Temperature sensitivity of soil respiration is affected by prevailing climatic conditions and soil organic carbon content: A trans-China based case study

Understanding the spatial variation of temperature sensitivity (i.e. Q10) of soil respiration (Rs) and its controlling factors, is critical to improve the precision of carbon budget estimations at regional scales. In this study, data from 2–3 continuous years of Rs measurements over 15 ecosystems of ChinaFLUX were summarized to analyze the response of Rs to soil temperature. Moreover, we improved our dataset by collecting previously published Q10 values from 34 ecosystems in China. The ecosystems studied were located in the main climatic zones of China, spanning from alpine via temperate to tropical. Spatial variations of Q10 and its controlling factors were analyzed. The results showed that soil temperature at a 5 cm depth satisfactorily explained the seasonal variations in Rs of the 15 ChinaFLUX ecosystems (R2 varying from 0.37 to 0.83). Based on the overall data, the Q10 values of Rs in China ranged from 1.28 to 4.75. The spatial variations in Q10 were primarily determined by soil temperature during measurement periods, soil organic carbon (SOC) content, and ecosystem type. Ecosystems in colder regions and with higher SOC content had relatively higher Q10 values. Moreover, ecosystems of different vegetation types showed different Q10 values. A temperature- and SOC-dependent function for Q10 is suggested, which could be a valuable reference for improving the regional-scale models of Rs and ecosystem carbon cycles.