Optimizing straw and nitrogen fertilizer resources for low-carbon sustainable agriculture

Straw as an important sustainable agricultural resource and its interaction with nitrogen (N) fertiliser may affect soil carbon sink and food security. Here, machine learning based on meta-analysis was conducted to assess the effect of straw and N input on soil organic carbon (SOC) and crop yield by compiling worldwide site-specific studies and high-resolution databases. The results highlight that the effects of straw return depend on management, climate, and soil properties. Meta-analysis results revealed that returning 8000–11,000 kg ha−1straw can achieve greater benefits. Moreover, the model forecasts demonstrate that optimizing straw and N input could increase surface SOC storage by 12 % (20.4 Pg) and global crop yield by 19.7 % (308 Tg). According to the optimization model, SOC storage and crop yield could further increase by 12.9 % (22.8 Pg) and 15.7 % (236.9 Tg) respectively by 2041–2060. These insights underscore the importance of optimizing straw and N input for sustainable agriculture under climate change.