'Zero-tillage' farming can reduce the hazards of crop-residue burningWith wheat harvesting having already begun, the northern wheat-growing states will soon turn into virtual smoke chambers when the stubble from the harvest is burnt off. Even Delhi, which is located near the intensive wheat-growing zone, is not unaffected by smoke pollution. A similar situation, in fact, will occur after the paddy crop is cut. In most agriculturally progressive states, where multi-cropping is in vogue, people face the ill-effects of torching crop residues. Smoke and the hanging soot particles spewed by smouldering agricultural fields cause myriad problems, including health hazards such as impaired breathing. Besides, the atmosphere is polluted with greenhouse gases like carbon dioxide, methane and nitrous oxide, contributing to global warming and climate change. Worse, it results in a colossal loss of vital plant nutrients contained in crop residues, such as nitrogen, phosphorous, potash, carbon and numerous micronutrients which, if incorporated back into the soil, can enhance its fertility and restore its physical health. Going by a policy paper (No 58) on the management of crop residues, issued recently by the National Academy of Agricultural Sciences (NAAS), 500 million tonnes of crop waste is generated annually. This waste is commonly used as animal feed, manure, fuel and industrial raw material. The rural poor also use it for thatching. However, a sizeable part of the remnants - estimated at 80 to 140 million tonnes - unutilised and is usually disposed of by burning. In intensive farming areas, where harvesting operations have been largely mechanised, the extent of the stubble left in fields is usually much higher than in manual harvesting. In these areas, the time gap between reaping one crop and planting the next is usually short, forcing farmers to burn the waste rather than gathering these for use. The increasing shortage of farm labour and rising wage rates, largely owing to the implementation of the Mahatma Gandhi National Rural Employment Guarantee Act, has exacerbated the menace of residue burning.
Farmers find it both cost-effective and time-saving to dispense with this waste. Although some states have enacted laws to make crop-residue burning a punishable offence, these laws have remained, by and large, on the statute books without being enforced effectively. A good option to effectively manage crop residues without torching them in situ is through conservation agriculture, in which a new crop is sown without tilling the field, after the previous crop is cut. This system, also known as "zero tillage" or "minimum tillage", is catching up the world over and is now being promoted in the vast Indo-Gangetic plains where rice-wheat crop rotation predominates. About seven per cent of the total farmed area in the world is estimated to have already been brought under this method of cultivation. The NAAS policy paper projects conservation farming as an environment-friendly system of sustainable agriculture. This approach offers several advantages - it helps improve soil-health, minimise soil-erosion, reduce cultivation costs and water requirement, lift crop yield and ensure better livelihoods for farmers. Studies conducted in India and its neighbouring countries have borne out many of these beneficial outcomes of conservation farming, including its role in making agriculture sustainable over the long period. However, conservation agriculture requires specially designed machines for some farm operations, notably seed sowing and fertiliser application. Since everybody may not be able to afford this equipment, NAAS suggests providing financial assistance to unemployed rural youth to procure these machines for providing custom-hire services to the farmers. Self-help groups can also take up this task. Also, farmers who adopt conservation agriculture should be helped to claim carbon credits, since conservation cultivation promotes carbon sequestration even while curtailing harmful gas emissions. The NAAS policy paper also advocates for the introduction of crop-residue management as a subject at undergraduate and post-graduate levels in agricultural universities to build technically competent human resource. These and other well thought-out suggestions mooted in the paper merit urgent attention because of their far-reaching implications for agriculture, environment and human health.