氮、磷添加对亚高寒草甸土壤及六种优势植物化学计量学特征的影响

Fertilization could increase the net primary production of plant and enhance the input of SOC,it could also change the Ecological stoichiometry characteristics of plant and soil. In this study, we investigated the efffects of N and N+P fertilization on Ecological stoichiometry characteristics in six species and soil at the rate of 5, 10, and 15 g m?2 yr?1 （N5、N10、N15、N5P5、N10P10、N15P15）compared to the unfertilized control treatment. The results showed that fertilization significantly decreased the soil organic carbon(SOC) content, the treatments of N+P significantly decreased soil C/P (except N10) and soil C/N; Besides, the treatments of N+P significantly increased the total P content in five non-legume species, and significantly decreased their C/P and N/P; The treatment of N15 significantly increased the N/P in five non-legume species but decreased C/N in two grasses compared to the control treatment; In all of the treatments, the C/N in two grasses was higher compared to the three forbs, and the C/P in two grass species was also higher than the three forbs (except N5 and N10). In conclusion, single N fertilization at high rate (N15) could alleviate N contraintst, while the treatments of N+P could aggravate the N contraints. Because of lowered soil C/N, fertilization is not conducive to SOC accumulation in this area.