外源氮素对人工湿地N2O排放通量影响的研究

氮素通过干湿沉降、地表径流、农业灌溉等途径进入湿地中,导致湿地N2O的产生和排放发生变化,而N2O是一种温室气体,具有较高的温室效应潜力,会对环境造成严重影响。本研究模拟白洋淀芦苇湿地,构建人工模拟湿地系统进行外加氮素试验,用静态暗箱-气相色谱法进行N2O的通量观测,研究外源氮素输入对湿地N2O排放通量的影响。结果表明,外源氮素形态的不同不仅影响湿地系统中环境因子的改变,还会影响氮素进入湿地系统后的迁移转化。硝态氮是湿地N2O产生和排放的主要影响因子,芦苇湿地系统中氮素的反硝化作用强于无植被湿地系统,N2O的排放主要发生在反硝化过程中。

Research of exogenous nitrogen input on N2O fluxes in constructed wetland

Exogenous nitrogen could be an input into wetlands throught dry-wet deposit ion, surface runoff and irrigat ion, which would affect the change of N2O produce and emission. N2O is one of the greenhouse gases and has high potent ial greenhouse effect which will bring serious effects on the environment . The effects of exogenous nitrogen input on the N2O fluxes in simulation of a constructed wetland have been studied by applying closed opaque chamber and gas chromatography system in this paper. The results showed that the difference in exogenous nitrogen could not only change the environmental factors but also affect the transformation of nitrogen in wetlands. The analyses also show that NO-3 is a main factor for N2O fluxes. The denitrification is prominent in constructed wetlands with bulrush than those with no plant, and it is an important process for the N2O fluxes in wetlands.