Soil microbial communities and their relationships to soil properties at different depths in an alpine meadow and desert grassland in the Qilian mountain range of China

This study examined whether soil microbial composition would respond differently between alpine meadow and desert grasslands located in the Qilian mountain range in the semi-arid region of northwestern China. The measurements were carried out along a soil profile up to 40 cm. The total nitrogen (TN), total carbon (TC), soil organic carbon (SOC) and soil water content (SWC) were significantly higher (P-value < 0.05) in alpine meadow than in desert. In alpine meadows, all these properties decreased with increasing soil depth, and in desert grassland these properties - except SWC and TN - remained the same at all soil depths. The bacterial phyla Actinobacteria dominated both grasslands, significantly more so in desert grassland (P-value< 0.05). In alpine meadows Proteobacteria, Acidobacteria, Gemmatimonadetes, Planctomycetes and Rokubacteria abundance was significantly higher (P-value < 0.05). The distribution pattern of bacterial phyla along soil depth was different between the two grasslands. The abundance of Ascomycota and Basidiomycota was unaffected by grassland type or soil depth. Alpha and beta diversity analysis revealed two grasslands harbored distinct bacterial and fungal communities. We identified soil carbon, nitrogen and water as important factors that shaped the bacterial and fungal community in these semi-arid grasslands.