Can cropland management practices lower net greenhouse emissions without compromising yield?

Smart cropland management practices can mitigate greenhouse gas (GHG) emissions while safeguarding food security. However, the integrated effects on net greenhouse gas budget (NGHGB) and grain yield from different management practices remain poorly defined and vary with environmental and application conditions. Here, we conducted a global meta‐analysis on 347 observation sets of non‐CO2 GHG (CH4 and N2O) emissions and grain yield, and 412 observations of soil organic carbon sequestration rate (SOCSR). Our results show that for paddy rice, replacing synthetic nitrogen at the rate of 30%–59% with organic fertilizer significantly decreased net GHG emissions (NGHGB: −15.3 ± 3.4 [standard error], SOCSR: −15.8 ± 3.8, non‐CO2 GHGs: 0.6 ± 0.1 in Mg CO2 eq ha−1 year−1) and improved rice yield (0.4 ± 0.1 in Mg ha−1 year−1). In contrast, intermittent irrigation significantly increased net GHG emissions by 11.2 ± 3.1 and decreased rice yield by 0.4 ± 0.1. The reduction in SOC sequestration by intermittent irrigation (15.5 ± 3.3), which was most severe (>20) in alkaline soils (pH > 7.5), completely offset the mitigation in CH4 emissions. Straw return for paddy rice also led to a net increase in GHG emissions (NGHGB: 4.8 ± 1.4) in silt‐loam soils, where CH4 emissions (6.3 ± 1.3) were greatly stimulated. For upland cropping systems, mostly by enhancing SOC sequestration, straw return (NGHGB: −3.4 ± 0.8, yield: −0.5 ± 0.6) and no‐tillage (NGHGB: −2.9 ± 0.7, yield: −0.1 ± 0.3) were more effective in warm climates. This study highlights the importance of carefully managing croplands to sequester SOC without sacrifice in yield while limiting CH4 emissions from rice paddies. Finding ways to cut greenhouse gas (GHG) emissions while maintaining crop productivity is paramount. We investigated the integrated effects of smart management practices on net GHG emissions and grain yield. We found that the mitigation effects on net GHG emissions for upland crops were dominated by soil organic carbon (SOC) sequestration. For paddy rice, trade‐offs between SOC sequestration and CH4 emissions caused by different practices led to substantial differences in net GHG emissions. Our results show that we must carefully manage croplands to sequester SOC and limit CH4 emissions, especially for paddy rice, while maintaining grain yield.