模拟黑麦草植被缓冲带对径流中氮、磷以及悬浮颗粒物的截留效果研究

Study of the Reduction of Nitrogen,Phosphorus and Suspended Solids in Simulated Ryegrass Vegetation Buffer Zone

农业面源污染已成为湖泊和河流的主要污染源之一,河岸植被缓冲带的存在可以对面源污染物进行有效吸收和截留。为阻控径流中农业面源污染物向水体的迁移,以模拟黑麦而麦草植被缓冲带为研究对象,采用模拟径流和降雨试验方法,通过6组模拟试验,分析其对地表径流及渗流中氨氮(NH4+-N)、总磷(TP)、溶解态磷(DP)及悬浮颗粒物(SS)的截留、阻控效果。结果表明:黑麦草植被缓冲带对地表径流及土壤不同深度渗流中氮、磷及SS等面源污染物均具有一定的截留效果。模拟径流和降雨条件下,随着渗流取样深度的增加,黑麦草对各形态氮磷污染物的截留效率逐渐增大。模拟降雨条件下,黑麦草植被缓冲带对40cm渗流中NH4+-N、TP和DP的截留效率高于模拟径流中污染物的截留效率,其最大值分别为28.0%,12.4%和25.6%。植物根系吸收、土壤的入渗以及土壤吸附等作用是黑麦草植被缓冲带对地表径流和渗流中各形态氮磷及SS的截留、阻控作用机制。

Agricultural non-point source pollution ha s become one of the main pollution sources of lakes and rivers. The existence of riparian vegetation buffer zone can effectively absorb and retain the agricultural non-point source pollutants. In order to prevent the transfer of agricultural non-point source pollutants to water body in runoff, In this study, the simulated ryegrass vegetation buffer zone was taken as the research object. The simulated runoff and rainfall test methods were used to analyze the interception and control effects of the simulated runoff and infiltration on ammonia nitrogen(NH4+-N), total phosphorus(TP),dissolved phosphorus(DP) and suspended particulate matter(SS). The results show that ryegrass buffer zone has a certain effect on the interception of surface runoff and non-point source pollutants such as nitrogen, phosphorus and SS in different depth seepage. Under simulated runoff and rainfall conditions, with the increase of seepage sampling depth, the interception efficiency of ryegrass to various forms of nitrogen and phosphorus pollutants gradually increased. Under the condition of simulated rainfall,the interception efficiency of ryegrass vegetation buffer zone to NH4+-N, TP and DP in 40 cm seepage is higher than that in simulated runoff, with the maximum values of 28.0%, 12.4% and 25.6%, respectively. Plant root absorption, soil infiltration and soil adsorption are the mechanisms of interception and control of N, P and SS in the surface runoff and infiltration by ryegrass vegetation buffer zone.