【摘要】 大气核爆产物137Cs能够强烈地被土壤颗粒所吸附,是一种示踪土壤运移的良好示踪剂。通过对紫色丘陵区响水滩小流域不同地貌部位和不同土地利用类型下土壤剖面中137Cs含量的测定与分析,计算了流域各地貌部位、土地利用类型的侵蚀强度。研究得出该流域137Cs含量的背景值是1870 Bq/m2;流域内坡耕地、林地的年均侵蚀强度分别是4468 t/(km2.a)和1759 t/(km2.a);丘顶、丘坡和鞍部的年平均侵蚀强度分别是2125,4676 t/(km2.a)和3625 t/(km2.a),槽土和水田则是沉积区。分析结果表明地貌部位和土地利用类型对土壤侵蚀影响巨大,坡耕地是该小流域泥沙的主要来源。更多还原

【Abstract】 Cesium-137,a fallout product of atmospheric nuclear tests,is strongly adsorbed to soil particles and can be used to trace soil movement.In this paper,the inventories of fallout137Cs in soil profiles were used to estimate soil losses from various landform positions and different land use types in Xiangshuitan catchment in Purple Hilly Area.The reference Cesium-137 inventory of study area is 1 870 Bq/m2.Mean annual net soil losses were 4 468 t/(km2·a) of slope cultivated land and 1 759 t/(km2·a) of forest land.In different landform positions,the mean annual net soil losses in hilltop,hillside and nek were 2 125 t/(km2·a),4 676 t/(km2·a) and 3 625 t/(km2·a),respectively.And the paddy field and the cultivated land located at the foot of hills were deposition area.The results suggested that the landform positions and land use types significantly influenced the rates of soil erosion,and the slope farming land was the chief source of sediment in this catchment in Purple Hilly Area.更多还原