Evaluating soil erosion rate in the Dianchi lake basin using 137Cs tracer method

137Cs tracer method was used to evaluate the soil erosion rate in the Dianchi Lake Basin. The results indicate that the soil erosion rate of investigated area is about 224-3546 t/km2yr, the changes depend on the sample from different agricultural land. The extensive cultivation and irrigation also increases the erosion rate of dry farmland on sloping fields, the orders of erosion of different land uses differ from the other region, such as Taihu Lake Basin. Particularly, 137Cs inventories of soil profiles in the Dianchi Lake Basin (355-872 Bq/m2) are lower than those in some other areas of China and the world. The reasons may be its specific climate and location in the outer of the nuclear test base. The soil erosion rates evaluated by 137Cs tracer method are coincident with the observation of field and other estimated methods. Therefore, 137Cs tracer method can be used to evaluate mid-term soil erosion rate of the Dianchi Lake Basin. (authors)