Sustainable management of crop residues in India

Indian agriculture produces about 650 million tonnes of crop residues annually. The residues are used for animal feed, soil mulch and manure, thatching for rural homes and fuel for domestic and industrial use and thus are of tremendous value to farmers. However, approximately 90–140 Mt of the residuesare burned on-farm primarily to clear the field from straw and stubble of the preceding crop for sowing of the succeeding crop. Recently, the problem of on-farm burning of residues has intensified due to unavailability of labour, high cost of removing the residues and use of combines without straw spreading mechanism. The problem is severe in the mechanized rice-wheat system of the northwest India. Burning of crop residues leads to release of soot particles and smoke causing human health problems; emission of greenhouse gases such as carbon dioxide, methane and nitrous oxide causing global warming; loss of plant nutrients such as N, P, K and S; and adverse impacts on soil properties. The paper discusses the amounts of crop residues available in the country and extent of on-farm burning, and identifies the competing uses of crop residues, and the research needs. The residues can be gainfully utilized for livestock feed, composting, power generation, production of biofuel, mushroom cultivation and extraction of bioactive compounds using secondary agriculture technologies. Conservation agriculture (CA), can be effectively practiced if need-based region-specific, crop residue management plans are developed taking into consideration generation, demand, quality, feasibility and economics of residue management.