Long-term ditch-buried straw return alters soil water potential, temperature, and microbial communities in a rice-wheat rotation system

• DB-SR affects soil hydrothermal and microbial processes.
• DB-SR reduced soil water potential and increased soil temperature.
• DB-SR altered soil microbial community composition and increased functional diversity.
• DB-SR improved wheat yields and showed good potential for application at the field scale.

As a novel soil tillage practice, ditch-buried straw return (DB-SR) has exhibited positive effects on soil carbon sequestration, nitrogen retention and rice yield in previous studies. However, little is known about how long-term DB-SR affects soil hydrothermal and microbial processes. Our objective is to test whether DB-SR will alter the soil water potential, temperature and microbial community in a wheat field following rice cultivation. In this study, we found significant alterations in soil water potential, temperature, and microbial communities driven by DB-SR. On average, soil water potential was significantly reduced by 37.33% and 17.56% under DB-SR to a depth of 20 cm (DB-SR-20) and 40 cm (DB-SR-40), respectively. DB-SR-20 increased soil mean daily temperature and daily range of temperature more than DB-SR-40, possibly caused by decreased water content, especially at soil depths of 10 and 15 cm. Both DB-SR-20 and DB-SR-40 led to distinct shifts in soil bacterial and fungal community composition. DB-SR-20 significantly increased the activities of peroxidase, cellobiohydrolase, urease, and acid phosphatase by 3.5%, 75.0%, 81.4% and 41.7%, respectively, but had no effects on β-d-glucosidase activity. DB-SR-40, in contrast, significantly increased the activities of peroxidase and cellobiohydrolase by 2.4% and 36.0%, respectively, but showed no effects on urease and acid phosphatase. It did, however, reduce β-d-glucosidase activity by 15.0%. Overall functional diversity was increased by 29.9% under DB-SR-20 but was not affected by DB-SR-40. Our results suggest that these improvements in soil ecological processes driven by DB-SR will promote wheat yield in a rice-wheat rotation system.