In order to evaluate the effect of land use change on soil erosion process,a mathematical model was developed for simulating runoff generation and sediment transport processes on different slope lands.This model was comprised of two modules:the kinematic-wave equation for overland flow and a sediment transport formula.The measured runoff generation and sediment transport data of bare land,grassland,cropland,scrubs land and young forest land were used for model validation and the simulating values were in good agreement with the measurements.Then the characteristics of runoff generation and sediment transport under different land use scenarios were predicted using the model and the results showed that soil erosion could be greatly controlled on 5-year-old forestland or grassland with coverage more than 60% under the normal rainfall in the loess plateau,and light erosion occurres in the middle and lower part of the bare land with the gradient less than 15°.Only the 10-year-old forestland could provide a good erosion control effect while the effects of grassland and bare land are limited under the once in ten-year rainfall. Both grassland and forestland should be cooperated in combating erosion by taking the advantages of the faster effect of grassland for low intensity and short duration rainfall and the more obvious effect of forestland for high intensity and long duration rains.The slope length should be strictly controlled for bare land with different gradients.
