基于GIS的农林复合经营的侵蚀控制模拟研究

Study on the GIS-based Simulation of Erosion Control for Agroforestry

根据张家口郭家梁试验场的小区资料 ,建立了小流域侵蚀产沙模型以及植物篱侵蚀控制模型 ;并在 GIS的支持下 ,从小流域数字高程模型 (DEM)中提取基于地块间水沙汇流网络 ,生成基于地块的水沙运移网络图 ,并将地块间的水沙汇流过程引入小流域侵蚀产沙的模拟中 ,实现了侵蚀产沙模型与地理信息系统 (GIS)的深层次耦合 ,模拟出坡面水沙在小流域的空间运动过程。 1995～ 1999年的青边口河小流域模拟结果表明 :坡耕地、荒坡地、低覆盖的天然草地的平均侵蚀模数最大 ,是侵蚀控制的重点土地利用类型。在坡耕地、荒坡地、低覆盖的天然草地配置面积占流域总面积的 18.2 %的植物篱 -农作系统 (10 m带间距的二年生紫穗槐植物篱 ) ,利用次降雨资料的计算模拟结果表明 ,对径流的控制效果在 8.1%～ 46 .2 %之间 ,对侵蚀模数的控制效果在 42 .9%～ 5 0 .2 %之间 ;养分流失的模拟分析表明 ,在现有条件下有机质的损失较大 ,而通过配置植物篱

Based on the data of Guojialiang test site, soil erosion and sediment yield models and erosion control models of the hedgerow were established. The study produced water and sediment transport networks of the catchment from digital elevation model (DEM) and brought them to the models. The combination of GIS and models simulated the influence of upper runoff to the lower slope and the spatial process of runoff and sediment transport in a catchment. The result of the simulation from 1995 to 1999 showed that cultivated slope land, bare slope land and natural grass land with low vegetative cover have the highest erosion modulus in Qingbiankohe catchment, and they are the important regions for erosion control. Authors simulated the system of the hedgerow-crops in these regions whose area only has 18.2% of the whole catchment. The results show that the control effect for runoff is between 8% and 46% and the control effect for sediment is between 42% and 50%. The simulation results of nutrient loss shows that the loss of organic matter is severe on current conditions. However, it is an effective method to control the nutrient loss on the condition of hedgerow-crops system.