中文摘要：

对黄土丘陵区典型草原带宁夏云雾山自然保护区不同演替阶段植被下土壤的发生特性及系统分类进行了研究。结果表明：保护区内土壤保持有完整的发生层次，有明显的A层、过渡层（AB）、淀积层（B）与母质层（C）；土壤颜色、结构和养分在剖面层次上明显差异；土壤有机质含量较高，最高可达到31．5g·kg^-1；土壤碳酸钙有明显的淋溶淀积，在剖面中下部形成淀积层；颗粒组成以0．05—0．01mm粒级的细砂粒为主，其次为〈0．002mm的粘粒；土体矿质全量中，SiO2占绝对优势，Al2O3次之，化学元素的含量顺序依次为Si〉Al〉Ca〉Fe〉K≈Mg〉Ti〉Mn。土壤发育处于物理风化为主阶段，化学风化较为微弱，矿质元素的移动不明显。供试土壤共分属2个土纲，2个亚纲，3个土类和3个亚类，其中YW-2、4属于钙积暗厚干润均腐土，YW-3、5属于普通简育干润雏形土，YW-6属于钙积暗沃干润雏形土。

英文摘要：

In this article, matter composition, soil physical and chemical characteristics and structures are analyzed for studying the soil characteristics in Yunwu mountain natural conservation area of Ningxia province. The results show that there are some integrated soil mass configuration in all soil profiles, including A horizon, intergrading horizon （AB） , sediment horizon （B） and material horizon （C）. It is obviously different in soil color, nutrient and structure among the soil horizon. The highest content of organic matter in upper soil layer is 34.7g·kg^-1 The CaCO3 content of surface laver is less than that of the other layer and decreasing gradually. In the particle composition, the sand （0.05 -0.01 mm） content is the highest, clay（ 〈0. 001mm） secondly, silt lowest. There is weak leaching of clay and leaching layer of CaCO3 is deeper than clay layer. The main mineral element is SiO2, Al2O3 in soil, and the contents of them are more than 75% of total mineral. The contents of Ca, Fe, Mg, Ti and Mn etc. Decrease orderly. Soil main formation progress is in the stage of physical weathering. Matter leaching and chemical weathering are weak. The main mineral element moving is less obviously. The soils belong to 2 soil class, 2 subclass,3 soil great group and subgroup. Key words： Soil genesis properties; Taxonomic classification; Yunwu mountain area