Abstract: To reveal the relationship between saline-meadow plant communities and,soil matrix and salinity,we selected saline meadow communities and soil of the Ordos Plateau as research objects. According to the classification of "Chinese Vegetation",we divided the studyarea into salt marsh bare land (Ⅰ),succulent and salt-tolerant plant meadow (Ⅱ),carex meadow (Ⅲ),grass meadow (Ⅳ) and weed meadow (Ⅴ) analyzed plant diversity index,soil texture and salinity characteristics and their relationships. The results showed that the overall plant diversity index in the study area was low,and there were significant differences among the fourtypes of meadows under different salinity levels (P<0.05). The mechanical composition of the soil in the study area was mainly clay and fine sand;soil of Ⅱ was relatively fine;soil of Ⅲ was thicker,which may have stronger hidden dangers of desertification. The surface layer of the four types of meadow soil was finer,and the vegetation can intercept wind and sand. The study areas were all saline-alkaline soil,Ⅰsoil had extremely high salinity and had no plants survived;Ⅱsoil was partially saline soil;Ⅲ,Ⅳ and Ⅴ belonged to partial alkaline soil. Soil salinity was the main influencing factor of plant community changes (P<0.01),soil pH was significantly negatively correlated with total salt content(P<0.05),and had an indirect influence. Soil particles affected each other,but had no significant correlation with salinity.

Key words: Halophyte, Plant diversity, Soil texture, Salinity characteristics, Soil profile

摘要： 为揭示盐生草甸植物群落类型与土壤基质和盐分的关系，本研究选取鄂尔多斯高原盐生草甸群落及土壤为研究对象，按照《中国植被》分类法，将研究区划为盐沼裸地（Ⅰ）、肉质耐盐植物草甸（Ⅱ）、苔草草甸（Ⅲ）、禾草草甸（Ⅳ）和杂类草草甸（Ⅴ），分析它们的植物多样性指数、土壤质地和盐分特征以及它们之间的关系。结果显示：研究区植物多样性指数整体较低，不同盐碱程度下4类草甸存在显著差异（P<0.05）。研究区的土壤机械组成以粘粒和细砂粒为主；Ⅱ土质相对较细腻；Ⅲ土质较粗，可能存在更强的沙漠化隐患；4类草甸土壤的表层较细，植被对风沙有截留作用。研究区均属于盐碱土，Ⅰ土壤盐碱度极高，无植物生存；Ⅱ土壤属于偏盐土；Ⅲ，Ⅳ和Ⅴ属于偏碱土。土壤盐分是植物群落变化的主要影响因子（P<0.01），土壤pH与全盐含量显著负相关（P<0.05），具有间接影响；土壤各颗粒物之间相互影响，但与盐碱度无显著相关性。

关键词: 盐生草甸, 植物多样性, 土壤质地, 盐分特征, 土层剖面