The responses of soil respiration to changed precipitation and increased temperature in desert grassland in northern China

Soil respiration (SR) is an important process and the largest source of carbon cycle of terrestrial ecosystems, which has a significant impact on global climate and environmental changes. The fluctuation of temperature and precipitation caused by climate change is a driving force for the dynamic change of SR. Therefore, we established the field experiment with 5 levels of precipitation by rainout shelters and 2 levels of temperature by Open-top Chamber (OTC) to determine the SR dynamic in the desert grassland in northwest China. The results show that: soil temperature (ST) and soil moisture (SM) are affected by changed precipitation and increased temperature, but not greatly. Overall, it can be seen that the SR continue to increase with the precipitation increasing and the temperature rising. SR has no significant correlation with above-ground living biomass (ALB), but is significantly correlated with root biomass (RB), so SR mainly comes from the root system, and ALB and RB both increase with rainfall rising. Soil physical and chemical properties are related to SR, but not significantly. These findings provide a reliable theoretical basis for formulating a reasonable response strategy in desert steppe ecosystems.