ICAR stubble burning solution shows promising results at trials in Delhi, Punjab

A proprietary microbial solution developed by the Indian Council of Agricultural Research (ICAR) could be a breakthrough in the hunt for a solution to crop-residue burning, a major cause of winter pollution in north India, results from trials in Delhi and Punjab show.

“The ICAR’s invention, named Pusa, decomposes crop residue, including paddy straw, and turns it into manure in about 25 days, thus eliminating the need to burn paddy stubble. It could be a breakthrough if adopted with an integrated approach,” YV Singh, principal scientist of microbiology at Indian Agricultural Research Institute (IARI), an affiliate institution of the ICAR which developed the solution, told HT.

Singh said the technology had an efficacy range of 70%-80%, citing results from its use in 24 villages in Delhi this October. This means it can successfully decompose up to 80% of the straw in a given area.

The Delhi government adopted the technology from IARI to prevent burning of paddy stubble in about 700 hectares of rice fields, a project that cost Rs20 lakh.

The institute has applied for a patent for the technology and is in the process of signing contracts with private firms to commercially market the product, Singh said.

Assuming farmers in Punjab burn paddy straw in at least two million hectares, it will cost the state Rs571 crore to fund the use of Pusa decomposer to eliminate stubble burning, HT’s calculation based on the Delhi government’s costs show.

Farmers across Punjab, Haryana and Uttar Pradesh typically harvest paddy in October and then set their fields on fire to clear rice stalks for the next crop. It is the fastest and cheapest way to clear the fields of unwanted stalks.

The burning of more than seven million hectares of crop residues has emerged as one of the biggest sources of winter pollution, resulting in weeks-long smog in New Delhi every October and November.

Burning paddy straw has emerged as a big problem in the past two to three decades as farmers have shifted to mechanised combine harvesters, which cut the grainy part of a rice plant, leaving the stalk intact.

While the straw from basmati rice, which is mostly exported, is soft enough to be used as fodder, the residue of other rice varieties, which account for most paddy acreage, is too stiff to be of any use. Farmers say they have few effective, affordable alternatives to burning.

Pusa decomposer comes in the form of capsules that contain an activated package of eight strains of fungi, Singh said. To prepare a solution of 25 litres, farmers need to add four capsules of the decomposer, along with jaggery and checkpea flour, to water. Within a week, a good layer of fungi admixture is formed. To decompose paddy stubble in one hectare, farmers need to spray 25 litres of this solution.

According to A. Amarender Reddy, the principal scientist at the Central Research Institute for Dryland Agriculture, microbial agents in the solution act on the straw to make it soft, break down its components and release nutrients into the soil.

The IARI is trying to popularise its solution in Punjab and Haryana, where farmers have used it in about 12000 hectares, which is just a fraction of the total rice acreage. “Some form of subsidy may be needed to popularise its use,” said Singh said.

The farm ministry already runs a programme called “Promotion of Agricultural Mechanization for In-Situ Management of Crop Residue in the State of Punjab, Haryana, Uttar Pradesh & NCT of Delhi” with funds worth Rs1,151 crore from 2018-19 to 2019-20 to subsidise machinery needed for management of crop residue. According to data from the Punjab Remote Sensing Centre, the state witnessed 40,000 incidents of farm fires on November 5.

Five years ago, the National Green Tribunal, an environmental court, banned stubble burning. Punjab authorities fine farmers if they defy the ban but such coercive methods have proved to be of little help.