不同植物篱坡面的土壤侵蚀过程CA模拟

在一般元胞自动机(CA)模拟方法的基础上,将土壤侵蚀的水力学原理引进CA模型,改进其系统演化的规则,从而建立了可以模拟不同植物篱影响下的坡面土壤侵蚀过程模型,植物篱对于土壤侵蚀的影响使用产流和产沙因子来描述。结合在4个栽有不同植物篱的试验小区和一个对照小区进行的人工降雨侵蚀试验,利用该模型分别对5个小区的水土流失情况进行了模拟,并对模拟结果以及引起模拟误差的原因进行了分析。通过试验观测结果与模拟数据的对比分析发现,该模型可以很好地模拟不同植物篱影响下的坡面累积产流和产沙强度。观测和模拟的结果分别表明植物篱可以显著地减少坡面土壤的流失量,并且不同的植物篱的作用不同,其中,香根草植物篱具有最好的水土保持作用。

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.