Effects of 15-year straw returning on soil carbon composition and microbial community under wheat-maize rotation in the Huang-Huai-Hai Plain

The straw represents a valuable agricultural resource in crop production. Appropriate returning of straws to field can effectively enhance soil fertility and increase crop yield. In this study, we investigated the effects of the different straw returning modes on soil organic carbon components, enzyme activities, and microbial community based on a 15-year field experiment conducted at the Crop Cultivation Scientific Observatory in East China, subordinated by the Ministry of Agriculture and Rural Affairs. In detail, four straw-returning modes were carried out, control with no straw return (CK), crushed wheat straw mulching in summer maize season (T1), crushed wheat straw mulching in summer maize season and crushed maize straw was buried in winter wheat season (T2), crushed maize straw was buried in winter wheat season (T3).