Green manures pk mani


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Green manures

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Green manures pk mani

  1. 1. Green manures Dr. P. K. Mani Bidhan Chandra Krishi Viswavidyalaya E-mail: Website:
  2. 2. Green manures Green manure refers to “a plant material incorporated with the soil while green or soon after maturity for improving the soil to supply nutrients, particularly N, to a standing crop” (Soil Science Society of America, 1978) Green manuring is a practice of ploughing or burying the undecomposed green plant tissues into the soil for improving structure and fertility of the soil.
  3. 3. Green-manuring can be done in 2 ways depending on the situation. (i) Green-manuring in situ: this is the growing and burying of a green manure crop in the same field as the one to be manured. (2) Green-leaf manuring: GLM refers to turning into the soil green leaves and twigs collected from shrubs and trees grown on bundhs, wastelands or nearby forest areas
  4. 4. Sesbania rostrata
  5. 5. Crops suitable for green leaf manuring Glyricidia Pongamia Leucaena leucenalis Legumes: Glyricida ( Glyricidia maculata), Wild dhaincha (Sesbania speciosa), Karanja (Pongamia pinnata), Wild indigo (Tephrosia purpurea,
  6. 6. Characteristics of green manure crops Profuse leaves and rapid growth in early life Abundance and succulent tops Capable of making good stand on poor and exhausted soils Preferable legume with good nodular growth habit
  7. 7. Advantages of Green Manuring  It add organic matter to the soil and stimulates microbial activity  Improves soil structure  Acts as a cover crop ,facilitates penetration of rain water, decreasing erosion and run off  Nutrient taken up from the deeper layers by green manure crops and return the nutrient to the top soil  Legume crop also add nitrogen
  8. 8. Limitations Rainfed condition : Green manure crops will not decompose readily due to lack of water  GM is feasible for assured irrigation facility  Cost of growing GM crop is more than cost of Fertilizer  For higher Cropping intensity land is unavailable for GM cultivation Disease, insects and nematodes may come up due to improper decomposition
  9. 9. Methods of Green Manuring in situ Summer sown catch crop Land Preparation: 3-4 ploughings followed by 1 laddering Sowing : May-June , immediately after 1st monsoon rains. Dhaincha and Sunhemp are generally sown in Aman for green manuring. Paddy field Method of sowing: broadcasting Seed Rate: Dhaincha : 40-45 kg/ha Sunhemp : 40-50 kg/ha Moong : 25-30 kg/ha Manuring: Superphosphate@150 kg/ha applied at last ploughing(increases the P availability for succeeding Aman rice Burial of GM crops: at the flowering stage; (Dhaincha 6-8 wks old, Sunhemp: 4-5 wks old). During decomposition there must be adequate moisture in the field and allowed to decompose for 3-4 weeks
  10. 10. DHAINCHA (Sesbania aculeata)
  11. 11. Sesbania Seed
  12. 12. Cultivation of Chaiti Moong at AB Farm, BCKV
  13. 13. green manure -cum-fibre crop SUNNHEMP (Crotalaria juncea
  14. 14. Sunhemp Seed Sunn Hemp provides as much as 20 tons per acre of green tonnage with a maximum of 150 units of Nitrogen fixation per acre in as little as 90 days.
  15. 15. Inter row sown crop: The seed sown between two rows; Dhaincha (paddy) Sunhemp, cowpea (Cotton , Maize) Green Leaf Manuring: The suitable perennial shrubs and trees are grown on border of paddy fields or bounds or on vacant spaces for the purpose of utilizing their leaves and twigs as green manure. These are incorporated in the soil at the time of puddling of paddy field Brown Manuring
  16. 16. Brown manuring is a technique to grow Sesbania in standing rice crop and kill them with the help of herbicide for manuring. After killing the color of the sesbania residue become brown so it called brown manuring. Brown manuring practice introduced where Sesbania crop @ 20 kg/ha is broadcasted three days after rice sowing and allowed to grow for 30 days and was dried by spraying 2,4-D ethyle easter which supplied upto 35 kg/ha N, dry matter, control of broad leaf weeds, higher yield by 4-5 q/ha due to addition of organic matter in low fertile soils
  17. 17. Crops suitable for green leaf manuring Karanja (Pongamia glabra) Glyricidia Glyricida ( Glyricidia maculata), Neem (Azadiracta indica) Karanja (Pongamia glabra) Wild indigo (Tephrosia purpurea) Subabool Leucaena leucenalis 24
  18. 18. Glyricidia maculata
  19. 19. Root knot nematode Rhizobium nodule
  20. 20. Mineralization, immobilization, and C:N ratio High C:N ratio material added to soil Nitrogen availability Available soil N is immobilized C02 evolution increases Available N increases through N mineralization Time Nitrogen immobilization and mineralization after material with a high C:N ratio is added to soil.
  21. 21. General purpose decay organisms vs. nitrifiers Residues with high C/N ratio added Residues with low C/N ratio remain Nitrate depression period
  22. 22. The C/N ratio of organic residues added to soil will depend upon the maturity of the plants turned under. The older the plants, the wider will be the C/N ratio and the longer will be period of nitrate suppression. Obviously, leguminous tissue will have a distinct advantage over nonlegumes since the former will promote a more rapid organic turnover in soils
  23. 23. Sesbania rostrata - a stem nodulating green manure
  24. 24. Azorhizobium caulinodans on Sesbania
  25. 25. Phosphocompost
  26. 26. Principles of phospho-composting Phospho-composting is based on sound scientific principles. During the decomposition of organic materials, intense microbial activity occurs. As a result a large number of organic acids and humic substances are produced. Some of the most commonly produced organic acids are: citric, malic, fumaric, succinic, pyruvic, tartaric, oxaloacetic, 2-ketogluconic, lacticoxalic, propionic and butyric (Stevenson, 1967).
  27. 27. Phospho-compost is a compost prepared by addition of low grade rock phosphate and phosphate solubilizing micro-organisms with organic wastes. Rock phosphate, as a cheaper source of P In the process of decomposition many organic acids are liberated. Due to this acidic condition, P from rock phosphate gets solubilized and compost becomes enriched.
  28. 28. PHOSPHOCOMPOST Ingredients: Oragnic wastes Raw Cow dung Compost Soil Total Rockphosphate Pyrite Urea Cultures : 80 kg (60 kg dry+20 kg green) : 10 kg : 5 kg : 5 kg : 100 kg : 20 kg : 10 kg : 2.2 kg : 0.05 kg Dry organic wastes: Straw, husk, waste from cattle shed, stems of mustard , sesame, etc. Green : Waterhyacinth, legumes, weeds, vegetable clippngs, leaves, grasses
  29. 29. Nitrogen required for Stimulating the microbial activity Pyrites are added due to acidification of the mixture during composting to prevent volatilization loss of N and also to increase P solubilization Phosphate Rocks Cellulose decomposer: Aspergillus awamori (fungi) (500g mycelial mat / ton of materials) P-solubilizers: Bacillus megatherium. Bacillus polymyxa, Pseudomonas striata (50 ml/kg of materials having 108 viable cell)
  30. 30. Divide entire Organic and inorganic component in 10 equal parts Preparation of 1st Layer I part Phosphate Rock(2kg) and I part Pyrite(1kg) Urea (200g) + microbial Cultures(5g) make it a slurry 9-12// I part cowdung (1 kg) + compost (0.5 kg) + Soil (0.5kg) make slurry in water Covered with Polythene sheet g dun cow l+ s oi with d mu f er o Lay Dry organic wastes 4th Layer 3rd Layer 2nd Layer 1st Layer Keep it for 3 months , yielding 65-70 kg PhosphoCompost
  31. 31. Method of Phosphocompost Making •Select a suitable upland place, sufficient sunlight, free from water stagnation •Prepare a base with either brick floor or spread the polythene sheet on the floor •Collect all the ingredients (organic and inorganic) as per proper ratio for the desired pdn level. •Divide the entire ingredients into 10 parts •Step-1:Take one bucket and add Raw Cow dung- 1kg, Compost- 0.5 kg, Soil -0. 5 kg and small water, stir the material and make a slurry. •Step-2: Take 2nd bucket and add urea-200g, cultures-5g and add water small, make another slurry •Step-3:Spread dry wastes followed by green wastes and make it 12″ height •Step-4:Now add slurry from 1st bucket (cow dung etc slurry), next add slurry from 2nd bucket and spread evenly. •Step-5: Now spread 2 kg Rock phosphate and1 kg Pyrite •Repeat the process Step-1 to step 5 and repeat until 10 layers is formed. • covered the top and side portion of the heap with Layer of mud (soil+ cowdung) and subsequently cover with poly thene sheet to prevent water •1st turnings after 4 weeks and 2nd turnings after 8 weeks • Water is added to the heap so that moisture remains between 60 to 70%. •Add water at each turning to maintain the moisture content between 60 and 70%. •The compost becomes ready for field application within 90-100 days period.
  32. 32. Nutrient composition of phosphocompost Manure Phosphocompost Total N (%) Total P (%) S C: N ratio 1.2-1.4 2.00-3.50 1.5-2.0 17.018.0 Phospho-compost application increased the PUE of greengram (12.90%) and wheat (20.48%) over SSP (Mishra et al. 1982).
  33. 33. WILD INDIGO (Tephrosia purpurea)
  34. 34. Azolla video