长江上游紫色丘陵区土壤侵蚀与泥沙输移比研究——以涪江流域为例

 通过涪江流域水文站控制区域的地貌与土地利用类型的综合分析,以不同土地利用类型地块作为侵蚀量计算单元,计算每个流域发生侵蚀的地块（即旱坡地、陡坡旱地、有林地、疏林地、草地、灌木地和裸地）侵蚀量,得到全流域年均侵蚀量为2 460万t/a,年均侵蚀模数为813.9 t/（km2.a）,上游山地区侵蚀模数>1 000 t/（km2.a）,紫色丘陵区侵蚀模数50～0800t/（km2.a）;流域平均泥沙输移比为0.83,上游泥沙输移比>0.90,中下游丘陵区泥沙输移比在0.30～0.80之间,而在流域上中游山地丘陵衔接的冲洪积扇区的年均泥沙沉积量约144万t/a;流域泥沙输移比与流域面积不存在固定的线性关系,其根本原因在于流域面积是度量衡单位,而不是影响因素。

Soil erosion amount and sediment delivery ratio in the hilly purple soil region in the upper reaches of Yangtze River: A case study in the Fujiang River Basin

Based on the analysis of the controlled area of hydrological stations,morphologic landscape and land use types in the Fujiang River Basin,the soil erosion amount of non-irrigated slope land,non-irrigated steep slope land,forest land,open forest land,grassland,shrub land and bare land were calculated.The annual erosion amount of the Fujiang River Basin was 2.46×107t/a,and annual erosion modulus was 813.9t/（km2·a）.The annual erosion modulus in mountainous area in the upper reaches was more than 1000t/（km2·a）,and in the hilly purple soil area was 500-800t/（km2·a）.The average sediment delivery ratio of the Fujiang River Basin was 0.83,while in the upper reaches was 0.90 and in the hilly area in the middle and lower reaches ranged from 0.30 to 0.80.However,there was 1.44×106t/a sediment deposited in the alluvial and diluvial fan area.The sediment delivery ratio is not correlative with the river basin area,because which is not a influence factor but a units of measurement.