Alternate establishment and water saving techniques on prop performance and net global warming potential under an intensively managed rice ecosystem in subtropical India

Rice establishment and water management on GHG emission Rice cultivation under conventional flooded conditions significantly contributes to greenhouse gas (GHG) emissions, particularly methane (CH4). This study evaluates the impact of alternate rice establishment methods and water-saving irrigation techniques on crop performance, GHG emissions, and global warming potential (GWP) in a subtropical Indian rice ecosystem. Direct-seeded rice (DSR) and the system of rice intensification (SRI) reduced CH4 and CO2 emissions by approximately 40% while increasing N2O emissions by 57.1% compared with traditional transplanted rice (TPR). The alternate wetting and drying (AWD) irrigation method further reduced total GHG emissions by 26.9% relative to continuous submergence. SRI demonstrated a 5.7% yield advantage over TPR and yielded 9.1 and 15.2% more grain than wet-DSR and dry-DSR, respectively. The economic analysis indicated that SRI provided the highest net returns (₹45,804 ha−1) and benefit-cost ratio (2.21), followed by AWD-based irrigation, which achieved net returns of ₹48,251 ha−1 and a benefit-cost ratio of 2.24. Despite increased N2O emissions, the overall GWP was substantially reduced under AWD irrigation and SRI or both the DSR establishment methods, making them viable alternatives for climate-smart rice production in subtropical India.