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1、第22卷第2期水土保持學(xué)報Vol.22No.22008年4月JournalofSoilandWaterConservationApr.,2008模擬降雨條件下農(nóng)田地表徑流與壤中流氮素流失比較李恒鵬,金洋,李燕(中國科學(xué)院南京地理與湖泊研究所,南京210008)摘要:選擇太湖流域平原河網(wǎng)地區(qū)為試驗地點,采用3次重復(fù)人工暴雨試驗方法,研究暴雨徑流過程中地表徑流與壤中流氮素流失特征。結(jié)果表明:地表徑流與壤中流氮素流失特征具有較大差異,地表徑流水相TN平均濃度為12.41mg/L,壤中流水相TN平均濃度低
2、于地表徑流約50.65%。地表徑流氮素流失以PN為主,DN和PN的流失量比為1∶2.65,壤中流氮素流失以DN為主,DN和PN流失量比為2∶1。整個暴雨徑流過程中氮素流失以地表徑流為主,占總流失量的81.66%,壤中流氮素流失量相對較少,僅占氮素總流失量的18.34%。地表徑流與壤中流氮素流失量比較分析結(jié)果證實,土壤的水分下滲濾過機制對氮素具有較強的削減作用,對PN的削減作用尤為明顯,可達70%以上。在流域產(chǎn)匯流過程中,充分發(fā)揮洼地和高透水地段對地表徑流的蓄滲功能,對面源營養(yǎng)鹽污染控制具有重要的作用
3、。關(guān)鍵詞:人工降雨;氮素流失;太湖流域;地表徑流;壤中流中圖分類號:S157.1文獻標識碼:A文章編號: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
