长江上游部分地区土壤侵蚀与机制探讨

通过调查、定位与半定位观测,研究了长江上游不同地貌类型区的土壤侵蚀空间分布格局,以及各影响因子与土壤侵蚀间的关系。揭示了泥沙运行机制和水土流失规律,提出了小流域泥沙运移的输移比:流域面积小于5km~2,用0.6～0.7作为泥沙输移比;小于30km~2,用0.3～0.4作为输移比,推算流域土壤流失量,并建立了坡面和小流域土壤流失预报模型。

A Discussion on Soil Erosion and its Mechanism in Some Regions in the Upper Reaches of the Yangtze River

By means of investigations and permanent and semi-permanent observations, researches were directed toward the spatial distribution patterns of soil erosion in varied landforms in the upper reaches of the Yangtze River and toward the relations between influential factors and soil erosion. We discovered the silt transportation mechanism and the laws of soil and water loss,and put forward the transport ratio of silt in a watershed. When the area of a watershed is less than 5 km~2,0. 6-0. 7 should be used as the transport ratio of silt,and when the former is less than 30 km~2,0. 3-0. 4 should be used. As a result,the amount of soil loss in a watershed can be calculated and the soil loss prediction models of a slope or a watershed can be established.