用^(137)Cs研究段家河流域土壤侵蚀的基本规律

USING CAESIUM-137 TO INVESTIGATE SOIL EROSION WITHIN DUANJIA RIVER CATCHMENT

本文简述了选择^(137)Cs为示踪剂的主要依据和^(137)Cs含量与土壤侵蚀量的关系。描述了样品采集和测量方法。推算了段家河流域四个剖面的土壤侵蚀量,提示了该地区土壤侵蚀的基本规律。

Since 1954, to use the radioactive isotop Caesium-137 as tracer to investigate a rule of soil erosion has been fast developed. This paper describes main sources about using Caesium-137 as tracer and connection between the contents of Caesium-137 and soil erosion, taking and measuring of the samples. We estimate the soil erosion of four profiles within Duanjia river catchment. The results verify:1) . The background of Caesium-137 within Duanjia river catchment is (2169. 6?38.7)Bq/m2.2) . In un-cultivated land, Caesium-137 collects in 5cm soil under land surface. It quitedecreases downwards. But the content of Caesium-137 is nearly equal in the cultivated land.3) . The law of the soil erosion is as follows: Generally, the erosion in the forest zone is negligible, The soil erosion in horizontal cultivated land where is protected well is less than 1000t/km2 . a, In the region, where was naked before 1986 but is badly covered with natual trees, the equilibration of the soil erosion is 1576.8 t/km2 . a, In area, where was bush but since 1986 is new cultivated land, the equilibration of erosion is 1905 t/km2 . a, The soil erosion in slope cultivated land is awful, it is deeply more than 2000t/ m2 . a,There is no difference on the soil erosion in cathment between middle-lower rearches of Duanjia river.4) . The soil's piling is evident. Somewhere, there are pile and erosion. But it is neces-sary to investigate their quantities, respectively.