The Effect of Land Use on Bacterial Communities in Saline–Alkali Soil

Saline–alkali soil can inhibit the growth of crops as a consequence of cellular damage through oxidation of lipids and proteins and degradation of nucleic acids, ultimately leading to cell death. The bacterial community composition and diversity in saline–alkali soil across different land uses, such as agricultural land, forest land, and grassland, were evaluated using high-throughput sequencing of the bacterial 16S rRNA gene. Significant differences in the soil physicochemical characteristics and bacterial community among different land uses were observed in this study. The soil pH value and electrical conductivity were much higher in grassland soil than in agricultural and forest soils. There were high proportions of Actinobacteria and Proteobacteria (phyla) in agricultural and forest soils, while Actinobacteria, Bacteroidetes, Gemmatimonadetes were more predominant in grassland soil. The relative abundance of dominant taxa exhibited a highly significant correlation with soil pH, water content, EC, and organic matter. The percentage of species that are shared among the different soil samples ranged from 5.3 to 30.5%. The haloalkaliphilic Actinobacterial genus Nitriliruptor was detected in grassland but not in areas with other types of land use. Results of both heatmap and principal component analysis (PCA) indicated that the soil properties and bacterial communities in the areas studied have been greatly influenced by long-term land use by different management.