Mitigation Potential of Greenhouse Gas Emissions Through Nitrogen‐Water Management Optimization in Major Asian Rice Regions

Rice production represents a major global food source and a significant contributor to greenhouse gas (GHG) emissions. While nitrogen fertilization and water‐saving irrigation are recognized as effective GHG mitigation strategies in rice cultivation, their synergistic effects and underlying mechanisms remain inadequately characterized. Based on 2,689 observations from 203 peer‐reviewed articles across 129 sites in major Asian rice cultivation areas, this meta‐analysis quantifies the comprehensive impacts of coupled water‐nitrogen management on rice yield and GHG emissions. Results revealed that nitrogen fertilization alone increased yield by 38.26% but elevated global warming potential (GWP) by 56.98%, whereas Alternate Wetting and Drying (AWD) irrigation reduced CH 4 emissions (50.71%) and GWP (43.73%) without significantly affecting yield. Combined implementation of both practices increased yield by 46.67% while reducing yield‐scaled GWP (GHGI) by 36.17%. Under AWD conditions, nitrogen application rates of 180–270 kg ha −1 maximized GHGI reduction potential (42.31%). Random forest analysis identified soil pH, fertilizer type and precipitation as key determinants of mitigation efficacy. Our spatially‐explicit water‐nitrogen optimization model demonstrated that 67% of regional rice fields are suitable for AWD implementation, and that current nitrogen inputs could be reduced by 31% while maintaining yields and achieving a 49% reduction in GHGI. This study reveals critical water‐nitrogen synergistic mechanisms in rice agroecosystems and provides quantitative frameworks for optimizing management practices at regional scales, offering a sustainable pathway toward achieving future food security and climate change mitigation goals in Earth's most productive rice regions.