Enhanced yields and soil quality in a wheat–maize rotation using buried straw mulch

BACKGROUND Straw return may improve soil quality and crop yields. In a 2‐year field study, a straw return method (ditch‐buried straw return, DB‐SR) was used to investigate the soil quality and crop productivity effects on a wheat–corn rotation system. This study consisted of three treatments, each with three replicates: (1) mineral fertilisation alone (CK0); (2) mineral fertilisation + 7500 kg ha−1 wheat straw incorporated at depth of 0–15 cm (NPKWS); and (3) mineral fertilisation + 7500 kg ha−1 wheat straw ditch buried at 15–30 cm (NPKDW). RESULTS NPKWS and NPKDW enhanced crop yield and improved soil biotical properties compared to mineral fertilisation alone. NPKDW contributed to greater crop yields and soil nutrient availability at 15–30 cm depths, compared to NPKWS treatment. NPKDW enhanced soil microbial activity and bacteria species richness and diversity in the 0–15 cm layer. NPKWS increased soil microbial biomass, bacteria species richness and diversity at 15–30 cm. CONCLUSIONS The comparison of the CK0 and NPKWS treatments indicates that a straw ditch buried by digging to the depth of 15–30 cm can improve crop yields and soil quality in a wheat–maize rotation system.