CONCLUSION
Nine years of N and P additions to alpine meadows differentially affected the magnitude and direction of PEs and SOC decomposition (except with vanillin amendment under N addition), accelerated substrates (glucose and vanillin) mineralization and but decreased the microbial CUE. This was mainly associated with the differences in soil and microbial C:N:P stoichiometric ratios, and substrates decomposability due to N and P additions. These changes indicated that long-term N and P additions resulted in greater losses of both easily degraded C and recalcitrant organic C by microbial respiration and led to lower C accumulation, thereby lower SOC content in the topsoil compared with Control, in particular P addition (Figure 5). Therefore N and P additions would weaken the soil functioning as a C pool of alpine meadows.