Table of Contents
- Organic farming is a type of agriculture or farming which avoids the use of synthetic fertilizers, pesticides, growth regulators, and livestock feed additives.
- Organic farming systems rely on crop rotation, crop residues, animal manures, legumes, green manure, off-farm organic wastes and biofertilizers, mechanical cultivation, mineral bearing rocks to maintain soil productivity to supply plant nutrients and biological pest control, controlling weeds, insects and other pests.
- All kinds of agricultural products can be produced organically, including grains, meat, dairy, eggs, fibres such as cotton, jute, flowers etc.
- Organic farmers build healthy soils by nourishing the microbial inhabitants that release, transform, and transfer nutrients. Soil organic matter contributes to good soil structure and water-holding capacity.
- Organic farmers feed soil biota and build soil organic matter with cover crops, compost, and biologically based soil amendments.
- Organic farmers’ primary strategy in controlling pests and diseases is prevention through good plant nutrition and management.
- Organic farmers use cover crops and sophisticated crop rotations to change the field ecology, effectively disrupting habitat for weeds, insects, and disease organisms.
- Weeds are controlled through crop rotation, mechanical tillage, and hand-weeding, as well as through cover crops, mulches, flame weeding, and other management methods.
- Organic farmers rely on a diverse population of soil organisms, beneficial insects, and birds to keep pests in check.
- When pest populations get out of balance, growers implement a variety of strategies such as the use of insect predators, mating disruption, traps and barriers.
- Vermicomposting is an appropriate technique for efficient recycling of animal wastes, crop residues and agro-industrial wastes.
- The process of conversion of organic materials into manure is chiefly microbiological.
- Earthworms are important for producing vermicompost from organic wastes.
- Vermicompost can be prepared from all sorts of organic residues – animal waste, sericulture residues, dairy and poultry residues, bagasse from sugarcane factories, weeds (particularly Parthenium hysterophorus or Congress weed before flowering) etc.
National Programme for Organic Production (NPOP)
What it does?
Organic products are traded only through issuance of Transaction Certificates (TCs) wherein the product identity and traceability are maintained.
The testing is to be carried out in ISO 17025 accredited and preferably APEDA approved laboratories.
Q. With reference to organic farming in India, consider the following statements: (2018)
Which of the statements given above is/are correct?
Answer: b) 2 and 3 only
- In this approach, each crop and its pests are evaluated as parts of an ecological system.
- Then farmers develop a control programme that includes cultivation, biological and chemical methods applied in proper sequence and with the proper timing.
- The aim of IPM is not to eradicate the pest population completely but to keep the crop damage to economically tolerable level.
- Farmers monitor the field and when they find the pest level to be high enough, they first use biological methods and cultivation practices to control and then use small amounts of insecticides mostly insecticides derived from plants as a last resort.
- Natural predators, parasites and pathogens of the pests are used.
- Example: Pest on cucumber plant called red spider mite is controlled by using a predatory mite that feed on red spider mite.
- A variety of cultivation practices like crop rotation, polyculture and inter cropping etc. can be used to get rid of the pests.
- Some amounts of insecticides, mostly of plant origin (e.g. Pyrethrum and Rotenone neem product) are applied as a last resort.
- Pest and disease resistant crop plants can be produced by genetic engineering. Example is Bt cotton, insecticidal for bacterial gene (Bacilus thuringinesis) introduced into cotton plant making cotton plant resistant to pest.
- Farmer should have an expert knowledge about each pest.
- It acts more slowly than conventional pesticides.
- Methods developed for a crop in one area might not apply to areas with even slightest different growing conditions.
- Initial cost may be higher but in the long-term cost become very low.
- For a sustainable agriculture system, it is essential to use renewable inputs (fertilizer, pesticides, water etc.) which can benefit the plant and cause no or minimal damage to the environment.
- One of the energy efficient and pollution free method is to exploit the ability of certain microorganisms like bacteria, algae and fungi to fix atmospheric nitrogen, solubilize phosphorus, decompose organic material or oxidize sulphur in the soil.
- When they are applied in the soil, they enhance growth and yield of crops, improve soil fertility and reduce pollution. They are known as “bio fertilizers”.
- Thus bio-fertilizers are living or biologically active products or microbial inoculants of bacteria, algae and fungi (separately or in combination) which are able to enrich the soil with nitrogen, phosphorus, organic matter etc.
- Following are some of the important types of bio fertilizers which can be considered for agro based industries.
- Rhizobium is a symbiotic bacterium forming root nodules in legume plants.
- These nodules act as miniature nitrogen production factories in the fields.
- The nodule bacteria fix more nitrogen (N2) than needed by legume plant and the bacteria.
- The surplus fixed nitrogen is then secreted and fertilizes the soil.
- Rhizobium is more efficient than-free living nitrogen-fixing bacteria.
- Azotobacter are aerobic free living nitrogen fixers.
- They grow in the rhizosphere (around the roots) and fix atmospheric nitrogen non-symbiotically and make it available to the particular cereals.
- These bacteria produce growth promoting hormones which helps in enhancing growth and yield of the plant.
- These are aerobic free living nitrogen fixers which live in associative symbiosis.
- In this type of association bacteria live on the root surface of the host plant and do not form any nodule with roots of grasses.
- It increases crop yield and its inoculation benefits crop.
- They also benefit the host plants by supplying growth hormones and vitamins.
- These bacteria are commonly used for the preparation of commercial inoculants (vaccines, culture medium).
- Blue green algae (BGA or cyanobacteria) like Nostoc and Anabaena are free living photosynthetic organisms also capable of fixing atmospheric nitrogen.
- In the flooded rice fields blue green algae serves as a nitrogen biofertilizer.
Q. Consider the following organisms
Which of the above is/are used as biofertilizer/biofertilizers
- 1 and 2
- 2 only
- 2 and 3
- 3 only
Answer: b) 2 only
- Azolla is a water fern inside which grows the nitrogen fixing blue green algae Anabaena.
- It contains 2-3% nitrogen when wet and also produces organic matter in the soil.
- The Azolla-Anabaena combination type biofertilizer is used all over the world.
- The only constraint in Azolla is that it is an aquatic plant and water becomes limiting factor in growing it particularly in summer.
- Phosphorus is an important element required for plant growth.
- This element is also needed for nodulation by rhizobium.
- Some microorganisms are capable of solubilizing immobilized phosphorus making it available to plants for absorption.
- Mycorrhizal fungi acts as biofertilizer and are known to occur naturally on roots of forest trees and crop plants.
- Mycorrhizal fungi resist disease in plants. The plants also show drought and salinity resistance. Plants can tolerate adverse soil, pH, high temperature and heavy metal toxicity.
- In soils low in available nutrients there is an increased absorption of nutrients by plants infected with Mycorrhiza.
- The fungus has the ability to dissolve and absorb phosphorus that plant roots cannot readily absorb.
Q. Mycorrhizal biotechnology has been used in rehabilitating degraded sites because mycorrhiza enables the plants to
- resist drought and increase absorptive area
- tolerate extremes of pH
- Resist disease infestation
Select the correct answer using the codes given below:
- 1 only
- 2 and 3 only
- 1 and 3 only
- 1, 2 and 3
Answer: d) all
- Compost Tea is a liquid fertilizer for flowers, vegetables and houseplants.
- Compost tea is an aerobic (in the presence of oxygen) water solution that has extracted the microbe population from compost (dead and decaying matter) along with the nutrients.
- In simple terms, it is a concentrated liquid created by a process to increase the numbers of beneficial organisms as an organic approach to plant/soil care.
- Air is sent through the water to keep the water oxygenated, as this favours the beneficial bacteria and fungi over the pathogens.
- At the end of the brewing cycle, what you have is a concentrated liquid full of billions of microorganisms (bacteria, fungi, protozoa, nematodes) that can then be sprayed directly onto the leaf surface.
- The liquid fertilizer occupies the infection sites on the leaf surface and is held there by simple sugars that the plant puts out that work as a glue to keep the beneficial microorganisms thriving and protecting the plant.
- Bio char is found in soils around the world as a result of vegetation fires and historic soil management practices.
- Intensive study of bio char-rich dark earths in the Amazon (terra preta), has led to a wider appreciation of bio char’s unique properties as a soil enhancer.
- Bio char is charcoal that is used as soil amendment (minor improvement).
- It is created using a pyrolysis process (decomposition brought about by high temperatures), heating biomass in a low oxygen environment.
- Once the pyrolysis reaction has begun, it is self-sustaining, requiring no outside energy input.
- By-products of the process include syngas (H2 + CO), minor quantities of methane (CH4), organic acids and excess heat.
- Once it is produced, bio char is spread on agricultural fields and incorporated into the top layer of soil.
- The syngas and excess heat can be used directly or employed to produce a variety of biofuels.
Agricultural Benefits of Bio char
- It increases crop yields, sometimes substantially if the soil is in poor condition.
- It helps to prevent fertilizer runoff and leeching, allowing the use of less fertilizers.
- It retains moisture, helping plants through periods of drought more easily.
- Most importantly, it replenishes exhausted or marginal soils with organic carbon
- It fosters the growth of soil microbes essential for nutrient absorption, particularly mycorrhizal fungi.
- Bio char can increase soil fertility of acidic soils. (The most fertile soils are slightly acidic)
- Bio-char reduces the acidity of the soil, protects the plants from diseases, promotes growth of friendly microorganisms, and reduces the loss of micro nutrients apart from increasing water retain-ability.
Kollam, Kerala, is famous for fishing and fishery-related activities; as an agricultural sector, it does not evoke any enthusiasm. Why?
- With the prevailing soil and climatic conditions which favours leaching and draining of soil nutrients into the Arabian sea and Ashtamudi Lake, the soil has high acidity making it unfit for cultivation of any kind (friendly microorganisms don’t like acidic medium. They like slightly alkaline or basic medium).
- Bio char can make a difference to the agriculture of the region.
Other Environmental Benefits
- Most carbon in the soil is lost as greenhouse gas (carbon dioxide, CO2) into the atmosphere if natural ecosystems are converted to agricultural land.
- Soils contain 3.3 times more carbon than the atmosphere.
- This makes soils an important source of greenhouse gases but also a potential sink if right management is applied.
- The use of crop residues for bio-energy production reduces the carbon stocks in cropland.
- Further the dedication of cropland to bio-fuel production increases the area of cultivated land and thus carbon loss from soils and vegetation.
- Bio char remains stable for millennia, providing a simple means to sequester carbon emissions.
- If bio char is returned to agricultural land it can increase the soil’s carbon content permanently and would establish a carbon sink for atmospheric CO2.