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1、siltetc.Besides,thejujubetresshasthebiologicalfeaturesoftoleratingdrought,cold,infertility,saltandalkali.AccordingtothelandformsofNeihuangcounty,farmerssinthisareahavebeenchoosingtogrowerjujubetrees.Practicehasprovedthatjujubetreesgrowinginthisareabasicallyrealizestheoptimalcombin
2、ationofeconomyandecology.Therefore,jujubetreeshavebeenhighlypromotedinNeihuangcountythedryweatherinspring,nearly80%ofthegroundwaterisusedinagriculture.However,theuseofwaterresourcesislow-efficientduetofloodingirrigation.Thishasgivenrisetosomeecologicalproblems,secondarysalinizatio
3、nofsoilforexample.NeihuangcountyistheancientcourseoftheYellowRiverandaboundsingroundwaterwhichlivesuptothestandardofirrigation.ThesoilinthisregionhasrelativelyloworganiccontentandmoderatepHvaluewithrichtotalphosphorusandinsufficienttotalpotassiumandnitrogen.Traceelements(e.g.Zn,Mn
4、,Cu,Fe,B)areinadequateindifferentlevel.Therefore,itisnecessarytosupplementbio-fertilizer,nitrogenousandpotashfertilizerandtocontrolphosphatefertilizerwhileaproperamountofsuchtraceelementsasS,Fe,Mn,ZnandBshouldbeadded.Ingeneral,thereddateinthisareaisofhighyieldandofgoodquality,abou
5、ndingwithaminoacids,carbohydratesandvitamins.Thefreshdatestastesourandsweetwhilethedriedonestendtobefragrantandsweet.KEYWORDS:jujubetreesgrowth,climate,soil,hydrology,yieldandqualityofreddatesIV目录摘要...................................................................................
6、...................................................................................IABSTRACT.............................................................................................................................................................III1绪论..........................
7、..........................................................................................................................................11.1选题背景和意义....................................................................................................................................
8、11.1.1选题背景.......................
