Variation of Q10 values in a fenced and a grazed grassland on the loess plateau, northwestern China

AbstractSoil respiration (SR) and microbial respiration (MR), which were primarily regulated by soil temperature, can act as a feedback to climate change. Although many studies suggest that global warming will accelerate carbon dioxide (CO2) emissions from soil, the magnitude of this feedback is unknown, mostly due to uncertainty in the temperature sensitivity (Q10, increaing ratio of SR and MR after a 10°C increase of temperature) of SR and MR. To investigate the seasonal variation of short-term Q10 and estimate how grazing impacts temperature sensitivity of SR and MR, we measured SR and MR in a fenced and a grazed grassland on the loess plateau, northwestern China, during 2008–2010. In this semiarid grassland ecosystem, soil temperature was the dominant factor controlling SR and MR during the experimental period. Short-term apparent Q10 of SR and MR had a clearly seasonal variation, and was significantly and negatively related to soil temperature at 2-cm depth. However, no relationship was found between...