植被缓冲带对农业面源污染物的削减效益研究进展

农业面源污染对环境安全的影响已超过城市生活污染和工业污染,成为水污染的最主要来源。植被缓冲带能够有效拦截农业面源污染物,减少污染物向水体的排放。通过搜集国内外学者对缓冲带的研究结果,对缓冲带削减农业面源污染物能力、缓冲带最佳宽度等方面的研究进行总结分析。结果表明:(1)5 m草本缓冲带对污染物的拦截作用最好,当缓冲带宽度超过5 m时,推荐使用灌草缓冲带,而乔灌草缓冲带需要超过30 m才能发挥作用;(2)当缓冲带宽度相同时,悬浮物和磷素相较于氮素更容易被拦截,悬浮物及磷素去除的缓冲带最佳宽度推荐为15 m(削减率70%以上),但去除氮素的最佳宽度推荐为30 m(削减率为80%);(3)植被缓冲带拦截污染物受缓冲带宽度、坡度及植被类型等因素影响,但缓冲带宽度与削减率之间的关系并不总是呈正比例,当缓冲带宽度增加到一定大小时,缓冲带对污染物的削减率将不再有明显改变;缓冲带坡度与削减率之间也并不总呈反比例,轻微的坡度能够促进径流下渗作用从而增加缓冲带的削减率。

Research Progress on the Effects of Vegetation Buffer Zone on Reducing Agricultural Non-point Pollution

The impact of agricultural non-point source pollution on environmental safety has surpassed urban living pollution and industrial pollution, and has become the main source of water pollution. The vegetation buffer zone can effectively intercept agricultural non-point source pollutants and reduce the discharge of pollutants into water bodies. Through the collection of domestic and foreign scholars'' research results on buffer zones, this paper summarized the research on the ability of buffer zone to reduce agricultural non-point source pollution and the optimal width of buffer zone. The results showed that:(1) The 5 m herb buffer zone had the best interception effect on pollutants. When the buffer zone width exceeded 5 m, it was recommended to use the grass-blown buffer zone, which needed more than 30 m to function. (2) When the buffer zones width was the same, the suspended matter and phosphorus were more easily to be intercepted than nitrogen. The optimal width of the buffer zone for the suspension and phosphorus removal was recommended to be 15 m (reduction rate of 70% or more). But for nitrogen removal, the recommended width was 30 m (the reduction rate was 80%). (3) The interception of pollutants by vegetation buffer zone was affected by many factors such as buffer width, slopes and vegetation types. But the relationships between buffer zone width and reduction rates was not always proportional. When buffer zone width increased to a certain size, the reduction rates of pollutants would not change significantly. The slopes of the buffer zone were not always inversely proportional to the reduction rates. A slight slope could promote runoff infiltration and thus increase the reduction rates of the buffer zone.