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Fencing for grazing exclusion has been widely found to have an impact on grassland soil organic carbon (SOC) and total nitrogen (TN), but little is known about the impact of fenced grassland on the changes in deep soil carbon (C) and nitrogen (N) stocks in temperate grasslands. We studied the influence of 30 years fencing on vegetation and deep soil characteristics (0–500 cm) in the semi-arid grasslands of northern China. The results showed that fencing significantly increased the aboveground biomass (AGB), litter biomass (LB), total biomass, vegetation coverage and height, and soil water content and the SOC and TN in the deep soil. The belowground biomass (BGB) did not significantly differ between the fenced and grazed grassland. However, fencing significantly decreased the root/shoot ratio, forbs biomass, pH, and soil bulk density. Meanwhile, fencing has significantly increased the C and N stocks in the AGB and LB but not in the BGB. After 30 years of fencing, the C and N stocks significantly increased in the 0–500 cm soil layer. The accumulation of SOC mainly occurred in the deep layers (30–180 cm), and the accumulation of TN occurred in the soil layers of 0 to 60 cm and 160 to 500 cm. Our results indicate that fencing is an effective way to improve deep soil C and N stocks in temperate grassland of northwest China. There were large C and N stocks in the soil layers of 100 to 500 cm in the fenced grasslands, and their dynamics should not be ignored. [ABSTRACT FROM AUTHOR]

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. • Ecological responses of desert-steppe SR to temperature increases and precipitation changes along with their ecological sensitivity indexes. • Correlations between SR, soil temperatures, soil moisture, and other soil properties and plant biomass in the desert grasslands. • This research provides a reliable theoretical basis for formulating a reasonable response strategy for desert steppes. [ABSTRACT FROM AUTHOR]