Effect of Temperature Increase on Dynamic Changes of Soil Respiration in Alpine Wetlands

Experiment was conducted to determine the soil respiration rate, the soil temperature in 5, 10, and 15 cm layers and soil water content of Kobresia humilis in the sample plot by LI-8100 automated soil CO₂ flux system (open path) from June 2016 to September 2017, so as to study the dynamic changes of soil respiration in alpine wetlands in the simulated temperature increase state, and to investigate the effects of temperature increase on soil respiration. It can be seen from the results that simulated temperature increase is beneficial to the increase of soil respiration rate, which is significantly different from the rates both in the natural state (CK) and in the temperature increase state (W) (P < 0.01); that the soil respiration rate is significantly correlated with the soil temperature and soil water content of each layer (P < 0.01). The temperature sensitivity values Q₁₀ in the natural state are larger than those in the temperature increase state, and the Q₁₀ value increases as the soil depth increases. However, soil respiration was jointly influenced by the soil temperature and soil water content and it decreased after 2 years. The temperature increase is helpful to the increase of above-ground and below-ground biomass, and has a significant effect on shallow underground biomass. When compared with no temperature increase, temperature increase is conducive to increase the soil organic matter content, and the difference decreases as the soil depth increases. The experiment results have shown that temperature increase for 2 consecutive years can promote soil respiration in alpine wetlands, and a warming environment is conducive to promoting soil carbon release.