基于GIS与RUSLE的武陵山区小流域土壤侵蚀评价研究

SOIL EROSION EVALUATION OF SMALL WATERSHED IN WULING MOUNTAIN BASED ON GIS AND RUSLE

以长江中下游武陵山区女儿寨小流域为研究区,基于数据观测积累及实地调查采样等方法,计算了研究区降雨侵蚀力、土壤可蚀性等因子,运用GIS与RUSLE评价了流域土壤侵蚀强度并分析了其与土地利用方式、海拔高度的关系。结果表明,流域平均土壤侵蚀强度为788.44t/(km2.a),属微度侵蚀,流域面积95.18%的范围发生轻度以下的侵蚀,强烈以上侵蚀仅占1.19%。从土地利用类型来看,耕地、果园侵蚀强度较大,均达到中度侵蚀,有林地除竹林地为轻度侵蚀外均属微度侵蚀,耕地、果园、竹林地是今后水土流失防治的主要地类。不同海拔高度中,低海拔(200～400m)区域侵蚀量占到流域侵蚀总量的64.42%,是水土流失防治的重点地带。研究为应用修正通用土壤流失方程在武陵山区进行土壤侵蚀评价提供范例,为研究区防治土壤侵蚀和流域管理规划决策提供相应参考。

Taking Nüerzhai small watershed which lies in Wuling Mountain of middle-lower Yangtze River as study area,this paper calculated some factors such as rainfall erosivity and soil erodibility based on data observed and sampling on the spot in watershed.By using geographic information system（GIS）and the revised universal soil loss equation（RUSLE）,the soil erosion intensity and its relationship with land use types and altitudes in watershed were studied.The results show that the average soil erosion intensity in the watershed was 788.44 t/（km2·a）,which was in the category of feeble degree erosion.95.18% of watershed was below the category of slight degree erosion and only 1.19% of watershed exceeded the category of strong degree erosion.In different land use types,soil erosion intensities of cultivated land and orchard were bigger than the others.They were in the category of moderate degree erosion.Forest land was in the category of feeble degree erosion except for bamboo grove,which was in the category of slight degree erosion.Cultivated land,orchard and bamboo grove were the main land use type for preventing soil and water loss in future.In different altitudes,64.42% of the total soil loss occured in lower altitudes（200~400 m）.This region was the major region for preventing soil and water loss.The study provides an example for applying RUSLE to assess soil erosion in Wuling Mountain area and offers useful references for preventing soil erosion and making decision for watershed management.