黄土高原小流域景观格局对土壤侵蚀的影响——以黄家二岔流域为例

The Effect of Landscape Pattern on Soil Erosion in Loess Plateau Catchment——Take Huangjia Ercha Catchment as an Example

以黄家二岔流域为例,分析该区的景观格局,选取斑块大小、斑块破碎度、等高连通度、顺坡连通度和斑块相对位置指数5个指标对景观格局进行量化,再结合地形,将该流域分为阴坡和阳坡分别计算它们的景观格局,并分析它们与土壤侵蚀的关系.最后得到,黄家二岔流域主要土地利用类型为耕地和人工草地,其中阳坡以人工草地为主,其斑块较完整,等高连通度大,斑块排列顺序也利于保持水土;而阴坡以耕地为主,斑块完整,顺坡连通度大,斑块排列顺序不利于水土保持.因此阳坡景观格局利于保持水土,而阴坡景观格局利于土壤侵蚀.

In the catchments of Loess Plateau, the landscape pattern has been formed mainly by human activities. So the land use is the key factor of landscape patterns. It is very valuable to pay attention to the effect of landscape patterns on soil erosion. The paper takes the Huangjia Ercha catchment as an example, analyses its landscape patterns in several parts: the patch's area, the patch's pattern direction and the patch's arrange order. We select the patch's area rate and the patch's fragment extent to show the patch's area; Select the connection extent along the contour and the connection extent along the slope to show the patch's pattern direction; Select the patch's relative position to show the patch's arrange order. Combining the landform, we divide the catchment into two parts: the sun slope and the shade slope.Then we calculate their landscape pattern factors, analyze the effect of landscape on soil erosion. The results show that: artificial grassland is the main land use type, the rate of tilth is little in sun slope, artificial grassland is connected well along the contour. The landscape pattern in sun slope is in favour of soil and water conservation. But in the shade slope, tilth is the main land use type, the tilth is connected well along slope, and the landscape pattern can aggravate soil erosion. So soil erosion is more intense in the shade slope than that in the sun slope.