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1、第22卷第2期水土保持学报Vol.22No.22008年4月JournalofSoilandWaterConservationApr.,2008模拟降雨条件下农田地表径流与壤中流氮素流失比较李恒鹏,金洋,李燕(中国科学院南京地理与湖泊研究所,南京210008)摘要:选择太湖流域平原河网地区为试验地点,采用3次重复人工暴雨试验方法,研究暴雨径流过程中地表径流与壤中流氮素流失特征。结果表明:地表径流与壤中流氮素流失特征具有较大差异,地表径流水相TN平均浓度为12.41mg/L,壤中流水相TN平均浓度低
2、于地表径流约50.65%。地表径流氮素流失以PN为主,DN和PN的流失量比为1∶2.65,壤中流氮素流失以DN为主,DN和PN流失量比为2∶1。整个暴雨径流过程中氮素流失以地表径流为主,占总流失量的81.66%,壤中流氮素流失量相对较少,仅占氮素总流失量的18.34%。地表径流与壤中流氮素流失量比较分析结果证实,土壤的水分下渗滤过机制对氮素具有较强的削减作用,对PN的削减作用尤为明显,可达70%以上。在流域产汇流过程中,充分发挥洼地和高透水地段对地表径流的蓄渗功能,对面源营养盐污染控制具有重要的作用
3、。关键词:人工降雨;氮素流失;太湖流域;地表径流;壤中流中图分类号:S157.1文献标识码:A文章编号:1009-2242(2008)02-0006-04ComparativeStudyofNitrogenLossesbetweenSurfaceFlowandInterflowofFarmlandunderArtificialRainfallConditionsLIHeng-peng,JINYang,LIYan(NanjingInstituteofGeographyandLimnologyResea
4、rch,CAS,Nanjing210008)Abstract:SelectingrivernetworkplaininTaihubasinasexperimentplaces,tripleduplicationexperimentshavebeencarriedoutundertheartificialrainstormconditionstoevaluatethecharacteristicsofnitrogenlossesfromsurfaceflowandinterflow.Theresult
5、sshowthattherearesignificantdifferencesbetweennitrogenlossesinsurfaceflowandthatininterflow.Averageconcentrationoftotalnitrogeninsurfaceflowis12.41mg/L,whichishigherthanthatininterflow.Theaverageconcentrationofnitrogenininterflowonlyaccountsforabout50.
6、65%oftheconcentrationinsurfaceflow.Themainformofnitrogenlossinsurfaceflowisparticulatenitrogen,andtheratioofdissolvednitrogentoparticulatenitrogenis1∶2.65.However,thenitrogenlossformininterflowisdissolvednitrogenmostly,andtheratioofdissolvednitrogentop
7、articulatenitrogencomesto2∶1.Inthewholerainstormprocess,nitrogenlossesbysurfaceflowtakethebigproportion,accountfor81.66%ofthewhole,andonly18.34%ofthewholenitrogenlossesisbyinterflow.Accordingtothecomparativeanalysisresultsofnitrogenlossesbetweensurface
8、flowandinterflow,itisconfirmedthatsoilinfiltrationhasstrongnutrientdecayfunction,whichespeciallyisobviousforparticulatenitrogen,reachingmorethan70%.Duringtherunoffoutputandroutingprocess,lowlandandhigh-pervioussurfacecanbeusedforrunoffs
