Closing the Loop on Crop Residues: Technological, Environmental and Policy Pathways for Burning-Free Climate-Smart Agriculture

Abstract

The open-field burning of crop residues remains one of the most persistent, and most visible, failures of post-harvest resource management in global agriculture, undermining air quality, soil health, and climate mitigation goals all at once. Despite decades of regulatory bans, technological substitutes, and farmer awareness campaigns, the practice continues across major cereal-growing regions of South Asia, East Asia, and beyond, sustained by tight harvest-to-sowing windows, mechanised combine harvesting, labour scarcity, and the limited private return offered by alternative management options. This review draws together recent peer-reviewed evidence on the scale and drivers of crop residue burning, its environmental, climatic, and human-health consequences, and the technological, agronomic, and policy routes available for moving towards burning-free, climate-smart residue management. In-situ conservation agriculture technologies, exemplified by zero-tillage seeding machinery, are considered alongside ex-situ valorisation routes that include anaerobic digestion, pyrolysis-derived biochar, bioethanol production, and densified bioenergy feedstocks. The review also examines the soil organic carbon, greenhouse gas, and agroecological trade-offs that come with retaining residue rather than burning or removing it, drawing on recent global and regional meta-analyses. Particular attention is paid to the economic logic behind farmers' burning decisions, and to how regulatory bans, fiscal incentives, custom-hiring infrastructure, and accountability mechanisms within sub-national bureaucracies compare in their ability to shift burning behaviour at scale. The evidence assembled here suggests that no single technology or policy lever is sufficient on its own: lasting movement away from burning depends on profitable on-farm alternatives, working markets for off-farm residue valorisation, and credible, locally enforced governance all being in place together. The review closes by proposing an integrated framework linking agronomic, market, and institutional levers, and by identifying priority gaps in current knowledge concerning long-term soil and biodiversity outcomes, the scalability of decentralised bioenergy supply chains, and the equity implications of mechanisation-led residue policy for smallholder farmers.