Crop residue management in rice–wheat cropping system for resource conservation and environmental protection in north-western India

Residue management is the emerging challenge for sustainable growth of Indian agriculture and environmental protection mainly in Indo-Gangetic Plains (IGP). Out of 620 MT crop residues produced annually in the country, 234 MT is surplus and 30% of it is contributed by rice and wheat. Approximately 16% of total crop residue being burnt, 62% is contributed by rice and wheat. At present, we do not have any viable and systematic approach to deal with crop residues or adoption rate is poor. Therefore, the farmers in majority burn rice residues in the field, which leads to huge nutrient loss besides deteriorating environment and human health. Major forces enforcing residue burning are combinde harvesting, lack of traditional use of crop residues, intensive cropping system and non-availability of buyers for rice straw. Farmers need to get clear fields within short time frame at any cost to ensure the timely sowing of next crop (wheat) without any hindrance in farm operation offered by loose straw. It takes time to manage loose straw by mechanical operation to ensure smooth sowing of next crop in standing stubble which compile farmers to go for straw burning. Field burning of crop residue (FBCR) was not given much attention by policy makers in last two decades because it was at a small scale, but nowadays, it is counted as the serious agricultural pollutant, which is directly impacting environment and human health and causes global warming as burning produces greenhouse gases. In the harvesting season Punjab, Haryana, Western Uttar Pradesh and Delhi face heavy smog problem because of this unhealthy practice and soil fertility is also deprived. In the IGP, rice–wheat is a major cropping system and both crops produce a lot of surplus residues which is ultimately disposed of by burning in the field particularly the rice residues. Nowadays, government and courts have zero tolerance against FBCR. Strict laws including heavy penalties and imprisonment against offenders are already in place. In the absence of suitable and economical viable alternative, farmers are still compelled to follow this practice as it is otherwise a big headache for farmers. We need to manage on-farm and post-harvest management of crop residues either by modification in machineries, educating farmers, adjustment in the cropping system and utilizing rice straw in industry and power generation. In this review, efforts have been made to cover major aspects related to rice residue management in rice–wheat cropping system (RWCS) of India.