Comparative Analysis of Soil Bacteria Assemblages Across Land-Use Types in a Given Karst Landscape in Southwest China

Land-use types have significant effects on soil microbial communities, yet few studies have compared soil bacteria assemblages in a given karst landscape with multiple land-uses. Consequently, soil samples from cornfields, grasslands, 10 year Eucalyptus forests and undisturbed rock covered soil were collected in triplicate from a given karst area in Southwest China to assess soil bacteria assemblages across land-use types using high-throughput sequencing of the V4-V5 region of the 16S ribosomal RNA gene coupled with soil chemical properties analysis. Our results indicated that soil organic carbon, total nitrogen, total phosphorus, and the exchangeable bases calcium and magnesium were all high in undisturbed rock covered soil and low in cornfields. Though the soil bacterial communities were different in the four land-use types, Acidobacteria, Proteobacteria, Chloroflexi, Actinobacteria, Firmicutes, Verrucomicrobia and Bacteroidetes dominated the soil bacteria communities across all of the soil samples. The soil properties had strong negative or positive correlations with the dominant bacterial phyla with land-use types. And, the gene groups of metabolism, genetic information processing, and environmental information processing with contrasting changes were dominating in grasslands, 10 year Eucalyptus forests and undisturbed rock covered soil. In particular, land-use type exerted significant direct effects on the soil bacterial composition and alpha diversity. Taken together, our findings revealed that land-use types affected soil bacteria assemblages across a given karst landscape in Southwest China.