Effects of tillage and straw management on grain yield and SOC storage in a wheat-maize cropping system

Abstract

Climate change significantly impacts the prevailing climatic conditions and crop productivity. Although soil organic carbon (SOC) sequestration can mitigate global climate change, the SOC sequestration capacity and crop production under conservation tillage are unclear. This study assessed the dynamics and relationship between SOC storage and grain yield under conservation tillage over eight years. Four tillage and straw management treatments, including (i) no-tillage with straw retention (NTS, conservation tillage), (ii) conventional tillage with straw retention (CTS), (iii) no-tillage without straw retention (NT), and (iv) conventional tillage without straw retention (CT), were conducted. The results showed that the SOC content and storage in the 0–10 cm soil layer were significantly higher in NTS than in the other treatments. In contrast, SOC content and storage in the 10–30 cm layer were lower in NTS than in CTS (P < 0.05). Overall, the average SOC storage in the 0–30 cm was significantly higher in the straw returning treatment than without straw returning (P < 0.05). Moreover, SOC storage was not significantly different between NTS (35.7 Mg ha−1) and CTS (35.9 Mg ha−1). The wheat yield was lowest under NTS. Furthermore, the yield coefficient of variation under NTS was significantly lower than under CTS (P < 0.05). Maize yield was not significantly different between NTS and CTS. SOC storage in the 0–10 cm soil layer had a quadratic relationship with annual yield. These results indicate that NTS can positively sequester carbon, especially for the surface layer. However, to mitigate climate change and food insecurity, further advancements in NTS technology are required to improve crop yields and carbon sequestration capacity.