Effects of precipitation changes and warming on vegetation–soil–microbial relationships in desert grasslands

Vegetation–soil–microbial relationships significantly affect global climatic and environmental changes. Fluctuations in temperature and precipitation caused by climate change are the driving forces of dynamic changes in vegetation–soil–microbial relationships. Our study was conducted in the desert grassland of Ningxia, China, and involved five levels of annual precipitation (33 % (R33), 66 % (R66), 100 % (RCK), 133 % (R133), and 166 % (R166)) and two temperature levels (within and outside the open-top chamber). Our objective was to determine how vegetation–soil–microbial relationships in desert grasslands respond to changes in precipitation and warming. Our results showed that precipitation was positively correlated with above-ground living and root biomass, and soil organic carbon. R166 had the strongest effect on the correlation between vegetation, soil, and microbes, whereas R33 had the weakest effect. Temperature was positively correlated with soil microbial α- diversity, and the effect of warming on the correlation among vegetation, soil, and microbes was less significant than under natural temperature. The combination of precipitation and warming was positively correlated with the above-ground living biomass and soil respiration. The correlation effects of the combination of precipitation and warming on vegetation, soil, and microbes were more substantial than those of precipitation and warming. Our findings provide a theoretical basis for the formulation of reasonable response strategies for desert steppe ecosystems.