- Research Article
- 10.1016/j.farsys.2025.100191
Long-term green manuring reduces net greenhouse gas emissions in upland cropping systems in China
- Nov 01, 2025
- Farming System
- Penghui Li + 10 more +10
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 optimal soil C sequestration while maintaining stable crop yields. These findings provide direct evidence that GM rotation increases C sequestration, addressing previous knowledge gaps in understanding the C sequestration and emission reduction effects of GM-based rotation. • GM increases SOC by 8.8%–14.4% in the 0–100 cm soil layer with a C sequestration rate of 0.95–1.16 Mg C ha -1 yr -1 . • Topsoil (0-40 cm) contributes 67.5% of total SOC accumulation under GM-based systems. • 30% N fertilizer substitution with GM optimizes yield stability and reduces NGWP by 16.47 Mg CO 2 -eq ha -1 yr -1 . • GM-based systems lower the greenhouse gas emission intensity at 20%-40% N substitution.
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