Organic Farming: Horticulture
An Ability Enhancement Course (21EEAE46A)
Sangamesh G Sakri
Copyright © 2023 Sangamesh G Sakri
P UBLISHED BY AUTHOR
First printing, January 2023
Contents
Module I
I
1
Concepts and Principles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.1
Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.1.1
Organic Farming - Concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.2
Concepts of Organic Farming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.3
Principles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
1.3.1
1.3.2
1.3.3
1.3.4
Principle of Health . . . . .
The Principles of Ecology
Principle of Fairness . . . .
Principle of Care . . . . . .
1.4
Soil Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
1.5
Organic Farming and Climate Change . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
1.5.1
1.5.2
1.5.3
Organic Farming Reduces Greenhouse Gases . . . . . . . . . . . . . . . . . . . . . . . . . 20
Organic Farming Improves Soil Carbon Sequestration . . . . . . . . . . . . . . . . . . . 21
Organic Farming Increases Resilience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
1.6
Importance of Horticultural Crops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
1.6.1
Features and importance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
II
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14
14
15
15
Module II
2
Horticulture Crops and Human Nutrition . . . . . . . . . . . . . . . . . . . . . . . . 25
2.1
Functions of fruits and vegetables in human body . . . . . . . . . . . . . . . . . . 25
2.2
Selection of seeds, seedlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
2.3
Climatic condition of a crop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
2.4
Essential Plant Nutrients and their Deficiency Symptoms . . . . . . . . . . . . . 28
2.4.1
2.4.2
Role of essential elements in plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Plant Nutrients Deficiency Symptoms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
2.5
Toxicities in Horticultural Crops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
2.6
Toxicity Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
2.6.1
Specific Ions and Their Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
2.7
Toxicity Effects Due To Sprinkler Irrigation . . . . . . . . . . . . . . . . . . . . . . . . . . 33
2.7.1
Prevention of toxicity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Module III
III
3
Organic Manures and Compost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
3.1
Organic Manures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
3.1.1
3.1.2
3.1.3
3.1.4
3.1.5
Bulky organic manures . . . . . . . .
Farmyard manure . . . . . . . . . . .
Poultry Manure . . . . . . . . . . . . . .
Concentrated organic manures
Oil cakes . . . . . . . . . . . . . . . . . .
3.2
Inorganic Manures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
3.3
Compost Production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
3.3.1
3.3.2
3.3.3
Benefits of composting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Nutrient composition of compost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Composting process – 3 phases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
3.4
Vermi-compost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
3.4.1
Process of Vermicomposting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
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37
38
39
39
39
Module IV
IV
4
Pest & Disease Management and Harvesting . . . . . . . . . . . . . . . . . . . 49
4.1
Pest & Disease Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
4.2
Organic Methods of Pest and Disease Management . . . . . . . . . . . . . . . . 52
4.2.1
Vegetable pests: Type-2 (Sucking borers) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
4.3
Weed Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
4.3.1
4.3.2
4.3.3
Critical period of weed control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Cultural Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Water management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
4.4
Mechanical Weed Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
4.5
Thermal Weed Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
4.5.1
4.5.2
4.5.3
4.5.4
Flamers . . . . . . . .
Soil solarization . .
Infrared weeders
Freezing . . . . . . .
4.6
Biological Weed Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
4.6.1
4.6.2
4.6.3
4.6.4
Allelopathy . . . . . . . . . . . . . . . . . . . . . . . . .
Beneficial organisms . . . . . . . . . . . . . . . . .
Use of biocontrol agents for weed control
Use of fish for weed control . . . . . . . . . . . .
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59
60
60
60
60
61
61
61
5
4.7
Harvesting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
4.7.1
4.7.2
Timing of harvest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Method of harvest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
4.8
POST HARVEST MANAGEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
4.8.1
4.8.2
4.8.3
4.8.4
Stripping . . . . . . . . . . . .
Drying . . . . . . . . . . . . .
Packaging and storage
Shelling . . . . . . . . . . . . .
4.9
Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
4.9.1
Packaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
4.10
Handling and Storage of Horticultural Crops . . . . . . . . . . . . . . . . . . . . . . . 67
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64
64
64
65
4.10.1 Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
V
Module V
5
Case Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
5.1
Case studies of successful organic farming . . . . . . . . . . . . . . . . . . . . . . . . 73
5.2
Visit to a nearby organic farm/horticulture institute and report writing . 73
Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Articles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Books . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
I
Module I
1
Concepts and Principles . . . . . . . . . . . . . . 9
1.1
1.2
1.3
1.4
1.5
1.6
Concepts . . . . . . . . . . . . . . . . . . . . . . . .
Concepts of Organic Farming . . . . . . . .
Principles . . . . . . . . . . . . . . . . . . . . . . . .
Soil Preparation . . . . . . . . . . . . . . . . . . .
Organic Farming and Climate Change
Importance of Horticultural Crops . . . .
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12
12
13
16
20
. 21
1. Concepts and Principles
What is Organic Farming?
Organic farming is an ecological production management system that promotes and enhances
biodiversity, biological cycles and soil biological activity. Biodiversity action includes many
crops at a time, so that it minimizes the insect, pest and disease pressure.
Biological cycle means growing of different crops in rotation. So, by doing, the soil fertility
increases, at the same time reduces the pressure of insect pest and disease. And soil biological
activity means soil is a living body, which has many microbial populations. So, this microbial
population help in nutrient release pattern in the soil and nutrient availability for the crop plants.
Organic farming, is a system which avoids or largely excludes the use of synthetic inputs; such
as fertilizers, pesticides, growth hormones and the feed additives. And to the maximum extent
feasible rely on crop rotation, crop residue, incorporates, animal manures, off-farm organic waste,
mineral rock phosphates rock minerals and biological system of nutrient mobilizations and plant
protections. Biological nutrient fixations or green manuring help in organic farming.
Organic farming, also known as ecological farming or biological farming, is an agricultural
system that uses organic fertilisers such as compost manure, green manure, and bone meal and
emphasises techniques such as crop rotation and companion planting. Organic farming is an
agricultural practice that makes use of biological pesticides and fertilizers derived from plant or
animal waste. The goal of organic farming is to create foods that are of the highest quality, have
a high nutritional value, and are free of chemicals. It strives to develop a sustainable system that
conserves energy, soil, and water; while at the same time providing general care for the environment.
In fact, the use of chemical pesticides and synthetic fertilizers was the cause of the environmental
harm that organic farming was intended to address. Or to put it another way, organic farming is a
new type of agriculture or farming that improves, maintains, and repairs the ecological balance.
Organic standards are intended to allow the use of naturally occurring substances while prohibiting
or strictly limiting the use of synthetic substances. For example, naturally occurring pesticides
such as pyrethrin are permitted, whereas synthetic fertilisers and pesticides are generally prohibited.
Copper sulphate, elemental sulphur, and Ivermectin are examples of permitted synthetic substances.
Genetically modified organisms, nanomaterials, human sewage sludge, plant growth regulators,
hormones, and antibiotic use in livestock husbandry are all prohibited. Organic farming advocates
10
Chapter 1. Concepts and Principles
Source: https://in.pinterest.com/pin/644437027935467943/
Figure 1.1: Organic Farming in a nutshell
benefits such as sustainability, openness, self-sufficiency, autonomy and independence, health, food
security, and food safety.
In general, organic farming aims to increase long term soil fertility. Soil fertility decides the
growth and development of the crops. So, maintenance of soil fertility on long term basis is essential
to have a better production through increased productions in a sustainable environment.
The organic farming also aims to control pests and diseases without harming environments. As
the yield gets effected by the use of chemical pesticides; in turn that affects human health. The
organic farming can be helpful in minimizing the pest residue in crops and without minimizing or
without affecting the crop yield.
Organic farming ensures that water stays clean and safe, through organic farming as the use of
chemical pesticides or fertilizer is minimized or eradicated, it can ensure a good quality water and
clean water for drinking.
Lastly, it produces nutritious food, feed for animals and a high quality crops to sell at good price.
11
Source: https://www.researchgate.net/figure/Organic-cycle-of-an-organic-farmingsystem_fig1_226271466
Figure 1.2: Organic Cycle of an organic farming
It is because of the balanced nutritions, supplying both macro and micro nutrients. At the same
time the stress physiology increases the quality of the crops through the increase in a concentration
of polyphenols in the plant. And finally, this aims at use of existing resources. So, the farmer needs
less money to buy farm, to buy the farm imports. If the resource available in the farm is recycled, it
will minimize the external use of inputs.
Objectives of Organic Farming
Objective 1: Food is produced with higher nutritional quality; this is the main objective of the
organic farming.
Objective 2: The activities are done with natural systems and in harmony with nature.
Objective 3: To maintain and increase soil fertility on long term basis. As soil provides the
physical support for the plants and also helps in the nutrient release that will be available for
the crops for proper growth and development.
Objective 4: Use of renewable resources as far as possible. Natural resources are used for the
nutrients management in organic farming.
Objective 5: Avoidance of all sorts of pollution namely the air pollution, soil pollution and the
water pollution through organic farming.
Objective 6: For wider social and ecological impact of farming system . This is socially acceptable
and it has a ecological harmony with the farming community.
Objective 7: Satisfaction to agricultural producers. Farmer friendly.
Chapter 1. Concepts and Principles
12
1.1
1.1.1
Concepts
Organic Farming - Concept
Organic farming has been a way of life and a tradition in our Indian farming system for centuries; it
is not a new concept. Organic farming has its own system for controlling pests and diseases in crop
and livestock production, which avoids the use of various synthetic chemicals or gene manipulation.
There are various types of organic farming that are practised in the country’s diverse climate, with
forest produce falling under this category by default. Organic farming, among other types of
farming systems, is gaining popularity due to its positive impact on the environment. Furthermore,
organic farming is labour intensive, which increases rural employment and long-term improvements
in resource quality. Organic farming is based on an intimate understanding of nature’s laws and
rules. In today’s terminology, it is a farming system method that primarily aims at cultivating the
land and raising crops in such a way that the soil remains alive and healthy through the use of
organic wastes and other biological materials, as well as beneficial microbes (biofertilizers). They
release nutrients to increase crop yield and sustainability. "Organic agriculture is a production
system that promotes the health of soils, ecosystems, and people." Organic agriculture combines
tradition, innovation, and science to benefit the shared environment and promote fair relationships
and a good quality of life for all involved.
In a broad term, organic farming is an agricultural system of food production that involves best
environmental practices. Furthermore, it also aims preservation of natural resources, and adoption
of methods that enhance biodiversity, improve the quality of land and water, and boost ecological
balance.
Organic farming completely restricts the use of chemical fertilizers and synthetic pesticides.
Furthermore, it also prohibits the use of GMOs (Genetically Modified Organism). Instead, it
encourages the use of natural fertilizers, organic manure, and composts. Moreover, it also focuses
on crop rotation and replenishment of natural resources.
1.2
Concepts of Organic Farming
•
•
•
•
•
•
•
Work as closely as possible in closed cycles and use local resources.
Preserve the natural fertility of the soil.
Avoid all forms of pollution that arises from farming practices.
Promote the tillage practices that show most concern for the environment and nature.
Produce foods of optimal nutritional values.
Reduce the use of all forms of non-renewable resources in agriculture including fossil fuels.
Work to ensure that the waste products from towns and food industries achieve a quality that
allows their re-use as fertilizers in agriculture.
• Provide all animals with living conditions that satisfies their natural behaviour patterns and
needs.
• Do everything possible to ensure that all living organisms that the farmer works with are
allies (be they microorganisms, plants or animals.)
If in the organic farming the use of off farm inputs are to be avoided, then it is called as Low External
Input Technology (LEIT). This technology concerns with the collection of crop management inputs
and technique for soil conservation, soil fertility enhancement, crop establishment, and pest control.
The delineation of the technology may serve either a restrictive or integrative purpose. So, in LEIT,
there is a use of the inputs of the farms only, and they are recycled back in the organic farming. So,
for the practices, the following low external input technologies can be used: soil conservation, soil
fertility enhancement, crop establishment, pest control.
The social criteria for the low external input sustainable agriculture is widespread and has
equitable adoption potential especially among the small farmers. This will have reduced dependency
on external institution, enhanced food security at the family and national level, respecting and
1.3 Principles
13
building on indigenous knowledge beliefs and value systems, then contribution to employment
generation. Usually in organic farming or the ecological farming or the traditional farming the
farmers may have their traditional knowledge before the use of the insecticides or the pesticides.
The farmers use to take care of the crops against the insect, pest and disease; they used to grow
the crops as a normal practice form using only farm and manures. So, there is some indigenous
knowledge in the agricultural field and also some scientific findings. So, there is a linkage of
indigenous knowledge to scientific finding that also should be looked into.
Conventional Farming Vs. Organic Farming – Overview
Table 1.1: Comparison of Modern and Organic Farming
Framing Technique
Fertilizers Used
Use of GMO
Sustainability
Disease Resistance
Health Concerns
Environmental Concerns
1.3
Modern Farming
Involve methods based on synthetic inputs.
Chemical fertilizers like DAP, Urea, and DDT
Heavy use of GMOs for better yield and disease resistance.
No, sustainability. Yield focused.
More adapted to disease resistance, thanks to pesticides.
Heavy use of chemicals poses health risks.
Intensive farming detrimental to land, soil, and water.
Organic Farming
Depends on organic ways, rejects synthetic.
Only fertilizers obtained through organic ways.
No to GMO. Use of bio-diversity and good bacteria.
Sustainability and Care for ecology & environment.
Vulnerable to disease and pest attacks.
No health risk as absence of harmful chemicals.
Improve the overall ecology.
Principles
IFOAM Principles: International Federation of Organic Agricultural Movement was started in
February, 1972 in Germany. So, their principles of organic agricultures are health, to sustain and
enhance the health of soil, plant, animal, humans and planet as one and indivisible.
Source: https://www.nibio.no/en/subjects/food/organic-agriculture
Figure 1.3: Principles of Organic Farming (IFOAM)
The Principles of Health, Ecology, Fairness, and Care are the roots from which organic agriculture grows and develops. They express the contribution that organic agriculture can make to the
world, and a vision to improve all agriculture in a global context.
Chapter 1. Concepts and Principles
14
Source: https://www.researchgate.net/figure/The-main-principles-and-effects-of-organicfarming_fig1_338066368
Figure 1.4: Principles and Effects of Organic Farming (IFOAM)
1.3.1
Principle of Health
Organic agriculture should sustain and enhance the health of soil, plant, animal, human and planet
as one and indivisible.
Health is the wholeness and integrity of living systems. It is not simply the absence of illness, but
the maintenance of physical, mental, social and ecological well-being. Immunity, resilience, and
regeneration are key characteristics of health.
The role of organic agriculture, whether in farming, processing, distribution, or consumption,
is to sustain and enhance the health of ecosystems and organisms from the smallest in the soil to
human beings.
In particular, organic agriculture is intended to produce high quality, nutritious food that
contributes to preventive health care and well-being. In view of this, it should avoid the use of
fertilizers, pesticides, animal drugs and food additives that may have adverse health effects.
1.3.2
The Principles of Ecology
Organic agriculture should be based on living ecological systems and cycles, work with them,
emulate them and help sustain them.
This principle roots organic agriculture within living ecological systems. It states that production is
to be based on ecological processes, and recycling.
Nourishment and well-being are achieved through the ecology of the specific production
environment. For example, in the case of crops this is the living soil; for animals it is the farm
ecosystem; for fish and marine organisms, the aquatic environment.
Organic farming, pastoral and wild harvest systems should fit the cycles and ecological balances
in nature. These cycles are universal but their operation is site-specific. Organic management
must be adapted to local conditions, ecology, culture and scale. Inputs should be reduced by reuse,
recycling and efficient management of materials and energy in order to maintain and improve
environmental quality and conserve resources.
Organic agriculture should attain ecological balance through the design of farming systems,
1.3 Principles
15
establishment of habitats and maintenance of genetic and agricultural diversity. Those who produce,
process, trade, or consume organic products should protect and benefit the common environment
including landscapes, climate, habitats, biodiversity, air and water.
1.3.3
Principle of Fairness
Organic agriculture should build on relationships that ensure fairness with regard to the common
environment and life opportunities. The role of organic agriculture, whether in farming, processing,
distribution, or consumption, is to sustain and enhance the health of ecosystems and organisms
from the smallest in the soil to human beings. Fairness is characterized by equity, respect, justice
and stewardship of the shared world, both among people and in their relations to other living beings.
This principle emphasizes that those involved in organic agriculture should conduct human
relationships in a manner that ensures fairness at all levels and to all parties - farmers, workers,
processors, distributors, traders and consumers. Organic agriculture should provide everyone
involved with a good quality of life, and contribute to food sovereignty and reduction of poverty. It
aims to produce a sufficient supply of good quality food and other products.
This principle insists that animals should be provided with the conditions and opportunities of
life that accord with their physiology, natural behavior and well-being.
Natural and environmental resources that are used for production and consumption should
be managed in a way that is socially and ecologically just and should be held in trust for future
generations. Fairness requires systems of production, distribution and trade that are open and
equitable and account for real environmental and social costs.
1.3.4
Principle of Care
Organic agriculture should be managed in a precautionary and responsible manner to protect the
health and well-being of current and future generations and the environment.
Organic agriculture is a living and dynamic system that responds to internal and external demands
and conditions. Practitioners of organic agriculture can enhance efficiency and increase productivity,
but this should not be at the risk of jeopardizing health and well-being. Consequently, new technologies need to be assessed and existing methods reviewed. Given the incomplete understanding
of ecosystems and agriculture, care must be taken.
This principle states that precaution and responsibility are the key concerns in management,
development and technology choices in organic agriculture. Science is necessary to ensure that
organic agriculture is healthy, safe and ecologically sound. However, scientific knowledge alone is
not sufficient. Practical experience, accumulated wisdom and traditional and indigenous knowledge
offer valid solutions, tested by time. Organic agriculture should prevent significant risks by
adopting appropriate technologies and rejecting unpredictable ones, such as genetic engineering.
Decisions should reflect the values and needs of all who might be affected, through transparent and
participatory processes. The principles of organic farming as seen by others who are practicing it.
there are three basic principles of organic farming say cyclical principle, precautionary principle
and nearness principle.
Cyclical principle Collaboration with the Nature be promoted through establishment and build up
of a cyclical principle that ensures versatility, diversity and harmony, and the re-cycling and
use of renewable resources.
This is a close recycling or the crop cycle. As per this principle crops are to be grown one
after the other from different groups and same crops should not be repeated after season. By
changing the crops one crop after another in different seasons the pest and disease population
can be minimized in the field at the same time the soil fertility can be maintained so also
there will be improvement in the soil fertility for long term. This principle talks about the
biodiversity.
Precautionary principle Known and well functioning technologies are better that risky technolo-
16
Chapter 1. Concepts and Principles
gies. It is better to prevent damage than to depend our ability to cure the damage.
This talks about the prevention which is far better than cure. So, use of anything, any materials that is not allowed in organic farming is strictly avoided. It means better to avoid the use
of any chemical insecticides and pesticides that is the precautionary principle.
Nearness principle Transparency and co-operation in food production can be improved by nearness. For example using experience based knowledge and local interests concerning the
development of cultural and social values.
This principle means transparency and trust building which is also very important in organic
farming. It talks about the trust building among the producers and the consumers. If the
product is said to be organic then it should be really organic, there should be honesty in
the approach of the farmers in producing organic food products. This will clear all the
ambiguity and transparency will be developed to improve health, knowledge, develop market
and culture.
So, nearness principle the transparency close association producers and the consumer this
should be a close association there should be the trust building among the producers and the
consumers. So, there should be very transparent if it is a organic that is a organic; if it is not
organic that is a non organic. So, this type of the trust building among the producers and the
consumers should be develop and there should be in very close low for the successful of this
organic farming.
Organic Agriculture is a living and dynamic system that responds to internal and external demands
and conditions.
Practitioners of organic agriculture can enhance efficiency and increase productivity, but this
should not be at the risk of jeopardizing health and well-being. Consequently, new technologies
need to be assessed and existing methods reviewed. Given the incomplete understanding of
ecosystems and agriculture, care must be taken.
This principle states that precaution and responsibility are the key concerns in management,
development and technology choices in organic agriculture.
Science is necessary to ensure that organic agriculture is healthy, safe and ecologically sound.
However, scientific knowledge alone is not sufficient. Practical experience, accumulated wisdom
and traditional and indigenous knowledge offer valid solutions, tested by time.
Organic agriculture should prevent significant risks by adopting appropriate technologies and
rejecting unpredictable ones, such as genetic engineering. Decisions should reflect the values and
needs of all who might be affected, through transparent and participatory processes. In particular,
organic agriculture is intended to produce high quality, nutritious food that contributes to preventive
health care and well-being. In view of this, it should avoid the use of fertilizers, pesticides, animal
drugs and food additives that may have adverse health effects.
Overall the principles of organic farming broadly focuses on the following:
• Conversion of land from conventional management to organic management.
• Management of the entire surrounding system to ensure biodiversity and sustainability of the
system.
• Crop production with the use of alternate sources of nutrients such as crop rotation, residue
management, organic manures and biological inputs.
• Better plant protection practices by physical, cultural and by biological control system.
• Maintenance of live stock with organic concept and make them an integral part of the entire
system.
1.4
Soil Preparation
Organic farming requires healthy soils to provide your plants with all the adequate nutrients they
need to grow healthy, be free of disease, and produce a bountiful harvest. Aside from just nutrients,
your soil must also contain the thriving biology of microorganisms and insects that play important
1.4 Soil Preparation
17
roles in your soil’s nutrient cycle and plant’s defense system. Before you do anything to your soil
it is best to assess what exactly you’re working with. In most cases, you can do the assessment
yourself in the field through careful observation or by using one of the over-the-counter test kits.
Alternatively, you can get a professionally conducted soil test.
Laboratory Testing Large plots of land may require multiple tests in diverse locations.
• If the plan is to go into market production it might be best to conduct a proper laboratory
test. This will give the information about the nutrients lacking and any other agro
chemicals that may be present, which are against the organic farming.
• Information Obtained From Laboratory Testing:
– Macronutrients: nitrogen (N), phosphorus (P), and potassium (K)
– Secondary nutrients like sulfur, calcium, and magnesium.
– Micronutrients like manganese, copper, zinc, boron, molybdenum, and Iron
– Presence of Agrochemicals pH Organic Matter Percentage
Field Assessment In your field assessment, you will want to analyze for compaction, soil texture,
and any indicators provided by vegetation. Soil texture refers to the quantities of sand, silt,
or clay in your soil which will affect your management decisions.
Vegetation indicators like wetland species or xeric species (adapted to dry conditions) will tell you
a lot of what’s going on in your soil. Dark soils rich in organic matter are typically a sign that
you’ve got good soil! Steps To Preparing Your Soil In most cases, you will want to follow these
steps in this order to ensure the best results for your soil.
1. Dealing With Weeds And Rocks
Weeds can become the most labor-intensive part of managing your farmland organically, so
taking the right steps to ensure they don’t proliferate is important. Ideally, remove weeds
before they go to seed, most should be removed with roots.
Weeds can be composted or fed to farm animals. You may choose to leave some weeds like
clovers and other small ground covers that have minimal impact on your crops.
Small rocks or pebbles in the soil can also be an issue, particularly for planting seeds or
container gardening. You can remove them using various methods.
2. Compaction Compaction in your soil can be extremely detrimental to your plant’s health.
It not only affects the water absorption and retention but also greatly reduces air space
within the soil. To treat compactions you will have to loosen the soil with a shovel or other
machinery.
3. Double Dig Method The Double Dig Method is a simple way to loosen the soil with the
use of a shovel. Remove the top layer of soil from your row or bed one shovel head deep.
Place soil to the side. Loosen soil that lays beneath your excavated area with a shovel,
pick, or fork. Refill with soil that was already excavated. Alternatively, if you’re planning
neighboring rows you can directly place the topsoil of the next row into your originally
excavated space. Avoid stepping on or compacting your newly loosened soil. With proper
management, double-digging will only have to be done once.
4. Consider Climate When preparing your beds you should also consider your climate. Arid
climates should have rows/beds that are at ground level while climates with heavy rain should
have raised planting areas to promote drainage.
5. Amending Soils Amendments are important to ensure your plants have all the nutrients they
need to grow healthy and productive. They should be mixed directly into the top-soil once it
has been properly loosened.
Compost Getting yourself high-quality compost is important to establishing healthy soil. Find
compost that is dark, homogenous, and composed of fully decomposed materials.
Avoid anything with large chunks of undecomposed materials or compost with unpleasant
odors. Adding 2-4” of compost is a good start but use as much as hands full.
Biochar What is biochar? Biochar is one of the most powerful organic soil amendments available
18
Chapter 1. Concepts and Principles
and serves countless benefits to soil. It can be found in most garden centers or the farmer
should learn to make it. Make sure to properly activate biochar because charcoal alone may
Source: https://www.intechopen.com/chapters/72668
Figure 1.5: Importance of biochar
reduce the fertility of soil. One of the best things about biochar is that it can last in soil for
thousands of years.
Benefits provided by Biochar:
• Nutrient Retention
• Water Retention
• Habitat for Beneficial Microorganisms
• Increased Drainage
• Improved Aeration
• pH Buffer
• Makes Harmful Contaminants Inert
Worm Castings Worm Castings are generally more expensive than compost but are a more
concentrated and powerful amendment. They are packed full of beneficial microorganisms
and stimulate the germination of seeds!
Compost Tea Compost Tea is more of a microbial inoculate than a direct nutrient source. It can
be sprayed directly into your soil when preparing your bed to stimulate biological activity
and ensure the establishment of beneficial microbes.
There are countless recipes available to choose from but you can also just purchase it in many
garden centers.
pH Neutralization Soils that are too low or too high in pH can be detrimental to the growth of
plants. This is largely because soils with unfavorable pH reduce your plant’s ability to absorb
nutrients from the soul. This is particularly important in rainy or tropical climates where
soils are naturally acidic. There are a variety of options for neutralizing your soil’s pH.
pH Neutralizing Amendments:
• Pulverized Limestone
1.4 Soil Preparation
19
Source: https://pubs.acs.org/doi/10.1021/acs.est.2c02976
Figure 1.6: Integrating the biochar and bacteria in farming
•
•
•
•
Iron Sulfate
Aluminium Sulfate
Ash (not practical for highly acidic soils)
Sulfur (for Alkaline Souls)
5. Mulching Your Soil
Once soil has been properly loosened and amended it’s recommended to add a layer of mulch.
Typically something woody or slow to decompose is used to ensure it lasts throughout the
season. Avoid mulch that may contain the seeds of unfavorable weeds. Mulching is a process
where a layer of material is placed on the surface of soil. The purpose of mulching is to
conserve soil water. By creating a barrier between the soil and the atmosphere, mulching
reduces evaporation and helps the soil to retain moisture. In addition, mulching can also
reduce the amount of water that is lost through runoff. Benefits Of Mulch:
• Reduces Evaporation
• Protects Topsoil From UV Rays
• Feeds Soil Food Web
• Protects Soil from Erosion
• Promotes Beneficial Fungi
• Reduces Growth of Weeds
6. Cover Crops Cover Crops are an excellent option for highly deteriorated soils or for
individuals that don’t have the resources to properly amend their soil.
These are typically quick growing and nitrogen fixing crops that are incorporated into the soil
to improve nutrients content and add organic matter. Some cover crops can be implemented
along with your crop of value while others are planted independently.
Managing Your Soil For Long Term Health Once your soil has been prepared for planting it’s
important to continue managing it in a way that continues enhancing its fertility. Improper
management practices can greatly reduce the health of your soil. Best Management Practices
• Avoid Compacting Your Soil
Chapter 1. Concepts and Principles
20
Source: https://pubs.acs.org/doi/10.1021/acs.est.2c02976
Figure 1.7: Working of Mulching
•
•
•
•
•
•
Don’t Use Synthetic Fertilizers or Other Agrochemicals
Don’t Till or Disturb the Soil
Add Compost Regularly as a Top Dressing
Add more Mulch once the previous addition has decomposed.
Regularly Remove Unfavorable Weeds
Practice Crop Rotation
Regenerative Soil Management The most beautiful thing about organic soil management is that
soil can become more and more fertile after every season. This will not only mean the crops
are healthier but also need less work and resources as time goes on.
1.5
Organic Farming and Climate Change
Climate change leads to major insecurities for the world food supply. There is ample scientific
proof that organic farming can reduce greenhouse gas emissions and is a more resilient approach in
a changing climate. The improved water holding capacity of organic soils makes it easier to deal
with wet and dry intervals. Organic farmers can even have a positive climate impact, by sequestring
carbon in their soils.
Agriculture and climate
Agriculture produces 14% of all greenhouse gas emissions worldwide. In the whole agricultural
production chain, from fertilizer production to packaging, it produces 33% of all emissions. Organic
agriculture pays a positive part in this, because it lead to less emissions of greenhouse gases, less
energy expenditure and more carbon sequestration.
1.5.1
Organic Farming Reduces Greenhouse Gases
The fossil fuel-based fertilizers and most synthetic pesticides are prohibited in organic farming,
it has a significantly lower carbon footprint. The production of these farm chemicals are energy
intensive. Studies show that the elimination of synthetic nitrogen fertilizers alone, as is required
in organic systems, could lower direct global agricultural greenhouse gas emissions by about
20%. It is shown that organic farms use 45% less energy compared to conventional farms (while
1.6 Importance of Horticultural Crops
21
maintaining or even exceeding yields after a 5-year transition period.) Meanwhile, fumigant
pesticides - commonly used on crops like strawberries and injected into soil - emit nitrous oxide
(N2 O), the most potent greenhouse gas. Research indicates that one commonly used fumigant
pesticides, chloropicrin, can increase N2 O emissions by 700-800%. Two other fumigants (metam
sodium and dazomet) are also known to significantly increase N2 O output.
1.5.2
Organic Farming Improves Soil Carbon Sequestration
Soil-boosting practices that are the foundation of organic agriculture also help sequester more
carbon in soil compared to non-organic systems. Analyses have shown that organic agriculture
results in higher stable soil organic carbon and reduced nitrous oxide (N2 O) emissions when
compared to conventional farming. A recent review of almost 400 studies showed pesticide use was
associated with damage to soil invertebrates in more than 70% of the studies. Soil invertebrates are
critical to carbon sequestration, because they are responsible for the formation of soil components
that are essential to building soil organic carbon. In fact, estimates indicate that with worldwide
adoption of agroecological best management practices like diversified organic farming, soils could
actually absorb more carbon than the farming sector emits between 2020 and 2100.
1.5.3
Organic Farming Increases Resilience
Organic farms are required to build healthy soil and crops that make them better able to adapt in
a changing climate. First and foremost, organic farmers rely on composting, crop rotation, and
natural rather than fossil fuel-based inputs in order to maintain or improve soil health. As stewards
of healthy soil, organic farmers and ranchers can be a major force for climate mitigation. Organic
farming promotes resiliency by boosting soil’s ability to retain water and the natural nutrients found
in healthy soils. By increasing organic matter in soil continuously over time, organic agriculture
improves water percolation by 15-20%, replenishing groundwater and helping crops perform well
in extreme weather like drought and flooding. A decades-long organic farming trial found that
organic yields can be up to 40% higher than non-organic farms in drought years. By foregoing most
fossil fuel-based inputs, organic farmers are also more resilient and adaptable not only to stressors
related to climate change but also other disruptive global stressors.
1.6
Importance of Horticultural Crops
The term horticulture is derived from two Latin words hortus, meaning ‘garden’, and cultura
meaning ‘cultivation’. It refers to crops cultivated in an enclosure, that is, garden cultivation.
1.6.1
Features and importance
Horticulture crops perform a vital role in the Indian economy by generating employment, providing
raw material to various food processing industries, and higher farm profitability due to higher
production and export earnings from foreign exchange.
• Horticulture crops are a source of variability in farm produce and diets.
• They are a source of nutrients, vitamins, minerals, flavour, aroma, dietary fibres, etc.
• They contain health benefiting compounds and medicines.
• These crops have aesthetic value and protect the environment.
• The comparative production per unit area of horticultural crops is higher than field crops,
e.g., paddy crop gives a maximum yield of only 30 q/ha, while banana crop gives 300–450
q/ha and grapes 90–150 q/ha.
• Fruit and plantation crops can be cultivated in places where the slope of land is uneven or
undulating. Mango and cashew nut are cultivated on a large scale in hilly and hill back area
of the Konkan region.
The
crops are useful for cultivation in wasteland or poor quality soil.
•
Chapter 1. Concepts and Principles
22
•
•
•
Such crops are of high value, labour intensive and generate employment throughout the year.
Horticultural produce serves as raw material for various industries, such as processing,
pharmaceutical, perfumery and cosmetics, chemical, confectionery, oils and paints, etc.
They have national and international demand and are a good source of foreign exchange.
II
Module II
2
Horticulture Crops and Human Nutrition 25
2.1
2.2
2.3
2.4
Functions of fruits and vegetables in human body25
Selection of seeds, seedlings . . . . . . . . . . . . . . 26
Climatic condition of a crop . . . . . . . . . . . . . . . 27
Essential Plant Nutrients and their Deficiency Symptoms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Toxicities in Horticultural Crops . . . . . . . . . . . . . 30
Toxicity Problems . . . . . . . . . . . . . . . . . . . . . . . . 31
Toxicity Effects Due To Sprinkler Irrigation . . . . . 33
2.5
2.6
2.7
2. Horticulture Crops and Human Nutrition
Fruits and vegetables play an important role in balanced diet. These provide not only energy rich
food but also provide vital protective nutrients/elements and vitamins. Comparatively fruits and
vegetables are the cheapest source of natural nutritive foods. Since most of Indians are vegetarians,
the incorporation of horticulture produce in daily diet is essential for good health. With the growing
awareness and inclination towards vegetarianism worldwide the horticulture crops are gaining
tremendous importance.
2.1
Functions of fruits and vegetables in human body
1. Fruits and vegetables provide palatability, taste, improve appetite and provide fibre thereby the
constipation can be overcome.
2. They neutralize the acids produced during digestion of proteins and fatty acids.
3. They improve the general immunity of human body against diseases, deficiencies etc.
4. They are the important source of vitamins and minerals for used in several bio-chemical reactions
occur in body.
Fruits:- Fruits provide higher energy value per unit area compared to cereals. Some of the
essential nutrients provided by different fruits are:
Vitamins/ Minerals
Role in human body Source
Vitamin-A
1. Essential for growth and reproduction.
2. Helps in resistance to infections, increases longevity and decreases senility.
3. Deficiency causes, night blindness, xeropthalmia, retardation in growth, roughness in skin,
formation of stones in kidney. Eg. Mango, Papaya, Persimon, Dates, Jack fruit, Walnut, Oranges,
Passion fruit, Loquât etc.
Vitamin – B1
1. Essential for the maintains of good appetite and normal digestion.
2. Necessary for growth, fertility, lactation and for normal functioning of nervous system.
3. Deficiency causes beri-beri, paralysis, loss the sensitivity of skin, enlargement of heart, loss of
26
Chapter 2. Horticulture Crops and Human Nutrition
appetite and fall in body temperature. Eg. Walnut, Apricot, Apple, Banana, Grapefruit, Plum and
Almond.
Vitamin – B2
1. Important for growth, health of skin and for respiration in poorly vascularised tissue such as the
cornea.
2. Deficiency causes pellagra and alopecia, loss of appetite, loss of weight, sore throat, development
of cataract, swollen nose and baldness. Eg. Bael, Papaya, Litchi, Pomegranate, Wood apple and
Pineapple.
Vitamin – C
1. Deficiency causes scurvy, pain in joints, swelling of limbs, unhealthy gums, tooth decay, delay in
wound healing and rheumatism. Eg. Barbados cherry, Aonla, Guava, Lime, Lemon, Sweet oranges,
Ber, Pineapple and Pear.
Minerals are essential for the growth and development for the human body
Calcium Causes Rickets, Osteomalacia. Sitaphal, Ramphal, Fig, Phalsa, Citrus, Sapota, Grapes,
West Indian Cherry etc. Fruits are also a good source of energy eg. Avocado, Olive etc. They
are also a good source of enzymes which are helpful in metabolic activities leading to proper
digestion of food. Eg. Jamun and Papaya. All fruits have one or the other medicinal value. Regular
consumption of fruits reduces obesity, maintain health and increase the longevity of life.
2.2
Selection of seeds, seedlings
Seed is a fundamental requirement to grow most crops. In a broad sense, it is that part of a plant
which is used for propagation, planting, or regeneration purpose. Vegetable seeds are costly and
their wastage during sowing or handling increases the cost of cultivation. Healthy and good quality
seeds lead to a healthy crop. Hence, the selection of seeds is crucial. Only quality seeds that are
sown, according to the instructions set by the National Food Corporation, can give a desirable crop
yield. Seeds can be defined as a dormant embryo (micro- seedling), which develops into a plant
when subjected to required environmental conditions.
Home Crop Care
Seed Selection: A Step-by-Step Guide for Selecting Good-Quality Paddy Seeds and Their
Importance
In good quality seeds, the development of the root system will be more efficient that aids the
absorption of nutrients efficiently, and results in higher yield. Good quality seeds of improved
varieties ensure a higher yield.
Seed is the basic foundation of any crop. It must be grown, harvested, and processed correctly
for the best yield and quality results. Good quality seeds lead to lower seed rate, better emergence
(<70%), more uniformity, less replanting, and vigorous early growth which helps to increase
resistance to insects and diseases and decrease weeds.
In the following discussion importance of selecting good quality seeds and their selection is
taken up. Importance of good quality seeds
Quality seeds can ensure the genetic and physical purity of the crops.
They can give desired plant population.
They have the capacity to withstand adverse conditions.
The good quality seeds can produce vigorous, fast-growing seedlings and can resist pest and
disease incidence to a certain extent.
2.3 Climatic condition of a crop
27
Good quality seeds can ensure uniform growth and maturity.
In good quality seeds, the development of the root system will be more efficient that aids the
absorption of nutrients efficiently, and results in higher yield.
The good quality seeds will respond well to added fertilizer and other inputs
.
Good quality seeds of improved varieties ensure a higher yield of at least 10 – 12 %.
Seed quality parameters
A seed should be:
• genetically pure
• viable
• containing optimum moisture content
• free from mixture of other seeds
• healthy and free from infection or infestation
• intact, means, without any damage to any of its part
2.3
Climatic condition of a crop
An area’s climate affects the types of plants that can grow there. Plant growth is dependent on
precipitation and temperature. If the precipitation level is too high or too low or if the temperature
is too high or too low, plants may not grow well. Some climates are better for growing crops than
others. Favorable weather is essential for good harvests. Weather abnormalities like cyclones,
droughts, hailstorms, frost, high winds, extreme temperature and insufficient photosynthetic radiation etc., may generally lead to very low or even no yields. Hence, characterization of agro
climates is a prerequisite to know the potential of a region, especially under dry land conditions for
improving and stabilizing the productivity.
Climate is a key location-based factor in farming. Climatic conditions dictate not only whether
a plant will grow but also how it will grow. Yields, yield stability and quality are also closely
connected to the climate. The fact is, that with the exception of precipitation, climatic conditions
cannot be adjusted to suit agricultural requirements.
Low precipitation can at least partially be balanced out by irrigation, and too much rainfall can
be drained away. However, if precipitation remains low for longer periods of time, the decrease
in the groundwater level means that this will no longer work. In terms of how the climate affects
farming, the timing of precipitation plays a role in addition to the total annual rainfall. Large
amounts of rain over a short period of time are difficult for the ground to absorb, which is where
well-rooted, humus-rich soils have the advantage. Soil of this kind can absorb greater quantities
of water, which prevents nutrients from running off the surface. Increased soil aggregate stability
and water infiltration as a result of consistent vegetation are the right solution for an adapted water
management strategy when responding to the changing climate in farming.
Temperature is another key factor. In order to grow, plants require a specific temperature
range, and this can differ depending on their growth phase. The ideal temperature range for wheat
is between approx. 10°C and 25°C, for example. If the farming climate deviates too far from
this range, the crops can suffer from cold or heat stress. Vernalisation is an exception to this.
During early development, wheat requires temperatures below zero to form reproductive organs, for
instance. This effect can be problematic for sugar beet, however. After exposure to temperatures
below zero, bolting can occur. This is characterised by small beets with a correspondingly low yield.
In fruit farming, late frosts in springtime can also cause damage to buds, endangering yields. These
examples show that the reciprocal effects of the climate in agriculture are extremely complex.
Sunlight, nature’s driving force, is another important factor. Too much sun can scald leaves
and crops, inhibiting photosynthesis and restricting growth. The amount of biomass produced by
Chapter 2. Horticulture Crops and Human Nutrition
28
a crop depends on its growth rate and development time. The latter describes the time between
the plant emerging and it being harvested. Growth rate, on the other hand, denotes the quantity of
biomass produced per unit of time, and decreases as temperature increases. In the case of wheat, for
example, this means that farms with mild winters and relatively cool summers can achieve higher
yields than those with harsh winters and extremely hot summers.
For agriculture, any extreme weather conditions are problematic. Intense hail can completely
destroy foliage, as can heavy storms. Plants can snap or start to lodge during storms, preventing
them from thriving. These adverse climatic effects on farming can cause crops to fail and make
planning difficult.
Table 2.1: Types of climate in different regions of India
Region
Saurashtra, Kutch, Western Rajasthan, Bellary
(Karnataka), Anantapur (AP) Tirunelveli (TN)
The area from Kanyakumari in the south to Punjab in the north,
covering practically the whole of the Peninsula,
east of western ghats and Gaya-Jumai area in Bihar.
Northern parts of Punjab. Haryana, UP, Bihar, WB, Orissa, MP,
Vidarbhaand northern parts of AP and from Chennai to Nagapattanam (TN).
NE region, west coast and adjoining hills
2.4
Climate
Arid
Semi arid
Sub humid (Moist or Dry)
Pre-humid & humid zones
Essential Plant Nutrients and their Deficiency Symptoms
The normal green plant is autotrophic that means it can synthesise all its organic substances;
provided it is supplied with all the inorganic elements and growth under normal condition. The
nutrition of green plant is therefore, solely inorganic. It is, in fact, commonly called mineral
nutrition. Elements absorbed from the soil by the roots are generally known as Plant nutrients or
Mineral nutrients.
2.4.1
Role of essential elements in plants
It is useful to know the relative amounts of each nutrient that is needed by a crop in making fertilizer
recommendations. In addition, understanding plant functions and mobility within the plant should
prove useful in diagnosing nutrient deficiencies.Supply of sufficient and efficient balanced nutrition
is important for plants optimal growth. 17 elements are considered to be essential for plant nutrition.
Table 2.2: Types of climate in different regions of India
Nutrient
Carbon (C) Source: Air
Hydrogen (H) Source: Water
Oxygen (O) Source: Air/Water
Nitrogen (N) Source: Air/Soil
Phosphorus (P) Source: Soil
Potassium (K) Source: Soil
Calcium (Ca) Source: Soil
Sulphur (S) Source: Soil
Magnesium (Mg) Source: Soil
Iron (Fe) Source: Soil
Manganese (Mn) Source: Soil
Boron (B) Source: Soil
Chlorine (Cl) Source: Soil
Zinc (Zn) Source: Soil
Copper (Cu) Source: Soil
Molybdenum (Mo) Source: Soil
Nickel (Ni) Source: Soil
Functions
Constituent of carbohydrates; necessary for photosynthesis
Maintains osmotic balance; important in numerous biochemical reactions; constituent of carbohydrates
Constituent of carbohydrates, necessary for respiration
Constituent of proteins, chlorophyll and nucleic acids (affect growth and yield).
Constituent of many proteins, coenzymes, nucleic acids and metabolic substrates; important in energy transfer
Involved with photosynthesis, carbohydrate translocation, protein synthesis, etc.
A component of cell walls; plays a role in the structure and permeability of membranes
Important component of plant proteins
Enzyme activator, component of chlorophyll
Involved with chlorophyll synthesis and in enzymes for electron transfer
Controls several oxidation-reduction systems and photosynthesis
Believed to be important in sugar translocation and carbohydrate metabolism
Involved with oxygen production in photosynthesis
Involved with enzyme systems that regulate various metabolic activities
A catalyst for respiration; a component of various enzymes
Involved with nitrogen fixation and transforming nitrate to ammonium
Necessary for proper functioning of the enzyme, ureae, and found to be necessary in seed germination
2.4 Essential Plant Nutrients and their Deficiency Symptoms
29
Source: https://www.researchgate.net/figure/Essential-plant-nutrients
Figure 2.1: Essential Plant Nutrients
2.4.2
Plant Nutrients Deficiency Symptoms
Deficiency is the lack of something or the conditions which fail to meet the requirement. Like
humans and animals, plants also work in quite the same process. Yes, plants too need nutrients to
sustain themselves like every other living being. They get most of these nutrients from the soil.
But if the supply of this primary element is reduced or inadequate, plant growth is stunted and
retarded. The absence of any element necessary for the nourishment of that particular plant will
lead to morphological changes, this change is an indication of a deficiency.
Of course, if the deficient element is provided to the plant in good time, the symptoms of
deficiency disappear. However, if the process is delayed, eventually the plant will die.
2.4.2.1
Symptoms of Deficiency in Plants
As the supply of essential nutrients is reduced, then the plants exhibit a particular symptom which
differs from plant to plant.
In certain cases, If the deficiency elements are relatively mobile like Nitrogen, then the first
deficiency symptom appears in the older tissues of the plant and then followed by the younger
tissues. If the deficiency elements are relatively immobile and are not transported out of the mature
organs, then the first symptoms tend to appear in the younger tissues and then followed by the older
tissues.
The deficiency symptoms are varied and include, stunted plant growth, premature fall of leaves
and buds, yellowing of leaves, etc. These symptoms could be caused due to the lack of both
micronutrients and macronutrients in plants.
There are a few essential minerals required for plant’s growth and development. Hence, the
deficiency of such essential minerals, namely – iron, nitrogen, manganese, potassium, magnesium,
zinc, and calcium, results in deficiency symptoms.
Nutrient deficiency symptoms in plants can be confusing. Most of the plant nutrient deficiencies
look similar to symptoms of pest and disease incidence.
Nitrogen, phosphorus, and potassium are the three essential “macro” elements for the plant
30
Chapter 2. Horticulture Crops and Human Nutrition
growth so let us look at the importance of these nutrients and their deficiency symptoms, their
function and fertilizers to help correct deficiencies.
Source: https://blog.mydreamgarden.in/2020/11/24/
Figure 2.2: Deficiency Symptoms of Plant Nutrients
2.5
Toxicities in Horticultural Crops
The requirement of micronutrients is always in low amounts while their moderate decrease causes
the deficiency symptoms and a moderate increase causes toxicity. In other words, there is a narrow
range of concentration at which the elements are optimum. Any mineral ion concentration in
tissues that reduces the dry weight of tissues by about 10% is considered toxic. Such critical
concentrations vary widely among different micronutrients. The toxicity symptoms are difficult to
identify. Toxicity levels for any element also vary for different plants. Many a times, excess of an
element may inhibit the uptake of another element.
Nutrient toxicities in crops are more frequent for manganese (Mn) and boron (B) than for
other nutrients. Manganese toxicity is found on acid soils. It is important to know that manganese
competes with iron and magnesium for uptake and with magnesium for binding with enzymes.
Manganese also inhibits calcium translocation in shoot apex. Therefore, excess of manganese
may, induce deficiencies of iron, magnesium and calcium. Thus, what appears as symptoms of
manganese toxicity may actually be the deficiency symptoms of iron, magnesium and calcium.
Boron toxicities occur in irrigated regions where the well or irrigation waters are exceptionally
high in B. Most other nutrient toxicities occur when large amounts of nutrients in question have
been added in waste, e.g., sewage sludge. Crops grown near mines and smelters are prone to
2.6 Toxicity Problems
31
nutrient toxicities. Generally, the symptoms of toxicity in crops occur as burning, Chlorosis and
yellowing of leaves. Toxicities can result in decreased yield and/or impaired crop quality.
2.6
2.6.1
Toxicity Problems
Specific Ions and Their Effects
A toxicity problem is different from a salinity problem in that it occurs within the plant itself and
is not caused by a water short-age. Toxicity normally results when certain ions are taken up with
the soil-water and accumulate in the leaves during water transpiration to an extent that results in
damage to the plant. The degree of damage depends upon time, concentration, crop sensitivity
and crop water use, and if damage is severe enough, crop yield is reduced. The usual toxic ions in
irrigation water are chloride, sodium and boron. Damage can be caused by each, individually or in
combination.
Not all crops are equally sensitive to these toxic ions. Most annual crops are not sensitive at
the concentrations but the majority of tree crops and woody perennial-type plants are. Toxicity
symptoms, however, can appear on almost any crop if concentrations are high enough. Toxicity
often accompanies or complicates a salinity or infiltration problem although it may appear even
when salinity is low.
The toxic ions sodium and chloride can also be absorbed directly into the plant through
the leaves moistened during sprinkler irrigation. This occurs typically during periods of high
temperature and low humidity. The leaf absorption speeds the rate of accumulation of a toxic ion
and may be a primary source of the toxicity.
Many trace elements, in addition to sodium, chloride and boron, are toxic to plants at very low
concentrations. Fortunately most irrigation supplies contain very low concentrations of these trace
elements and are generally not a problem. These concentrations are based upon limits established
to protect the soil resource from contamination if continuously irrigated with water which contains
them.
2.6.1.1
Chloride
The most common toxicity is from chloride in the irrigation water. Chloride is not adsorbed or
held back by soils, therefore it moves readily with the soil-water, is taken up by the crop, moves in
the transpiration stream, and accumulates in the leaves. If the chloride concentration in the leaves
exceeds the tolerance of the crop, injury symptoms develop such as leaf burn or drying of leaf
tissue. Normally, plant injury occurs first at the leaf tips (which is common for chloride toxicity),
and progresses from the tip back along the edges as severity increases. Excessive necrosis (dead
tissue) is often accompanied by early leaf drop or defoliation. With sensitive crops, these symptoms
occur when leaves accumulate from 0.3 to 1.0 % chloride on a dry weight basis, but sensitivity
varies among these crops. Many tree crops, for example, begin to show injury above 0.3 % chloride
(dry weight).
Chemical analysis of plant tissue is commonly used to confirm a chloride toxicity. The part of
the plant generally used for analysis varies with the crop, depending upon which of the available
interpretative values is being followed. Leaf blades are most often used, but the petioles of some
crops (grapes) are sometimes used rather than leaves. For irrigated areas, the chloride uptake
depends not only on the water quality but also on the soil chloride, controlled by the amount of
leaching that has taken place and the ability of the crop to exclude chloride. Crop tolerances to
chloride are not nearly so well documented as crop tolerances to salinity. A chloride toxicity can
occur by direct leaf absorption through leaves wet during overhead sprinkler irrigation. This occurs
most frequently with the rotating type sprinkler heads.
32
2.6.1.2
Chapter 2. Horticulture Crops and Human Nutrition
Sodium
Sodium toxicity is not as easily diagnosed as chloride toxicity, but clear cases of the former have
been recorded as a result of relatively high sodium concentrations in the water (high Na or SAR).
Typical toxicity symptoms are leaf burn, scorch and dead tissue along the outside edges of leaves
in contrast to symptoms of chloride toxicity which normally occur initially at the extreme leaf
tip. An extended period of time (many days or weeks) is normally required before accumulation
reaches toxic concentrations. Symptoms appear first on the older leaves, starting at the outer edges
and, as the severity increases, move progressively inward between the veins toward the leaf centre.
Sensitive crops include deciduous fruits, nuts, citrus, avocados and beans, but there are many others.
For tree crops, sodium in the leaf tissue in excess of 0.25 to 0.50% (dry weight basis) is often
associated with sodium toxicity.
Leaf tissue analysis is commonly used to confirm or monitor sodium toxicity but a combination
of soil, water and plant tissue analyses greatly increases the probability of a correct diagnosis.
When using only leaf blade analysis to diagnose sodium toxicity, it is advisable to include analyses
of leaf blades from damaged trees as well as separate analyses from nearby undamaged ones for
comparative purposes.
Sodium toxicity is often modified or reduced if sufficient calcium is available in the soil.
Whether an indicated sodium toxicity is a simple one or is more complicated involving a possible
calcium deficiency or other interaction is presently being researched. Preliminary results indicate
that for at least a few annual crops, calcium deficiency rather than sodium toxicity may be occurring.
If confirmed, these crops should respond to calcium fertilization using material such as gypsum or
calcium nitrate.
The approximate levels of exchangeable sodium percentage (ESP) corresponding to the three
categories of tolerance are: sensitive less than 15 ESP; semi-tolerant 15–40 ESP; tolerant more than
40 ESP. Tolerance decreases in each column from top to bottom. The tolerances listed are relative
because, usually, nutritional factors and adverse soil conditions stunt growth before reaching these
levels. Soil with an ESP above 30 will usually have too poor physical structure for good crop
production. Tolerance in most instances were established by first stabilizing soil structure.
Particular care in assessment of a potential toxicity due to SAR or sodium is needed with high
SAR water because apparent toxic effects of sodium may be due to or complicated by poor water
infiltration. Only the more sensitive perennial crops have yield losses due to sodium if the physical
condition of the soil remains good enough to allow adequate infiltration. Several of the crops listed
as more tolerant do show fair growth when soil structure is maintained and, in general, these crops
can withstand higher ESP levels if the soil structure and aeration can be maintained, as in coarse
textured soils.
2.6.1.3
Boron
Boron, unlike sodium, is an essential element for plant growth. (Chloride is also essential but in
such small quantities that it is frequently classed non-essential.) Boron is needed in relatively small
amounts, however, and if present in amounts appreciably greater than needed, it becomes toxic. For
some crops, if 0.2 mg/l boron in water is essential, 1 to 2 mg/l may be toxic. Surface water rarely
contains enough boron to be toxic but well water or springs occasionally contain toxic amounts,
especially near geothermal areas and earthquake faults. Boron problems originating from the water
are probably more frequent than those originating in the soil. Boron toxicity can affect nearly all
crops but, like salinity, there is a wide range of tolerance among crops.
Boron toxicity symptoms normally show first on older leaves as a yellowing, spotting, or drying
of leaf tissue at the tips and edges. Drying and chlorosis often progress toward the centre between
the veins (interveinal) as more and more boron accumulates with time. On seriously affected trees,
such as almonds and other tree crops which do not show typical leaf symptoms, a gum or exudate
on limbs or trunk is often noticeable.
2.7 Toxicity Effects Due To Sprinkler Irrigation
33
Most crop toxicity symptoms occur after boron concentrations in leaf blades exceed 250–300
mg/kg (dry weight) but not all sensitive crops accumulate boron in leaf blades. For example, stone
fruits (peaches, plums, almonds, etc.), and pome fruits (apples, pears and others) are easily damaged
by boron but they do not accumulate sufficient boron in the leaf tissue for leaf analysis to be a
reliable diagnostic test. With these crops, boron excess must be confirmed from soil and water
analyses, tree symptoms and growth characteristics.
A wide range of crops was tested for boron tolerance by using sand-culture techniques. Previous
boron tolerance tables in general use have been based for the most part on these data. These tables
reflected boron tolerance at which toxicity symptoms were first observed and, depending on crop,
covered one to three seasons of irrigation. The original data from these early experiments, plus
data from many other sources, have recently been reviewed. The potentially toxic ions sodium,
chloride and boron can each be reduced by leaching in a manner similar to that for salinity, but
the depth of water required varies with the toxic ion and may in some cases become excessive. If
leaching becomes excessive, many growers change to a more tolerant crop. Increasing the leaching
or changing crops in an attempt to live with the higher levels of toxic ions may require extensive
changes in the farming system. In cases where the toxicity problem is not too severe, relatively
minor changes in farm cultural practices can minimize the impact. In a few cases, an alternative
water supply may be available to blend with a poorer supply to lower the hazard from the poorer
one.
2.7
Toxicity Effects Due To Sprinkler Irrigation
Overhead sprinkling of sensitive crops can cause toxicities not encountered when irrigating by
surface methods. The toxicity occurs due to excess quantities of sodium and chloride from the
irrigation water being absorbed through leaves wet by the sprinklers. Extreme cases have resulted
in severe leaf burn and defoliation. Absorption and toxicity occur mostly during periods of high
temperature and low humidity (<30 %), frequently aggravated by windy conditions. Rotating
sprinkler heads present the greatest risk. Between rotations water evaporates and the salts become
more concentrated in the shrinking volume of water. Slowly rotating sprinklers (less than 1
revolution per minute) cause alternate wetting and drying cycles; the slower the speed of rotation,
the greater the absorption. High frequency (near daily) spray irrigation has also created problems in
some cases.
The leaf burn and resulting crop damage seems to be due to uptake from the applied water of
either sodium or chloride. In some instances both sodium and chloride have been absorbed and both
accumulate. Toxicity to sensitive crops occurs at relatively low sodium or chloride concentrations
(>3 me/l) and, in general, crops sensitive to sodium or chloride are thought to be most sensitive to
foliar absorption. Most annual crops are not sensitive but they will be damaged if concentrations
are high enough. Crop tolerances to sodium and chloride in sprinkler-applied irrigation water
are not well established due to limited data and the pronounced influence of climatic conditions.
They should be used as a first approximation of the potential hazard and any situation which
approaches the sodium or chloride values given should be further evaluated by field testing before
full implementation of the application system.
2.7.1
Prevention of toxicity
1. With the exception of Mo, toxicity of other nutrients can be reduced by liming.
2. Following recommended rates of fertilizers and the safe and controlled use of waste materials,
such as sewage sludge and coal fly ash, should reduce metal loading and nutrient toxicity in
crops.
3. Use of crop species and genotypes less susceptible to toxicity are recommended where
toxicity is suspected.
34
Chapter 2. Horticulture Crops and Human Nutrition
4. Provided sufficient drainage because availability of nutrients like Fe and Mn is increases up
to toxicity level under water logged condition.
5. Ground water must be monitored regularly, if content of B and Cl is too high stop to applied
water or applied with dilution.
6. Addition of sufficient amount of organic matter binds some of the toxic elements.
7. Ploughing in dry soil so increase the infiltration rate and leach the toxic element with rain
water.
III
Module III
3
Organic Manures and Compost . . . . . . 37
3.1
3.2
3.3
3.4
Organic Manures . . .
Inorganic Manures . .
Compost Production
Vermi-compost . . . .
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43
3. Organic Manures and Compost
3.1
Organic Manures
Manures are plant and animal wastes that are used as sources of plant nutrients. They release
nutrients after their decomposition. The art of collecting and using wastes from animal, human
and vegetable sources for improving crop productivity is as old as agriculture. Manures are the
organic materials derived from animal, human and plant residues which contain plant nutrients in
complex organic forms. Naturally occurring or synthetic chemicals containing plant nutrients are
called fertilizers. Manures with low nutrient, content per unit quantity have longer residual effect
besides improving soil physical properties compared to fertilizer with high nutrient content. Major
sources of manures are:
• Cattle shed wastes-dung, urine and slurry from biogas plants
• Human habitation wastes-night soil, human urine, town refuse, sewage, sludge and sullage
Poultry Jitter, droppings of sheep and goat
• Slaughterhouse wastes-bone meal, meat meal, blood meal, horn and hoof meal, Fish wastes
Byproducts of agro industries-oil cakes, bagasse and press mud, fruit and vegetable processing
wastes etc
• Crop wastes-sugarcane trash, stubbles and other related material
• Water hyacinth, weeds and tank silt, and
• Green manure crops and green leaf manuring material
Manures can also be grouped, into bulky organic manures and concentrated organic manures
based on concentration of the nutrients.
3.1.1
Bulky organic manures
Bulky organic manures contain small percentage of nutrients and they are applied in large quantities.
Farmyard manure, compost and green-manure are the most important and widely used bulky organic
manures. Use of bulky organic manures has several advantages:
• They supply plant nutrients including micronutrients
• They improve soil physical properties like structure, water holding capacity etc.,
• They increase the availability of nutrients
• Carbon dioxide released during decomposition acts as a CO2 fertilizer and
Chapter 3. Organic Manures and Compost
38
Source: https://doraagri.com/what-is-organic-fertilizer-for-plants/
Figure 3.1: Organic Fertilizers
•
3.1.2
Plant parasitic nematodes and fungi are controlled to some extent by altering the balance of
microorganisms in the soil.
Farmyard manure
Farmyard manure refers to the decomposed mixture of dung and urine of farm animals along
with litter and left over material from roughages or fodder fed to the cattle. On an average well
decomposed farmyard manure contains 0.5 % N, 0.2 % P2O5 and .0.5 % K2O.The present method
of preparing farmyard manure by the farmers is defective. Urine, which is wasted, contains one
per cent nitrogen and 1.35 per cent potassium. Nitrogen present in urine is mostly in the form
of urea which is subjected to volatilization losses. Even during storage, nutrients are lost due to
leaching and volatilization. However, it is practically impossible to avoid losses altogether, but can
be reduced by following improved method of preparation of farmyard manure.
Trenches of size 6 m to 7.5 m length, 1.5 m to 2.0 m width and 1.0 m deep are dug.All available
litter and refuse is mixed with soil and spread in the shed so as to absorb urine. The next morning,
urine soaked refuse along with dung is collected and placed in the trench. A section of the trench
from one end should be taken up for filling with daily collection. When the section is filled up
to a height of 45 cm to 60 cm above the ground level, the top of the heap is made into a dome
and plastered with cow dung earth slurry. The process is continued and when the first trench is
completely filled, second trench is prepared.
The manure becomes ready for use in about four to five months after plastering. If urine is not
collected in the bedding, it can be collected along with washings of the cattle shed in a cemented
pit from which it is later added to the farmyard manure pit. Chemical preservatives can also be
3.1 Organic Manures
39
used to reduce losses and enrich farmyard manure. The commonly used chemicals are gypsum and
superphosphate. Gypsum is spread in the cattle shed which absorbs urine and prevents volatilization
loss of urea present in the urine and also adds calcium and sulphur. Superphosphate also acts
similarly in reducing losses and also increases phosphorus content.
Partially rotten farmyard manure has to be applied three to four weeks before sowing while
well rotten manure can be applied immediately before sowing. Generally 10 to 20 t/ha is applied,
but more than 20 t/ha is applied to fodder grasses and vegetables. In such cases farmyard manure
should be applied at least 15 days in advance to avoid immobilization of nitrogen. The existing
practice of leaving manure in small heaps scattered in the field for a very long period leads toloss
of nutrients. These losses can be reduced by spreading the manure and incorporating by ploughing
immediately after application.
Vegetable crops like potato, tomato, sweet-potato, carrot, raddish, onion etc., respond well to
the farmyard manure. The other responsive crops are sugarcane, rice, napier grass and orchard
crops like oranges, banana, mango and plantation crop like coconut.
The entire amount of nutrients present in farmyard manure is not available immediately. About
30 % of nitrogen, 60 to 70 % of phosphorus and 70 % of potassium are available to the first crop.
Sheep and Goat Manure
The droppings of sheep and goats contain higher nutrients than farmyard manure and compost.
On an average, the manure contains 3 % N, 1 % P2O5 and 2 % K2O.It is applied to the field in
two ways. The sweeping of sheep or goat sheds are placed in pits for decomposition and it is
applied later to the field. The nutrients present in the urine are wasted in this method. The second
method is sheep penning, wherein sheep and goats are kept overnight in the field and urine and fecal
matter added to the soil is incorporated to a shallow depth by working blade harrow or cultivator or
cultivator.
3.1.3
Poultry Manure
The excreta of birds ferment very quickly. If left exposed, 50 % of its nitrogen is lost within 30
days. Poultry manure contains higher nitrogen and phosphorus compared to other bulky organic
manures. The average nutrient content is 3.03 % N; 2.63 % P2O5 and 1.4 % K2O.
3.1.4
Concentrated organic manures
Concentrated organic manures have higher nutrient content than bulky organic manure. The
important concentrated organic manures are oilcakes, blood meal, fish manure etc. These are
also known as organic nitrogen fertilizer. Before their organic nitrogen is used by the crops, it is
converted through bacterial action into readily usable ammoniacal nitrogen and nitrate nitrogen.
These organic fertilizers are, therefore, relatively slow acting, but they supply available nitrogen for
a longer period.
3.1.5
Oil cakes
After oil is extracted from oilseeds, the remaining solid portion is dried as cake which can, be used
as manure. The oil cakes are of two types:
Edible oil cakes which can be safely fed to livestock; e.g.: Groundnut cake, Coconut cake etc.,
and Non edible oil cakes which are not fit for feeding livestock; e.g.: Castor cake, Neem cake,
Mahua cake etc.,
Both edible and non-edible oil cakes can be used as manures. However, edible oil cakes
are fed to cattle and non-edible oil cakes are used as manures especially for horticultural crops.
Nutrients present in oil cakes, after mineralization, are made available to crops 7 to 10 days after
application. Oilcakes need to be well powdered before application for even distribution and quicker
decomposition.
Chapter 3. Organic Manures and Compost
40
3.2
Inorganic Manures
Many sources of fertilizer exist, both natural and industrially produced.[1] For most modern
agricultural practices, fertilization focuses on three main macro nutrients: nitrogen (N), phosphorus
(P), and potassium (K) with occasional addition of supplements like rock flour for micronutrients.
Farmers apply these fertilizers in a variety of ways: through dry or pelletized or liquid application
processes, using large agricultural equipment or hand-tool methods.
Inorganic fertilizers, commonly referred to as synthetic fertilizers, are prepared for readymade
use in plants. These artificial fertilizers are available in single- or multi-nutrient formulations. There
are 16 nutrients that are considered to be crucial for plant development. They can be divided into
primary nutrients and secondary nutrients. The three most crucial fundamental elements found in
modern chemical fertilizers are nitrogen, phosphorus, and potassium. Due to the increased risk of
the plant burning from an excessive application, it is crucial to take the concentration into account
while applying inorganic fertilizers. The quick release of nutrients that penetrate deeply into the
soil and water yet are inaccessible to plants is another drawback of inorganic fertilizer. Inorganic
fertilizer has several benefits, like being less expensive in the long run and adding less to the ground.
It is also simpler to use and prepare.
Source: https://prepp.in/news/e-492-organic-vs-inorganic-fertilizers-agriculture-notes-Inorganic
Figure 3.2: Inorganic Fertilizers
Let’s understand the difference between Organic and Inorganic Manures / Fertilizers:
3.3
Compost Production
Compost is a soil amendment produced through the metabolism of an organic substrate—a surface
on which organisms grow—by aerobic (oxygen-requiring) microbes under controlled conditions.
Composting is an ancient agricultural technology going back to biblical times that still has important
applications in modern agriculture. Recent years have seen a resurgence of interest in compost
for modern cropping systems. In organic cropping systems, compost provides a primary source
of nutrients for the crop. In conventional cropping systems, compost provides a supplementary
nitrogen source that compliments fertilizer nitrogen to provide a more sustainable farming system.
3.3 Compost Production
41
Table 3.1: Difference between Organic and Inorganic Manures / Fertilizers
Description
Physical Properties
Chemical Properties
Biological Activities
Use
Application
3.3.1
Organic Manure
Improves the Soil Structure
Improved Water Holding Capacity
Soil becomes more permeable
Improves Drainage in the Soil
Prevents Soil Erosion
Decreases water Evaporation
Slow release of Nutrients
Decreases leaching of nutrients from soil
Supplies micronutrients
Doesn’t produce acidity or alkalinity in the soil
Upon Decomposition produces organic acids: to dissolve minerals
Increases the growth of microorganisms like earthworms
Usually applied 15-20 days before the crop is sown
Not used in liquid form
Used in huge quantity
Organic manures are incorporated in soil
By hand
In-Organic Manures
No effect on soil structure
No water holding capacity
No effect of fertilizer on Permeability
No effect
No effect
No effect
Fast release of nutrients
No such effects
No Micronutrients supply
Sodium products produce acidity and alkalinity in the soil
No such effects
Slightly helps in the growth of microorganisms
Nitrogen fertilizer is applied immediately before sowing.
Used as foliar spray
Used in Small Quantity
It is also incorporated may be used as top dressing
By hand or special equipment
Benefits of composting
Compost use in field crops should be part of any long-term crop management plan. Composting
also helps dairies manage manure, it has agronomic benefits, it controls plant diseases, and adds
nutrients to the soil.
3.3.2
Nutrient composition of compost
It is important to know the nutrient composition of the compost being used since nutrient concentrations can vary considerably, especially for phosphorous and potassium. It is necessary to perform
a lab analysis for compost nutrient content to determine the amount of nitrogen, phosphorous,
potassium, carbon, and salts (it can be more complex including heavy metals and other components,
if necessary). Nitrogen content will vary according to the carbon-to-nitrogen ratio of the compost
feedstuff. If the ratio is poor on the carbon side, then the nitrogen in the compost will be lower.
After determining the content of several compost samples, the sampling frequency can be reduced
if the same feedstock is always being used. Nitrogen concentration tends to be more uniform.
Much of the nitrogen in compost is present in an organic form that is not readily available to plants.
Organic nitrogen is converted to inorganic by soil organisms in the mineralization process. Compost
nitrogen mineralization is 8% to 12% per year. Mineralization is a complex process and much work
remains to be done to determine how organisms of the soil foodweb behave differently in different
cropping systems.
3.3.3
Composting process – 3 phases
In the composting process, microorganisms utilize an organic substrate—such as manure, bedding,
grass clippings, municipal waste—as a food source. Microbes harness the energy contained in the
chemical bonds of the substrate in a process that requires oxygen and water. Heat and CO2 result,
and the remaining carbon skeletons are recalcitrant humic substances that are largely responsible
for the soil-amending ability of compost.
3.3.3.1
Initial mesophilic phase
In the initial or mesophilic phase of composting, the population of microbes increases exponentially
as readily available food sources of the substrate are metabolized. Temperatures of the compost
pile gradually rise from ambient to more than 100°F.
42
3.3.3.2
Chapter 3. Organic Manures and Compost
Second thermophilic phase
The next phase, thermophilic, occurs during the next week or two when temperatures may reach
140°F to 160°F. Microbes that can endure the high temperatures of the pile are also responsible for
decomposing more resistant parts of the substrate.
It is important to have adequate moisture and oxygen during this stage to maintain the high
population of microbes in the compost pile. During this stage, all of the easily decomposable
material will be used up, leaving only the most resistant materials.
3.3.3.3
Final (second mesophilic) phase
This is a curing period where composting slows down and the compost becomes relatively stable.
During this stage, soil microbes recolonize the pile, and the formation of humic substances increases.
The presence of soil microbes is important because they are responsible for the disease- suppressive
qualities of compost. The curing stage begins when the compost pile fails to reheat after turning
and ends when the pile approaches ambient temperature.
3.3.3.4
Compost pile management
To produce a good yield of high quality compost, several variables must be managed to provide
for needs of composting microbes. The most important variables are substrate, oxygen content,
moisture, and temperature.
3.3.3.5
Substrate
Organic materials must provide the nutrients needed for microbial growth. One of the most
important factors is the ratio of carbon to nitrogen (C:N). Carbon and nitrogen are both needed by
microbes in the composting process. A high C:N ratio (too much carbon) means that there is not
sufficient N to fulfill the microbes’ needs. A low ratio (too much nitrogen) means that is more N
microbes can decompose. The compost pile will have a bad odor.
Optimum is a C:N ratio of 25:1 to 30:1, but composting has been done in a range of 20:1 to 40:1. At
a low C:N, the available carbon is consumed before stabilization of the nitrogen occurs, increasing
the potential for loss into the atmosphere or soil. At a high C:N, a longer composting time is
required without the addition of an N source. In addition to the C:N, the quality of the substrate
in terms of chemical and physical composition is important. For example, carbon in compounds
resistant to microbial attack (such as lignin—the chief component of wood) will be composted
at a much slower rate than carbon of simple sugars. Substrate physical properties that affect
composting include porosity, structure, texture, and particle size. These physical characteristics
affect composting through their effects on oxygen availability and surface area for microbes.
• Porosity measures air space and is determined by particle size, particle size uniformity, and
air space continuity. Large, relatively uniform particles produce a high porosity, which aids
in aeration of the pile.
• Structure refers to particle rigidity. Rigid particles resist the tendency for settling that causes
loss of porosity during the composting process.
Texture
refers to the available surface area for microbial action. This is important because
•
most microbial activity occurs in a thin layer of water surrounding the particles. As composting proceeds, the microbes work their way inward. Thus, composting occurs much more
rapidly as the surface area of substrate is increased. However, there is a compromise because
decreasing particle size to improve texture decreases porosity which, in turn, restricts air flow
in the compost pile.
Oxygen content: Composting is an aerobic process because microbes involved require oxygen to
live. Thus, it is necessary to provide an adequate supply of oxygen. This is accomplished by turning
the pile of compost, using a machine or by hand. The oxygen content of the pore space in the pile
needs to be at least 5%. Oxygen concentration may be monitored with an oxygen meter used for
3.4 Vermi-compost
43
compost. Also, regular turning assures oxygen levels without need to measure it. If anaerobic
(low oxygen) conditions develop, a different microbial community will inhabit the compost pile,
reducing the efficiency of process and producing undesirable chemical compounds.
Moisture: Moisture should be maintained between 40% and 65%—sufficient water to meet
microbial needs without restricting air movement in the pores. Use a simple “feel” test to judge
moisture level in the compost pile. If water can be squeezed out by hand, the pile is too wet. If a
handful does not feel moist, the pile is too dry. Adequate moisture is the most common limiting
compost process. Moisture can be added at the moment of turning the pile. Adding moisture with a
hose to a windrow or pile is difficult because compost has insulating properties, so water will hit
the surface of the compost pile and most will run down off the pile.
Temperature: Composting can occur at moderate (mesophilic) temperatures of 10°C to 40°C or
high (thermophilic) temperatures of 40° to 65°C. It is common for compost piles to be managed for
the activity of thermophilic microbes because higher temperatures are needed to kill pathogens and
weed seeds. At temperatures above 71°C, even thermophilic microbes suffer and composting slows,
causing the quality of the compost to decline. Temperature in the pile can be regulated by turning
the pile or by the forced aeration system.
3.4
Vermi-compost
Vermicomposting Definition
“Vermicomposting is a process in which the earthworms convert the organic waste into manure
rich in high nutritional content.”
What is Vermicomposting?
Vermicomposting is the scientific method of making compost, by using earthworms. They are
commonly found living in soil, feeding on biomass and excreting it in a digested form.
Vermiculture means “worm-farming”. Earthworms feed on the organic waste materials and give
out excreta in the form of “vermicasts” that are rich in nitrates and minerals such as phosphorus,
magnesium, calcium and potassium. These are used as fertilizers and enhance soil quality.
Vermicomposting comprises two methods:
• Bed Method: This is an easy method in which beds of organic matter are prepared.
• Pit Method: In this method, the organic matter is collected in cemented pits. However, this
method is not prominent as it involves problems of poor aeration and waterlogging.
3.4.1
Process of Vermicomposting
The entire process of vermicomposting is mentioned below:
Aim To prepare vermicompost using earthworms and other biodegradable wastes.
Principle This process is mainly required to add nutrients to the soil. Compost is a natural fertilizer
that allows an easy flow of water to the growing plants. The earthworms are mainly used in this
process as they eat the organic matter and produce castings through their digestive systems. The
nutrients profile of vermicomposts are:
• 1.6 % of Nitrogen.
• 0.7 % of Phosphorus.
• 0.8 % of Potassium.
• 0.5 % of Calcium.
• 0.2 % of Magnesium.
• 175 ppm of Iron.
• 96.5 ppm of Manganese.
• 24.5 ppm of Zinc.
Materials Required
• Water.
Chapter 3. Organic Manures and Compost
44
•
•
•
•
•
•
•
•
•
Cow dung.
Thatch Roof.
Soil or Sand.
Gunny bags.
Earthworms.
Weed biomass
A large bin (plastic or cemented tank).
Dry straw and leaves collected from paddy fields.
Biodegradable wastes collected from fields and kitchen.
Figure 3.3: Vermi Composting
Procedure
To prepare compost, either a plastic or a concrete tank can be used. The size of the tank depends
upon the availability of raw materials. Collect the biomass and place it under the sun for about 8-12
days. Now chop it to the required size using the cutter.
Prepare a cow dung slurry and sprinkle it on the heap for quick decomposition. Add a layer (2–3
inch) of soil or sand at the bottom of the tank. Now prepare fine bedding by adding partially
decomposed cow dung, dried leaves and other biodegradable wastes collected from fields and
kitchen. Distribute them evenly on the sand layer.
Continue adding both the chopped bio-waste and partially decomposed cow dung layer-wise into
the tank up to a depth of 0.5-1.0 ft. After adding all the bio-wastes, release the earthworm species
over the mixture and cover the compost mixture with dry straw or gunny bags. Sprinkle water on a
regular basis to maintain the moisture content of the compost.
Cover the tank with a thatch roof to prevent the entry of ants, lizards, mouse, snakes, etc. and
protect the compost from rainwater and direct sunshine.
Have a frequent check to avoid the compost from overheating. Maintain proper moisture and
temperature.
After the 24th day, around 4000 to 5000 new worms are introduced and the entire raw material is
turned into the vermicompost.
3.4.1.1
Advantages of Vermicomposting
The major benefits of vermicomposting are:
• Develops roots of the plants.
• Improves the physical structure of the soil.
• Vermicomposting increases the fertility and water-resistance of the soil.
• Helps in germination, plant growth, and crop yield.
• Nurtures soil with plant growth hormones such as auxins, gibberellic acid, etc.
3.4 Vermi-compost
3.4.1.2
45
Disadvantages of Vermicomposting
Following are the important disadvantages of vermicomposting:
• It is a time-consuming process and takes as long as six months to convert the organic matter
into usable forms.
• It releases a very foul odour.
• Vermicomposting is high maintenance. The feed has to be added periodically and care should
be taken that the worms are not flooded with too much to eat.
The
bin should not be too dry or too wet. The moisture levels need to be monitored
•
periodically.
• They nurture the growth of pests and pathogens such as fruit flies, centipede and flies.
Vermicomposting turns the kitchen waste and other green waste into dark, nutrient-rich soil. Due to
the presence of microorganisms, it maintains healthy soil.
Vermicomposting is an eco-friendly process that recycles organic waste into compost and
produces valuable nutrients.
IV
Module IV
4
Pest & Disease Management and Harvesting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
4.1
4.2
Pest & Disease Management . . . . . . . . . . . . . 49
Organic Methods of Pest and Disease Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Weed Management . . . . . . . . . . . . . . . . . . . . 55
Mechanical Weed Control . . . . . . . . . . . . . . . 59
Thermal Weed Control . . . . . . . . . . . . . . . . . . . 59
Biological Weed Control . . . . . . . . . . . . . . . . . 60
Harvesting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
POST HARVEST MANAGEMENT . . . . . . . . . . . . . . 64
Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Handling and Storage of Horticultural Crops . . . 67
4.3
4.4
4.5
4.6
4.7
4.8
4.9
4.10
4. Pest & Disease Management and
Harvesting
4.1
Pest & Disease Management
When we are choosing organic farming pest management is always a concern. Pest management is
done by using biological control, natural or organic pesticide. For weed control (common problem
of farmers, gardeners) is done by using cultural control.
The goal of pest management organically is limit or end the pest infestation from field without
harming the crop, plant or ecosystem or environment. Some disease and pest limit the use of
resources. So this is very important to choose the method that right choice for your crop.
The successful IPM (Integrated Pest Management) program or the four principal that organic
farming pest management based on is prevention, avoidance, monitoring, and suppression.
Crop protection and identification of pests in organic farming
Crop protection is work as the master step whereas pest identification is the slave step. To protect
the crop we need to find out about pest, insect, and their natural enemies.
Monitoring of field, pest, and damage pest or insect cause on regular basis can act as a key
term in pest identification. It can also work as early detection of the problem that will come in near
future.
There are many factors at play for a successful agricultural yield like the soil health, water
management, crop health, nutrient management etc. These factors could only be useful if there is a
proper system of protection from pests and diseases.
Health is Wealth, this line is commonly referred to the health of human beings but why don’t
this can be applied to agriculture as well? Agriculture could be successfully completed if there
exists a proper system of ensuring that the crops are safe from any external harm. What is the use of
an efficient water management system, nutrient management and using good quality seeds if there
isn’t a proper way to ensure the safety of crops from pests and diseases which could eat up the fruits
of hard work? This is why pest and disease management becomes a crucial step for agriculture.
Here the study of the Management of pests and diseases is taken up.
But before that let us understand the importance of management of these and its types.
Importance of pest and disease management in the organic farming
Pests and Diseases are some of the major hurdles for the cultivation of crops. If ignored it can lead
to catastrophic consequences in which significant economic losses can be incurred not only by the
50
Chapter 4. Pest & Disease Management and Harvesting
individual farmers, but also by the agriculture sector as a whole. Since the dawn of civilization,
humans have been in search of various ways in which pests and diseases could be controlled or
minimized so that it does not affect the total crop yield. There are several instances written in
history where uncontrolled pests and plant diseases have wreaked havoc in a particular place leaving
the settlers there in utter chaos.
4.1.0.1
Types of Pests and Diseases
Pest and diseases prevalent in the crop fields have posed a major barrier for the cultivation of
healthy and surplus crops. It poses a major challenge not only for the farmers but also for all the
scientists and employees related to the agriculture sector. Various crop protection systems have
been developed for the prevention and control of pests which otherwise have the capability to
annihilate an entire output of the farms, resulting in very heavy losses for the farmers.
Pests can be defined as, “Any organism or plant that poses a serious threat towards the humans
and human concerned things.” This term is specially used for such organisms that damage crops,
livestock and forestry.
But before that let us understand the importance of management of these and its types.
4.1.0.2
Importance of pest and disease management in the organic farming
Pests and Diseases are some of the major hurdles for the cultivation of crops. If ignored it can lead
to catastrophic consequences in which significant economic losses can be incurred not only by the
individual farmers, but also by the agriculture sector as a whole. Since the dawn of civilization,
humans have been in search of various ways in which pests and diseases could be controlled or
minimized so that it does not affect the total crop yield. There are several instances written in
history where uncontrolled pests and plant diseases have wreaked havoc in a particular place leaving
the settlers there in utter chaos.
Pests reduce crop productivity in various ways classified by the impacts they cause, they can be
divided into various types:
• Stand reducers (damping off pathogens)
• Photosynthetic rate reducers (fungi, bacteria, viruses)
• Leaf senescence accelerators (pathogens)
• Light stealers (weeds, some pathogens)
• Assimilate sappers (nematodes, sucking arthropods)
• Tissue consumers (chewing animals, necrotrophic pathogens)
Without proper preventive measures, pesticides, host plant resistance and other non-chemical
controls, 70% of crops could have been lost due to pests. Weeds produce the highest potential loss
(30%) with animal pests and pathogens being less important (23 and 17 % respectively).
A plant disease is a dynamic process where living and non-living entities interfere with the
normal functions of a plant and prevent it from functioning to its maximum potential. Pathogens
like fungi, nematodes, viruses, viroid, nematodes or flowering plants can cause several infectious
diseases. An infectious disease is capable of reproducing within or to other non-infectious plants.
Abiotic problems can also cause several plant diseases. Several abiotic factors like irradiation,
water, temperature and nutrients can be a major factor. Extremes of temperatures, disadvantageous
relationships between moisture and oxygen, toxic substances in soil and atmosphere and excess
or deficiency of an essential mineral can be the cause of abiotic problems. These diseases are
non-transmissible like the diseases caused by pathogenic organisms. Many valuable crops are
extremely vulnerable to diseases and would have had a very tough time in the wild without the
proper intervention by the human hands.
Some examples of pathogenic diseases are:
1. Bacterial – Aster yellow, bacterial wilt, canker, crown gall, rot (subtypes – basal rot), scab,
blight (subtypes – fire blight, rice bacterial blight)
4.1 Pest & Disease Management
51
2. Fungal – Anthracnose, black knot, canker, clubroot, damping off, dutch elm disease, ergot,
leaf blister, oak, scab (subtypes – apple scab), smut (subtypes – bunt, corn smut).
3. Viral – Curly top, mosaic, psoriasis, spotted wilt.
4.1.0.3
Pests and diseases management in the organic farming
Organic farming tends to tolerate some pest populations while taking a longer term approach,
allowing a certain level of pests and certain beneficial microorganisms can be very beneficial for
organic farming. Pests and diseases are not a significant problem in the organic systems but, when
left uncontrolled could incur a major damage on the crops. Pests do not actively result in damage
or yield losses but after a certain threshold, they can produce huge economic losses.
Here we will discuss some major management practices for controlling pests & diseases which are:
Effective planning An effective plan for the control of disease and pest management must be
created which must include the entire farm operation and with all the information available
some basic components for any strategy that should be included are insect and disease
avoidance, managing the growth environment etc.
Crop Rotation Crop rotation is found to be one of the most effective and useful techniques that
are used throughout the world to minimize the pest problems.
In order to execute a successful crop rotation to reduce the pest in a crop field some points
need to be followed:
• Incorporating green manure crops.
• Managing a frequency in which crops are grown within a rotation.
• Rotating early seeded, late seeded and fall-seeded crops.
• Rotating between various crop types, such as annual, winter , perennial, grass and
broadleaf crops.
Seed Quality One of the most efficient means to prevent diseases in the plants is the use of highquality seeds. The seed should be free from smut, ergot bodies and other sclerotia, and
free of kernels showing symp Fusarium head blight infection. Seed analysis by any reputed
laboratory can be very helpful in determining specific diseases prevalent seed supply.
Weed management Weed management is one of the most crucial aspects of pests and diseases
management in organic farming. Even though weeds need to be regulated in a farm field to
control their destructive side effects on the crop yield, their complete annihilation from the
farm field may not be the best solution as the weeds provide shelter for the beneficial insects.
Parasitic wasps, a kind of beneficial insects, are attracted to weeds with small flowers. Each
field situation should be dealt with in an individual manner. The amount of weed present in
farmland should be observed very carefully so that its positive effects can be enhanced and
negative effects be reduced.
Forecasting Farmers should carefully listen and observe the forecast about the various pests and
disease infestations for crops each year. Agro-meteorological warnings and forecasts can help
them in this way. Keeping oneself updated with the local news can be extremely beneficial in
terms of taking measures beforehand to deal with pest infestations.
Tillage Tillage can be properly timed before seeding, after harvesting and during summer to reduce
populations of insect pests such as cutworms and grasshoppers that spend a part of their
lifecycle in the soil or stubble. Tillage can be a very helpful method to minimize pests in the
farms by starving insects during the spring or during fallow or prevent adults from laying
eggs in the soil.
Seeding date Planting the crops should be well planned beforehand so that the most vulnerable
time of the plant growth does not correspond to the peak in the pest cycles. Early seeding
reduces crop damages caused by grasshoppers, aphids in cereal crops, wheat midge in spring
wheat, barley yellow dwarf virus in barley and wheat, powdery mildew in peas and pasmo
in flax. Delayed seeding can have a beneficial impact in terms of reducing wireworms,
52
Chapter 4. Pest & Disease Management and Harvesting
cutworms in the cereal crops, hessian fly in the winter wheat, barley thrips ascochyta in the
lentils etc.
Intercropping The practice of intercropping where two or more crops are grown at the same time
can significantly reduce the pest problems by making it very difficult for the pests to find
a host crop. This technique also provides a habitat for the beneficial organism to thrive.
Strip-cropping row crops with perennial crops often leads to better pest control.
Some other preventive measures are as follows:
• Resistant varieties of crops are ro be selected which could adapt to the local environmental
conditions
The
seeds should be properly checked with pathogens or weeds and it should be taken from
•
safe sources
• Proper Nutrient should be managed with an increase in organic matter
• Water should be properly managed and suitable soil cultivation methods should be applied
• Planting time and Spacing of the crops should be monitored, with proper sanitation measures
• Promote and Conserve natural enemies of pests such as fungi, bacteria, insect predators and
insect parasitoids by minimizing the use of natural pesticides
• Enhance Floral diversity within the farm and also along the boundaries of the farm by
applying hedges, beetle banks, flower strips and companion
• plants which would attract the natural enemies of the pests
• Pests can be controlled by mechanical means as well by applying light traps, colour and
water traps, yellow sticky traps, fruit bagging
• Sulphur and Bordeaux mixture (Copper sulphate and lime) should used for controlling the
development of diseases
• Acidic clays, milk and Baking soda are also used due to their fungicidal effect
Pests and diseases in agriculture act as a major barrier in the crop production in a developing
country like India. With such a huge population it becomes necessary for the people in the
agriculture sector to implement new ways to reduce pests and diseases in the crops, so that the
farmers can have a fruitful yield and minimize the losses making them economically sound.
4.2
Organic Methods of Pest and Disease Management
Vegetable pests: Type-1 (Leaf eating caterpillars and borers)
Shoot borer, Fruit borer, Stem borer, Hairy caterpillar (on drum stick) and army worm of
vegetable crops.
Control measures
1. Andrographis paniculata (siriyanangai) decoction 3 to 5 % or Sida spinosa (Arivalmani Poondu) decoction 5
For preparation of these decoctions, one of the above mentioned plants is taken and cut into
small pieces excluding roots. One kg of this is mixed with four litres of water and placed in a
mud pot. This is boiled and reduced to one litre. On cooling, 500 ml of this extract is mixed
with 100 ml of soap solution and 9.4 litres of water and sprayed on the top.
2. Neem Kernel extracts 500 to 2000 ml per tank (10 litres capacity) 3-5 kgs of neem kernel
is required for an acre. Remove the outer seed coat and use only the kernel. If the seeds
are fresh, 3 kgs of kernel is sufficient. If the seeds are old 5 kgs are required. Pound the
kernel gently and tie it loosely with a cotton cloth. Soak this overnight in a vessel containing
10 litres of water. After this, it is filtered. On filtering, 6-7 litres of extract can be obtained.
500-1000 ml of this extract should be diluted with 9 ½ or 9 litres of water. Before spraying
khadi soap solution @ 10 ml/litre should be added to help the extract stick well to the leaf
surface. This concentration of the extract can be increased or decreased depending on the
intensity of pest attack.
3. Garlic, Chilli, Ginger extract 500 to 1000 ml per tank (10 litres capacity) This is a mixture
of three plant extracts. 18 gm of garlic is taken, the outer skin is removed and made into
4.2 Organic Methods of Pest and Disease Management
Figure 4.1: Andrographis paniculata
(siriyanangai)
53
Figure 4.2: Sida spinosa (Arivalmani
Poondu)
paste. A paste of 9 gm of green chilli and 9 gm of ginger is made. All the three pastes are
dissolved in 1 litre of water. This mixture is stirred well and filtered before spraying. 500 ml
of this extract is made with 100 ml of soap solution and 9.4 litres of water and sprayed on the
top.
4.2.1
Vegetable pests: Type-2 (Sucking borers)
Aphids, Green plant hoppers, mealy bugs and white fly
Control measures
1. Andrographis paniculata (siriyanangai) decoction 3 to 5 % or Sida spinosa (Arivalmani
Poondu) decoction 5 %
2. Neem Kernel extract 500 to 2000 ml per tank (10 litres capacity)
3. Garlic, Chilli, Ginger extract 500 to 1000 ml per tank (10 litres capacity)
(Preparation mentioned in vegetable pest type-1)
Vegetable pests: Type-3 (Beetles and bugs): Leaf beetle (pumpkin beetle), pod sucking bug,
Epilachina beetles of vegetables
Control measures
1. Cow dung extract: Take 1 kg and mix it with 10 litres of water. Filter the extract with a gunny
cloth. Add 5 litres of water to the filtrate and again filter it with the same cloth. The filtrate
will be a very clear solution. Spray the filtrate on the plants.
2. Andrographis paniculata (siriyanangai) decoction 3 to 5 % or Sida spinosa (Arivalmani
Poondu) decoction 5
3. Neem Kernel extract 500 to 2000 ml per tank (10 litres capacity) (Preparation mentioned in
vegetable pest type-1)
Vegetable diseases: Tomato wilt, Fusarium wilt in Chilli, Cercospora leaf spot, Yellow mosaic
viral disease, alternaria leaf spot and fruit rot of all vegetable crops
4.2.1.1
Control methods
General methods
• 10 % cow’s urine is sprayed once in 10 days thrice.
• Half litre cow’s urine along with ½ litre sour butter milk is mixed with 9 litres of water.
This is sprayed once in 7 days twice.
• Cow’s urine and water is mixed in the ratio 1:2. The seeds or roots of seedlings are
soaked in this for half an hour before sowing or transplanting .
40
• kgs of neem cake per acre is applied as basal manure for vegetable crops to prevent
diseases.
• If there is a disease attack in the nursery, then add 10 % cow’s urine extract along with
the water that is used to irrigate the nursery.
54
Chapter 4. Pest & Disease Management and Harvesting
Figure 4.3: Neem Seeds and kernels
Fumigation combined with other organic methods 10 % cow’s urine extract should be sprayed
for crops affected by diseases. On the same day or the next day, fumigation should be done
in the evening. Embelica ribes (Vaividanga) is powdered well (200 grammes/acre). It is
then put in a wide mouthed pot with burning charcoal and carried in the field in a direction
opposite to the wind. On the 7th day after fumigation, 300 ml of Acorus calamus (Vasambu)
extract along with one litre of cow’s urine is mixed with 8.7 litres of water (measurement for
one tank) and sprayed on the crop. Vasambu powder in 2 litres of water and then filtering the
same. This method prevents wilting in chilli.
4.2.1.2
Non chemical other pest control methods
Light trap Light traps can be used to monitor and trap the adults thereby reducing the population.
Some common light traps that could be used are hurricane lamp, trap with electrical bulb
etc., The adult moths have an inherent capacity to get attracted to the light. It should be set
up in the field after 5.30 p.m. A large plate or vessel fitted with kerosene mixed water is kept
near the light trap. The attracted moths falls in this water and die.
Yellow sticky trap Castor oil smeared yellow colour empty tins or plates are kept in the field.
White flies get trapped on these sticky traps. These are wiped out every day and castor oil is
applied again.
Bird perches Install ‘T’ shaped bird perches which are long dried twigs @15-20 per acre. These
attract birds for resting and the resting birds devour the larvae in the field.
Hand picking method This method of pest is useful if the crop is in a small area. Pour a small
amount of kerosene in a polythene bag and pick up the larvae during evening hours and put
it in the bag. The pests can be controlled this way without the use of any chemicals. This
should be done when the pest numbers are low.
Hand picking of larva: Wild grasses and weeds should be removed from the field bunds and
field, since, these are the favourite egg laying spots of the pests.
Neem as pest repellent Take neem leaves or Neem cake or Neem kernels and pound it well and
place it in a pot. Add twice the volume of water and tie the mouth of the pot with a cloth.
Leave it as such for three days. Then, place the pots on all the 4 corners of a field. In the
evening, open the mouth of the pots. The foul smell emanating from the neem products
prevents entry of pests into the field.
4.3 Weed Management
4.3
55
Weed Management
Farmers have struggled with the presence of weeds in their fields since the beginning of agriculture.
Weeds can be considered a significant problem because they tend to decrease crop yields by
increasing competition for water, sunlight and nutrients while serving as host plants for pests and
diseases. Since the invention of herbicides, farmers have used these chemicals to eradicate weeds
from their fields. Using herbicides not only increased crop yields but also reduced the labor required
to remove weeds. Today, some farmers have a renewed interest in organic methods of managing
weeds since the widespread use of agro-chemicals has resulted in purported environment and health
problems. It has also been found that in some cases herbicides use can cause some weed species to
dominate fields because the weeds develop resistance to herbicides. In addition, some herbicides
are capable of destroying weeds that are harmless to crops, resulting in a potential decrease in
biodiversity on farmers. It is important to understand that under an organic system of seed control,
weeds will never be eliminated but only managed.
4.3.1
Critical period of weed control
This period has been defined as an interval in the life cycle of the crop when a must be kept weed –
free to prevent yield loss. If weeds have been controlled throughout the critical period, the weeds
that emerge later will not affect yield and can be controlled prior to harvest with a harvest and
to burn down the weeds and desiccate the crop. Horticulture crops are very sensitive to weed
competition, and need to kept weed-free, from planting, emergence or budbreak, until the end of
their critical weed –free period. If the crop is kept weed-free for the critical period, generally no
yield reduction would result. Again, weeds emerging after the critical weed-free period will not
affect yield, but control efforts after this time may make harvest more efficient, or reduce weed
problems in subsequent years in perennial crops.
4.3.2
4.3.2.1
Cultural Method
Crop rotation
Crop rotation involves alternating different crops in a systematic sequence on the same land. It
is an important strategy for developing a sound long term weed control program. Weeds tend to
thrive with crops of similar growth requirements as their own and cultural practices designed to
contribute to the crop may also benefit the growth and development of weeds. Monoculture, that is
growing the same crop in the same field yea after year, results in a build-up of weed species that are
adapted to the growing conditions of the crop. When diverse crops are used in a rotation, weed
germination and growth cycles are disrupted by variations in cultural practices associated with each
crop (tillage, planting dates, crop competition, etc).
Within a rotation, crop choice will determine both the current and the potential future weed
problems that a grower will face. Traditionally, potato (Solanum tuberosum L.) was included in the
rotation to reduce weed problems before a less competitive crop was grown. For an organic grower,
crop choice is complicated further by the need to consider soil fertility levels within the cropping
sequence and to include fertility building periods in the rotation. Variations in crop and weed
responses to soil nutrient levels can also play an important part in weed management. The inclusion
of a fallow period in the rotation in known to reduce perennial weeds. It is best to alternate legumes
with grasses, spring planted crops with fall planted crops, row crops with close planted crops and
heavy feeders with light feeders.
4.3.2.2
Cover crops
Rapid development and dense ground covering by the crop will suppress weeds. The inclusion
of cover crops such as rye, red, clover, buckwheat and oilseed radish or over wintering crops like
winter wheat or forages in the cropping system can suppress weed growth. Highly competitive
Chapter 4. Pest & Disease Management and Harvesting
56
crops may be grown as short duration ’smother’ crops within the rotation. Additionally, cover crop
residues on the soil surface will suppress weeds by shading and cooling the soil. When choosing a
cover crop, consideration should always be given to how the cover crop will affect the succeeding
crop. In addition, decomposing cover crop residues may release allelo chemicals that inhibit the
germination and development of weed seeds.
4.3.2.3
Intercropping
Intercropping involves growing a smother crop between rows of the main crop. Intercrops are
able to suppress weeds. However, the use of intercropping as a strategy for seed control should be
approached carefully. The intercrops can greatly reduce the yields of the main crop if competition
for water or nutrients occurs.
4.3.2.4
Field Scouting
It involves the systematic collection of weed and crop data from the field (weed distribution, growth
stage, population, crop stage etc). The information is used, in the short term, to make immediate
weed management decisions to reduce or avoid economic crop loss. In the long term, field scouting
is important in evaluating the success or failure of weed management programs and for making
sound decisions in the future.
4.3.2.5
Mulching
Mulching or covering the soil surface can prevent weed seed germination by blocking light
transmission preventing seed germination. Allelopathic chemicals in the mulch also can physically
suppress seedling emergence. There are many forms of mulches available. Listed are three common
ones.
1. Living mulch
Living mulch is usually a pant species that grows densely and low to the ground such as clover.
Living mulches can be planted before or after a crop is established. It is important to kill ad till
in, or manage living mulch so that it does not compete with the actual crop. A living mulch of
Portulaca oleracea from broadcast before transplanting broccoli suppressed weeds without affecting
crop yield. Often, the primary purpose of living mulch is to improve soil structure, aid fertility or
reduce pest problems and weed suppression may be merely an added benefit. 2. Organic mulches
Figure 4.4: Living Mulch Plants
Such materials as straw, bark, and composted material can provide effective weed control.
4.3 Weed Management
57
Producing the material on the farm is recommended since the cost of purchased mulches can
be prohibitive, depending on the amount needed to suppress weed emergence. An effective but
labor-intensive system uses newspaper and straw. Two layers of newspaper are placed on the
ground, followed by a layer of hay. it is important to make sure the hay does not contain any weeds
seeds. Organic mulches have the advantage of being biodegradable. Cut rye grass mulch spread
between planted rows of tomatoes and peppers was more economic than cultivation.
Figure 4.5: Polythene Mulch
Fresh bark of conifers and oak as well as rapeseed straw gave good control of weeds when they
were laid as mulches under the trees in apples orchards. Materials such as black polyethylene have
been used for weed control in a range of crops in organic production systems. Plastic mulches have
been developed that filter out photosynthetically active radiation, but let through infrared light to
warm the soil. These infrared transmitting mulches have been shown to be effective at controlling
weeds.
4.3.2.6
Planting patterns
Crop population, spatial arrangement, and the choice of cultivar (variety) can affect weed growth.
Fr example, studies have shown that narrow row widths and a higher seeding density will reduce the
biomass of later-emerging weeds by reducing the amount of light available for weeds located below
the crop canopy. Similarly, fast growing cultivars can have a competitive edge over the weeds.
4.3.2.7
Variety selection
Careful selection of crop varieties is essential to limit weeds and pathogen problems and to satisfy
market needs. Any crop variety that is able to quickly shade the soil between the rows and is able
to grow more rapidly than the weeds will have an advantage.
4.3.2.8
Tillage system
Tillage systems alter the soil seed bank dynamics and depth of burial of weed seeds. Studies have
found that almost 75% of the seedbank was concentrated in the upper 5 cm of soil in no-till fields.
In the moldboard plough system however, the seedbank is more uniformly distributed over depth.
Other conservation tillage systems are intermediate to these two systems.
Weed seedling emergence is often more uniform shallow buried weed seeds and may result
in better weed control. Weed seeds closer to the soil are more likely to be eaten or damaged by
insects, animals, other predators and disease causing organisms.
58
4.3.2.9
Chapter 4. Pest & Disease Management and Harvesting
Sanitation
It is possible to prevent many new weeds from being introduced onto the farm and to prevent
existing weeds from producing large quantities of seed. The use of clean seed, mowing weeds
around the edges of fields or after harvest to prevent weeds from going to seed, and thoroughly
composting manure before application can greatly reduce the introduction of weed seeds and
difficult weed species. It is even possible to selectively hand-eradicate isolated outbreaks of new
weeds, effectively avoiding future infestations. Planting clean, high-quality seed is essential to crop
success. Other sanitation factors to consider would include thorough cleaning of any machinery
which might have been used in weedy fields, and the establishment of hedgerows to limit windblown
seeds.
4.3.2.10
Nitrogen fertility
Nitrogen fertilizer can affect the competition between crops and weeds and in the subsequent crops.
For example, nitrate is known to promote seed germination and seed production in some weed
species. Nitrogen fertilization may result in increased weed growth instead of increased crop yield.
Selective placement of nitrogen in a band can favour the crop over the weed. Use of legume residues
are opposed to chemical nitrogen fertilizer to supplement nitrogen needs of the crop can enhance
weed suppression. Legume resules release nitrogen slowly with less stimulation of unwanted weed
growth.
4.3.2.11
Feed the crop, not the weeds
Avoiding pre-plant broadcasting of soluble nutrients that may be more readily utilized by fastgrowing weeds than slow-growing crops, and may even stimulate weed germination.
Applying fertilizer near the rows where it is more likely to be captured by the crop. Expensive
bagged organic fertilizer, may be applied low rates at planting or sidedress, relying on mid-season
release of nutrients from compost and / or green manures for primary fertility.
4.3.3
Water management
Effective water management is key to controlling weeds in a vegetable operation. There are a
number of ways that careful irrigation management can help to reduce weed pressure on the crops:
4.3.3.1
Pre-germination of weeds
In pre-germination irrigation or rainfall germinates weed seeds just before the cash crop is planted.
The newly germinated weeds can be killed by light cultivation or flaming. Pre-germination should
occur as close a possible to the date of planting to ensure that changes in weather conditions do not
have an opportunity to change the spectrum of weeds (cool vs. warm season) in the field.
4.3.3.2
Planting to moisture
Another technique similar to pre-germination is planting to moisture. After weeds are killed by
cultivation, the top 2 to 3 inches of soil are allowed to dry and form a dust mulch. At planting, the
dust mulch is pushed away and large-seeded vegetables such as corn or beans can be planted into
the zone of soil moisture. These seeds can germinate, grow, and provide partial shading of the soil
surface without supplemental irrigations that would otherwise provide for an early flush of weeds.
4.3.3.3
Buried drip irrigation
Drip tape buried below the surface of the planting bed can provide moisture to the crop and minimize
the amount of moisture that is available to weeds closer to the surface. If properly managed, this
technique can provide significant weed control during dry period.
4.4 Mechanical Weed Control
4.4
59
Mechanical Weed Control
Mechanical removal of weeds is both time consuming and labor-intensive but is the most effective
method for managing weeds. The choice of implementation, timing, and frequency will depend on
the structure and form of the crop and the type and number of weeds. Cultivation involves killing
emerging weeds or burying freshly shed weed seeds below the depth from which they germinate. It
is important to remember that any ecological approach to weed management begins and ends in the
soil seed bank. The sol seedbank is the reserve of weed seeds present in the soil. Observing the
composition of the seedbank can help a farmer make practical weed management decisions. Burial
to 1 cm depth and cutting at the soil surface are the most effective ways to control weed seedlings
mechanically.
Mechanical weeders include cultivating tools such as hoes, harrows, tines and brush weeders,
cutting tools like mowers and stimmers, and dual-purpose implements like thistle-bars. The choice
of implement and the timing and frequency of its use depends on the morphology of the crop and
the weeds. Implements such as fixed harrows are more suitable for arable crops, whereas inter-row
brush weeders are considered to be more effective for horticultural use. The brush weeder is mainly
used for vegetables such as carrots, beetroot, onions, garlic, cerely and leeks. The optimum timing
for mechanical weed control is influenced by the competitive ability of the crop and the growth
stage of the weeds.
Hand hoes, push hoes and hand-weeding are still used when rouging of an individual plant or
patch of weed is the most effective way of preventing the weed from spreading. Hand-weeding
may also be used after mechanical inter-row weeding to deal with weeds left in the crop row.
Blind, ’over-the top’ cultivation controls very small weeds, just germinated or emerged, before
and sometimes after planting. The entire surface of the fields is worked very shallow using flex-tine
cultivators (e.g. Lely weeder or rotary hoes, Inter-row cultivations with a rotary hoe in pinto beans
(Phaseolus vulgaris L.) gave adequate weed control without reducing plant stand or injuring the
crop.
The hoe-ridger is specifically designed to achieve intra-row control in sugar beet, Thistle-bars
are simple blades used to undercut perennial weeds with minimal soil disturbance. The brush
weeder, or brush hoe, is used primarily for inter-row weeding of vegetable crop.
Shallow between-row cultivators such as basket-weeders, beet-hoes, or small sharp sweeps are
used to cut off and uprrt small weeds after the crop is up. These can get very close to the crop when
it’s small, without moving much soil into the row, and may be the only tools used on delicate crops
like leafy greens, As vigorous crops grown, soil can be thrown into the row to bury in – row weeds
using rolling cultivates (e.g. Lilliston), spyder wheels (e.g. Bezzerides), large sweeps or hilling
disks. Some of these tools can be angled to pull soil away from the row when plants are small and
later turned around to throw soil back on the row during subsequent cultivators.
4.5
4.5.1
Thermal Weed Control
Flamers
Flamers are useful for weed control. Thermal weed control involves the use of flaming equipment
to crate direct contact between the flame and the plant. This technique works by rupturing plant
cells when the sap rapidly expands in the cells. Sometimes thermal control involves the outright
burning down of the weeds. Flaming can be used either before crop emergence to give he crop a
competitive advantage or after the crop has emerged. However, flaming at this point in the crop
production cycle may damage the crop. Although the initial equipment cost may be high, flaming
for weed control may prove cheaper than hand weeding.
Propane – fuelled models of flamers are the most commonly used. Flaming dose not burn
weeds to ashes; rather the flame rapidly raises the temperature of the weeds to more then 130
°F. The sudden increase in temperature causes the plants cell sap to expand, rupturing the cells
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Chapter 4. Pest & Disease Management and Harvesting
walls. For greatest flaming efficiency, weeds must have fewer than two true leaves. Grasses are
difficult to impossible to kill by flaming because the growing point is protected underground. After
flaming, weeds that have been killed rapidly change from a glossy appearance to a duller appearance.
Flame weeders can be used when the soil is too moist for mechanical weeding and there is no soil
disturbance to stimulate further weed emergence.
Flaming can be used prior to crop emergence in slow-germinating vegetables such as peppers,
carrots, onion, and parsley. Onions have some tolerance to flaming and flame weeding has eben
successful in both pre and post-crop emergence conditions and after transplanting. Transplanted
cabbage has some tolerance to heat, allowing band flaming to be used along the crop row. Damage
can occur when the treatment is applied too early, but the crop usually recovers. In a young pear
orchard, where treatments were started on a clean soil after cultivation, flaming kept weed growth
in check. In an established apple orchard, there was insufficient control of perennial weeds. Best
results are obtained under windless conditions, as winds can prevent the heat from reaching the
target weeds. The efficiency of flaming is greatly reduced if moisture from dew or rain is present
on the plants. Early morning and early evening are the best times to observe the flame patterns and
adjust the equipment.
4.5.2
Soil solarization
During summer and fall, organic farmers sterilize their soil through solarization. In this process,
a clear plastic film is placed over an area after it has been tilled and tightly sealed at the edges.
Solarization works when the heat crated under the plastic film becomes intense enough to kill weed
seeds.
4.5.3
Infrared weeders
Infrared weeders are a further development of flame weeding in which the burners heat ceramic
or metal surfaces to generate the infrared radiation directed at the target weeds. Some weeders
use a combination of infrared and direct flaming to kill the weeds. In general, flame weeders are
considered to be more effective because they provide higher temperatures, but burner height and
plant stage are important too. Infrared weeders cover a more closely defined area than those of the
standards flame weeder, but may need time to heat up. ’
4.5.4
Freezing
Freezing would be advantageous only where there is an obvious fire risk from flaming. Liquid
nitrogen and solid carbondioxide (dry ice) can be used for freezing weeds.
Various test systems using electrocution, microwaves and irradiation have also been evaluated
for weed control purposes, but high energy inputs, slow work rates and the safety implications for
operators have hampered developments. Lasers have been shown to inhibit the growth the Eichornia
crasispes (water hyacinth) but did not kill the weed completely. Weed control using ultraviolet light
has been patented but remains at an experimental stage.
4.6
Biological Weed Control
Biological control would appear to be the natural solution for weed control in organic agriculture.
4.6.1
Allelopathy
Allelopathy is the direct or indirect chemical effect of one plant on the germination, growth or
development of neighboring plants. I is now commonly regarded as component of biological
control. Species of both crops and weeds exhibit this ability. Allelopathic crops include barley,
rye, annual ryegrass, buckwheat, oats, sorghum, sudan sorghum hybrids, alfalfa, wheat, red clover,
and sunflower. Vegetables, such as horseradish, carrot and radish, release particularly powerful
4.7 Harvesting
61
allelopathic chemicals from their roots. Suggestions have been made that allelochemicals and other
natural products or their derivatives could form the basis of bioherbicides. However, it is unclear
whether the application of natural weed killing chemicals would be acceptable to the organic
standard authorities.
The alleopathic effect can be used to an advantage when oats are sown with a new planting
of alfalfa. Alleopathy from both the alfalfa and the oats will prevent the planting from being
choked with weeds in the first year. Buckwheat is also well known for its particularly strong
weed suppressive ability. Planting buckwheat on weed problem, fields can be an effective cleanup
technique. Some farmers allow the buckwheat to grow for only about six week before plowing
under. This not only suppress and physically destroys, weeds; it also release phosphorus and
conditions the soil.
4.6.2
Beneficial organisms
Little research has been conducted on using predatory parasitic microorgniams or insects to manage
weed populations. However, this may prove to be a useful management tool in the future. Natural
enemies that have so far been successful include a weevil for the aquatic weed salvinia, a rust for
skeleton weed and probably the most famous, a caterpillar (Cactoblastis sp.) to control prickly pear.
There is also considerable research effort aimed at genetically engineering fungi (myco-herbicides)
and bacteria so that they are more effective at controlling specific weeds. Myco-herbicides are a
preparation containing pathogenic spores applied as a spray with standard herbicide application
equipment.
Weeds are subject to disease and insect attacks just as crop are. Most biological control of
weeds occurs in range or non crop areas. As a result, biological control has little relevance for
vegetable growers. Geese have been used for weed control in trees, vine, and certain row crops.
Most types of geese will graze weeds, but Chinese weeder geese are considered the best for row
crops. Chinest weeder geese are smaller than other types and tend to walk around delicate crop
plants rather than over them. Geese prefer grass species and rarely eat crops. If confined, geese
will even dig up and eat Johnson grass and Bermuda grass rhizomes. Care must be taken to avoid
placing geese near any grass crops such as corn, sorghum, or small grains, as this is their preferred
food. Fruiting vegetables, such as tomatoes when they begin to color, might also be vulnerable, so
geese would have to be removed from tomato fields at certain times. Geese require drinking water,
shade during hot weather, and protection from dogs and other predators.
4.6.3
Use of biocontrol agents for weed control
4.6.4
Use of fish for weed control
Name of the weeds
4.7
Harvesting
Harvesting usually consists of a series of operations – digging, lifting, winnowing, stocking and
threshing. Depending on the system used, some of these can be combined or eliminated. During
harvest, pod loss is more with the Virginia type than the Spanish types. The loss may be due to
various reasons such as harvesting after the optimum maturity period, early harvesting, method of
harvesting, excess soil moisture, soil moisture deficit, etc. Soil moisture level is very critical during
harvesting. At the time of digging, soil moisture is most important both to reduce pod losses due to
poor peg strength and in situ sprouting of seed. When the crop reaches its physiological maturity,
irrigation should be stopped. At the same time, it should be maintained at the optimum level during
the harvest.
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Chapter 4. Pest & Disease Management and Harvesting
Figure 4.6: Competitive weeds
4.7.1
Timing of harvest
Groundnut shows indeterminate growth. The flowering occurs over 2–3 months according to
the type of variety. Hence, pods of different sizes can be found during harvesting. The time for
harvesting can be determined by pulling out and examining the plant at random. At maturity,
yellowing of the top leaves and drying and shedding of older leaves are observed. Spanish and
Valencia types of groundnut usually mature 110 to 130 days after sowing, while the Virginia
types takes 130 to 150 days. Once the pods are mature, they should be harvested without delay.
Harvesting at the right time helps to obtain good yields of pods and oil. If they are not harvested at
4.7 Harvesting
63
Figure 4.7: Types of Harvesting
optimum maturity, they are prone to Aspergillus attack; late harvesting also results in sprouting of
pods in the field. The nut takes two months to attain full development. A fully mature pod will be
difficult to split easily with finger pressure. This stage is achieved when the vine begins to turn
yellow and the leaves start shedding. Delay in harvesting may result in substantial loss in yields.
4.7.2
Method of harvest
The bunchy varieties are harvested by hand and the spreading varieties by digging, ploughing or
by working with a blade-harrow. Groundnut should be harvested in bright sunshine so that the
pods and vines can be dried thoroughly. Prevalence of high humidity during harvesting leads to
development of mould in pods.
4.7.2.1
Special techniques
There are chances of the groundnut pods germinating before harvesting. This can be avoided by
providing a foliar application of Prosopis pod extract or 20% neem seed kernel extract. To prepare
the extract, 100 kg of powdered Prosopis pods or neem seed kernels are soaked in 200 litres of
water and filtered through a muslin cloth. The extract is diluted to 500 litres for spraying in one
hectare of groundnut crop. The use of this extract is effective in inducing dormancy up to 11 days.
4.7.2.2
Yield
Yield varies in different states. It is determined by factors such as rainfall, soil type, management
and crop protection practices. The yield is usually higher in the Virginia-runner type than in the
Spanish-Valencia type. The yield of an irrigated crop in the summer is more than double that of a
kharif crop. Under rain-fed conditions, the average yield of semi-spreading and spreading varieties
is 1.2–1.4 tonnes of pods per hectare and that of the bunch type is between 0.8–1 tonne/ hectare.
Figure 4.8: Manual Harvesting
Figure 4.9: Mechanised Harvesting
64
4.8
4.8.1
Chapter 4. Pest & Disease Management and Harvesting
POST HARVEST MANAGEMENT
Stripping
Stripping is the process of removing groundnut pods from the haulm after lifting, and usually,
drying. After harvest, the pods should be immediately stripped off from the plants or after a few
days of drying in the sun. Stripping is normally done by hand and is a tedious and time-consuming
operation. The pods are usually removed by picking or flailing.
Figure 4.10: Post Harvest Management
4.8.2
Drying
The pods should be dried in the sun for at least 7–10 days to obtain a safe moisture level. If by
chance the pods are stored damp, there are chances of mould development and this may result in
aflatoxin contamination.
4.8.3
Packaging and storage
The moisture content of the pods should be less than 10% during storage. Spread husk or sand or
wooden boards on the floor of the storage rooms to inhibit moisture contamination. Groundnut
pods can be stored for about 6–7 months by using camphor. This is a common farmer’s practice:
the fully dried groundnut pods are filled in polythene lined gunny bags to a height of 30 cm after
which a few pieces (8–10) of camphor are placed in them before filling them further. After the
entire bag is filled up, its mouth is tied tightly.
The bags are kept in a moisture-free area. This work has to be completed before the onset of
the monsoon. For every 400 kg of groundnut, mix 2 kg of neem leaves. This will act as a repellent
for storage pests.
4.9 Storage
Figure 4.11: Packaging of Fruits
4.8.4
65
Figure 4.12: Packaging of Vegetables
Shelling
Shelling is usually carried out when the moisture content of the pod is less than 10%. Shelling is
done by hand or with the use of a pedal-operated groundnut decorticator or hand-operated sheller.
4.9
Storage
followed in post harvest handling, before packaging storage, transport or marketing to minimize
loss and maintain quality.
Additional operation: Along with grading, certain additional operation which include washing,
pre cooling, degreening, curing, waxing, fungicidal and other chemical treatment are also essential
preparatory steps to packaging , storage transportation and subsequent marketing, washing, improves appearance, remove dirt, soil, scale insect, sooty mould, fungicide and insecticide residues.
Detergent are added to water for effectiveness washing. The excess of surface water is dried by
blowing heated air.
Pre-cooling: Pre-cooling is done to remove field heat as high temperature is detrimental to the
keeping quality of fruits and vegetables. General aims are to slow down the respiration minimize
the susceptibility to micro organism and reduce water loss. Several methods used are
• air-cooling,
• hydro cooling- fungicides can be added in cooling water.
• vacuums cooling- most rapid methods of pre cooling, especially, for leafy vegetables curingcertain vegetables like onion have to be cured after harvest before storage and transport
marketing.
Degreening: In certain cases development of ripe colour by degrading the green colours is induced
usually by the treatment with ethylene under controlled temperature and humidity and O2 and CO2
concentration e.g. Banana, Mango, Citrus, Tomato.
Waxing:
1. Waxing is done to reduce the evaporation loss of water from the fruits and vegetables thereby
increasing the storage life
2. It gives a fresh glossy appearance which improves the market value.
3. Recommended fungicides can be added to the wax to reduce the spoilage buy fungus.
The wax replaces the natural protecting waxy layer which is removed by handling, washing, etc.
CFTRI Mysore, has developed a wax emulsion (Waxol-123) for waxing of fruits and vegetables.
4.9.1
Packaging
Packaging is done for more efficient handling and marketing , greater appeal, more potential
life. Packaging requirement vary with different fruits and vegetables. Packaging cannot improve
quality. Hence only best possible produce should be packed. Inclusion of decayed or damaged
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Chapter 4. Pest & Disease Management and Harvesting
produced in bulk or consumer packages may become a source of infection and reduce the sale at
the market. Packaging is not a substitute for refrigeration; packaging combined with refrigeration
is the best methods. A good package is aim to protection of product from physical. Physiological
and pathological deterioration causes throughout storage, transport and market.
Figure 4.13: Agriculture Produce Package
Benefits of packaging:- serves as an efficient handling units, serves as a good storage unit, protect
quality and reduce waste, protect from mechanical damage and moisture loss, provide
beneficial modified atmosphere, prevent pilferage, provides service and sales motivation.
Material for packaging:- wooden boxes, bamboo basket are the conventional packs. Fibre board
cartoons, corrugated card boards, and several flexible plastic packaging.
Materials used for packing material are
1. polyethylene (low density)-most widely used for consumer packaging ,strong considerably moisture proof , resistant to several chemicals and cheap
2. polyprophlene
3. polyvinyl chloride film
4. cellophane
5. polifilm.
The emphasis is being made now to use those materials which contains less or no wood for
packaging as our forest resources being exhausted fastly and is at a precarious condition.
Consumer packaging with plastic:- the original function of packaging was to contain carry and
dispence products. However the use of plastic as packaging materials has allowed so much
variation and versatility as to protect ,presence, process, store, measure, communicate, and
display of products. Fruits and vegetables are packaged in smaller quantities in polyethylene
pouches as consumer packages. In these films proper ventilation is needed to prevent moisture
4.10 Handling and Storage of Horticultural Crops
67
accumulation. Leading to rotting of the content and to relegate O2 and CO2 concentration
inside pack. High CO2 concentration may cause deterioration in quality of the content.
Congenial modified atmosphere inside the pack would increases the storage life of the
contents.
Pre Packaging:- Pre packaging increases the shelf life by creating modified atmosphere with
an increase in concentration of CO2 in package. L.D.P.E. films have high O2 and CO2
transmission rates are more durable.
The pouch used reducing bruising facilitates inspection, reduces moisture losses and prevent
dehydration. In pre packaging leaves stalk stem are washed cleaned and weight quantities are put
in pouches.
Ethylene absorbents hydrate lime may insert in packages to retard ripening process.
A wide range of packages like gunny bags, bamboo ,woven ,grass stem basket, wooden cares,
earthen pots, corrugated fibre board cartoons and rigid plastic carats are used.
Wheat and paddy straws, banana leaves, dry grass are used as cushioning material.
4.10
Handling and Storage of Horticultural Crops
4.10.1
Storage
Storage of fruits and vegetables prolongs their usefulness, it is also check market glut, provide wide
selection of fruits and vegetables throughout the year, helps in orderly, marketing, increases profits
to the producers and preserve the quality of the living products.
The principal aim of storage is to control rate of transpiration, respiration and disease infection
and to preserve the commodity in its most usable form for consumers without proper storage, the
following undesirable things may occur
Sprouting:- e.g. onion, ginger, garlic, potatoes etc.
Rooting:- e.g. sweet potato, onion etc.
Seed germination:- e.g. pod bearing vegetables, tomato, papaya etc.
Degreening:- e.g. potatoes of exposed to light, green portion contain solanin which is toxic.
Toughening:- e.g. Green beans, bhindi etc.
4.10.1.1
Factors affecting storage
1.
2.
3.
4.
5.
4.10.1.2
Pre-harvested factors: climatic, cultural, and pathogenic
Harvesting and handling practices: mechanical injuries
Pre-cooling: an important factor prior to storage reduces P.L.W. and improves storage life.
Cleanliness
Variety and stage of maturity at harvest - prematurely harvested mango, bananas, tomatoes
will not ripe satisfactorily.
Storage life
It may be prolonged by
• proper control of post harvested diseases
• chemical treatments
• irradiation
• refrigeration
• controlled atmosphere storage.
a. Proper control of post harvest diseases: Knowledge of the time and made of infection is essential for the development of an effective programme for diseases control. Fruits attached to
the plant may be infected by direct penetration of a fungus through enticle by wounds or by
natural openings. Many most harvested diseases are through injuries after harvest such as cut
68
Chapter 4. Pest & Disease Management and Harvesting
Figure 4.14: Agriculture Produce Storage
steams and mechanical damage to the surface in the course of handling and transporting.
Cut-stem infection: e.g. crown root of banana hands, black-root of pineapple and stem end
root of papaya and mango.
Post harvested diseases initiated in wound create during or after harvest may be controlled
by fungicides treatment. If application can be made before pathogen has penetrated deep into
the fruits.
Low temperature reduces the severity of post harvest diseases by retarding ripening and also
by retarding the growth of micro-organism
Humidity more than 90% favour the development of post harvest diseases. Plastic films of
low permeability and without ventilation increases post harvest diseases.
Control of post harvest diseases – the basic principles are
1. prevention
2. cure
3. delaying the appearance of symptoms and
4. retarding diseases spread more than one approach is usually required for satisfactory
diseases control.
b. Chemical treatments: Growth regulators like GA, MH, CCC, ALAR, and other chemicals like
acetylene gas ethylene gas are used to regulate ripening and storage life of fruit and vegetables.
Post harvest treatment with GA markedly retards ripening and tomatoes guava, bananas and
mangoes.
4.10 Handling and Storage of Horticultural Crops
69
Malik hydrazide (MH) a growth retardant inhibits spouting of onion, potato. Ethylene,
acetylene are used to hasten ripening in fruits.
c. Irradiation: Low radiant dosage is applied to fresh fruits and vegetables to prolong their
storage life. Irradiation can delay the ripening destruction of spoilage micro-organism and
disinfection. It has been used successfully in retarding the sprouting of potatoes, sweet
potatoes, onion. Irradiation is successful in control of fruit fly on citrus, mango seed, weevil
control, papaya fruit fly control. For some fruit like mango, banana, papaya and additional
advantage in the use of irradiation for disinfestations purpose is retardation of ripening. in
several vegetables irradiation is not useful as it causes discoloration excessive softening, off
flavour, increase decay etc.
Irradiation method is not cleared as safe to use for prolongation of shelf life of fruits and
vegetables in India though its use in certain commodities like onion and potatoes is cleared
in several other countries.
d. Refrigeration: To date refrigeration is the only known economical methods for long term
storage of fruits and vegetables, all the other methods of regulating ripening and deterioration
are at best supplemental to refrigeration. Other methods are not worked satisfactory without
refrigeration. Refrigeration requirements vary with different kinds of fruits and vegetables
and their maturity stages which are standardized.
Optimum temperature for the even ripening and development of good flavor, and attractive
colour of most fruits generally fall within a range of 15-35°C. mangoes ripened at 20°C
contains 20% as much sugar as these ripened at 4°C at storage temperature of about 24°C is
optimum for the storage of most fruits except grapes, litchi, pomegranate, and apple which
require a low temperature range 0 to 9°C. Leafy vegetables require 90% to 96% R.H. They
should not be stored together with ripening fruits as ethylene is injurious to them.
Fruit and vegetables bean cucumbers, bhendi, sweet peeper, squash and tomatoes are sensitive
to chilling at very low temperature. They are to be stored as 4 to 10°C . Higher temperature
cause toughening, yellowing and decay while low temperature cause pitting.
Chilling injury: A major problems in post harvest handling at low temperature which otherwise would prolong their storage life .chilling injury is a disorder induced by low, but non
freezing temperature is susceptible fruits and vegetables.
(a) pitting- limes, mangoes, avocado.
(b) water-soaking – tomato
(c) smoky-appearance- banana
(d) surface discoloration- mango etc.
(e) Controlled atmosphere storage: Controlled atmosphere (CA) implies to addition or removal
of gases, resulting in an atmospheric composition substantially different from normal air.
CA storage is a system for holding produce in respect to the proportion of nitrogen (N2),
oxygen(O2), or carbon dioxide (CO2). Other gasses such as CO or ethylene are also added to
the storage atmosphere. CA storage process could be the most important innovation in fruit
and vegetables storage since the introduction of mechanism of refrigeration. This method, if
combined with refrigeration markedly retards respiration activity and may delay softening
yellowing, quality change etc.
V
Module V
5
Case Studies . . . . . . . . . . . . . . . . . . . . . . . . 73
5.1
5.2
Case studies of successful organic farming . . . 73
Visit to a nearby organic farm/horticulture institute
and report writing . . . . . . . . . . . . . . . . . . . . . . 73
Bibliography . . . . . . . . . . . . . . . . . . . . . . . . 75
Articles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Books . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
5. Case Studies
5.1
Case studies of successful organic farming
5.2 Visit to a nearby organic farm/horticulture institute and report
writing
Bibliography
Articles
Books