长江三峡花岗岩区不同地类土壤流失量研究

 研究长江三峡库区泥沙来源,并以此为依据开展水土保持工作,对于保障长江三峡水利枢纽工程安全运行和效益发挥,具有重要意义。在长江三峡花岗岩地区选定的典型小流域内,采用土壤剖面法及土壤侵蚀调查、坡面径流小区等方法,分析不同土地利用现状下的土壤物理特性及其与土壤侵蚀的关系,不同土地利用坡面及沟道的土壤侵蚀量。结果表明:研究区域不同土地利用状况土体内,土壤颗粒特性与土壤流失程度密切相关。随着土壤流失程度的增大,流域不同土地利用状况下的A层土壤颗粒粒径分选系数降低。不同土地利用状况下,土壤颗粒粒径组的对称性均较低;长江三峡花岗岩区的泥沙,主要来源于坡面土壤侵蚀;坡面侵蚀的泥沙主要来源于坡耕地,25°以上陡坡耕地侵蚀的泥沙量,约占坡面产沙总量的50%。

Amount of Soil Loss Under Different Land Use Type in Granite Area of Three Gorges of Yangtze River

Research on the sediment sources in small watershed of Three Gorges Reservoir Area can guarantee hydro-junction engineering's safe working and benefit exertion. In the selected typical small watershed, several soil profiles were dug, and the relationship between physical characteristics of soil under different types of land utilization and soil erosion is analyzed through the investigation of soil erosion, the observation of sediment and runoff in slope plot. The quantity of soil erosion in different slopes and gully under different types of land utilization is measured. The results show that the characteristics of soil grain under different types of land utilization are closely correlated to the extent of soil loss. With the increasing of soil loss, the sorting coefficient for soil particle diameter of A layer decrease in different types of land utilization. The symmetry of diameter groups is low in different types of land utilization. Sediment in granite area of Three-Gorges mainly originates from soil erosion in slope. Sediment yielded from slope chiefly comes from arable land located at slope, and the quantity of sediment yielded from arable land located at the slope above 25°accounts for about 50% of the total sediment yielded from slope.