不同宽度模拟植被过滤带对农田径流、泥沙以及氮磷的拦截效果

Interception of Runoff,Sediment,Nitrogen and Phosphorus by Vegetative Filter Strips with Different Width in a Simulated Experiment

化肥的大量使用在提高作物产量的同时,也导致了严重的环境污染。该研究通过在土槽上进行浑水冲刷试验,定量研究了模拟植被过滤带对径流、泥沙、总氮、以及总磷的拦截效果。结果表明,在进水流量(0.173 L·s-1)和流速(0.7 m·s-1)一定的条件下,模拟植被过滤带的宽度对污染物的拦截效果影响较大。当宽度分别为1、2、3 m时,模拟植被过滤带对径流的拦截率分别为32%、51%、69%;对泥沙的拦截率分别为78%、88%、92%;对总氮的拦截率分别为65%、75%、84%;对总磷的拦截率分别为80%、93%、95%。同时,3种宽度下的泥沙量、总氮量、总磷量均与径流量呈显著线性正相关关系(泥沙量:r1=0.69,r2=0.84,r3=0.63;总氮量:r1=0.98,r2=0.89,r3=0.95;总磷量:r1=0.62,r2=0.47,r3=0.41),表明径流量在一定程度上决定了流经植被过滤带后出流的泥沙量、总氮量以及总磷量。研究证实,茎秆密集的草本植被过滤带能有效拦截径流、泥沙、总氮以及总磷,对农田水土流失和农业面源污染具有较好的防治效果。

Enormous uses of mineral fertilizers greatly increase crop yields,but may cause water pollutions. Vegetative filter strips（VFS）,which planted along streams or lakes to remove sediments and nutrients carried in runoff,have been regarded as one of the best management practices in reducing non-point source pollution in many countries. Interception effectiveness of pollutants by VFS is largely dependent on the width and type（grasses,shrubs,trees,or their mixtures）of VFS and pollutant forms（particle or soluble）. A simulated experiment was conducted in this study to determine the interception effectiveness of runoff,sediment,nitrogen,and phosphorus by artificial grass-like VFS with different widths（1 m,2 m,and 3 m）. The interception effectiveness of runoff and pollutants were greatly influenced by the width of VFS under the same conditions（water flow rate and speed were 0.173 L·s^-1and 0.7 m·s^-1,respectively）. The VFS with 1 m,2 m,and 3 m width respectively reduced the outflow of runoff by 32%,51%,and 69%,and the outflow of sediment by 78%,88%,and 92%. Correspondingly,the outflow of total nitrogen was decreased by 65%,75%,and 84%,and that of total phosphorus by 80%,93%,and 95%,respectively. The total outflow of sediment,nitrogen,and phosphorus was significantly positively correlated with the outflow of runof（famount of sediment：r1=0.69,r2=0.84,r3=0.63;amount of total nitrogen：r1=0.98,r2=0.89,r3=0.95;amount of total phosphorus：r1=0.62,r2=0.47,r3=0.41,respectively）. The results indicate that grass VFS are very effective in reducing runoff,sediment,nitrogen,and phosphorus and controlling agricultural non-point source pollution.