PRELIMINARY ESTIMATE OF SOIL EROSION MODULUS IN THE DAGUHE RIVER BASIN USING ¹³⁷CS TRACING METHOD

The ¹³⁷Cs tracer method was used for estimate of soil erosion in the Daguhe River Basin. Also discussed are the process and features of erosion, the relationships between soil erosion and the erosional depth and soil granularity. The soil erosion modulus of the Xiaoguhe River and the upper Daguhe River is 468 t/(km²·a) and 308 t/(km²·a) respectively, both belonging to moderate water erosion. In soil profiles, ¹³⁷Cs is mainly concentrated below about 30 cm in depth. No peak has been found in top soils. There is an obvious positive correlation between ¹³⁷Cs concentrations and soil grain sizes, especially for the soils bigger than 4 φ (<0.063 mm). It is inferred that ¹³⁷Cs was mainly adsorbed on the surface of silly sand and clay minerals, rather than coarse particles.