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针对京津水源区生态环境脆弱,水土流失空间分异大,突发性强等问题,选择河北省滦平县西北沟小流域为研究对象,利用气候、土壤、地形、土地利用及植被盖度等数据,运用GIS和RUSLE的方法对小流域土壤侵蚀强度及其空间分异特征进行了研究。结果表明,流域多年平均侵蚀模数为3 816.835t/(km2.a),属中度侵蚀;潜在侵蚀模数为31 583.150t/(km2.a),是现实侵蚀模数的8.28倍;不同土地利用方式中,零星分布的大坡度坡耕地侵蚀强度最大,其次为高度风化,坡度较大的退化荒草地,退化荒草地面积占流域总面积的59.38%,侵蚀量占总量的88.48%,是最主要的泥沙来源地;不同坡度土壤侵蚀强度随坡度加大而显著增加,流域坡度>25°的面积约占流域总面积的1/3,侵蚀量约占2/3;不同坡向的土壤侵蚀空间分异也十分明显,表现为正阳坡>半阳坡>半阴坡>正阴坡>平地。
In view of the fragile ecological environment in Jing-Jin water source area, the large spatial heterogeneity of soil and water loss and sudden emergencies, this paper selected the small watershed of Xibeigou, Luanping County, Hebei Province as the research object, and took advantage of climate, soil, topography, land use and vegetation cover And other data, using GIS and RUSLE method to study soil erosion intensity and spatial differentiation characteristics of small watershed. The results show that the average erosion modulus of the basin is 3 816.835t / (km2.a) for many years, which belongs to moderate erosion; the potential erosion modulus is 31 583.150t / (km2.a), which is 8.28 times of the actual erosion modulus; In the land use pattern, the erosion intensity of sporadic slope was the largest, followed by the degraded grassland with high degree of weed and slope. The area of degenerated grassland accounted for 59.38% of the total basin area and the erosion amount accounted for 88.48% of the total. Is the main source of sediment; soil erosion intensity of different slopes increases significantly with the increase of slope, the basin slope area> 25 ° accounts for about 1/3 of the total basin area, erosion accounts for about 2/3; Spatial heterogeneity of soil erosion is also very obvious, showing positive positive slope> semi-sunny slope> semi-shady slope> positive shady slope> flatland.