Abstract:

Spatial difference of soil erosion in Muyang river watershed was analyzed by SWAT hydrological model. The research was carried out based on the meteorological data from 1993 to 2009 and land use data in 2009 in Songhuaba water source area and Kunming city, and the second national general soil survey data as well as the observed data of runoff and sediment discharge in the small watershed. Results showed that the interannual peak and valley values of precipitation and sediment discharge were in good coherence. While within the year, the sediment discharge occurred mainly from June to September. The average soil erosion modulus varied from 21.4 t/(km²·a) to 4 586.5 t/(km²·a), indicating that the soil erosion is mainly between middle to moderate levels. The spatial variation of soil erosion is closely related with land use type and topography and slope angle. Interannual variations of soil erosion modulus and precipitation were also in consistency. The research provides basis for estimating the spatial distribution of soil erosion and making targeted conservation measures.

Key words: soil erosion , small watershed , Songhuaba water source area