利用河岸缓冲带去除径流水中氮的研究

The Study on Removing Nitrogen in Runoff Water by Riparian Buffer Strips

2015年5月7日、7月13日和9月10日,以太湖流域构建的平缓坡度人工林河岸缓冲带为研究对象,比较了不同宽度(5 m、15 m、30 m和40 m)、不同植物类型(杨树林、中山杉林和杨树中山杉混交林)、不同植物密度(400株/hm2、1 000株/hm2和1 600株/hm2)的河岸缓冲带对不同深度径流水中总氮(TN)、铵态氮(NH4+—N)和硝态氮(NO3-—N)的去除率。研究结果表明,随着缓冲带宽度的增加,对径流水中各形态氮的去除率增大。15 m宽的河岸缓冲带已经能很好地去除各种形态的氮。在同一宽度和植物类型条件下,缓冲带对40 cm深度的径流水中的铵态氮和硝态氮的去除率较大,对20 cm深度的径流水中的总氮的去除率较大。种植混交林的缓冲带对总氮的去除率较高,种植杨树林的缓冲带对铵态氮的去除率较高。不同植物密度的缓冲带对各形态氮的去除率差异不显著。

In the study, a slight slope of the artificial riparian buffer zone of Taihu Lake was constructed as the research object. The effects of different riparian vegetation buffer strips with various width（5 m, 15 m, 30 m,40 m）, vegetation types（Ascendens mucronatum, Poplar Nanlin 95, mixed forests of Ascendens mucronatum and Poplar Nanlin 95） and density（400, 1 000, 1 600 stem per hectare） on the total nitrogen, ammonia nitrogen and nitrate nitrogen removal rates in different depth of runoff water were studied. The main results showed that with the increasing of the riparian zone width, the removal rates of nitrogen runoff water increased, but the buffer strips of 15 m width can effectively remove nitrogen. Under the same width and vegetation type, the removal rates of runoff water at 40 cm below ground depth ammonium nitrogen and nitrate nitrogen was bigger, 20 cm depth runoff water total nitrogen removal rate was bigger. Mixed forests of total nitrogen removal rate was higher, Poplar Nanlin 95 of ammonium nitrogen removal rate was higher. There was not significant difference in terms of nitrogen removal rate between different plant densities of buffer strips.