摘要：Soil water content (SWC) regulation on the responses of soil respiration ( R s ), autotrophic respiration ( R a ), and heterotrophic respiration ( R h ) to warming are rarely investigated in alpine meadow ecosystem in the Qinghai-Tibet Plateau (QTP). We conducted a warming experiment to investigate how SWC regulates the responses of R s and its components ( R a and R h ) to warming. Infrared heaters were used to simulate climatic warming. Soil respiration was measured inside surface collars (2–3 cm deep) and R h was measured inside deep collars (50 cm deep), which excludes root respiration. Autotrophic respiration was calculated by subtracting R h from R s . Warming increased the average R s and R h by 9.9% and 12.7% but had no significant effect on R a . Interaction between warming and SWC had significant effect on R s and its components. Soil respiration and R a decreased by 5.8% and 36.3% in dry conditions, but they increased by 23.5% and 47.7% in wet conditions. Growing season above-ground biomass was enhanced by 0.1 kg m -2 in wet conditions but reduced by 0.10 kg m -2 in dry conditions under warming manipulation. The estimated net ecosystem carbon (C) balance was 0.65 and -0.16 kg m -2 in wet and dry conditions, respectively, which indicates a net C emission of alpine meadow in wet but a net C sequestration in dry conditions. Our results emphasize the importance of incorporating SWC in simulation of ecosystem carbon balance under a warming climate.
