Different straw return methods have divergent effects on winter wheat yield, yield stability, and soil structural properties

Sustainable agriculture should aim to increase grain yield and yield stability while improving soil structure. Despite different straw return practices are widely recommended in agroecosystems targeting sustainable agriculture, few studies have concurrently explored their impact on grain yield, yield stability, soil structural properties, and any potential interactions between these variables. Therefore, we conducted a seven-year field experiment to investigate how different straw return practices affect grain yield, yield stability, and soil structural properties. The experiment included four treatments: straw removal (control), straw mulch (SM), straw incorporation (SI), and ammoniated straw incorporation (ASI). Our results showed that SM, SI, and ASI significantly increased grain yield by 12%, 13%, and 24% and yield stability by 4%, 11%, and 15%, respectively, relative to the control. Furthermore, SM, SI, and ASI increased soil mean weight diameter by 32%, 26%, and 34% and soil organic carbon (SOC) content within the > 2 mm soil aggregate fraction by 11%, 14%, and 14%, respectively; these two parameters also positively correlated with grain yield. Moreover, SM, SI, and ASI increased soil saturated hydraulic conductivity and soil water retention. Our findings suggest that the increased proportion of soil macro-aggregates with straw return enhances SOC content and grain yield, highlighting the need for further research on fundamental soil physical processes as potential drivers of sustainable agriculture.