密云水库上游不同土地利用方式下的土壤侵蚀特征

目的]为了合理配置北京密云水库水土流失重点治理区的水土保持综合措施。方法]基于石匣小流域坡面径流小区定位观测资料,分析了不同土地利用方式及水土保持措施的坡面土壤侵蚀特征。结果](1)5种土地利用方式的土壤侵蚀量差异明显,与裸地相比较,耕地、人工草地、封禁荒草地和林地的减沙率达63.88%~99.63%;(2)梯田比坡耕地措施小区的土壤侵蚀量减少了95.62%,起到了显著的水土保持作用;(3)采用水平条和鱼鳞坑措施林地小区的减沙率分别为83.56%和96.53%,具有十分明显的减蚀作用;(4)与人工草地相比较,封禁荒草地的侵蚀产沙量减少了98.25%,可以有效地控制水土流失。结论]增加地表植被覆盖,减少人为干扰以及合适地配置梯田、鱼鳞坑和水平条等水土保持工程措施具有良好的水土保持作用。

Characteristics of Soil Erosion Under Different Landuse Types in Upper Area of Miyun Reservoir

Objective] To configuring appropriate soil and water conservation measures for solving the problem of soil and water erosion in upper area of Miyun reservoir in Beijing City.Methods] Based on the data of 13 different runoff plots in Shixia small watershed, the effects of different land use types and soil conservation measures were analyzed.Results] Woodland was the most effective soil and water conservation measure at slope scale. The order of soil conservation benefits in five land use types was that:woodland> banned tending> artificial grassland> cropland> bare land, and the sediment was reduced by 63.88% to 99.63%. Compared with steep slope land, the sediments from terraces were reduced by 95.62%. Fish-scale pit and horizontal bars measures can effectively intercept surface runoff and control erosion.Conclusion] Through establishing the mixed structure stand and configuring soil and water conservation engineering measures, such as fish-scale pit terraces and level strips, soil and water loss can be effectively controlled.