Long-term green manuring reduces net greenhouse gas emissions in upland cropping systems in China

作者：Penghui Li, Hao Liang, Qiu Zhao, Jiudong Zhang, Libo Fu, Dabin Zhang, Han Mei, Rui Zhang, Na Zhao, Weidong Cao, Feng Zhou · 发表于：Farming System · 年份：2025 · DOI：10.1016/j.farsys.2025.100191 · 被引用次数：2 · 研究领域：Soil Carbon and Nitrogen Dynamics、Agroforestry and silvopastoral systems、Agronomic Practices and Intercropping Systems

Green manuring enhances multiple agroecosystem services functions, yet its impact on net greenhouse gas mitigation remains controversial, primarily due to a limited number of long-term experiments. To address these challenges, this study investigated the long-term effects of green manure (GM) rotations on 100-cm-depth soil organic carbon (SOC) sequestration, N 2 O emissions, and crop yields based on eight long-term experimental sites (7–16 years) in China’s upland cropping systems combined with process-based modeling. The results demonstrated that green manuring significantly increased SOC concentration by 8.8%–14.4% ( p <0.001) across 0–100 cm soil profiles compared to fallow system, with annual SOC sequestration rates reaching 0.95–1.16 Mg C ha -1 yr -1 ( p <0.001). Notably, topsoil layer (0–40 cm) contributed 67.5% of total profile SOC accumulation. Green manuring can replace approximately 40% of synthetic fertilizers of N while maintaining long-term yield stability, though with potential trade-offs in elevated N 2 O emissions. The optimal net global warming potential (NGWP) reached -16.47 Mg CO 2 -eq ha -1 yr -1 under GM-based system with 30% reduction in fertilizer N. Meanwhile, under the condition that GM substitution for fertilizer N achieved no yield reduction, the greenhouse gas intensity (GHGI) was optimized within the substitution rate range of 20%–40%. The results from process-based modeling demonstrate that substituting 30% of N fertilizer with GM achieves optima...