Impact of biological soil crust on soil physical and chemical properties and bacterial community structure in Hilly Loess Plateau, China

Biological crusts can effectively reduce rainfall kinetic energy and runoff erosion, reduce soil loss, and maintain soil nutrients. It is of great significance to the ecological restoration of the hilly and gully areas of the Loess Plateau. However, there is currently a lack of bacterial communities for biological crusts in the hilly areas of the Loess Plateau. In-depth study of the structure.In this paper, 16S rRNA sequencing analysis was carried out on the algae-moss crust, the surface of bare soil and the soil below the crust. Combined with soil physical and chemical factors, the effect of algae-moss crust on bacterial community structure in loess hilly area was systematically expounded.The results show that the algae-moss crust can significantly increase the content of conventional nutrients such as available phosphorus, total nitrogen and organic matter in the soil in the hilly and gully regions of the Loess Plateau.In addition, the development of the algae-moss mixed crust layer will also form its own specific bacterial community structure. In the algae-moss crust layer, the Rhodobacter and Cyanobacteria will be specifically enriched.Through Redundancy analysis, it is found that these specifically enriched species may participate in the process of photosynthesis and nitrogen fixation, thereby increasing the organic carbon and organic nitrogen content in the soil. Biological crusts play an important role in soil development and mineral nutrient improvement in hilly and gully regions of the Loess Plateau. The research results provide an important microbiological theoretical basis for the ecological restoration of the hilly and gully regions of the Loess Plateau.