Abstract: In order to analyze the carbon (C),nitrogen (N) and phosphorus (P) contents and their stoichiometric characteristics of different plant communities and soil in Ningxia desert steppe region,eight plant communities in the desert steppe region of Yanchi County were studied,the purpose is to clarify the nutrient cycling and limitation of dominant plant and soil. The main results were as follows:Compared with the global average level,the contents of C,N and P in the dominant plant leaves and soil of different communities in the study area were lower,and the ecostoichiometric characteristics of the dominant plants in different communities were different;P was the main limiting factor of plant growth in the Sophora alopecuroides community,Stipa breviflora community,Leymus secalinus community and Nitraria tangutorum community;N was the main limiting factor for the growth of plant leaves in the Glycyrrhiza uralensis community,Pennisetum centrasiaticum community and Artemisia ordosica community;N and P were the limiting factors in the Lespedeza potaninii community;soil C content was significantly positively correlated with plant C content (P<0.01),positively correlated with soil N and P contents (P<0.05);and plant C contents was significantly positively correlated with soil P contents (P<0.05).

Key words: Yanchi County,Ningxia, Desert steppe, Plant community, Dominant plant, Soil, Ecological stoichiometry

摘要： 为分析宁夏荒漠草原区不同群落植物与土壤的碳（Carbon，C）、氮（Nitrogen，N）、磷（Phosphorus，P）含量及其比值特征，本研究以宁夏盐池县荒漠草原区8种群落的植被及土壤为对象，研究了不同群落优势植物与土壤生态化学计量特征及其相互关系。结果表明：与全球平均水平相比，研究区不同群落优势植物叶片与土壤的C，N，P含量均较低；不同群落优势植物叶片与土壤的生态化学计量特征不同；苦豆子（Sophora alopecuroides）群落、短花针茅（Stipa breviflora）群落、赖草（Leymus secalinus）群落与白刺（Nitraria tangutorum）群落的限制植物生长的元素主要是P，甘草（Glycrrhiza uralensis）群落、中亚白草（Pennisetum centrasiaticum）群落和油蒿（Artemisia ordosica）群落植物的生长限制元素主要是N，N与P元素共同限制牛枝子（Lespedeza potaninii）群落的植物生长；土壤总C含量与植物总C含量具有极显著的正相关关系（P<0.01），与土壤全N和全P含量呈显著正相关（P<0.05）；植物总C含量与土壤全P含量呈显著正相关（P<0.05）。

关键词: 宁夏盐池县, 荒漠草原, 植物群落, 优势植物, 土壤, 生态化学计量