Alkalinity gradients in grasslands alter soil bacterial community composition and function

Clarifying the bacterial community composition and function in alkali soils is pivotal to the soil capability of sustaining venerable ecosystems. Using MiSeq sequencing, PICRUSt, and Biolog (), we investigated the bacterial community composition and metabolic function of microbes in three soils differing in the severity of alkalinity. A high level of alkalinity deceased the diversity of microbial community and altered microbial community composition with the increase in relative abundances of 21 genera. The linear discriminate analysis and effect size analysis found most of 54 biomarkers belonged to Actinobacteria and Proteobacteria. Redundancy analysis indicated that the succession of bacterial community and metabolic characteristics of microbes were highly affected by the nutrient availability and soil moisture. The utilization rates of carbohydrates, amino acids, carboxylic acids, polymers, phenolic compound, and aminesides by microbes were positively correlated with soil nutrient concentrations but negatively correlated with the exchangeable sodium percentage and pH. Severe alkalinity inhibited the microbial community diversity and function on carbohydrate metabolisms.