[Research and prospects for response mechanisms of soil respiration to experimental warming]

Soil respiration (R_s) is the main efflux of carbon pool from soil to atmosphere. Increasing R_s caused by rising temperature can result in significant change in the global carbon balance. Global mean land-surface temperature is predicted to rise by 0.3-4.8 ℃ by the end of 21 century. Therefore, how R_s responds to simulated experimental warming in the natural field is one of the critical issues in global change research. Here, we reviewed the response characteristics of R_s to simulated warming under different temporal and spatial patterns. Experimental warming can increase R_s at the short time scale, but there was no uniform law in the long-term warming experiments, and there were differences among different ecosystems. This paper also reviewed the mechanism underlying the simulated warming response of R_s. Warming can directly affect R_s, and warming can also affect R_s indirectly by affecting the environmental factors (e.g., soil water, soil salt, soil physical and che-mical properties), and the regulation of biological factors (e.g., photosynthesis, litter decomposition). Furthermore, we synthesized the formation mechanism of adaptability of R_s to warming, including adaptability of microbes, roots and enzymes to warming, water restriction, and regulation by excessive nitrogen and the substrate supply. Finally, the future research directions were proposed. The study of micro-ecosystem of rhizosphere, characteristics and mechanism of R_s under asymmetric warming should be strengthened. Also, more attention should be paid to the measurement of R_s in typical phenological periods and typical weather in different seasons. The research network of R_s response to simulated warming should be constructed for networking test.