Impact of stubble burning on soil health and ecology: A comprehensive review

Abstract

Rice-wheat cropping system being intensive, generates substantial post-harvest residue. The widespread practice of burning residue on-field, particularly in Punjab, Haryana, and Uttar Pradesh, poses severe environmental and health challenges. This review synthesizes the detrimental effects of this stubble burning practice, which alone accounts for one-fourth of the air pollution. In 2017-18, an estimated 116 million tonnes of residue were combusted, releasing substantial greenhouse gases (176.1 Mt CO2) and hazardous particulate matter (0.453 Mt PM2.5), linked to respiratory ailments and cardiovascular risks. Furthermore, burning leads to significant annual losses of crucial soil nutrients, including 3850 million kg of organic carbon and substantial amounts of nitrogen, phosphorus, and potassium, while also harming soil microflora. Despite governmental bans, farmers often resort to burning due to its perceived efficiency and cost-effectiveness, especially with the limited 15-day window between rice and wheat cultivation. This paper explores sustainable alternatives such as in-situ residue incorporation using machinery like super seeder and happy seeder, composting (including vermicomposting to address the high C:N ratio of rice straw), bioenergy production (with potential to meet 17% of India’s energy demand, particularly in Uttar Pradesh, Maharashtra, and Punjab), and biochar, which offers carbon sequestration and soil enhancement benefits. While wheat stubble finds some use as animal fodder (around 45% in parts of Punjab), rice stubble utilization is limited due to its silica content. Other potential applications in paper and mushroom industries are also discussed.