荒漠草原植物-微生物-土壤C:N:P化学计量对氮磷添加的响应机制

C:N:P生态化学计量在植物-微生物-土壤系统中的变化格局及其相互作用研究，有助于深入认识荒漠草原生态系统C、N、P平衡及其内在稳定性维持机制。本项目通过荒漠草原N、P添加控制实验，以“植被-微生物-土壤”的协同响应为视角，以生态化学计量学为切入点，研究荒漠草原N、P添加对植物、土壤、土壤微生物和胞外酶C:N:P生态化学计量特征的影响，结合土壤微生物群落结构、元素比例阈值（TER）、土壤微生物碳素利用效率（CUE）和养分利用效率（NUE和PUE），探讨荒漠草原植物、土壤和土壤微生物量C:N:P生态化学计量的关系及土壤微生物对土壤养分有效性和C:N:P生态化学计量变异的适应机理。研究结果旨在揭示荒漠草原植物-微生物-土壤生态化学计量对N、P添加的响应机制，为深化认识退化荒漠草原生态系统恢复过程中植物-微生物-土壤C、N、P动态平衡与维持机制提供科学依据。

The maintaining mechanism of C, N, P nutrient balance and ecosystem stability of desert grassland would be reveal by the interaction and variation pattern of C:N:P stoichiometry in plant-microbe-soil system. However, the response mechanism of plant-microbial-soil C: N: P stoichiometry to nitrogen and phosphorus addition in desert grassland currently remained unclear. Therefore, this project will take the desert grassland which manipulated with nutrient addition of nitrogen (N), phosphorous (P) and nitrogen–phosphorous (NP) as the research objects in order to probe into the response mechanism of plant-microbial-soil C:N:P stoichiometry to nitrogen and phosphorus addition. Effects of nitrogen and phosphorus addition on the C:N:P stoichiometry of plant, soil, soil microbial biomass and extracellular enzyme in desert grassland will be systematically studied by the perspectives of the collaborative response of “plant-microbe-soil” and combined ecological stoichiometry. Moreover, soil microbial community structure, threshold elemental ratio (TER), carbon use efficiency (CUE) and nutrient use efficiency (NUE and PUE) of soil microbial will be analyzed to discuss the interaction among plant, soil and soil microbial biomass C:N:P stoichiometry, and adaptive mechanism of soil microbial to the variation of soil nutrient availability and soil C:N:P stoichiometry. Findings of this project will reveal the responses mechanism of plant-microbial-soil C:N:P stoichiometry to nitrogen and phosphorus addition, and provide a scientific basis for C, N, P dynamic balance and maintaining mechanism of plant-microbe-soil in desert grassland ecosystem restoration.