Promising water-saving strategies for mitigating greenhouse gas emissions while ensuring rice yield in paddy fields: Evidences from a global meta-analysis

Water-saving irrigation practices (WSIs) are increasingly promoted to address water scarcity and sustain global rice production, with proven potential to reduce global warming potential (GWP) in low water-use efficiency paddy fields. However, most studies are site-specific, leading to inconsistent effects on yield and greenhouse gas (GHG) emissions. To address this uncertainty, we conducted a global meta-analysis synthesizing 2277 observations from 108 publications to evaluate the impacts of WSIs on rice yield, CH4, N2O, GWP, and greenhouse gas intensity (GHGI). Compared with traditional flooding irrigation (FI), WSIs maintained grain yield while reducing CH4 emissions by 71.0 %, GWP by 54.7 %, and GHGI by 51.7 %, but increased N2O emissions by 39.5 %. Among WSI types, alternate wetting and drying irrigation (AWD), controlled irrigation (CI), and wet irrigation (WI) achieved comparable mitigation effects, whereas shallow irrigation (SI) and intermittent irrigation (IR) were less effective. Yield increased under CI (+4.5 %), SI (+3.4 %), and IR (+3.1 %), remained stable under AWD, and decreased under WI (−2.5 %). WSIs achieved the greatest GWP reductions in light loam soils, at temperatures of 25–30 °C, with cumulative precipitation below 400 mm, and at soil pH ≤ 6.5. Nitrogen application rate did not significantly influence GWP mitigation, whereas biochar amendment increased yield by 2.3 % and reduced GWP by 84.9 %. In addition, WSIs increased net eco-economic benefits compared with FI. Optimizing WSI selection based on regional conditions and integrating with complementary agronomic measures can reduce non-CO2 emissions while sustaining or improving rice yield, supporting climate change mitigation and sustainable production.