基于GIS和RUSLE的高山峡谷区土壤侵蚀研究——以云南省泸水县为例

目的]研究区域土壤侵蚀,揭示水土流失的空间分异规律,为区域水土保持和生态农业建设提供理论指导依据。方法]应用GIS和RUSLE模型对云南省泸水县的土壤侵蚀进行研究。RUSLE模型中的因子包括降雨侵蚀力、土壤可蚀性、坡度坡长因子、植被覆盖和水土保持措施因子,运用GIS空间分析模块,获取泸水县土壤侵蚀模数空间分布图,根据SL 190-2007的分级标准进行土壤侵蚀强度分级,并分析该区土壤侵蚀强度空间分布格局。结果](1)从各强度侵蚀面积上看,泸水县2014年土壤侵蚀以微度侵蚀为主,占总面积的86.86%,但从平均土壤侵蚀模数看,土壤侵蚀量为4.24×10~6 t,平均侵蚀模数为1 373.1t/(km~2·a),土壤侵蚀强度属于轻度侵蚀;(2)土壤侵蚀较严重区与未利用地、耕地空间分布基本一致,在坡度25°~50°的范围内,侵蚀面积占总侵蚀面积的75%,并且在该坡度段上的耕地面积占总耕地的63%,剧烈侵蚀集中分布在未利用地上,中度以上剧烈以下强度侵蚀集中分布在该坡度段上的耕地上,说明该坡耕地、未利用地对土壤侵蚀的贡献最大,要加强对未利用地的生态治理。结论]坡度大,陡坡垦殖和未利用地的不合理利用是该区土壤侵蚀加重的主要原因,坡度在25°以上的地区不适宜耕种,应优化农业产业结构如实施退耕还林还草等措施,才能有效的保持水土。

A Study on Soil Erosion in Alpine and Gorge Region Based on GIS and RUSLE Model- Taking Lushui County of Yunnan Province as an Example

Objective] To research regional soil erosion and reveal the spatial distribution of soil and water loss in order to provide theoretical support for regional soil and water conservation and eco-agriculture construction.Methods] Soil erosion in Lushui County of Yunnan Province was studied by using GIS and RUSLE model. The factors in the RUSLE model included rainfall erosivity, soil erodibility and slope and length, vegetation cover and soil maintain measures factors. Spatial distribution map of soil erosion modulus in Lushui County was obtained by using GIS spatial analysis module. The soil erosion intensity was classified according to the grading standards of SL 190-2007, and the spatial distribution pattern of soil erosion intensity was analyzed.Results] (1) According to the area, soil erosion intensity in Lushui County in 2014 was mainly micro degree of erosion, which accounted for 86.86% of the total area. While according to the average soil erosion modulus, soil erosion amount was 4.24×10⁶ t, the average erosion modulus was 1 373.1 t/(km²·a), and the soil erosion intensity was mainly slight erosion. (2) Soil erosion in the unused land and cultivated land was more severer. The erosion area in the slope between 25° and 50° was accounted for 75% of the total erosion area, in which the cultivated land accounted for 63%. Moderate and intensive erosion distributed mainly on the cultivated land, indicated that the slope farmland and unused land contributed the most to soil erosion.Conclusion] The steep slope, cultivation and unreasonable use of unused land are the main causes for the severer soil erosion in the study area. It is not suitable for cultivation in the slope above 25°. To maintain soil and water, we should optimize the agricultural industrial structure.