Long-term straw mulching enhanced topsoil fertility and improved yield stability and sustainability in soybean production

Achieving stable and sustainable soybean production under increasing climate variability and soil degradation remains a global challenge. Straw mulching is promoted to increase soybean seed yield in arid and semi-arid agricultural systems, but its long-term impacts on soil fertility and yield stability remain poorly quantified. We conducted a long-term field experiment, involving three treatments: straw removing (SR), straw mulching (SM), and straw crushing (SC). SM increased soil enzymes activity and improved topsoil nutrients. Among the three treatments, the SM exhibited the highest mean weight diameter (2.12), while the lowest soil solid phase proportion (49.09%). SM resulted in the longest chlorophyll retention duration in soybean leaves (135.55 d), followed by the SC (120.81 d) and SR (95.25 d). Furthermore, at the R1 stage, the SM exhibited the highest leaf area index (LAI) and biomass, both of which showed a significant positive correlation with seed yield. Compared with SR and SC, SM increased seed yield, yield stability, and yield sustainability by an average of 17.76, 73.64, and 15.42%, respectively. Long-term retention of crop residues represents a scalable, low-input strategy to rebuild soil fertility, buffer climatic stress, and secure yield stability – contributing to global goals for sustainable agriculture and food security.