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用13 7Cs示踪法探讨滇池流域的土壤侵蚀表明 ,不同利用方式农田的侵蚀量从 2 2 4t km2 yr(菜地 )～ 345 6t km2 yr(园地 )。与太湖地区相比 ,粗放的耕作方式也改变了当地农田的侵蚀排序。特别是土壤中的13 7Cs含量为 35 5～ 872Bq m2 ,比世界其他许多地区都低 ,却与青藏高原相邻地区的数值相近。原因可能是气候特点及远离核试验中心。经与其他方式所得结果比较可见 ,用13 7Cs示踪法研究滇池流域的中长期土壤侵蚀既简便快速又合理可行。
The soil erosion in Dianchi Lake Basin by using 13 7Cs tracing method shows that the erosion amount of farmland in different utilization ways ranges from 224 t km2 yr (vegetable field) to 345 6 t km2 yr (field). Compared with the Taihu Lake area, extensive farming methods also changed the erosion order of local farmland. In particular, the 13 7Cs content in the soil is 35 5 ~ 872 Bq m 2, which is lower than many other parts of the world but similar to those in the adjacent areas of the Qinghai-Tibet Plateau. The reason may be the climatic characteristics and distance from the nuclear test center. Compared with the results obtained by other methods, we can see that using 13 7Cs tracer method to study the medium and long-term soil erosion in Dianchi Lake basin is both simple, quick and reasonable.