Meta-analysis of the Factors Affecting Soil Respiration Temperature Sensitivity Based on Indoor Measurements

In this study, we collected research findings in correlative field at a global scale over the past 15 years based on the meta-analysis method, and soil respiration temperature sensitivity(Q₁₀) database was established. The obtained environment factor variables including: initial temperature, temperature increase content, incubation time, soil moisture content, soil organic matter content, soil nitrogen content, soil pH value, average annual temperature, average annual precipitation, altitude, latitude and ecosystem classification. In this paper, we focus on the Q₁₀ variation at different ecosystem and the extent of Q₁₀ influenced by the different environment factor variables. A comprehensive analysis has been made through the linear mixed model and random forest regression, the result shows that there are significant differences in Q₁₀ values among different ecosystems(P < 0.05), and the mean value of global soil respiration Q₁₀ is 1.92. The average values of Q₁₀ in different ecosystems are: forest (1.70), meadow (1.88), farmland (2.79), wetland (1.53), desert (2.18), polar region (2.02). The initial temperature, temperature increase range, temperature increase time, soil moisture content, soil pH and annual average temperature have significant effects on Q₁₀(P<0.05). Among them, Q₁₀ decreases with the increase of the initial temperature; when the temperature increase is large, the value of Q₁₀ is small; Q₁₀ increases first and then decreases with the increase of the temperature increase; soil moisture content, soil pH and annual average temperature have a positive effect on Q₁₀. The effects of different environmental factors on Q₁₀ is initial temperature > soil pH value > temperature increase content > soil moisture content > latitude > soil organic matter content > altitude > soil nitrogen content > annual average precipitation > annual average temperature > incubation time. It is noted that the initial temperature and soil pH content are the main driving factors of Q₁₀, the contributions to Q₁₀ change is 20.6% and 19.9%, respectively. This study can provide reference for further exploration of soil respiration under climate change.