Context

• Ecologically sustainable and environmentally safe management of agricultural wastes, technically called crop residues (CR), is one of the major challenges in India. 
• Stubbles, stalks, stover, husk, bran, bagasse, and molasses are generally classified under CR in the Indian context. These residues, once thought to be waste, are now regarded as an important natural resource due their versatile utility. 

Uses of CRs

• CRs are primarily used as bedding material for livestock, animal feed, soil mulching, bio-gas generation, bio-manure and compost, thatching for rural homes, mushroom cultivation, biomass energy production, fuel for domestic and industrial use, etc. 
• With the help of innovative technologies, CR can be converted into a variety of value-added products such as papers, boards, eco-panels, etc. 
• In spite of such practical and beneficial options, a large portion of CR is burned ‘on-farm’, primarily to clear the field for sowing the next crop. 
• This destructive activity deteriorates soil properties and fertility, along with ambient air quality. 

Problem and Perspectives

• Every year India, about 683 million tonnes CRs are produced, of which nearly two thirds are contributed by cereal crops. Nearly 500 million tonnes of residues are recycled in various sectors like industrial, domestic, and livestock fodder but a surplus of 178 million tonnes is left without any single use. 
• Nearly half of it is burned in fields across the states, with Punjab, Haryana, and Uttar Pradesh being the major defaulters. 
• Soil health greatly deteriorates due to the loss of organic matter and other soil nutrients. 
• On the other hand, if the CR is incorporated or retained in the soil itself, it gets enriched, particularly with organic carbon nitrogen. 
• Frequent burning of CRs leads to a complete loss of microbial population and reduces the level of nitrogen and carbon in the top 0-15 cm of the soil profile, which is critical for the development of the root system of crops. 
• The burning of CRs is a potential source of greenhouse gases, which are responsible for aggravating the global calamity of climate change releasing carbon dioxide, carbon monoxide, methane, sulphur oxide, and nitrogen oxide gases. 
• Besides, burning of CRs also emits a large amount of particulates (PM-2.5 and PM-10), which can remain suspended in the air for a long time and travel long distances in the wind. 
• The emission of particulates from the burning of CRs is 17 times higher than emissions from other sources such as motor vehicles, waste incineration, and industrial waste. Besides respiratory, skin, and eye problems, inhaling particulates can aggravate existing pulmonary and cardiac conditions, which may lead to premature death. 

Major Factors

• In spite of many long term damages to soil and human health, farmers in north-western India often opt for the burning of paddy stubbles, mainly due to three factors:
  • A shortage of farm labour at a critical time of field operation; (only 10 to 20 days)
  • A very short window for the preparation of the field for the next wheat crop and
  • Large-scale use of combine harvester for the harvesting of paddy (they leave nearly 20-30 cm of stubble on the ground, which needs to be removed or incorporated into the field for sowing the next crop) 
• There are implements like rotavators, happy seeders, super seeders, etc. that help to manage stubbles in the field. But majority of farmers are not inclined to invest in such machines, while others can’t afford the cost. 
• Farmers take up the burning of stubbles as a convenient, time-saving, and cost-saving practice to prepare fields for the next in record time.

Regulations and Solutions

• The National Green Tribunal, in 2015, prohibited agricultural residue burning in any part of the NCT of Delhi and the states of Punjab, Rajasthan, Uttar Pradesh, and Haryana. 
• During 2018-19, a new and comprehensive central sector scheme on CR management was launched with a multifaceted strategy. 
• Under this scheme, financial assistance @50% is provided to the farmers for purchase of CRM machinery, and @80% is provided to cooperative societies, Farmer Producer Organisations and Panchayats for the establishment of Custom Hiring Centres in villages. These centres provide CRM machinery to farmers on rental basis at affordable rates. 
• The Indian Council of Agricultural Research has developed Pusa Decomposer technology to biologically decompose paddy stubbles in the farm. It’s a microbial solution available both in liquid and capsule form for accelerated decomposition of straw. 
• Its application makes the field ready for wheat sowing in 25 days, and enhances the chemical, biological, and nutritional profile of soil. 
• Crop residues can be utilised as animal bedding and then placed in dung pits to make compost. 
• A special product called biochar can be made from rice straw, which is a carbon-rich material used as a soil amendment. Its application improves soil fertility, carbon storage, and water filtration. 

Conclusion

• In addition to technical and financial support, intensive educational campaigns and awareness camps are also required to have the best impact in addressing the issue of CR burning.