滨河湿地不同植被对农业非点源氮污染的控制效果  

Effect of different vegetation types on agricultural non-point nitrogen pollution in riparian wetlands

作　　者：徐华山[1,2,3] 赵同谦[3] 贺玉晓[3] 徐宗学[1,2] 马朝红 

机构地区：[1]北京师范大学水科学研究院 [2]水沙科学教育部重点实验室,北京100875 [3]河南理工大学资源环境学院,河南焦作454003 [4]黄河国家湿地保护区孟津管理局,河南471100

出　　处：《生态学报》2010年第21期5759-5768,共10页Acta Ecologica Sinica

基　　金：教育部新世纪优秀人才支持计划项目(NCET-09-0120);中国科学院城市与区域生态国家重点实验室开放基金(SKLURE2010-2-4);国家自然科学基金项目(30570276);河南省教育厅自然科学研究计划项目资助(2010B610006)

摘　　要：滨河湿地作为连接河流水体和陆地的一个功能过渡界面区,是河流生态系统与陆地生态系统进行物质、能量、信息交换的一个重要过渡带,也是保护河流水体的最后一道屏障,对水质净化和农业非点源污染控制起着非常重要的作用。以黄河湿地国家自然保护区孟津扣马段为研究对象,采取野外定位观测试验和稳定同位素示踪(人工富集15N源的同位素稀释法)相结合的方法,研究了滨河湿地土壤对农业非点源氮的持留作用、渗漏到地下水中的农业非点源氮和湿地不同植被对滞留在土壤中的农业非点源氮的吸收作用。结果显示:通过地表径流进入滨河湿地的农业非点源氮在3个实验样方的垂向和侧向都发生了渗漏。滨河湿地土壤对农业非点源氮的滞留作用主要发生在0—10cm,相当于一个过滤器的功能。3种受试植被土壤表层的滞留量为芦苇(0.045mg/g)>藨草(0.036mg/g)>水烛(0.032mg/g),分别占到土壤滞留氮的59.2%、56.3%和56.1%。滞留在土壤中的农业非点源氮污染存在一个相对较长的效应。滨河湿地特殊的氧化还原条件导致强烈的土壤微生物反硝化作用以及滨河湿地植被对氮素的吸收作用,使得0-10cm土层土壤外源氮变化速度最快,1个月后,滞留芦苇、水烛、藨草样方中15N下降了77.8%、68.8%和8.3%;3个月后,芦苇、藨草、水烛样方中的15N下降了93.3%、72.2%和37.5%。滨河湿地复杂的水文过程,使得滞留在土壤表层的农业非点源氮迁移转化更为复杂多变。监测数据显示,在实验设计的浓度和强度范围内农业非点源氮没有对地下水造成影响。不同植被和同一植物的不同生长时期对滞留在土壤中氮的吸收能力差别较大,吸收量依次为芦苇嫩芽(9.731mg/g)>老芦苇(4.939mg/g)>藨草(0.620mg/g)>水烛(0.186mg/g)。通过对生物量计算得出滨河湿地芦苇、水烛和藨草对农业非点源氮的吸收能力分别为氮吸收量96As a functional transition interface connecting rivers and lands,riparian wetlands are one of the major transition zones for matter,energy,and information transfer between aquatic and terrestrial ecosystems. It is also the last barrier to protect the water quality in rivers,and play an important role in water purification and non-point pollution control. With the combination of field experiments and isotope trace technique （ the 15N-enriched method） in Kouma section of the Yellow River,retention of agricultural non-point nitrogen pollution by the soil in riparian wetland,the proportion of agricultural non-point nitrogen which leaks into the groundwater,and the absorption of agricultural non-point sources nitrogen pollution by different vegetation types in riparian wetlands were investigated. The results showed that the agricultural non-point sources nitrogen flowing into riparian wetlands through surface runoff infiltrated into the subsurface and dispersed both vertically and horizontally in three experiment plots. Retention of agricultural non-point nitrogen pollution by the soil in riparian wetlands mainly occurred in the soil layer at top 0 -10 cm,and the amount of nitrogen retained by surface soil associated with three types of vegetation were 0. 045 mg/g for Phragmites communis Trin plots,0. 036 mg/g for Scirpus triqueter plots,and 0. 032mg/g for Typha angustifolia plots,which accounted for 59. 2% ,56. 3% ,and 56. 1% of the total nitrogen interception,respectively. The top soil layer （ 0 -10 cm） of riparian wetland acts as a filter. A long period pollution effect exists in agricultural non-point nitrogen that remained in the soil. Strong denitrification function of soil microorganisms in the extraordinary oxidation-reduction condition of riparian wetland and uptake by plant in riparian wetland make agricultural non-point nitrogen in the 0 -10 cm soil layer change more quickly than those in other layers. After K15 NO3 was added to the surface soil,nitrogen content decreased by 77. 8% for Phragmites co

关 键 词：滨河湿地 植被样方 农业 非点源污染 氮污染 

分 类 号：X52[环境科学与工程—环境工程]