Abstract
•Soil microorganisms redistribute within the sloping land during and after erosion.•Physical mechanism drives changes of soil microbial abundance during erosion.•Soil properties shaped by erosion control microbial dynamics after erosion.•Bacterial and fungal abundance was positively correlated with soil organic carbon.•Bacteria and fungi exhibit different responses to erosion in microbial communities.
Water erosion significantly affects soil properties, and microbial communities are likely to respond to this disturbance, thereby considerably influencing soil organic carbon (SOC) dynamics. This study investigated the impact of water erosion on the soil microbial communities in a hilly, sloped cropland in subtropical China. To this end, 1h rainfall was simulated, and the soil samples collected from three plots (I, II, and III) during and for 132h after rainfall simulation were analyzed. The two-stage variations in soil microbial abundance and community structure were identified by quantitative polymerase chain reaction and denaturing gradient gel electrophoresis, respectively. During rain, severe water erosion significantly reduced the bacterial abundance (BA) and fungal abundance (FA) in plot II. Most of the soil properties of the entire land significantly changed because of erosion. The overall redundancy analysis results illustrate that during the subsequent 132h, soil pH strongly controlled the Shannon index of bacterial diversity and soil moisture had a significant negative correlation with FA and the Shannon index of fungal diversity. By contrast, a positive correlation was found between BA, FA and SOC. These results suggest that the dynamics of microbial communities are closely related to erosion-induced changes in soil properties. Bacteria and fungi differentially respond to these changes. Thus, merely analyzing the variations in SOC pool content is therefore insufficient. Elucidating soil microbial dynamics and gaining insight into the dynamics of erosion-sensitive functional groups or species are necessary for evaluating eroded carbon dynamics.