Recovery of bacterial communities and functions of soils under ridge tillage and no-tillage after different intensities and frequencies of drying-wetting disturbances in agroecosystems of northeastern China

Abstract

Climate change is predicted to induce more frequent and intense drying-wetting disturbances in soils. Although the response of soil microbial communities and the functions they perform during, or shortly after, drying-wetting disturbances is well documented, the recovery of these components several weeks after the disturbances is still largely unknown, especially under different tillage treatments. In this study, we compared bacterial diversity and community composition, CO2 and N2O production rate, and activities of β-glucosidase, cellobiohydrolase and N-acetyl glucosaminidase extracellular enzymes in soils under no-tillage and ridge tillage treatments after different intensities and frequencies of drying-wetting disturbances. Soil bacterial diversity fully recovered after a month, but the recovery of bacterial community composition differed with tillage treatment. Bacterial community composition of soils under no-tillage recovered faster than that under ridge tillage, possibly related to higher abundances of copiotrophic bacteria in no-tillage soils. This suggests no-tillage treatment can buffer the negative impacts of drying-wetting cycles on the composition of soil bacterial communities. The recovery of soil functions showed a similar pattern for both tillage treatments but differed by function. While CO2 production rate did not recover, the N2O emission rate totally recovered. This result is closely related to the activity of soil enzymes catalyzing these processes. Our results demonstrate that soil functions related to C cycling can be altered by drying-wetting disturbances even if bacterial community composition and diversity are fully recovered under no-tillage, emphasizing the effects of climate change on ecosystem services. These findings provide important information about the resilience of agroecosystem functions under environmental perturbations, which could ultimately aid the development of evidence-based agricultural management in the face of conflicting land use pressures.