In this study, we collected soil samples from four different arborcommunities and four herb communities, which represented two vegetation ecosystems in the northwest of the Loess Plateau. Our objectives were to determine the diversity of soil bacterial communities and the affecting factors with the method of 454 high-throughput pyrosequencing technology. The results showed that the structures of the microbial communities differed in terms of both the predominant phylum and the relative abundance of each phylum. At the phylum level, the dominant phyla were Proteobacteria, Actinobacteria, Acidobacteria, Chloroflexi and Planctomycetes. At the class level, Actinobacteria, α-Proteobacteria, Acidobacteria, β-Proteobacteria and Planctomycetacia were predominant. The relative abundance of Actinobacteria in grass vegetation ecosystem was more abundant than that in forest vegetation ecosystem. Proteobacteria in forest vegetation ecosystem were more abundant. Soil pH was significantly correlated with the relative abundance of Actinobacteria. Soil organic matter,soil total N and soil total P were the key factors affecting soil Proteobacteria. These results will provide useful information for the diversity of soil bacteria and guide the practice of vegetation restoration in the Loess Plateau.
Keywords: 454 high-throughput sequencing; Loess Plateau; different vegetation types; environment factors; soil bacteria.