1、中國農(nóng)業(yè)大學博士學位論文幼齡楊樹和小麥玉米復合系統(tǒng)土壤水分和養(yǎng)分時空變化及作物表現(xiàn)姓名：戴曉琴申請學位級別：博士專業(yè)：作物栽培學與耕作學指導教師：謝光輝王璞20060601中國農(nóng)業(yè)大學博士學位論文AbstractAbstractThreeseriousandlinkedproblems，suchaspopulationgrowth，resourcedepletionandenvironmentaldegradatinn，haveinfl

2、uencedtheeconomicincreaseandthelifequalityofpeopleintheworldThesearchforhighlyproductive，yetsustainableandenvironmentallyresponsibleagriculturalsystemshasledtoarenewedinterestinagroforestrypracticesintemperateregionsofth

3、eworldTheagroforestrysystemscanutilizelight，heat，waternutrientandlandhighlyeffectivelytherebyimprovethesystemproductivitybutalsoprotecttheenvironmentandpromotetheecologicaldevelopmentTheperennialwoodyspeciesintroducedint

4、othesoleagriculturalsystemwillalterthetemporalandspatialchangesin‘soilwaterandnutrientsoftheagriculturalsystem，therebyinfluencethechangesincropwaterandnutrientuseandsystemproductivityTheampleprovideofsoilwaterandnutrient

5、isthemainfactorsofcrophigheryieldTherefore，itiscmcialtoelucidatethetemporalandspatialchangesinsoilwaterandnutrientsandtheinfluenceofthepoplaroncropwaterandnutrientuseformanagingagroforestrysystemsandevaluatingitssustaina

6、bilityThestudyinvestigatedanagroforestrysystemofyoungpoplar(Populus)treesintercroppedwithwheat(Triticumaestivum)andmaize(Zeamays)incomparisontosolewheatandmaizecroppingsystemin20032005，inwhichthetemporalandspatialchanges

7、insoilwaterandnutrients，theeffectofthepoplartreesoncropgrowthandthechangesinsoilfertilityweremeasuredandanalyzedTheresultswereasfollowing：1Wefoundnosignificantdifferencesinbiomassandgrainyieldofwheatbetweentheintercroppi

8、ng12yearoldpoplarandthesolewheatsystemswithineachfertilizationtreatment，whereasbiomassandyieldofmaizeintheagroforestrysystemweresignificantlylessthanthatinthesolemaizeReductioninmaizebiomassandgrainyieldwas372％and307％，an

9、d313％and337％forthefertilizedandnon—fertilizedtreatments，respectivelyButtheresultsshowedgrainyieldsofwheatandmaizeatcropmaturityweresignificantlylowerintercroppedwith3～4yearoldpoplarwhichspatiallyinthenorthofthealleywereh

10、igherthaninthesouthThereductioninwheatandmaizewas369％425％and808％～87|4％，respectivelyInviewofyieldcomponents，themostfactorinfluencedwheatyieldwasearnumberHoweverthemainfactorsinfluencedmaizeyieldvariedwiththepoplargrowthTh

11、eresultsshowedthatthemaininfluencingfactorwasgrainnumberformaizeyieldwhenintercroppedwiththeyoungerpoplarandthenitchangedtoearnumberwhenintercroppedwiththeolderpoplar2TherewerenosignificantdifferencesinN，PandKconcentrati

12、onbetweentheagroforestrysystemandthesolecroppingsystemeitherinthefertilizedorinthenon—fertilizedtreatmentforwheatandmaizeNosignificantdifferencesinN，PandKuptakewerefoundinwheatbetweentheagroforestryandthesolecroppingsyst

13、emsHoweve5maizeintercroppedwithpoplarexhibitedsignificantlylowerN，PandKuptakethanthesolemaizeforthefertilizedtreatmentduetoalowerbiomassyield，whichwereapparentlyinfluencedbylightinmaizeseasonThoseresultsindicatethatthe12