Harnessing Ratoon Cropping for Mitigating Greenhouse Gas Emissions.

Abstract

Ratoon cropping systems have gained increasing attention for their potential to mitigate greenhouse gas (GHG) emissions, including carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O). Building on the well-established root system of the previous crop, ratoon crops require no land preparation, sowing, or transplanting and need less fertilizer, water, and pesticides than annual crops while achieving earlier harvests, thereby reducing GHG emission intensity (GHGI) by 7.9-17.3% and N₂O emissions by 40.4-78.1%. Reduced fertilization, efficient water management, and integrated pest management can further curtail GHG emissions, while improved soil fertility, sustainable land management, and cover crop integration enhance soil carbon sequestration. Genetic improvement of ratoon crops can additionally enhance stress tolerance and resource use efficiency, reducing fertilizer requirements and ultimately lowering GHG emissions. This review also addresses ratoon cropping in dryland systems, including sugarcane, sorghum, cotton, and pigeon pea, highlighting their distinct GHG emission profiles and mitigation potential. Its innovative contribution is an integrated framework-synthesizing crop physiology, soil carbon processes, agronomic management, and genetic improvement-that evaluates GHG mitigation opportunities across both ratoon rice and dryland ratoon crops while explicitly addressing trade-offs, context-dependency, and evidence gaps.