Land use controls soil bacterial diversity in the dry-hot valley region, Southern China

Soil microbial diversity is influenced by many factors, which are rarely studied together. To determine the dominant control on soil bacterial diversity in a typical dry-hot valley (DHV) of southwestern China, we collected soil samples in farmland, garden land and forestland along four elevation gradients of < 600, 600-700, 700-800, and > 800 m. Soil bacterial community abundance and composition was determined by high-throughput sequencing of 16S rDNA. The results showed that the dominant phyla in all soil samples were Proteobacteria, Actinobacteria, Firmicutes, chloroflexi and Acidobacteria. Soil bacterial absolute abundance in farmland was the greatest, followed by forestland and garden land. Differences in soil bacterial composition among three land uses were significant (p < 0.05) at elevations < 600 and 600-700 m. Four alpha-diversity indices (Shannon, Simpson, ACE and chao1) of soil bacteria in forestland and farmland showed insignificant differences among elevation gradients. Redundancy analysis indicated that land use was the dominant control on soil bacteria diversity, implying that shifts in land use could impact soil microbial diversity.