植被过滤带非点源污染及其对净化效果的影响

Nonpoint Source Pollution of Vegetative Filter Strip and Its Effect upon Purification Efficiency

利用野外小区试验,探讨了植被过滤带非点源污染的产生及其对净化效果的影响。结果表明:总氮、总磷在植被过滤带初始出流中呈现出较高的浓度;在入流单宽流量大于0.004 m3/(s.m)的大流量冲刷下,植被过滤带出流悬浮固体的浓度大多增加;当植被过滤带内土壤初始氮浓度较高时,径流会再次受到氮污染。植被过滤带内坡面和表层土壤的初始情况(污染物量和干湿度)以及入流流量是植被过滤带产生非点源污染的主要因素;非点源污染的产生是植被过滤带净化效果降低的主要原因。

The field plot experiment is used to discuss the emergence of non-point source pollution of vegetation filter strip（VFS） and its effect upon purification efficiency.Results show that initial concentration of total nitrogen and total phosphorus is higher than the average concentration along the VFS;suspended solids concentration of export of VFS increase substantially in the larger unit flux than 0.004 m3/（s·m）;when the initial nitrogen concentration in VFS＇s soil is higher,nitrogen pollution will occur again in surface runoff.The process of non-point source pollution producing is primary reason for effectiveness reduction of VFS.The initial situation including concentration of pollutants and degree of humidity in slope and surface soil,and inflow rate will have a significant impact on non-point source pollution occurred in VFS.The process of non-point source pollution emergence is primary cause for effective reduction of VFS.