Crop residue burning: causes for global warming
Author: Saroj Devi
India is an agrarian country and produced a record of 256.5 million tonnes of food grains in 2014-15, a significant step towards meeting the food requirement of explosively growing population and thus food security. It also produces a large quantity of crop residues or agriculture biomass (more than 500 million tonnes) annually (Economic Survey, Govt. of India, 2014-15). This amount will increase in future as with growing populations because there is a need to increase the productivity also.
Agricultural residues are the biomass left in the field after harvesting of the economic components i.e., grain. Large quantities of crop residues are generated every year, in the form of cereal straws, woody stalks, and sugarcane leaves/tops during harvest periods. These residues are used as animal feed, thatching for rural homes, residential cooking fuel and industrial fuel.
However, a large portion of the crop residues is not utilized and left in the fields. The disposal of such a large amount of crop residues is a major challenge for sustainability of Indian agriculture. To clear the field rapidly and inexpensively and allow tillage practices to proceed unimpeded by residual crop material, the crop residues are burned in situ.
A large portion of them is burnt in field primarily to clear the remaining straw and stubble after the harvest. The problem is more severe in the irrigated agriculture, particularly in the mechanized rice-wheat system of the northwest India
Indian agriculture generates approximately 500 Mt of crop residues are generated every year (MNRE, 2012). Generation and end use of these crop residues depends on the crops grown, cropping intensity and productivity in different regions of India.
The generation of crop residues is highest in Uttar Pradesh (60 Mt) followed by Punjab (51 Mt) and Maharashtra (46 Mt).Among different crops, cereals generate maximum residues (352 Mt), followed by fibres (66 Mt), oilseeds (29 Mt), pulses (13 Mt) and sugarcane (12 Mt) .The cereal crops (rice, wheat, maize, millets) contribute 70% while rice crop alone contributes 34% to the crop residues. Wheat ranks second with 22% of the crop residues whereas fibre crops contribute 13% to the crop residues generated from all crops. Among fibres, cotton generates maximum (53 Mt) with 11% of crop residues. Coconut ranks second among fibre crops with generation of 12 Mt of residues. Sugarcane residues comprising of tops and leaves, generate 12 Mt, i.e., 2% of the crop residues in India. Maharashtra contributes maximum to the generation of residues of pulses (3 Mt) while residues from fibre crops are dominant in Andhra Pradesh (14 Mt). Gujarat and Rajasthan generate about 6 Mt each of residues from oilseed crops.
Therefore, an efficient utilization of such cereal crop residue is of great importance not only for minimizing the environmental impact, risk to human health but also for obtaining a higher profit. Using the agricultural by products as sources for fibers could help to address the concerns on the future price and availability of both the natural and synthetic fibers in current use and also help to add value to the food crops.
1. (Economic Survey, Govt. of India, 2014-15).
2. http://www.fibre2fashion.com, Ministry of New and Renewable Energy (MNRE, 2012)
About Author / Additional Info:
PhD scholar at Delhi university