中文摘要：

以北京市延庆县上辛庄小流域为研究区域，选择区内农地、杏林、侧柏林、乔灌混交林这4种土地利用方式，通过对土壤水稳性团聚体特征、有机质含量变化以及土壤可蚀性K值进行计算和分析，研究了该区不同土地利用方式下的土壤可蚀性差异特征。结果表明，不同地类土壤团聚体破坏率表现为：农地〉杏林〉侧柏林〉乔灌混交林，林地土壤团聚体结构破坏率显著低于农地（p〈0．05）。农地土壤有机质含量随土层深度的增加呈现一定的上升趋势，林地的土壤有机质含量随土层深度的增加而减小。不同土地利用方式的土壤可蚀性K值存在差异，表现为：乔灌混交林〈侧柏林〈杏林〈农地。表层0-20cm土层土壤可蚀性K值小于20-40cm土层，表明其土壤抗侵蚀能力高于深层土壤，反映出保护表层土壤的重要性。对土壤可蚀性影响因子的分析结果表明，土壤黏粒含量、有机质含量和水稳性团聚体与土壤可蚀性K值的相关关系最为密切（p〈0．05）。

英文摘要：

The soil erodibility characteristics of four land use types in Yanqing County of Beijing City, such as agricultural land, Prunus armeniaca, Cupressacea, mixed forest of trees and shrubs, was studied by measur- ing and analyzing the characters of soil water-stable aggregates, organic matter content and the soil erodibili- ty K value. The results showed that structural damage rate was followed in the order： agricultural land〉 Prunus armeniaca〉Cupressacea〉mixed forest of trees and shrubs, and forestlands were significantly lower than agricultural land（p〈0.05）. Soil organic matter content with the increase of soil depth has certain rising trend in the agricultural land, soil organic matter content with the increase of soil depth decreases in the for- estlands. Different land use types have the K value differences, which was followed in the order： mixed for- est of trees and shrubs〈Cupressacea〈Prunus armeniaca〈agricuhural land. The K value of surface soil （0--20 cm） was less than that of 20--40 cm deep soil, indicating that the soil resistance to erosion capacity was above the deep soil and it is important to protect the surface soil. The soil erodibility K value was closed related to the factors： such as soil clay content, organic matter content and soil water-stable aggregatest closely（p〈0.05）.