A meta-analysis on the mitigation measures of methane emissions in Chinese rice paddy

Mitigating methane emissions from the rice paddy in China proves to be one of the most vital approaches to achieving the global methane reduction target, but the heterogeneity and effectiveness of existing methane reduction strategies and the influencing factors of their mitigation effects remain not systematically explored for China. We employed a meta-analysis to evaluate ten identified methane mitigation technologies in China, based on field experiments data. We show the methane mitigation effects vary in descending order, as water-fertilizer coupling management > water management > tillage management > fertilizer management. In particular, the water-fertilizer coupling management could reach a reduction of 67.27 %, which is markedly higher than employing singular practices and eliminates the "trade-off" among individual reduction measures. Overall, the mitigation effects are subject to various factors, such as experimental year, soil pH, and precipitation, leading to varying effectiveness across regions. Intermittent irrigation and alternate wetting and drying irrigation have high abatement potential in southern China, while urea and variety yield better results in northern China. Although China's methane reduction efforts are at the forefront among Asian countries, the potentially exacerbating methane leakage issues due to its increasing import of rice from Southeast Asia deserve a special focus as well.