Soil erosion modelling for hillslopes with different hedgerows using cellular automata approach

Four hedgerows consisting of different plants were planned on four experimental plots with a size of 10m×2m each on steep slope land(25°) for three years.Under the same land and intercropping management strategy,another plot without any hedgerows was taken as a check plot to test the contribution of hedgerows to soil and water conservation.Artificial rainfall experiments were carried out on these plots.Measured runoff and sediment yields indicated that all kinds of hedgerows could significantly reduce soil loss.It was also observed in our experiments that hedgerows had different behaviors in soil erosion processes.The plant Vetiver had the most efficient contribution to soil and water conservation.A cellular automata(CA) model based on local interaction and hydraulic principles was developed to simulate the soil erosion processes for the five experimental plots in which flow and sediment impact factors obtained from experimental data were employed to evaluate effects of different hedgerows on runoff and sediment yields.In CA model,an actual experimental plot was subdivided into a series of regular square cells in which soil and cover properties were treated as homogenous.In every time step of the model,the flow and sediment were transported from a spatial cell to its neighbor cell with the lowest potential head.The simulation accuracy and computation complexity of this model are determined by the size of the cell,the time step of iteration and choices of hydraulic parameters.The comparison of simulated and measured data suggested that CA is an applicable approach for soil erosion simulation under different hedgerows conditions.