Crop yield and soil quality of soya bean-maize rotation in response to 8-year keep stubble with no tillage practices on the Northeast China

Abstract

Conservation tillage helps maintain soil structure, reduces erosion and improves water retention, while little is known about the drivers for the improvement of crop yield. To explored the key mechanisms responsible for enhancing crop yields, we set up two conventional tillage practices (DT: Deep tillage 30 cm, SRT: shallow rotary tillage 15 cm) and two conservation tillage practices (NT: The straw is removed after the crop is harvested and no tillage is carried out, KSNT: Leave high stubble during harvest, and leave straw and ‌stubble on the surface without tillage treatment) from 2016. Results showed that compared with DT and SRT, KSNT and NT significantly increased soybean yield by 115.52–171.3 kg·km⁻², and maize yield by 723.02–863.24 kg·km⁻². In 2022 and 2023 years, compared with DT and SRT, KSNT significantly increased soil total nutrients, available nutrients, enzyme activity, and microbial biomass, followed by NT. In addition, KSNT significantly altered the soil bacterial and fungal communities structure, increased the diversity of soil bacterial and fungal, and bacteria appeared to be more sensitive to tillage systems than fungal communities. Soil quality index (SQI) in NT and KSNT was improved compared with DT and SRT, which was associated with crop yield. Our study found that KSNT increased crop yield by improving soil quality, reducing soil erosion, reshaping bacterial and fungal microbiota, and it was a suitable tillage method for the Northeast region.