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Organic Farming part 1

By DR. Venkatramana Hegde, Hosagadde. Director, Shramajeevi Television Pvt. Ltd. Bengaluru

Introduction

Agriculture has completed one cycle and is turning its phase. Green revolution proved detrimental in 5 decades. Indiscriminate use of pesticides and chemicals polluted the soil, water and the whole eco system. Off late our farmers are looking back. Now we find organic movement everywhere. But most of the farmers are in confusion about both the systems. They question whether total organic is possible and feasible. This article will discuss the necessity, possibility and opportunity for organic farming in detail.

Agriculture started along with human civilization. But it was totally dependent on nature. Use of chemical fertilizers started during 1850 itself in western countries. But in India chemical farming became popular with green revolution started during 1965. High yielding hybrids entered our farms. Chemical fertilizers became inevitable to get higher yield from these hybrids. This paved the way for indiscriminate use of chemical fertilizers. The scientific community supported chemical farming neglecting the possible bad effects of chemicals in long run. Government departments promoted this on priority. It is true that this green revolution produced enough food for the nation. But in due course of time pests and diseases started attacking the crops. Poisonous pesticides entered the scene for crop protection. The hazardous effects of these poisons were quite evident very soon.

Side effects of Green Revolution

Soft top soil started getting hardened due to chemical residues. Ground water was polluted with nitrates, sulfides and other chemical impurities. Balance of nature was lost and pest attack ran out of control. Cabbage and cauliflower need 8 to 10 sprays, cotton needs 13 to 15 sprays and grape consumes 30 to 40 sprays in a season. Then imagine the effect of chemicals. Consumers using these produce and the farmer spraying these pesticides are affected with asthma, allergy, cancer and with many more health problems. A train runs in Punjab full of cancer patients and is locally known as cancer train! We lost rich bio-diversity and balanced nature before we got alerted.

Volume of chemicals used has grown many times from 1965 to 2010. But the increase in production is only 4 times. Even this increase is not just due to chemicals. Increase in cultivated area and irrigation contributed a lot. Off course, only the chemicals are not the culprits. Excess tillage, hybrids targeted only towards high yield, genetically modified crops and varieties, excess irrigation, un-season crop cultivation, un-acclimatized crops and varieties, tendency of easy crop production etc. are also the reasons for the pathetic situation of todays agriculture. Green revolution has become the war against nature. But now we lost the war. Only option with us is to surrender to the nature again.

Bad effects of chemical farming

Crop and varietal diversity is lost due to the popularity of hybrids. Mono-cropping is common everywhere. Quality of food has come down even though the production is more. Use of organic manures decreased with the application of high amount of chemical fertilizers. Hence the humus content of the soil is reduced. This affected the soil structure and hence the aeration. It led to decline in the population of useful aerobic microbes in the soil. Water holding capacity of the soil and percolation of rainwater decreased. Runoff water eroded fertile top soil. Absorption of nutrient was affected due to imbalanced soil pH. Soil microbial activity is quite essential to make the nutrients available for plants. Destruction of soil micro-flora badly affected the nutrient uptake by plants. In chemical farming only 20 to 30% of the nutrients get absorbed. Remaining portion dissolves in the water quickly creating ground water pollution. Chemical residues of the fertilizers accumulated in the soil making it useless for crop production. Excess irrigation created saline and marshy lands. Decrease in organic matter and imbalanced chemical nutrition led to micronutrient deficiency. Due to mass destruction of useful predators and decrease in disease resistance of the plants, crops became easily susceptible for pest and diseases. This increased the application of chemical pesticides again. Even then the productivity is coming down year by year. Chemical residues like nitrates, sulfides and heavy metals have accumulated in soil, water and crops. Ultimately the produce from chemical farming has lost the food value. Chemically adulterated food led to serious health problems of the consumers. Just born baby gets diabetes; hair turns grey by 20 years of age itself. Cancer, the most common deadly disease of today has direct link with pesticide adulteration of the food. Farmer has to purchase hybrid seeds, fertilizers and pesticides from outside. Hence the cost of production has gone up. Profit from farming became illusive. This is the major reason for sudden increase in suicide cases of farmers. Younger generations of farmers are searching opportunity in cities. Government is announcing loan packages instead of attending the real cause for the situation. Even the millionaire has to eat food only and not the money. If the situation continues for long poor people may have to die due to hunger. Sustainable agriculture is the only solution for this complicated situation. Direction is very clear. But reaching the destination is not so easy. However, for the survival of 7.5 billion people on this earth this U turn is inevitable.

Non-chemical farming

Now let us study the non-chemical methods of farming. Again, many new terminologies like organic, natural, zero tillage, sustainable, bio-dynamic, Vedic agriculture etc. have created confusion in the minds of farmers. We have to find alternative ways of nourishing and protecting the crops after avoiding the usage of chemicals. The methods mentioned above follow different ways for this purpose. The basic principles of all these methods are the same. That is using locally available natural inputs, keeping away from chemicals and following the nature. We have compiled all simple ways of non-chemical farming under the title Organic Farming.

Organic farming should improve the health of plant and other living creature. It must enrich and protect bio-diversity. Hence it is a broad based farm management system. The main features of organic farming include optimum use and conservation of locally available natural inputs, increasing soil fertility over a period of time and protecting soil micro-flora etc. Organic farming should produce healthy food to feed and to protect the health of the consumers. Self- dependence for farm inputs will increase the profitability of the farm. If farming becomes a profitable occupation the migration of population to cities will come down. Thus organic farming can give solution for destruction of environment, pollution and social imbalances also.

Many of us still have a doubt whether this organic farming will feed 1.3 billion people of India. To get the answer one has to go through the production statistics of pre green revolution Indian agriculture. District commissioner of Chengalpattu district of Tamil Nadu noted that during 1880-85 the paddy yield was 40 quintals per acre. But now with all chemical fertilizers and pesticides the same farmers are not getting even the half of that yield. It is true that the yield drops while changing from chemical to organic method. But organic farming will increase soil fertility and hence the productivity in long run. Even the pest and disease incidence will come down. It is undoubtedly proved that the systematic organic farming gives sustainable higher yield. Hence the agriculture scientists took U turn in recent years and are supporting organic farming movement.

Characteristics of healthy soil

Soil should be soft enough so that it can be opened by hand easily. It must have sufficient organic matter so that rainwater percolates easily. In scientific terms let the soil pH be between 6.5 and 7.5. Plants can absorb the nutrients only with the help of microbial activity. In very high or low pH soil microbes cannot survive or work efficiently. This affects the availability of nutrients, absorption, seed germination and crop health etc. Other characteristics of good soil are more than 0.5 % organic carbon, 100 kilograms of Nitrogen, 10 kilograms of Phosphorus and 50 kilograms of Potash per acre in available form.

Humus of the soil is the food and shelter for soil microbes. High humus content improves the soil structure. It enables better soil aeration. Thus the plant roots and soil microbes get sufficient oxygen. Soil temperature remains under control. Good volume of rainwater percolates and hence the availability of soil moisture to the plant improves. Water holding capacity of this soil is more. It creates healthy soil microclimate which supports microbial activity. This condition is called as living soil. Ultimately the plant growth and yield improves. Produce from this kind of crop will have better nutrient content and taste.

National guidelines for organic farming

IFOAM is the world federation of organic movement organizations. This was established in 1972 in France. This has member organizations in most of the countries. IFOAM sets the guidelines for organic farming at international level. Indian government formulated national standards for organic production or NSOP in the year 2000. It is mandatory to follow NSOP to get organic certificate. NSOP suggests growing crops and varieties which adopts and comes up well in the locality. These crops must have pest and disease resistance. Organic farmer must protect and enrich crop and varietal diversity. Use the seeds from organically grown crop. If it is not available, use chemically untreated seeds from the conventional crop. There is no objection for the cultivation of hybrids. But genetically modified crops and varieties are not permitted. It is advised to use the manures of plant, animal, microbial and natural origin. Chemical fertilizers, herbicides, hormones, dies and pesticides are strictly not allowed. To be specific, use organic manures such as farm yard manure, poultry manure, cow dung slurry, animal urine, crop residues, green manures etc. produced on organic farm. But human excreta are not permitted. Restricted use of inputs produced outside the organic farm such as blood meal, bone meal, compost, cow dung manure, fish meal, city waste, earthworm compost etc. is allowed after confirming the absence of chemical impurities. Likewise, limited use of calcium and magnesium stone, sulfate of potash, kainite, rock phosphate, wood ash, potassium sulfate, sulfur, boron, iron, manganese, molybdenum and zinc is allowed. Avoid burning of organic matter and destruction of forest. Take necessary measures for the conservation of soil and water. Use machines and implements used in chemical farming only after cleaning.

Organic manures

Let us see the methods of supply of necessary nutrients in organic farming in detail. The nutrient content of various organic manures is like this

Manure

% Nitrogen

% Phosphorus

% Potash

FYM

0.5

0.3

0.4

Compost

1.8 3.2

1.2 1.4

1.2 2.2

Vermi-Compost

0.8 1.5

0.4 0.9

1.0 1.8

Poultry manure

2.0 3.2

1.8 2.0

1.6 1.7

Sheep-goat

2.4

0.88

1.99

Press mud

3.0 3.2

8.0 8.7

0.9 1.0

Biogas slurry

1.3 1.4

1.2 1.4

1.0

 

Production of organic manures is a big business now. The producers of organic inputs must get organic input certificate. Only certified inputs are allowed in organic farming. These manures should have brown or black colour and 15 to 25 % moisture. It should not have any bad smell. These manures must have minimum of 12 % organic carbon, 0.8 % nitrogen, 0.4 % phosphorus and 0.4 % potash. Carbon to nitrogen ratio should be at least 20:1 and pH must be in between 6.5 and 7.5. The upper limit of heavy metals in the organic manures is like this

Heavy metal

Maximum(mg/kg)

Arsenic

10

Chromium

50

Mercury

0.15

Lead

100

Cadmium

5

Copper

300

Nickle

50

Zinc

1000

 

Now let us know the methods of production and usage of various organic manures. Most of the traditional farmers use substandard manures. In western ghat regions manure pit of 8 to 10 feet depth is common. Since it is the open place it wets in rain and dries up under hot sun loosing most of the nutrients. Excess heat accumulates in deeper layers due to lack of aeration. Useful aerobic microbes die and manure becomes a heap of pathogens. Manure decays instead of decomposition. This manure of poor quality is heaped on the farm well before its incorporation in to the soil. Manure dries up and loses nutrients here also. This substandard manure cannot give expected result. Let the manure pit be of 3 feet depth. Protect it from rainwater and direct sun. It is better if the materials are heaped on the ground itself. Adding sheep and poultry manures, wood ash and di-cot herbages with the farm wastes will improve the nutrient content of the manure.

Japanese method of composting

It is popular for quick and good quality manure production. Here the bricks are used to build the tank above the ground. Let the height and width be 3 feet each. Length is according to your convenience. The main point is to keep hole on the walls for aeration. Even we can use wood instead of bricks to save cost. Put fibrous materials at the bottom. Then put a layer of cow dung. Then spread dry leaves and farm waste in a layer. Spread cow dung again. Repeat these layers till the tank is full. Put di-cot herbage and green materials in top layer. At the end cover it with fertile top soil layer. Spread straw or dry leaves on the pit to avoid drying. Manure will decompose fully within 2 to 3 months in this method. Nutrient content of the compost from this Japanese method is better than the sunken pit.

Aerobic method of composting

In this method raw materials are heaped on the hard floor. Shade net is spread on the pendal to avoid direct sun. Let the height and width of the heap be 5 to 6 feet each. Length is according to your convenience. Spread dry leaves, organic farm waste, di-cot herbage, wood ash etc. in layers. Wet each layer with cow dung slurry and water. It is better if neem and caster cakes, rock phosphate, sheep and poultry manures etc. are added. It is desirable to use organic matter decomposition (OMD) microbial mixture for fast and better decomposition. This contains nitrogen fixing and phosphorus solubilizing bacteria, mycorrhiza for potash, Pleurotus fungus for fiber degradation, Trichoderma for pathogen control. If this OMD microbial mixture is not available, use the compost which was prepared using such mixture. Or at least put a layer of fertile soil. Keep the heap moist by sprinkling water. Spreading cow dung slurry and Panchagavya will give better result. Insert bamboo or perforated PVC pipe in the heap for better aeration. Compost will be ready for use within 1 month itself in this aerobic method. Even the coconut coir pith becomes good compost if OMD mixture is used. But it takes 3-month time for decomposition. Most of the commercial organic manure producers follow this method. Use of 2 tons of this compost gives better result than 10 tons of conventional manures. We can get still better compost by feeding this to earthworms.

Earthworm compost

Vermi-compost is very popular among organic farmers. There are 2 types of earth worms. One type of worm burrows deep in to the soil and the other one lives in top soil. Top soil earthworms feed 10 % of soil and 90 % of organic matter. It eats equal to its body weight and puts out every day. Earthworms add 30 to 40 kilograms of nitrogen per acre per year. Vermi compost is rich in growth regulators and hormones. Hence it is the complete manure. Vermi compost has egg cases too. If the farm has sufficient moisture content and organic matter earthworms develop from the eggs and produce compost there itself. We need not apply vermi compost again.

We may give vermi compost to all crops. Apply 1 ton of vermi compost for field crops at the time of sowing or in the row later. Adding half ton of vermi compost to seed beds will improve the growth and health of the seedling. Then give half kilogram of vermi compost to each plant at the time of re-planting and half kilogram after 45 days. Apply 5 to 10 kilograms of vermi compost per year to bigger trees. Pour water to the vermi tanks and collect the drained water as vermi wash. This is an excellent mixture of major and micro nutrients, growth regulators and hormones. Even it is a good repellent of pests and diseases. We can get excellent crop by spraying vermi wash.

Let us study the method of production of vermi compost now. Bigger earth worms from Africa are in use for this purpose. Vermi compost production capacity of these worms is much higher than our indigenous worms. It grows up to 5 to 6 inches and lives up to 2 years. It prefers 25 to 30˚ centigrade temperature and 40 to 45 % moisture. We may feed these worms with dry leaves, crop residues, sugar cane waste etc. But avoid flowers and tobacco plant. Spray water and mix cow dung to the raw material and heap under shade for 3 to 4 weeks. Then this partially decomposed material is fed to the earthworms. If the fresh farm waste is given directly, heat generated during decomposition may kill the worms.

It is better to provide roof for vermi compost tanks to avoid rain and direct sun. Normally tanks are built with stone or cement for this purpose. However, many farmers follow heap method under shade. Even portable vermi tanks of thick plastic are also seen. It is advised to limit the width of the tanks to 3 to 4 feet and height to 2 to 3 feet. Length is according to your convenience. Provide a hole at the bottom of the tank to drain excess water. Put a layer of course material like coconut husk at the bottom of the tank. This is necessary to drain excess water and vermi wash. Then put a layer of organic waste for half feet height. Spread fresh cow dung or slurry on it. Put another layer of organic material. Repeat these layers till the tank is full. Then spread earthworms on the top at the rate of 25 worms per square feet. If worms are not available spread fresh -moist vermi compost. The eggs in this compost will hatch to produce tiny worms. But it will take more time to produce compost. Spray water to maintain 40 to 45 % moisture. Compost will be ready within 2 to 3 months depending on the raw material used. The worms go deep in to the tank if water is not given for 3 to 4 days. Then collect the vermi compost from the top. Sieve this compost after drying excess moisture. Continue the production of vermi compost by spreading the raw material again in to the tank.

Birds, ants, rats and mice are the enemies of the earthworms. It is better to put stone slab or cement concrete to the floor of the vermi compost shed. Water channel around the vermi tank or spreading wood ash will avoid ants. But do not use any pesticides for the purpose. Production of vermi compost is a rural commercial subsidiary activity now. This can generate an attractive income for small farmers and landless people. Many big dairies sell vermi compost instead of dung to generate additional income.

Panchagavya

Panchagavya for agriculture use is also becoming popular now. This is a Vedic concept. We are giving a representative composition of Panchagavya out of many combinations in use. Take a plastic barrel or cement tank and put 3 liters of cow urine, 2 liters of cooled boiled cow milk, 2 liters of curd, 10 bananas, 3 liters of tender coconut water and 1 kilogram of brown Jaggary or molasses dissolved in 3 liters of water. In another barrel mix 5 kilograms of fresh cow dung and 1 liter of cow ghee. Mix the content of these barrels after keeping them separately for 3 days. Then keep it for 7 days. Keep on stirring the mixture once in a day with a wooden stick. Filter this mixture through a net and keep the barrel covered with a cloth to the open top. This Panchagavya may be used up to 15 to 20 days. This is a rich mixture of micronutrients, hormones, plant growth regulators and useful microorganisms. This is a good repellent of pests and diseases also. Panchagavya may be sprayed to the crops or drenched to the base of the plant. It may be spread at the time of compost production. Excellent result is recorded everywhere with the use of Panchagavya.

Alternate organic ways of nutrition

Let us know one more method of supplying nutrients. Mix 10 kilograms of fresh cow dung, 10 liters of cow urine, 1 kilogram of Jaggary (thick molasses) and 100 liters of water in a tank or barrel. Use this mixture on next day with irrigation water at the rate of 500 liters per acre. For spraying, mix 10 kilograms of cow dung, 10 liters of cow urine, 1 kilogram of Jaggary and

10 liters of water in a tank. Filter this mixture on next day and spray to the crop at the rate of 100 ml per liter of water. Spraying this extract 2 to 3 times for any crop will give good result.

We find bio-digesters in many farms in recent years. Locally available herbages are digested in a tank. Di-cot plants and plants well known for pest and disease control are selected on priority. Some farmers put neem cake, sheep and poultry manure, vermi compost etc. in bags and immerse it in the same tank. Extract collected in the tank or the digester is filtered and given to the crop with irrigation water. Many farmers spray this extract directly to the crop. According to the farmers experience this extract from the bio digester improves crop health and growth.

We find farm houses and cattle shed at a height just next to the garden in western ghat region. Many farmers stopped producing farm yard manure due to labor shortage. Transporting the manure needs lot of manpower and leads to nutrient loss also. Hence these farmers flow biogas slurry directly to the garden through pipe line. Slurry is put to the base of each tree with the help of hose pipe. Slurry is collected in a tank and diluted with additional water. Leaves, straws etc. are cleaned to avoid clogging of pipe line. This mixture flows to the garden by gravity. Farmers without this benefit of slope use slurry pump. Slurry is transported in a tanker to the garden if the distance is more. Organic waste available on the farm is put around the tree base and slurry is poured on it twice a year. This may be called as in situ manure production. Here the wastage of nutrients is very minimal. Earthworms become active and produce vermi compost. This method gives very good result if the moisture is maintained throughout the year in the garden. This method is termed as slurrygation.

Green manuring

Green manuring is one more effective method of supplying nutrients. Leguminous plants are grown on the farm or outside and the herbage is mixed in the soil. This enriches the humus and nutrient content of the soil. It improves the soil structure also. Sun hemp, diancha, Sesbenia etc. are the common green manuring species grown on the farm. These plants are cut and ploughed in to the soil just before flowering. Adding green manures 2 to 3 weeks before planting of the main crop will give good result. Sun hemp is grown between rows of sugarcane, banana, mulberry etc. It is incorporated in to the soil after 4 weeks. Black gram, green gram and cow pea are also in use as green manure crops. Sun hemp, horse gram etc. are grown in open spaces of mango and other plantations. This helps even for weed control. Root knots of these leguminous plants store nitrogen. Subabul, Gliricidia, Sesbenia etc. are grown outside the farm or along the fence. Herbage is cut and used as green manure. Green manuring once in 2 years also brings excellent crop improvement.

Non edible oil cakes are the rich source of plant nutrients. Neem cake is not only useful for nutrient supply but also for pest and disease control. Caster and Pongamia cakes are the other cakes in use. Water fern Azolla is becoming popular in recent years as a green manure and cattle feed. Blue-green algae called Anabaena present in the folds of leaves fixes atmospheric nitrogen. Azolla provides 25 kilograms of nitrogen per acre in a season. It can grow and cover the whole water surface of paddy field in 15 days. It is puddled in to the soil as green manure one week before transplanting the paddy seedlings. Tank silt is lifted after the water dries up in summer and spread in the field. This is a popular practice in plains. Adding tank silt can give good crop for 2 to 3 years. Wood ash is also a good source of plant nutrients.

Bio-fertilizers

Bio fertilizer is another important source of nutrients. This is a mixture of microorganisms supplying plant nutrients by fixation or solublisation. Rhizobium is the most popular bio-fertilizer. This bacterium lives in the root knots of leguminous plant and fixes atmospheric nitrogen. Rhizobium plays an important role in di-cot grams like red gram, black gram, green gram, Bengal gram etc. and in oil seeds like ground nut and soya bean. Rhizobium fixes 20 to 40 kilograms of nitrogen per acre per season. Thus it meets 80 to 90 % of nitrogen requirement of the crop naturally. Rhizobium treatment in these leguminous crops will bring 15 to 30 % improvement in yield. Apart from that sizable amount of nitrogen remains in the soil and is utilized by next crop. However, the effectiveness of bio-fertilizer largely depends on soil type, climatic condition, method of pest and disease management, fertilizer use, sub-species of the microorganism used and method of application etc.

Cost of bio-fertilizer is very less. For seed treatment it will be INR 25 per acre. Rhizobium is grown in the laboratory, mixed with charcoal powder and supplied to the farmers. Prepare Jaggary solution. Smear this sticky solution on the seed. Spread the bio-fertilizer on it and mix thoroughly. It sticks well on the seeds due to Jaggary solution. Dry the seeds under shade and use it for sowing as early as possible. Seed treatment of the bio-fertilizer is the easiest and effective method.

There are few more bio-fertilizers in use. Azotobacter is the free living nitrogen fixing bacteria around the plant roots. It is beneficial for vegetables and all other crop plants. Use of this broad spectrum bio-fertilizer can bring up to 20 % yield improvement in paddy, wheat, sorghum, maize, sugar cane, cotton, potato, sunflower and other crops. Azotobacter can fix 10 kilograms of atmospheric nitrogen per acre in a season. Apart from this it helps for better seed germination, more root proliferation, early flowering and maturity also. Azotobacter is used by seed treatment, dipping plant roots, spreading to the soil or by mixing while preparing compost. Azotobacter synthesis some plant growth substances like vitamin B, IAA, gibberellins, cytokinins etc. and stores in the soil, which improve the crop growth. Azotobacter produces some antibiotic substances which hinder the development of pathogenic fungi, bacteria and viruses. It improves the availability of phosphorus also.

Azospirillum is another bacterium in use as bio-fertilizer. This is also a free living nitrogen fixing microorganism. Application is similar to Azotobacter. Azospirillum gives good result in sorghum, minor millets, maize, sugarcane and wheat. Apart from this nitrogen fixing bacteria VA mycorrhiza is used to improve the availability of phosphorus, zinc, copper and sulfur. This is a hair like primitive plant which lives in association with plant roots. It gets food from the plant and helps the plant to absorb water and nutrients. The main constraint of VAM is that it cannot be cultured separately. It needs to be maintained with host plant itself. Roots of these host plant is applied to add mycorrhiza to the field.

Phosphorus gets fixed and becomes unavailable to the plant at very high or low pH levels. To make it available phosphorus solubilizing bacteria or PSB is in use. This can release 12 kilograms of phosphorus per acre in a season. PSB is effective for paddy, minor millet, oil seeds, di-cot grams and vegetables. This bacterium may be used for seed treatment, dipping roots or spreading to the soil directly. 200 grams of PSB is necessary for seed treatment for medium sized seeds like ground nut or wheat. For small seeds 100 grams of PSB is enough. For root dipping method mix 1 kilogram of PSB bio-fertilizer in 10 to 15 liters of water. Dip the roots of the seedlings in the mixture for 5 minutes and plant as early as possible. This dipping method is useful for transplanted crops like vegetables and paddy. For spreading directly to the field mix 3 to 5 kilograms of PSB with 50 kilograms of farm yard manure and apply.

Keep any bio-fertilizer in cool place without direct sunlight. Avoid contact with fertilizer or any chemical. Do not use any bio-fertilizer after expiry date. In Rhizobium there are separate strains for different crops. Using only the specified strain will give good result.

Cultural practices

Cover crops and mulching are becoming popular again. You find creepers covering the whole area of many gardens. Few farms spread green herbages to cover the soil surface. In banana plantations the wastage of the same crop is spread. Growing cover crops in rubber plantation is a popular practice. It is useful for weed control, soil and moisture conservation. Mulching increases soil microbial activity and hence the soil becomes living soil. Decomposition of mulch adds organic matter to the soil. Percolation of rainwater improves. Selecting leguminous species for the purpose of cover crop is still better.

Agro forestry is the important component of organic farming. Growing useful plants and trees as live fence and in available free spaces provide organic matter for manuring, wood for agriculture use and firewood. Green manure and fodder species are the better choice for agro forestry. It provides food and shelter for honey bees and birds. Hence it enriches the bio-diversity of the farm. Live fence is useful as wind breaker in banana plantation. Thus agro forestry is the integral part of organic farming.

Inter cropping and mixed cropping are also one of the important features of organic farming. Generally leguminous crops are intercropped with mono-cot crops. Sorghum-red gram-cow pea, sugarcane soya bean, maize red gram, banana cowpea etc. is the popular combinations. Planning these combinations depends on crop duration, growth nature, height, spreading of roots etc. Di-cot crops improve the soil fertility apart from crop yield. This improves the growth and yield of mono-cot crops. Mono-cropping leads to deficiency of micro nutrients. Multiple cropping systems are helpful even for weed, pest and disease management. Likewise crop rotation is useful in organic farming. Paddy crop in Kharif season and ground nut, black gram, green gram, cowpea etc. in Raby season is a popular practice in traditional paddy area. Leguminous crop in the crop cycle improves the soil fertility and the next mono-cot crop gets the benefit. Crop rotation helps to break pest and disease build up also. Deep rooted crops in the crop cycle bring nutrients from deeper layer to the top soil.

Deep and excess ploughing is not advisable in organic farming. Unnecessary ploughing disturbs the soil structure and leads to soil erosion. Tilling is inevitable in annual crops. But in plantations avoid inter cultivation and cut off the weed and use it for mulching. This helps for weed control and conservation of moisture. It creates micro climate and adds humus to the soil. Excess irrigation is not good. It leads to the depletion of nutrients apart from the wastage of water. Salts in the deeper layer of alkaline soil come to upper layer due to over irrigation and makes the soil saline. Micro or sprinkler irrigation is better in organic farming to maintain humid micro climate and for better decomposition of organic matter.

Weed is not the enemy of crops. Some weeds bring nutrients from deeper layer of soil to the upper layer. Cutting the weed before flowering is the better practice. We may use small rotary tiller for inter-cultivation. Some weeds like touch me not and cassia tora belong to legume group which have nitrogen storage in root knots to enrich soil fertility.

Dear readers, till now we have studied the necessity of organic farming, principles, national policy, alternative methods of nutrient supply etc. in detail. The second part of this article will cover pest and disease management in organic farming, organic certification, animal husbandry and bee keeping in organic method etc. Let us meet again in the next part of this article.