湖滨湿地土壤渗滤液NP分布规律及影响因素的探讨

采用PVC管为渗滤管柱，对五里湖湖滨带芦苇湿地土壤渗滤液进行分层取样，研究了湖滨带湿地土壤渗滤液N、P的空间分布规律及其与Eh、TOC、根系生物量、微生物的关系。结果表明，从整体上看，湖滨芦苇湿地土壤渗滤液中TN、N03^--N、TP含量随深度的增加而降低，到60cm深度附近降到最低，然后又略有回升，而NH4^＋-N含量随深度增加而升高。在垂直分布上，表层呈好氧环境，氧化还原电位高，TN含量高，硝化细菌活跃，产生大量的硝态氮；随着深度的增加，环境氧分压愈低，反硝化愈强，NO3^--N和TN下降，而硝化菌的硝化作用受到抑制及氨化作用，NH4^＋-N逐渐得到积累。表明湖滨带湿地土壤渗滤液N、P含量与TOC、Eh、根系生物量及硝化菌数量密切相关，在湖滨芦苇湿地深60cm以上具有较佳的综合生态效应，这对指导湖滨带的生态恢复与重建的实践，充分发挥湖滨带的生态功能具有重要的现实意义。

Influencing Factors and the Laws of Spatial Distribution of Nitrogen and Phosphorus in Soil Solution in Aquatic-terrestrial Ecotone

The laws of spatial distribution of N and P in soil solution in aquatic-terrestrial ecotone(ATE)of Lake Wulihu,a reed wetland,were studied,as well as the relations of N,P with Eh,TOC,root system biomass and microorganism.As a whole,the content of TN,NO-N,TP of soil solution in ATE decreased gradually with the soil depth increasing,and reached the minimum in the depth of around 60 cm.But the content of NH-N increased with the increased depth.The content of NO-N in surface of soil solution were obvious higher than that in undersurface since the Eh in surface was higher and nitrifying bacteria was more active.The content of NH-N in undersurface of soil solution was higher than that in surface since the nitrification was limited for low Eh and ammoniation was strengthened.In addition,the vertical variation of N and P in soil solution in ATE was significant.The variation coefficient of NO-N along the depth was reached 124.07%,the biggest among TN,TP,NO-N,NH-N and organic nitrogen,while the variation coefficient of organic nitrogen was 39.22%,the smallest,which contributed to that NO-N was easy to move,while the organic nitrogen was strongly adsorbed by the soil colloid.The variation of N and P between adjacent layers in soil solution was obvious different.The organic nitrogen varied most from 60 cm to 80 cm,whereas others varied most from 20 cm to 40 cm.The content of nitrogen and phosphorus strongly correlated with TOC,Eh,root system biomass and the number of nitrifying bacteria.It can be concluded that there exists the optimum ecological efficiency in the depth of above 60 cm in reed wetland,which will be very significant for ecological restoration and reestablishment.