Fundamentals of Organic Farming

EDC COURSE MATERIAL

(For UG final year students)

Course offered by

DEPARTMENT OF BIOTECHNOLOGY SCHOOL OF BIOLOGICAL SCIENCES CMS COLLEGE OF SCIENCE & COMMERCE COIMBATORE-641049

Contents

Unit No Topics Page no I Organic farming 1 I Land and water management 7 I Nutrient recycling 15 I Crop rotations 19 I Organic farming & Indian economy 21 II Methods of organic farming 27 II Relevance to pollution free environment 30 II Marketing and export 32 II Certification and labelling 34 II Accreditation 36 III Organic manure 38 III Green manure 40 III Compost-methods 41 IV Biofertilizers-types 46 IV Production of biofertilizers 48 IV Applications & Importance 52 V Biological pest control 54 V Neem insecticides 58 V Integrated pest management 60 V Bt Insecticide 62 V Control of weeds 66

UNIT I

Organic farming

Due to decades of indiscriminate use of chemical fertilizers the organic matter content of soils has come down. The use of chemical fertilizers is cause for concern for the safety of food and sustainable production. It is believed that organic farming by reverting to the use of manures, green manures, urban waste, rural wastes, etc. can bring eco-friendliness and sustainability to agriculture. Organic farming is a production of crops that avoids or largely excludes the use of synthetically compound fertilizers, pesticides, growth regulators and livestock feed additives. To the maximum extent feasible, organic farming systems rely upon crop rotation, crop residues, animal manures, legumes, green manures, off-farm organic wastes, mechanical cultivation, mineral bearing rocks and aspects of biological pest control to maintain, soil productivity and to supply plant nutrients and to control insects, weeds and other pests.

Organic farming system in India is not new and is being followed from ancient time. It is a method of farming system which primarily aimed at cultivating the land and raising crops in such a way, as to keep the soil alive and in good health by use of organic wastes (crop, animal and farm wastes, aquatic wastes) and other biological materials along with beneficial microbes (biofertilizers) to release nutrients to crops for increased sustainable production in an eco-friendly pollution free environment.

As per the definition of the United States Department of Agriculture (USDA) study team on organic farming “organic farming is a system which avoids or largely excludes the use of synthetic inputs (such as fertilizers, pesticides, hormones, feed additives etc) and to the maximum extent feasible rely upon crop rotations, crop residues, animal manures, off-farm organic waste, mineral grade rock additives and biological system of nutrient mobilization and plant protection”.

FAO suggested that “Organic agriculture is a unique production management system which promotes and enhances agro-ecosystem health, including biodiversity, biological cycles and soil biological activity, and this is accomplished by using on-farm agronomic, biological and mechanical methods in exclusion of all synthetic off-farm inputs”.

Objectives

Organic farming aims to:

• Increase long-term soil fertility.

• Control pests and diseases without harming the environment.

• Ensure that water stays clean and safe.

• Use resources which the farmer already has, so the farmer needs less money to buy farm inputs.

• Produce nutritious food, feed for animals and high quality crops to sell at a good price.

Importance of organic farming

With the increase in population our compulsion would be not only to stabilize agricultural production but to increase it further in sustainable manner. The scientists have realized that the ‘Green Revolution’ with high input use has reached a plateau and is now sustained with diminishing return of falling dividends. Thus, a natural balance needs to be maintained at all cost for existence of life and property. The obvious choice for that would be more relevant in the present era, when these agrochemicals which are produced from fossil fuel and are not renewable and are diminishing in availability. It may also cost heavily on our foreign exchange in future.

 Protecting the long term fertility of soils by maintaining organic matter levels, encouraging soil biological activity, and careful mechanical intervention  Providing crop nutrients indirectly using relatively insoluble nutrient sources which are made available to the plant by the action of soil micro-organisms  Nitrogen self-sufficiency through the use of legumes and biological nitrogen fixation, as well as effective recycling of organic materials including crop residues and livestock manures  Weed, disease and pest control relying primarily on crop rotations, natural predators, diversity, organic manuring, resistant varieties and limited (preferably minimal) thermal, biological and chemical intervention  The extensive management of livestock, paying full regard to their evolutionary adaptations, behavioural needs and animal welfare issues with respect to nutrition, housing, health, breeding and rearing  Careful attention to the impact of the farming system on the wider environment and the conservation of wildlife and natural habitats

Organic farming - Relevance to Indian Agriculture

The growth of organic agriculture in India has three dimensions and is being adopted by farmers for different reasons. First category of organic farmers are those which are situated in no-input or low-input use zones, for them organic is a way of life and they are doing it as a tradition (may be under compulsion in the absence of resources needed for conventional high input intensive agriculture). Second category of farmers are those which have recently adopted the organic in the wake of ill effects of conventional agriculture, may be in the form of reduced soil fertility, food toxicity or increasing cost and diminishing returns. The third category comprised of farmers and enterprises which have systematically adopted the commercial organic agriculture to capture emerging market opportunities and premium prices. While majority of farmers in first category are traditional (or by default) organic they are not certified, second category farmers comprised of both certified and un- certified but majority of third category farmers are certified. These are the third category commercial farmers which are attracting most attention. The entire data available on organic agriculture today, relates to these commercial organic farmers

There are three categories of opinions about the relevance of organic farming for India. The first one simply dismisses it as a fad or craze. The second category, which includes many farmers and scientists, opines that there are merits in the organic farming but we should proceed cautiously considering the national needs and conditions in which Indian agriculture functions. They are fully aware of the environmental problems created by the conventional farming. But many of them believe that yields are lower in organic cultivation during the initial period and also the cost of labour tends to increase therein. The third one is all for organic farming and advocates its adoption wholeheartedly. They think that tomorrow's ecology is more important than today's conventional farm benefits. However, among many a major reservation, the profitability of organic farming vis a vis conventional farming, is the crucial one from the point of view of the Indian farmers, particularly the small and marginal. Organic farming involves management of the agro-eco system as autonomous, based on the capacity of the soil in the given local climatic conditions. In spite of the ridicule poured out on organic farming by many, it has come to stay and is spreading steadily but slowly all over the world. India has been very slow to adopt it but it has made Inroads into our conventional farming system. The relevance and need for an eco-friendly alternative farming system arose from the ill effects of the chemical farming practices adopted worldwide during the second

6 half of the last century. The methods of farming evolved and adopted by our forefathers for centuries were less injurious to the environment. People began to think of various alternative farming systems based on the protection of environment which in turn would increase the welfare of the humankind by various ways like clean and healthy foods, an ecology which is conducive to the survival of all the living and non-living things, low use of the non-renewable energy sources, etc. Many systems of farming came out of the efforts of many experts and laymen. However, organic farming is considered to be the best among all of them because of its scientific approach and wider acceptance all over the world.

Land and water management

Benefits of improved land and water management practices to farmers and rural economies include increased agricultural productivity (higher yields), increased income and employment opportunities from agriculture, and increased resilience to climate change and associated extreme weather events—such as water scarcity, intense rainfall, or droughts. These benefits occur because these management practices: Increase soil organic matter, Improve soil structure, Reduce soil erosion, Increase water filtration, Increase efficiency of water use, Replenish soil nutrients, Increase efficiency of nutrient uptake.

Land Management

 Nutrient recycling  Crop rotation  Application of biopesticides & Biofertilizers  Effective waste management - Composting  Manure management  Integrated weed & pest management

Water management

Scarcity of water for agriculture is a common phenomenon in many countries. In some regions it is almost impossible to grow crops without irrigation. Even in areas with large amounts of rainfall in the rainy season, crops may get short of water during dry periods. Organic farming aims at optimising the use of on-farm resources and at a sustainable use of natural resources. Active water retention, water harvesting and storing of water are important

7 practices, especially for organic farmers. Organic farmers know that it is more important to first improve the water retention and the infiltration of water into the soil.

 Keep soil moisture: During dry periods, some soils are more and some are less in a position to supply crops with water. The ability of a soil to absorb and store water largely depends on the soil composition and on the content of organic matter. Soils rich in clay can store up to three times more water than sandy soils. Soil organic matter acts as storage of water, just like a sponge. Therefore, crop residue or a cover crop protects the soil, prevents crusting on the surface, and slows runoff. Roots, earthworms and other soil life maintain cracks and pores in the soil. Less water runs off, and more sinks into the soil.  Reduce evaporation: A thin layer of mulch can considerably reduce the evaporation of water from the soil. It shades the soil from direct sunlight and prevents the soil from getting too warm. Shallow digging of the dry top soil can help to reduce the drying up of the soil layers beneath (it breaks the capillary vessels). A better retention of water within the soil saves costs on irrigation.  Better use of season’s rainfall: Ripping during the dry season allows farmers to plant earlier – right at the start of the rains.

Approaches for water conservation

Attention: A green manure or cover crop is not always a suitable way of reducing evaporation from the soil, due that they also use water. In dry areas, you should consider using other types of mulch, such as crop residues or plant remains brought in from outside the field. That will help conserve moisture in the soil where it can be used by the crop.

Harvesting water a) Increasing infiltration

During strong rains, only a part of the water infiltrates into the soil. A considerable part flows away as surface runoff, thus being lost for the crop. In order to get as much of the available rainwater into the soil, the infiltration of rainwater needs to be increased.

Increasing the infiltration

Most important for achieving a high infiltration is to maintain a topsoil with a good soil structure containing many cavities and pores, e.g. from earthworms. Cover crops and

9 mulch application are suitable to create such a favourable top soil structure. Further, they help to slow down the flow of water, thus allowing more time for the infiltration.

Some techniques to harvest water include:

 Planting pits

Planting pits (known as zai in Burkina Faso and tassa in Niger) are hand-dug circular holes which collect water and store it for use by the crop. Each pit is about 20 cm across and 20 cm deep. After planting, the holes are left partly open so they collect water. Planting pits take a lot of work to dig when the soil is dry. But they produce good yields in areas where otherwise crops might die because of a lack of water. Once made, the pits can be used again, season after season. Leave the soil covered, and add compost or fertilizer to the pits to increase their fertility.

Zai holes with sorghum plants - typical of the Sahel

 Contour bunds and catchment strips

In areas with low rainfall, there may not be enough water to grow a crop over the whole area. On gentle slopes (less than 3%), one possibility is to use contour bunds and catchment strips. Catchment strips are areas where no crops are planted. When rain falls on this ground, it runs downslope and is trapped by the contour bund. Plant rows of crops behind the bund to use this water. This can produce a good yield even with very little rain. Mulch the cultivated areas with crop residues to prevent erosion, help water sink in, and slow evaporation.

The picture below shows an example of a farmer in Botswana, who makes his cropped strips 0,8–1 m wide a 3,3 m apart. He subsoils these strips using a tractor-powered subsoiler to a depth of 0,7 m. He shapes the land between the strips so it slopes towards the cropped strips, so rainwater will flow towards the crop. He plants two rows of maize in each strip, and sows a cover crop such as cowpea in between the strips. The strips are permanent: they can be used to grow crops season after season. The soil in the strips gradually improves in fertility as crop residues accumulate there. Rotating maize with a legume crop will improve the soil fertility further. The farmer has been able to grow up to 6 t/ha of maize with less than 400 mm/season of rain.

Maize in permanent strips

 Road catchments

Water from roads – and from other unproductive areas such as paths and homestead compounds – can be channelled onto fields. It may be possible to divert water from structures that already exist, such as the ditches below fanyajuu terraces. Or special bunds can be built around fields close to the road. Another possibility is to direct the water into a pond, which can be used to irrigate crops.

Contour bunds and catchment strips

Rainwater harvesting using a road catchment

 Half-moon microcatchments

Half-moon microcatchments are small, semicircular earth bunds. They are quite common on the desert margins of the Sahel, where they are called “demilunes”. The halfmoons catch water flowing down a slope. Crops such as sorghum, millet and cowpeas can be planted in the lower portion of the halfmoons. Half-moons are helpful to rehabilitate degraded land.

b) Water Storage

Excess water in the rainy season may be made use of during dry periods. There are many possibilities of storing rainwater for irrigation, but most of them are labouring intensive or costly. Storing water in ponds has the advantage that fish may be grown, but water is likely to be lost through infiltration and evaporation. The construction of water tanks may avoid these losses, but needs appropriate construction materials. To decide whether or not to build water storage infrastructure, the benefits should be weighed against the costs, including the loss of arable land.

Drip Irrigation Systems

The major factors that determine the necessity of irrigation are the selection of crops and an appropriate cropping system. Obviously, not all crops (and not even all varieties of the

13 same crop) require the same amount of water, and not all need water over the same period of time. Some crops are very resistant to drought while others are highly susceptible. Deep rooting crops can extract water from deeper layers of soil and hence they are less sensitive to temporary droughts. With the help of irrigation, many crops can nowadays be grown outside their typical agro-climatic region. This may cause not only the above mentioned negative impacts, but also some advantages. It may make it possible to cultivate land which would otherwise be unsuitable for agriculture without irrigation. Or the cultivation of sensitive crops can be shifted into areas with less pest or disease pressure. There are irrigation systems of higher or lower efficiency and with more or less negative impact. If irrigation is necessary, organic farmers should carefully select a system, which is does not overexploit the water source, does not harm the soil and has no negative impact on plant health.

One promising option are drip irrigation systems. From a central tank, water is distributed through thin perforated pipes directly to the single crop plants. There is a continuous but very light flow of water, thus allowing sufficient time to infiltrate in the /root zone of the crops. In this way, a minimum of water is lost and the soil is not negatively affected.

Drip irrigation

The establishment of drip irrigation systems can be quite costly. However, some farmers have developed low cost drip irrigation systems from locally available materials. Whatever irrigation system the farmer chooses, he will reach higher efficiency if it is combined with accompanying measures for improving the soil structure and the water retention of the soil, as described above.

Soil fertility

‘Soil fertility’ can be considered to be a measure of the soil’s ability to sustain satisfactory crop growth, both in the short- and longer-term. Organic farming recognises the soil as being central to a sustainable farming system. Soil fertility is determined by a set of interactions: Organic matter is essential for soil fertility. It maintains good soil physical conditions (e.g. soil structure, aeration and water holding capacity). It also contains most of the soil reserve of nitrogen (N) and large proportions of other nutrients such as phosphorus (P) and sulphur (S). Important: soil fertility is markedly affected by quantity and quality (type) of organic matter.

Organic rotations avoid inputs of water soluble (‘readily plant available’) nutrients. Organic farming therefore relies on: Release (‘mineralisation’) from organic residues or from native soil sources. Solubilisation of insoluble fertiliser sources (e.g. rock phosphate). Here, soil organisms (e.g. bacteria, fungi, earthworms and a whole range of organisms - the soil microflora, macro- and micro-fauna) are an essential part of the system, helping to release and recycle nutrients. Organic farming relies on sound crop rotations to include fertility building and fertility depleting stages, returns of crop residues, nitrogen fixation by legumes/Rhizobium, nutrient retention by green manures and effective use of manures/composts. Certain other materials, which are essentially slow release nutrient forms, are also permissible under various organic certification schemes. The emphasis is clearly on efficient nutrient cycling, especially as the import of manure on to organic farms is being looked upon less favourably. Organic management should aim to bring about are: An increase in soil nutrient reserves, change in processes of soil nutrient supply, changes to the soil physical attributes.

Nutrient recycling

Fertility building

• Rotations rely on fertility building.

• Legumes are the main source of nitrogen.

• Manures/composts are valuable sources of nutrients.

• It is essential to minimise losses of nutrients to the wider environment.

It is especially important to minimise losses of nutrients from the soil to the wider environment. This helps to maintain the efficiency of the organic system. Nitrogen Organic farming aims to be self-sufficient in N through fixation of atmospheric nitrogen (N2), recycling of crop residues and careful management and application of manures and composts. As well as legume-based leys, organic rotations often include an extra N boost by growing a legume (for example, field beans or peas) during the fertility depleting phase. Nitrogen supply to the following crops relies on mineralisation of the residues that have been accumulated during the fertility building phase. Captured N can also be returned to the soil as manure, either directly by grazing animals or indirectly in handled manure produced by animals that have been fed on leguminous forage or grains exported from the field.

Managing nutrient supply

• Nutrient management is one of the main challenges facing the organic farmer.

• In the short-term, the problem is supplying sufficient nutrients to the crop at the correct point in its development to achieve economically viable yields.

• In the long-term, the challenge is to balance inputs and off takes of nutrients to avoid nutrient rundown or environmental pollution.

• Both of these goals must be achieved in the most part through the management of organic matter. Within most organic systems, there are two main aspects to nutrient management:

• The fertility building ley, containing legumes to add N to the system.

• Manures used to redistribute nutrients around the farm. Nutrients, other than N, are imported onto the farm mainly in bought-in feed and animal bedding, though other sources such as green waste compost and permitted fertilisers may be important in some systems.

An alternative strategy is to add the manure to other parts of the rotation. The N will boost cash crop yield, while the P and K will still be available to the ley. The use of manure containing a high proportion of N in readily available form, such as slurry or poultry manure, is particularly detrimental to N fixation. The least detrimental is composted FYM, with a small proportion of N in an available form but retaining good P and K availability. Cutting and removing plant material (as silage, for instance) also promotes N fixation, when compared with grazing or cutting and mulching, as it removes N from the field. Though this means there is less N left for following cash crops, the N removed can be recycled back into the field in manure. Cutting leguminous plant and leaving the material in the field as mulch will add N rich material back to the soil and suppress the total amount of N fixed. However, this management strategy can be important for weed management.

Manure management

The main route of entry for nutrients brought onto the farm is usually via animal feed and bedding. Animal manure provides an important method for redistributing nutrients around the farm, particularly N, P, K, S and Mg. Manure also supplies valuable organic matter. Important: some nutrients in manure are all too easily lost, causing loss of a valuable resource and environmental pollution. Despite the obvious importance of manure to the organic farmer, there is plenty of scope for improved management on many organic farms. Fresh manure, especially slurry and poultry manure, contains a considerable proportion of N in readily available (principally ammonium - N) forms, which can be easily and rapidly lost to the atmosphere. Similarly, nutrients (particularly N and K) can be washed out by rainwater. Both ammonia and nitrate losses can cause environmental pollution as well as representing a loss of N that could be used by the crop. Effective manure management can minimise nutrient losses and maximise the benefits to the crop. There are two main treatment options available, actively composting and stacking for solid manure, and aerating slurries. For slurry, there is the additional option of mechanical separation, which can reduce the volume of material to be transported and enable irrigation of the separated liquid. Organic standards encourage the active composting of manure and aeration of slurry, however, on

17 many farms this does not occur. Both approaches to dealing with manure have their merits and problems as far as nutrient management is concerned.

Effective composting of solid manures and aeration of slurry has a number of benefits:

• Reduced odours

• Weed seeds and pathogens killed

• Reduced volume of material

• Production of a more uniform product

• Nitrogen stabilised in an organic form (solid manure)

Green waste compost is a good source of P, K and organic matter, but its availability is limited and cost can be high. Where a more specific need is identified, such as correcting low soil P status, it is probably best to go for a specific product, such as rock phosphate. Most of these supplementary nutrient sources have relatively low availability and so should be regarded as part of long-term nutrient planning rather than a short-term yield boosting solution. The most important soil parameter for guaranteeing nutrient supply to the crop is soil pH. Even when all plant nutrients are present in sufficient quantities in the soil, if the pH is not maintained at the right level (6.0-7.0) the crop will display nutrient deficiency symptoms and will not achieve its yield potential. This deficiency is partly due to the fact that in acidic conditions (low pH, below 5.5), soil biological activity is reduced, thereby slowing the release of nutrients. Also, at either end of the pH scale some major and minor nutrients become unavailable to the crop. Other effects of low pH or acidity include deteriorating soil structure, reduced crop quality, reduced fertiliser efficiency, increased nutrient losses, and deterioration of grass swards. Some soils are naturally rich in lime never need liming.

Other types of organic matter, such as FYM and crop residues will also help improve soil structure, though stabilised organic matter such as compost will have a smaller (though more long-term) effect. Management of soil structure is crucial to maintain good crop growth, particularly in organic systems where fertilisers and biocides cannot be used to

18 compensate for effects of bad structure. Careful cultivations, along with regular additions of fresh organic matter, should ensure that good structure is maintained.

Effective waste management is obviously a key to nutrient cycling on organic farms. However complete recycling is limited by the prohibition of the use of sewage sludge because of current concerns over the introduction of potentially toxic elements, organic pollutants and disease transmission. In addition, the current global market, in which food is transported large distances from the farm, results in a significant export of nutrients. These nutrients must be replaced otherwise, soil is impoverished and the system unsustainable.

Phosphorus and potassium-In mixed and animal-based systems, animal feeds and bedding represent relatively large inputs of P and K to organic farms. Anynecessary additional P and K is applied strategically within the rotation, with one application of rock phosphate expected to supply P for a number of following crops. However, organic farming seeks to optimise the recycling of P and K and to keep imports as small as possible. In animal-based and mixed systems, good manure management is therefore essential. Manure and slurry are used to redistribute nutrients around the farm. However, the grazing patterns of livestock, such as ‘camping’ under trees, in the lea of hedges and at fixed feed troughs, can increase the spatial heterogeneity of P and K returns, which may persist for many years. Phosphorus dominantly occurs in organic forms in manures, while K is found in soluble forms; large leaching losses of K can therefore occur during manure storage and composting.

Crop rotation

It is the practice of growing a series of dissimilar or different types of crops in the same area in sequenced seasons. It is done so that the soil of farms is not used to only one type of nutrient. It helps in reducing soil erosion and increases soil fertility and crop yield. Growing the same crop in the same place for many years in a row disproportionately depletes the soil of certain nutrients. With rotation, a crop that leaches the soil of one kind of nutrient is followed during the next growing season by a dissimilar crop that returns that nutrient to the soil or draws a different ratio of nutrients. In addition, crop rotation mitigates the buildup of pathogens and pests that often occurs when one species is continuously cropped, and can also improve soil structure and fertility by increasing biomass from varied root structures. Crop rotation is used in both conventional and organic farming systems.

Farmers are required to implement a crop rotation that maintains or builds soil organic matter, works to control pests, manages and conserves nutrients, and protects against erosion. Producers of perennial crops that aren’t rotated may utilize other practices, such as cover crops, to maintain soil health. In addition to lowering the need for inputs by controlling for pests and weeds and increasing available nutrients, crop rotation helps organic growers increase the amount of biodiversity on their farms. Some studies point to increased nutrient availability from crop rotation under organic systems compared to conventional practices as organic practices are less likely to inhibit of beneficial microbes in soil organic matter.

Intercropping

Multiple cropping systems, such as intercropping or companion planting, offer more diversity and complexity within the same season or rotation, for example the three sisters. An example of companion planting is the inter-planting of corn with pole beans and vining squash or pumpkins. In this system, the beans provide nitrogen; the corn provides support for the beans and a "screen" against squash vine borer; the vining squash provides a weed suppressive canopy and discourages corn-hungry raccoons.

Double-cropping is common where two crops, typically of different species, are grown sequentially in the same growing season, or where one crop (e.g. vegetable) is grown continuously with a cover crop (e.g. wheat).[3] This is advantageous for small farms, who often cannot afford to leave cover crops to replenish the soil for extended periods of time, as larger farms can.[6] When multiple cropping is implemented on small farms, these systems can maximize benefits of crop rotation on available land resources.[6]

Benefits

Agronomists describe the benefits to yield in rotated crops as "The Rotation Effect". There are many found benefits of rotation systems: however, there is no specific scientific basis for the sometimes 10-25% yield increase in a crop grown in rotation versus monoculture. The factors related to the increase are simply described as alleviation of the negative factors of monoculture cropping systems. Explanations due to improved nutrition; pest, pathogen, and weed stress reduction; and improved soil structure have been found in some cases to be correlated, but causation has not been determined for the majority of cropping systems.

Other benefits of rotation cropping systems include production cost advantages. Overall financial risks are more widely distributed over more diverse production of crops and/or livestock. Less reliance is placed on purchased inputs and over time crops can maintain production goals with fewer inputs. This in tandem with greater short and long term yields makes rotation a powerful tool for improving agricultural systems.

Soil organic matter

The use of different species in rotation allows for increased soil organic matter (SOM), greater soil structure, and improvement of the chemical and biological soil environment for crops. With more SOM, water infiltration and retention improves, providing increased drought tolerance and decreased erosion. Soil organic matter is a mix of decaying material from biomass with active microorganisms. Crop rotation, by nature, increases exposure to biomass from sod, green manure, and a various other plant debris. The reduced need for intensive tillage under crop rotation allows biomass aggregation to lead to greater nutrient retention and utilization, decreasing the need for added nutrients. With tillage, disruption and oxidation of soil creates a less conducive environment for diversity and proliferation of microorganisms in the soil. These microorganisms are what make nutrients available to plants. So, where "active" soil organic matter is a key to productive soil, soil with low microbial activity provides significantly fewer nutrients to plants; this is true even though the quantity of biomass left in the soil may be the same.

Soil microorganisms also decrease pathogen and pest activity through competition. In addition, plants produce root exudates and other chemicals which manipulate their soil environment as well as their weed environment. Thus rotation allows increased yields from nutrient availability and competitive weed environments.

Carbon sequestration

Studies have shown that crop rotations greatly increase soil organic carbon (SOC) content, the main constituent of soil organic matter. Carbon, along with hydrogen and oxygen, is a macronutrient for plants. Highly diverse rotations spanning long periods of time have shown to be even more effective in increasing SOC, while soil disturbances (e.g. from tillage) are responsible for exponential decline in SOC levels. In Brazil, conservation to no- till methods combined with intensive crop rotations has been shown an SOC sequestration

21 rate of 0.41 tonnes per hectare per year. In addition to enhancing crop productivity, sequestration of atmospheric carbon has great implications in reducing rates of climate change by removing carbon dioxide from the air.

Nitrogen fixing

Rotating crops adds nutrients to the soil. Legumes, plants of the family Fabaceae, for instance, have nodules on their roots which contain nitrogen-fixing bacteria called rhizobia. It therefore makes good sense agriculturally to alternate them with cereals (family Poaceae) and other plants that require nitrates.

Pathogen and pest control

Crop rotation is also used to control pests and diseases that can become established in the soil over time. The changing of crops in a sequence decreases the population level of pests by

(1) interrupting pest life cycles and

(2) interrupting pest habitat

Plants within the same taxonomic family tend to have similar pests and pathogens. By regularly changing crops and keeping the soil occupied by cover crops instead of lying fallow, pest cycles can be broken or limited, especially cycles that benefit from overwintering in residue. For example, root-knot nematode is a serious problem for some plants in warm climates and sandy soils, where it slowly builds up to high levels in the soil, and can severely damage plant productivity by cutting off circulation from the plant roots. Growing a crop that is not a host for root-knot nematode for one season greatly reduces the level of the nematode in the soil, thus making it possible to grow a susceptible crop the following season without needing soil fumigation. This principle is of particular use in organic farming, where pest control must be achieved without synthetic pesticides.

Weed management

Integrating certain crops, especially cover crops, into crop rotations is of particular value to weed management. These crops crowd out weed through competition. In addition, the sod and compost from cover crops and green manure slows the growth of what weeds are

22 still able to make it through the soil, giving the crops further competitive advantage. By removing slowing the growth and proliferation of weeds while cover crops are cultivated, farmers greatly reduce the presence of weeds for future crops, including shallow rooted and row crops, which are less resistant to weeds. Cover crops are, therefore, considered conservation crops because they protect otherwise fallow land from becoming overrun with weed.

This system has advantages over other common practices for weeds management, such as tillage. Tillage is meant to inhibit growth of weeds by overturning the soil; however, this has a countering effect of exposing weed seeds that may have gotten buried and burying valuable crop seeds. Under crop rotation, the number of viable seeds in the soil is reduced through the reduction of the weed population.

Preventing soil erosion

Crop rotation can significantly reduce the amount of soil lost from erosion by water. In areas that are highly susceptible to erosion, farm management practices such as zero and reduced tillage can be supplemented with specific crop rotation methods to reduce raindrop impact, sediment detachment, sediment transport, surface runoff, and soil loss.

Biodiversity

Increasing the biodiversity of crops has beneficial effects on the surrounding ecosystem and can host a greater diversity of fauna, insects, and beneficial microorganisms in the soil. Some studies point to increased nutrient availability from crop rotation under organic systems compared to conventional practices as organic practices are less likely to inhibit of beneficial microbes in soil organic matter, such as arbuscular mycorrhizae, which increase nutrient uptake in plants. Increasing biodiversity also increases the resilience of agro- ecological systems.

Farm productivity

Crop rotation contributes to increased yields through improved soil nutrition. By requiring planting and harvesting of different crops at different times, more land can be farmed with the same amount of machinery and labour.

Organic farming and National economy

According to actual field data, organic farming is more economically successful than the modelers predict. The stated assumptions of the models seem reasonable. Therefore, examination of the unstated assumptions may be instructive, since there are differences between the two systems that are difficult to incorporate into models. The models assumed that soil structure, infiltration rates, and erosion rates were the same for organic and conventional agriculture, or that any differences had no economic consequences. Some organic farmers claim their soils have better tilth and less compaction. They also claim that they use less power and operate their tractors in a higher gear, thereby saving fuel. These claims, although plausible, have not been sufficiently tested.

Changes in soil structure, coupled with improved ground cover, decreased runoff by about 10 to 50 percent and increased infiltration by about 10 to 25 percent. All these factors combined to reduce soil erosion on organic fields by at least two-fifths, and sometimes over four-fifths. It is difficult to place a monetary value on the water lost as runoff and the nutrients contained in the eroded soil. In part, they are just displaced to other locations on the farm, where they remain available for crop production. Some nutrients are present in excess of crop needs and some are unavailable biochemically. Nevertheless, there may be a significant difference between organic and conventional farms in the costs of replacing needed nutrients and water.

Vulnerability to natural events may be a critical factor in comparing the performance of organic and conventional farms. During the conversion period, organically produced crops are vulnerable to weeds and nitrogen deficiences. However, once organic practices are established, the crops are often less vulnerable to drought and other natural disasters than conventionally grown crops. Organically farmed soils absorb more of the available rainfall, providing protection from drought. Because organic farmers grow a greater diversity of crops, the entire production on a farm is not vulnerable to the same pests or seasonal weather events. If there is a total crop failure, organic farmers suffer fewer economic losses because they have invested less in purchased inputs.

The diversity of crops on organic farms can have other economic benefits. Diversity provides some protection from adverse price changes in a single commodity. Diversified farming also provides a better seasonal distribution of inputs. A corn farmer might require

24 two tractors to plant all his land during the short corn-planting season. The tractors are then underutilized during the remainder of the year. An organic farm with the same total area would probably have less land in corn, so one tractor might be sufficient. The same tractor could then be used during other seasons to produce wheat, hay, and other crops that have staggered planting and harvest dates. Likewise, labor is more fully utilized. However, organic farms require more intensive management than specialized conventional farms.

Organic farmers need to borrow less money than conventional farmers for two reasons. First, organic farmers buy fewer inputs such as fertilizer and pesticides. Second, costs and income are more evenly distributed throughout the year on diversified organic farms. For example, profits from July's wheat harvest can buy fuel for the corn harvest, reducing the need to borrow for the corn harvest. Organic farmers have complained that they are discriminated against by lenders, a possible economic disadvantage of organic farming. However, Blobaum (1983) concluded that this problem is more perceived than real.

Organic farmers have less need for irrigation because they use more crop rotations and because of higher soil permeability. Organic growers tend to be less capital intensive, so tax breaks are less advantageous to them.

Future trends

The relative economic performance of organic farming and conventional farming is sensitive to the ratio of input costs to the value of outputs. Both organic and conventional farmers are vulnerable to fluctuations in both input and output prices, but the effect of a given change will differ between the two farming systems.

The future of commodity prices is not clear. However, changes in commodity prices can be expected to have greater impacts on conventional than organic farmers. Conventional producers have higher average yields for most grain crops. Therefore, assuming constant production costs, price increases will increase the net returns of conventional farmers by a greater proportion than those of organic farmers. Conversely, price decreases will decrease conventional returns by a greater proportion than organic returns. Differential price changes (increases in some commodity prices and decreases in others) would also tend to have effects of greater magnitude, whether positive or negative, on conventional farmers, since they

25 depend on fewer crops for their income. Because organic systems are more diversified, the effects of differential price changes on income would partially offset each other.

Increases in the cost of variable inputs would be less damaging to organic farmers because they purchase fewer inputs. The most likely price increases in the near future will be for energy, with consequent increases in the price of synthetic nitrogen fertilizers. Organic farmers use less energy than conventional farmers, primarily because they use less synthetic nitrogen.

Farmers may face increasing pressure from governments to control the movement of sediment, pesticides, and nutrients from farmland to the off-farm environment. Organic farming controls erosion and reduces or eliminates the use of pesticides and highly soluble forms of nitrogen. Therefore, organic farmers are already controlling pollution. If conventional farmers are forced through regulation or other policy instruments to control runoff, organic techniques and reduced tillage possibly would be their cheapest alternatives.

Finally, research on organic farming can improve the economic performance of organic methods. The lack of reliable information on problems specific to organic farming, such as non-chemical weed control, is a serious barrier to its adoption. Government- sponsored agricultural research has focused on chemical-intensive agriculture, leaving organic farmers to rely on the organic industry or a small number of organic research groups for information. Intensive research on agricultural chemicals has been conducted for four decades, but organic research is in its infancy. Therefore, the economic benefits to farmers from an incremental investment in organic research may be greater than from a corresponding investment in chemically-oriented research.

UNIT II

Methods of organic farming

Organic farming can be explained as an agricultural method wherein the following techniques are used:

 Crop Rotation: A technique to grow various kinds of crops in the same area, according to different seasons, in a sequential manner  Green Manure: Refers to the dying plants that are uprooted and stuffed into the soil in order to make them act as a nutrient for the soil to increase its quality  Biological Pest Control: A method in which living organisms are used to control pests, without or with limited use of chemicals  Compost: Highly rich in nutrients, this is a recycled organic matter used as a fertilizer in the agricultural farms

The reason why organic agriculture is enforced in many nations is because it minimizes the use of various harmful chemicals that have hazardous effects on crops in the field. Here, there is more focus on using natural ways to enhance the quality of soil and the cultivated crops. Organic agriculture is nothing more than a modernization in agriculture. It is a combination of science, technology and nature. Following are the different methods that combine together to form organic agriculture:

Crop Diversity

Earlier, Monoculture was the only practice used in the agricultural fields wherein only one type of crop was harvested and cultivated in a particular location. However, in the recent world, Polyculture has come into the picture wherein different kinds of crops are harvested and cultivated in order to meet the increasing crop demand and produce the required soil microorganisms.

Soil Management

After the season of cultivation has been conducted, the soil loses its nutrients and becomes less in quality. Rather than using harmful chemicals to enhance this soil, organic

27 agriculture focuses on implementing natural ways to not only increase the health of soil but also keep the nature and human health unharmed. One of the best examples of natural ways to enhance soil is the use of bacteria that is present in animal waste. This bacterium helps in making the soil nutrients more productive; much higher as compared to the chemical containing liquids.

Weed Management

“Weed”, in simple words, is nothing but the unwanted plant that grows in agricultural fields. However, in organic agriculture, there is more focus on suppressing the weed rather than eliminating it completely.

The two most widely used weed management techniques are:

 Mulching – a process wherein plastic films are used in order to block the growth of weed  Mowing and cutting – wherein there is a removal of weeds’ top growth

Controlling other organisms

While certain organisms prove to be beneficial to the health of the agricultural farm, there are many others that hamper the field. Hence, the growth of such organisms needs to be controlled to protect the soil and crops. Out of the long list, following are the three most commonly used and important ways of controlling other organisms in organic agriculture:

 Encouraging ladybugs, minute pirate bugs and other such predatory beneficial insects that feast on pests and fly away from the farm  Using herbicides and pesticides that are natural or contain less chemical  Proper sanitization of the entire farm in order to keep it free from pests

Livestock

There can be no better place for the pet animals to get fresh air, food and a great exercise than the green farm. Since everything is preferred to be in a natural way, just like the animals were used as labor in the earlier times for plowing, organic agriculture encourages the use of domestic animals to increase the sustainability of the farm.

Organic agriculture is being conducted by many countries with the rejection of using techniques and chemicals that harm animals, crops, soil, environment and even the human health. Hence, such a process of agriculture should be encouraged since it acts as a protection shield to all the main factors that form the planet.

Advantages and applications of organic farming

Nutrition

The nutritional value of food is largely a function of its vitamin and mineral content. In this regard, organically grown food is dramatically superior in mineral content to that grown by modern conventional methods. Because it fosters the life of the soil organic farming reaps the benefits soil life offers in greatly facilitated plant access to soil nutrients.Healthy plants mean healthy people, and such better nourished plants provide better nourishment to people and animals alike.

Poison-free

A major benefit to consumers of organic food is that it is free of contamination with health harming chemicals such as pesticides, fungicides and herbicides. As you would expect of populations fed on chemically grown foods, there has been a profound upward trend in the incidence of diseases associated with exposure to toxic chemicals in industrialized societies.

Food Tastes Better

Animals and people have the sense of taste to allow them to discern the quality of the food they ingest. It comes as no surprise, therefore, that organically grown food tastes better than that conventionally grown. The tastiness of fruit and vegetables is directly related to its sugar content, which in turn is a function of the quality of nutrition that the plant itself has enjoyed. This quality of fruit and vegetable can be empirically measured by subjecting its juice to Brix analysis, which is a measure of its specific gravity (density). The Brix score is widely used in testing fruit and vegetables for their quality prior to export.

Food Keeps Longer

Organically grown plants are nourished naturally, rendering the structural and metabolic integrity of their cellular structure superior to those conventionally grown. As a result, organically grown foods can be stored longer and do not show the latter’s susceptibility to rapid mold and rotting.

Resistance to plants

It gives more resistance to drought condition, disease and pest Resistance to plants.

Organic farming relevance to pollution free environment

Air pollution and climate change

A major theme in organic practices is to operate in tight nutrient cycles to minimize losses to the air and water reserves. There is a reduction in air pollution not just from the lower carbon footprint but also from the absence of chemical sprays which get into the atmosphere. There have been tremendous amount of chemicals which are used to direct lands to yield only desired products and not pests and weeds. This is especially can be tracked after agricultural revolution through using planes and tanks of materials. Agriculture is both cause and victim of climate change. According to the Intergovernmental Panel on Climate Change (IPCC), the annual amount of greenhouse gases emitted by the agricultural sector is estimated about six giga-tonnes CO2 in 2005. This represents approximately 10-12% of total greenhouse gases. As a consequence, an organic farming system is only substitute to produce healthy products without any side effects locally (air pollution) and globally (climate change).

Water and soil pollution

Intensive aquaculture may leave substantial amount of nutrients and poisons to water bodies. Water pollution is largely associated with the use and discharge of water in both animal and plant farming. For instance, in a fish pond each time water is exchanged, wastewater is discharged to the surrounding surface waters. The wastewater carries a number of pollutants, reflected in the selected indicators. These pollutants ultimately stem from chemicals, fertilizers and feed added to the ponds. Therefore, in an organic farming, water

30 pollution is lower, as there is much reduced eutrophication of chemical inputs. Soil structure on organic farms is much better leading to less pollution from nitrate and is healthier for the crop plant, and that environmentally organic is better than the other forms and is chemical free.

Sustainable agriculture

Organic farming seems to be more appropriate as it considered the important aspects like sustainable. Agriculture is the most important sector for ensuring food security, alleviating poverty and conserving the vital natural resources that the world’s present and future generation will be entirely dependent upon for their survival and wellbeing, in the name of development, the environmental resources have been beyond comprehension. Acid rain, deforestation, depletion, smog due to automobiles and discharge of industrial pollution, soil degradation, depletion of ozone layer and discharge of toxic wastage by industrial units into rivers and oceans are some environmental problematic issues. Intensive use of inorganic fertilizers and pesticides has been an important tool in the drive for increased crop production. In fact more fertilizers consumption is a good indication of agricultural productivity but depletion of soil fertility is commonly observed in soils. Due to heavy use of chemical herbicides, pesticides and intensification of agricultural production during the past few decades has led to other harmful effects like nitrate in the ground water, contamination of fooding materials, eutrophication, stratospheric changes etc. High agricultural inputs are unlikely to be sustainable for very long unless the inputs are correctly judged in terms of both their quality and quantity. To escape from these harmful effects, the concept of organic farming was emerged from the conference of Atlanta in 1981. Organic Farming seems to be more appropriate as it considered the important aspects like sustainable natural resources and environment. It is a production system, which favors maximum use of organic materials like crop residues, FYM, compost, green manure, oil cakes, bio-fertilizers, bio-gas slurry etc. to improve soil health from the different experiment, microbial fertilizers like Rhizomic, Azotobacter, Blue green algae, Azolla etc. have increased the yield and also played important role for minimizing the harmful effect of pesticides and herbicides. Organic farming is a practical proposition for sustainable agriculture if adequate attention is paid to this issue. There is urgent need to involve more and more scientist to identify the thrust area of research for the development of eco-friendly production technology.

Marketing and Export

Organic food exports from India are increasing with more farmers shifting to organic farming. With the domestic consumption being low, the prime market for Indian organic food industry lies in the US and Europe. India has now become a leading supplier of organic herbs, organic spices, organic basmati rice, etc. RCNOS recently published a report tilted ‘Food Processing Market in India (2005)’. According to its research, exports amount to 53% of the organic food produced in India. This is considerably high when compared to percentage of agricultural products exported. In 2003, only 6-7% of the total agricultural produce in India was exported. Exports is driving organic food production in India: The increasing demand for organic food products in the developed countries and the extensive support by the Indian government coupled with its focus on agri-exports are the drivers for the Indian organic food industry. Organic food products in India are priced about 20-30% higher than non-organic food products. This is a very high premium for most of the Indian population where the per capita income is merely USD 800. Though the salaries in India are increasing rapidly, the domestic market is not sufficient to consume the entire organic food produced in the country. As a result, export of organic food is the prime aim of organic farmers as well as the government. The Indian government is committed towards encouraging organic food production. It allocated Rs. 100 crore or USD 22.2 million during the Tenth Five Year Plan for promoting sustainable agriculture in India. APEDA (Agricultural and Processed Food Export Development Authority) coordinates the export of organic food (and other food products) in India. The National Programme for Organic Production in India was initiated by the Ministry of Commerce. The programme provides standard for the organic food industry in the country. Since these standards have been developed taking into consideration international organic production standards such as CODEX and IFOAM, Indian organic food products are being accepted in the US and European markets. APEDA also provides a list of organic food exporters in India. Organic food costs in India are expected to decrease, driving further exports in future. Organic food production costs are higher in the developed countries as organic farming is labour intensive and labour is costly in these countries. However, in a country like India, where labour is abundant and is relatively cheap, organic farming is seen as a good cost effective solution to the increasing costs involved in chemical farming. Currently most of the organic farmers in India are still in the transition phase and hence their costs are still high. As these farmers continue with organic farming, the production costs are expected to reduce, making India as one of the most important producers of organic food.

Organic food products exported from India include the following:

• Organic Cereals: Wheat, rice, maize or corn

• Organic Pulses: Red gram, black gram

• Organic Fruits: Banana, mango, orange, pineapple, passion fruit, cashew nut, walnut

• Organic Oil Seeds and Oils: Soybean, sunflower, mustard, cotton seed, groundnut, castor

• Organic Vegetables: Brinjal, garlic, potato, tomato, onion

• Organic Herbs and Spices: Chili, peppermint, cardamom, turmeric, black pepper, white pepper, amla, tamarind, ginger, vanilla, clove, cinnamon, nutmeg, mace,

• Others: Jaggery, sugar, tea, coffee, cotton, textiles

Organic Food Consumption in India

Organic Food Consumption in India is on the rise. Some people believe that organic food is only a “concept” popular in the developed countries. They think that when it comes to organic food, India only exports organic food and very little is consumed. However, this is not true. Though 50% of the organic food production in India is targeted towards exports, there are many who look towards organic food for domestic consumption. ACNielsen, a leading market research firm, recently surveyed about 21,000 regular Internet users in 38 countries to find their preference for functional foods – foods that have additional health benefits. The survey revealed that India was among the top ten countries where healthy food, including organic food, was demanded by the consumers. The most important reason for buying organic food was the concern for the health of children, with over 66 percent parents preferring organic food to non-organic food. Though organic food is priced over 25 percent more than conventional food in India, many parents are willing to pay this higher premium due to the perceived health benefits of organic food. The increase in organic food consumption in India is evident from the fact that many organic food stores are spurring up in India. Today (2006) every supermarket has an organic food store and every large city in India has numerous organic food stores and restaurants. This is a huge change considering that the

33 first organic food store in Mumbai was started in 1997. What do Indian organic food consumers prefer? The pattern of organic food consumption in India is much different than in the developed countries. In India, consumers prefer organic marmalade, organic strawberry, organic tea, organic honey, organic cashew butter and various organic flours. However, the Indian organic food consumer needs education. There are many consumers who are unaware of the difference between natural and organic food. Many people purchase products labelled as Natural thinking that they are Organic. Further, consumers are not aware of the certification system. Since certification is not compulsory for domestic retail in India, many fake organic products are available in the market.

Certification

Organic certification is a certification process for producers of organic food and other organic agricultural products. In general, any business directly involved in food production can be certified, including seed suppliers, farmers, food processors, retailers and restaurants. Requirements vary from country to country, and generally involve a set of production standards for growing, storage, processing, packaging and shipping that include:

• avoidance of most synthetic chemical inputs (e.g. fertilizer, pesticides, antibiotics, food additives, etc), genetically modified organisms, irradiation, and the use of sewage sludge;

• use of farmland that has been free from synthetic chemicals for a number of years (often, three or more);

• keeping detailed written production and sales records (audit trail);

• maintaining strict physical separation of organic products from non-certified products;

• undergoing periodic on-site inspections.

In some countries, certification is overseen by the government, and commercial use of the term organic is legally restricted. Certified organic producers are also subject to the same agricultural food safety and other government regulations that apply to non-certified producers.

Purpose of certification

Organic certification addresses a growing worldwide demand for organic food. It is intended to assure quality and prevent fraud. For organic producers, certification identifies suppliers of products approved for use in certified operations. For consumers, "certified organic" serves as a product assurance, similar to "low fat", "100% whole wheat", or "no artificial preservatives".

Certification is essentially aimed at regulating and facilitating the sale of organic products to consumers. Individual certification bodies have their own service marks, which can act as branding to consumers. Most certification bodies operate organic standards that meet the National government's minimum requirements. Some certification bodies, certify to higher standards.

Certification & product labeling

In some countries, organic standards are formulated and overseen by the government. The United States, the European Union, Canada and Japan have comprehensive organic legislation, and the term "organic" may be used only by certified producers. Being able to put the word "organic" on a food product is a valuable marketing advantage in today's consumer market, but does not guarantee the product is legitimately organic. Certification is intended to protect consumers from misuse of the term, and make buying organics easy. However, the organic labeling made possible by certification itself usually requires explanation. In countries without organic laws, government guidelines may or may not exist, while certification is handled by non-profit organizations and private companies.

In India, APEDA regulates the certification of organic products as per National Standards for Organic Production. "The NPOP standards for production and accreditation system have been recognized by European Commission and Switzerland as equivalent to their country standards. Similarly, USDA has recognized NPOP conformity assessment procedures of accreditation as equivalent to that of US. With these recognitions, Indian organic products duly certified by the accredited certification bodies of India are accepted by the importing countries." In March 2000, the Ministry of Commerce launched NPOP (National Programme for Organic Production) design to establish national standards for organic products which could then be sold under the logo India Organic. For proper

35 implementation of NPOP, NAPP (National Accreditation Policy and Programme) has been formulated, with Accreditation Regulations announced in May 2001. These make it mandatory that all certification bodies whether internal or foreign operating in the country must be accredited by an Accreditation Agency. The regulations make provision for export, import and local trade of organic products. However, currently only the exports of organic products come under government regulations. Thus an agricultural product can only be exported as an organic product if it is certified by a certification body duly accredited by APEDA. Organic crop production, organic animal production, organic processing operations, forestry and wild products are the categories of products covered under accreditation.

Organic certification mark

A trademark “India Organic” will be granted on the basis of compliance with the National Standards for Organic Production (NSOP). Communicating the genuineness as well as the origin of the product, this trademark is owned by the Government of India. Only such exporters, manufacturers and processors whose products are duly certified by the accredited inspection and certification agencies, will be granted the license to use of the logo which would be governed by a set of regulations.

Accreditation

Accreditation is a process in which certification of competency, authority, or credibility is presented. Organizations that issue credentials or certify third parties against official standards are themselves formally accredited by accreditation bodies (such as UKAS); hence they are sometimes known as "accredited certification bodies". The accreditation process ensures that their certification practices are acceptable, typically meaning that they are competent to test and certify third parties, behave ethically and employ suitable quality assurance. One example of accreditation is the accreditation of testing laboratories and certification specialists that are permitted to issue official certificates of compliance with established standards, such as physical, chemical, forensic, quality, and security standards.

Accreditation in India

As per the National Programme for Organic Production (NPOP) an accreditation refers registration by the accreditation agency for certifying agency for certifying organic farms, products and processes as per the guidelines of the National Accreditation Policy and Programme for Organic Product.

NPOP programme in context of Indian accreditation scenario, defined the function of accreditation agencies like

• Prescribe the package of practices for organic products in their respective schedule;

• Undertake accreditation of inspection and certifying agencies who will conduct inspection and certify products as having been produced in accordance with NPOP;

• Monitor inspection made by the accredited inspection agencies;

• Lay down inspection procedures;

• Advise the National Steering Committee on Organic Production;

• Accept Accredited certification programmes if such programme confirm to National Standard;

• Accreditation Agencies Shall evolve accreditation criteria for inspection and/or certifying agencies and programme drawn up by such agencies for their respective area of operation and products;

• Accreditation agencies shall prepare an operating manual to assist accredited agencies to abide by such a manual must contain appropriate directions, documentation formats and basic agency and farm records for monitoring and authentication of adherence to the organic production programme;

• Eligible inspection and certification agencies implementing certification programmes will be identified by the Accreditation Agency.

UNIT III

Organic manure

Manures are plant and animal wastes that are used as sources of plant nutrients. They release nutrients after their decomposition. Manures can be grouped into bulky organic manures and concentrated organic manures based on concentration of the nutrients.

Bulky organic manures

Bulky organic manures contain small percentage of nutrients and they are applied in huge quantities. Farmyard manure (FYM), compost and green manure are the most important and widely used bulky organic manures. Use of bulky organic manures have several advantages: (1) they supply plant nutrients including micronutrients,

(2) they improve soil physical properties like structure, water holding capacity etc.,

(3) they increase the availability of nutrients,

(4) carbon dioxide released during decomposition acts as a CO2 fertilizer, and

(5) 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. Cattle manure is slow acting, bulky organic and however is a low analysis fertilizer, obtained from dung and urine of farm animals mixed with litter and other miscellaneous farm wastes.

An average well decomposed farmyard manure contains 0.5 % N, 0.2 % P2O5 and 0.5 percent K2O. The present method of preparing farmyard manure by the farmers is defective. Urine, which is wasted, contains one % nitrogen and 1.35 percent 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.

Quality and composition of FYM

The quality of manure and chemical composition in particular is highly variable depending upon the kind of animal, age and condition of the individual animal, quality and quantity of feed consumed, kind of litter used, collection and storage of manure

1) Kind of animal: The quality of manure depends on the class of manure viz., cattle, horse manure. Within the same class, quality varies according to the kind of animal, such as milch cattle, dry cattle, work cattle, breeding bulls etc. By and large the dung and urine from animals, which assimilates less (little) for their maintenance and production, will provide better quality manure.

2) Age and condition and individual animal: Growing animals, milch cattle, pregnant or carrying cattle utilize much of the ingredients in the feeds for building up their growing bodies, milk production and for the development of the embryo [calf]. Old or adult animals kept on light work or no work, utilize little from feeds and as such, most of nitrogen is voided through urine and dung. Eventually, the adult old cattle provide better manure.

3) Quality and quantity of feed consumed: Nutritious and protein rich feeds like oil cakes enriches the nitrogen content to the resulting manure than the bulky feeds like straw and green grass. Animals fed on concentrated feeds yield better quality manure.

4) Kind of litter used: The quality of manure depends to a considerable extent on the nature of litter used. Remnants of leguminous hays (Bhusa) give richer manure than usual straws.

5) Collection of manure: The method adopted for collection of dung, urine and litter primarily decide the quality of manure as the loss of nutrients particularly nitrogen occurs from the time urine and dung are voided by cattle. The quality of manure depends upon the methods of collection.

Goat Manure

The dropping of goats contains higher nutrients than farm yard 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

39 second method is sheep penning, wherein sheep and goats are allowed to stay overnight in the field and urine and fecal matter is added to the soil which is incorporated to a shallow depth by running blade harrow or cultivator.

Poultry Manure

The excreta of birds ferments 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.

Green Manure

Green un-decomposed plant material used as manure is called green manure. It is obtained in two ways: by growing green manure crops or by collecting green leaf (along with twigs) from plants grown in wastelands, field bunds and forest. Green manuring is growing in the field plants usually belonging to leguminous family and incorporating into the soil after sufficient growth. The plants that are grown for green manure are known as green manure crops. The most important green manure crops are sunnhemp, dhaincha, pillipesara, clusterbeans and Sesbania rostrata. Nitrogen fixation by leguminous green manure crops can be increased by application of phosphatic fertilizers. This phosphorus is available to succeeding crop after mineralization of the incorporated green manure crop. Application to the field, green leaves and twigs of trees, shrubs and herbs collected from elsewhere is known as green-leaf manuring. Forest tree leaves are the main sources for green-leaf manure. Plants growing in wastelands, field bunds etc., are another source of greenleaf manure. The important plant species useful for green-leaf manure are neem, mahua, wild indigo, glyricidia, Karanji (Pongamia glabra) calotropis, avise (Sesbania grandiflora), subabul and other shrubs. Several advantages accrue due to the addition of green manures. Organic matter and nitrogen are added to the soil. Growing deep rooted green-manure crops and their incorporation facilitates in bringing nutrients to the top layer from deeper layers. Nutrient availability increases due to production of carbon dioxide and organic acids during decomposition. Green manuring improves soil structure, increases water-holding capacity and decreases soil loss by erosion. Growing of green-manure crops in the off season reduces weed proliferation and weed growth. It helps in reclamation of alkaline soils. Root-knot nematodes can be controlled by green manuring. Concentrated organic manures Concentrated organic manures have higher nutrient content than bulky organic manure. The important concentrated organic manures are

40 oilcakes, bloodmeal, 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 ammonical nitrogen and nitrate nitrogen. These organic fertilizers are, therefore, relatively slow acting, but they supply available nitrogen for a longer period.

Composting

Vermicompost is the product or process of composting using various worms, usually red wigglers, white worms, and other earthworms, to create a heterogeneous mixture of decomposing vegetable or food waste, bedding materials, and Vermicast, also called worm castings, worm humus or worm manure, is the end-product of the breakdown of organic matter by an earthworms These castings have been shown to contain reduced levels of contaminants and a higher saturation of nutrients than do organic materials before vermicomposting Containing water-soluble nutrients, vermicompost is an excellent, nutrient- rich organic fertilizer and soil conditioner. This process of producing vermicompost is called vermicomposting.

One of the earthworm species most often used for composting is the Red Wiggler (Eisenia fetida or Eisenia andrei); Lumbricus rubellus (a.k.a. red earthworm or dilong (China)) is another breed of worm that can be used, but it does not adapt as well to the shallow compost bin as does Eisenia fetida. European nightcrawlers (Eisenia hortensis) may also be used. Users refer to European nightcrawlers by a variety of other names, including dendrobaenas, dendras, and Belgian nightcrawlers. African Nightcrawlers (Eudrilus eugeniae) are another set of popular composters. Lumbricus terrestris (a.k.a. Canadian nightcrawlers (US) or common earthworm (UK)) are not recommended, as they burrow deeper than most compost bins can accommodate. Blueworms (Perionyx excavatus) may be used in the tropics. These species commonly are found in organic-rich soils throughout Europe and North America and live in rotting vegetation, compost, and manure piles. They may be an invasive species in some areas. As they are shallow-dwelling and feed on decomposing plant matter in the soil, they adapt easily to living on food or plant waste in the confines of a worm bin.

Bins

The simplest form of vermicomposting involves a bin made from plastic or untreated, non-aromatic wood. Some form of bedding, such as shredded paper or composted animal manure or decaying leaves, fills the bin and mixes with a few handfuls of soil to provide the worms with material through which to burrow. The bedding also requires water to stay moist and allow the worms to breathe. Feed the worms organic food scraps such as vegetables, fruits, tea bags and coffee grounds. Tossing in some egg shells will add calcium for the worms and lower the bin’s acidity level. However, never compost meat, fish, or other fatty, oily foods, otherwise the bin will produce a foul odor. And the best worms for bin vermicomposting are redworms or wigglers.

Windrows

Most commercial farm vermicomposting involves windrows, which are long rows of cow manure. Farmers typically stack the manure in rows 3 feet high and 3 feet wide, with rows often stretching more than 100 feet long. Farmers seed the windrows with worms, making certain to keep the rows moist. Fresh manure added to the ends of the existing rows draws the worms forward to keep the process moving.

Troughs

Cement troughs can also host vermicomposting. Usually the troughs hold only manure, which is aged for at least a week before being placed in the trough. This composting method begins with only a few inches of manure spread across the bottom of the trough. Farmers then add the worms, allowing them to feed on the manure for a few days before adding another layer of manure. More manure layers are added every 10 days until the worm compost reaches the top of the trough.

Pits

Some farmers opt for vermicomposting pits, digging a large hole in which to bury the worms and organic waste material. Of course, before adding the worms and bedding, farmers must line the pit to prevent worms from escaping into the surrounding soil. Canvas feed bags make a good lining, preventing worm passage yet still allowing for suitable water drainage. Farmers fill the lined pit with organic materials, such as straw, grass clippings and manure, and then cover it with soil. After about a week, during which time the pit is watered to maintain its moisture, farmers add worms. The worms immediately burrow into the pit, beginning the vermicomposting procedure.

Properties

Vermicompost has been shown to be richer in many nutrients than compost produced by other composting methods. It has also outperformed a commercial plant medium with nutrients added, but levels of magnesium required adjustment, as did pH. However, in one study it has been found that homemade backyard vermicompost was lower in microbial biomass, soil microbial activity, and yield of a species of ryegrass than municipal compost, It is rich in microbial life which converts nutrients already present in the soil into plant-

43 available forms. Unlike other compost, worm castings also contain worm mucus which helps prevent nutrients from washing away with the first watering and holds moisture better than plain soil. Increases in the total nitrogen content in vermicompost, an increase in available nitrogen and phosphorus, as well as the increased removal of heavy metals from sludge and soil have been reported. The reduction in the bioavailability of heavy metals has been observed in a number of studies.

Advantages & applications

Soil

 Improves soil aeration  Enriches soil with micro-organisms (adding enzymes such as phosphatase and cellulase)  Microbial activity in worm castings is 10 to 20 times higher than in the soil and organic matter that the worm ingests.  Attracts deep-burrowing earthworms already present in the soil  Improves water holding capacity.

Plant growth

 Enhances germination, plant growth, and crop yield  Improves root growth and structure  Enriches soil with micro-organisms (adding plant hormones such as auxins and gibberellic acid)

Economic

 Biowastes conversion reduces waste flow to landfills  Elimination of biowastes from the waste stream reduces contamination of other recyclables collected in a single bin (a common problem in communities practicing single-stream recycling)  Creates low-skill jobs at local level  Low capital investment and relatively simple technologies make vermicomposting practical for less-developed agricultural regions

Environmental

 Helps to close the "metabolic gap" through recycling waste on-site  Large systems often use temperature control and mechanized harvesting, however other equipment is relatively simple and does not wear out quickly  Production reduces greenhouse gas emissions such as methane and nitric oxide (produced in landfills or incinerators when not composted or through methane harvest)

UNIT IV

Biofertilizers

Biofertilizers are the substances which make use of microorganisms to fertile the soil. These fertilizers are not harmful to crops or other plants like the chemical fertilizers. They are actually taken from the animal wastes along with the microbial mixtures. Microorganisms are used to increase the level of nutrients in the plants. They let the plants grow in a healthy environment. They are also environment friendly and do not cause the pollution of any sort. Use of biofertilizers in the soil, makes the plants healthy as well as protect them from getting diseases.

Types of Biofertilizers

Nitrogen Biofertilizers This type of biofertilizers helps the agriculturists to determine the nitrogen level in the soil. Nitrogen is a necessary component which is used for the growth of the plant. Plants need a limited amount of nitrogen for their growth. The type of the crops also determines the level f nitrogen. Some crops need more nitrogen for their growth while some crops need fewer amounts. The type of the soil also determines that which type of biofertilizers is needed for this crop. Fr example, Azotobacteria is used for the non-legume crops; Rhizobium is needed for the legume crops. Similarly, blue green algae are needed to grow rice while Acetobacter is used to grow sugarcane. It means almost all the crops need different types of biofertilizers.

Phosphorusbiofertilizers Phosphorus biofertilizers are used to determine the phosphorus level in the soil. The need of phosphorus for the plant growth is also limited. Phosphorus biofertilizers make the soil get the required amount of phosphorus. It is not necessary that a particular phosphorus biofertilizers is used for a particular type of crop. They can be used for any types of the crops for example; Acetobacter, Rhizobium and other biofertilizers can use phosphorus for any crop type.

Compost Biofertilizers Compost biofertilizers are those which make use of the animal dung to enrich the soil with useful microorganisms and nutrients. To convert the animals waste into a biofertilizers, the microorganisms like abcteria undergo biological processes and help in breaking down the waste. Cellulytic fungal culture and Azetobacter cultures can be used for the compost biofertilizers.

Symbiotic Bacteria Bacteria belonging to the genus Rhizobium are capable of fixing atmospheric N2 in association with leguminous crops. Different species of Rhizobium are used for treating the leguminous crops. Rhizobium sp enter the roots of host plants and form nodules on the root surface. The bacteria depend on the host plant for carbohydrates and water while Rhizobium supplies N to the host. Nitrogen fixed by the Rhizobium is translocated through xylem vessels of the host plant mainly in the form of aspergine and to some extent as glutamine. Rhizobium species suitable for different crops are multiplied on a peat base in laboratories. This inoculum can be applied in three ways and among them, seed treatment is the best.

Free living organisms

The important free living organisms that can fix atmospheric nitrogen are blue green algae (BGA), Azolla, Azotobacter and Rhizospirillum. Among them, BGA and Azolla can survive only in lowland conditions. Small quantity of inoculum of BGA and Azolla can be obtained from laboratories and they can be multiplied in the farmers' fields for subsequent application.

Blue-green Algae (BGA)

Several species of BGA can fix atmospheric N. The most important species are Anabaena and Nostoc. The amount of N fixed by blue-green algae ranges from 15 to 45 kg N/ha.

Large Scale Production of Biofertilizers

Large Population of viable cells of effective strains of specific nitrogen fixing bacteria can be supplied through carrier based powder form of biofetlizer for cultivator use. Biofertilizers production technology includes isolation of bacteria, selection of suitable effective strain, preparation of mother or seed culture, inoculants isolation of bacteria, selection of suitable effective strain, preparation of mother or seed culture, inoculant production, carrier preparation and their mixing, followed by curing, packaging, storage and despatch.

The production of microbial inoculants of Rhizobium, Azotobacter and Azospirillum involves following steps except the both or liquid medium used is different for different organisms. The medium used for respective organism is as follows:

1. Preparation of Mother or Starter Cultures:

Starter cultures of selected strains are obtained after ascertaining their performance in green house and at field levels. The pure culture of efficient strain of nitrogen fixing organism is grown on respective agar medium on slant and maintained in the laboratory. A loopful of inoculum from the slant is transferred in a 250 ml capacity conical flask containing liquid medium. keep the conical flak on rotary shaker for 3-7 days depending whether they are fast growing or slow growing. The content of these flasks usually attain a load of 10 5- 10 6 cells per ml called mother culture or starter culture. This mother cultures are further multiplied in larger flasks.

2. Preparation of Broth Cultures:

Prepare liquid medium for respective organisms. Distribute equal quantity in big conical flasks (1000 ml). Sterilize it in autoclave for half an hour at 15 lbs pressure. After sterilization each flask containing suitable broth is inoculated with the mother culture in 1:5 proportions aseptically. Keep the flaks on rotary shaker for 96-120 hours until the viable

48 count per ml reaches to 10 9 cells. The broths become more thick in consistency. This broth culture with population of 10 9 cells or ml should not be stored more than 24 hours or stored at 4 0C temperature.

3. Preparation of Carrier:

The carrier should have following characters: a) It should have high organic matter above 60%. b) Low soluble salts less than 1%. c) High moisture holding capacity 150 to 200% by weight. d) Provide a nutritive medium for growth of bacteria and prolong their survival in culture as well as on inoculated seed.

Lignite or peat is used as carrier in the preparation of Biofertilizers. The carriers are crushed and powdered to 200 to 300 mesh. Peat or Lignite powder is neutralized by addition of 1% calcium carbonate (CaCO3) and sterilized at 15 lbs pressure for 3-4 hours in autoclave.

4. Preparation of Inoculate i.e. mixing:

The sterilized and neutralized lignite or peat is mixed with high count broth culture in galvanised trays. About 1 part by weight of broth is required to 2 part of dry carrier. Final moisture content varies from 40 to 50% depending upon quality of carriers.

5. Curing or Maturation:

After mixing the broth cultures and lignite or peat powder in 1:2 proportion in the galvanised trays then it is kept for curing at room temp (28°C) for 5 to 10 days. After curing it is sieved to disperse the concentrated pockets of growth and to break the lumps.

6. Filling and Packing:

After curing, sieved powder is filled in polythene bags of 0.5 mm thickness leaving 2/3 space open for aeration of the bacteria. Bag is weighted for desired quantity. Then the bag is packed by sealing. The polythene bag used for filling microbial inoculant should be printed with following information.

49 a) Name of Inoculants b) Direction for use c) Name of crops d) Date of Manufacture. e) Date of expiry.

7. Quality Checking:

Check viable count in the carrier based inoculants by dilution plate method at the time of manufactures. The viable cells count in the carrier based inoculants should be maintained as per ISI specifications.

8. Storage:

The inoculants shall be stored by the manufacture in a cool place away from direct heat preferably at a temp of 15 0C and not exceeding 30 °C ± 2 °C for six months. For long survival of microorganisms, the bag are stored in cold storage at 4 °C temperature.

Azolla:

It is an aquatic heterosporus fern which contains an endophytic cyanobacterium Anabaena azollae in its leaf cavity. It is widely used in Vietnam as biofertilizer for rice. Dr. P.K. Singh at CRRI (Cuttak) has done work on mass cultivation of Azolla and its use in rice and other fields. Mass cultivation of Azolla is done as: firstly, microplots are prepared in which sufficient water is added. Optimum pH (8. 0) and temperature (14- 30ºC) should be maintained. Then microplots are inoculated with fresh Azolla and an insecticide furadon is used to check the attack of insects. After 3 weeks Azolla mat is harvested and fresh Azolla is inoculated in same microplot to repeat the inoculation. Azolla mat is dried to use as green manure. Also Azolla shows tolerance against heavy metals e.g. A. pinnata absorbs heavy metals into cell walls and vacuoles due to specific metal resistant enzymes. It can also be incorporated as green manure in rice field near the polluted areas where heavy metal concentration is present.

Applications

1. It is mostly used in rice fields where water is available for its growth and multiplication. 2. It is supplemented with 8-20 kg phosphate per hectare. 3. It improves the height of rice plants, number of tillers, grains and straw yield. 4. There are 50% higher yields by using Azolla as biofertilizer.

Azospirillum:

It is the associate symbiotic nitrogen fixer, aerobic free living which makes the atmospheric nitrogen available to various crops. This nitrogen-fixing bacterium when applied to the soil undergoes multiplication in billions and fixes atmospheric nitrogen in the soil. Nitrogen fixation in the rhizosphere through the action of nitrogenase enzyme. The Scientists of Indian Agricultural Research Institute, New Delhi have isolates strains of Azospirillum from the roots of grasses, rice, sorghum and maize.

Applications

1. Azospirillum sp. have the ability to fix 20-40 Kgs N/ha

2.It results in average increase in yield of 15-30%.

3. It also results in increased mineral and water uptake.

4. It also promotes root development and vegetative growth.

5. Fortification of the soils occurs with bacterial metabolites and by secreting growth promoters.

It is recommended for Paddy, Millets, Oilseeds, Fruits, Vegetables, Sugarcane, Banana, Coconut, Oil palm, Cotton, Chilly, Lime, Coffee, Tea, Rubber, Flower, Spices, Herbs, Ornaments, trees etc.

Rhizobium biofertilizer

Usually the biofertilizers or strains of Rhizobia are used as seed inoculants during sowing. The seeds are inoculated with Rhizobium culture before sowing. In beginning Rhizobium cultures were based on agar-agar medium which were replaced by soil based ones but now peat and lignite are used. Phosphate is needed for a better efficiency of rhizobial biofertilizer. This biofertilizer is recommended for pulse legumes such as red gram, pea, black gram; oilseed legumes like soybean, groundnut;

Applications

1.Rhizobium can fix 50-200 kgs N/ha in one crop season.

2. It can increase yield up to 10-35%.

3. Due to rhizobial activities, the root hairs and nodules secrete a mucous substance which enhances the soil fertility and growth of the plant.

4. The enzyme nitrogenase will reduce the molecular nitrogen to ammonia which is readily utilized by the plant.

5. By means of seed treatment, the germination of seeds gets stimulated and in turn increase crops yield potential.

Advantages of biofertilizers

1) They help to get high yield of crops by making the soil rich with nutrients and useful microorganisms necessary for the growth of the plants.

2) Biofertilizers have replaced the chemical fertilizers as chemical fertilizers are not beneficial for the plants. They decrease the growth of the plants and make the environment polluted by releasing harmful chemicals.

3) Plant growth can be increased if biofertilizers are used, because they contain natural components which do not harm the plants but do the vice versa.

4) If the soil will be free of chemicals, it will retain its fertility which will be beneficial for the plants as well as the environment, because plants will be protected from getting any diseases and environment will be free of pollutants.

5) Biofertilizers destroy those harmful components from the soil which cause diseases in the plants. Plants can also be protected against drought and other strict conditions by using biofertilizers.

6) Biofertilizers are not costly and even poor farmers can make use of them.

7) They are environment friendly and protect the environment against pollutants.

Importance of Bio-fertilizers:

(i) They increase the yield of plants by 15-35%.

(ii) Bio-fertilizers are effective even under semi-arid conditions,

(iii) Farmers can prepare the inoculum themselves,

(iv) They improve soil texture,

(v) Bio-fertilizers do not allow pathogens to flourish,

(vi) They produce vitamins and growth promoting bio-chemical’s,

(vii) They are non-polluting.

Applications of biofertilizers to crop:

Seedling root dip

This method is applied to the rice crop. A bed of water is spread on the land where the crop has to grow. The seedlings of rice are planted in the water and are kept there for eight to ten hours.

Seed treatment

In this method, the nitrogen and phosphorus fertilizers are mixed together in the water. Then seeds are dipped in this mixture. After the applications of this paste to the seeds, seeds are dried. After they dry out, they have to be sown as soon as possible before they get damaged by harmful microorganisms.

Soil treatment

All the biofertilizers along with the compost fertilizers are mixed together. They are kept for one night. Then the next day this mixture is spread on the soil where seeds have to be sown.

UNIT V

Biological pest control

Biological control is the use of natural enemies to manage populations of pests (such as ladybird beetles, predatory gallmidges, hoverfly larvae against aphids and psyllids) and diseases. This implies that we are dealing with living systems, which are complex and vary from place to place and from time to time.

Biological control is a method of controlling pests such as insects, mites, weeds and plant diseasesusing other organisms.[1] It relies on predation, parasitism, herbivory, or other natural mechanisms, but typically also involves an active human management role. It can be an important component of integrated pest management (IPM) programs.

There are three basic types of biological pest control strategies: importation (sometimes called classical biological control), in which a natural enemy of a pest is introduced in the hope of achieving control; augmentation, in which locally-occurring natural enemies are bred and released to improve control; and conservation, in which measures are taken to increase natural enemies, such as by planting nectar-producing crop plants in the borders of rice fields.

Natural enemies of insect pests, also known as biological control agents, include predators, parasitoids, and pathogens. Biological control agents of plant diseases are most often referred to as antagonists. Biological control agents of weeds include seed predators, herbivores and plant pathogens.

Population dynamics of pests and predators

If populations of natural enemies present in the field are too small to sufficiently control pests, they can be reared in a laboratory or rearing unit. The reared natural enemies are released in the crop to boost field populations and keep pest populations down. There are two approaches to biological control through the release of natural enemies:

 Preventive release of the natural enemies at the beginning of each season. This is used when the natural enemies could not persist from one cropping season to another due to unfavourable climate or the absence of the pest. Populations of the natural enemy then establish and grow during the season.  Releasing natural enemies when pest populations start to cause damage to crops. Pathogens are usually used in that way, because they cannot persist and spread in the crop environment without the presence of a host (‘pest’). They are also often inexpensive to produce.

Biopesticides

Natural enemies that kill or suppress pests or diseases are often fungi or bacteria. They are called antagonists or referred to as microbial insecticides or bio-pesticides. Some commonly used antagonistic microbes are:

Bacteria such as Bacillus thuringiensis (Bt). Bt has been available as a commercial microbial insecticide since the 1960s. Different types of Bt are available for the control of caterpillars and beetles in vegetables and other agricultural crops, and for mosquito and black fly control. The best-known biocontrol agent used in field crops is the bacteria Bacillus thuringiensis var. kurstaki and Bacillus thuringiensis. var. aizawai against diverse lepidopteran pests, and the Bacillus thuringiensis var israeliensis against mosquitoes. Bacillus thuringiensis var kurstaki is produced in local factories in different African countries (e.g. South Africa, Kenya and Mozambique) and can be used against different pests (African armyworm, African bollworm, bean armyworm, beet armyworm, cabbage webworm, cabbage moth, cabbage looper, cotton leafworm, diamondback moth, giant looper, green looper, spiny bollworm, spotted bollworm, pod borers, tomato looper).

Viruses such as NPV (nuclearpolyhedrosis virus), effective for control of several cater-pillar pest species. Every insect species, however, requires a specific NPV-species. An example: The armyworm Spodoptera exigua is a major problem in shallot production in Indonesia. Since experiments showed that SeNPV (NPV specific for S. exigua) provided better control than insecticides, farmers have adopted this control method. Many farmers in West-Sumatra are now producing NPV on-farm.

Fungi that kill insects, such as Beauveria bassiana. Different strains of this fungus are commercially available. For example: strain Bb 147 is used for control of corn borers (Ostrinia nubilalis and O. furnacaiis) in maize, strain GHA is used against whitefly, thrips, aphids and mealybugs in vegetables and ornamentals. Several species of fungi can occur naturally in ecosystems. For example, aphids can be killed by a green or white coloured fungus during humid weather.

Fungi that work against plant-pathogens. Some examples include: Trichoderma sp., widely used in Asia for prevention of soil-borne diseases such as damping-off and root rots in vegetables. Some Trichogramma species against the African bollworm are bred in some laboratories in Africa against lepidopteran pests and aphids. A successful introduction of the neotropical parasitoid Apoanagyrus lopezi against the cassava mealybug (Phenacoccus manihoti) caused a satisfactory reduction of P. manihoti in most farmers’ fields in Africa. This is one of the success stories of classical biocontrol.

Biocontrol of plant diseases by non-pathogenic fungi

Entomopathogenic nematodes against different weevil species (e.g. Steinernema carpocapsae, Heterorhabditis bacteriophora) and to control soil insects like cutworms (Agrotis spp.) in vegetables.

Natural pesticides

Some plants contain components that are toxic to insects. When extracted from the plants and applied on infested crops, these components are called botanical pesticides or botanicals. The use of plant extracts to control pests is not new. Rotenone (Derris sp.), nicotine (tobacco), and pyrethrins (Chrysanthemum sp.) have been used widely both in small- scale subsistence farming as well as in commercial agriculture.

Most botanical pesticides are contact, respiratory, or stomach poisons. Therefore, they are not very selective, but target a broad range of insects. This means that even beneficial organisms can be affected. Yet the toxicity of botanical pesticides is usually not very high and their negative effects on beneficial organisms can be significantly reduced by selective application. Furthermore, botanical pesticides are generally highly bio-degradable, so that they become inactive within hours or a few days. This reduces again the negative impact on beneficial organisms and they are relatively environmentally safe compared to chemical pesticides.

Neem as pesticide

Neem derived from the neem tree (Azadiracta indica) of arid tropical regions, contains several insecticidal compounds. The main active ingredient is azadiractin, which both deters and kills many species of caterpillars, thrips and whitefly. Both seeds and leaves can be used to prepare the neem solution. Neem seeds contain a higher amount of neem oil, but leaves are available all year. A neem solution loses its effectiveness within about 8 hours after preparation, and when exposed to direct sunlight. It is most effective to apply neem in the evening, directly after preparation, under humid conditions or when the plants and insects are damp. There exist different recipes for the preparation of a neem solution.

Neem pesticides play a vital role in pest management and hence have been widely used in agriculture. There has been an evident shift all over the world from synthetic pesticides to non-synthetic ones; this is largely because of the wide spread awareness of the side effects of these synthetic pesticides not only on plants and soil but also on other living organisms. This is a great opportunity for neem pesticides manufacturers to cash in on the growing popularity of natural or herbal pesticides. Neem pesticides are being manufactured and exported to various countries as a lot of research has been conducted to test the safety and efficacy of neem for use as a pesticide (Anis Joseph et al., 2010; Vethanayagam, and Rajendran, 2010). Azadirachtin is the main ingredient used to manufacture bio pesticides. Neem oil and seed extracts are known to possess germicidal and anti-bacterial properties which are useful to protect the plants from different kinds of pests. One of the most important advantages of neem-based pesticides and neem insecticides is that they do not leave any residue on the plants.

Neem pest control is very beneficial for proper crop and pest management. It also helps to nourish and condition the soil, it is environmental friendly, it is nontoxic and it can be used in combination with other pesticide and oil for more effectiveness. Instead of killing the pests, it affects the life cycle of the pests. Anti-feedant properties found in neem compounds helps to protect the plants. Pests generally do not develop a resistance to neem based pesticides. Neem pesticides are generally water soluble and help in the growth of the plants. It acts as pest repellent and pest reproduction controller. The transition from use of synthetic products to natural ones is evident in agricultural industry also. Excessive use of synthetic insecticides has resulted in a series of problems like the development of insect resistance to insecticides, harm to other natural enemies of insects, toxic effects on plants and

59 soil etc. Neem is being used to manufacture what is known as the natural or bio insecticide, that are environmental friendly and do not have any toxic effects on plants and soil. Neem insecticides are used to protect both food as well as cash crops like rice, pulses, cotton, oils seeds, etc. Great for use on all crops, trees, plants, flowers, fruits and vegetable around the home as well as organic and commercial growers. Active ingredient Azadirachtin, found in neem tree, acts as an insect repellent and insect feeding inhibitor, thereby protecting the plants. This ingredient belongs to an organic molecule class called tetranortriterpenoids. It is similar in structure to insect hormones called “ecdysones,” which control the process of metamorphosis as the insects pass from larva to pupa to adult stage. It is interesting to note that neem doesn’t kill insects, but alters their life process. The major parts/extracts of neem seed that are used for making neem insecticides.

According to recent studies conducted on parts of neem, it was found that neem seed extracts contain azadirachtin, which in turn works by inhibiting the development of immature insects. Neem oil or the neem seed oil is extensively used to manufacture insecticides used for different crops. Neem oil enters the system of the pests and obstructs their proper working. Insects do not eat, mate and lay eggs resulting in the breaking of their life cycle. Another interesting function of neem oil pesticides is that they do not harm the beneficial insects. The neem oil insecticides only target the chewing and sucking insects.

Mode of Action

Neem acts as a biopesticide at different levels and in various ways. Primarily it acts as antifeedant ie., when an insect larva is hungry and it wants to feed on the leaf but if the leaf is treated with neem product, because of the presence of azadirachtin, salanin and melandriol there is an antiperistalitic wave in the alimentary canal and this produces something similar to vomiting sensation in the insect. Because of this sensation the insect does not feed on the neem treated surface and ability to swallow is also blocked. Secondly it acts as

Agricultural applications of neem products

Oviposition deterrent ie., by not allowing the female to deposits eggs comes in very handy when the seeds in storage are coated with neem kernel powder and/or neem oil. It also acts as insect growth regulator. It is a very interesting property of neem product and unique in nature, ie., it works on juvenile hormone.

Integrated pest management

Integrated pest management (IPM), which by definition is a pest management system that, in the context of associated environment and population dynamics, utilizes all the appropriate techniques to minimize the pest population at levels below those causing economic injury. Though several parasitoids, predators and pathogens of pests, antagonistic microorganisms were known to be effective for several decades, they were not commercially exploited because of quick knock down effect and easy availability of chemical pesticides instead of biopesticides and IPM. Steadily, there has been growing appreciation about the role of cultural and biological methods in pest control. Cultural and biological methods are the two major components in integrated plant protection.

Cultural methods

Agronomic adjustments, necessary for higher yield, are at the same time are directed at prevention, mass multiplication and spread of pests by modifying the crop microclimate.

Sanitation: It includes removal or destruction of breeding refuges and over wintering of pests. Seed material, farm yard manure etc carrying insect eggs or its stages of development should be carefully screened before their use. Destruction of alternate hosts minimizes pest population build up.

Tillage and inter-cultivation: Ploughing and inter-cultivation brings about unfavourable conditions for multiplication of pests as well as diseases and weeds. Quiescent stages (pupae) of harmful organisms will be exposed to dehydration or to predation by birds and other stages may be mechanically damaged or buried deep in the soil.

Cultivar selection: cultivars with high yield potential and quality without resistance to pests and diseases are the main causes of frequent epidemics and mass multiplication of pests and diseases. A large number of cultivars resistance/tolerance to pest and diseases has been developed to suit different agro-ecosystems. Selection of such cultivars can bring down the losses considerably.

Time of sowing: As weather influences developmental rhythm of plants as well as growth and survival of pests and diseases, serious setback occurs when the weather conditions are such as to bring about coincidence of susceptible growth stages with highest incidence of

61 pests and diseases. Therefore, adjustment in sowing dates is often resorted to as an agronomic strategy to minimize the crop losses. Maize sown late suffers little borer damage, as by then the egg parasite Trichogramma is able to keep down the population of the pest. Rice may suffer less from borer attack if planted early (early June). Early maturing cotton cultivars have become popular in Punjab and Haryana as they escape pink bollworm.

Plant population: Plant population per unit area influence crop microclimate. Dense plant canopy leads to high humidity build up congenial for pest and disease multiplication. Keeping the total plant population constant, inter and intra row plant population can be adjusted to minimize the humidity build up within the plant canopy.

Manures and fertilizers: Excessive nitrogen increases susceptibility of crop to sucking and leaf eating pests. Higher rates of nitrogen application than the recommended rate to hybrids without corresponding increase in phosphorus and potassium is the main factor for heavy pest and disease incidence. Balanced application of NPK helps the crop to tolerate pests and diseases considerably.

Water management: Irrigation can reduce the soil inhabiting pests by suffocation or exposing them to soil surface to be preyed upon by birds. Irrigating potato crop at tuber formation can minimize potato scab. Anthracnose of beans, early blight and charcoal rot of potato can be checked by furrow irrigation than sprinkler irrigation.

Habitat diversification: Many pests prefer feeding on a particular plant or others. This preference may be exploited to reduce the pest load on crop. Crop rotation, intercropping, traps cropping and strip cropping can bring down the pest load considerably.

Behavioural methods Pheromones: Pheromones are ectohormons secreted by an organism, which elicit behavioural responses from other members/sex of its own species. These are extremely selective, nontoxic, highly biodegradable and effective at low application rates. Synthetic sex pheromones are commercially available and are used for surveillance, monitoring and control of many Lepidopterous pests such as spotted bollworm, tobacco caterpillar, potato tuber moth, diamond back moth and leaf folder etc.

Fairomones: These are volatile compounds that evoke behavioural response adaptively favourable to the receiver. Fairomones are released either by the host plant or by the host

62 insects. While former issued by the pest and natural enemies to locate their habitats, the later is used for prey finding and parasitisation/preying. Fairomones from host plant can be effectively used to mass trap pest species as well as for monitoring. Use of fairomonal compounds to increase the efficiency of the predator C. carnea and the egg parasitoid T chilonis had been successfully demonstrated.

Bt Insecticide

Bacillus thuringiensis, often abbreviated as Bt, is a naturally-occurring bacteria that makes pests sick when they eat it. There are two strains commonly used as natural pesticides.Bacillus thuringiensis kurstaki (Btk) gives excellent control of leaf-eating caterpillars such as cabbage worms and tomato hornworms, but has no activity against insects that do not eat treated leaves. After the insects eat the bacteria, their guts rupture and they die. Bt is therefore one of the safest natural pesticides you can use in terms of controlling caterpillar pests of vegetables or fruits without harming beneficial insects.Bacillus thuringiensis israelensis (Bti) can be useful in controlling fungus gnats in greenhouses or houseplants, or for preventing mosquito problems in standing water that cannot be drained or controlled with fish. Bacillus thuringiensis (or Bt) is a Gram-positive, soil-dwelling bacterium, commonly used as a biological pesticide. B. thuringiensis also occurs naturally in the gut of caterpillars of various types of moths and butterflies, as well on leaf surfaces, aquatic environments, animal feces, insect-rich environments, and flour mills and grain- storage facilities.

During sporulation, many Bt strains produce crystal proteins (proteinaceous inclusions), called δ-endotoxins, that have insecticidal action. This has led to their use as insecticides, and more recently to genetically modified crops using Bt genes, such as Bt corn. Many crystal-producing Bt strains, though, do not have insecticidal properties.

Mechanism of insecticidal action

Upon sporulation, B. thuringiensis forms crystals of proteinaceous insecticidal δ- endotoxins (called crystal proteins or Cry proteins), which are encoded by cry genes. In most strains of B. thuringiensis, the cry genes are located on a plasmid (cry is not a chromosomal gene in most strains). Cry toxins have specific activities against insect species of the orders Lepidoptera (moths and butterflies), Diptera (flies and mosquitoes), Coleoptera (beetles), Hymenoptera (wasps, bees, ants and sawflies) and nematodes[. Thus, B. thuringiensis serves as an important reservoir of Cry toxins for production of biological insecticides and insect- resistant genetically modified crops. When insects ingest toxin crystals, their alkaline digestive tracts denature the insoluble crystals, making them soluble and thus amenable to being cut with proteases found in the insect gut, which liberate the toxin from the crystal. The Cry toxin is then inserted into the insect gut cell membrane, paralyzing the digestive tract and forming a pore. The insect stops eating and starves to death; live Bt bacteria may also colonize the insect which can contribute to death. The midgut bacteria of susceptible larvae may be required for B. thuringiensis insecticidal activity.

In 1996 another class of insecticidal proteins in Bt was discovered; the vegetative insecticidal proteins (Vip). Vip proteins do not share sequence homology with Cry proteins, in general do not compete for the same receptors, and some kill different insects than do Cry proteins.

In 2000, a novel functional group of Cry protein, designated parasporin, was discovered from noninsecticidal B. thuringiensis isolates. The proteins of parasporin group are defined as B. thuringiensis and related bacterial parasporal proteins that are not hemolytic, but capable of preferentially killing cancer cells. As of January 2013, parasporins comprise six subfamilies (PS1 to PS6).

Use of spores and proteins in pest control

Spores and crystalline insecticidal proteins produced by B. thuringiensis have been used to control insect pests since the 1920s and are often applied as liquid sprays. They are now used as specific insecticides under trade names such as DiPel and Thuricide. Because of their specificity, these pesticides are regarded as environmentally friendly, with little or no effect on humans, wildlife, pollinators, and most other beneficial insects, and are used in

64 organic farming;[ however, the manuals for these products do contain many environmental and human health warnings, and a 2012 European regulatory peer review of five approved strains found, while data exist to support some claims of low toxicity to humans and the environment, the data are insufficient to justify many of these claims.

New strains of Bt are developed and introduced over time as insects develop resistance to Bt or the desire occurs to force mutations to modify organism characteristics] or to use homologous recombinant genetic engineering to improve crystal size and increase pesticidal activity] or broaden the host range of Bt and obtain more effective formulations. Each new strain is given a unique number and registered with the U.S. EPA[ and allowances may be given for genetic modification depending on "its parental strains, the proposed pesticide use pattern, and the manner and extent to which the organism has been genetically modified formulations of Bt that are approved for organic farming in the US are listed at the website of the Organic Materials Review Institute (OMRI) and several university extension websites offer advice on how to use Bt spore or protein preparations in organic farming.

Use of Bt genes in genetic engineering of plants for pest control

The Belgian company Plant Genetic Systems (now part of Bayer Crop Science) was the first company (in 1985) to develop genetically modified crops (tobacco) with insect tolerance by expressing cry genes from B. thuringiensis; the resulting crops contain delta endotoxin. The Bt tobacco was never commercialized; tobacco plants are used to test genetic modifications since they are easy to manipulate genetically and are not part of the food supply.

Field use of biopesticidial products:

Bt products are used mainly in the control of the following pests: tobacco budworm (H. virescens), grass looper (M. latipes), diamondback moth (P. xylostella), maizeborer (S. frugiperda), cassava hornworm (Erinnyis ello L.; Lep., Sphingidae), potato leafminers (Liriomyza spp.), citrus leafminer (Phyllocnistis citrella Stainton; Lep., Gracillariidae), squash pickleworm (Diaphania spp.) and other lepidopteran defoliators in vegetables. Theacaricide product is also used for mite control in citrus, potato and plantain. Strains of Bt var. israelensis are used for control of mosquito disease vectors. During 1997, over 1000 tonnes of Bt were produced in Cuba, 24% by industrial fermentation and 76% via solid

65 substrate culture. Larvicidal activity of neem oil (Azadirachta indica) is used against mosquitoes. Azadirachta indica (Meliaceae) and its derived products have shown a variety of insecticidal properties. Larvicidal efficacy of an emulsified concentrate of formulated neem oil (neem oil with polyoxyethylene ether, sorbitan dioleate and epichlorohydrin) is commonly used for agricultural and farming purposes. Most caterpillars seen eating leaves can be controlled by Bt when applied at the proper time. In vegetable gardens, armyworms, cabbage worms, diamondback moths, melon worms, corn earworms, green cloverworms, pickleworms, tomato fruitworms, tomato hornworms, grape leafrollers, grapeleaf skeltonizers, salt marsh caterpillars, and various webworms and budworms are candidates for treatment with Bt. Advantages of biopesticides: 1. When used as a component of Integrated Pest Management (IPM) programs, biopesticides can greatly decrease the use of conventional pesticides with high yield. 2. Biopesticides are usually inherently less toxic than conventional pesticides 3. Do not have left over of any harmful residues. 4. Have substantially nullified impact on non-target species. 5. They are cheaper than chemical pesticides. 6. They are effective than chemical pesticides.

Biopesticides are very effective in the agricultural pest control without causing serious harm to ecological chain or worsening environmental pollution. The research and development of practical applications in the field of biopesticides greatly mitigate environmental pollution caused by chemical pesticide residues and promotes sustainable development of agriculture. Since the advent of biopesticides, a large number of products have been released, several of which have already played dominant roles in the market. The development of biopesticides stimulates modernization of agriculture and will, without doubt, gradually replace chemical pesticides. Many biopesticides are ideal substitutes for their traditional chemical counterparts in pollution-free agricultural production, but some of them display certain toxicity; this should be taken into consideration by the researchers in the field. In this paper, we discuss the current development and application of biopesticides from various categories, the problems occurring in the process of their development and proposing the introduction of various constraints. We review various studies and analyze the development trends in biopesticides in agriculture, demand, market and other fields

Control of weeds

Weed control is the botanical component of pest control, which attempts to stop weeds, especially noxious or injurious weeds, from competing with domesticatedplants and livestock. Many strategies have been developed in order to contain these plants.The original strategy was manual removal including ploughing, which can cut the roots of weeds. More recent approaches include herbicides (chemical weed killers) and reducing stocks by burning and/or pulverizing seeds.

A plant is often termed a "weed" when it has one or more of the following characteristics:

 Little or no recognized value (as in medicinal, material, nutritional or energy)  Rapid growth and/or ease of germination  Competitive with crops for space, light, water and nutrients

Weeds compete with productive crops or pasture, ultimately converting productive land into unusable scrub. Weeds can be poisonous, distasteful, produce burrs, thorns or otherwise interfere with the use and management of desirable plants by contaminating harvests or interfering with livestock. Weeds compete with crops for space, nutrients, water and light. Smaller, slower growing seedlings are more susceptible than those that are larger and more vigorous. Onions are one of the most vulnerable, because they are slow to germinate and produce slender, upright stems. By contrast broad beans produce large seedlings and suffer far fewer effects other than during periods of water shortage at the crucial time when the pods are filling out. Transplanted crops raised in sterile soil or potting compost gain a head start over germinating weeds.

Weeds also vary in their competitive abilities and according to conditions and season. Tall-growing vigorous weeds such as fat hen (Chenopodium album) can have the most pronounced effects on adjacent crops, although seedlings of fat hen that appear in late summer produce only small plants. Chickweed (Stellaria media), a low growing plant, can happily co-exist with a tall crop during the summer, but plants that have overwintered will grow rapidly in early spring and may swamp crops such as onions or spring greens.

The presence of weeds does not necessarily mean that they are damaging a crop, especially during the early growth stages when both weeds and crops can grow without

67 interference. However, as growth proceeds they each begin to require greater amounts of water and nutrients. Estimates suggest that weed and crop can co-exist harmoniously for around three weeks before competition becomes significant. One study found that after competition had started, the final yield of onion bulbs was reduced at almost 4% per day.[1]

Perennial weeds with bulbils, such as lesser celandine and oxalis, or with persistent underground stems such as couch grass (Agropyron repens) or creeping buttercup (Ranunculus repens) store reserves of food, and are thus able to grow faster and with more vigour than their annual counterparts. Some perennials such as couch grass exude allelopathic chemicals that inhibit the growth of other nearby plants.

Weeds can also host pests and diseases that can spread to cultivated crops. Charlock and Shepherd's purse may carry clubroot, eelworm can be harboured by chickweed, fat hen and shepherd's purse, while the cucumber mosaic virus, which can devastate the cucurbit family, is carried by a range of different weeds including chickweed and groundsel.

Methods

Weed control plans typically consist of many methods which are divided into biological, chemical, cultural, and physical/mechanical control.[2]

Pesticide-free thermic weed control with a weed burner on a potato field in Dithmarschen.

Physical/mechanical methods

Coverings

In domestic gardens, methods of weed control include covering an area of ground with a material that creates a hostile environment for weed growth, known as a weed mat. Several layers of wet newspaper prevent light from reaching plants beneath, which kills them. Daily saturating the newspaper with water plant decomposition. After several weeks, all germinating weed seeds are dead. In the case of black plastic, the greenhouse effect kills the plants. Although the black plastic sheet is effective at preventing weeds that it covers, it is difficult to achieve complete coverage. Eradicating persistent perennials may require the sheets to be left in place for at least two seasons.

Some plants are said to produce root exudates that suppress herbaceous weeds. Tagetes minuta is claimed to be effective against couch and ground elder,[3] whilst a border of comfrey is also said to act as a barrier against the invasion of some weeds including couch. A 5–10 centimetres (2.0–3.9 in)} layer of wood chipmulch prevents most weeds from sprouting.

Gravel can serve as an inorganic mulch. Irrigation is sometimes used as a weed control measure such as in the case of paddy fields to kill any plant other than the water- tolerant rice crop.

Manual removal

Weeds are removed manually in large parts of India. Many gardeners still remove weeds by manually pulling them out of the ground, making sure to include the roots that would otherwise allow them to resprout. Hoeing off weed leaves and stems as soon as they

69 appear can eventually weaken and kill perennials, although this will require persistence in the case of plants such as bindweed. Nettle infestations can be tackled by cutting back at least three times a year, repeated over a three-year period. Bramble can be dealt with in a similar way.

Tillage

Ploughing includes tilling of soil, intercultural ploughing and summer ploughing. Ploughing uproots weeds, causing them to die. In summer ploughing is done during deep summers. Summer ploughing also helps in killing pests. Mechanical tilling can remove weeds around crop plants at various points in the growing process.

Thermal

Several thermal methods can control weeds. Hot foam (foamstream) causes the cell walls to rupture, killing the plant. Weed burners heat up soil quickly and destroy superficial parts of the plants. Weed seeds are often heat resistant and even react with an increase of growth on dry heat. Since the 19th century soil steam sterilization has been used to clean weeds completely from soil. Several research results confirm the high effectiveness of humid heat against weeds and its seeds. Soil solarization in some circumstances is very effective at eliminating weeds while maintaining grass. Planted grass tends to have a higher heat/humidity tolerance than unwanted weeds. Boiling water applied directly to the crown of weeds can also be an effective small weed killer. Larger weeds require three to four applications before being effective.

Cultural methods

Stale seed bed

Another manual technique is the ‘stale seed bed’, which involves cultivating the soil, then leaving it fallow for a week or so. When the initial weeds sprout, the grower lightly hoes them away before planting the desired crop. However, even a freshly cleared bed is susceptible to airborne seed from elsewhere, as well as seed carried by passing animals on their fur, or from imported manure.

Buried drip irrigation

Buried drip irrigation involves burying drip tape in the subsurface near the planting bed, thereby limiting weeds access to water while also allowing crops to obtain moisture. It is most effective during dry periods.

Crop rotation

Rotating crops with ones that kill weeds by choking them out, such as hemp, Mucuna pruriens, and other crops, can be a very effective method of weed control. It is a way to avoid the use of herbicides, and to gain the benefits of crop rotation.

Biological methods

A biological weed control regiment can consist of biological control agents, bioherbicides, use of grazing animals, and protection of natural predators.[9]

Animal grazing

Companies using goats to control and eradicate leafy spurge, knapweed, and other toxic weeds have sprouted across the American West.

A mechanical weed control device: the diagonal weeder.

Organic weed control involves anything other than applying manufactured chemicals. Typically, a combination of methods are used to achieve satisfactory control.

Sulfur in some circumstances is accepted within British Soil Association standards.

Herbicides

The above described methods of weed control use no or very limited chemical inputs. They are preferred by organic gardeners or organic farmers.

However, weed control can also be achieved by the use of herbicides. Selective herbicides kill certain targets while leaving the desired crop relatively unharmed. Some of these act by interfering with the growth of the weed and are often based on plant hormones. Herbicides are generally classified as follows:

 Contact herbicides destroy only plant tissue that contacts the herbicide. Generally, these are the fastest-acting herbicides. They are ineffective on perennial plants that can re-grow from roots or tubers.  Systemic herbicides are foliar-applied and move through the plant where they destroy a greater amount of tissue. Glyphosate is currently the most used systemic herbicide.[11]  Soil-borne herbicides are applied to the soil and are taken up by the roots of the target plant.  Pre-emergent herbicides are applied to the soil and prevent germination or early growth of weed seeds.

References

1. agritech.tnau.ac.in/org_farm/orgfarm 2. www.fao.org/organicag/oa-home/en 3. ofgorganic.org/ 4. https://www.soilassociation.org/ 5. www.drcsc.org 6. https://en.wikipedia.org/wiki/ 7. https://www.sciencedaily.com/ 8. www.liveayurved.com 9. https://www.nabard.org/ 10. ncof.dacnet.nic.in/ 11. www.organicfacts.net 12. www.conserve-energy-future.com 13. www.newstrackindia.com