Erosion-deposition positively reconstruct the bacterial community and negatively weaken the fungal community

Abstract

Soil erosion and deposition are general ecological processes that have been widely described in terms of their effects on the physical and chemical properties of soil. However, their effects on soil microbes remain unclear, especially how microbial communities respond to erosion–deposition in soils with different organic carbon levels. A long-term field experiment was conducted to examine the effects of erosion and deposition on soil microbial communities across full slopes with different organic carbon levels on the Loess Plateau of China. The results showed that erosion reduced soil bacterial alpha diversity, weakened bacterial network complexity while deposition increased bacterial alpha diversity, and enhanced the complexity of the bacterial network. However, both erosion and deposition caused a decrease in fungal alpha diversity and network complexity. There was a weak reverse cooperative covariation relationship between bacterial and fungal alpha diversity. There was a higher bacterial and fungal diversity at the eroded and depositional sites with high soil organic carbon (SOC) level than low and medium SOC levels. An increase in the SOC level effectively strengthened the network complexity of bacteria and fungi at the eroded and depositional sites.. Erosion-deposition and SOC levels significantly increased variation in bacterial community structure. In contrast, the fungal community structure only differed at the eroded and depositional sites at high SOC levels. The key factors driving variation in bacterial community structure in soil properties were not significantly affected by SOC levels. Conversely, key factors resulting in differences in fungal community structure were regulated by the SOC level. Our results demonstrate that erosion–deposition reconstruct the bacterial community and weakens the fungal community, organic carbon regulate soil microbial communities and functions by controlling earth surface processes induced by erosion–deposition.