植草带对红壤坡耕地面源污染物输出的削减效果

为探讨植草带对红壤坡耕地面源污染输出的削减效果,以植草带和裸露红壤坡面作对照,根据野外观测数据拟定降雨强度和N,P等面源污染物浓度,室内模拟产流产沙及N,P输出过程.结果表明,雨强越小,植草带的减流和减沙效果越明显；在同一雨强条件下,植草带的减沙效果比减流效果明显.与裸地比较,植草带对全N的削减率随雨强和全N输入量增大而逐渐减小；在20 mm/h和35 mm/h雨强条件下,植草带对全P的削减率随着全P输入量的增大而增大,在同一全P输入浓度条件下削减率随雨强增大而逐渐减小；在50 mm/h雨强条件下,植草带径流中全N输出量大于裸地对照.

Reduction Effects of Grass Planting Belt on Non-point Source Pollutants from Cropland in Red Soil Sloping Area

Taking a regular bare slope with red soil as control,the reduction effects of grass planting belt onthe non-point source pollutants from red soil sloping cropland were studied by simulating the quantities ofrunoff,sediment,nitrogen,phosphorus and the erosion processes under the different rainfall intensity conditions integrated with different concentrations of nitrogen,phosphorus and other non-point source pollutantspreset by the data observed in the field.Results showed that the reduction effects on runoff and soil weremore obvious when rainfall intensity was low.The soil reduction effect was more remarkable than the runoffreduction effect under the same rainfall intensity condition.Compared with the bare red soil area,the reduction rate of the total nitrogen(TN)by the grass planting belt was decreased with increases in both rainfall intensity and the input of the TN.The reduction rate of the total phosphorus(TP)by the grass planting beltwas increased with the input increment of the TP under 20and 35mm/h rainfall intensities.When the inputconcentration of the TP was stable,the reduction rate of the TP by the grass planting belt was decreasedwith the increment of rainfall intensity.When rainfall intensity reached 50mm/h,the output of the TN inrunoff from the grass planting belt plot was more than that from the bare red soil plot.