Quantitative assessment of different straw management practices on soil organic carbon and crop yield in the Chinese upland soils: A data-driven approach based on simulation and prediction model

Straw return is a sustainable management practice that improves soil fertility, enhances crop yield and soil organic carbon (SOC), while the extent of its impact vary based on various management practices, as well as climate and soil properties. However, the overall effects of straw return combined with tillage (deep tillage-DTS, rotary tillage-RTS, and no-tillage-NTS) and fertilization (balanced-BFS, and unbalanced-UFS) on crop yield and SOC stock varied significantly. Our aim was to evaluate the overall suitability of straw return in conjunction with combined tillage and fertilizer effects on crop yield and SOC stock within wheat-maize cropping systems using meta-analysis and a random forest prediction model. Overall, straw return resulted in an 8.92% increase in crop yields and an 11.6% rise in SOC stock compared to straw removal, as simulated and predicted by the random forest model. For the combined effects of tillage and fertilizer with straw return resulted in significantly higher crop yield with DTS+BFS (14.9%) compared to RTS+BFS (6.11%) and NTS+BFS (6.19%). However, balanced fertilization with different tillage practices (NTS+BFS (14.6%), RTS+BFS (13.6%), and DTS+BFS (19.3%)) increased the SOC stock in compared to unbalanced fertilization with different tillage practices (NTS+UFS (7.44%), RTS+UFS (9.22%), and DTS+UFS (13.5%) during straw return. The random forest prediction model indicated consistent trends, showing that NTS+BFS had a more significant effect on SOC stock and crop yield in single cropping systems, while DTS+BFS had a greater impact in double cropping systems. The most important factors for yield and SOC stock were mean annual temperature and C input for NTS+BFS, as well as DTS. The study suggests that NTS+BFS is suitable for dry, wind erosion-sensitive regions, while DTS+BFS is suitable for humid, low-lying areas with double cropping systems.