Organic Farming

Organic Farming

• It means no use of hazardous chemicals. Government rule says atleast 3 years, a farmer must grow only then, Organic farming can be granted.
• Effect of Inorganic Fertilizers and other agro-chemicals on Soil and Plants
  1. It results in nutrient loss and increases soil acidity with nitrification.
  2. Emission of Ammonia, Methane, Nitrous oxide and elemental nitrogen from soil as a result of denitrification.
  3. Depletion of secondary and micro nutrients especially Sulphur and Zinc.
  4. Nitrogen Fertilizers without the use of organic manures, there is always the human depletion and fall in the crop production.
  5. Nitrate pollution of drinking water in Punjab due to leaching.
• Advantages of Organic Manures
  1. It provides all the nutrients required by the plants but in limited quantities.
  2. It helps in maintaining the C: N ratio in the soil and also increases the fertility and productivity of soil.
  3. It improves structure and texture of the soils.
  4. It increases the water holding capacity of the soil.
  5. Nutrients present in the lower depths are made available to the plants.
  6. It minimizes the evaporation and loss of moisture from the soil.
• Major organic sources and transformations
  1. Carbon present in the soil is in the form of organic matter. The organic materials includes Farm yard manure (FYM), animal wastes, crop residues, urban organic wastes, green manures, biogas slurry, vermicompost etc.
  2. For all organic matter, atmospheric CO2 serve as the main source of Carbon which is converted to Carbon by plants and algae (aquatic habitat).
  3. Calvin cycle leads to Carbon fixation. It involves reduction of CO2 by hydrogen donor NADPH and then synthesis of carbohydrate from reduced carbon.
  4. A great variety of microorganisms live in soil which includes bacteria > actinomycetes > fungi > algae > protozoa.
  5. Organic manures include bone meal, tree leaves, dry; green manures (cowpea, mothbean, green gram etc); edible oilcakes (coconut, groundnut, sesame etc.) and non edible oilcakes (cotton, karanj, neem, safflower etc.)
• Green Manuring
  1. It is the practice of ploughing or turning into the soil undecomposed green plant tissues for improving physical structure as well as soil fertility.
  2. It includes Sesbania aculeate, S. rostrata, Crotalaria juncea, Tephrosia perpurea, Green gram, Black gram and Cow pea.
  3. Advantages of Green manure
     1. It improves both physical and chemical properties of soil.
     2. It provides nutrients and energy to microbes as they decompose rapidly and easy to retain the organic matter.
     3. It acts as mulch and prevent soil erosion. It controls the leaching of nutrients in light soils.
     4. It can control weeds. They can minimize the use of nitrogenous fertilizers.
• Vermicomposting
  1. It is the culturing of Earthworms. It is applied for composting non toxic solids and liquid wastes from dairies, cities, sugar factories, pulp and paper mills, tanneries, fermentation industries and food processing units.
  2. Benefits of Earthworms
     1. It improves soil fertility and recycling of city and rural waste, sewage waste and sludge and industrial wastes.
     2. It is used in Unani system of medicine for treatment of some diseases.
     3. It improves the physical condition of soil and corrects deficiencies in plants.
• Biofertilizers consist of Nitrogen fixers (Rhizobium, Azetobactor, Blue green Algae, Azolla), Phosphate solubilizing bacteria (PSB) and fungi (Mycorrhiza).
• Biofumigation: Green manures can be used to interrupt pest and disease cycles similarly as crop rotation: It is Biofumigation. It can be used to control root knot nematodes and root rot fungal pathogens, reducing the need to use toxic chemicals for soil fumigation.
• Govt has launched National Project on Organic Farming, 2004.