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Purpose: The purposes of this study are to characterize the relationship between basal soil respiration at 0 °C (R0) and the temperature sensitivity (Q10) of soil respiration and climate, soil, and vegetation factors and to establish R0 and Q10 models. Materials and methods: We compiled R0 and Q10 and variables (i.e., climate factors, soil properties, and vegetation characteristics) that were measured in various terrestrial ecosystems. Results and discussion: The results showed that both R0 and Q10 could generally be fitted by a normal distribution curve across various ecosystems, but they varied greatly among the different ecosystems. The lowest median R0 and Q10 appeared in the desert, while the highest median R0 and Q10 appeared in the deciduous broad-leaf forest and deciduous needle-leaf forest ecosystems, respectively. The relationship between R0 and Q10 across different soil depths varied among the different ecosystems, with the highest and lowest R2 occurring in the cropland (R2 = 0.701) and evergreen needle-leaf forest (R2 = 0.095), respectively. A model that included Q10, fine root production and the ratio of soil organic carbon to total nitrogen (TN) explained 75.0% (R2 = 0.750) of the variation in R0, with a P value less than 0.001. Q10 was further expressed as a model (R2 = 0.663, P < 0.001) including annual precipitation, mean air temperature, TN, bulk density, and leaf area index. Conclusions: Our R0 models can potentially be used to improve terrestrial carbon cycle models by considering the comprehensive effects of Q10 and soil and vegetation factors. [ABSTRACT FROM AUTHOR]

Soil respiration ( Rs) is one of the key processes that underline our understanding of carbon cycle in terrestrial ecosystems. Great uncertainty remains in the previous global Rs estimates with a difference of 70 Pg C a −1 between the highest and lowest estimates. Thus, the present study aimed to estimate the global annual Rs and investigate the interannual and spatial variability in global annual Rs using a semi-mechanistic, empirically-based model which included climatic factors (temperature and precipitation) and topsoil (0–20 cm) organic carbon storage. About 657 published studies of annual Rs from 147 measurement sites were included in this meta-analysis. The global data sets from 1970 to 2008 on climate, surface air temperature, and soil properties were collected. The Monte Carlo method was used to propagate the simulation errors to global Rs. The results indicated that the mean annual global Rs was 94.4 Pg C a −1, increasing at roughly 0.04 Pg C a −1 (∼0.04% a −1) from 1970 to 2008. The Rs rate increased from colder, drier and less soil carbon-rich regions to warmer, moister and more carbon-rich regions. Highest Rs rates appeared in the tropical forest, while the lowest ones were in polar and desert regions. The annual Rs correlated directly with global temperature anomalies, suggesting that the interannual variability in temperature was responsible for the interannual variations in predicted global Rs. The global Rs increased from high-latitude zones to low-latitude zones. Further studies are recommended to explore the relationship between soil respiration and vegetation characters. [ABSTRACT FROM AUTHOR]