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In-situ crop residue decomposition

In-situ crop residue decomposition is the microbial breakdown of standing or chopped stubble in the field after harvest, in place of removal or burning. The practice mineralises residue carbon and nutrients back into the soil and is the principal policy alternative to paddy-stubble burning in North-West India and to cotton, chilli and pulse-stubble disposal elsewhere.

Principle

Crop residues left on the surface decompose slowly under natural microbial action, particularly in tropical soils where lignified rice straw can persist for months. Inoculation with a balanced microbial consortium accelerates the process so that residue mineralises within the field-preparation window for the following crop. The resident microbial community is shifted toward cellulolytic and lignolytic populations that prefer the residue substrate, and a portion of residue carbon stabilises in soil organic matter.

Implementation

The flagship product is the NCOF Waste Decomposer, a consortium of micro-organisms cultured from desi cow dung, authorised by ICAR and sold by the National Centre of Organic and Natural Farming at Rs 20 per 30 g bottle. Farmers multiply the inoculum in 200 L of jaggery solution over 5-7 days and spray the broth onto chopped stubble. For paddy stubble, the spray is followed by light tillage or a one-pass super seeder operation. Wheat seed can be drilled directly through the decomposing residue.

Adoption context

The technique is promoted across the rice-wheat tracts of Punjab, Haryana and western Uttar Pradesh as the substitute for stubble burning, in coordination with custom-hiring centres that rent super seeders and Happy Seeders. NCOF distributes the inoculum through state agriculture departments, KVKs and bio-input shops. The same product is used in chilli, cotton and sugarcane residue management in southern states.

Limitations

Decomposition is slow in dry winter conditions; supplementary irrigation may be required to maintain microbial activity. Heavy stubble loads (above 5 t/ha) require mechanical chopping for adequate inoculum-residue contact. Farmers without access to super seeders or sufficient turnaround time between crops still resort to burning despite legal prohibition.

See also Mulching Organic Residue, Green Manure Dhaincha, Sunn Hemp Green Manure, Sunn Hemp Green Manure 2 and Custom Hiring Machinery.

References

  1. NCOF Waste Decomposer. Vikaspedia agriculture portal.
  2. Waste Decomposer for Organic Farming. Press Information Bureau, Government of India.