Effects of increasing precipitation on soil microbial community composition and soil respiration in a temperate desert, Northwestern China

Soil microbial communities play a critical role in soil carbon cycling and influence soil carbon-climate feedbacks. However, little information exists regarding the response of soil microbial communities in temperate desert ecosystems to projected increases in precipitation and the resulting effects on soil carbon emissions. A three-year precipitation addition experiment was conducted to explore the responses of soil respiration (Rs), microbial respiration (Rm) and microbial community composition to low (extra 15%) and medium (extra 30%) precipitation increases in a temperate desert ecosystem. Rs, Rm, microbial biomass carbon (MBC) and nitrogen (MBN), and microbial PLFAs consistently increased with increasing precipitation. Rs and Rm were positively correlated with MBC and microbial PLFAs. However, precipitation addition had no impacts on microbial community composition and fungal to bacterial PLFAs ratio. These results suggest that projected precipitation increase may synergistically increase bacterial and fungal abundance, and stimulation of microbial biomass can increase soil carbon release in desert ecosystems.