction of the silage can also create conditions in which buty ri c acid is
formed by bacteria.
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.
• Farm animals obtain nutrition from food through the process of digestion.
• The major food substances are carbohydrates, fats, proteins, minerals, vitamins
and water.
• Feedstuffs, or foods for livestock, may be grouped into forages, fodder,
concentrates and silage.
• The nutritive value of feedstuffs va ri es, but can be determined by laboratory
analysis and expressed as total digestible nutrients (TDN) or net energy values
( NEV).
• Feedstuffs can be prepared from local and imported material.
• The ration of a farm animal should be balanced, supplying all essential food
substances in their correct propo rt ions.
• A maintenance ration supplies the energy and protein needs of the animal
without any gain or loss in its weight.
• The production ration is the extra food, added to the maintenance requirement,
which is used for productive purposes.
• Appropriate rations take into account the age and stage of growth and
development of the animal.
• 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.
• The feed conversion ratio helps farmers to select suitable breeds of animals and
to control expenditure on feed.
• Grazing systems are designed to make the best use of pasture in the production
of ruminant animals.
• The main grazing systems are zero grazing, rotational grazing and continuous
grazing.
• Ruminant livestock farmers usually manage pastures on a sustained basis,
adopting techniques such as tine-harrowing, fe rt ilising, grazing and replanting.
248
16 • Nutrition
•
•
•
•
•
•
Although grass is the cheapest food for ruminants, factors such as adaptability,
productivity, palatability and nutritive value are considered in establishing a
pasture.
A grass/legume pasture is more palatable and better balanced nutritionally than
a grass pasture only.
Grasses used as herbage may be grazed (pasture grasses) or grown as a crop and
then cut and fed to animals (soiling grasses).
Pasture legumes add nitrogen to the soil, promote the growth of the pasture
grasses and increase the nutritive value and palatability of the forage.
Due to the seasonality of rainfall in the Caribbean, farmers adopt forage
conservation strategies, such as hay and silage making.
Ruminant livestock farmers cultivate and use pasture grasses, legumes and also
non-legumes, such as sugar cane and mulberry.
11111
Animals derive their food from plants (grasses, forage crops), plant
products (corn, oat bran) and animal products (bone meal, fish meal).
ITQ2
Monosaccharides, disaccharides and polysaccharides.
ITQ3
Carbon, hydrogen, oxygen, nitrogen, sulphur and phosphorus.
ITQ4 Vitamins and minerals are essential for the functioning of cells and
body processes, for healthy growth and development. A lack results in a
deficiency disease and the animal may not develop properly.
ITQ5 A maintenance ration supplies the animal's energy and protein needs
with no gain or loss in weight, but a production ration supplies the extra
food needed to produce meat, eggs, milk or wool.
ITQ6
An oversupply may cause the animal to become unhealthy and it is an
economic loss for the farmer.
ITQ7
Forage, fodder, concentrates and silage.
ITQ8 High protein feed is given to chicks as this is the stage at which they are
growing most rapidly. It is used to form new body tissues and strong
bones.
ITQ9 The feed conversion ratio is the number of units of feed (kg) required to
bring about an increase of one unit (kg) of body mass.
IT010 A young animal has a more efficient FCR because it is younger and
smaller and it converts food more efficiently.
ITI311 Any two from: selection of breeds with low FCR; identifying efficient feed
converters; raising early-maturing farm animals; controlling expenditure
on feed.
11012 Any three from: zero, rotational, continuous, strip, deferred.
IT013 To provide an abundant and continuous supply of nutritious food; to
promote forage conservation; and to reduce expenditure.
!TIN Advantages: it makes efficient use of the forage; there is a high level of
production; herbage is not fouled by dung or trampling; herbage can be
fed at its most nutritious stage. Disadvantages: needs special machinery;
costs more to set up; increased labour costs; only suitable for small herds.
IT015 A large area of land is needed to move the animals every few days and
give the pasture time to recover from grazing.
IT016 The stocking density is low and the grasses grow at their most rapid rate.
11. 017 Two pasture grasses: from pangola and para. Two soiling grasses: from
elephant, Guatemala, guinea.
J
249
Section C Animal Production
11018 Pasture legumes are important forage plants because they add palatability
and nutritive value to the forage. They add nitrogen to the soil, help to
- maintain the fertility and promote the growth of grasses.
IT019 Leucaena.
11020 It is recommended that forages are used when they are green and
succulent and before they produce flowers and seeds. At the young stage,
the nutritive value is highest.
11021 Hay making involves: cutting grass, turning grass to wilt it, collecting it
into bundles, stacking and storage.
11022 Green forage crops are cut and preserved to be in a nutritious and
palatable form. It involves compression of the herbage, addition of
molasses and fermentation to reach a pH of 4.2 or less.
11023 Bacteria convert the carbohydrate (sugars) into acetic and lactic acids.
11024 To prevent the formation of butyric acid, which makes the silage smell
and taste bad.
Examination-style
questions
Multiple Choice Questions
1. A Biuret test can be used to detect the presence of:
A carbohydrates
B lipids
C proteins
D vitamins
2. Dried feedstuffs, such as chaff, hay and straw, are known as:
A forage
B fodder
C silage
D concentrates
3. The appropriate ration for broilers would be:
A starter
B grower
C finisher
D layer
4. 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
Short answer and essay-type questions
5. (a) Explain the meaning of: (i) forage, and
(ii) forage plants.
(b) Name examples of the following forages:
(i) THREE 'indigenous' to the Caribbean
(ii) THREE 'introduced' into the Caribbean.
State
the main qualities which should be considered in selecting
(c)
forages.
6. (a) Distinguish between (i) grasses, and
(ii) legumes (pasture).
(b) List, with TWO examples each, the main groups of:
(i) grasses, and
(ii) legumes (pasture).
Name
TWO examples of each of the following:
(c)
(i) grasses introduced into the Caribbean.
(ii) legumes (pasture) introduced into the Caribbean.
250
16 •
Nutrition
7. (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
8. (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.
9. (a) List the major types of grazing systems.
(b) Describe any TWO systems you have listed for (a), using the
following sub-heads:
(i) name of grazing system
(ii) description
(iii) advantages
(iv) disadvantages.
10. (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?
12. (a) List the major forage conservation practices which Caribbean farmers
may adopt.
(b) Describe the process and procedure of hay making.
(c) State the desirable qualities of hay.
13. (a) What is silage?
(b) List the types of silos used for making and storing silage.
(c) Describe the process of silage making.
251
IH
I ^ III ^^^
uu II
IIInunoum■...■
IIIIIII
ou$
...........
I
I lI
By the end of 3 understand the principles that govern the housing requirements of
this chapter
farm animals
you should be 3 describe appropriate housing and space requirements of broilers and
able to:
layers
3 describe appropriate housing for rabbits
3 describe the establishment of a bee production system
3 explain the factors involved in setting up a fish farm.
Concept map
252
17 • Housing
17.1 Housing requirements for farm animals
N
f
North East
trade winds
Al
Figure 17.1
Orientation of a livestock
pen.
0
Why does good ventilation need to be provided in
a building for housing animals?
0
List FOUR safety features that should be included
in animal housing.
0
Why should farm buildings have rough, sloping
concrete floors?
Several factors, including cost of labour and building materials, are involved in the
design and construction of housing for farm animals. Other major factors are:
• purpose: type of farm animal, e.g. rabbits, poultry
• location (site chosen): stability of ground; well-drained and not prone to
flooding or landslides; proximity to pastures, field plots, manure heaps and
other farm buildings
• orientation to give protection from the elements (see Figure 17.1): pens are
constructed lengthwise in a north-easterly direction, protecting animals from
direct sunlight during the morning and afternoon
• ventilation: good ventilation disperses heat, foul gases (odours) and moisture;
promotes air circulation and temperature control
• lighting: natural light is needed during the day; electric lighting is necessary at
night-time; good lighting helps to keep away predators and vampire bats
• predator control and security measures: chain-link fences with padlocked
gates around pens; wire mesh in upper parts of the walls to the ceiling; flood
lighting at strategic points around the buildings from dusk to dawn; ceiling
lamps within the pen; security measures to keep away stray cats, dogs,
vampire bats, mongooses, rats and thieves
• sanitation: designed for easy cleaning with rough, concreted and sloping floor,
channel for speedy removal of effluent into a slurry pit or biogas digester, and
an appropriate pathway for the removal of solid wastes to the manure heap
using a wheelbarrow
• safety: foot-baths 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; fire-fighting equipment located conveniently.
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
Structure
Recommended construction
lumber
(pitch pine, plywood, chipboard), metals (galvanised roofing
material
sheets and pipes) and ceramics (tiles, wash basins, sinks).
Foundations • bricks as foundation blocks
• steel rods
Properties of materials
• concrete: mixture of gravel,
Table 17.1 summarises some materials for use in the construction of
sand, cement and water
animal housing.
• slatted floors: lumber
Floors
Lumber should be hard, strong and durable (long-lasting). Some
(greenheart, laurier)
timbers,
such as greenheart, mora and wallaba, are more durable than
• steel rods, wire mesh and
others.
Teak,
greenheart and cedar are more resistant to termite attack,
polythene sheets
whereas
Caribbean
pine, plywood and white pine are susceptible.
• concrete: gravel, sharp sand,
plastering sand, cement
Some timbers, such as Caribbean pine and white pine, rot readily when
partially buried in the soil, so should be avoided for use as posts. The
Walls
• clay or concrete blocks,
cement, plastering sand
durability can be improved by treatment with paint, creosote, solignum,
• lumber, iron/steel rods, wire
pressure or heat.
mesh
Iron and steel are hard, strong, resistant and heavy. They have tensile
• lumber (rafters, laths): mora,
Roofs
strength (do not break under tension), so are used as the framework
greenheart or Caribbean pine
for concrete posts and beams, decking or raised floors and roofs. These
• iron/steel, purlins, galvanised
metals do rust when exposed to the atmosphere and rain, so they are
or aluzinc roofing sheets
treated with zinc oxide to prevent corrosion (galvanised). The coating
prevents rusting for some time, after which protection is given by regular
Table 17.1 Recommended construction
painting.
materials for animal housing.
253
Section C Animal Production
Name THREE construction materials that are
imported into the Caribbean region,
r•
What are the advantages of using galvanised iron/
steel sheets for roofing?
Aluminium and zinc are also hard and strong metals, but they are lighter and
do not rust so are more durable. They are moulded into roofing beams and sheets,
frames for doors and windows, and louvre blades for windows.
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 which is sloped
for ease of cleaning and washing.
17.2 Housing for broilers, layers and rabbits
eaves extended to keep out the rain
Figure 17.2 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 to 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
This type of system is commonly used for the rearing of broilers and layers. In a
deep litter system ► deep litter system, poultry are provided with litter material to a depth of 10 to 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 to 5 birds per m 2 for
broilers and 3 birds per m 2 for layers. In addition, perches are provided for roosting
and the layers have nest boxes for egg-laying.
ii
F
.►
Figure 17.3 Deep litter system perches (left) and nest boxes for layers (right).
254
17 •
Housing
Battery systems
battery system ►
ITO6
State FOUR features of poultry pens.
How much floor space would a farmer need in
1
order to keep 50 broilers in a deep litter system?
List the features of a battery cage for an
individual hen.
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.
Figure 17.4 The battery
A cage for a single hen should measure 36 cm system: layers in communal
long, 30 cm wide and 36 cm high. Cages designed cages.
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.
Rabbits
rabbitry ►
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 cm 2 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 well-ventilated
• protect the rabbits from rain, sun and cold draughts
• allow droppings to fall through the wire mesh floor: to the ground in outdoor
hutches, to deep litter beneath in indoor hutches, or on to a tray for droppings
beneath the wire mesh floor
• are durable and easy to clean.
rainproof roof
wall facing the wind
cages
pole
State the dimensions of an individual hutch and a
communal hutch.
droppings fall through the wire floor
nuru
Suggest why it is usual for a hutch to be
positioned 1 m above the ground.
supports to keep vermin away
Figure 17.5 Rabbit hutches in a shelter.
255
Section C Animal Production
1
17.3 Bee production and fish farming
Bee production
apiculture ►
apiary ►
Figure 17.6 A top bar hive.
Bee-keeping and the production of honey, known as apiculture, 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 provided that 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.
Traditionally, hives have been made out of local materials,
such as bark, clay pots, straw or woven baskets.
There are three basic choices of hive:
• local-style fixed comb: clay pots can be used for these
hives; several pots grouped together and placed on a
stand will provide somewhere for the bees to build a
comb and also a brood box, where the queen bee lays
her eggs
• top bar hive: usually made of wood, but can be
constructed from bamboo, straight sticks, woven
matting; needs to be plastered with mud or cow dung to
make waterproof and to prevent entry of ants and hive
beetles; the top bars are made of bamboo or straight
sticks and a stick of wax is fixed to the underside of the
bars to guide bees to build their comb; this hive can be
hung from a tree and moved from place to place
• frame hive (moveable comb): typically constructed of wood; some are
concrete and are cheaper than wooden hives; this hive is used by commercial
beekeepers.
Frame hive
A frame hive consists of:
• a floor forming the base of the hive, with a landing platform for the bees to
enter the hive
• a brood box containing frames
• a super with frames which form the honey store; this is separated from the
brood box by a queen excluder
• a roof,
outer cover
frame
honey
supers
brood
chamber
• ••
ce
.e .,^,.,r
bottom board
bottom board
10-frame hive
Figure 17.7 a) A frame hive.
256
b) The construction of a frame hive.
Side view of the hive
17 Housing
Cal
Name THREE types of hive.
1
Explain the function of a queen excluder.
1
What is the purpose of a brood box?
Practical activity:
Visit an apiary and make notes on
the siting of the hives. If possible,
observe the bee-keeper handling
the bees or extracting honey
from the combs. Find out if the
bee-keeper harvests any other
products, such as wax, from the
hives.
The brood box and the super are similar in construction, but the brood box is
usually deeper. Inside the brood box are the frames on which the queen lays her
eggs. The super also contains frames, but these are where the bees store food and
honey. The queen excluder prevents the queen from getting into the super and
laying eggs there. The excluder also makes it easier for the bee-keeper to extract
honey. The frames are made of wood surrounding a wax foundation on which
bees build the cells of the comb in which the honey is stored. The frames are
held the correct distance apart in the brood box and in the super by metal ends.
This enables the frames to be removed for inspection and for the extraction of the
honey from the super.
To begin with, one brood box and one super are sufficient, but as the bee colony
increases in size more supers can be added.
Although a frame hive is more expensive to buy or make, it is more convenient
for the bee-keeper and makes extraction of honey easier. Oil drums and plastic
containers can be used and frames can be made to fit these.
Protective clothing must be worn by people dealing with bees, so that there
is less risk of being stung. The head and face are protected by a hat and veil. A
bee suit, to which hat and veil can be attached, is also desirable. Bee stings can
penetrate jeans and thin socks, so if a bee suit is not available then thick clothing
should be worn. Hands can be protected by gauntlets which extend to the elbows.
In addition to the hives and protective clothing, equipment is needed for the
extraction and marketing of honey. If the honey is to be marketed commercially,
then steel or plastic extractors are required.
Fish farming
aquaculture ►
Aquaculture refers to the cultivation of selected aquatic plants and animals in
water in specially designed areas, using appropriate management principles and
techniques.
There are three main types of aquatic environment:
• freshwater farming: tilapia rearing; shrimp farming; cascadura rearing; rearing
of black conches; cultivation of water lilies; ornamental fish farming
• brackish water farming: prawn farming; oyster farming; tilapia farming
• salt or seawater (marine) farming: shrimp farming; sea moss cultivation;
lobster farming; 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 (land, water, humans) more effectively
• means that fish and fish products do not have to be imported.
In establishing a freshwater aquaculture system, several factors should be
considered, e.g. the types of fish to be farmed (such as tilapia or cascadura), the
production system and the types of ponds.
Production systems may be intensive with high stocking rates (10 to 40 fish/m3),
semi-intensive with a moderate stocking rate (4 to 5 fish/m 3 ), or extensive with a
low stocking rate (1 to 2 fish/ 20 m3).
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 and promotes growth of pondweed, which
oxygenates the water as well as providing food for the fish. This system is cheap as
it does not require much labour or additional food for the fish.
257
Section C Animal Production
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 growth of blue-green algae that can
be toxic to fish. Algal blooms can also result in blockage of pipes and waterways.
Ponds may be concrete or earthen. The best earthen ponds are of a clay soil
type. Those built on other soil types need to be lined with durable plastic and
compacted to prevent leakage. Most will be 1.5 to 2 m in depth, the number and
size depending 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.
Figure 17.8 The layout of ponds in an intensive fish farm (an aerial plan).
There are government aquaculture project sites, such as the Sugar Cane Feeds
fingerlings ► 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 to 5% of
their body weight in feed daily. They can convert 1.8 to 2.2 kg of feed into 1 kg of
bodyweight. Tilapia should be fed at least twice daily.
258
17 • Housing
Setting up
When setting up a fish farm, the following management practices need to be
considered:
• protection: fences and bird nets protect 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 need to have equipment to
aerate (oxygenate) water in the pond
• fertilising: fertilisers are added to water to encourage 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
• 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.
t
1
e
0
11.
is
ds
th
he
ies
or
,ds
of
of
Name TWO types of fish that can be farmed in
fresh water.
State which conditions are controlled in intensive
fish farming systems.
How can fish farmers protect their ponds from
predators?
State THREE observations that a fish farmer
needs to make on a daily basis.
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 if there
are any proposed government-
Figure 17.9 An intensive fish farm — note the nets over the ponds.
Harvesting
Harvesting takes place when fish have reached their ideal market weight (0.5 to
0.75 kg for tilapia). The time taken to reach this weight depends on the age of the
fingerlings, feed quality and feeding regime. Generally, 2-month-old fingerlings
raised in ponds can be harvested in 4 to 5 months.
After harvesting, live or chilled fish are sold directly to consumers or taken to
district markets. Dressed fish or fish fillets are supplied to supermarkets, restaurants,
hotels or exported to niche markets abroad.
Coastal aquaculture
Coastal ponds can be used to farm marine shrimp, but this depends on the tides
filling and emptying the ponds. Marine shrimp and oysters are farmed intensively
in the Bahamas, but 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.
funded projects to encourage the
development of aquaculture.
259
Section C Animal Production
• Several factors are considered in the design and construction of buildings to
house livestock, e.g. purpose, orientation, ventilation, sanitation and safety.
• Local and imported materials are used in the construction of animal housing.
• Construction materials are best suited for specific purposes, such as foundations,
floors, walls and roofs.
• Housing for broilers and layers may be in deep litter systems or battery systems.
• In deep litter systems, local materials are used as litter. The space per bird is 900
cm' for broilers and 8100 cm 2 for layers. Layers are provided with perches and
nest boxes.
• In a battery system, the cages are wire mesh with troughs for food and water
and a sloping floor for easy egg retrieval.
• Hutches for rabbits are constructed of wire mesh, or wood and wire mesh if
they are to be outdoors. They should be well-ventilated, protecting animals
from the weather and be easy to clean.
• Bee-keeping is known as apiculture and is a useful form of agriculture in
developing countries.
• Hives can be: fixed comb, top bar or frame. The most usual commercial hive is
a frame hive made of wood.
• Frame hives consist of a floor, a brood box, supers and a roof.
• Hives can be placed in orchards, gardens and vegetable plots, where there are
sources of nectar and pollen.
• Protective clothing should be worn by people handling bees.
• Aquaculture is the cultivation of selected animals and plants, such as tilapia,
shrimps, oysters and prawns, in water.
• Aquaculture in a developing economy increases fish production, promotes
employment, uses local resources more effectively, and satisfies the nutritional
needs of the population.
• Type of fish, source of fingerlings, feeding, harvesting and marketing procedures
need to be thought about when setting up aquaculture projects.
ITQ1 Good ventilation is needed to disperse heat, foul odours and moisture. It
also promotes air circulation and temperature control.
1102 Any four from: foot baths at entry points; covered drains; covered
drainage channels; wide exits for speedy removal of animals; fire-fighting
equipment.
IT03 Sloping floors enable animal pens and housing to be cleaned and washed
down easily.
1104 Lumber (teak, mahogany, cedar), aggregates (sand, gravel, cement) and
metals.
1105 Galvanised roofing sheets do not rust when exposed to rain and to the
atmosphere.
1106 Any four from: well-drained; be at least 10 m wide; oriented to keep out
the weather; made of wood with a metal roof; have a sloping floor; a
brick wall to keep in the litter; wire mesh above; draught-proof; suitable
lighting; a wide doorway; suitably ventilated.
2
2
1107 He would need 10 m 2 at a stocking density of 5 birds per m or 12.5 m if
the stocking density was 4 birds per m2.
1108 Battery cages should be made of wire mesh, with a trough for food and
water, a sloping floor and a removable tray to collect the droppings. It
should be 36 cm x 30 cm x 36 cm.
260
17 •
Housing
1109 An individual hutch should be 75 cm long x 60 cm wide x 40 cm high. A
communal hutch should be 120 cm long, but the other dimensions can
be the same.
11010 At 1m above the ground, rabbits are safe from rats and mice and
droppings can fall through and be removed easily.
11011 Fixed comb, top bar and frame are the three types of hive.
11'012 The queen excluder prevents the queen moving from the brood box into
the super, where the cells store honey.
17013 The brood box is the home of the bees and is where the queen lays eggs
and young bees are reared.
.ITQ14 Tilapia and cascadura can be farmed in fresh water.
.11015 The conditions controlled in an intensive system are water quality,
temperature, pH, and oxygen levels.
11116 Nets spread over the top and fences around the ponds will protect the fish
from predators.
11017 Any three from: water quality, health of the fish, behaviour of the fish
and mortality.
Examination-style I Multiple Choice Questions
1. Which of the following is a NOT a suitable construction material for the
questions
foundations of an animal house?
A concrete
B lumber
C bricks
D steel rods
2. What is the recommended stocking density per m 2 for layers kept in a
deep litter system?
A2
B 3
C4
D5
3. In a frame hive, a super is the part of the hive which:
A protects the bees from the rain
B houses the young bees
C provides a landing platform for the bees
D contains the combs in which honey is stored
4. Which of the following statements is true of an extensive fish farm?
A the stocking rate is high
B the oxygen content of the water is controlled
C it is stocked with fish from a local river
D the pH of the water is controlled
261
Section C Animal Production
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
Examples: local/regional construction
materials
teak,
nails,
tiles,
fittings,
sand,
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:
(ii) iron/steel
(iii) concrete
(i) lumber (wood)
6. (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:
(b)
tli
PART OF farm
building
Foundation
Floor
Wall
Roof
Ott
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. Describe the role of aquaculture in a developing economy.
9. Describe the structure of a wooden frame hive and explain how each part
is adapted to its function.
ih
1*
RN
262
n ab
By the end of
this chapter
you should be
able to:
V
name the breeds of the different classes of animals reared in the
Caribbean
explain the purpose of the different breeds
describe how characteristics are inherited in animals
describe the different breeding systems in animal production
understand the advantages of cross-breeding
describe how genetic improvement can occur
describe the process of artificial insemination
discuss the value of artificial insemination
define the terms used to describe the reproductive processes in
animals
state how eggs are formed and incubated in poultry
explain embryo transfer and state its benefits
understand the significance of biotechnology in animal production.
i
/
3
3
3
3
3
3
3
3
3
Concept map
Animal genetics I I
genetics,
Animal genetics, breeding and reproduction
Breeding
I
Breeds of
animals
Reproduction
I
I
Terms used
Artificial
insemination
I
Egg formation
in poultry
Frozen semen
Candling
Oestrus synchronisation Llncubation:
Lsjgns of heat
natural
Purposes of
different breeds
artificial
Inheritance
Breeding
systems
Genetic
improvement
Embryo
transfer
Genetic
engineering
3enes:
genotype
phenotype
homozygous
heterozygous
dominant
recessive
;i mole crosses
-Cross-breeding:
heterosis
disease resistance
improved production
Animal identification
Record keeping
Selecting animals
Benefits
FBenefits
Concerns:
ethical
religious
- Upgrading
-Inbreeding
263
Section C Animal Production
18.1 Breeds of farm animals
There are several classes and breeds reared in the Caribbean (see Table 18.1).
Class of farm
animal
Cattle
Pigs
Goats
Sheep
Rabbits
Poultry
Breeds in use in the Caribbean
Dairy: Jersey, Jamaica Hope, Holstein.
Beef: Jamaica Red, 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, Byline
or Hybrid crosses.
Broilers: Vantress Cross, or other hybrid crosses, e.g. Peterson,
Shaver.
Table 18.1 Classes and breeds of farm animals reared in the Caribbean.
What breed of poultry would a farmer choose for
egg production?
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 cross-breeding
(when two different breeds are bred). 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
resistant to some diseases. Similarly, Jamaica
Red and Jamaica Black cattle were developed Figure 18.1 A Zebu bull.
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 have been exported
to other Caribbean countries. The Barbados
Blackbelly sheep are reared for their meat and
are probably derived from sheep brought by
settlers to the islands. They are tolerant of heat
and have coats of coarse hair, not wool.
Figure 18.2 A Jamaica Hope cow.
Figure 18.3 A Jamaica Black cow.
Figure 18.4 A Jamaica Red bull.
cross-breeding ►
MI
Name THREE breeds of dairy cattle and three
breeds of beef cattle.
1
11
264
Figure 18.5 The Buffalypso breed.
18 - Animal genetics, breeding and reproduction
18.2 Uses of different breeds of farm animals
The major roles of animals on the farm are to:
• provide food
• supply power for ploughing (bullock, buffalo, mule) and transport (mule,
donkey, buffalo, horse, bullock)
• supply raw materials
• create employment opportunities and provide farm income
• provide recreation and serve as pets
• provide opportunities for agricultural research.
The provision of food involves the production of milk, meat and eggs. The major
classes and breeds producing these commodities are listed in Table 18.2.
Commodity
Animal class
Breed
Milk
• Cows
• Goats
• Sheep
Meat
• Cattle (beef)
Jamaica Hope, Jersey, Holstein.
• Toggenburg.
• No specific breeds named but sheep's
milk can be used to make cheese and
yoghurt.
• Jamaica Black, Jamaica Red, 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.
• Pigs (pork, bacon)
• Sheep (lamb,
mutton)
Eggs
• Poultry (chicken)
• Rabbits
• Poultry
•
Table 18.2 The sources of milk, meat and eggs.
Supply of raw materials
Figure 18.6 White Leghorn chicken.
ll
State THREE major roles of animals on a farm.
Which breed of pig is chosen for the production
of bacon?
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.
Raw materials from farm animals
include:
• dung/droppings from all classes of
animals: used as manure
• skin, pelts, leather: the skins can
provide leather and pelts are used
for manufacture into garments
and furniture; sheep are not kept
in the Caribbean for their wool as
the wool breeds do not suit the
climate; goats produce hair for
carpets and cloth, in addition to
their skins for leather
• dung of pigs and cattle: used to
generate biogas.
Figure 18.7 Landrace pig.
Pets
Many 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 also protect farm animals from predators and vermin.
265
Section C Animal Production
18.3 Animal genetics
To appreciate the way in which breeds of farm animals may be improved, we need
to understand how different characteristics are inherited. Refer back to Chapter
11 and revise cell division, the nature of genes and chromosomes,
and the common terms used (genotype, phenotype, homozygous,
heterozygous, dominant and recessive).
In Chapter 11, genetic inheritance in plant breeding was
explained. Meiosis occurs during gamete formation and introduces
variation, so that after fertilisation the offspring are not genetically
identical to each other or to their parents. In the same way that
different varieties of crops have different genotypes, so do different
breeds of an animal species.
We can increase the productivity of a plant crop or a breed of
animal by crossing individuals with favourable characteristics in a
breeding programme. For example, in the development of Jamaica
Hope cattle, Jersey cattle with high milk yields were crossed with
Zebu cattle from India and Holstein cattle, also high milk yielders,
from Europe. The resulting breed produces a high milk yield on
the poor pastures associated with the tropical climate of the region.
These cattle tolerate heat and have a high resistance to ticks and the
diseases they carry.
Inheritance and coat colour
The way in which simple Mendelian inheritance works can be
shown by considering coat colour in two breeds of cattle. Lincoln
Red cattle have red coats and Hereford cattle also have red coats
but white faces. Figure 18.8 shows a Hereford cow. The presence of the white
face is due to the dominant allele (W) of a gene. Hereford cattle are homozygous
dominant for this characteristic (WW).
When a farmer mated Lincoln Red cows with a Hereford bull, the offspring all
had white faces. The farmer kept one of the male offspring of this cross. When it
was mated with Lincoln Red cows, half the offspring had white faces and half did
not.
We can show what is happening by using genetic diagrams. Let W represent
the dominant allele for white face and w represent the recessive allele (this does
not result in a white face). The genotype of the Lincoln Red cow is ww and the
genotype of the Hereford bull is WW. The diagram in Figure 18.9 shows us what
is happening in terms of genes.
If a homozygous Lincoln Red cow is now crossed with a heterozygous Hereford
bull(Ww) we get offspring as shown by Figure 18.10. Half the offspring will have
white faces.
Figure 18.8 Hereford cow — note the white face.
Define the terms genotype and phenotype.
It
What is a gene?
Explain the terms heterozygous and homozygous.1
If a heterozygous cow was mated with a
heterozygous Hereford bull, what are the chances
of the calf having a white face?
Lincoln Red cow x Hereford bull
ww
WW
Gametes w
Gametes
Lincoln Red cow x Heterozygous Hereford bull
ww
Ww
Gametes w
W
W
w
Ww
Ww
w
Ww
Ww
Genotype of offspring: Ww
Phenotype of offspring: All have white faces,
because they have the dominant W allele.
Gametes
w
w
Ww
WW
w
Ww
WW
Genotype of offspring: ww and Ww in the ratio 1:1
Phenotype of offspring: Half will have white faces
and half will not.
li
266
Figure 18.9 Diagram showing a
Figure 18.10 Diagram showing a
mating between a Hereford bull(WW)
and a Lincoln Red cow(ww).
mating between a Hereford bull(Ww)
and a Lincoln Red cow(ww).
18 . Animal genetics, breeding and reproduction
18.4 Breeding systems in animal production
Breed
breed ►
breeding system ►
heritability ►
continuous variation ►
variety ►
cultivars ►
A breed is a group of animals of the same species which 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 a breeder wants to produce more 'suitable' animals, he 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 put on poor pasture their yields will
not be as high as those fed on a better diet. If the breeder is hoping to breed an
animal that will increase its productivity, he needs to know what proportion of the
desired characteristic is influenced by genotype, rather than by the environment.
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 breed from
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 ►
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.
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 each other. 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
life span.
Upgrading
upgrading ► Upgrading involves the crossing of 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 found in Europe, do not always adapt
267
Section C Animal Production
well to a tropical climate. Their food sources may differ and they cannot tolerate
the heat as well as the local breeds. They also have less resistance to the pests and
diseases which 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 the local breed. A good example is development of the Jamaica
Hope dairy cattle and the Jamaica breeds of beef cattle.
Back-crossing
back-crossing ►
tr
Explain what is meant by the term breed.
1
What is cross-breeding and how does it differ
from inbreeding?
Describe ONE example of upgrading which 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 has
probably been more frequently applied in the development of crop plants. This
type of cross is carried out to obtain offspring which are similar to the parent with
the desirable characteristic.
Homozygous parent x Heterozygous parent
In a cross between a heterozygous
Hereford bull and a Lincoln Red cow
W
Ww
w
w
described in Figure 18.10, half the Gametes w
offspring would be homozygous (ww)
Gametes
W
W
for the recessive gene and not show the
W
Ww
WW
white face associated with the Hereford
w
Ww
Ww
breed. It would be easy to select these
Genotype of offspring: WW and Ww
offspring from the rest. If, however, the
Phenotype of offspring: All with white faces.
breeder wanted to keep the dominant
In this cross, the breeder would not be able to
allele, then the heterozygous offspring
distinguish between the two genotypes.
would need to be back-crossed with the
homozygous dominant parent, as shown Figure 18.11 A back-cross: the
in Figure 18.11.
heterozygous offspring(Ww) is crossed
In Figure 18.11, the characteristic is with the homozygous parent(WW).
a visible one and controlled by a single
gene, but most characteristics are not
easily visible and are controlled by a number of genes.
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.
18.5 The advantages of cross-breeding
Hybrid vigour (heterosis)
hybrids ►
hybrid vigour, heterosis ►
Parent genotypes: Breed X x Breed Y
AAbb
aaBB
Gametes
Ab
aB
Gametes
Ab
aB
AaBb
AaBb
aB
Ab
AaBb
AaBb
Genotype of offspring: AaBb
Phenotype of offspring: Potential to produce large
litters with a high percentage survival.
Figure 18.12 A genetic cross
diagram demonstrating hybrid vigour.
268
Cross-breeding involves mating animals from different breeds of the same species,
and it combines the genes of the two breeds. The resulting offspring are referred to
as hybrids and there is 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.
Most desirable characteristics are controlled by dominant genes and hybrid
vigour is due to the 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.
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 18.12.
18 Animal genetics, breeding and reproduction
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 which 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.
1
What is a hybrid?
The Jamaica Hope breed is an example of selection for disease resistance (see
page 264). Zebu cattle have some resistance to parasitic ticks and the diseases
they carry. When Zebu were crossed with Jersey cattle, the resulting hybrids also
showed increased resistance to ticks.
I mproved production
What is meant by hybrid vigour?
1
Why is disease resistance in farm animals
important?
1
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, so continuing the improvement of the stock.
18.6 The principles of genetic improvement
In attempting to improve breeds of farm animals it is necessary to:
• identify desirable characteristics
• keep accurate records of animal performance
• select animals for breeding.
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 which 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
performance testing ►
Performance testing involves comparing the productivity of animals kept under
the same conditions. It applies to characteristics which can be measured, such as
milk yield, number of offspring and survival rates. Records of performance are
269
Section C Animal Production
useful, not only for identifying which animals are good producers but also for
the farm accounts. The benefits of record-keeping have already been described in
Chapter 7.
Embryo transfer
embryo transfer ►
The selection of animals for breeding is mainly based on their performance. Good
dairy cows have traditionally been used for breeding, but the number of calves
produced in their lifetime is about eight, of which half 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
progeny testing ►
Desirable female characteristics, such as 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, where one bull's semen
can be used to fertilise many cows, means that a good bull may produce thousands
of offspring in a year.
Heritability
i
Give TWO reasons why it is important to keep
records of the performance of farm animals.
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, they will have some idea as
to whether selection for improvement of that characteristic is likely to be successful.
The higher the percentage heritability is, the greater the chance that selection for
the characteristic will result in improvement. For example, post-weaning 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.
18.7 Artificial insemination in farm animals
mating ►
artificial insemination (Al) ►
"i
Figure 18.13 Collecting semen from
a pedigree bull.
Mating in livestock farming refers to the bringing together of a mature male and
female animal of the same species for the purpose of breeding. Female animals
which 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 in the process of artificial
insemination (Al). This is a technical process which 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 ejaculate into an artificial vagina which collects the
semen. A single ejaculation can have a volume of 3.5-5.0 cm' and contain 15 x
10 6 sperm. The sperm count of the semen is determined and quality control checks
detect any abnormalities or diseases.
The semen is then diluted with a solution containing:
• sugar
• salts which 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 cm 3 to 0.5 cm', and packed into
disposable plastic straws. The straws are stored by freezing in liquid nitrogen at
270
18 • Animal genetics, breeding and reproduction
-196°C. The straws can be used
Define artificial insemination.
e
What is added to the semen when it is diluted?
to service hundreds of female
animals (cows, ewes, sows)
worldwide.
Before AI is carried out, the
straw containing semen is thawed
and 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 Figure 18.14 Artificial insemination of a
cow.
beyond the cervix into the uterus
(see Figure 18.14).
For AI to be successful, it is important
rt
that signs of heat are detected and that
1
insemination takes place at the best time. In cows, oestrus (the period on heat)
lasts between 12 and 16 hours. The optimum time is between 5 and 20 hours after
) the beginning of oestrus, because ovulation occurs 10 to 12 hours after the end of
I
oestrus.
18.8 Advantages and disadvantages of
artificial insemination
Figure 18.15 Semen in a storage
straw.
The main advantages of AI are as follows:
• farmers are more motivated to keep records
• an improvement or upgrading of the farmer's stock of animals
• it removes the risks involved in rearing dangerous male animals, e.g. 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 prevented from physical injury during
mating due to 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.
The disadvantages include:
• the cost of setting up and maintaining the necessary facilities
• the requirement for special equipment and skilled personnel, including trained
inseminators
• the maintenance of semen storage and inspection facilities: the frozen semen
has to be monitored regularly to detect loss of viability of the sperm
• failure of the insemination to result in a pregnancy: farmers may not respond
quickly enough to the signs of oestrus in the females; cows may come on
'silent' heat which is not easily detected by the farmer but would be readily
identified by a bull.
List TWO
TWO advantages and two disadvantages of
artificial insemination.
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.
271
Section C Animal Production
18.9 Terms used in animal reproduction
The oestrous cycle
oestrous cycle ►
oestrus ►
ovulation ►
2. oestrus
3. metoestrus
1. proestrus
4.dioestrus
Figure 18.16 The phases of the
oestrous cycle.
The oestrous cycle is a sequence of events, controlled by hormones, occurring in
female mammals. It 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
ti me during which the female farm animal is sexually receptive to the male farm
animal. 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.
Ovulation is the release of an ovum from the ovary and is closely associated with
the heat period. It usually occurs during oestrus or shortly after. Mating during this
ti me can result in fertilisation and pregnancy.
The oestrous cycle (see Figure 18.16) can be divided into four phases:
• proestrus: 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): influenced by oestrogen; causes the female to be
sexually receptive for mating; may result in ovulation
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; 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 among the classes
of livestock (see Table 18.3).
Class of
Livestock
Cattle : Cow
Length of
oestrus cycle
(days)
range
avg.
21
18-24
Duration of
heat or oestrus
(hours)
avg.
range
19
12-28
Time of ovulation (hours)
avg.
12
Sheep : Ewe
17
14-20
38
24-48
38
Pig: Sow
21
18-24
60
24-96
36
Goat : Doe
20
19-21
39
24-96
36
range
10-16 after end of
oestrus
36-40 after
beginning of oestrus
30-40 after
beginning of oestrus
12-36 after
beginning of oestrus
Table 18.3 The oestrous cycles of different classes of livestock.
Signs of heat
When female farm animals come on heat, they usually display signs which are
recognised by the farmer (see Table 18.4). 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.
This is particularly relevant to cattle because milk production depends on the cows
producing calves.
272
18 Animal genetics, breeding and reproduction
Cattle: Cow
Duration of
heat
12-24 hours
Goat: Doe
24-36 hours
Sheep:
Ewe
Pig: Sow
About 36
hours
2-3 days
Class of
animal
Signs of heat (oestrus)
Restless; swollen and/or reddened vulva; slimy
mucus discharge from the vulva; persistent mooing
or bellowing; allows other cows to mount her; drop
in milk yield; loss of appetite.
Restless; vulva becomes enlarged or swollen; slimy
mucus discharge from the vulva; persistent bleati '
stands to be mounted by the buck; vigorous shak'
of the tail.
Does not often show visible signs but rams can
detect when ewes are on heat.
Restless; grunting; vulva becomes reddened and
swollen; slimy mucus discharge from the vulva;
stands to be mounted by the boar.
,.,„.
_
--„i
_
Table 18.4 Duration of heat and signs of heat in some female farm animals.
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 sperms 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 wall and eventually develops into the offspring.
Gestation
Class of
livestock
Cattle: Cow
Sheep: Ewe
Pig: Sow
Goat: Doe
Rabbit:
Doe
'
gestation ► Gestation is the period between conception (fertilisation) and the birth of the
young (parturition). It varies in length with the different classes of farm animals
(see Table 18.5).
Length of gestation
Throughout the gestation period, pregnancy is maintained by the corpus luteum
period (days)
in
the ovary which produces the hormone progesterone.
Average
Range
The farmer can recognise that his animals are pregnant because:
280
277-283
• there is an absence of heat (the non-pregnant cow would show signs of heat
148
145-151
19-23 days after insemination)
114
110-117
• the abdomen changes in size, becoming wider or 'bellying down'
150
147-153
• the mammary organs (udders, teats, milk veins) develop.
28-32
30
Table 18.5 The gestation periods of
some farm animals.
fetus ►
The farmer can determine pregnancy in cows by getting a veterinarian or a trained
livestock technician to palpate the uterine horns 3 to 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 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.
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, now called a fetus.
Waste materials from the fetus pass across the placenta into the blood of the mother.
273
it
r
Section C Animal Production
Parturition
parturition ►
Figure 18.17 A newly born lamb.
Distinguish between the oestrous cycle and
oestrus.
kindling ►
rr i
Define ovulation.
Parturition (the birth process) occurs at the end of the pregnancy and is the time
when the female 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, seek out a quiet area,
try to urinate frequently; in cows, there is a thick mucus discharge from the
vulva
• uterine contractions occur as the result of the secretion of the hormone
oxytocin
• the cervix and pelvic region dilate under the influence of relaxin
• the offspring is delivered through the birth canal
• the placenta (after-birth) is delivered shortly after the offspring.
The farmer or a farm attendant should always be present at parturition to help.
It may be necessary to:
• remove mucus from the mouth and nostrils to enable the young to breathe
easily
• dry the young if the mother has not already done so
• make sure that the umbilical cord is not wrapped around the neck of the
young
sever
the umbilical cord, using the correct procedures
•
• make sure that the mother suckles the young soon after birth so that they get
the colostrum (first milk after parturition) which provides antibodies.
Kindling
Kindling is the te rm 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 5 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 3 days before kindling is due.
rr
List THREE signs of heat shown by a cow.
Farrowing
farrowing ► Farrowing is parturition in pigs and takes place about 115 days after mating. Ttvo
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
rr^
to 8 hours, with piglets delivered at 10 to 20 minute intervals. When all piglets
How long is the gestation period of a pig?
have been delivered, the placenta is expelled.
rrc
18.10 Egg formation and incubation in poultry
Why is colostrum so impo rtant?
Egg formation
oviduct ►
Practical activity:
Visit livestock farms and, if
possible, observe signs of heat in
the farm animals.
germinal disc ►
infundibulum ►
274
Egg formation takes place in the reproductive tract of a hen which consists of a
single ovary and oviduct (see Table 18.6). The oviduct is a long tube divided into
several sections, each with 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).
An ovary can contain up to 12000 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 18.6.
18 • Animal genetics, breeding and reproduction
ova
Part of oviduct
Infundibulum
Time spent
Magnum
About 3 hours
Isthmus
About 1 hour
Uterus/shell
gland
18-20 hours
Vagina
1-10 minutes
infundibulum
magnum
Vent/cloaca
vent/cloaca
Functions
Engulfs the yolk and deposits it into 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 only stays here for a short time
during which it is rotated through 180° so
that it is laid large end first.
The completed egg is expelled through this
opening.
Table 18.6 The functions of the parts of the oviduct of a hen.
Figure 18.18 The reproductive
tract of a hen.
incubation ►
Incubation
Incubation is the process of providing the necessary conditions for the hatching
of 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 'farmsupport' 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
Figure 18.19 A hen with a brood
of chicks which have been incubated
naturally.
This system is still favoured by small farmers in rural communities. It involves the
use of a broody hen which has just completed a laying-cycle. She sits on a clutch
of 10-15 eggs in her nest and provides them with warmth for the development of
the embryos and their eventual hatching.
There are several factors which can influence this process, including:
• nesting environment: a cool, quiet, well-ventilated and darkened area
encourages the hen to lay and incubate
• curvature of the nest: the hen moves her body and feet in a circular manner
to prepare a nest that is bowl-shaped; this 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 development of the embryos; the hen's
normal body temperature is 39.4°C and this provides the warmth; she sits on
the eggs most of the time, except for short periods when she feeds, defecates
and exercises
• turning the eggs: essential to prevent the yolk sticking to the shell and causing
abnormalities or 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.
Artificial incubation
artificial incubation ►
Artificial incubation is a scientific method of producing 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
275
Section C Animal Production
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: must be cleaned, sanitised and prepared before the eggs are placed
in them; should be checked to see that all automatic parts and systems are
working properly; should have a reliable source of power (gas, oil, electricity)
for the generation of heat; must provide adequate space for each egg and chick
that emerges (25 cm' per egg/chick)
• fertile eggs: usually large with an average weight of 55 g; must be checked for
cracks and abnormalities; are wiped clean using a soft, damp cloth containing
a mild disinfectant; then they are placed in the incubating tray with the large
ends on top
• heat supply: powered by gas, oil or electricity; temperature controlled by
a thermostat; initial temperature maintained at 38.5°C for weeks 1 and 2;
temperature is increased to 39.5°C in week 3
• humidity: maintained around 60% to stop rapid loss of moisture by
evaporation through the porous shells of the eggs; ensures normal embryo
development and reduces mortality
• ventilation: well-ventilated for exchange of gases through the porous eggshell; oxygen is needed and carbon dioxide must be removed
• turning the eggs: prevents yolks from sticking to the shells; may be done
manually in small, box-type incubators; mechanical turning is achieved by
automatic devices which constantly tilt the trays.
Figure 18.20 A commercial
incubator.
1r..
In which part of the oviduct does fertilisation take
place?
it•---
Candling
List the parts of the oviduct of a hen.
candling ► Candling is the process by which eggs are tested for fertility by shining a light
through them. It gets its name from when candles were used as the light source.
The process is carried out between days 9-15 of incubation on eggs which are
being incubated artificially so that infertile and bad eggs can be removed.
Describe the ideal nesting environment for a hen
If eggs are fertile, the developing embryo will show up as a dark spot with spidersitting on a clutch of eggs.
like 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 are
rr
left in the incubator they produce the gas hydrogen sulphide and will eventually
Explain why the humidity is kept at 60% in an
explode, damaging other eggs.
artificial incubator,
1
18.11 Embryo transfer
r
embryo transfer ► Embryo transfer is the technique of removing embryos from the reproductive
tract of a donor female animal and implanting them into the reproductive tract of
] another female animal (the surrogate). The technique has been developed over the
last 30 years and enables animal breeders to select female animals with desirable
Practical activities:'
characteristics, use their eggs to produce embryos which carry the desired genes,
1. Set up a small-scale incubator
and implant the embryos into surrogate mothers. Embryo transfer is commonly
used in cattle.
and try incubating some eggs.
2. Visit a local hatchery.
Embryo transfer in cattle
Usually the donor cow will not carry the embryos through pregnancy, so she
is injected with hormones that cause her to release more eggs than normal
(superovulate). She is then artificially inseminated and the resulting embryos are
allowed to develop for 6 to 8 days, by which time they will have entered the
uterus. A catheter is inserted, under local anaesthetic, through the vagina into the
uterus. The uterus is flushed out with a fluid and about five embryos are collected.
This non-surgical process can be repeated six times a year. If embryos are removed
earlier, before they have reached the uterus, they have to be removed surgically
from the oviduct.
276
1 8 Animal genetics, breeding and reproduction
1. Donor cow superovulates and
releases eggs which are
fertilised by Al
2. Six embryos are removed
from the donor cow
4
4
♦
4
4
3. Each embryo is put into 1111111R1111t 1111‘4114,4114M
a surrogate cow
embryo
Figure 18.21 The stages involved in embryo transfer.
After embryos have been removed, their sex is determined: female embryos are
selected for use in dairy breeds and males in beef breeds. They are then transferred
into surrogate cows, which are at the same stage of their oestrous cycle as the
donor cow. This ensures that the embryo is provided with the right environment
for implantation and further development. If necessary, the oestrous cycle of the
surrogate can be synchronised with that of the donor by using hormones.
As an alternative to the transfer of embryos, eggs can be collected from the
donor and cultured for 5 days in a laboratory. They are fertilised with sperm in the
laboratory (in vitro) and cultured for a further 5 days before being transferred to
the surrogate cows.
The transfer of embryos into surrogate cows can be done surgically or nonsurgically. In the surgical method, a fine pipette is used to insert the embryo into
the uterus through a small hole made by a needle. The non-surgical method
involves placing a catheter into the uterus via the vagina. The success rate of the
surgical method is higher.
The benefits of embryo transfer
Embryo transfer benefits the production of livestock in the following ways:
• improvements to the herd: desirable characteristics can be introduced fairly
rapidly; it is easier to combine selected characteristics in males with selected
characteristics in females
• sex determination of the embryos
some cells are taken
before implantation: this results in
from the sheep
(not egg cells)
embryos of the required sex being
used , i.e. females for dairy herds and
begins to develop
as an embryo
males for beef herds (saves time and
money in building up a herd)
• cheaper than importing an animal:
sheep which is to be cloned
the costs of embryo transfer are less
than those involved in buying a
embryo is
pedigree animal
Implanted
Into a ewe
•
reduces the transmission of diseases:
egg cell and cell
egg cell
I
to be cloned are
the eggs and embryos used are
fused together
examined for abnormalities and
egg cell with no nucleus
diseases
• makes use of non-pedigree females as
nucleus removed from egg cell
nucleus
surrogates: animals having difficulty
with breeding and non-pedigree
clone is born
(the clone has developed from
females can be used as surrogates and
the implanted embryo)
produce young for the benefit of the
herd.
Figure 18.22 How clones are produced.
clones ► Embryo transfer can produce animals that are genetically identical, called clones. It
is possible to remove unfertilised eggs from a cow and suck out the nuclei using a
277
Section C Animal Production
rl^ ;
fine pipette. Genetic material from a young embryo with desired characteristics can
be placed in the empty egg cell. The cell is then stimulated to divide and implanted
Why is a donor female made to superovulate?
into surrogate mothers. The resulting calves will be genetically identical.
^a
The most famous example of a cloned animal was 'Dolly the sheep', the first
mammal
to be cloned from an adult cell. A cell from the mammary gland of an
Describe how an embryo is introduced into a
adult
ewe
was
introduced
into an unfertilised egg cell that had its nucleus removed.
surrogate cow using a non-surgical method,
The resulting cell was stimulated to divide. The embryo produced was implanted
into a surrogate mother where it developed into a lamb.
List THREE benefits of embryo transfer.
18.12 Genetic engineering in livestock
production
genetically modified organism
( GMO) ► A genetically modified organism (GMO) is an organism whose genes have been
transgenic organism ► 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.
Producing genetically modified animals involves the transfer of a gene from
another organism into the genotype of the recipient animal. This means that the
characteristic that is controlled by the gene will show in the recipient.
Methods of gene transfer
Injection into an ovum
O1. An ovum is fertilised by in-vitro fertilisation
2. DNA for the desired gene is injected into the fe rt ilised ovum
3. The ovum is implanted into the surrogate mother
4. The transgenic offspring is born (it has the desired gene)
Infection of the emb ry o with a virus
virus
embryo
Implanted
(j x)
1. The emb ry o is infected with a virus which contains the desired gene
^)
2. Each cell of the emb ry o takes up the desired gene
3. The emb ry o is implanted into a surrogate mother
Figure 18.23 Gene transfer by injection of the desired gene into a fertilised ovum
(top) and gene transfer using a virus (bottom).
278
Two methods of gene transfer are
described below. See Figure 18.23 for
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 viruses: the selected gene is
first inserted into a virus; embryos
at the 4-8 cell stage are then
infected with the virus; the virus
infects the embryo and the selected
gene is added to the DNA of the
embryo's cells; embryos are then
implanted into surrogate mothers
where they develop into offspring.
18 • Animal genetics, breeding and reproduction
Examples of GMOs
Figure 18.24 Herman the Bull.
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.
In another experiment, the
human gene for lactoferrin (a
protein with anti-microbial
properties found in milk) was
inserted into a male embryo.
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.
Concerns about genetic engineering
rt
How are viruses used to introduce new genes into
an organism?
nux
Explain what is meant by a transgenic organism. 1
Practical activity:
Genetic engineering is more advanced in the area of crop breeding rather than in
animal breeding.
However, many people have expressed concerns about the effects of 'interfering
with Nature' particularly if food crops are involved. Any food that contains, or is
derived from, genetically modified organisms has to be clearly labelled.
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.
Religious views are mixed: no foods have been described as unacceptable, but
any use of genes from pigs is not acceptable to Jews or Muslims. The Catholic
Church is against the genetic engineering of embryos.
Many people also worry about genes which 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.
Carry out an internet search
for recent information on the
Benefits of genetic engineering
genetic modification of livestock.
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.
Collect information and make a
presentation to the rest of the
class.
1
279
1
Section C Animal Production
• The roles of animals on the farm are for food, power, raw materials, recreation
and pets.
• Several classes of farm animals, such as cattle, goats, sheep, pigs, poultry and
rabbits, are reared in the Caribbean.
• Breeds of farm animals developed in the Caribbean include the Jamaica Hope,
Jamaica Red and Jamaica Black cattle, the Buffalypso and the Barbados Black
Belly sheep.
• Understanding how characteristics are inherited is essential to animal breeding
programmes.
• Simple Mendelian inheritance can be demonstrated by the inheritance of a
white face in Hereford cattle. This characteristic is controlled by a single gene.
• A breed is a group of animals of the same species which have certain
characteristics in common.
• A breeding system is the mating of male and female animals chosen for their
desirable characteristics.
• Variation in the performance of the animals of a particular breed is determined;
by their genotype and the environment in which they live.
• The effect of the genes on a particular characteristic is called heritability.
• Most characteristics, such as milk yield, growth rate and carcass shape, are
determined by more than one pair of genes.
• Cross-breeding occurs when an animal is mated with another of the same
species but of a different breed. The genes from the two breeds are combined.
• Inbreeding is the mating of two animals of the same breed. The animals are
closely related and therefore genetically similar.
• Inbreeding can lead to inbreeding depression where there is a decrease in the
i mprovement of favourable characteristics and an increase in unfavourable
characteristics.
• Up-grading involves crossing native, or local, breeds of farm animals with
breeds from other regions of the world.
• Back-crossing occurs when a hybrid animal is crossed with one of its parents.
• A hybrid animal is the result of mating animals from two different breeds. These
animals often show increased fitness, known as hybrid vigour or heterosis.
• Examples of hybrid vigour in farm animals include milk yield, butterfat content
of milk, litter size in pigs and carcass weight in pigs.
• Disease resistance is shown by some breeds to certain pests and conditions;
progress has been made in selecting for disease-resistant breeds.
• The principles of genetic improvement involve the identification of desirable
characteristics, keeping careful records of animals' performance, and the
selection of suitable animals for breeding.
• Performance testing and progeny testing are both used to assess the qualities of
suitable animals for breeding.
• Artificial insemination involves the removal of semen from a male farm animal
(bull) and its use to fertilise very large numbers of female animals (cows).
• The semen is checked, diluted, frozen and stored for use when required. It is
thawed out before insertion into the reproductive tract of the female.
• Al means that the favourable genes of farm animals can be passed on to large
numbers of offspring, which will improve the productivity of the breed.
• The oestrous cycle in mammalian farm animals is a sequence of events which
results in them becoming receptive to the males during oestrus.
• Ovulation occurs during the cycle, during oestrus or shortly afterwards. If
mating occurs, then any ova in the female reproductive tract could be fertilised
and develop into offspring.
280
8 Animal genetics, breeding and reproduction
• Gestation is the period between fertilisation and the birth of the young
(parturition). The length of gestation varies in different classes of farm animals.
• The birth of the young is called parturition and is controlled by the hormones
oxytocin and relaxin. In rabbits, the term used is kindling and in pigs it is called
farrowing.
• Egg formation takes place in the oviduct of the hen after an ovum (egg cell) has
been released from the ovary.
• Albumen is added in the magnum, two shell membranes in the isthmus and
the hard shell in the shell gland. The egg is expelled from the vent (cloaca).
• In natural incubation, a broody hen sits on fertilised eggs and keeps them warm
until they hatch. This takes 21 days.
• Artificial incubation uses incubators in which fertile eggs are kept in the right
conditions of temperature and humidity until they hatch. Large numbers of
eggs can be incubated at one time in a commercial incubator.
• Candling is carried out on eggs to determine whether they are fertile.
• 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.
• In cattle, a superior cow is made to superovulate, artificially inseminated and
then the young embryos are flushed out. These are checked and then inserted
into a surrogate cow.
• The benefits of embryo transfer include improvements to the herd, choice of
sex of embryos and the fact that it is cheaper than importing a pedigree animal.
• Genes can be transferred from one organism to another in genetic engineering.
Desired genes can be inserted into the nucleus of a fertilised ovum and the
embryo is then implanted into a surrogate mother.
• Some genetically modified animals have been produced but most research has
been centred on the genetic modification of plant crops.
• Concern has been expressed about the effect that GM organisms may have on
the environment and on the health of people and animals.
t
`+
1101
Three breeds of dairy cattle: Jersey, Jamaica Hope, Holstein. Three breeds
of beef cattle: Jamaica Black, Jamaica Red, Charolais, Zebu.
IT02 Any from: Rhode Island Red, White Leghorn, Bevan Brown or Hyline or
Hybrid cross.
1103 Three from: food production, supply of power, supply of raw materials, to
create employment and provide recreation.
1104 Tamworth.
1105 The genotype is the genetic make-up of an organism, the total genes
that code for the characteristics. The phenotype is the appearance of the
characteristics as determined by the genes.
1106 A gene is a section of DNA that codes for a particular characteristic.
Different forms of the same gene are known as alleles.
1107 If both alleles for a gene are the same, the organism is said to be
homozygous for that characteristic. If the two alleles are different, the
organism is said to be heterozygous.
1108 A 75% chance of the calf having a white face: calves with white faces:
calves without white faces will be in the ratio 3:1.
1109 A breed is a group of animals of the same species which have certain
characteristics in common.
11010 Cross-breeding occurs when an animal is mated with another of the same
species but of a different breed. Inbreeding occurs when animals of the
same breed are mated.
281
Section C Animal Production
11011 The development of the Jamaica Hope dairy cow from Jersey cattle
and Zebu cattle is an example of upgrading to adapt a breed to suit the
conditions in the Caribbean.
11'012 A hybrid is the offspring produced by the cross-breeding of two different
breeds.
11013 Hybrid vigour is the increase in fitness shown in the hybrid as a result of
cross-breeding.
IR114 Disease-resistance in farm animals is important as it reduces the
dependence on the use of medicinal drugs, prevents the possibility of
drugs getting into human food and is less costly to the farmer. It also
prevents pathogenic organisms from becoming resistant to these drugs.
ITal 5 It is important to keep records of the performance of farm animals so that
good producers can be identified and also for the accuracy of the farm
accounts.
111116 Artificial insemination is the introduction of semen (collected from a male
animal with desired characteristics) into the reproductive tract of a female
animal on heat.
lY
IT017 Sugar, glycerol (to protect sperm during freezing), salts (to maintain
correct pH) and antibiotics are added to the semen.
11018 Two advantages of AI are: improvement of stocks; semen from
pedigree males can be used for many females; prevents injury to young
females; reduces venereal diseases; females do need to be transported
to breeding stations for servicing. Two disadvantages from: reduces
variation; expensive to set up; maintenance of storage facilities; failure of
conception.
r
ITQ19 The oestrous cycle is a sequence controlled by hormones in female
mammals and it extends from the beginning of one period of heat to the
beginning of another period of heat. During the cycle, ovulation occurs.
Oestrus, or heat, is the stage in the cycle when the female mammal is
receptive to the male.
104
Om%
11020 Ovulation is the release of an ovum from the ovary of a female.
11021 Three from: restless; swollen or reddened vulva; bellowing or mooing;
mucus discharge from the vulva; allows other cows to mount her; drop in
milk yield; loss of appetite.
ITQ22 The gestation period of a pig is 114 days on average (from 111 to 117
days).
11023 Colostrum is the first milk produced after birth and it contains antibodies
to protect the young from infection.
ITQ24 The parts of the oviduct of a hen are the infundibulum, the magnum,
isthmus, uterus or shell gland, the vagina and the vent (cloaca).
11025 Fertilisation takes place in the infundibulum.
ITQ26 The ideal nesting environment is cool, quiet, well-ventilated and
darkened.
11027 The humidity is maintained at 60% to prevent rapid loss of water by
evaporation, ensure normal embryo development and reduce mortality.
IT028 A donor female is made to superovulate so that more ova than normal
are released at ovulation. This means that (after fertilisation) there will be
more embryos to place in surrogate mothers.
11029 A catheter is introduced into the uterus via the vagina and the embryo is
inserted through the catheter.
ii
282
18 Animal genetics, breeding and reproduction
ITQ30 Three from: desirable characteristics introduced fairly rapidly; sex of
the embryos can be chosen; cheaper than importing a pedigree animal;
reduces transmission of diseases; makes use of non-pedigree females as
surrogates.
11031 The selected gene is inserted into the virus; embryos at the 4-8 cell stage
are infected with the virus; the selected gene is then incorporated into the
DNA of the cells of the embryo.
11032 A transgenic organism contains genes from another organism of a
different species.
Examination-style
questions
Multiple Choice Questions
1. Tamworth is the name of a breed of:
A dairy cattle
B goats
C pigs
D poultry
2. Which of the following is a breed of dairy cattle?
A Jamaica Hope
B Jamaica Red
C Jamaica Black
D Charolais
3. 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
4. In which part of the oviduct does the egg remain for the longest time?
A infundibulum
B magnum
C isthmus
D uterus
5. In a commercial incubator, how much space should be allowed for each
egg or chick that emerges?
A 15cm2
B 20 cm2
C 25 cm2
D 30 cm2
6. 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
7. (a) List FIVE classes of farm animals which are currently reared locally
and regionally.
(b) Name TWO breeds of any three classes of farm animals that you
have listed for (a).
283
Section C Animal Production
0-
8. (a)
(b)
What classes of farm animals have been developed in the Caribbean
region?
Complete the table listing breeds of farm animals and the Caribbean
country in which they have been developed:
Breeds of farm animals
9. (a)
(b)
(c)
(d)
10. (a)
(b)
(c)
11. (a)
(b)
j
12. (a)
(b)
13. (a)
(b)
(c)
14. (a)
(b)
15. (a)
(b)
284
Caribbean country where developed
Differentiate between: (i oestrus cycle, and
(ii) oestrus.
List the FOUR distinct phases of the oestrus cycle.
State the average length of the oestrus cycle in these female farm
animals:
(i) doe (goat)
(ii) sow
(iii) ewe.
Describe the oestrus cycle in the cow, stating the:
(i) length of the cycle
(ii) duration of heat or oestrus
(iii) time of ovulation.
List the common signs of heat in the cow.
Explain the relationship of the oestrus cycle, signs of heat and
pregnancy in farm animals.
State the importance of this relationship to the farmer.
List the essential steps in obtaining semen for artificial insemination.
State the main advantages and disadvantages of artificial
insemination.
What is the meaning of 'parturition'?
What assistance should the farm attendant provide to a sow at
parturition?
Describe the process of egg formation in poultry.
Describe the process of natural incubation.
How does artificial incubation differ from natural incubation?
Describe the process of embryo transfer in cattle.
Explain the advantages of embryo transfer.
Describe how genetically modified animals can be produced.
Discuss the advantages and disadvantages of the use of genetically
modified organisms in the production of food.
Mal husbandry
►,,i
By the end of
this chapter
you should be
able to:
3
/
/
3
3
3
3
3
3
3
3
3
Concept
m
ap
describe the care of young chicks and young rabbits
describe the rearing of broilers and layers
describe the rearing of rabbits
recognise the signs of general illness in farm animals
identify the pests and diseases of poultry and rabbits
recognise the symptoms of pests and diseases in poultry and rabbits
show how to prevent, control and cure pests and diseases in poultry
and rabbits
state why bees are of economic importance
recognise the different types of bee in a hive
describe the social behaviour of bees
understand the nature and control of diseases and pests of bees
describe how honey and other products of bees are harvested.
Animal husbandry
Importance of bees
Signs of illness
Management practices
Care of chicks
Pests and diseases
Types
brooding
poultry
queen
feeding
rabbits
worker
immunisation
munisation
Care of rabbits
Broilers and
layers
drone
Social
activities
Pests and
diseases
feeding
sanitation
Harvesting of
honey
cannibalism
285
I
Section C Animal Production
19.1 The care of young chicks and rabbits
In nature, female animals usually take care of their young until they are old
enough to fend for themselves. However, in livestock farming farmers take care of
the young animals, using recommended farming practices. This is carried out for
increased production and greater profits.
Some management practices are common to all farm animals, e.g. housing,
feeding, cleanliness and disease prevention. Other practices are specific to the
young of particular animals.
Brooding in poultry
brooding ► Brooding involves taking care of day-old chicks for 2 to 3 weeks. It takes place in
an enclosed area where they 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
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,
keeping 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 Figure 19.1 Natural brooding.
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
hen and chicks have sufficient feed and water at all times.
Artificial brooding
artificial brooding ►
F
141
k
286
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.
Before using a brooder, preparations should be made:
• the entire poultry pen should be cleaned and disinfected 2 to 3 days before the
chicks arrive
2
• the area needed for the brooder is calculated by allowing 225 cm per chick
(15 cm x 15 cm)
• the area is separated from the rest of the poultry pen with a movable partition
• the outer walls are screened with feed bags to keep out cold draughts of air
• litter (bagasse, wood shavings, straw) is put on the concrete floor to a
thickness of 5 to 7 cm; this absorbs droppings and keeps chicks off the cold
ground
• lighting and heating is set up over the centre of the brooding area: use an
infra-red 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 feeding so that chicks gain weight rapidly
• sheets of newspaper are spread over the litter for the introduction of feed to
the chicks on day 1 and day 2 of brooding
• two mini-waterers and two mini-feeders (trays) are put at opposite ends of the
brooder within the lighted area
19 • Animal husbandry
• a clip-board with a record sheet attached is placed at the entrance for poultry
record-keeping
• a foot-bath containing disinfectant is placed at the entrance: anyone entering
the poultry pen should disinfect their footwear to prevent infection with
disease-causing organisms.
lamp
litter
bucket for feed
cardboard surround
i
For how long are young chicks usually brooded?
In an artificial brooder, how much space should
be allowed for each chick?
i
What type of feed is used for the chicks?
1
Figure 19.2 A brooder and brooding equipment.
The brooding process begins when chicks are placed in the brooder and ends when
they are sufficiently feathered to cope with weather conditions. During this time,
the chicks are checked on a regular basis.
After brooding, they may be placed in other poultry pens or the movable
partitions can be shifted to allow access to more space (about 900 cm' per chick) in
the poultry house. Management practices are summarised in Table 19.1.
Management
practice
Cleanliness
Health
Feed
Water
Temperature
Procedure
• step into the foot-bath to clean footwear
• regularly replace newspaper soiled with droppings during the
first 2 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
• Marex: protects against Marek's disease; inject into the back of
the neck
• Newcastle disease/infectious bronchitis combined: one drop of
vaccine placed in one eye only
• fowl pox: vaccine inserted 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 on to the newspaper spread on the litter when
chicks are first placed in brooder
• add antibiotics and vitamins to 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 — pathogenic
protozoa)
• keep the initial temperature at 35°C; then reduce it by 2°C
each week until it reaches 24 to 26°C
• adjust the temperature by raising or lowering the lamp
• check chicks to see if they are too hot (chicks outside the
lighted area), too cold (chicks huddled under the lighted
area), or just ri ght (chicks dispersed under the lighted area)
Table 19.1 Management practices for the care of chicks.
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Section C Animal Production
debeaking
►
Chicks destined to 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.
Brooding in rabbits
kittens
►
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 to 10. Management practices are
summarised in Table 19.2.
Management Procedure
practice
Cleanliness
• remove and dispose of any dead kittens
• wash feeders and waterers daily
• incorporate droppings in deep litter beneath the hutch of the
doe
Feed
• provide a regular source of fresh feed (wilted herbage and
concentrates) for the doe
Water
• supply clean water regularly
..1101111k
Table 19.2 Management practices for the care of young rabbits.
What food is provided for the young rabbits when
they are 6 weeks old?
The kittens leave the nest box after 3 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.
19.2 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 light
and temperature conditions which promote growth. In the artificial incubation of
chicks, light conditions encourage feeding and the temperature is adjusted to the
stage of growth reached. 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
The cleanliness of housing and equipment ensures that risks of infection are reduced
and diseases are prevented. 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 rapidly. It is not necessary to provide feed and water for very
young rabbits as they suckle until they are 6 weeks old, but the does need clean
food and water every day for making milk to feed the young.
Adult rabbits are fed on wilted herbage and concentrates. They are excellent
converters of feed and can attain 1.8 kg in 8 weeks, with a feed conversion ratio
(FCR) of 3.5:1. The young are provided with herbage and concentrates just before
and after weaning.
Rearing poultry
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 6 weeks
288
19 - Animal husbandry
grower ration ►
laying ration ►
finisher ration ►
cannibalism ►
I
Explain why the temperature at which chicks are
brooded needs to be controlled.
Why should feed and water containers be cleaned
on a daily basis?
Practical activity:
Have a go at rearing rabbits and a
batch of broilers and layers. (This
activity was suggested in Chapter
16.) If this is not possible, visit
farms where chicks and rabbits
are being reared to observe the
management practices used.
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 life. Broilers are given finisher ration from 7 weeks until they
are culled at 9 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.
19.3 Rearing a batch of broilers
You will need to consider the following:
• location of housing for the poultry
• the size of housing, based on the numbers of chicks to be reared as broilers
• house construction: materials needed and their source; provision of water,
heating and lighting
• equipment required: feeders, waterers, cleaning equipment
• feed: the type needed; quantity required; storage facilities for the feed
• the chicks: source of day-old chicks
• immunisation, if it has not been carried out already
• record-keeping
• maintenance: organisation of checking, feeding and cleaning
• marketing the broilers at 9 weeks
• costs: a balance sheet of the inputs and the income.
There may already be a poultry pen available, but you must clean and disinfect it
and any equipment before use. Careful records of all costs will need to be kept:
the cost of feed, heating and lighting, the chicks, any medication needed, and
transport costs in obtaining the chicks or marketing the broilers.
19.4 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 signs of
ill-health in his stock. In addition, he should give first aid to animals as soon as
injuries and illnesses have been detected.
Healthy animals
Figure 19.3 A healthy farm animal.
Healthy animals have the following characteristics:
• alert and responsive to environmental stimuli
• the eyes are bright with no mucus on the sides or eyelids
• the coat is smooth, with a sheen; the skin is soft and pliable
• the appetite is good and the ration is eaten readily
• produce relatively firm faeces without straining
• the urine is not bloody or discoloured green
• bleat, grunt or moo normally and do not sound distressed
• do not limp when walking
• mix with the flock or herd and are not isolated
• have a normal rectal temperature for its class: poultry 41°C, goats and sheep
39.4°C, pigs 39.2°C, cattle 38.6°C.
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Section C Animal Production
Signs of illness
rrcu
■
Describe the condition of the coat in a healthy
animal.
What is the normal rectal temperature of sheep
and goats?
The general signs of illness in farm animals are:
• a dull, ruffled coat
• swellings or lesions on the skin
• dull, watery eyes with mucus on the sides and the eyelids
• listlessness and loss of appetite
• discoloured urine: reddish or greenish
• constipation or scouring (smelly, watery faeces)
• walks slowly, with discomfort, or lies down for long periods, lacking the
energy to stand up
• isolation from the flock or herd, being unable to keep up when grazing or
walking
• high rectal temperature, indicating a fever
• coughing, sneezing, noisy breathing sounds
• shivering or groaning with pain
• lack of alertness and failure to respond quickly to environmental stimuli.
In poultry, signs of ill-health include:
• loss of appetite
• respiratory problems
• general dullness and droopiness.
19.5 Pests and diseases of poultry and rabbits:
symptoms, prevention and control
Poultry
The major diseases of poultry (see Table 19.3) are Newcastle, fowl pox, Marek's,
coccidiosis, and pullorum. There is also concern about bird flu.
Disease
Newcastle disease:
caused by a virus;
affects poultry of all ages.
Fowl pox:
caused by a virus.
Marek's disease:
caused by a Herpes virus.
F
Coccidiosis: caused by a
protozoan.
Pullorum: caused by the
bacterium Salmonella
pullorum; mostly affects
young birds up to 3
weeks old; associated with
cannibalism.
290
Symptoms
Loss of appetite; droopiness; nasal
mucus discharge; twitching of head
and neck; breathing difficulties;
paralysis and sudden death; mortality
rate is high.
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.
Twisting of the neck and head (wry
neck); droopy wings; loss of weight;
grey colour of the iris; paralysis
followed by death; mortality rate is
high; disease can take several forms.
Droopiness and loss of appetite;
diarrhoea with blood in faeces;
vent becomes swollen and bloody;
mortality rate is moderate.
Loss of appetite; droopiness; white
diarrhoea; continual chirping;
mortality rate is high.
Prevention and control
There is no treatment for infected birds; young chicks
should be vaccinated; adopt sanitary measures by using
a foot-bath, cleaning and disinfecting poultry pens,
feeders and waterers; dead birds should be buried or
burnt.
There is no treatment for infected birds; young birds
should be vaccinated; all infected birds should be
isolated; carcasses should be buried or burnt.
There is no treatment for infected birds; day-old chicks
should be vaccinated; strict hygiene should be observed;
isolate infected birds and burn or bury carcasses;
resistant strains of poultry are available.
This can be treated with sulphur drugs and magnesium
sulphate in the drinking water; birds should be removed
from wet, infected litter; the 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 foot-baths and clean feeders
and waterers; litter should be stirred frequently to
absorb droppings; bacterium is destroyed by normal
disinfectants.
19 Animal husbandry
Disease
Symptoms
Prevention and control
Bird flu (avian influenza): Swelling of the head; blue
There is no cure, but good nutrition and antibiotics
caused by a virus,
colouration of the comb and wattles; may alleviate symptoms; vaccination not normally
loss of appetite; breathing problems;
recommended as vaccinated birds may remain carriers;
diarrhoea; drop in egg production;
infected birds should be isolated; sanitary methods
sudden death,
should be adopted; if outbreaks occur, birds are
slaughte red and carcasses burnt.
Table 19.3 Poultry diseases: their symptoms, prevention and control.
Rabbits
The major diseases (see Table 19.4) are snuffles, coccidiosis, mange, bloat and sore
hocks, but of these only the first three are of economic importance.
Disease
Snuffles: caused
by a bacteria]
infection,
Symptoms
Nasal discharge of mucus;
sneezing; rubbing of nose and
eyes with forepaws.
Coccidiosis:
caused by a
protozoan.
Mange: caused by
parasitic mites,
Loss of appetite; diarrhoea;
droopiness; loss of weight.
Head shaking, itching and
scratching; thick crusts of mites
accumulate inside the ear; loss
of fur; sores in the ears.
Prevention and control
Treated with sulphur drugs and antibiotics; isolate infected rabbits;
feed a nutritious diet and adopt sanitary measures; do not breed from
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 sulphur
drugs in the feed or added to drinking water.
Mineral oil can be massaged into the ear; clean infected areas with
antiseptic solution; apply lime/sulphur ointment; adopt strict sanitary
measures; clean and disinfect the rabbitry.
Table 19.4 Rabbit diseases: their symptoms, prevention and control.
Explain why ills important to isolate infected
animals once symptoms of disease are observed.
Describe the symptoms of fowl pox.
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 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.
19.6 The economic importance of bees
Which disease of rabbits is caused by mites?
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. Bee-keeping,
apiculture ► or apiculture as it is called, is a useful form of agriculture in developing countries. It
is not expensive or difficult to set up and hives can be constructed of local materials,
as described in Chapter 17.
In addition to making honey, bees are pollinators of crop plants. In commercial
apple production, many varieties are self-sterile and require cross-pollination 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
Why do apple trees need to be pollinated by
bees?
eyes and skin. It reduces inflammation and acts as a disinfectant.
291
Section C Animal Production
19.7 The types of bees in a hive
drone
In a honeybee colony, there are three types, or castes, of bee (see Table 19.5). Each
type is adapted to performing specific functions within the colony.
The three types are:
• the queens: fertile female bees; mate with drones (males); lay many eggs
which develop into new individuals; fertilised eggs develop into female bees
and unfertilised eggs develop into drones
• the workers: sterile (unfertile)female bees; carry out the duties around the
hive; act as nurses for developing bees; clean the hive; collect nectar and
pollen
• the drones: fertile male bees; mate with the queen.
worker
queen
Figure 19.4 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.
IT013
1
Which type of bee has no sting?
Queen
Fertile female.
Larger, longer body than
worker.
Shorter wings than
worker.
Sting with no barbs.
Poorly developed
mouthparts; fed by
orkers.
nction: lays eggs;
arms.
e-span: 5 to 6 years.
Drone
Fertile male.
Big, broad body.
Well-developed wings.
No sting.
Reduced mouthparts.
Function: to mate with
the queen.
Life-span: 4 to 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; collection of
honey and pollen.
Life-span: 4 to 5 weeks.
What are the functions of a queen bee?
19.8 The social activities of bees
The queen
royal jelly ►
The queen is responsible for laying eggs. After she has been fertilised by drones
on her nuptial flight, she can lay about 2000 eggs a day. Eggs are laid singly into
hexagonal (6-sided) wax cells on the combs in the brood box of a hive. Most eggs
develop into workers, some into drones and very few are destined to be queens.
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 only produced 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 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
292
19 • Animal husbandry
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
Describe what happens when bees swarm.
List the activities of the worker bees.
How is the social organisation of a bee colony
controlled?
I
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.
When workers are 2 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 3 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).
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.
19.9 Pests and diseases of bees
The main diseases of bees are:
• foulbrood: caused by a spore-forming bacterium
• acarine mite infestation
• dysentery
• varroasis: infestation by the parasitic mite Varroa.
These diseases are not widespread in the Caribbean. Therefore bee-keepers in the
region must take great care to keep their bees free from disease.
American foulbrood
American foulbrood ► American foulbrood is a highly infectious disease caused by the bacterium Bacillus
larvae. If bacterial spores get into young larvae, they germinate rapidly and kill the
larvae. The bacterium does not affect adult bees or older larvae. Spores are very
resistant to heat, cold and disinfectants. They remain viable for years in old combs,
in honey and on equipment.
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 which are added to the hive; but this does not kill the spores, it only
delays their growth.
The infection is spread by:
• feeding infected honey to young larvae
• use of second-hand equipment
• combs being moved from an infected hive to an uninfected one.
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.
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Section C Animal Production
Acarine mites
acarine mites ► Acarine mites are tiny arthropods (related to spiders) that get into the breathing
tubes of adult bees. The mites get into the young adult bees in the first week after
hatching, before they have left the hive, so the spread of the infestation depends on
the young bees being in contact with older, infested bees. Mites get into a colony
on the bodies of the workers or from a colony being moved into an infested hive.
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. During poor weather,
when bees are confined to the hive for longer periods, infestations may become
more serious and need treatment.
Treatment involves a smoke strip, which is lighted 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.
Dysentery
dysentery ►
Dysentery is suspected when the hive contents are soiled by the faeces of the bees.
This condition occurs mainly in countries where bees have a quiet period during
the winter and are confined to the hive. A build-up of faeces in the hive may
be caused by too much water in the food. Bees should only be fed 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 aggravate
other infections.
Varroasis
varroasis ►
Figure 19.5
Varroa mites clinging to
a bee larva.
Varroasis is caused by an infestation of larvae and adult bees by the parasitic mite,
Varroa. These mites feed on the body fluids of bees and can be seen as small brown
spots on the bee's thorax. The mites carry a virus which results in deformed wings
in adult bees. Severe infestations result in the death of whole colonies and beekeepers need to inspect hives regularly for signs of the mites. Mites may be present
in sealed brood cells.
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.
List THREE diseases that affect bees.
1
19.10 Honey and other bee products
1
Honey
How can mites be removed from a hive?
What causes foulbrood?
1
294
Honey is stored in the cells of the combs on the supers in a hive. When honey is
the right consistency, bees cap the cells with wax. Any uncapped cells are likely
to contain 'unripe' honey. The best way of removing honey 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.
The procedure involves the following steps:
• thorough cleaning of the spinner with boiling water
• drying the spinner
• removal of the wax capping of the cells on both sides of the comb: this is done
by running a sharp knife over the surface; wax is scraped on to a tray; if it is
19 Animal husbandry
heated, residual honey can be separated from the wax; the wax can be saved
and used later
• place uncapped frames into the spinner: most spinners will take up to four
frames
• extract the honey: start the spinner slowly, gradually working up to full speed;
after 2 minutes, reverse the frames and repeat the spinning; it takes 5 minutes
for the honey to be removed from the frames
• remove frames from the spinner: there will still be some honey left in the
frames but they can be replaced in the super and returned to the hive; the
bees will clean the frames.
Figure 19.7 Using a sharp knife
to remove the wax cappings from a
honey comb.
Describe how honey can be removed from a
comb by a spinner.
1/J
Why does the honey need to be filtered before it
is put into jars?
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 be cut out and sold as 'comb
honey', but this will also have pollen in it.
After honey has been extracted it will need bottling. If a clear honey is desired
it must be filtered, either through damp muslin or using 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 weight of honey.
Beeswax
Beeswax is secreted from wax glands on the underside of the abdomen on a worker
bee. The wax is used to construct cells in which eggs are laid and for storage of
honey and pollen. Bee-keepers can collect wax from the combs when honey is
extracted, but it has to be cleaned before use.
There are various methods of extraction, but the simplest 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 will melt and can be filtered and allowed to drip
into a container. This procedure should be watched; if the temperature gets too
high the wax could burn.
There are many uses of beeswax:
• making candles
• cosmetics
• crayons
• paints and varnishes
• coatings for washable wallpaper
• floor polish and car wax.
Medicinal products
propolis ►
pollen ►
Honey has been used to treat infections and reduce inflammation, but other
products from bee hives also have medicinal properties. Not all the claims made
for these are true, but they are used as 'natural' remedies and do work for some
people. None of the products will harm.
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 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 to the hive entrance a device which scrapes pollen from the legs of bees.
295
Section C Animal Production
Various claims have been made for the benefits of taking pollen, but it has been
royal jelly ►
Give FOUR uses of beeswax.
ITCl24
Explain why royal jelly is so expensive to buy.
Practical activities:
1. If possible, visit a bee-keeper
and observe the activity in
used to protect against hay fever.
Royal jelly is the milky liquid which 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 very expensive.
1
4111:1!V
•
•
the hives. Protective clothing
should be worn.
2. Collect pictures of the
•
•
equipment used in beekeeping and find out how much
honey is produced in your area.
Research the internet and
locate your local Bee-keepers'
•
•
Association. They will be able
to help you.
•
3. Visit local food stores and
pharmacies to find out if bee
•
products are available.
L
•
•
•
•
•
•
•
•
•
•
•
•
•
296
The brooding of chicks may be done naturally, using a broody hen, or artificially
using a brooder.
During brooding, chicks are housed, protected, fed and kept warm until they
are feathered and able to cope with prevailing weather conditions.
Similar conditions are provided for the brooding of young rabbits.
Farmers adopt management practices in the rearing of young chicks and young
rabbits. These include management of housing, feeding, sanitation and disease
prevention.
Animal health is important to the farmer and signs of good health should be
recognised.
The signs of ill-health in farm animals include a dull ruffled coat, listlessness
and loss of appetite, together with a high temperature, laboured breathing and
failure to keep up with the herd.
Major diseases of poultry include Newcastle disease, Marek's disease, fowl pox
and pullorum.
Methods for the prevention and control of poultry diseases include sanitation,
vaccination, isolation of infected animals and selection of disease-resistant
breeds.
The carcasses of dead birds should be buried or burnt.
In rabbits, the major diseases are mange, snuffles and coccidiosis.
Bee-keeping is easy to set up and provides an income for farmers.
There are three types of bees in a colony: queens, workers and drones. They
can be distinguished by their size, wings and functions.
The function of the queen is to lay eggs. She is the only fertile female in the
colony.
The function of the drones is to fertilise the queen. They are fertile males.
The workers are sterile females and carry out functions around the hive, feeding
larvae, cleaning and foraging for nectar and pollen.
The main diseases of bees are foulbrood, acarine mites, dysentery and varroasis.
Honey is extracted from the cells of combs in the hive, by spinning the combs
or scraping it out.
Honey is filtered to remove debris and pollen before being bottled. All honey
sold commercially has to be labelled with the producer's name.
Honey is the major product from keeping bees, but wax, propolis, pollen and
royal jelly can also be harvested and sold.
Wax can be collected and used to make candles, crayons, floor polish and car
wax.
Propolis, pollen and royal jelly are marketed for use in cosmetics and medicinal
remedies.
19 - Animal husbandry
1101 They are brooded for 21 days (3 weeks).
1102 225 cm 2 per chick.
1103 Broiler starter feed is used.
1104 Herbage (wilted) and starter ration is provided.
1105 The temperature is controlled so that chicks develop at a steady rate and
do not use up energy keeping warm. The growth rate is reduced if it is
too cold.
1106 Cleaning should be done to prevent infection and to remove any food
that might go bad.
1107 The coat should be smooth with a sheen and the skin soft and pliable.
1108 39.4°C.
1109 Isolation is needed to prevent the spread of infection to other animals in
the group.
It is also easier to treat an isolated animal.
11010 Fowl pox causes blotches and warts all over the body. Black scabs appear
on the comb, wattles and beak.
11011 Mange is caused by mites.
11012 Many varieties are self-sterile and need to be cross-pollinated with pollen
from a different variety before they will produce fruit. Bees carry out
cross-pollination as they gather nectar from the trees in a locality.
11013 A drone.
11014 The functions of the queen are to mate with drones and lay fertilised and
unfertilised eggs.
ITQ15 The queen, together with worker bees, will leave the colony and build
another nest (colony) in a new location.
11016 The activities of the worker bees are to look after and feed larvae, clean
the cells of the comb, make royal jelly, make wax, convert nectar into
honey, and forage for nectar and pollen.
11017 The queen secretes chemical substances called pheromones which spread
to the worker bees and control their activities.
11018 Three from: foulbrood, acarine mites, dysentery, varroasis.
11019 Mites can be removed by introducing into the hive substances which are
toxic to mites but not to the bees. Tobacco smoke has been effective in
removing mites.
11020 Foulbrood is caused by a spore-forming bacterium, Bacillus larvae.
11021 The cells have their wax caps removed and combs are placed in the
spinner. The spinner is set in motion, starting slowly and gradually
increasing speed. Combs are spun for 5 minutes, their position is reversed
and the procedure repeated.
IT022 The honey needs to be filtered to remove pollen and any debris from the
bees.
11023 Any four from: wax polish, car wax, crayons, candles, coatings for
wallpaper, paints and varnishes, cosmetics.
11024 Royal jelly is expensive because it only occurs in small quantities. It
is harvested from queen larvae cells and requires 100 cells to produce
about 25 g.
297
Section C Animal Production
Examination-style
questions
Multiple Choice Questions
1. In an artificial brooder, the space allowed per chick is:
A 220 cm2
B 225 cm2
C 230 cm2
D 235 cm2
2. Which of the following is NOT a sign of ill-health in animals?
A relatively firm faeces
B dull, watery eyes
C discoloured urine
D noisy, breathing sounds
3. Twisting of the head and neck in poultry is a symptom of:
A fowl pox
B coccidiosis
C Newcastle disease
D Marek's disease
4. Avian (bird) flu is caused by a:
A protozoan
B bacterium
C mite
D virus
5. A worker bee is a:
A fertile female
B fertile male
C sterile female
D sterile male
6. Which of the following activities of bees is NOT carried out by the
workers?
A laying eggs
B cleaning cells
C collecting nectar
D feeding larvae
7. 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
8. (a) (i) What is a brooder?
(ii) State the purpose of a brooder.
(b) List the steps for the preparation of a brooder.
(c) Describe the process of brooding chicks in a brooder.
9. (a) Name TWO major diseases of rabbits.
(b) Name the organisms responsible for these diseases and describe the
symptoms of these two diseases.
(c) What control measures would it be necessary to take if these diseases
occur in a rabbitry?
10. (a) (i) State the recommended methods of carcass (dead body)
disposal.
(ii) Why should carcasses of farm animals be disposed of in the
proper manner?
(b) (i) Explain the meaning of post-natal care.
(ii) State the importance of post-natal care.
298
19 - Animal husbands
11. Describe, using information from your own experience, how to raise
a batch of broilers. Your account should include the housing needed,
equipment required, source of the chicks, cost of feed and labour and
how they are marketed.
12. (a) Explain why bee-keeping is of economic importance.
(b) Describe how honey can be extracted from a comb.
(c) Name THREE other bee products that can be harvested from hives
and describe their uses.
13. (a) How does a drone differ from the other types of bee?
(b) Give an account of the activities of the worker bees in the hive.
(c) What happens during swarming?
14 (a) Name TWO diseases in bees that are caused by mites.
(b) For each disease, describe the symptoms and the measures needed to
control the disease.
15. Describe the structure and organisation of a honey bee colony. Include
reference to the different types of bees, their structure and functions.
29!
............
Td1 products tOC[1[10101B
By the end of
this chapter
you should be
able to:
3
3
3
3
3
3
3
li st products and by-products from farm animals
understand the importance of fish in human nutrition and livestock
feed
identify the different cuts of meat
describe the processing and preservation of milk
determine the dressing percentages of different farm animals
assess the most appropriate age to slaughter broilers
describe the process of marketing eggs and meat.
Concept map
Animal products technology
Marketing
Dressing percentage
Animal products
Weight and time to
slaughter
broilers
Eggs
Meat
cleaning
grading
grading
packaging
packaging
Milk
Eggs
-I
H
1
dried
fresh
as fertiliser
—
processing
fresh cuts
preservation
cured meats
cheese
yoghurt
300
Meat
Fish
as food for
humans
By-products
offal
manure
as food for
livestock
20 Animal products technology
20.1 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 20.1 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, both hatching eggs and table eggs are produced from layers, raised
intensively on farms or in open areas (free range) in rural communities.
Table eggs (for eating) are of two types:
• farm eggs or farm-fresh eggs: these have pale yellow yolks and are usually
cheaper
• common fowl eggs: these have orange yolks, are popular and more expensive.
hatching eggs ►
What is the difference between eggs for hatching
and table eggs?
^r
Hatching eggs are used by poultry farmers. Either these eggs are incubated and
then sold as day-old chicks to be raised as layers or broilers, or poultry farmers will
purchase fertile eggs to incubate, raise the chicks and replenish their stock.
By-products from eggs include:
• 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
• egg-shells: composed of 95% calcium carbonate; can be ground to a powder
and used in animal feed as a source of calcium; artistic uses include painting.
Milk
How is milk pasteurised?
Explain what is meant by the initials UHT.
List FOUR dai ry products which can be made on
the farm.
homogenisation ►
pasteurisation ►
sterilisation ►
Practical activity:
Visit a milk processing facility in
your locality. Alternatively, visit a
dairy farmer and find out what
happens to milk that is produced
Does the farmer use the milk to
make products on the farm?
Milk is important in human nutrition and much 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 major processes involved in milk treatment are:
• examination: to determine bacterial content, butterfat content, unusual
odours and foreign matter; examination is important for grading milk
• removal of foreign matter, such as dirt particles: this is done using a machine
called a clarifier, by centrifugal force
• separation of butterfat: produces low-fat and skimmed milk; other low-fat
products can be made using the milk
• homogenisation: butterfat globules are broken up into minute particles; milk is
heated to 72°C for 15 to 20 seconds to pasteurise it; then it is subjected to high
pressure and forced through a valve; cream formation on the surface is prevented
• pasteurisation: destroys pathogenic organisms, thus safeguarding public
health; prolongs the storage of milk; maintains the nutritional value, taste and
colour; achieved by heating to 63°C for 30 minutes or to 72°C for 15 to 20
seconds; milk is then rapidly cooled to about 3°C
• sterilisation: used in production of UHT (ultra-high temperature) milk; milk
is heated to 140°C for 3 to 5 seconds; this destroys all micro-organisms; taste,
colour and nutritional value are maintained; this considerably extends the
storage life of milk
• packaging: glass bottles, paper cartons or tetrapacks can be used; these are
sealed automatically and aseptically; they are placed in boxes and stored at
cool temperatures.
Packaged milk should be stored in a cool place at 4°C. Milk is transported in
refrigerated delivery trucks to supermarkets and consumer outlets.
Milk is used to make other dairy products either on the farm or in processing
plants. Those 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.
301
Section C Animal Production
Honey
Honey and other products from bees have been described in Chapter 19.
Fish
Fish and shell-fish are of importance as food for humans. They are rich sources of
protein, vitamins (A, D, B vitamins — thiamine, riboflavin and niacin) and minerals
(iodine, calcium and phosphorus). Fish provides an alternative to meat and is
more easily digested than many forms of meat. It can be used in a variety of ways,
including freshly-cooked, baked, curried, stewed, fried, grilled and steamed. Some
fish and shell-fish, such as sushi and oysters, are eaten raw. Fish can be preserved
by freezing, smoking, salting, drying and canning.
Fish is also used as a feed supplement for livestock. The bones of fish are ground
up and made into bone meal. Fishmeal is made by drying and grinding fish waste
or unwanted fish. Ground oyster shells are fed to laying hens, providing calcium
for shell formation.
Figure 20.2 Tilapia is a fish which is
farmed in the Caribbean.
Meat
Meat is an important source of protein in the diet. We eat meat from:
• poultry: chicken and duck
• goats
• sheep: mutton and lamb
• pigs: pork and bacon
• cattle: beef
• rabbits.
Explain why fish is an important food for humans.
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 are reared without growth
stimulants or chemicals in their feed.
dressed carcass ►
Name FOUR cuts of lamb.
1
From which animal do spareribs come?
carcass quality ►
ITQ8
List FOUR fresh meat products which are not
major cuts.
Practical activitiy:
Visit a meat processing facility
to identify different cuts of meat
and carcass quality. Alternatively
you could use pictures to help you
identify the cuts.
302
The carcass of a slaughtered animal is usually treated to produce a dressed carcass
(the entrails and head are removed).
The dressed carcasses of farm animals are usually cut into sections, each having a
special name. The cuts have varying shapes, and are differently graded for specific
purposes, such as roasting, grilling, braising or for the barbeque. They are graded
and priced to suit the tastes, preferences and affordability of consumers. The major
meat cuts are illustrated in Figures 20.3-20.6.
The carcass quality refers to these characteristics of the carcass:
• its conformation: proportion of meat and fat to bone; meatiness; shape
• colour: beef should be bright red; veal is white or light pink; pork is greyish-pink
or darker; lamb is light to dark pink; chicken is pinkish white; duck is reddish
white
• texture: whether it is soft, moist and firm rather than tough, stringy and dry
• fat: quantity; colour (firm and white in pork; white, smooth and even in lamb;
creamy white in beef; whitish yellow in poultry); marbling (fat between and
around the muscle fibres)
• palatability: aroma; tenderness; juiciness; flavour.
Apart from the major cuts described above, 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, such as bologna and salami.
20 - Animal products technology
Boston
butt
spare '
bacon
jowl
/ picnic .---
hind feet (pig's feet)
Figure 20.4 Meat cuts of lamb.
Figure 20.3 Meat cuts of pig.
neck
chuck
nb
sirloin
rump
rib
bladpp ,' plate
_
\
\!\
Figure 20.5 Meat cuts of poultry.
- — brisket
shank
-
topside
IF
--f
flank
'\
knuckle
outside
- shank
Figure 20.6 Meat cuts of beef.
Offal and other by-products
offal ►
What is meant by offal?
r =
Give THREE uses of the inedible parts of farm
animals.
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. For example, black pudding is
made from blood, tripe is prepared from part of a cow's stomach, and many dishes
contain chicken livers. Offal and meat scraps are made into pet food.
Other parts of farm animals can be put to good use. The skins are made into
leather, bones into bone meal and hoofs and horns into fertiliser. Fat is rendered
down and used to make lard and soap.
303
. 7
Section C Animal Production
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 which 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.
carbon dioxide
released to the
atmosphere
carbon dioxide
absorbed by
plants through
photosynthesis
anaerobic
decomposition
releases methane
Figure 20.7 A biogas generator — manure has the potential to generate much
energy.
20.2 The dressing percentage of farm animals
live weight ►
dressed weight ►
dressed carcass weight ►
dressing percentage ►
Live weight is the weight of an animal before slaughter. Live weight in cattle and
small ruminants is often referred to as '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 offal has been removed.
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 animals and are of economic importance to producers and consumers.
Dressing percentage (see Table 20.1) refers to the percentage of the live weight
usually obtained as edible carcass (meat) after slaughter. The formula for calculating
the dressing percentage is as follows:
Dressing percentage =
Dressed weight (kg)
100
Live weight (kg)
1
For example, if the live weight is 115 kg and dressed weight is 85 kg,
85 kg
100
00
then the dressing percentage =
x
115 kg
= 73.9%
Define carcass weight.
What is meant by the dressing percentage and
how is it calculated?
Class of farm animal
Poultry
Rabbits
Dressing percentage
75-80
55-65
Goats and sheep
55-60
Pigs
70-75
Cattle
50-69
Table 20.1 The dressing percentages of major farm animals.
304
20 - Animal products technology
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 that the feed conversion ratio (FCR) drops
significantly.
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 animals.
20.3 The slaughter of broilers
The time for slaughter can be determined by their dressing percentage and their
age. At about 9 weeks a broiler will weigh 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 6 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 9 weeks old, but faster-growing breeds may reach the required weight
earlier, at 7 weeks.
If the number of broilers is small, they can be slaughtered by hand. However,
with larger numbers slaughtering is usually mechanised and a production line is
set up. Whichever method is used, birds are not given food for 6 to 8 hours but are
allowed water.
Practical activity:
Calculate the live dressed weight
of the broilers mentioned.
Which parts of the intestines are saved and
cleaned for use?
Explain why a broiler is scalded after slaughter.
-- ,- _
Practical activities:
1. Slaughter and dress some
broilers for market. This could
be a follow-up to the raising of
a batch of broilers suggested
in an earlier chapter. If this is
not possible, observe broilers
being dressed and prepared for
market by visiting a local farm
or a large poultry producer.
2. Investigate marketing
strategies for selling broilers.
Check out local stores and
supermarkets to find out how
they sell their chickens.
Using humane methods
I
The most humane method is to cut the jugular vein in the neck with a very sharp
knife. Blood drains out for 2 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 1 minute. This makes the feathers easier to remove and feathers
should be taken off 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 internal organs, the head, neck and feet.
After removal of the head and neck, internal organs in the upper part of the body
cavity can be loosened.
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, liver and gizzard (stomach) are separated from the rest of the intestines
and cleaned. The heart is washed to remove any blood, the gall bladder is removed
from the liver, and the gizzard is opened to remove any contents and its lining
removed. These parts are referred to as the giblets and are often sold with the
bird. Chicken livers are used to make pate (pie) and other dishes. Whole birds are
packed into polythene bags and sent for sale or frozen.
305
Section C Animal Production
20.4 The marketing of eggs and meat
Eggs
Describe how eggs are cleaned.
How are eggs packed in the egg crates?
Practical activity:
Collect, clean, grade and pack
eggs.
Eggs are fragile so care needs to be taken when handling them. Firstly, eggs are
collected from nest boxes and battery cages by lifting each egg carefully and placing
it in an egg basket. Care should be taken to prevent eggs from rolling, colliding and
cracking. The number collected is recorded each day.
Eggs are then cleaned by wiping with a clean piece of cloth which 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 injury. 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 avbids 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 to 13°C.
Eggs are supplied wholesale to supermarkets and middlemen for pricing,
labelling and retailing to consumers.
Meat
abattoir ►
Figure 20.8 Some packaged poultry.
vacuum packaging ►
306
The marketing of meat follows slaughter of animals at the appropriate age or
weight. Slaughter of sheep, goats, pigs and cattle is usually carried out in an
abattoir or slaughter house. 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, 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 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.
After ageing, the carcasses are cut into the joints and cuts described on page 303.
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 for the convenience of the
consumer.
Packaging needs to allow the passage of gases but at the same time reduce the
loss of water. To achieve this, plastic films control 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 purchasing.
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 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.
20 - Animal products technology
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
Explain why meat is left to age before being sold
for consumption.
How is the bright red colour of meat retained
when it is packaged?
process.
Many products from farm animals are used for human nutrition and a number
of by-products have economic uses.
• Eggs are produced in large numbers and are nutritious as they contain protein,
fats, vitamins and minerals.
• Hatching eggs and table eggs are produced by layers.
• Hatching eggs are fertile and incubated to provide day-old chicks for sale to
poultry farmers.
• By-products from eggs include dried eggs for cooking and the food industry,
and egg-shells used in animal feeds as a source of calcium.
• Milk is important in human nutrition but is perishable and needs treatment to
keep it fresh and palatable for the consumer.
• Butterfat is removed and milk is homogenised, pasteurised and packaged before
it is supplied to consumers.
• Pasteurisation ensures that pathogenic micro-organisms are killed and enables
milk to be kept longer.
• Milk can be sterilised by heating to a very high temperature (UHT milk) and
this enables it to be kept for long periods.
• Milk by-products include yoghurt, cheese, butter and ice cream.
• Milk can be processed to produce powdered milk and condensed milk.
• Fish is an important source of protein and an alternative to meat. Fish is used
in the preparation of feed supplements for livestock.
• Meat is an important source of protein in the diet of non-vegetarians.
• The dressed carcasses of farm animals are cut into sections, each with a special
name.
Cuts may be divided into steaks or chops, minced or made into sausages and
other meat products.
• Offal is those parts of a slaughtered animal that are used for food but do not
consist of bone or skeletal muscle.
• Live weight and dressed weight (carcass weight) vary but are related to the
dressing percentage of the slaughtered animal.
• Age and weight are used to determine when farm animals should be slaughtered.
• Animals to be slaughtered should be treated gently and humanely.
• The time for the slaughter of broilers is determined by their age and dressing
percentage.
Slaughtering can be done by hand or mechanically on a moving line.
• After slaughtering, birds must be scalded before feathers are removed.
The carcasses are dressed by removing the head, feet and intestines.
• Before marketing eggs, they should be cleaned, graded and packed into egg
crates.
• After slaughter, carcasses are left to age and develop flavour. This improves the
quality of meat.
• Meat may be placed in packaging which allows the passage of gases but prevents
the loss of water. This keeps the meat fresh and maintains its red colour.
• Some meat and meat products are vacuum packed to exclude all air.
•
307
Section C Animal Production
1111
Eggs for hatching should be fertile, table eggs are not.
MR Either the milk is heated to 72°C for 15 to 20 seconds or to 63°C for 30
minutes.
11- 03 UHT means ultra high temperature and refers to milk being heated to
140°C for 3 seconds.
ITN Four from: butter, cottage cheese, yoghurt, ghee, ice cream.
ITQ5 Fish is an important source of protein, it is an alternative to meat and it is
easily digested. For some communities it is the main source of food.
1106 Four from: shoulder, neck, ribs, loin, sirloin, leg, fore shank, hind shank,
breast.
ITQ7
Spareribs come from the pig.
IT08 Four from: chops, steaks, minced meat, sausages and roasts.
ITQ9 Offal is those parts which are used as food but do not consist of bone or
skeletal muscle. Liver, kidneys, heart, tongue and trotters are examples.
11111 0 Three from: skins made into leather; bones and hoofs used as fertiliser; fat
used to make soap; dung used to generate biogas.
IT011 Carcass weight is the weight of the meat after the animal has been
slaughtered and the offal removed.
11012 Dressing percentage is the percentage of the live weight usually obtained
as edible meat after the animal has been slaughtered. It is calculated by
dividing the carcass weight (dressed weight) by the live weight in kg and
multiplying by 100.
IT013 Scalding takes place to make the feathers easier to remove.
11014 The heart, liver and gizzard (stomach) are saved, cleaned and used.
11015 Eggs are cleaned by wiping with a damp, clean cloth.
11016 Eggs are packed in crates with large ends uppermost to avoid pressure on
the thin membranes and prevent damage to the air space.
ITQ17 Meat is left to age to develop tenderness and flavour.
11018 The bright red colour of meat is maintained by the inclusion of oxygen
within the packaging.
Examination-style
questions
308
Multiple Choice Questions
1. Milk is homogenised to:
A retain its flavour
B destroy pathogenic organisms
C remove dust and particles
D break up fat globules
2. 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
3. Fish is a rich source of:
A iodine
B magnesium
C potassium
D iron
20 • Animal products technology
4. Brisket is a cut of meat from:
A pigs
B sheep
C cattle
D goats
5. 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: (i) hatching eggs, and (ii) 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) Describe the steps involved in milk processing and preservation.
8. (a) Explain why milk, as a perishable product, requires special
treatment.
(b) List and describe the processes involved in milk treatment.
9. (a) Explain the meaning and relationship of: liveweight, dressed weight
and dressing percentage.
(b) (i) Write down the formula, and then calculate the dressing
percentage of a pig which had a liveweight of 114 kg and a
dressed weight of 82kg.
(ii) State the importance of liveweight and dressed weight to the
consumer.
10. (a) List TWO criteria which are generally used in deciding when to
slaughter farm animals.
(b) Complete the table, stating the age or the optimal liveweight at
which farm animals should be slaughtered.
Class of animal
Age
Poultry (chickens)
Rabbits
Sheep
Pigs
8-9 weeks
Optimal liveweight for
slaughter
2.0-3.0 kg
10-12 months
90-100 kg
Explain why it is uneconomical for a farmer to rear meat animals
beyond a certain age.
11. Describe the processes involved in the slaughter and dressing of broilers.
(c)
..........
(use
■„
By the end of
this chapter
you should be
able to:
3
3
3
3
3
3
explain what is meant by horticulture
understand the importance of horticultural plants
describe the management practices used in the cultivation of some
types of horticultural plants
explain the harvesting techniques used
describe the quality requirements for flower production
describe the establishment and maintenance of lawn and turf grasses.
Horticulture
Botanic
gardens
Horticultural
societies
Horticultural
plants
Management
practices
Lawn
establishment
nutritional
propagation
Mowing
aesthetic
environmental
requirements
Types of grass
medicinal/
therapeutic
seeding
pest and
disease control
sods
religious
harvesting
shading
marketing
sprigs
plugs
handicraft
utilisation
Management
fertilising
pests and
diseases
watering
310
21 - Horticulture
21.1 What is meant by horticulture?
ho rticulture ► Horticulture refers to the small scale cultivation of crops. Horticulture differs from
ag ri culture in the following ways:
• small plots of mixed crops are grown rather than large fields of one crop
• a wider variety of crops is grown, often mixing tree crops and ground crops
• ornamental crops may be cultivated as well as edible ones.
ornamentals ►
Many techniques used in preparation of the ground, planting of seeds and
propagation of plants are the same as in agriculture.
Ho rt iculture can be divided into two sections: the cultivation of edible plants and
the cultivation of ornamentals (attractive plants, especially flowers).
Ho rt iculturalists may specialise in:
• planting, cultivating and marketing trees and other woody perennials
(arbo ri culture)
• cultivating and marketing flowers (floriculture)
• cultivating and marketing vegetables and fruit
• cultivating and marketing landscape plants (landscape gardeners).
Courses in horticulture
Courses in horticulture are taught in universities and colleges. These offer training
in the cultivation of plants and the management of horticultural businesses.
Degrees in horticulture are taught at the St Augustine Campus of the University of
the West Indies, Trinidad and Tobago.
Within universities, research may be carried out into crop production, plant
propagation, plant breeding and biotechnology (genetic enginee ri ng).
Botanic gardens
botanic gardens ►
Explain how ho rticulture differs from agriculture.
Many Caribbean islands have botanic gardens, where there are collections of
plants representative of the locality and region. Some, such as Bath Gardens and
Castleton Botanic Gardens in Jamaica, were originally used for the propagation
of plants for the plantations, but have now been turned into parks and tourist
attractions.
r^
What name is given to the cultivation and
marketing of flowe rs?
Practical activities:
1. If possible, visit a local botanic
garden or horticultural station.
Note the variety of plants. Are
they just from your island or
are they representative of the
whole Caribbean region?
2. Find out if there is a local
horticultural society. If so,
investigate their programme of
events.
Figure 21.1 A botanic garden in the Caribbean.
ho rt icultural societies ► There are also horticultural societies, organising flower shows, exhibitions, lectures
and visits, in many areas. Some have an international reputation and exhibit at
events in Europe, such as the Chelsea Flower Show in the UK.
311
Section D: Horticulture
21.2 The importance of horticultural plants
Many plants cultivated in the Caribbean are of economic importance, mainly the
provision of food for humans and animals (see Table 21.1). But plants are also
grown for medicinal, therapeutic and recreational purposes. The cultivation of
plants provides employment and income for the producers.
Many plants are native to the Caribbean, but others were brought from other
countries by settlers. Brassicas, beans and salads have been introduced as naturally
occurring food plants are few. Examples of native plants which provide food are
pawpaw, peppers and star apple.
Use
Nutritional
Aesthetic
Medicinal
and
therapeutic
Religious
Shading
Name TWO herbs that are cultivated for medicinal
purposes.
Handicraft
Importance
Any plant that produces a
food crop for humans and
animals.
Ornamental plants
providing pleasure and
decoration.
Many native plants have
been used for medicinal
purposes in the past and
some are still cultivated by
herbalists.
Many religious practices
involve the use of herbs
for healing.
The provision of areas
shaded from the sun
is needed for livestock
on farms; also useful
in gardens, parks and
recreational areas.
Plants that provide
materials for making
furniture and craft objects.
ri w
Examples
Vegetables (beans, maize, tomatoes),
fruit trees (apples, citrus, peaches),
grasses (for hay, silage).
Flower crops such as poinsettia,
heliconia; ornamental trees for parks
and gardens.
Chenopodium ambrosioides ( Mexican
tea) used for gastric upsets and to get
rid of intestinal worms; Capsicum spp.
(peppers) with a variety of uses; Aloe
vera produces a healing balm.
Aloe vera has already been mentioned,
together with many others; perhaps
not so much used in present times.
Any trees; on farms the trees can be
citrus or other fruit-bearing species,
providing additional income; native
species in parks and botanical gardens.
Wood from trees; Talipariti elatum
(blue mahoe) is a tree that provides
timber for cabinet-making and other
decorative objects.
Why are plants grown to provide shade on farms1
".1
21.3 The cultivation of horticultural plants
Citrus (Citrus genus)
Varieties: grapefruit (White Marsh, Ruby, Foster); orange (Valencia, Navel); lime
( West Indian, Tahiti); mandarin; lemon; tangerine; citron.
• Propagation: by budding; planting out when 1 year old.
• Planting: well-prepared soil; planting holes 45 cm long x 45 cm wide x 45 cm
deep; use pen manure; place plant in centre and form a mound of soil around
the plant.
• Pest and weed control: weeds controlled by brushcutting, herbicides (Karmex,
Gramoxone) or use of cover crop (kudzu); leaf-cutting ants, aphids and black
bees controlled by appropriate pesticides; fungicides protect against scab and
withertip; use disease-resistant rootstock to avoid tristeza, a viral disease.
• Harvesting: trees come into full-bearing in 3 years; sun-ripened fruits are
picked manually; collected in crates.
• Post-harvest handling: fruits delivered to depots for sorting, grading and
weighing; stored in a cool area before being transported to wholesalers and
retailers for local consumption or to a citrus processing plant.
312
21 • Horticulture
Name THREE insect pests of citrus crops.
Describe how citrus trees are propagated.
Figure 21.2 A mango tree bearing
fruit.
Describe the post-harvest treatment of mangoes.
r:
Explain why mango trees are used for shade and
shelter.
Uses: good source of vitamin C and minerals; fresh fruit for local consumption;
used to produce fruit juices, bottled, canned or packed in cartons; fruit sections
canned; citrus pulp is fed to livestock.
(See page 81 for a picture of a citrus tree.)
Mango (Mangifera indica)
Varieties: Tommy Atkins, Madame Francis, Champagne, Julie.
• Propagation: can be grown from seed; seedlings raised in a shaded nursery; if
specific varieties required, these can be grafted on to healthy rootstocks during
the first year of growth
• Planting: grow on a wide variety of soils, but best in full sun on light,
well-drained soils; drought-tolerant; plant out seedlings 1 to 2 years after
germination; protect young trees from grazing animals; often planted as shade
trees as they have a dense canopy and animals can shelter beneath them.
• Pest and weed control: susceptible to scale insects, tip borers, fruit flies, seed
weevils and mites; treatment with insecticides if needed; wet and humid
conditions during flowering and fruiting cause outbreaks of fungal diseases,
such as anthracnose and mango scab — treat with fungicide; bacterial black
spot is treated with a bactericide
• Pruning: prune every 1-2 years to reduce canopy and to remove dead
branches from within the crown.
• Harvesting: trees bear fruit 2-4 years after field planting; fruit take 3-6 months
to ripen; ripe fruits picked by hand and placed in crates.
• Post-harvest handling: fruits are dipped in hot water and fungicide to reduce
fruit rot during storage; fruits are graded and packed into crates; stored at a
cool temperature.
Uses: contain sugars, vitamins, minerals and fibre; eaten fresh and in desserts; can
be processed into drinks, juices and used in a variety of dishes; unripe mangoes are
used to make pickles and chutneys.
The trees provide shade and shelter for livestock.
Avocado (Persea americana)
Varieties: Hass, Pollock, Fuerte, Lula and various hybrids.
• Propagation: can be grown from seed but have a period of 4-6 years before
they bear fruit; so mostly propagated by grafting; rootstocks can be propagated
by seed or by layering; year-old scions are grafted on to rootstocks and left for
6-12 months before planting out; grafting is the usual method of propagation
to maintain quality and yield of fruit.
• Planting: soils need to be well-aerated; thrive in loose sandy loam; young
plants need room for good root growth.
• Fertilisers: young trees should be treated every 3 months with a general
fertiliser, after the first year of growth; older trees benefit from a nitrogenous
fertiliser applied twice a year.
• Pest and weed control: use tin trunk wraps to protect the fruit from rats and
squirrels; control the six-spotted mite with a miticide; Dothiorella canker
(causes dark spots on the flesh) and root rot are fungal diseases which damage
the crop; use disease-free certified plants; if tree is infected, there is not much
that can be done; avoid planting in areas that have had diseased trees; use
virus-free stock for propagation.
• Pruning: usually no need for pruning.
• Harvesting: time of harvest depends on the variety; some varieties ripen 6-8
months after flowering; others require 12-18 months; fruits may get bigger
after maturity if left on the tree; fruits are picked hard and green but must be
313
Section D: Horticulture
mature if they are to ripen; avocados are biennial bearing (heavy crop one
year followed by a light crop the following year).
• Post-harvest handling: fruit is kept cool after harvest but will ripen in a few
days at room temperature; in retailing outlets, fruit is kept cool until needed;
some varieties can be picked when mature and kept cool for up to 6 weeks.
Explain why avocados are usually propagated by
grafting.
Describe the harvesting and post-harvest
treatment of avocados.
1
Uses: rich in fibre and polyunsaturated vegetable oils; eaten as a vegetable; used in
salads and guacamole.
Banana (Musa genus)
Varieties: Dwarf Cavendish, Gros Michel, Lacatan, Robusta, Valerie;
plantain: French, Horse, Dwarf
Local selections: Silk Fig, Sucreir, Moko, Burro.
• Propagation: suckers, preferably sword suckers; bull-heads and maiden
suckers.
• Planting: soil with medium tilth; dip suckers into insecticide/fungicide mixture;
place 30 g NPK (22:11:11) in the planting hole; plant suckers 2 m apart with
3 m between rows.
• Pest and weed control: brush weeds using a weed-wacker; use Gramoxone to
control weeds between rows; control banana borer with insecticide/fungicide
mixture; caterpillars and leaf-eating pests controlled with Pestac or Rogor;
nematodes controlled using Nemagon and Furadan applied to soil; banana
leaf spot is avoided by using resistant varieties such as Valerie, Lacatan and
Robusta.
• Cultural practices: dry leaves and suckers should be pruned every 4-6 weeks,
ensuring that each stool contains one 'mother' plant and one follower;
pruning helps to control fungal diseases; it also improves fruit quality (size
and thickness) and yield; after each bunch is formed, remove the flower
cushion and place a polythene bag around fruits to protect them from injury
('sleeving').
• Harvesting: when 'three-quarters full' for export and at 'full' stage for local
consumption; use a cutlass or machete to partially cut the banana trunk so
that it bends over, bringing the bunch within reach; cut off a bunch and avoid
damaging or bruising the fruits.
• Post-harvest handling: de-hand bunches carefully using a sharp knife; wash
off latex and dip in fungicidal solution to prevent stem rot; air dry the fruits;
pack in cardboard boxes for export or store in a dry, warm area for ripening;
fruits are graded according to variety, quality and condition for wholesaling,
retailing and profitability.
Figure 21.3 Sleeving.
How are bananas propagated?
rruic
What is meant by 'sleeving' and why is it done?
1
Uses: consist mainly of carbohydrates, vitamins and minerals; consumed as fresh
fruits and desserts; immature fruits are boiled and made into soups, broths and
pies; reject fruit and chopped green leaves can be fed to pigs and ruminants.
Miniature golden apple (Spondias cytherea)
(also known as June Plum, pommecythere)
• Propagation: scions from tall golden apple trees are grafted on to dwarf
rootstocks; this ensures large fruit size; the scions should be free from disease.
• Planting: grafted plants are put into the ground at 10-15 m apart; usually
grown as isolated trees or small groups.
• Pest and weed control: trees are susceptible to mealy bug and fruit flies;
controlled by the use of insecticides.
• Cultural practices: the low height of the trees is maintained by removing the
top branches when trees reach 6 years old; repeat the pruning every 6 years.
Figure 21.4 A golden apple tree.
314
21 • Horticut
• Harvesting and post-harvest handling: trees produce fruit 3-4 years after
planting; fruit is picked manually; needs to be handled carefully to prevent
bruising; placed into crates; transferred to cool storage area before transport
to wholesaler, retailer or processing plant.
ed;
;ed in
What are the advantages of using a dwarf
rootstock for the propagation of golden apples?
Uses: contains sugars, vitamins and minerals; ripe and unripe fruits are eaten r
can be stewed with ginger and sugar; made into chow; juiced; made into jam.
Ornamentals
ilerie;
xture;
pith
to to
tide
vks,
ury
ivoid
rig;
1g,
fresh
s and
ase
he
rrs.
Heliconias, orchids, ginger lilies, anthuriums and roses are cultivated in
Caribbean. Most are marketed locally but some are exported.
Varieties
• Heliconias: belong to the banana family and are referred to as 'wild banana!
Golden Torch, Bird of Paradise, Lobster Claw.
• Orchids: popular as cut flowers.
• Ginger lilies: red, pink and white varieties.
• Anthuriums: local selections include pink, white and salmon hybrids
(Trinidad, Calypso); Dutch cultivars include Anneke 141 (pink), Nette 123
(orange), Jose and Cuba (white); Hawaiian cultivars include Ozaki, Manao
Mist and Obake.
• Roses.
Cultivation
The land is prepared by clearing, ploughing and rotavating to a medium ti
Pen manure is spread and incorporated into the soil and raised cambered b
are formed, making sure that drainage is adequate. Proper field drainage help
control root rot and stem rot.
Pruning of old leaves and stems that have borne flowers should be done regula
Clumps of plants that have become too clustered can be thinned by pruning or
out and then transplanted into new plots. Anthurium leaves need to be thin
leaving four leaves per plant, to allow air circulation and for disease control.
Anthuriums and orchids need the correct light intensity and humidity.
cropping area should be shaded with saran shading, supported by posts, to a he
of 2.5-3 m. Crops need to be watered regularly. Misting systems may be insta
for orchids so that the plants can be misted twice daily. Roses need protection 5
the sun, and are often given a resting period, between September and Febru
when leaves are removed and the bushes pruned.
Propagation
• For heliconia: offshoots or rhizomes divided into clumps (2 to 3 shoots) or
setts (10-15 cm).
• For ginger lily: offshoots or rhizomes as above, or plantlets from old bloom!
propagated in individual containers each with 2-3 plantlets.
• For anthurium: offshoots or suckers from the mother plant; rooted tops of
plants (cuttings); plantlets propagated by tissue culture; seedlings (hybrids)
propagated in a nursery.
• For orchids: plantlets; offshoots.
• For roses: cuttings.
Fertilisers
NPI{ fertilisers are used at intervals, usually 3 weeks after planting and the
2-monthly intervals. High phosphate fertilisers are applied initially, followe
ones with higher nitrate and potash content. Heliconias and ginger lilies be
from pen compost every 4-6 months.
Section D: Horticulture
Weeds and pests
Weeds can be controlled by hand-weeding and by applying Gramoxone, shielding
How are ornamentals propagated?
Practical activities:
the plants. Heavy mulching of anthuriums with semi-rotted bagasse or coconut
husks will help to smother weeds.
Insect pests, such as caterpillars, aphids, mealy bugs, beetles and thrips, can
be controlled by using insecticides such as Rogor, alternating this with Pestac or
Dipterex. Leaf spot diseases are controlled by Cupravit. Anthuriums, roses and
orchids are prone to fungal diseases on their leaves, stems and flowers.
1. Grow a citrus, mango, avocado,
Time taken for flowers to form
List THREE uses of ornamentals.
1
banana or miniature golden
apple plant from a seedling and
maintain it.
2. Cultivate TWO ornamental
plants.
3. Find out as much as you can
(using books, fact sheets
and the internet) about ONE
horticultural plant and produce
a written, illustrated report on
that plant. Include information
on the establishment and care
of the plant.
Once established, the time taken for blooms to be produced varies from 3-6
months in anthuriums and 6-9 months in heliconias.
There is a high demand for blooms locally and there is potential for the export
market. Flowers are used for bouquets, floral arrangements and exhibitions. Some
ornamentals are raised in flower beds in their natural setting in gardens, parks and
recreational areas.
21.4 Harvesting techniques of horticultural
plants
Harvesting techniques do not differ greatly from those used by farmers. As the plots
are smaller, most harvesting is done by hand so there is minimum damage from
machinery. The stages of maturity at time of harvest for vegetables, and manual
harvesting methods, were described in Chapter 13.
21.5 Quality requirements for flowers
Review Chapter 13 and make a list of the
equipment needed for the manual harvesting of
horticultural produce.
Flower producers need to supply the market with blooms in a state which will
satisfy the consumer. Ornamental crops need special harvesting techniques and
post-harvest treatment to ensure they reach the market in prime condition.
The blooms are harvested by cutting the stems with secateurs and placing them
in baskets. They are then transferred to a cool area for grading and storage.
Anthurium and heliconia
Hybrids of a nthurium may produce up to 12 flowers per year. Flowers are harvested
when the spathe is fully opened, the flower stalk is firm up to the bloom, and the
spadix (candle) is firm and rough with prominent seed buds. Using secateurs, cut
stalks 40 to 80 cm in length and place upright in baskets. Post-harvest handling
involves flowers being stored in a cool area and graded according to size, colour
and injury.
Heliconia blooms are treated in a similar way, but the flower stalks may be of
varying lengths.
Ginger lilies
Describe how ginger lilies are prepared for the
local market.
ITCI18
Why are flowers stored in a cool area before they
are sold?
Ginger lily blooms are cut off together with two leaves on the flower stalk. The
blooms are placed in a basket with flowers protruding upwards. The stalks are
placed with their basal ends in buckets, half-filled with clean water, in a cool place.
The blooms are later graded and placed in boxes for export or into small bundles,
and covered over with a clear polythene bag for the local market.
Orchids
Practical activity:
Harvest the ornamental plants that
you have cultivated.
•.
316
11101,11351,09.
Orchid sprays are cut with as long a stem as possible, including some buds and
flowers. The blooms are placed in a basket and transported to the storage area as
quickly as possible. The cut flowers may be placed into orchid tubes filled with
water to support the stems. They are carefully packed into boxes and stored in a
cool place.
21 Horticulture
21.6 The establishment of lawn and turf
grasses
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 seed bed. The soil is then graded, smoothed and levelled.
The plot is left to allow weed seeds to germinate. These can be removed by hand
or sprayed with a herbicide. Add lime and fertiliser and incorporate into the soil
before planting.
Figure 21.5 Bermuda grass.
Lawn establishment
Using seed
Grass seed should be bought from a reputable supplier, be of good quality and
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 determining the area of the lawn
and following the guidelines given by the seed suppliers. For example, Bermuda
grass is sown at the rate of 30-60 kg/ha (300-600 g/m 2 ) and savanna grass at
20-60 kg/ha (200-600 g/m 2 ). A high sowing rate will prevent weed development
during early stages of growth.
Using sod
Use of sod, or turf, for establishment of a lawn is the quickest method, but also
the most expensive. It 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 established.
sprigs ► Sprigs are pieces of turf containing a stolon and roots. They are sometimes
referred to as runners. The area needs to be prepared in the same way as a seedbed,
although the tilth does not need to be as fine. It should be weed-free. The density
of planting may be low or high, but the higher it is the more quickly the ground
will be covered. Sprigs can be planted 15 to 20 cm apart or broadcast over the
soil, followed by disking to partially cover them with soil. Sprigs can either be
purchased or bought as turf, which is then shredded to form the sprigs. A lawn
planted in this way will establish more quickly than one grown from seed.
plugs ► For fine-leaved species of grasses, plugs are used instead of runners. A plug is
a small piece of turf 5 cm across, containing shoots, roots and soil. It is made by
cutting up sod. One effective method of lawn establishment is to chop up runners
or sod, mix them with soil or peat, and spread over the surface of the area (lightly
covered and watered).
Fertilisers
Fertiliser application is usually needed to encourage vigorous growth and to keep
lawn fertilisers ► grass green. Lawn fertilisers are chemical compounds high in nitrogen and potash,
but low in phosphate (they also contain some sulphur). The fertiliser can be
applied as a top dressing, at a rate of 5 kg/200 m 2 . During establishment, fertiliser
317
Section D: Horticulture
should be added once a month at the same rate. It is best to add fertiliser during
cool periods of the day and to avoid using too much during the rainy season.
Watering
The lawn needs to be watered regularly once a day during the first month; and
twice a week after that, depending on the season. The grass species used are
tropical or sub-tropical and will tolerate drought to some extent, but if dry periods
are prolonged bare patches develop. If this happens, the lawn should be re-seeded
or the bare patches treated with plugs or sprigs so that weeds do not invade.
Pests and diseases
Name THREE grasses used in the establishment
of lawns
Pests and diseases are not common in lawns. Insect pests can be controlled by
using insecticides if necessary. Weeds can colonise bare patches, but if these are reseeded there should be no problem. Crab grass and nut sedge are the commonest
weeds of lawns. They can be removed by hand or the lawn can be treated with a
selective post-emergent herbicide, repeated at 1-2 weekly intervals if necessary.
Dead grass and leaves (thatch) can be raked out periodically.
Mowing
Why should fertiliser be applied to lawns?
Practical activity:
Establish and maintain a lawn or
turf area.
The first mowing is done when the grass has grown to a height of 5 cm. Regular
mowing depends on the rate of growth and the season, but can be repeated
weekly. The height of the grass is determined by the purpose of the lawn or turf
area. For example, bowling greens, the greens of golf courses and sports pitches
need a shorter turf than landscaped areas.
Mowing is done manually with a lawn mower, or mechanically. Lawn mowers
can be powered by electricity or gasoline. Large areas of landscaped grass are
usually mown using a special mowing machine or a mower pulled by a tractor.
•
•
•
•
•
•
•
•
•
•
•
318
Horticulture refers to the small-scale cultivation of crops. It includes the
cultivation and marketing of trees, flowers, fruit, vegetables and landscape
plants.
Horticultural plants supply food, medicines, ornamental plants and shade.
Management practices include propagation, planting, cultivation, harvesting
and marketing.
Understanding these practices is important in the cultivation of citrus, avocado,
mango, banana and ornamental plants.
Propagation is often by means of suckers, offshoots or grafting in order to
maintain desired varieties and quality of produce.
Harvesting and post-harvest handling is important to ensure that good quality
fresh produce is marketed.
Citrus trees should be planted in well-prepared soil, pests and weeds controlled
and fungicide applied to protect against scab. Fruits are rich sources of vitamin
C and are either eaten fresh, processed into juices or canned.
Mangoes grow best in full sun. They need protecting against insects and fungal
diseases during flowering and fruiting.
Avocados need protecting from pests such as rats and squirrels, infestations of
mites and fungal diseases. Avocados have a long ripening period on the tree
and fruits need to be mature but hard and green when harvested.
Bananas are pruned regularly so that only one mother plant with a follower
develops at each stool. Bunches are protected by 'sleeving' with polythene.
Miniature golden apples are propagated by using dwarf rootstocks. Fruit is
easier to harvest from the dwarf trees.
21 • Horticulture
• Omamentals are cultivated on raised or cambered beds. Some, such as orchids
and anthuriums, need to be in shaded humid conditions.
• The harvesting and post-harvest treatment of ornamentals is managed to
conform to the requirements of the market.
• Most horticultural produce is harvested manually and techniques do not differ
from those used by farmers on small farms.
• Special types of grass are used for the establishment of lawns and landscaped
areas.
• Grass seed may be sown on a prepared seed bed, but lawns can be established
using sod, sprigs or plugs.
• The grass needs to be watered regularly, fertiliser applied and pests and weeds
controlled.
• Mowing can be started when grass has reached 5 cm in height and should be
carried out regularly.
1101 Horticulture involves the cultivation of small plots rather than large
fields; there is a greater variety of crops with ornamental crops as well as
vegetable crops grown.
1102 Floriculture is the cultivation and marketing of flowers.
1103 Two from: Aloe vera, Mexican tea (Chenopodium ambrosioides) and peppers
(Capsicum). Accept any others that are local.
1104 To provide shade for the livestock so that they are not exposed to direct
heat from the sun.
1105 Leaf-cutting ants, aphids and black bees.
1106 Citrus crops are propagated by budding.
1107 Fruits are dipped in hot water and fungicide to prevent rotting during
storage, then graded and packed into crates. They are stored in a cool
place.
IT08 Mango trees have a dense canopy of leaves which provides shade from
the sun.
1109 Avocados are usually propagated by grafting because they take a long
time to grow from seed and produce fruit. Also suitable varieties can be
chosen so that quality and quantity can be maintained.
11010 Fruits are picked when mature but still hard and green. After harvest,
they are kept cool but will ripen in a few days if exposed to room
temperatures.
11011 Bananas are propagated by means of suckers.
11012 A polythene bag is placed around developing fruits to protect them from
injury.
11013 Golden apple trees are tall trees. If a dwarfing rootstock is used, the height
of the tree is reduced and cultivation is easier. It is easier to pick the fruit
and pest control treatments are more easily applied.
11014 Most ornamentals are propagated by offshoots or cuttings.
11015 Ornamentals are used in bouquets, floral arrangements and in flower
beds in parks and gardens.
11016 The manual equipment for harvesting horticultural produce should
include knives, machetes, cutlass, spade, fork, secateurs, baskets and
crates.
11017 Blooms are cut with two leaves on the flower stalk, placed into clean
water in a cool place, then put into bundles of six blooms and covered
with a polythene bag.
319
Section D: Horticulture
1T018 Flowers are placed in a cool area so that they do not lose too much water
and wilt.
11019 Bermuda grass, savanna grass and turf grass.
11020 Fertiliser is applied to lawns to encourage vigorous growth and to keep
the grass green.
Examination-style
questions
320
himl iana g efent
^, 11s
By the end of
3
this chapter
you should be
able to:
describe the management practices involved in the rearing of four
different farm animals
3
,/
rear layers and prepare a cost analysis of egg production
car ry out practical work with cows, rabbits, sheep or goats and pigs
3
describe the processes involved in the prevention of food spoilage
3
identify the major cuts of meat and their quality requirements
3
describe food safety in the processing of food
3
describe the use of animal products, by-products and wastes
3
discuss the role of biotechnology in animal production.
Concept map
Animal management
Management
practices
Reproduction
Food safety
requirements
Food spoilage
food preparation
Causes
areas
slaughter houses
Care of young
cooling
Housing
d ry ing
Health
pasteurisation
Cost of
production
Biotechnology in
animal production
Animal
products
Benefits
Animal byproducts
the consumer
Prevention
Feeding
disease prevention
disease control
handlina manure
Value-added
products
Concerns of
Animal wastes
UHT
curing
smoking
Recordkeeping
321
Section E: Animal Management
22.1 Management practices in the rearing of
livestock
Farm animals and their young need to be cared for and handled in a particular
manner, using scientific principles, so that farmers may:
• produce high quality livestock and livestock products
• improve the efficiency of their production
• increase output
• maximise their profits.
Caring for livestock and handling them require a good understanding of:
• breeding: male and female reproductive systems; oestrous cycle; fertilisation;
gestation; parturition (birth)
• care of the young
• feeding requirements: water; grass; concentrates; colostrum; milk
• housing requirements: spacing; ventilation; temperature; shade; ease of cleaning
• health issues: pests and diseases — prevention and control
• handling manure: removal; conservation; use (source of biogas or compost)
• record-keeping
• cost of production.
Rearing layers
Chickens are popular animals to raise on farms. There are several breeds and
hybrids which are reared locally for their meat (Vantress Cross, Byline), for eggs
( White Leghorns, Bevan Brown), or for both meat and eggs (Plymouth Rock,
Rhode Island Red). These birds are produced from hatching eggs on specialised
farms stocked with cock birds and hens. Fertile eggs are incubated and the day-old
chicks are purchased by farmers wishing to raise broilers for meat or layers for eggs.
Egg formation was described in Chapter 18, housing for layers in Chapter 17 and
care of the young chicks in Chapter 19.
Feeding
chick starter ►
pullet grower ►
layer ration ►
The feeding requirements of layers differ from those of broilers. Commercial feeds
contain ground-up oyster shells to provide the calcium that laying hens need to
produce strong egg-shells. There are three stages in the feeding regime for layers:
• from day 1 to week 6 they are fed on chick starter: fine-textured and granular;
contains 18-20% protein
• from week 7 to week 18 they eat pullet grower (growing mash): coarsetextured and pelleted, contains 15-17% protein
• from week 19 until the flock is culled or sold as ex-layers they are fed on layer
ration (laying mash): coarse-textured and pelleted, contains 14-16% protein.
Feeds vary in texture, composition and palatability and the changeover is done
gradually. For example, starter ration is mixed with grower ration over a period of
5 to 7 days to get birds accustomed to the different feed. Chicks are fed in flat tray
feeders, but tube feeders are introduced at 2 weeks of age, allowing two feeders
per 100 birds. The height of the tube feeders is adjusted regularly so that the base
is always level with the back of the birds.
The health of poultry, including pests and diseases, is described in Chapter 19.
Dealing with manure
poultry manure ►
322
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.
22 - Animal management
ame and describe the feed given to chicks from
ay 1 until they are 6 weeks old.
Rotted poultry manure is a fertiliser for the cultivation of vegetable crops, such
as ochro, pumpkin, tomato, cabbage and bodi bean. Bagasse-based poultry litter is
an ingredient in the feed of small ruminants, such as sheep and goats.
Record - keeping
t
ive one use of bagasse-based poultry litter.
p
ith reference to Chapter 19, describe how
nicks can be protected against Newcastle
disease.
Practical activity:
Rear a batch of layers and prepare
a cost analysis of egg production.
Use information from Chapters
17,18 and 19, together with the
information in this chapter, to
help you plan and carry out this
activity.
Poultry farmers should keep records which include:
• total number of chicks brooded
• mortality
• number of layers reared
• feeds and feeding regimes
• medication, vaccinations
• growth rate and feed conversion ratio (FCR)
• egg production: daily, weekly, monthly
• culling of layers: weight at marketing or slaughter
• income: from sale of eggs; sale of culled birds
• expenditure
• profit/loss
• cost of production.
The reproductive systems of farm animals (mammals)
The reproductive systems of sheep, goats, pigs, cattle and rabbits are all very similar.
The male reproductive organs of rams, boars and bulls consist of:
testes ►
• a pair of testes (singular – testis):
sometimes referred to as testicles;
seminal vesicles
produce
sperm; produce testosterone
prostate gland
vas deferens
( male sex hormone)
• the scrotum (scrotal sac): holds
the testes; provides a favourable
spermatic cord
temperature for the development of
urethra
the sperm
r ^^
• the epididymis: connects the testes to
the vas deferens; the location where
—^^
sperm become mature; stores sperm
retractor penis muscle
prepuce
before ejaculation
sigmoid flexure
testicle (testis)
• the vas deferens: propels the sperm
from the epididymis to the urethra
epididymis –
scrotum
during ejaculation
• the urethra: connected to the vas
deferens; enables sperm to be
Figure 22.1 The male reproductive organs (bull).
ejaculated through the penis; allows
the passage of urine through the
penis
• the seminal vesicles: produce semen which nourishes the sperm, is a transport
medium for sperm and a buffer against the acidity of the female genital tract
• the prostate gland: produces an alkaline secretion; helps to give semen its
characteristic odour
penis ► • the penis: enables transfer of sperm into the female genital tract
• the prepuce: covers and protects the penis.
The female reproductive organs of farm animals, such as sows, ewes and cows,
consist of:
ovaries ► • two ovaries: produce the ova or eggs (the female gametes); produce hormones
which control the oestrous cycle and pregnancy
• the infundibulum: funnel-shaped structure: receives the egg from the ovary
and channels it into the oviduct or fallopian tube
• the oviduct (fallopian tube): conducts the ovum to the horn of the uterus; it is
the usual site of fertilisation
323
Section E: Animal Management
uterus ►
Describe the structure and function of the
scrotum.
In which part of the male reproductive system are
sperm stored before ejaculation?
• the uterus (womb): receives the fertilised ovum (zygote); the zygote implants
within the uterine wall; provides conditions for nurturing the zygote; enables
the zygote to develop into an embryo and eventually an offspring
• the cervix (neck of the uterus): relaxes slightly at oestrus to allow sperm to
enter during mating; produces mucus which prevents infective material from
the vagina entering the uterus during pregnancy
• the vagina: serves as the channel for the penis during mating; serves as the
terminal section of the birth canal; allows the birth of the offspring
• the vulva: extends from the vagina to the exterior, forming the labia or lips;
indicates the entry to the vagina.
State the function of the infundibulum.
Where does fertilisation usually take place?
Where is the cervix and what are its functions?
infundibula
1
uterus (womb)
vagina
ovaries
cervix
Practical activity:
vulva
oviducts (fallopian tubes)
Using this chapter and the
information in Chapter 18, identify
the signs of heat in farm animals.
Figure 22.2 The female reproductive organs (cow).
The oestrous cycle, oestrus, ovulation and gestation are described in Chapter 18.
Rearing sheep and goats
Sheep and goats are small ruminants which require a smaller area of land for
commercial rearing than cattle. They graze pastures to a low level and browse on
the leaves and twigs of shrubs and other forage plants. Locally, goats are reared
for milk, meat and skins, whereas sheep are reared mainly for meat (mutton and
lamb) and skins. In certain parts of the world, sheep are reared for their milk and
wool. The Caribbean area, comprised of small island states with hilly terrain and a
tropical climate, is well-suited to goats and sheep.
The goat produces milk which is:
• as nutritious as cow's milk
• richer in phosphorus and vitamin B1 (thiamine)
• composed of smaller fat globules than cow's milk
• widely used for children and people recuperating from illness.
Figure 22.3 Goats are sometimes
referred to as the 'poor man's cow'.
State THREE ways in which goat's milk differs
from cow's milk.
324
Fresh goat's milk, curried goat meat and lamb stew are very popular in the
Caribbean.
Breeds of sheep are Barbados Black Belly and Blackhead Persian, and breeds of
goats include Toggenburg and Anglo Nubian. Other breeds are listed in Chapter 18.
Sheep and goats are bred at 10 to 12 months of age. Animals may be cross-bred,
mating males and females from different breeds, or purebred, mating males and
females from the same breed. Males and females should not be related. Young
males, about 4 months of age, can impregnate females on heat; so young males
should be separated from the flock and not used for breeding until 10 to 12 months
old, in good health and physically mature.
Females come on heat every 21 days. The signs of heat and gestation periods for
goats and sheep are described in Chapter 18. A mature buck or ram, about 2 years
of age, may service five does or ewes per week. If mating is successful, the young
are born in 150 to 153 days. Goats and sheep usually give birth to two young per
pregnancy.
22 • Animal management
Explain why Iambs' tails are docked'.
castration ►
I
When about to deliver, the female should be moved to a separate pen in a quiet
area and provided with bedding of straw, bagasse or wood shavings. Fresh feed and
clean water are provided regularly. As the young are born, mucus around the nose
and mouth should be wiped away with a clean cloth. The umbilical cord is tied,
cut and painted with iodine to prevent infection. The young are then dried and
kept in a warm area, away from draughts. Following delivery of the afterbirth, the
mother is cleaned, soiled bedding removed and the young suckle her to obtain the
first milk, the colostrum. The afterbirth is burnt or buried.
The young are usually fed four times a day with milk at 37.8°C, using a plastic
bottle with a nipple or from a bucket. A starter ration of concentrate is introduced
when they are 1 week old, but overfeeding should be avoided as it may cause
scouring. The young are fed whole milk for at least 2 weeks after birth, following
which a milk replacer can be used. By 2 weeks of age, they should be eating green
forage and starter ration. Weaning can be around 8 weeks of age or when they
weigh 10 to 12 kg. If left with their mothers, the young may not be weaned until
5 to 6 months old.
Kids or lambs may undergo these procedures:
• disbudding: used to prevent the growth of horns; a caustic paste is applied to
each horn button when the kids or lambs are 1 week old
• ear-tagging: an ear tag, bearing letters and numerals for identification, is
attached
• castration: male animals not required for breeding are castrated; this prevents
indiscriminate breeding
• docking: tails are removed from lambs to prevent faeces sticking to the wool
(pinning) and 'glueing' the tail to the body.
Housing
The general requirements for farm animals are described in Chapter 17. Buildings
for sheep and goats should allow 1.5 to 2.5 m 2 of floor space per animal, be equipped
with water buckets in a frame to prevent toppling, have feeders for concentrates
and wooden racks for green forage.
Rearing systems
Goats and sheep may be reared:
• intensively: this system is used where land is limited; animals are kept in pens;
zero grazing is used; concentrates are given; pens and equipment are cleaned
daily; droppings and other waste are removed for composting
• semi-intensively: animals graze on pasture during the day; they are housed
and given additional feed during the evening and night; this requires
cultivation of pasture
extensively: animals are kept on pasture continuously; housing is only
provided for sick animals, giving birth and caring for the young; minim al
quantities of concentrates are given; shade trees or open sheds and clean water
are provided.
The labour costs associated with systems of rearing vary: costs are high for intensive
systems and lower for the semi-intensive as animals do not have to be fed during
the day. Extensive systems may be the cheapest, but there is a high risk of praedial
larceny.
Feeding
After weaning, goats and sheep are provided with green forage (grasses, legumes,
leaves and twigs of shrubs), concentrates, mineral licks and water. In addition,
they may be given by-products, such as bagasse, molasses, bagasse-based poultry
litter, poultry by-product meal, rice bran, coffee hulls and dried, crushed cocoa
pods. In allocating feed, consideration is given to the stage of development of the
animals, their body weight and any physiological condition, such as pregnancy.
Clean drinking water is provided at all times, on the pasture and in their stalls.
325
Section E: Animal Management
Disease management
To prevent pests and diseases, 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 given at all times
• animals are de-wormed regularly
• wheel baths and foot baths are used on farms
• hooves of the animals 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
• animals are protected from dogs, especially sheep
• sick animals are isolated and treated.
foot rot ►
nutritional scours ►
white scours ►
Foot rot is a disease caused by both fungi and bacteria. It causes lameness and the
soft tissues become swollen and inflamed. Infected tissue should be removed, the
hoof washed in antiseptic solution (e.g. Dettol) and a solution of copper sulphate
applied. The animal should then be kept on a dry floor until healing is completed.
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 yellowish-white,
smelly faeces. Affected animals should be isolated, pens and all equipment should
be sterilised, and the hooves should be washed in antiseptic solution.
Cleaning
The dung and soiled bedding are swept up, loaded on to a wheelbarrow and
taken for composting. These can afterwards be spread on to ploughed land and
incorporated into soil for crop cultivation.
1T011 Describe how internal parasites and
external parasites are treated in sheep and goats.
What causes nutritional scours and how can it be
treated?
Record-keeping
Record-keeping is similar to that for other farm animals. Identification using
numbered ear tags is essential so that records are meaningful and the farmer can
calculate the cost of production.
Pigs
Pigs are reared for their meat (pork and bacon). Landrace and Large White are
reared for pork and Tamworth for bacon. Sows come into heat about every
21 days. If fertilisation is successful, the gestation period lasts 110 to 117 days.
Pregnant sows are kept in sow stalls or separate from the other pigs. When about
to deliver, the sow is moved to a farrowing stall so that piglets are not damaged
by her moving around. The farmer or farming assistant should be present during
farrowing and the usual procedures of caring for the mother and newborn piglets
should be taken. The piglets are encouraged to suckle as soon as possible.
Rearing piglets
Figure 22.4 The piglets are protected
by guard rails to prevent the sow
crushing them.
326
Management practices include:
• clipping needle teeth: to prevent injury to the teats of the sow
• iron injections: prevent piglet anaemia and promote rapid weight gain
• creep feeding: piglets are fed concentrates in an area surrounded by guard rails
to protect them from being crushed by the sow
• castration: this is the removal of the testes in male piglets not required for
breeding; this promotes rapid weight gain
22 - Animal managemer,
• docking: the piglet's tail is cut off; this prevents tail-biting in the herd;
promotes rapid weight gain
weaning ► • weaning: suckling is prevented
• dealing with runts: weak piglets (runts) may be slaughtered soon after birth.
Piglets are removed from their mother when 2 to 5 weeks old and transferred to
grower barns.
Rearing older pigs
Pigs may be reared:
• intensively: kept in barns — straw-lined or with slatted floors; may be
in individual stalls so that each pig has its own ration and medication;
temperature is controlled so that pigs are not stressed by heat or cold
• extensively: pigs are housed outdoors and allowed to move freely on pasture;
shelter and feed are provided; pigs need to be protected against sunburn so
shade is needed; this system is usually used for sows and their piglets: piglets
are sent to growing units after weaning; the area needs to be fenced; this
method is used on arable farms as part of a rotation; the field which has
benefited from pig dung can be used to grow crops.
Feeding
Pigs are fed on grains and protein sources. Creep feed is given to the piglets before
they are weaned. From 6 weeks, they are given a starter ration and fed on this
until they reach 30 kg. Grower ration is given until they reach 50 kg; they are then
fed on finisher ration until they reach their market weight, usually 60 kg. Pregnant
sows are fed a special ration for 2 to 3 months before they give birth. The starter
rations contain more protein than the finisher, so are more expensive.
Disease management
Name FOUR management practices used in the
rearing of piglets.
Why is the temperature controlled in intensive
pig-rearing systems?
a
Explain why the provision of shade is necessary
when pigs are reared outdoors.
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.
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.
Record-keeping
As with other farm animals and enterprises, record-keeping is necessary.
Cattle: beef and dairy
Cattle are reared to supply milk and meat. Some breeds have been developed for
meat production, such as Jamaica Red, Jamaica Black and Buffalypso; others have
been developed for milk production, such as Jamaica Hope and Holstein.
Cows are usually artificially inseminated with semen from a bull with desirable
characteristics at the time of oestrus. The gestation period averages 280 days. The
calf and mother are cleaned after the birth and the calf suckles to obtain colostrum.
Colostrum is needed so that the calf develops immunity against diseases.
327
Section E: Animal Management
Disease management
To prevent pests and diseases, 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 given at all times
• animals are de-wormed regularly
• wheel baths and foot baths are used on farms
• hooves of the animals 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
• animals are protected from dogs, especially sheep
• sick animals are isolated and treated.
foot rot ►
nutritional scours ►
white scours ►
Foot rot is a disease caused by both fungi and bacteria. It causes lameness and the
soft tissues become swollen and inflamed. Infected tissue should be removed, the
hoof washed in antiseptic solution (e.g. Dettol) and a solution of copper sulphate
applied. The animal should then be kept on a dry floor until healing is completed.
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 yellowish-white,
smelly faeces. Affected animals should be isolated, pens and all equipment should
be sterilised, and the hooves should be washed in antiseptic solution.
Cleaning
The dung and soiled bedding are swept up, loaded on to a wheelbarrow and
taken for composting. These can afterwards be spread on to ploughed land and
incorporated into soil for crop cultivation.
IM11 Describe how internal parasites and
external parasites are treated in sheep and goats.
Record-keeping
in112
Record-keeping is similar to that for other farm animals. Identification using
numbered ear tags is essential so that records are meaningful and the farmer can
calculate the cost of production.
What causes nutritional scours and how can it be
treated?
Pigs
Pigs are reared for their meat (pork and bacon). Landrace and Large White are
reared for pork and Tamworth for bacon. Sows come into heat about every
21 days. If fertilisation is successful, the gestation period lasts 110 to 117 days.
Pregnant sows are kept in sow stalls or separate from the other pigs. When about
to deliver, the sow is moved to a farrowing stall so that piglets are not damaged
by her moving around. The farmer or farming assistant should be present during
farrowing and the usual procedures of caring for the mother and newborn piglets
should he taken. The piglets are encouraged to suckle as soon as possible.
Rearing piglets
Figure 22.4 The piglets are protected
by guard rails to prevent the sow
crushing them.
326
Management practices include:
• clipping needle teeth: to prevent injury to the teats of the sow
• iron injections: prevent piglet anaemia and promote rapid weight gain
• creep feeding: piglets are fed concentrates in an area surrounded by guard rails
to protect them from being crushed by the sow
• castration: this is the removal of the testes in male piglets not required for
breeding; this promotes rapid weight gain
22 • Animal management
• docking: the piglet's tail is cut off; this prevents tail-biting in the herd;
promotes rapid weight gain
weaning ► • weaning: suckling is prevented
• dealing with runts: weak piglets (runts) may be slaughtered soon after birth.
Piglets are removed from their mother when 2 to 5 weeks old and transferred to
grower barns.
Rearing older pigs
Pigs may be reared:
• intensively: kept in barns — straw-lined or with slatted floors; may be
in individual stalls so that each pig has its own ration and medication;
temperature is controlled so that pigs are not stressed by heat or cold
• extensively: pigs are housed outdoors and allowed to move freely on pasture;
shelter and feed are provided; pigs need to be protected against sunburn so
shade is needed; this system is usually used for sows and their piglets: piglets
are sent to growing units after weaning; the area needs to be fenced; this
method is used on arable farms as part of a rotation; the field which has
benefited from pig dung can be used to grow crops.
Feeding
Pigs are fed on grains and protein sources. Creep feed is given to the piglets before
they are weaned. From 6 weeks, they are given a starter ration and fed on this
until they reach 30 kg. Grower ration is given until they reach 50 kg; they are then
fed on finisher ration until they reach their market weight, usually 60 kg. Pregnant
sows are fed a special ration for 2 to 3 months before they give birth. The starter
rations contain more protein than the finisher, so are more expensive.
Disease management
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.
Name FOUR management practices used in the
Animals kept outdoors are more prone to worms and parasites. Dips, sprays and
rearing of piglets. 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.
Why is the temperature controlled in intensive
Pigs can be affected by respiratory diseases such as pneumonia and swine
pig-rearing systems?
influenza. Affected animals are separated from the herd, kept warm and dry and
given antibiotics.
Explain why the provision of shade is necessary
when pigs are reared outdoors.
Record-keeping
As with other farm animals and enterprises, record-keeping is necessary.
Cattle: beef and dairy
Cattle are reared to supply milk and meat. Some breeds have been developed for
meat production, such as Jamaica Red, Jamaica Black and Buffalypso; others have
been developed for milk production, such as Jamaica Hope and Holstein.
Cows are usually artificially inseminated with semen from a bull with desirable
characteristics at the time of oestrus. The gestation period averages 280 days. The
calf and mother are cleaned after the birth and the calf suckles to obtain colostrum.
Colostrum is needed so that the calf develops immunity against diseases.
327
I
Section E: Animal Management
Other management practices for the rearing of calves include:
• bucket feeding milk: to encourage weight gain
• providing a corral: a fenced area with pasture grass where calves can feed and
exercise
• de-worming: force the calves to swallow a drench containing a helminthic
( worm medicine) to get rid of intestinal worms
• castration: the testicles of male calves are removed with a burdizo; this makes
the calves sterile; it encourages rapid weight gain; calves become more docile
after castration
• weaning: calves are no longer milk fed; with dairy cattle, the new-born calves are
taken from their mother immediately and transferred to calf pens, 2 m x 1.5 m.
Housing
Housing is described in Chapter 17 and grazing systems in Chapter 16. Additional
housing, such as calf pens for new-born calves and larger community pens, are
needed on a dairy farm. Calf pens are used until the calf is 5 to 8 weeks old. These
usually have slatted floors or dried grass bedding, with a feeding bucket and water.
On large dairy farms, cows are milked by machine in a milking shed (or milking
parlour). The shed is divided into stalls. As the cows enter the shed, their udders are
washed and the teats of the milking machine are attached. The milk is withdrawn
into a collecting jar and the volume from each cow is recorded. All equipment is
sterilised after each milking session.
Feeding
Figure 22.5 A cow being milked by
machine.
For beef cattle, calves are fed forage and concentrates until they reach 200 kg. Their
weight gain then depends on whether they are turned out to pasture or whether
they are reared in an intensive system. In intensive systems, feed is controlled and
the diet consists mainly of cereal feeds. High weight gains are achieved as the cattle
are not using energy to graze. In dairy herds, the nutritional content of the feed is
critical so that the cows are able to produce high quality milk. A mixture of hay,
silage, root crops and concentrates is given in intensive systems. Cows which graze
on pasture are given concentrates and additional feed if the pasture is poor.
Health problems
Pests and diseases of cattle include:
• external parasites: lice, ticks and mites; cause irritation, suck blood and may
cause mange; treated and prevented by sprays or dips; good housing and
hygienic conditions can prevent infestations
• bacterial infections: mastitis causes sore, inflamed udders and affects the milk;
treated with antibiotics
• foot and mouth disease: caused by a virus; affected animals have to be
slaughtered; can be prevented by vaccination
• coccidiosis: caused by a protozoan; causes diarrhoea in young cattle; can
spread from adults to calves; treated with sulphur drugs and good hygiene.
Using manure
Manure is gathered up and used as fertiliser on ploughed land. It can also be used
to generate biogas.
Milk production
calving cycle ►
Milk production is linked to the calving cycle (see Figure 22.6). Lactation starts at
the birth of a calf. The length of lactation depends on the timing of the birth of the
next calf. Before the next calf is born, there is usually a drying-off period when
the cow is not milked; this allows recovery from the demands of producing milk.
The dairy farmer manages the herd so that cows are mated at the appropriate
time after the birth of a calf, usually about 6 weeks. This ensures a continuous
supply of milk from the herd. The daily yield of milk from a cow reaches a peak
4-6 weeks after the birth of the calf and then gradually falls. The volume of milk
produced can vary with the season, the feed and the frequency of milking.
328
22 • Animal management
What are the benefits of castrating male calves?
Explain why dairy cattle and beef cattle are fed
differently.
Experiments have been done in which cows are milked three times a day instead
of twice. Although the milk yield increases, the costs of labour and increased feed
do not always justify the practice.
Factors which affect the composition of the milk include the:
• breed of the cow
• age of the cow
• health of the cow
• feed given
• stage of lactation.
Lactation period
I
I
milk production
increases until 8 weeks
i
after the calf is born
8
10
'
pregnancy
milk production slowly
decreases in the last
7 months of lactation
M
6
the calf grows
very quickly
8
-
8
milk production
m
I
C
I
p
lactation stops when
the cow is dried off'
2
weight of
fetus
4
y
I
I
-
I
I
I
I
2
a calf is born and
milk production
(lactation) starts
0
I
the fetus is growing
inside the cow
2
1
I
6 m
4
the cow is made
pregnant
I
2
4
3
5
6
7
8
9
10
11
12
2
Months
Figure 22.6
What is mastitis and how can it be treated?
The calving cycle and milk production.
Buffalypso
Buffalypso ► Buffalypso are cattle which have been developed from water buffalo. They are
reared mainly in Trinidad and Tobago for their high quality meat and milk. The
meat is low in cholesterol so is particularly healthy. Their hides provide leather
for shoes, belts and handbags. The breed is free from the major diseases which
affect other livestock in the region. Heifers are mated when 21 months of age
and weighing around 350 kg. Calves are weaned at 4 months when they have
reached 80 kg. A cow can produce a calf every 21 months. The breed is still being
developed to improve milk production.
Practical activities:
Suggest the benefits of the development of the
Buffalypso breed.
,y
1. Carry out some practical work with cows, rabbits, sheep or goats and pigs. This
can be achieved by arranging to spend a day on a local dairy farm or other farms
where sheep, goats or pigs are reared.
2. Choose one of the animals described in this chapter and produce a written report
describing its characteristic features, how it is reared and the use of its products.
You may need to refer to information in other chapters.
329
Section E: Animal Management
22.2 Preventing food spoilage
Fresh food can be spoilt by micro-organisms, by enzyme activity in the tissues of
the food, and by oxidation. Micro-organisms cause food to decay. The oxidation
of fats makes foods (such as butter) taste rancid. This spoilage may be delayed
for short periods of time by using preservation techniques; some techniques can
preserve food for months and even years.
Cooling
cooling ►
freezing ►
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 pathogenic (disease-causing) 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 involves keeping food at minus temperatures. Meat and fish may
be frozen and stored at -18°C to -20°C. Freezing inhibits enzyme action and the
growth of bacteria, but the formation of ice crystals in tissues can alter the texture
of the product.
Micro-organisms are not killed by cooling or freezing, so microbial activity will
resume when food reaches a suitable temperature.
Drying
drying ►
Name the causes of food spoilage.
State the temperature at which fresh food should
be stored in the home and explain why storage at
this temperature is effective.
Explain how drying food prevents food spoilage.
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, the
texture and taste are changed. The microorganisms are not killed by drying, so
spoilage occurs when the water content
of the food reaches a certain level.
Figure 22.7 Drying is also used for
preserving fruits and vegetables — here
tomatoes are shown.
Pasteurisation
pasteurisation ►
The pasteurisation of milk is described in Chapter 20. Pasteurisation also preserves
fruit juices, wine, eggs and cream for a short period of time. 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 in a
heat exchanger system which is surrounded by water kept at just above 72°C,
held for the correct time, and then rapidly cooled to 3°C. Pasteurised milk and
pasteurised juices should be kept refrigerated between 1°C and 4°C. The benefits
of pasteurisation are that nutritional content and flavour are not altered by the
exposure to the temperatures used.
UHT (Ultra High Temperature)
UHT treatment ►
330
UHT treatment exposes milk and juices to 132°C for a few seconds to bring about
sterilisation. The milk is packaged into cartons, which are sealed under aseptic
conditions, and has a storage life of several months. The vitamin and mineral
content is not altered significantly.
22 • Animal management
Curing
curing ► 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, inhibiting 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 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 cured sometimes in this way. Bacteria are killed and the meat retains
a pink colour and 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 ► 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.
List the compounds used in the curing of food.
Now smoking is mostly used to impart 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
What is hot smoking'7
the smoking of oily fish.
Smoking is carried out in a smoker, consisting of a fire box and a food box. The
smoke is produced by a fire in the fire box and 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 which 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, then the food dries out and becomes
stringy. Hams and hocks are smoked in this way.
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.
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.
331
Section E: Animal Management
22.3 Principal cuts of meat
Practical activities:
The principal cuts of meat are described and illustrated in Chapter 20.
1. Review the section on cuts of
meat in Chapter 20 and watch
video presentations which
demonstrate the different cuts.
2. Visit a local store or
supermarket and observe the
butchering of carcasses and
the presentation of different
cuts of meat.
22.4 The quality requirements of meat
The livestock producer aims to rear animals that provide meat which is acceptable
to the consumer. The demand for meat is high as it is an important source of
protein.
Consumers are prepared to pay a good price for meat that:
• is fresh from the farm
• contains little fat: there is now more emphasis on the production of lean cuts
as these are considered to be more healthy; some fatty tissue is needed for
flavour and for satisfactory cooking of some cuts
• is organically produced: meat can only be designated organic if it has been
reared without the use of chemicals or growth stimulants.
Beef
Meat carcasses are inspected after slaughter and graded according to quality.
quality ►
yield ►
quality grades ►
Whole beef carcasses are graded for quality (tenderness, juiciness and flavour) and
for yield (amount of usable meat from the carcass).
The quality grades are:
• prime grade: produced from young, well-fed beef cattle; meat is marbled (has
some fat interspersed among the muscle tissue); prime roasts and steaks
• choice grade: high quality with less marbling than prime; roasts and steaks will
be tender; other cuts are better suited to braising
• select grade: uniform in quality and leaner than the higher grades; less
marbling so less flavour than higher grades
• standard and commercial grade: ungraded or 'store brand' meat
• utility, cutter and canner: 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 to fat.
Lamb
Usually only two grades, prime and choice, are retailed. The best lamb comes from
animals about 1 year old. Meat from older animals is graded as good, utility or cull.
Pork
R025
Describe the properties of good quality pork.
f 026
What are the features of Grade A poultry?
Practical activity:
Poultry
Visit your local store and assess
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.
the quality of different cuts of
meat and poultry offered for sale.
332
Pork is produced from young animals 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.
22 • Animal management
22.5 Safety requirements in the processing of
food
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 which could cause disease.
Food preparation areas
Figure 22.8 Workers in a foodprocessing plant.
In general, all food preparation areas and equipment are cleaned and ste ri lised
on a regular basis. This involves chlorine bleach, ethanol or sterilisation by ultraviolet (UV) light. People who work in food processing industries wear protective
clothing, such as overalls, gloves and boots, and have their hair covered.
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 which could introduce
bacte ri a 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.
If meat and meat products are being processed, it is usual for a food inspector to
be present.
Slaughter houses
sanita ry measures ►
`
Ex^why
p food processing areas should be
well-ventilated.
Name FOUR items of protective clothing used by
workers in the food-processing industry.
In slaughter houses, or abattoirs, strict hygiene is obse rv ed. All carcasses are
inspected and stamped as either fit for human consumption or unfit, in which
case they are burnt or bu ri ed. By obse rv ing sanitary measures (hygiene measures),
consumers are protected from meat-borne diseases.
The slaughter houses have the following features:
• well-ventilated and fly-proof
• a non-slippery, tiled or concrete floor that is slightly sloping for easy cleaning
• a chiller or cooling room for meat carcass storage
• a drainage system to collect solid and liquid waste.
After the animals have been slaughtered, the slaughter house and all equipment is
cleaned and washed thoroughly.
22.6 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:
• better marketing of animal products
• making use of by-products
• making use of animal wastes.
Better marketing of animal products
Farmers can make a greater profit from their produce if they:
• sell direct to consumers in farmers' markets, local stores and supermarkets
(rather than selling more cheaply to a wholesaler)
333
Section E: Animal Management
• sell prime and choice cuts of their meat directly to hotels and restaurants
• rear and market a particular breed of animal known for its flavour or
succulence
• market their produce as coming from a particular region
• obtain organic certification and market their meat, eggs and milk as 'organic'
• produce and market their own processed foods, such as yoghurt, ice cream
and cheese
• develop a brand name and market their labelled produce.
There is also profit to be made from the sale of:
• laying hens past their productive peak
• semen from pedigree males, such as bulls and boars: this can be used for
breeding
• hive products: royal jelly, wax and propolis.
List FOUR ways in which a farmer can make
greater profits from animal products.
Explain how co-operatives can reduce the costs
of farm production.
The role of co-operatives
The costs of rearing livestock, and providing housing, feed and medication, are
borne by the individual farmer; but costs of slaughtering, processing plants and
transport can be reduced if farmers form local co-operatives, where facilities are
shared. See Chapter 6 for more about co-operatives.
Making use of animal by-products
Some by-products of livestock production can be profitably used. These include:
• offal: organs such as kidney, liver, brain and heart; used for human food or pet
food
• hides: skins of slaughtered animals; leather products, such as handbags, belts,
shoes
• feathers and hair: feathers used for pillows and cushions; for insulation; hair
used as stuffing
• bones and blood: converted into bone meal and blood meal; used in animal
feed; used as fertilisers
• fat: rendered down from carcasses; used to make lard for cooking and soaps
• hooves and horns: ground up; used as fertilisers
• meat scraps: used to make pet food.
Name TWO uses of bones and blood from
animals.
All these by-products can be separated from the bodies of the animals and sold to
specialist producers.
Animal wastes
It was previously good practice to burn or bury carcasses and wash away blood
from slaughter houses. 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 waste (dung and litter) to make manure which
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 (specialising 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, is converted to feed
for poultry
• hatchery by-products: egg-shells are crushed and used to add calcium to
animal feed
334
22 • Animal management
• feathers are processed into feed: bacteria break down protein in the feathers;
the protein is then incorporated into the animal feed
• carcasses of large animals are rendered down and different parts used to make
animal feed.
Name a use for egg-shells from hatcheries.
The conversion of animal waste into animal feed is carried out in processing plants,
often owned and run by local co-operatives. The wastes are milled (ground up),
mixed with other feed components and formed into pellets.
Biogas
The use of manure to produce biogas is described in Chapter 20. The economic
advantage of this is that fuel costs are reduced. Biogas is used widely throughout
How are animal wastes converted into animal
the world, especially in isolated areas where individual farmers have biogas
feeds?
biofuels ► generators. In the Caribbean the production of biofuels from plant waste is already
well established.
22.7 The role of biotechnology in animal
production
The role of biotechnology is described in Chapter 18. However, the use of genetic
engineering in the production of meat, eggs and milk has raised concerns.
Benefits of using biotechnology
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 xenotransplantation (the transplantation
of cells, tissues and organs from one species into another species); this area
is linked with the growth of replacement human organs, particularly in
genetically modified pigs
• research into the role of genes in human diseases such as cystic fibrosis and
multiple sclerosis
• improved properties in those crop plants used in the manufacture of animal
feeds.
IK
Name TWO benefits of biotechnology in animal
production.
i
Suggest TWO concerns about the use of animals
in genetic engineering.
Practical activity:
Organise a debate on the role
of biotechnology. Or you could
prepare group presentations
on aspects of the role of
biotechnology.
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 using biotechnology
Concerns have been expressed about:
• the failure of treated embryos to survive
• the failure of introduced genes to be transferred
• the production of animal clones and the long-term effects of this
• 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.
The use of biotechnology in animal production is at an early stage. More research
is needed but both the quality and quantity of food might be improved by this
means.
335
Section E: Animal Management
4:1111M)
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Scientific principles and procedures are used by farmers to produce quality
livestock and livestock products. These procedures lead to increased efficiency
and greater profits.
Management practices include breeding, care of the young, feeding and housing
requirements, health and record-keeping.
Fresh food can be spoilt by micro-organisms, enzyme action and oxidation.
Cooling fresh food and keeping it at a low temperature can delay spoilage for a
few days as low temperatures inhibit bacterial growth.
Drying food reduces the water content and stops the growth of micro-organisms.
In warm countries, food can be dried outside; otherwise, drying is achieved by
forcing hot air over food.
Milk and other foods can be pasteurised. In this process, pathogenic bacteria are
destroyed but the flavour and qualities of the product are not significantly altered.
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.
Curing preserves meat and fish by using salt, sugar, nitrates and nitrites.
Food can be preserved by smoking, which is a form of dehydration which adds
flavour.
After slaughter, carcasses are inspected and graded according to their quality
and the yield of product.
Quality grades take into account the tenderness, juiciness and flavour of the
meat. They range from prime (the best) to utility, cutter and canner (used in
meat processing).
Pork is not graded in this way as pigs are bred to produce uniform carcasses.
The appearance and texture of the meat is described instead.
There are food safety requirements for the processing of food. Food handling
areas and equipment should be cleaned and sanitised regularly. Employees
should wear protective clothing. All premises should be well-ventilated, have
washable walls and floors and be screened to prevent entry of birds and other
animals.
Farmers could gain more money by changing methods of marketing their produce.
Farmers can profit from selling the by-products of animal production such as
hides, hooves, horns and bones.
Animal wastes, such as poultry litter, can be made into feed for livestock.
Animal wastes can be used as fertiliser or to generate biogas.
The role of biotechnology in animal production is controversial. There are
benefits to the consumer but also concerns about animal welfare.
IT01
They are given chick starter feed which is fine-textured and granular; it
contains 18-20% protein.
ITQ2 Bagasse-based poultry litter can be used in the feed given to small
ruminants such as sheep and goats.
MD Young chicks can be vaccinated against the disease. All housing and
equipment should be cleaned and disinfected.
ITN The scrotum is a sac containing the testes; it holds them outside the body
so they are at the right temperature for sperm production.
1105 In the epididymis.
1106 The infundibulum receives the egg from the ovary and channels it into
the oviduct.
336
22 • Animal management
1107 Fertilisation usually takes place in the oviduct.
1108 The cervix is the neck of the uterus; it allows sperm into the uterus
during mating; it secretes mucus to prevent entry of infective material
into the uterus during pregnancy.
1109 Goat's milk has smaller fat globules, more phosphorus and more vitamin
B 1 than cow's milk.
11010 Lambs' tails are 'docked' or cut off to prevent faeces sticking to the wool
and blocking the anus so that they cannot eliminate their faeces.
11011 Internal parasites are treated by de-worming sheep and goats. External
parasites are treated by spraying animals or spraying the pasture to get rid
of, or reduce the numbers of, ticks and mites.
ITQ12 Nutritional scours is caused by overfeeding and unsanitary conditions. It
is treated by giving olive oil, mineral oil or baking soda and by thorough
cleaning of housing.
11013 Four from: clipping needle teeth; creep feeding; castration; docking; iron
injections; weaning.
11014 Pigs are stressed by extremes of temperature, so the temperature is
controlled so that pigs are kept warm and do not use up (waste) energy
in keeping warm.
11015 Shade is necessary to protect pigs from the sun (they may get sunburn).
11016 The calves are more docile and they gain weight more quickly.
11017 Dairy cattle are given feed which encourages milk production and it is
lower in protein. Beef cattle are given high protein feed to encourage
muscle (meat) formation.
11018 Mastitis is an infection of the udders in a cow and is treated by giving
antibiotics.
ITQ19 The Buffalypso produces excellent meat and milk and is also less
susceptible to the diseases which affect other livestock.
ITQ20 Food is spoiled by decay caused by micro-organisms, continued enzyme
action in the tissues of the food, and by oxidation.
ITQ21 Fresh food should be stored at 1-4°C; at this temperature bacteria do not
multiply.
11022 Drying removes water — and water is needed by bacteria and other microorganisms for growth.
11023 Salt, sugar, nitrates and nitrites are used in curing food.
IT024 In 'hot smoking', food is placed in a smoker and exposed to temperatures
between 75°C and 85°C.
11025 Good quality pork should have a firm texture, be greyish pink, have a
thin layer of fat on the outside and the fat should be firm and white.
ITQ26 Grade A poultry should not be bruised or discoloured, the flesh should
be meaty and the skin should not be broken. There should be no feathers
left in and no broken bones in joints.
11027 Food processing areas should be well-ventilated so that condensation does
not drip on to food products and surfaces and contaminate them.
11028 Any four from: overalls, hats, boots, gloves, hair nets.
11029 Four from: sell directly to consumers; sell to hotels and restaurants; farm
organically; raise and market selected breeds; produce processed food
products on the farm.
11030 Co-operatives can reduce the cost of farm production by sharing facilities
such as feed processing mills, slaughter houses and other food-processing
plants.
337
Section E: Animal Management
ITC131 Bones and blood can be made into fertilisers or incorporated into animal
feed.
ITQ32 Egg-shells may be ground up and used in animal feed. They provide
calcium.
11033 Animal wastes are ground up, milled, mixed with other ingredients and
formed into pellets.
11034 Biotechnology improves the production of animals for food by increasing
growth. It offers the possibility of producing human hormones and other
beneficial compounds in milk.
11035 The animals could be stressed by the treatment; they could show
abnormal behaviour; they could develop diseases and degenerative
conditions; there is 'wastage' of embryos.
Examination-style
questions
Multiple Choice Questions
1. Which statement is correct about the composition of goat's milk
compared with that of cow's milk?
A it has less phosphorus
B it has more vitamin B,
C it has larger fat globules
D it is less nutritious
2. The removal of the testicles of young male farm animals is called:
A disbudding
B docking
C castrating
D weaning
3. The feed ration given to pullets between week 7 and week 18 is called:
A starter
B grower
C layer
D finisher
4. The part of the male reproductive system that propels sperm into the
vagina of the cow is the:
A penis
B epididymis
C prostate gland
D vas deferens
5. Fertilisation in cattle occurs in the:
A ovary
B oviduct
C uterus
D infundibulum
Short answer and essay-type questions
6. Give an account of management techniques used in the care of the
young of a named farm animal. Include references to special feeding and
housing requirements.
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.Write an account of the role of biotechnology in animal production.
338
II II
IIIIIIIIIIIIIIIIIIInumumn..........
'III'll
School-based A ^ s E s s m E H t
SBA com
p
o HE Ht
Concept and importance
• The School-based Assessment (SBA) component contributes a maximum of 40%
of your total examination marks.
• The varied practical activities of the SBA should help you to acquire the
knowledge, skills and attitudes necessary for a better understanding and
appreciation of agriculture as a career or vocation.
• As you pursue your projects and participate in practical agricultural activities you
will:
— be taught how to use the various skills correctly
— be given the chance to practise the skills with guidance from your teacher
— improve your self-confidence, technique and competence
— demonstrate your high level of competence based on CSEC criteria
— complete and present your portfolios and research project (if applicable) to
your teacher for assessment.
The SBA requirements for Agricultural Science may be reviewed periodically
and changed by the Caribbean Examinations Council (CXC). At present the SBA
requirements for Single and for Double Award courses are as shown below.
SBA requirements
Single Award
(i)
Each student will be credited for his or her performance in TEN skills.
• FIVE skills will be drawn from Section B, Crop Production.
• FIVE skills will be drawn from Section C, Animal Production.
(See pages 46-48 of Syllabus CXC 07/G/SYLL 06 for details.)
(ii)
Each student will:
• cultivate and keep records of at least four vegetable crops: fruit, root, leaf
and flower
• rear a batch of 100 broilers, with record-keeping, each term
• develop a portfolio and do a cost analysis (profit and loss analysis) for each
crop cultivated and also for each batch of broilers reared
• submit a cost analysis of ONLY one crop and a cost analysis for ONLY one
batch of broilers for SBA assessment
• participate fully in other practical activities which are related to agriculture.
Students may work in groups or by themselves, but this must be decided and agreed
upon before the project begins. Each student must present his own individual report.
Note that cost analyses of only one crop and only one batch of broilers are to be
presented for the SBA requirement.
Double Award
(i)
Each student will be credited for his or her performance in TEN skills.
•
FIVE skills will be drawn from Section B, Crop Production and Section D,
•
Horticulture
FIVE skills will be drawn from Section C, Animal Production and Section E,
Animal Management.
(See pages 46-49 of Syllabus CXC 07/G/SYLL 06 for details.)
(ii) Each student will:
• cultivate and keep records of at least four vegetable crops: fruit, root, leaf
and flower
•
rear a batch of 100 broilers, with record-keeping, each term
•
rear a batch of 25 layers, with record-keeping, each term
•
develop a portfolio and do a cost analysis (profit and loss analysis) for each
crop cultivated, each batch of broilers and each batch of layers reared
•
submit a cost analysis for ONLY one crop cultivated, ONLY one batch of
broilers and ONLY one batch of layers for SBA assessment
•
do and submit an individual Research Project and Report on an agricultural
issue or problem for SBA assessment
•
participate fully in other practical activities which are related to agriculture.
Students may work in groups or by themselves, but this must be decided and agreed
upon before the project begins. Each student must present his own individual report.
Note that cost analyses of only one crop, only one batch of broilers and one batch
of layers are to be presented for the SBA requirement.
(iii) Students completing the Double Award course are required to do a Research
Project on a particular agricultural issue or problem. The material must be
submitted in the form of a report of approximately 1000-1500 words. The text
can be supplemented by, for example, graphs, figures, slides and photographs.
The report must show that you have applied appropriate experimental and data
handling techniques, and included your own results and recommendations based on
your research.
Description
i.
Research question
3 A short description of the project
with the objectives
ii.
An abstract
3 A precis of what was done
1
3 Results
1
3 Relevance to topic
1
3 Depth
1
3 Relevance to topic
1
3 Choice of method
1
iii. Literature review
iv. Research methodology
340
Marks
allotted
1
Item
Item
Description
v.
3 Accuracy
Results
vi. Data analysis
vii. Discussion
viii. Conclusion and recommendations
ix. Communication of information in a logical
manner using correct grammar
Marks
allotted
1
3 Depth
1
3 Statistical method
1
3 Relevance to project
3 Accuracy
1
1
3 Depth
1
3 Relevance to results
1
3 Depth
1
3 Relevance to discussion
1
3 Relevance to objectives
1
3 Relevance to objectives
3 Logical sequence
1
I
20
Total
Table I CXC criteria for marking the research project.
Assessment of skills
In the Assessment of skills, the teacher will observe:
• the student's dexterity (level of skill)
• the time taken for the completion of the skill in an assessment
• the confidence shown by the student, and
• the resourcefulness when handling any problems.
Item
Description
i.
3 Unsatisfactory
1
3 Satisfactory
2
3 Excellent
3
ii.
Technique
Competency
Total
Marks
allotted
3 Non-mastery
1
3 Limited competency
2
3 Mastery
Maximum possible
6
3
Table 2 Rating scale for assessment of practical skills.
Some guidelines for presenting your reports
Crop and Animal Production Projects
(i)
Keep your cost analyses in a soft-backed folder, quarto or A4 size. Present your
complete report in this folder.
(ii)
Write your name and registration number, the name of your school and Award
(single or double) on the outside of the folder and the first page of the report.
(iii)
Include a mark scheme for each cost-analysis report, showing your teacher's
assessment of the report. (See page 40 of Syllabus CXC 07/G/SYLL 06 for details.)
Note that your description of your activities counts for 6 out of the 20 marks
available, 4 in the Introduction and 2 in 'Language'.
341
Introduction
i.
Marks
allotted
Description
Item
3 Name of project
3 Location
3 Duration
Complete budget
ii.
I*
Actual income and
expenditure
3 Description of activities, sketch of layout of plot, materials
and equipment
3
3 Schedule of operations
1
3 Projected income (output x price)
1
3 Projected expenditure (itemised)
1
3 Surplus
1
3 Income (from sale of produce)
2
1Expenditure
2
I.
3 Surplus/deficit (shortfall)
1
iv. Analysis
3 Comparison of projected and actual income, expenditure
and surplus/deficit
2
3 General comments
2
3 Conclusion
1
3 Recommendations
1
13 Language
V Communication of information in a logical manner using
correct grammar
20
tal Alk
Table 3 Criteria for marking the cost-analysis.
Research Project
The Research Report must include the following, in the order given:
1. Title
3. Abstract
5. Methodology
7. Data analysis
9. Conclusion and recommendations
2. Table of contents
4. Literature review
6. Results
8. Discussion
10. Bibliography
(i)
Submit the report in a soft-backed folder.
(ii)
Write your name and registration number, the name of your school and the
title of your research project on the outside of the folder and the first page of
(iii)
the report.
Include a mark scheme at the end of the report which clearly shows your
teacher's assessment of the project.
(See page 42 of Syllabus CXC 07/G/SYLL 06 for details.)
You may obtain information from such sources as the internet, textbooks and
pamphlets but you must not copy material directly from any source.
You must acknowledge all such sources of information in the bibliography.
342
SELECTED PRACTICAL SKILLS
Section B: Crop Production (Single Award and
Double Award)
B3: Use techniques of fertiliser application
Technique 1: Side placement - drill fertiliser into the soil
Conditions:
• Type of crop: Ochro, 5 weeks old (direct seeding), about to blossom.
• Cropping system:
- Row crop: planted on the contour; two rows per bed.
- Plants: 60 cm in the row and 75 cm between rows.
• Climate: tropical; apply fertiliser on a sunny day during the rainy season.
• Topography: gently sloping land.
Materials:
Fertiliser (NPK 12:12:17); disposable gloves; rubber boots; plastic bucket; plastic
scoop; garden trowel; watering can with a rose; wheelbarrow.
Procedure:
1. Dress suitably for a field practical.
2. Ensure rubber boots and gloves are worn.
3. Place all necessary materials in the wheelbarrow
and take them to the field plot.
4. Using the plastic scoop, lift fertiliser from the bag
and place 1 kg into the plastic bucket.
5. Using the garden trowel, break up the crusted soil
12-15cm away from the base of the ochro plant at
the upper side of the slope, creating a small hole
5-7cm deep.
The fertiliser is trickled into the hole
near the ochro plant.
6. Place 15-20 g of the NPK 12:12:17 fertiliser in the
hole and cover over with soil.
7. Repeat the process until all ochro plants on the garden bed are fertilised.
8. Apply water to the soil, using the watering can with a rose.
Questions:
1. Why was NPK 12:12:17 fertiliser selected for the ochro crop?
2. Name another suitable fertiliser for an ochro crop.
3. Why was the fertiliser drilled into the soil?
4. Why was the fertiliser placed beside the plant at the upper end of the slope?
5. Why was water applied to the soil after fertilising the crop?
343
Technique 2: Ring placement - top dressing
Conditions:
•
Type of crop: Lettuce, transplanted 2 weeks ago.
•
Cropping system:
— Row crop: planted on a cambered bed, three rows per bed.
— Plants: 30 cm in the row and 30 cm between rows.
Materials:
Fertiliser: urea (46%N); disposable gloves; rubber boots; plastic bucket; plastic scoop;
garden trowel; watering can with rose; wheelbarrow.
Procedure:
1. Follow procedures 1 to 4, as listed in Technique 1.
2. Using the garden trowel, break up the crusted soil
lightly, 5-7 cm away from each lettuce plant, in a
circular manner.
3. Apply 10-15 g of urea as a top dressing in a ring,
5-7 cm away from each lettuce plant.
4. Water the plants and the soil using the watering
can with a rose.
Questions:
A ring of fertiliser is placed around the
lettuce plant.
1. Why was the crusted soil broken up with the
garden trowel?
2. Why was urea used for this particular crop?
3. Name two other fertilisers which are suitable for the lettuce crop.
4. Why was the fertiliser placed in a ring 5 cm away from each lettuce plant?
5. Why was a watering can with a rose used to irrigate the crop?
Technique 3: Band placement - top dressing
Conditions:
•
Type of crop: Maize: plants ready to tassel.
•
Cropping system:
— Row crop: planted on cambered beds.
— Plants: 30 cm in the row and 75 cm between rows.
Materials:
Fertiliser: NPK 13:13:20; disposable gloves; rubber
boots; plastic bucket; plastic scoop; straight cutlass;
garden hose with a nozzle.
Procedure:
1. Follow procedures 1-4, as listed in Technique 1.
The fertiliser is applied in a band
parallel to the maize plants. Then it is
watered in using the hose.
344
2. Using the straight cutlass break up the crusted soil lightly, 9-12 cm away from
the base of each plant, in a band but only on one side of each row of maize.
3. Apply NPK 13:13:20 fertiliser at the rate of 25-30 g/m 2 , in a band parallel to each
row of maize
4. Use the garden hose with a fine nozzle spray to irrigate the crop.
( Remember to tidy-up afterwards and to replace all materials in their respective
places.)
Questions:
1. Why was NPK 13:13:20 fertiliser selected for the maize crop?
2. Name another suitable fertiliser for this crop.
3. What fertiliser promotes rapid growth of maize plants?
4. Why was the crusted soil broken up before placement of the fertiliser?
5. Why was water applied to the soil after fertilising the crop?
B4: Use appropriate techniques in applying soil amendments
Technique 1: Applying dolomitic limestone to the soil
Conditions:
• Soil samples were taken from the school garden.
Laboratory tests were carried out on the samples.
The laboratory report recommended that the garden soil should be limed at the
rate of 500 kg/ha.
Materials:
Dolomitic limestone; shovel; rake; hoe; garden fork; rotovator.
Procedure:
1. Plough the garden bed and refine the soil to a
medium tilth.
2. Using the shovel, spread the dolomitic limestone
on to the refined soil at the rate of 0.5 kg/m2.
3. Use a hoe or a rake to spread the limestone more
evenly over the ploughed area.
4. Use a garden fork or rotovator to incorporate the
limestone into the soil.
Questions:
1. Name two other forms of liming materials.
2. State one advantage of applying dolomitic
limestone to the soil.
3. What is the main purpose of liming the soil?
4. Why is the limestone spread evenly and
incorporated into the soil?
5. Name two pieces of equipment suitable for
The limestone is mixed with the soil
using a fork.
incorporating limestone into the soil.
345
Technique 2: Applying pen manure to the soil
Materials:
Pen manure; wheelbarrow; shovel; rake; hoe; garden fork; rotovator; bucket.
Procedure:
1. Plough the garden bed and refine the soil to a
medium tilth.
2. Use the wheelbarrow to transport the pen
manure to the garden bed.
3. Using the shovel, spread the pen manure on to
the refined soil at the rate of 1 bucket (10 I) per
m
2
4. Use the rake or hoe to spread the pen manure
more evenly on to the ploughed area of land.
5. Use a garden fork or rotovator to incorporate the
The rotovator mixes the manure in
with the soil.
pen manure into the soil.
Questions:
1. Explain the meaning of 'soil amendments'.
2. Name three types of soil amendments.
3. Why is the pen manure spread evenly and incorporated into the soil?
4. State three major benefits of applying pen manure to the soil.
5. What major factors cause the rapid breakdown of pen manure in tropical soils?
B5: Use an 'A' frame (level) to establish contour lines
Conditions:
•
Topography: sloping land, covered with grass.
•
Area was brushcut prior to the proposed activity.
Materials:
' A' frame with plumb-bob; 12-15 sharp wooden stakes (45 cm long); hammer; rubber
boots; garden line.
Procedure:
1. Dress appropriately, ensuring that rubber boots
are worn.
2. Select a spot on the lower part of the slope for
starting the contour line.
3. Place a stake upright at the chosen spot and
hammer it firmly into the soil to a depth of
10-15 cm.
4. Holding the 'A' frame in an upright manner, place
one of its legs against the base of the partially
buried stake.
The plumb-bob should be
perpendicular to the mid-line marked
on the 'A' frame.
5. Swing the 'A' frame in a horizontal manner across the slope with the other leg
in contact with the ground, until the plumb-bob is perpendicular to the mid-line
marked on the cross-bar of the 'A' frame.
6. Place a stake beside the second leg of the 'A' frame and hammer it into the soil.
7. Lift the 'A' frame and use the second stake as the new starting point.
8. Continue the process until all the stakes are buried.
9. Use the garden line to connect points where the stakes are buried, thereby
establishing the contour line.
10.Other contour lines may be established higher up the slope.
Questions:
1. Explain the meaning of 'contour line'.
2. Describe the topography of the land where contour lines are usually established.
3. What are the main purposes of establishing contour lines?
4. Describe the major features of the 'A' frame.
5. State the major farming activities which the farmer may pursue after establishing
contour lines.
B7: Demonstrate land preparation techniques
(a) Land clearing
Materials/equipment:
Weed wacker; rake; hay-fork; wheelbarrow; rubber boots; goggles; cap or helmet.
Procedure:
1. Wear safety apparel (PPE: personal protective
equipment): including boots, goggles, helmet.
2. Remove obstacles, including stakes and trellis
materials, from the area to be cleared.
3. Operate the weed wacker, following safety
precautions.
4. Cut down the herbaceous vegetation with the
weed wacker.
5. Use the rake to heap up the cut grassy material,
Safety gear should always be worn
when operating the weed wacker.
6. Use the hay-fork and wheelbarrow to remove and
stack all grassy material in an area for composting.
Questions:
1. Name two other tools/equipment which may be used for land clearing.
2. What is the main purpose of clearing a plot of land?
3. State two safety practices which farmers should adopt when clearing the land.
4. What other use can be made of the cut, grassy material?
347
(b) Primary and secondary tillage
Materials/equipment:
Garden fork; hoe; rubber boots.
Procedure:
I. Wear rubber boots and adopt safety practices.
Primary tillage
2. Use the garden fork to dig up the land area that
was previously cleared.
3. Using 'foot-pressure', insert the prongs of the fork
into the soil to a depth of 10 to 15 cm.
4. Lift and invert each 'spit' of soil dug out.
5. Break up large clumps of soil with the prongs.
6. Repeat steps 3 to 5 until the cleared land area is
dug up (ploughed/forked).
Primary tillage (left) and secondary
tillage (right) will give your crop a
good chance of growing well.
Secondary tillage
7. Use the hoe to cut up the larger clumps of soil into smaller pieces.
8. Continue the process of cutting up with the hoe, until the soil is refined to a
medium or fine tilth.
Questions:
1. Name one motorised piece of equipment used for primary tillage.
2. Give the names of three other tools or pieces of equipment that are also used for
secondary tillage.
3. Explain the meaning of 'tilth'.
4. State three purposes of tillage.
(c) Drain formation
Materials/equipment:
Garden fork; spade; garden line; four sharp stakes (60 cm long); hammer.
Procedure:
1. Hammer the stakes, two at each end of the proposed box drain, 30 cm apart and
about 15 cm deep.
2. Attach the garden line firmly to the stakes, marking-off the area for the drain.
3. Using the line as a guide, cut deeply into the soil with the spade to mark out the drain.
4. Use the garden fork to dig out the soil, spit by spit from the marked area, thereby
creating the rough drain.
5. Following the garden line, cut the sides of the drain neatly and deeply with the spade.
6. Remove the loose soil from the drain with the spade.
7. Ensure that the drain is well graded for the removal of excess soil water.
8. Following steps 1 to 7, dig the other drains around the garden bed.
9. Ensure that the drainage network is linked to a main drain, removing excess
water from the garden area.
-n co-•
Use garden line and stakes to mark out the box drain.
Questions:
1. Name two types of drains commonly used by crop farmers.
2. State the main purpose of drainage in vegetable production.
3. Why is the garden line used in establishing a drain?
4. Why should the farmer ensure that the drain is dug with a good 'grade'?
(d) Ridges and furrows
Conditions:
• The land was previously cleared and ploughed.
• The soil has been rotovated to a medium tilth.
Materials/equipment:
Sharp stakes (1 m long); garden line; hoe; spade; hammer.
Procedure:
1. Insert 3-5 stakes, each 20-30 cm deep, firmly into
the soil and equidistant apart, along the length
and at each end of the proposed ridge.
2. Attach the garden line firmly to each stake, 20 to
45 cm above ground level, marking out the area
for the middle of the ridge.
3. Using the hoe, pull the refined soil from both sides
Soil is pulled up along the line shown
by the stakes to form a ridge.
of the garden line to form the ridge (20 to 30 cm high).
4. Use the spade to lift soil from the furrow on to the ridge and also to level off the
soil in the furrow.
5. Repeat steps 1 to 4 until all the proposed ridges and furrows are established.
Note that:
• Ridges may be established 45-90 cm apart and 20-45 cm high, to suit the
particular crop.
• The low-lying area between two ridges is called a 'furrow'.
349
Questions:
1. Name two crops which are usually planted on ridges.
2. State two advantages of using ridges for the cultivation of specific crops.
3. Explain the meaning of 'furrow'.
4. State the main function of the garden line and stakes in establishing ridges and
furrows.
B8: Clean and maintain simple tools
Conditions:
1. Some tools used in the school garden have become soiled.
2. Other tools are either dull or have damaged parts.
Materials/equipment:
Garden tools (hoe, cutlass, fork, rake); bench grinder; file; hammer; hoe-handle;
wedges; absorbent rags; motor-oil; goggles; water for washing the tools.
Procedure:
1. Wash the tools (hoe, cutlass, fork, rake) carefully, removing dirt and mud stains
from the handles and metal surfaces.
2. Dry each tool with an absorbent rag or in the sun.
3. Use the wedges to fix the hoe handle firmly on to the hoe.
4. Use the bench grinder or the file to sharpen dull tools, for example, cutlass, hoe.
5. Moisten an absorbent rag with motor-oil.
6. Apply oil, using the rag, to the metal surfaces of each tool.
7. Store the tools securely in a tool room, away from corrosive elements.
8. Take tools which need welding to a welding shop to be repaired.
9. Keep an inventory of tools.
Questions:
1. Why should the farmer clean and maintain his garden tools?
2. State four major procedures in maintaining tools.
3. Why is oil applied to the metal surfaces of tools?
4. Explain the meaning of an 'inventory' in relation to tools.
5. Name three garden tools which need to be sharpened regularly.
B9: Demonstrate plant propagation techniques
(a) Budding
Materials:
'Stock' plant in container (Rangpur lime); orange (Navel) budwood (called the
'scion'); budding tape (clear polythene strips); budding knife; secateurs.
Procedure:
1. Select an area on the 'stock' plant, 20-25 cm from the soil level in its container.
2. Make a T-shaped incision on the stock using the budding knife.
3. Lift bark away from the incised area, carefully, with the budding knife.
350
4. Cut out the 'scion' (only one bud) from the budwood.
5. Insert the 'scion' into the incised area of the stock plant.
6. Tape the 'scion' on to the stock, covering the bud and the entire incised area.
7. Partially break the stem of the stock plant, 15-20 cm above the budded area.
8. Unwrap the area exposing the bud after 7-10 days.
9. Using a pair of secateurs, cut top off the stock plant, 3-4 cm above the growing bud.
(See diagram on page 155.)
Questions:
1. Name two other plants which may be propagated by budding.
2. Explain the meaning of: (a) scion, and (b) stock plant.
3. Why is the top of the budded stock plant partially broken?
4. State two advantages of budding.
(b) Grafting
Materials:
Budding knife; secateurs; polythene tape or strips; stock plant in a container (Rose
mango); budwood or scion (Julie mango).
Procedure:
1. Select an area on stem of stock plant, 20-25 cm above the soil level in its
container.
2. Make the correct incision for a side graft in the Rose mango stock plant.
3. Prepare the Julie mango scion, consisting of terminal and axillary buds.
4. Insert the scion on to the stock plant and tape firmly, using a strip of polythene.
5. Partially break the stem of stock plant, 15-20 cm above the graft.
6. Using a pair of secateurs, cut off the top of the stock plant, 3-4 cm above the
successful graft.
(See diagram on page 156.)
Questions:
1. Name two other plants which may be propagated by grafting.
2. Differentiate between: (a) a scion in budding, and (b) a scion in grafting.
3. Explain the meaning of a 'cleft' graft.
4. State two advantages of producing grafted plants.
(c) Layering (air layering)
Materials:
Knife; twine; moist moss or coconut fibre; clear polythene sheet (20 cm by 15 cm);
paint brush; secateurs.
Procedure:
1. Select a stem on a croton plant and remove a few leaves from the area to be
layered about 35 cm from the tip of the stem.
351
2. Using the knife, cut or girdle the stem in two places, 3-4 cm apart, and
completely remove the bark from the area.
3. Apply rooting hormone (powder) to the upper end of the girdled area, using a
tiny paint brush.
4. Place a ball of moist moss or coconut fibre around the girdled area.
5. Place a sheet of clear polythene around the moss/coconut fibre.
6. Tie the lower and upper ends of the sheet firmly on to the stem with pieces of
twine.
7. Observe! Roots should appear beneath the clear polythene in 2 to 3 weeks.
8. Using secateurs, remove the layered plant from the parent plant for placement in
a pot.
Questions:
1. Name two types of layering.
2. Why is rooting hormone applied?
3. State the purpose of the clear polythene sheet.
4. Name two other plants that may be propagated by layering.
(d) Cuttings
Materials:
Stem cuttings (croton, hibiscus); leaf cuttings (Sanseveria spp., begonia); rooting
hormone; potting mixture or peat moss; cloth; knife; dibber; secateurs; scissors; pots
or black polythene bags (containers); water.
Procedure:
1. Select and cut stem and leaf cuttings early in the
morning when plant cells are turgid.
2. Place stem and leaf cuttings in water or wrap
them in a moist piece of cloth.
3. Fill container (pot/bag) with peat moss (potting
mixture) and water the soil.
4. Using a round stick (dibber), create a hole or
channel in the moistened potting soil for the
The leaf is inserted gently into a
planting hole made by a dibber.
cutting.
5. Use a knife, pair of scissors or secateurs to prepare (trim) the cutting (stem/leaf),
so it will remain upright and balanced in the potting soil.
6. Dip the base of the cutting into a container of rooting hormone; tap gently to
remove excess powder.
7. Place the cutting into the hole/channel and gently firm the moist potting soil
around it.
8. Water the soil lightly, then place the container in a cool area for rooting of the
cutting to take place.
Questions:
1. Why should cuttings be taken early in the morning?
2. Explain why portions of large leaves of a stem cutting are usually cut or
trimmed.
Fl
3. Why is a hole/channel created in the potting soil to receive the cutting?
4. Name two orchard plants that may be propagated by stem cuttings.
B1 0: Prepare seedboxes and seedbeds
(a) Prepare seedboxes
Materials:
Empty standard-sized seedbox: 35 cm x 25 cm x 7 cm; dry grass (straw or leaf-mould);
potting soil or peat moss (Promix); pressboard; water and watering-can with a rose.
Procedure:
ronulnrly snacerl cearlc
1. Gather materials and place them within easy
reach.
2. Place a layer of dry grass, straw or leaf-mould into
the seedbox to cover the slits (drainage holes) at
its base.
3. Fill the seedbox with potting soil or Promix to a
height of 1 cm from the top.
4. Use the pressboard to level off and to press the
potting soil gently.
Make sure that the soil is watered
before sowing.
5. Water the soil in the seedbox.
6. Use the seedbox to sow seeds.
Questions:
1. What is another name for a seedbox?
2. What are the main purposes of seedboxes?
3. Why is a layer of straw/dry grass placed on the base inside the seedbox?
4. Why is potting soil filled to a height of lcm from the top of the seedbox?
5. State the function of the pressboard.
(b) Prepare seedbeds
Materials:
Brushing cutlass; hand tractor or garden fork; rotovator; hoe; rake; spade; garden line;
stakes; pen manure; NPK (10:15:10) fertiliser; soil insecticide; fungicide; watering can
with a rose.
Procedure:
1. Using the brushing cutlass and rake, clear the land
area of all grass and bush.
2. Plough the area using a hand tractor with a
plough attachment or a garden fork.
3. Refine the soil to a very fine tilth using a
rotovator, hoe or rake.
4. Using the stakes, garden line, fork and spade, dig
box drains around the seedbed (measuring about
3 m long and 1 m wide).
5. Camber the seedbed, using the hoe and rake.
Raking the surface of the seedbed after
incorporating fertiliser will remove
unwanted clumps of organic matter.
353
6. Apply organic and inorganic fertiliser to the seedbed:
•
pen manure: 2 to 4 cm thick, and
•
NPK (10:15:10) fertiliser: about 30 g/m2.
7. Incorporate the fertiliser within the top 4 to 8 cm of soil in the seedbed, using the
fork or rotovator.
8. Use the rake the remove large pieces of organic matter and to level off the
surface of the cambered seedbed.
9. Spray the seedbed with a mixture of soil insecticide and fungicide, using the
watering can.
10.Use the seedbed to sow vegetable seeds.
Questions:
1. State the purpose of a seedbed.
2. Why should the soil in a seedbed be prepared to a very fine tilth?
3. Describe a 'cambered' seedbed.
4. Why should a seedbed be cambered?
5. State the purpose of incorporating fertiliser into the seedbed.
B11: Thin-out seedlings
Materials:
Nursery box with seedlings; prepared nursery box ready to receive seedlings; dibber;
watering can with a fine rose.
Procedure:
1. Water the seedlings to be thinned-out and the soil in the newly prepared nursery
box.
2. Using the dibber, make holes 5 cm apart in rows and between rows in the
prepared nursery box.
3. With thumb and index finger hold one leaf of a seedling and lift it off with the
dibber.
4. Place the seedling in the hole created in the prepared seed box and use the
dibber gently to firm the soil around it.
5. Repeat procedures 3 and 4 until the prepared seed box is filled with thinned-out
seedlings.
6. Water both the boxes with seedlings to be thinned-out and the box with the
newly thinned-out seedlings.
7. Protect the newly thinned-out seedlings from direct sunshine and rain.
(See diagram on page 162.)
Questions:
1. Why are seedlings thinned-out?
2. State the main functions of the dibber.
3. Why is the seed box containing seedlings to be thinned-out watered before and
after the thinning-out process?
4. Why is each seedling held by its leaf, and not its stem, as it is lifted off with the
dibber?
5. Why should newly thinned-out seedlings be protected from direct sunshine and
rain?
Section C: Animal Production (Single Award and
Double Award)
C3: Identify, collect and mount forage plants
Materials:
Cutlass; secateurs or scissors; binder or folder; sheets of paper (Quarto: A4 size);
newspaper; Scotch tape; weights (pile of books); forage plants.
Procedure.
1. Identify your forage plant, for example, pangola grass.
2. Obtain the common name and botanical name of the
forage plant.
3. Obtain a brief description of the plant.
4. Use a cutlass to dig out a plant (pangola grass).
5. Use secateurs to cut the forage plant into sections:
•
bottom portion of stem with roots (if possible);
•
middle portion of stem;
•
top portion of stem with leaves (trimmed, if too
long)
p
•
top portion of leaf: 10-15 cm long.
6. Place cut sections between sheets of newspaper,
ensuring sections are spread out and leaves are opened
and flattened.
7. Place a relatively heavy weight, such as a few books,
on the newspaper and allow the materials to dry over a
period of 5-7 days.
8. After drying, remove the forage materials for mounting.
9. Arrange and fix the sections on to a plain sheet of paper
( Quarto: A4 size), using strips of Scotch tape.
After drying, the forage plant
can be removed for mounting.
10.On the page opposite in the binder/folder, write:
• the common name and botanical name of the forage plant
• a brief description of the plant.
11.Repeat procedures 1-10 for other forage plants such as kudzu, elephant grass,
Guinea grass, para grass, molasses grass.
Questions:
1. Explain the meaning of 'forage' plants.
2. Why are the plant sections placed between newspaper and pressed with a heavy
weight?
3. Why should the common name and botanical name of the forage plant be clearly
stated?
4. Why should a brief description of the forage plant be placed beside the mounted
specimen?
5. State the importance of this practical project.
C4: Determine the space requirement for different batches of
broilers, layers
(a) Determine the space requirement for 75 broilers
Materials:
Measuring tape (25 m); poultry pen; movable barrier; farm notebook; pencil; ruler
(30 cm).
Procedure:
1. State the space requirement for one broiler:
•
30 cm by 30 cm = (0.30 cm) 2 or
•
0.3 m X 0.3 m = (0.3 m) 2 = 0.09 m2.
2. Calculate the space requirement for 75 broilers:
•
Space requirement for one broiler = 900 cm 2 = 0.09 m2
•
Space requirement for 75 broilers = 900 cm 2 x 75
= 67 500 cm 2 or 6.75 m2
3. Using the measuring tape, measure the width of the poultry pen:
•
Width of poultry pen = 300 cm or 3 m (for example).
4. Calculate the length of the poultry pen that is required for 75 broilers:
•
L x W (or B: Breadth)
Formula: Area
67 500 cm 2 (6.75 m 2 ) = L x 300 cm (3 m)
Length (L)
-
67 500 cm 2(6.75 m2)
or
300 cm
3m
225 cm or (2.25 m)
5. State the space requirement for 75 broilers, as calculated:
•
Space requirement for 75 broilers = 300 cm (3 m) x 225 cm (2.25 m)
= 67 500 cm 2 or (6.75 m2)
6. Measure the required width of the poultry pen and place the movable barrier at
the 2.25 m mark.
7. Using your notebook, ruler and pencil, draw and label the floor plan, showing
the space requirement for 75 broilers.
(b) Determine the space requirement for 40 layers
Materials:
Same as in C4 (a) above.
Procedure:
1. State the space requirement for one layer:
356
•
0.9 m by 0.9 m = 0.81 m 2 or
•
900 cm x 900 cm = 8100 cm2
2. Calculate the space requirement for 40 layers:
2
• Space requirement for one layer = 0.81 m or 8100 cm2
2
• Space requirement for 40 layers = 0.81 m x 40
= 32.4 m 2 or 324 000 cm2
3. Using the measuring tape, measure the width of the poultry pen:
• Width of poultry pen = 3 m or 300 cm (for example).
4. Calculate the length of the poultry pen that is required for 40 layers:
= L x W (or B; Breadth)
• Formula: Area
32.4 m 2 (324 000 cm 2 ) = L x 3 m (300 cm)
Length (L)
= 32.4 m2
3m
or
324 000 cm 2
300 cm
= 10.8 m or 1080 cm
5. State the space requirement for 40 layers, as calculated:
• Space requirement for 40 layers = 3 m (300 cm) x 10.8 m (1080 cm)
= 32.4 m 2 or 324 000 cm2
6. Measure the required width of the poultry pen and place a movable barrier at
the 10.8 m mark.
7. Using your notebook, ruler and pencil, draw and label the floor plan, showing
the space requirement for 40 layers.
Questions:
1. Differentiate between: (a) a broiler, and (b) a layer.
2. State the space requirement for (a) one broiler, and (b) one layer.
3. Explain why broilers are reared in a more confined space (area) than layers.
4. State the importance of drawing floor plans for batches of broilers and layers.
C5: Prepare a brooder for baby chicks
Materials:
Broom and other cleaning equipment; disinfectant; foot-bath; wood-shavings;
movable partitions; bottle-type waterers; feed-trays; infra-red bulb; feed-bag screens;
50 day-old baby chicks; newspaper.
Procedure:
1. Thoroughly sweep, clean and disinfect the poultry
pen 48-72 hours before the baby chicks are
brought into the brooder.
2. Use movable partitions to mark off an area 2 m by
2 m for the establishment of the brooder and to
confine the baby chicks.
3. Place wood-shavings on the floor of the brooding
area to a thickness of 5-7 cm.
4. Attach feed-bag screens on to the wire fence of
the brooder to keep out cold draughts.
5. From the ceiling, suspend an infra-red bulb with
a hover, so that heat is directed to a central area
within which the temperature is 32-33°C.
^u'G 1l NS, ti
The infra-red heater provides the
chicks with warmth that would have
been provided by the mother hen.
357
6. Place two feed-trays with broiler starter and two bottle-type waterers with clean
water, spacing them in the central area of the brooder.
7. Spread a sheet of newspaper on the wood-shavings on the first day when the
baby chicks are brought into the brooder.
8. Scatter some broiler starter on the newspaper to introduce feed to the baby
chicks.
9. Place a foot-bath at the entrance of the brooder.
Questions:
1. Explain the meaning of a 'brooder'.
2. State the purpose of the brooding process.
3. Why is feed scattered on newspaper on the first day when the baby chicks are
introduced into the brooder?
4. Why is an infra-red bulb placed in the brooder?
5. State the function of the wood-shavings on the floor of the brooder.
C6: Clean and disinfect pens
Materials:
Broom; hand brush; shovel; wheelbarrow; water-hose; watering can with fine rose;
animal pen (e.g. rabbitry); absorbent rag; concentrate ration and clean wilted herbage;
clean drinking water.
Procedure:
1. Remove and wash the animals' feeders and waterers.
2. Using a hand brush, remove any droppings and herbage from the floor and
corners of the hutches.
3. Dry the feeders with an absorbent rag and fill them with appropriate amounts of
concentrate ration, suited for the animals (rabbits in this example).
4. Provide fresh, clean, wilted herbage for the rabbits.
5. Refill the waterers with fresh, clean water and replace them in the hutches.
6. Sweep and shovel up the droppings and herbage from the concrete floor of the
rabbitry. Take to the manure heap using the wheelbarrow.
7. Thoroughly scrub and wash the concrete floor and lower areas of the walls and
corners of the rabbitry.
8. Use the watering can to spray a disinfectant mixture on to the floor, lower walls
and corners of the rabbitry.
9. Ensure that the area is well ventilated to enable the floor to dry out rapidly.
Questions:
1. Why should animal pens be cleaned and disinfected?
2. What is the major function of a disinfectant?
3. State the major steps in the process of cleaning a pen.
4. What use is made of the soiled herbage and droppings?
5. How often should the pens of animals be cleaned and disinfected?
r
C9: Collect, clean, sort, grade and pack table eggs
Materials:
Layer unit; table eggs; absorbent rag; water; egg crates; record sheets; egg baskets.
Procedure:
1. When collecting eggs from the layer unit, lift them
gently from the nest boxes.
2. Place the eggs carefully in the egg baskets and
then take them to the egg room.
3. Using a moistened rag, wipe each egg removing
dirt and bloody stains from the shell.
4. Sort the eggs according to: colour, normal,
abnormal, cracked and record the numbers on the
egg record sheet.
Dirty looking eggs will not sell well so
any stains should be removed.
5. Grade the normal eggs according to size: Jumbo,
Extra large, Large, Medium, Small and record the
numbers on the egg record sheet.
6. Pack the eggs, according to their grades, in egg crates.
7. Store the eggs in a cool room and market them promptly.
Questions:
1. Differentiate between (a) table eggs, and (b) hatching eggs.
2. Why should eggs be cleaned?
3. Why are eggs wiped with a moistened rag and not washed?
4. Why are eggs sorted and graded?
5. State the major grades of eggs.
C1 0: Determine the dressing percentage of broilers and rabbits
Materials:
Broilers and rabbits ready for slaughter; scale for weighing; tools/equipment for
slaughtering, plucking, skinning and gutting.
Procedure:
1. Weigh the rabbit/broiler to determine its liveweight in kilograms.
2. Record the liveweight of the rabbit/broiler.
3. Slaughter the rabbit/broiler.
4. Remove the offal: head, skin (rabbit), feathers (broiler), feet.
5. Weigh the dressed carcass of the rabbit/broiler.
6. Use the following formula to calculate the dressing percentage of the rabbit/
broiler:
Dressing percentage — Dressed carcass weight ( kg) x 100
1
Liveweight of animal (kg)
Questions:
1. Explain the meaning of 'offal'.
359
2. Distinguish between: (a) liveweight, and (b) dressed carcass weight.
3. State the formula for calculating the dressing percentage of an animal.
4. A buck rabbit weighing 6 kg produced a dressed carcass weight of 3.5 kg.
Calculate the dressing percentage of the rabbit.
5. How should offal be disposed of?
Section D: Horticulture (Double Award ONLY)
D15: Establish a fruit orchard
Conditions:
•
Land area has been cleared, tilled, graded and well drained.
•
Cambered beds, 40 cm wide, have been established.
Materials:
Fruit trees (Julie mango, guava, WI cherry, orange, grapefruit, coconut); measuring
tape; stakes; pen/compost manure; NPK (10:15:10) fertiliser; watering can; water;
garden trowel; spade.
Procedure:
1. Draw a field layout plan showing the cambered
beds and the proposed location of the various fruit
trees.
2. Following the recommendations of 6-8 m apart,
suited for each particular tree, measure out the
planting distances and place stakes where the fruit
plants are to be established.
3. Dig holes 45 cm x 45 cm x 45 cm where the
stakes are placed and incorporate one bucket of
pen/compost manure plus 25 g NPK (10:15:10)
into the soil which was dug out.
Each tree is planted at the centre of a
mound.
4. Refill the hole with the soil mixture and establish
a mound 20-25 cm high and 50-60 cm in
diameter.
5. Plant out the trees at the centre of each mound and avoid planting them too
deeply.
6. Using the watering can, apply water to the soil for the newly planted fruit trees.
Questions:
1. Explain the meaning of an 'orchard'.
2. Why should cambered beds be established for an orchard?
3. State the importance of 'appropriate planting distances' for the fruit plants.
4. Why should mounds be used for planting the fruit plants?
5. What are the recommended planting distances for:
(a) Julie mango (b) grapefruit (c) WI cherry (d) dwarf coconut?
D16: Select and establish planting materials for banana production
Conditions:
• Land area has been cleared, tilled, graded and well-drained.
• Cambered beds, 9 m wide, have been prepared.
• Planting materials to be obtained from a banana farmer.
Materials:
Selected planting materials; luchette; cutlass; knife;
soil insecticide (Diazinon); fungicide (Cupravit);
measuring tape; stake; spade; garden trowel; paper,
pencil and ruler.
Procedure:
(a) Select planting materials
1. Check the banana stools in the farmer's plot and
select planting materials in the following order of
priority:
(ii) maiden suckers
(i) sword suckers
(iii) bull-heads (corms of plants which have already
borne fruit)
2. Use the luchette to dig out the selected planting
materials.
3. Pare or clean the planting materials:
• cutting out diseased or worm-eaten areas of
Sword suckers and maiden suckers are
easy to tell apart.
the banana corms
• trimming off the tops of maiden suckers, 30-45 cm above the corms
• cutting bull-heads into 2 to 4 pieces, depending on the number of visible
'peepers' (shoots).
4. Immerse the pared corms in a soil insecticide (Diazinon) and fungicide (Cupravit)
mixture, for 15-20 minutes.
(b) Establish planting materials
1. Draw a field layout plan, showing the cambered beds and location of the
proposed planting system.
2. Measure and stake out the planting distances for the selected banana plants:
• 3 rows per bed;
• 2 m in the row, and
• 3 m between rows.
3. Dig holes, 45 cm x 45 cm x 45 cm, incorporating the topsoil and subsoil, and
establish mounds 10-15 cm high and 50-60 cm in diameter.
4. Plant the selected planting materials at the centre of each mound.
Questions:
1. Explain the meaning of: (a) sword sucker, (b) maiden sucker, (c) bull-head.
2. Which is the best planting material for establishing a banana plot?
361
3. Why are banana planting materials pared and immersed in an insecticidal/
fungicidal mixture?
4. State the recommended planting distances for banana plants.
5. State the importance of a field layout plan for banana production.
D1 8: Harvest the flowers of ornamental plants
Materials:
Secateurs; plastic bucket with water; plots of ginger lilies and anthuriums in bloom.
Procedure:
(a) Harvest anthuriums
1
Select anthurium flowers in which the spadix is fully opened and harvest them
early in the morning.
2. Using sanitised secateurs, cut the flower stalk (peduncle) 20 to 45 cm long or
longer, depending on the variety of anthurium.
3. Place the flowers upright with their cut ends in a bucket, one-third filled with
fresh, cool water.
4. After harvesting, take the bucket to a cool room for post-harvest treatment for
the market.
(b) Harvest ginger lilies
1. Harvest the lilies very early in the morning when the plant cells are turgid.
2. Select blooms in which 75% of the floral bracts are fully opened or developed.
3. Using sanitised secateurs, cut each ginger lily to 60-90 cm long with the
peduncle and a few leaves attached.
4. Place the flowers upright with the cut ends in a bucket, one-third filled with
fresh, cool water.
5. After harvesting, take the bucket to a cool room for post-harvest treatment for
the market.
Questions:
1. Why should flowers be harvested early in the morning?
2. At what stage of maturity should anthuriums and ginger lilies be harvested?
3. State the length at which anthurium and ginger lily peduncles should be cut.
4. Why are the cut flowers placed in a bucket with fresh, cool water?
5. Why should sanitised secateurs be used to harvest the flowers?
D20: Establish a lawn or turf area
Materials:
Garden fork; hoe; rake; pen manure; NPK (10:15:10) fertiliser; clumps of zoysia grass;
garden trowel; water hose with nozzle; water.
Procedure:
LA
1. Clear the land area, then plough (fork) and refine
the soil to a fine tilth.
2. Using the hoe and rake, grade the soil surface for
drainage.
,_-__--
3. Incorporate manure into the soil:
z
/
•
pen manure: 2 buckets per m
•
NPK (10:15:10) fertiliser: 25 g per m 2 .
/ .,
4. Level off the soil surface and remove large pieces
^, ^
^^,.yR;^^7y
.:
;^
..
M1
•..
•Y
of organic matter with the rake.
5. Apply a soil insecticide (Diazinon) and fungicide
( Cupravit) mixture to the prepared area before
Take care when watering that the grass
clumps are not dislodged by the water.
planting.
6. Plant out clumps of zoysia grass, 20-30 cm apart, using the trowel.
7. Apply water, using the hose and nozzle, to settle soil around the newly planted
clumps of lawn grass.
Questions:
1. Name three types of grasses which may be used for the establishment of a lawn.
2. Why is the soil prepared with a fine tilth?
3. Name the planting materials which may be used for establishing a lawn or turf.
4. Why is manure incorporated into the soil before planting?
5. Name two fertilisers which may be used to promote the luxuriant growth of
lawn grass.
D22: Mow a lawn or turf area
Materials:
Lawn mower, weed wacker, lawn rake, feed bag, safety gear.
Procedure:
1. Check the lawn or turf area and remove any obstacles
including stones, plastic bottles and cans.
2. Start the lawn mower following the recommended
procedure.
3. Operate the mower, following safety practices, and
mow the lawn area, strip by strip: push forward or pull
backwards, as the surface permits.
4. Continue until the entire area is mowed, then switch
off the lawn mower.
5. Wear safety gear including goggles, rubber boots,
gloves and a helmet.
Following safety precautions, operate the weed wacker
and cut the grass around the edges and corners.
6. Use the lawn rake and feed bag to heap and remove
the mowed grass to an area for composting or for
mulching ornamental plants.
The mowed grass can be used to
make compost.
363
7. Wash the lawn mower and other pieces of equipment and adopt the
recommended maintenance procedure.
Questions:
1. Why should obstacles and mobile objects be removed before mowing a lawn?
2. State the importance of using safety gear.
3. Why should safety precautions and procedures be followed when operating a
lawn mower and weed wacker?
4. Name other pieces of equipment that may be used to cut the lawn grass around
the edges and corners.
5. For what purposes can the lawn trimmings be used?
Section E: Animal Management (Double Award ONLY)
E1 4: Prepare accommodation for mother and young animals
(a) Prepare accommodation for a doe rabbit and kittens
Materials:
Hutch: 120-150 cm long, 60-75 cm wide, 40-45 cm high; nest box: 45-60 cm long,
35-45 cm wide, 15-25 cm high; disinfectant; feeder; waterer; dry grass; concentrates;
water; wilted herbage.
Procedure:
1. Identify a cool, quiet corner area of the rabbitry,
protected from predators and the elements.
2. Place a community hutch, together with a nest
box, in the chosen area.
3. Clean, wash and disinfect the area, the hutch and
the nest box, thoroughly.
4. Place some dry grass (bedding material) in the
nest box for the kittens. The doe rabbit normally
pulls off fur from her body and creates a bedding
for her kittens.
5. About 5-6 days before kindling, place the doe in
the prepared hutch.
6. Provide the following for the doe:
• waterer: with fresh, cool water
The bedding for the baby rabbits is
dried grass.
•
feeder: with concentrates (rabbit ration)
•
wilted herbage: kudzu, railway daisy or sweet potato vines.
Questions:
1. Explain the meaning of: (a) rabbitry, (b) hutch, (c) kittens.
2. What is the gestation period of a pregnant doe rabbit?
3. State the purpose of a nest box in rabbit rearing.
4. What name is given to the act of giving birth in rabbits?
5. State the recommended dimensions of a hutch, suitable for a doe and her kittens.
(b) Prepare accommodation for a sow and piglets
Materials:
Farrowing pen; bedding material; feed (lactation ration); water; broom; scrubbing
brush; disinfectant; infra-red lamp; fresh water and a lactation ration.
Procedure:
1. Check that the farrowing pen is secure and has
proper guard rails to protect the piglets from being
crushed by the sow (mother).
2. Clean, wash and disinfect the farrowing pen,
including the creep feeding area for the piglets,
thoroughly.
3. Place bedding material for the sow and piglets.
4. 5-7 days before farrowing, bathe the pregnant
sow, brushing its coat with a scrubbing brush
dipped in a disinfectant mixture, and then place it
The bars of the farrowing pen have
guard rails to prevent the piglets being
crushed.
in the sanitised farrowing pen.
5. Provide fresh, cool water and a lactation ration for the sow.
6. Place an infra-red lamp (bulb) in the creep feeding area to provide warmth for
the piglets.
Questions:
1. Explain the meaning of: (a) farrowing pen, and (b) creep feeding area.
2. State the function of the guard rails.
3. Why should an infra-red lamp be provided in the creep feeding area?
4. What is the gestation period of a pregnant sow or gilt?
5. State the importance of bathing the sow and disinfecting the farrowing pen.
El 5: Attend to young animals
(a) Inoculate baby chicks
Materials:
Baby chicks (50); vaccine (Newcastle/infectious bronchitis); bottle dropper; brooder;
two cardboard boxes.
Procedure:
1. Prepare the vaccine (liquid mixture) in the bottle
dropper.
2. Place all baby chicks in one cardboard box.
3. Lift and hold a baby chick gently, then place only
one drop of the vaccine in only one eye of the
chick.
4. Following inoculation, place each chick in another
cardboard box.
5. Continue the process until all chicks are
inoculated, and then release them in the brooder.
Ensure that one drop only goes into
the eye.
365
Questions:
1. Explain the meaning of: (a) vaccine, (b) inoculate.
2. Why should baby chicks be inoculated against prevalent diseases?
3. State three methods by which young animals may be inoculated.
4. Name three poultry diseases against which baby chicks are inoculated.
(b) Debeak chicks
Materials:
Baby chicks (one week old); electrical debeaker (hot iron); two cardboard boxes;
brooder.
Procedure:
1. Plug in the electrical debeaker and ensure it is hot.
2. Place all the baby chicks in one cardboard box.
3. Lift and hold a baby chick gently, with its beak
( mouth) opened.
4. Carefully burn off about one-third of the upper
beak only.
5. Following debeaking, place each chick in another
cardboard box.
6. Continue the process until all chicks are debeaked;
then release them into the brooder.
The electrical debeaker burns off a
portion of the beak.
Questions:
1. What is a debeaker?
2. Why are chicks debeaked?
3. Explain the meaning of 'cauterization' in relation to debeaking.
4. What may result if a very large portion of the bird's beak is removed (burnt off)?
E16: Apply first aid procedures in animals
(a) Treat a wound
Materials:
Antiseptic solution; swab (absorbent gauze); plaster, lint (bandage); synthetic rubber
gloves; pair of scissors; animal with a wound; soap; towel.
Procedure:
1. Wash hands with soap, dry with a clean towel, then put on rubber gloves.
2. Carefully trim hair/fur from around the wound.
3. Wash or clean the wound, using a mild antiseptic solution.
4. If the wound is small and shallow:
•
dry the wound with a swab (absorbent gauze)
•
bring the cut edges together and cover the wound with a plaster
•
bandage the wound with lint, if the area permits.
5. If the wound is long and deep, requiring stitches:
•
apply direct pressure with a clean gauze to control bleeding
•
call the veterinarian.
6. If the wound displays a cut blood vessel with steady bleeding:
• apply a tourniquet above the wound, if the area permits
• apply direct pressure with a clean gauze to control bleeding
• call the veterinarian.
(b) Treat an abscess
Materials:
Antiseptic solution; swab; warm water; scalpel or razor blade; plaster; lint (bandage);
synthetic rubber gloves; soap; towel; animal with an abscess.
Procedure:
1. Wash hands with soap, dry with a clean towel, then wear rubber gloves.
2. Gently touch the abscess and ensure it has softened sufficiently with the
application of a swab, soaked in warm water, over the past 2-5 days.
3. Use a scalpel or a clean, razor blade and cut open the abscess.
4. Squeeze out the pus.
5. Clean the area with an antiseptic solution.
6. Place a clean piece of lint over the area.
7. Apply a plaster to hold the lint in place.
8. Place a bandage over the area, if possible.
0
scissors
scalpel
O
gauze
plaster
li nt
A first aid box should contain certain items.
Questions:
1. Explain the meaning of: (a) first aid, (b) a tourniquet, (c) an abscess.
2. State the purpose of using an antiseptic solution to clean a wound or an abscess.
3. Why is a wound or abscess treated and covered with a plaster or bandage?
4. State the function of the following first aid materials: (a) swab, (b) scalpel,
(c) scissors.
State
the importance of treating injured or sick animals humanely.
5.
367
E17: Maintain animals and their surroundings in a hygienic condition
Materials:
Wheelbarrow; broom; brush; water hose; shovel; rake; weed wacker; disinfectant;
pesticides (insecticide, fungicide, rodenticide); slurry pit; animal pens: rabbits, goats,
sheep, broilers, layers; foot-baths.
Procedure:
1. Remove droppings and soiled bedding from the pens of rabbits, goats and sheep.
2. Place droppings in a manure heap, some distance away from the pens, to
decompose.
3. Thoroughly sweep, clean, wash and disinfect the pens daily.
4. Collect effluent from the pens in a slurry pit and use the liquid manure for the
cultivation of crops, including forage.
5. Bathe sheep and goats regularly, brushing their coats and ensuring that their feet
and hooves are kept clean, at all times.
6. Stir the deep litter regularly, incorporating the surface droppings, in the pens of
broilers and layers.
7. Clean the feeders and waterers of animals daily and top them up with fresh feed
and water.
8. Sweep, clean, wash and disinfect the eaves and drains around the pens of
animals, including cracks and crevices.
9. Using a weed wacker, cut down grass and bush from around the pens and tidy
the area.
10.Use pesticides to control mites, ticks, cockroaches, weevils, rats and fungal attack.
11.Put down foot-baths and use them.
12.Treat or cull sick/diseased animals. Incinerate or bury any carcass, following the
correct procedure.
Questions:
1. Explain the meaning of: (a) deep litter, (b) slurry pit, (c) foot-bath, (d) cull.
2. Name practices which should be followed to keep animals and their surroundings
in a hygienic state.
3. Why should a manure heap be placed some distance away from the pen?
4. What might occur if the feet and hooves of sheep and goats are not washed
regularly and kept clean?
5. State some benefits of keeping animals and their surroundings in a hygienic
condition.
E18: Administer control measures against internal and external
parasites
(a) Control internal parasites: intestinal worms, liver fluke, tape worm
Technique 1: Use medicated feed
Materials:
Farm animals: poultry, pigs, sheep, calves; medicated feed containing worm medicines.
or
i
Procedure:
1. Purchase appropriate medicated feed for the
particular farm animals.
do
2. Provide medicated feed for the farm animals for
the recommended period: 2-3 days.
3. Repeat the process at regular intervals: every 2-3
months.
Technique 2: Drenching farm animals
Materials:
Worm medicine (helminthic medicine); bottle; farm
animals: calves, sheep.
Procedure:
1
Purchase appropriate worm medicine for the
particular farm animal.
2
Measure and use the correct dosage, as
recommended.
3. Place the worm medicine mixture in a bottle.
4. With assistance, restrain the animal.
The animal must be restrained as
will not want to drink the medicine
5. Drench the animal: that is, place the mixture in
the animal's mouth, forcing it to swallow the medicine.
Technique 3: Spray pastures to destroy snails and the eggs of intestinal worms
Materials:
Sprayer, insecticide (e.g. Diazinon).
Procedure:
1. Wear protective gear.
2. Mix and fill sprayer with the insecticidal mixture, following the correct
procedure and recommendations.
3. Spray pastures, especially those paddocks recently grazed by adult farm animals
(cattle, sheep) on a regular basis.
(b) Control external parasites: ticks, lice, mites, fleas
Technique 1: Spraying farm animals
Materials:
Sprayer (manual); automated sprayers (spray races); insecticide (Sevin, Malathion);
water; protective gear; cows/calves.
Procedure:
1. Wear protective gear.
2. Following the recommendations, mix and fill the manual sprayer with the
insecticidal mixture.
3. Spray mixture on to the coat of each cow/calf, especially in areas where parasites
usually hide, such as the ears, flanks, tail and fore-legs.
369
4. Use an automated device (spray race) to spray animals on a large farm, as they
walk singly through a narrow channel.
Technique 2: Dipping animals
Materials:
Concreted pit/pond (for cattle); tub (for chickens); insecticide (Sevin, Malathion);
water; cattle, chickens; protective gear.
Procedure:
1. Wear protective gear.
2. Prepare the insecticidal mixture in the pit/pond or tub.
3. Dip each lice-infested chicken in the tub containing the insecticidal mixture.
4. Allow each cow/calf to walk through the pit/pond, becoming completely wet
with the insecticidal mixture.
Technique 3: Dusting animals
Materials:
Sevin powder; duster; protective gear; farm animals: chickens, calves.
Procedure:
1. Wear protective gear.
2. Place Sevin powder in the duster (dusting equipment) and ensure it is
operational.
3. Apply Sevin powder, using the duster, to the coats of calves and through the
feathers in chickens.
1. Spraying a cow with
insecticide.
2. Cattle going through
a dip.
3. Dusting cattle with
Sevin powder.
Some methods of controlling external parasites.
Technique 4: Pasture management
Materials:
Insecticides (Sevin, Malathion); sprayer; cows, calves.
370
4. Spraying pasture with
insecticide.
Procedure:
1. Practise rotational grazing of pastures, allowing the calves to graze, followed by
milking cows, then followed by dry cows.
2. Spray pastures when they are rested to control ticks and mites.
Technique 5: Environmental sanitation
Materials:
Cleaning equipment; disinfectant; insecticides, fungicides; protective gear; foot-baths
and wheel-baths.
Procedure:
1. Thoroughly sweep, clean, wash and disinfect the pens of animals, including the
eaves, drains and surrounding areas.
2. Spray the animal housing, especially areas with cracks and crevices: these are
good hiding places for parasites.
3. Dispose of droppings and soiled bedding material in well-managed manure
heaps, located some distance from animal pens.
4. Use foot-baths and wheel-baths on the farm.
Questions:
1. Differentiate between: (a) endoparasites, and (b) ectoparasites.
2. Name three examples of each of the following, in relation to farm animals:
(a) internal parasites, (b) external parasites
3. State three techniques for controlling internal parasites in animals.
4. Explain the meaning of:
(a) helminthic medicine,
(b) spray race,
(c) foot-bath.
371
Answers to multiple choice questions
Chapter 1
1 - C, 2 - B, 3 - A, 4 - B
Chapter 2
1 - B, 2 - C, 3 - B, 4 - C, 5 - C
Chapter 3
1 - C, 2 -B, 3 - D, 4 -A
Chapter 12
1 -C,2-A, 3 - D, 4 - C, 5 - A, 6 - B,
7 - C, 8 - A
Chapter 13
1 - B, 2- A, 3- D
Chapter4
Chapter 14
1 - D, 2 - B, 3 - C, 4 - C
I - C, 2 - A, 3 - B, 4 - D, 5 - C, 6 -- A
Chapter 15
Chapter 5
1 - C, 2 - B, 3 - D, 4 - A
1 - B, 2 - D, 3 - A, 4 - B, 5 - B
Chapter 6
1 - B, 2 - D, 3 - B, 4 - D, 5 - C
Chapter 7
1 - B, 2 - D, 3 - C, 4 - A, 5 - C
Chapter 16
1 - C, 2 - B, 3 - C, 4 - A
Chapter 17
1 - B, 2 - B, 3 - D, 4 - C
Chapter 18
1 - C, 2 - A, 3 - B, 4 - D, 5 - C, 6 - D
Chapter 8
1 - C, 2 - B, 3 - D, 4 - B, 5 - C, 6 - C, 7 - Chapter 19
B, 8 - D, 9 - D, 10 - A
1 - B, 2 - A, 3 - C, 4 - D, 5 - C, 6 - A, 7 - D
Chapter 9
1 - C, 2 - A, 3 - D, 4 - B
Chapter 20
1 - D, 2 - B, 3 - A, 4 - C, 5 - B
Chapter 10
Chapter 21
1 - C, 2 - D, 3 - A, 4 - D, 5 - A, 6 - C, 7 1 - C, 2 - B, 3 - A, 4 - A, 5 - B
- D, 8 - B
Chapter 11
1 - D, 2 - B, 3 - C, 4 - A, 5 - A
Chapter 22
1 - B, 2 - C, 3 - B, 4 - A, 5 - B
Index
Note: Alphabetical arrangement is word-by-word (ignoring 'in', 'and', 'the', etc.), so that, for example, 'rain shadow' comes
before 'rainfall'. Numbers in bold refer to pages where a topic appears only in an illustration rather than in the text. Page
numbers not in bold will often, of course, refer to pages that include diagrams as well as text. To use the index, always start by
looking up the most specific term for the topic you are interested in. Where more than one page reference is given, the bold
number indicates the more detailed reference.
'A' frame 117, 346-7
A horizon 95
abattoir 306, 333
abomasum 228, 229, 230
abscess treatment 367
absorption 226
acarine mites 294
acid rain 24
acid soils 103, 112
actinomycetes 104
active transport 166
adenosine triphosphate (ATP)
165
administrators 6
adsorption 97, 165-6
adventitious roots 147, 154
aerial roots 147
aesthetics, and consumers 44
African, Caribbean and Pacific
(ACP) countries 64-5
African star grass 245
afterbirth 325
ageing, meat 306
aggregates 99-100
agricultural development
institutions for 7-12
national and regional plans 3
Agricultural Development Bank
(ADB) 70, 72
Agricultural Engineering Division
8
agricultural engineers 4, 5
agricultural enterprise 42
agricultural land
fallow 191
loss of 19, 45
see also land
agricultural plans 3
agricultural production
and climate 126
factors in 45-7
hunger and poverty 23
see also animal production;
crop production; food
production
agricultural run-off 24
Agricultural Services Division 8
agriculture, definition 2
agro-forestry 108, 117
agro-processing 5
air
air layering 155
air pollution 24
soil air 96, 98
albumen 232
algae 24, 25, 104, 199
algal bloom 199, 258
alien pests and diseases 203
alimentary canal 226-7
alkaline soils 103
alleles 177-9, 266, 268
American foulbrood 293
ammonium compounds 105, 106
animal feed additives 33, 302,
368-9
animal feeds
from animal waste 334-5
balanced ration 238-9
importance of forages 244-7
local materials 238
nutrients in 236-8
rations for livestock 239, 244
animal health 289-90
GAPs relating to 26
animal production 355-60
biotechnology role in 335
breeding systems 267-8
GAPs relating to 26
genetic engineering in 278-9,
335
value-added products 333-5
Animal Production and Health
Division 8
animal reproduction 272-4
animal waste see manure
animals see farm animals
anions 103
annuals 145
antelope grass 245
anthers 151
anthrax 22
anthurium 211-12, 315, 316
anus 229
aphids 194, 195
apiculture 256, 291
aquaculture 257-9
artificial brooding 286-8
artificial incubation 275-6
artificial insemination 270-1, 276
asexual reproduction 152-7, 176
assets 46, 47, 84, 85
associate degree courses 10
average cost 48
average output 49
average product curve 50
avocado 313-14
B horizon 95
back-cross 179, 268
bacon 331
bacteria 104
causing bee diseases 293
crop diseases from 195, 196
for disease-resistant plants
181-2
nitrifying and denitrifying 106
nitrogen-fixing 105-6
see also microorganisms
balance sheet 84-5
balanced ration 238-9
bananas 211, 314, 361-2
band placement 344-5
battery systems 255
beak 227
bedrock 92
beds, making 134
beef 303, 332
beer-making 221
bees 256-7, 291-6
beeswax 295
biennials 145
bile 230
bio-terrorism 22-3
biodiversity 21, 35
biogas 304, 335
biological control
pests 33, 37, 197-8
weeds 193
biological weathering 93
biotechnology 181-2, 335
biotics 107
bird flu 291
birth 274, 325
blanching 217-18
bloat 291
bodi beans 210
boluses 230
bonemeal 110
boron 109
botanic gardens 311
Brassicas 180, 203
breeding systems
animal production 267-8
genetic improvement 269-70
see also cross-breeding; selective
breeding
breeds 264-5, 266, 267, 324
broilers see poultry
brood box 257
brooder 287, 357-8
brooding 286-8, 357-8
brushcutter 132, 137
budding 155, 157, 350-1
budgeting 87-8
budgets 71, 86-7
buffalypso 264, 329
bulbs 153, 157
burning vegetation 116, 191
by-products 238, 301-4, 334
C horizon 95
caecum 227, 229, 231
calcium 102, 237
calving cycle 329
cambered beds 134
cambium tissue 148
Canadian International
Development Agency
(CIDA) 12
candling 276
cannibalism 289
canning 218
capillary water 97
capital
definition 46, 69
fixed and working 47, 69
free movement of 63
production factor 45, 46-7
sources of 70-2
capital goods 43
carbohydrates 236
carbon cycle 104-5
carbon dioxide
in the carbon cycle 104-5
in photosynthesis and
respiration 164
weathering due to 93
carcass
dressed 302, 305
quality and weight 302, 332
career opportunities 3-6
Caribbean
botanic gardens 311
climate 16, 126
convergence zones 130
farm animal breeds 264
institutions for agricultural
development 7-12
local and regional challenges
16-21
natural hazards 24
plants grown in 312
sources of capital 70
volcanic eruptions 25, 94
weather fronts 130
Caribbean Agricultural Research
and Development Institute
(CARDI) 10
Caribbean Community
(CARICOM) 9, 62, 63
373
Index
Caribbean Confederation of
Credit Unions 47
Caribbean Development Bank
(CDB) 9, 46
Caribbean Disaster Emergency
Response Agency (CDERA)
20
Caribbean Examination Council
(CXC) Agricultural Science
qualifications 4, 6
Caribbean Food and Nutrition
Institute (CFNI) 9
Caribbean Single Market and
Economy (CSME) 62-3
carpels 151
cash 69
casual labour 45-6
cations 103
cattle
breeds 264, 265, 266, 267, 269
embryo transfer 270, 276-7
meat cuts 303
rearing 327-9
reproduction 272, 273
cell division 175-7
cell membrane 165, 175
cell wall 175
cells 175
cellulose, digestion 228, 231
centromere 176, 177
Centrosema 246
cereal crops
selection and hybridisation 181
see also maize
certification 6, 38
sanitary and phyto-sanitary 20
cervix 324
characteristics 177
inheritance 178-80, 267, 268
chemical treatment records 83-4
chemical weathering 93
chemicals
in the environment 198-200
hazardous 108
safety precautions 140
see also fertilisers; herbicides;
pesticides
chewing 226, 228, 229, 230
chicks, care of 286-8
chisel plough 137
chlorophyll 149, 167
chloroplasts 149, 175
chromatids 176, 177, 178
chromosomes 175, 176-8
chyme 230
citrus 312-13
clay 97, 98, 99, 103
clearing, land 116, 131-2, 347-8
climate 16, 45
and agricultural production
126
and harvesting 210
and soil fertility 106-7
see also rainfall; temperature;
weather; wind
cloaca 227
clones 156, 277-8
374
cloud cover 129
co-operatives 46, 70, 72-4, 334
coat colour 266
coccidiosis 290, 291
cocoa 221
coffee 222
cold front 130
collateral 71
College of Agriculture, Science
and Education (CASE) 10
colon 229, 230
colostrum 274, 327
combine harvesters 135, 211
commercial banks 46, 70
commercial services 43
commodity co-operatives 73
compost 36, 108, 110, 113-14
compound fertilisers 109-10, 111
compound leaves 148
Comprehensive Disaster
Management (CDM)
strategy 20
concentrates 239
consumable goods 43
consumer co-operatives 73
consumers (animals) 104
consumers (people) 43-4
consumption 43-4
contact herbicides 192
contact pesticides 197
container systems, sowing seeds
159-60
continuous grazing 242, 244
Contonou Agreement 64-5
contour cropping 117, 188
contour ploughing 117
convergence zones 130
cooking 218
cooling, food 330
copper 109
coprophagy 231
coral bleaching 25
coral reef destruction 25
corms 153
cortex 147, 148
costs 46, 48
and income 85-6
cotyledons 150, 158, 159
cover cropping 117, 189, 193
cows see cattle
crawler tractor 136, 137
credit supervision 72
credit unions 46-7, 70
credit-worthiness 71
credits 87
cricket 194
Critical Control Points (CCPs) 27
critical limits 27
crop diseases 195-6
management 197-8, 201, 202,
203
from pests 193-4
crop (in poultry) 226, 227
crop production 343-55
asexual reproduction 156-7
cultural practices 189-90
machinery used 135-7, 211
micronutrient importance to
108-9
records for 83, 200
sexual reproduction 156
crop residues 36
crop rotation 36, 188, 191, 197
crop sprayer 137, 138-9
cropping systems 112, 187-9
crops
animal feed from 238
cultivation see cultivation
diminishing returns 51
disease management in 197-8,
201, 202, 203
fertiliser requirements see
fertilisers
harvesting see harvesting
from market gardens 35
post-harvest handling see postharvest handling
processing 217
rainfall effect on 126
weeds' effects on 190-1
yield 83, 181, 198
see also horticultural plants;
ornamentals; plants; seeds
cross-breeding 264, 266, 267
advantages of 268-9
cross-pollination 151-2, 291
crosses 179, 181
crossing-over 178
cud 228
cultivars 267
cultivation
horticultural plants 312-16
vegetable crops 200-3
cultural practices
in crop production 189-90
horticultural plants 314
pest control 197
for soil conservation 116
vegetable crops 201, 202, 203
weed control 191-2
curing, food 331
cuticle 149
cuttings 154, 352-3
cytoplasm 175
'damping off' 163
daughter cells 176, 177
day-neutral plants 167
DDT 199
debeaking 288, 289, 366
debits 87
decision-making 43-4, 87
decomposers 104
decomposition 105
deep litter systems 254
deferred grazing 242, 244
deforestation 25
degree level qualifications 4, 6, 9,
10, 311
dehydration 219
demand 51-2, 55
democratic control 72
denitrifying bacteria 106
density, planting 193
depreciation 46, 69
Desmodium 246
diamondback moth 194
dicots 145-6, 147, 148, 149, 150
diet see animal feeds; feeding;
food
diffusion 165
digestion 226, 229-30, 231
digestive system
non-ruminants 228, 229
poultry 226-7
ruminants 228, 229
diminishing returns, law of 47-51
diploid number 176
diplomas 10
dipping animals 370
disaccharides 236
disc plough 137
disease management
in cattle 328
in crops 197-8, 201, 202, 203
in pigs 327
in sheep 326
disease resistance
farm animals 269
plants 181-2, 197
DNA 175, 176, 181
Dolly the sheep 278
dolomite 112, 345
dominant allele 178, 266, 268
donors 276-7
drainage 112, 118, 131, 134
drain formation 348-9
drenching farm animals 369
dressed weight 304
dressing percentage 304-5,
359-60
drills 135
driver, economy 42
dry farming techniques 118
dry season 16, 106, 244
drying, food 219, 330
duodenum 229, 230
dusting animals 370
dysentery 294
earthquakes 24
earthworms 94
Eastern Caribbean Institute of
Agriculture and Forestry
(ECIAF) 6, 10
Economic Partnership Agreement
(EPA) 11
economics
consumption, marketing and
production 42-4
losses from praedial larceny 18
ecosystem diversity 21
education 4, 6, 9, 10
egestion 226
eggs 301
formation in poultry 274-5
incubation 275-6
marketing 306, 359
sources of 265
structure 231-2
elephant grass 245
Index
embryo (seed) 150, 152, 157, 158
embryo transfer 270, 276-8
employment
agricultural sector 2-3
careers in agriculture 3-6
endodermis 147
engine, economy 42
ensilage 247-8
environmental effects
in agriculture 20
chemicals 198-200
degradation 23
modem farming 32
natural hazards 24
organic farming 35
on plant growth and
development 167-8
environmental sanitation 371
enzymes
in digestion 226, 230
in food spoilage 217, 219
in germination 157
epidermis 147, 148, 149
epididymis 323
epigeal germination 158
equilibrium point 55
equilibrium price 54
equipment see machinery; tools
essential resource 45
etiolation 167
European Union (EU) 11, 64-5
eutrophication 199
expenditure 84
Extension, Training and
Information Division 8
extension officers 4, 18
extension services 6, 18
extensive systems, fish farming
257
external parasites 368-70
faeces 230, 231
fair trade 3, 11
fallow land 191
family labour 45
farm animals
artificial insemination 270-1
breeds see breeds
disease resistance 269
dressing percentage 304-5,
359-60
feed conversion ratio 240-1, 305
first aid 366-7
genetic inheritance 266
good hygiene 368
grazing 193, 241-4
housing requirements see
housing
livestock records 83
management practices in
rearing 322-9, 364-71
parasite control 368-70
products and by-products from
301-4, 333-5
reproductive systems 323-4
and soil erosion 116
see also individual farm animals
farm planning 81
farm proposal 71
farm records 71, 82, 85
poultry 323
production records 82-3, 85
sheep 326
tools and machinery 138
vegetable crops 200-3
farmers 4
registration 70
tenant farmers 19, 45
farming
farm management 81-4
fish farming 257-9
mixed farming 32, 42, 189
modem farming 32
non-conventional farming
33-5
organic farming 33, 35-8
traditional farming 32
farrowing 274, 326, 365
fats (lipids) 236-7
feed conversion ratio (FCR)
240-1, 305
feeding
cattle 328
pigs 327
poultry 239, 322
rabbits 231
sheep and goats 325
see also animal feeds
feedstuffs 239
fermentation 220-2, 248
fertilisation 152, 273
fertiliser ratio 109-10
fertiliser spreader 137
fertilisers
applying 111, 112, 190, 343-5
causing eutrophication 199
for horticultural plants 313
for lawns 317-18
NPK fertilisers 111, 199, 315
organic and inorganic 108,
110-11
in organic farming 33, 38
for ornamentals 315
record form 84
simple and compound 109-10,
Ill
timing of application 131
for vegetable crops 201, 202,
203, 323
fetus 273
fibrous roots 147
field capacity 97
fingerlings 258, 259
finisher ration 289
fireblight 195
first aid for animals 366-7
fish 302
fish farming 257-9
fish feed 258
Fisheries Division 8
fixed capital 47, 69
fixed costs 48
fixed inputs 47, 49, 50
flea beetle 194
floods 24
flowers 146, 151 -2, 167
quality requirements 316
see also ornamentals; individual
flowers
focus, in production 42
fodder 239
food
imported 3
inspection 5
preservation 217, 219, 330-1
processed see food processing
see also animal feeds; digestion;
feeding
Food and Agricultural
Organisation (FAO) 11, 26
food processing 217-22
safety requirements 333
food production
careers in 4
HACCPs in 26-7
mechanisation 5
using GM 182
food safety 20, 333
terminology 26-7
food security 2, 23
foot rot 326
forages 239, 241, 243, 244-7
conservation 247-8
identifying, collecting and
mounting 355-6
foreign exchange earnings 2
Forestry Division 8
forests, and soil conservation 117
fossil fuels, burning 24, 105
fowl pox 290
frame hive 256, 257
free movement, capital, goods,
people and services 62-3
Free Trade Area of the Americas
(FAA) 64
freeze-drying 219
freeze-thaw weathering 92
freezing process 219, 330
freshwater farming 257-9
fruit crops
cultivation 312-15
establishing an orchard 360
pollination by bees 291
see also individual fruits
fruit fly 194
fruit moth 194
fuels, safety precautions 140
fungi 104, 195, 196
fungicides 197
furrows 349-50
gabions 118
gametes 152, 175
inheritance 178-9
in meiosis 177
GAPs (Good Agricultural
Practices) 26
gastric juice 229
gender issues 20-1
genes 176, 177
disease-resistant 181
transfer 278-9
see also alleles
genetic code 175
genetic diversity 21
genetic engineering 181, 182
in animal production 278-9,
335
genetic improvement, principles
of 269-70
genetic inheritance 175-8
animals 266
characteristics 178-80, 267,
268
in plants 179-81
genetically modified (GM) crops
33, 182, 279
genetically modified organism
(GMO) 278, 279
genotype 178, 179
germination 157-9
weeds 190, 191
germplasm 181
gestation 273
giblets 305
ginger lily 212, 315, 316
gizzard 226, 227
glaciers 93
Gliricidia 246
global warming 22, 105
globalisation 21
glucose 164
Glyphosate 192
GM crops 33, 182, 279
goats
breeds 264, 265, 324
rearing 324-6
reproduction 272, 273
Good Agricultural Practices
(GAPs) 26
Good Manufacturing Practices
(GMPs) 27
goods 42, 43
free movement of 62
government institutions, sources
of capital 70
grading, eggs 306, 359
grafting 156, 157, 351
grass barriers 117
grassed drains 117
grasses 146,244-5
for grazing 241
lawn and turf 317-18, 362-4
grazing 193, 245
systems 241-4
green manure 36, 110, 189
greenhouse effect 21, 22, 105
greenhouse gases 21, 22
gross income 85, 86
gross margin 86
Gross National Product (GNP) 2
grow boxes 34
grower ration 289, 322
growth in plants
environmental factors 167-8
stages of 163-4
guano 110
guaranteed prices 75
375
Index
guarantor 71
Guatemala grass 245
Guinea grass 245
gullies 115
Guyana School of Agriculture
( GSA) 10
halal meat 44
hand weeding 192
handling 44
haploid number 177
hardening 163
harrow 137
harvesters 135, 211
harvesting 209-11
high quality produce 212-13
horticultural plants 312, 313,
314, 315, 316
ornamentals 211-12, 362
vegetable crops 201, 202, 203
hay making 247
hazard analysis 27
Hazard Analysis Critical Control
Point (HACCP) 26-7
hazardous chemicals 108
health concerns, consumers 44
heat period 272, 273
heliconia 212, 315, 316
herbaceous stems 148
herbage 231, 244
herbicide-resistance 182
herbicides 192-3
herbs 145
heritability 267, 270
hermaphrodite 151
heterozygous 178, 179, 266, 268
hives 256, 292
hoeing 192
homogenisation 301
homozygous 178, 179, 266, 268
honey 291, 294-5, 302
hormones, in pest control 37
horticultural plants 312-16
horticulture 311, 360-4
host 181
housing
broilers, layers and rabbits
254-6, 356-8
cattle 328
farm animals 253-4, 364-5
good hygiene 368
rabbits 364
sheep 325
human activities, effects on soil
94, 114
humidity 107
humus 94, 97, 103
hurricanes 24, 25, 126, 131
hutches 255
hybrid vigour 268-9
hybrids 181, 211, 268
hydroponics 33, 34
hygiene 333, 368
hygrometer, wet and dry bulb
128
hypogeal germination 158
376
ice, weathering due to 92
igneous rocks 107
ileum 227, 229, 230
inbreeding 267
incentives 75-6
income 84, 85, 86
income level, consumers 32
increasing returns 49
incubation 275-6
index (thermometer) 128
infrastructure 17
infundibulum 323
ingestion 226
inheritance see genetic
inheritance
inoculation, chicks 365-6
inorganic fertilisers 108, 110-11
input 47-8, 49, 50
insect pests 194, 195
insect-pollination 152
insecticides 197, 199
see also pesticides
insurance companies 70
integrated control, weeds 193
integrated pest management
(IPM) 37, 198
intensive systems, fish farming
258-9
Inter-American Development
Bank (1DB) 12
Inter-American Institute for Cooperation on Agriculture
(IICA) 11
intercropping 36, 188
internal parasites 368-9
International Federation of
Organic Agricultural
Movements (IFOAM) 33
international institutions,
agricultural development
11-12
International Labour
Organisation (ILO) 46
International Sugar Agreement
(ISA) 65
International Sugar Organisation
(ISO) 65-6
international trade agreements
62-6
Intertropical Convergence Zone
(ITCZ) 130
inventory system 82
iodine 237
iron 109, 237
irrigation 106, 134, 190
jam-making 218
Jamaica Hope cattle 264, 266,
269
job descriptions 4
joint ownership 72
journalism 6
kindling 274
knapsack sprayer 138-9, 140
Kudzu 246
labour, production factor 45-6
labour costs 46
labourers 4
lactation 328
lamb 303, 332
land
clearing 116, 131-2, 247-8
fragmentation 19
management 108
pollution 24
preparation 131-4, 201,
347-50
production factor 45
tenure 19, 45
Land Administration Division 8
landslide 115
latosols 96
law of demand 52
law of diminishing returns 47-51
law of supply 54
lawns 317-18, 362-4
layering 154-5, 351-2
layers see poultry
laying (egg) ration 289, 322
leaching 103, 131
leaf litter 117
leaves 146, 148-9
legume crops 117, 188, 193, 246
lettuce, cultivation 202-3
Leucaena 246
levelling 134
liabilities 84, 85
limestone 112, 113, 345
liming materials 112
live weight 304
liver 227
livestock see farm animals
loam 98, 99
loans 46-7
obtaining 70-1
local institutions, agricultural
development 7-8
Lome Convention 64
long-day plants 167
long-term planning 81
lumber 253
luxury goods 43
machinery
crop production 135-7, 211
in hilly areas 17
safety precautions 139-40
see also tractors
machines, definition 135
macronutrients 102
fertiliser ratio 109-10
magnesium 102, 237
maintenance ration 238, 244
maize
germination 158, 159
harvesting 211
management
co-operative 74
farm management 81-4
land management 108
pasture 242-3, 370-1
production factor 45, 47
management practices
in livestock rearing 322-9,
364-71
rearing broilers, layers and
rabbits 287, 288-9
managers 4, 6, 47
manganese 109, 237
mange 291
mangoes 313
manual harvesting 210-11
manure 35, 108, 110, 113
biogas from 304, 335
from cattle 328
green manure 36, 110, 189
pen manure 110, 113, 346
from poultry 322-3
value-added products from
334-5
manure spreader 137
Marek's disease 290
marginal cost 48
marginal output 49, 50
marine farming 257, 259
market demand schedule 51
market gardens 35
market supply schedule 53
marketing 44
eggs 359
eggs and meat 306-7
value-added products 333-4
vegetable crops 201, 202, 203
marketing co-operatives 73
materials, livestock housing
253-4
mating 270
maturity, signs of 209, 210-11
maximum prices 56
meat 265, 302-3
marketing 306-7
quality requirements 332
medicinal products, from bees
295-6
meiosis 175, 177, 178
melongene, harvesting 211
merchandising 44
mesophyll 149
metabolic rate 167
metamorphic rocks 108
micelle 103
micronutrients 102, 102
and crop production 108-9
microorganisms
in digestion 226, 228, 231
in fermentation 220, 221
and food processing 217, 218, 219
in soil 104
see also bacteria
micropyle 150
middlemen 44
milk 265, 301, 324
pasteurisation 330
production 328-9
milking shed 328
minerals
active transport 166
dietary 237
in soil 96-7, 98, 102, 103
Index
miniature golden apple 314-15
minimum fixed prices 56
minimum wage policy 46
Ministry of Agriculture
divisions 8
extension services 6
sources of capital 70
mitochondria 175
mitosis 175, 176
mixed cropping 187-8
mixed farming 32, 42, 189
molybdenum 109, 237
money-lenders 70
monocots 145-6,148. 149, 150, 159
monoculture 32, 187
monohybrid inheritance 179-80
monosaccharides 236
mouldboard plough 137
moulding 99, 189
mouth 227, 229, 230
mowing 318, 363-4
mulberry 247
mulching 116, 189, 191
multicellular organisms 175
multiple cropping 187-8
mycoplasmas 195, 196
national economy, agricultural
importance to 2
National Marketing and
Development Corporation
(NAMDEVCO) 62
national plans, agricultural
development 3
natural brooding 286
natural disasters 20
natural hazards 24, 25
natural incubation 275
nectar 152, 292, 293
neem 247
nematodes 195, 196
Net Energy Values (NEV) 239
net income 85, 86
net profit 86
net worth 84-5
Newcastle disease 290
nitrates 105, 106, 199, 331
nitrifying bacteria 106
nitrites 105, 106, 331
nitrogen 102, 102, 103
in fertilisers 109, 111
nitrogen cycle 104, 105-6
nitrogen-fixing bacteria 106
nitrogen oxides 105
non-profit business 72
non-selective herbicides 192
NPK fertilisers 111, 199, 315
NPK ratio 109-10, 111
nucleus 175
nursery 162-3
nutrient film technique (NFT) 33-4
nutrients 101-3
in animal nutrition 236-8
in forages 244
in legumes 246
see also macronutrients;
micronutrients
nutrition 226
nutritional scours 326
NVQ level qualifications 4
0 horizon 95
ochro, harvesting 210
oesophagus 226, 227, 229, 230
oestrus cycle 272, 277
offal 303
oil spillage 24
omasum 228, 229, 230
open membership 72
optimum price 51
orchids 212, 315, 316
organelles 175
organic farming 33, 35-8
organic fertilisers 108, 110
organic matter 94, 96, 97, 112
in composting 113
leaf litter 117
mulches 116
Organisation of American States
(OAS) 11
organisms
in soil 94, 100, 101
unicellular and multicellular
175
see also microorganisms
organs of perennation 152, 153
ornamentals 311, 315-16
harvesting 211-12, 362
see also flowers
osmosis 165
output 48, 49, 50
marginal 47, 49, 50
ovaries 323
over-cultivation 45
overseers 4
oviduct 274, 275, 323
ovulation 272
ovules 151, 152
ovum 274, 278
oxidation 93, 217
oxygen
for germination 157
in photosynthesis and
respiration 164
weathering due to 93
packaging 209, 218, 305, 306-7
palisade mesophyll 149
pancreatic juice 230
pangola grass 244-5
para grass 245
Paraquat 192
parasites, control measures
368-70
parent cell 176, 177
parent material 107
partial budget 86-7
parturition 274, 325
pasteurisation 218, 301, 330
pasture management 242-3,
370-1
pathogens 195, 196
patron-members 72
pawpaw, harvesting 211
pen manure 110, 113, 346
penis 323
pens 253, 254
cleaning and disinfecting 358
people, free movement of 63
percentage germination 157
perennials 145
performance testing 269-70
peri-urban fanning 35
pericycle 147
peristalsis 228, 229
personal savings 70
pest control
horticultural plants 312, 313,
314
management 197-8, 201, 202,
203
ornamentals 316
during plant growth 168
in sheep 326
using GM 182
pesticides 197
environmental problems 199
labelling 200
in organic farming 33, 37, 38
sprayer 138-9, 140
timing of application 131
pests
alien 203
of bees 293-4
and crop damage 193-4
of poultry and rabbits 290-1
in weed control 193
pets 265
pH, soil 103-4
phased cropping 188
phenotype 178, 179
phloem 147, 148, 149, 166
phosphates 199
phosphorus 102, 102, 237
in fertilisers 109, 111
photoperiodism 166-7
photosynthesis 105, 149, 164,
167
phototropism 166, 167
physical weathering 92-3
phyto-sanitary certification 20
pigs
breeds 264, 265
digestion in 229-30
digestive system 228, 229
farrowing 274, 326, 365
feed conversion ratio 240
meat cuts 303
rearing 326-7
reproduction 272, 273
Planning Division 8
plant breeding 178-81
plant cells 175
plant quarantine 203-4
planting
fruit vegetable crops 201, 202,
203
horticultural plants 312, 313,
314
plants
asexual reproduction 152-6
classification 145
development see growth in
plants
disease-resistant 181-2, 197
growth see growth in plants
inheritance in 179-81
processes 164-7
sexual reproduction 151-2
structure 145-50
see also crops; forages;
horticultural plants; seeds
ploughing 192
ploughs 137
plugs 317
plumule 150, 158, 159
pollen 151, 152, 291, 293, 295-6
pollination 151-2, 291
polysaccharides 236
ponds 117-18, 258
pork 303, 332
porosity, soil 100
post-harvest handling 209
high quality produce 212-13
horticultural plants 312, 313,
314, 315
ornamentals 211-12
vegetable crops 201, 202, 203
potassium 102, 102, 237
in fertilisers 109, 111
potting soil 159, 160, 161
poultry
breeds 264, 265
brooding in 286-8, 357-8
debeaking 288, 289, 366
digestive system 226-7
egg formation and incubation
274-6
housing requirements 254-5,
356-8
inoculation of chicks 365-6
meat cuts 303, 332
pests and diseases 290-I
rations for 239, 322
rearing 288-9, 289, 322-3
returns and costs 48, 50-1
slaughter 305
space requirements 356-7
praedial larceny 18-19
predators 197-8, 253
pregnancy detection kits 273
prey 197-8
price 51, 52, 53, 54, 55
price mechanisms 55-6
price support 75, 76
pricing 54-5
primary production 43
primary products 43
primary tillage 132, 347-8
processed food 222
processing 44
agro-processing 5
by-products for animal feed
238
co-operatives 73
crops 217
meat 306
see also food processing
377
Index
produce co-operatives 73
producers (plants) 104
production 42-3
factors 44-7
records 82-3, 85
see also agricultural production;
animal production;
crop production; food
production
production ration 238
products
from animals 301-4
choice of 81
primary and secondary 43
substitutes 44
professional services 43
profit 49
profit and loss account 84
progeny testing 270
Project Implementation Unit 8
propagation 350-3
artificial 154, 156
horticultural plants 312, 313,
314
omamentals 315
propagator 154
propolis 293, 295
proteins 236
protozoa 104, 196
proventriculus 226, 227
pruning 190, 313
pseudo-ruminants 231
pullorum 290
purchasing co-operatives 73
qualifications 4, 6, 9, 10
quality control 5
quality grades 332
quarantine, plant 203-4
quasi-stationary front 130
rabbits
breeds 264, 265
brooding and rearing 288
digestion in 231
gestation 273
housing requirements 255,
358, 364
kindling 274
pests and diseases 291
production records 83
radicle 150, 158, 159
rain gauge 127
rainfall 106, 127, 129
effect on crops 126
effect on farming 131
and plant growth 167
rainy season 106, 115, 126, 131,
244
ration 238-9, 244, 289, 322
rats 193
recessive allele 178, 266, 268
records see farm records
rectum 227, 229, 230
recycling, waste materials 32
refrigeration 218
378
Regional Administration
Divisions 8
regional institutions, agricultural
development 9-10
regional plans, agricultural
development 3
religious beliefs, consumers 44
rendzina 96
rennin 182
reproductive stage, growth 164
reproductive systems, farm
animals 323-4
Research Division 8
research workers 4
residual pesticides 197
respiration 105, 164-5
reticulum 228, 229, 230
returns 49-51
Rhizobium 105
rhizomes 148, 153, 157
ribosomes 175
ricin 23
ridging 116, 349-50
rills 115
ring placement 344
risk 71, 75
rocks, types of 107-8
root crops, cultivation 201-2
root cuttings 154
root system 146
roots 147, 154
osmosis 165
roses 315
rotational grazing 241, 243
rotovator 137
royal jelly 292, 296
rumen 228, 229, 230
ruminants 228, 229, 230
runners 153
rural infrastructure 17
rural-to-urban drift 17
safety equipment 139, 140
safety precautions
during food processing 333
tools and machinery 139-40
using herbicides 193
sales and marketing careers 4
saliva 229, 230
saltation 115
salting 331
sand 97, 98, 99, 103
sanitary certification 20
sauerkraut 220
scarification 158
scion 155, 156, 157
scrotum 323
secondary production 43
secondary products 43
secondary tillage 133, 347-8
security 71
sedimentary rocks 107
seed banks 181
seed (flowering) plants 145, 151
seedbeds 160-1, 353-4
seedboxes 159, 353
seeders 135
seedlings 159-61
thinning out 162, 354-5
transplanting 163
seeds 150, 152, 156
buying good quality 191
germination 157-9
for lawns 317
sowing 159-61, 162
from weeds 190, 191
selective breeding 175, 180
selective herbicides 192
self-pollination 151
semen 270-1
seminal vesicles 323
service co-operatives 73
service industry jobs 5
service investments 72
services 42, 43
free movement of 63
sexual reproduction 178
animals 272, 273
crops/plants 151-2, 156
sharecropping 45
sheep
breeds 264, 265, 324
clones 277-8
meat cuts 303
pest and disease management
326
rearing 324-6
reproduction 272, 273
shelf life 213
shoot system 146
short-day plants 167
short-term planning 81
shrubs 145
side placement 343
signs of heat 272-3
silage 239, 245, 247-8
silos 247
silt 97, 98, 99, 103
silting up 115
silviculture 108
simple fertilisers 109, I 1 1
simple leaves 148
slaughter 305, 306
slurry 110
smallholdings 45
smallpox 22
smoking, food 331
snuffles 291
soil
aeration 98, 101
components and structure
96-8
disinfection and sterilisation
159, 197
formation 92-4
GAPs relating to 26
microorganisms in 104
organisms in 94, 101
pH 103-4
potting soil 159, 160, 161
temperature 101, 106
and water conservation 117-18
soil amendments 108, 110-12
techniques in applying 345-6
soil creep 115
soil erosion 25, 114, 115-16, 117
soil fertility 106-8
loss of 45
maintaining 110-12
in organic farming 36
and plant growth 168
soil horizons 95
soil management 116-17
organic farming 36
soil nutrients 101-3
soil profile 95-6
sore hocks 291
Sou-Sou groups 70
sowing seeds 159-61, 162
soya sauce 220
space requirements, poultry
356-7
species diversity 21, 35
Speedling trays 160, 161
sperm 270, 273
spongy mesophyll 149
spray pastures 369
spraying farm animals 369-70
sprigs 317
staking 190
stamens 151
starch 164
stem cuttings 154
stems 146, 148
sterilisation 301
soil 159, 197
Stevenson screen 128
stigma 151
stock (consumables) 69
stock (plant) 155, 156
stocking rate 241, 242
stolons 153
stomach 228, 229
stomata 148, 149, 165
storage tanks 117
strip cropping 117, 188, 189
strip grazing 242, 243-4
Stylosanthes 246
sublimation 219
subsidies 56, 75-6
subsoil 95
suckers 153
sugar cane 187, 193
Sugar Cane Feeds Centre 258
sulphate of ammonia 113
sulphur 102, 237
sulphur dioxide 24
sun, weathering due to 93
sunlight, and plant growth 167-8
super (bee housing) 257
supply 53-4, 55
supporting 44
surrogates 276-7
sustainable land use 19
swarming 292
systemic herbicides 192
systemic pesticides 197
table eggs 301, 359
tanner grass 245
tap roots 147
Index
tariffs 3, 11, 63
taxation 56, 75
team management 72
technical services 43
temperature
effects on farming 131
for germination 157
measuring 128
and plant growth 167
soil 101, 107
tenant farmers 19, 45
termite 194
terracing 117
test cross 179
testa 150, 157
testes 323
thermometers 128
thinning out 162, 354-5
tillage 100, 112, 132-3
minimum 116
primary and secondary 132,
133, 347-8
tissue culture 156, 157
tomatoes 146, 201, 210
tongue layering 154-5
tools
care and maintenance 138, 350
safety precautions 139-40
top bar hive 256
topography 16-17, 45
and soil fertility 107
total cost 48
Total Digestive Nutrients (TDN)
239
total output 49, 50
toxicity, pesticides 199
tractors 136-7
attachments 137, 211
safety precautions 140
in tillage 132, 133
trade barriers 3, 62, 63, 64
trade liberalisation 3, 11
traditional farming 32
trailer 137
training centre