宁强县土壤侵蚀的地貌分布特征

为了揭示宁强县土壤侵蚀的空间分布特征,利用GIS技术,通过对宁强县土壤侵蚀强度分布图和DEM图的叠加,得到土壤侵蚀强度在坡度、坡向、高程、起伏度等地貌因子的分布特征。结果显示,宁强县水土流失程度为63.79%,土壤侵蚀强度以中度为主。不同坡度、高程、起伏度下的水土流失面积比例、土壤侵蚀综合指数和土壤侵蚀强度分别随着坡度增加、高程升高、起伏度上升呈先增大后减小的单峰分布趋势。平地的水土流失面积比例接近0,不同坡向的水土流失面积比例、土壤侵蚀综合指数和土壤侵蚀强度分布差异不显著。不同土壤侵蚀强度的最大值和分布范围均随着坡度的增加而增大,但却随着高程的升高而减小。各土壤侵蚀强度的起伏度分布均很相似。此结论可为区域水土保持规划和水土流失治理提供决策依据和理论支持。

Landform distribution features of soil erosion in Ningqiang county

In order to reveal the spatial distribution features of soil erosion in Ningqiang county, the GIS technology was used to obtain the landform features in the respects of slope degree, slope direction, elevation and rolling degree of soil erosion distribution via overlap of the distribution map of soil erosion intensity in Ningqiang county and the landform element maps extracted from the digital elevation model. The results showed that the degree of soil erosion and water loss in Ningqiang county was 63.79%. The soil erosion intensity was mainly moderate. The distributions of soil erosion area percentage, soil erosion comprehensive index and soil erosion intensity at different slope degree, elevation and rolling degree were assumed as single peak. The soil erosion area percentage of flatland was close to 0. The distributions of soil erosion area percentage, soil erosion comprehensive index and soil erosion intensity at different slope directions were not different dramatically. The maximum and main range of different soil erosion intensity distribution were increased with rise of slope degree, but decreased with rise of elevation. The distributions of soil erosion intensity in different rolling degrees were similar. The results can provide a basis for decision making and theory support for making regional plan of soil and water conservation and treatment of soil erosion and water loss.