简介：Thedepletionrateofphosphateinthesoil-rootinterfacezoneincreasedalongwithgrowthandphosphateuptskeofwheatormaize,whichindicatedthatthephosphatedistributioninsoilneartherootsurfaceagreedwellwiththephosphatemovementinrhizosphereandphosphateuptakebyplant,Therelativeaccumulationzoneofphosphatewithin0.5mmapartfromtherootsurfacedevelopedatthe15thdayorsoaftercultivatingwheatormaizesincetherootphosphatesecretionincreasedgraduallyinthisstage.Thephosphatedistributioninthesoil-rootinterfacezoneagainstthegrowingtime(t)andthedistancefromtherootplane(x)couldbedescribedbythenon-linearregressionequationwiththethirdpowersofxandt.

简介：Inordertoinvestigatetheeffectsofmicroorganismsandtheirureaseactivitiesinmacrophyticrootzonesonpollutantremoval,foursmall-scaleplots(SSPs)ofvertical/reverse-verticalflowwetlandsweresetuptodetermine:a)therelationshipbetweentheabundanceofmicroorganismsintherootzonesandwaterpurificationefficiency;andb)therelationshipbetweenureaseactivitiesintherootzonesandpollutantremovalinaconstructedwetlandsystem.Totalnumbersofthemicrobialpopulation(bacteria,fungi,andactinomyces)alongwithureaseactivitiesinthemacrophyticrootzonesweredetermined.Inaddition,therelationshipsbetweenmicrobialpopulationsandureaseactivitiesaswellasthewastewaterpurificationefficienciesoftotalphosphorus(TP),totalKjeldahlnitrogen(TKN),biochemicaloxygendemandin5days(BOD5),andchemicaloxygendemand(COD)werealsoanalyzed.Theresultsshowedthattherewasahighlysignificantpositivecorrelation(r=0.9772,P＜0.01)betweenthenumberofbacteriaintherootzonesandBOD5removalefficiencyandasignificantnegativecorrelation(r=-0.9092,P＜0.05)betweenthenumberoffungiandtheremovalefficiencyofTKN.Meanwhile,therewasasignificantpositivecorrelation(r--0.8830,P＜0.05)betweenureaseactivitiesintherootzonesandtheremovalefficiencyofTKN.Thus,duringwastewatertreatmentinaconstructedwetlandsystem,microorganismandureaseactivitiesintherootzoneswereveryimportantfactors.

简介：Availablewaterandfertilizerhavebeenthemainlimitingfactorsforyieldsofspringwheat,whichoccupiesalargeareaoftheblacksoilzoneinnortheastChina;thus,theneedtosetupappropriatemodelsforscenarioanalysisofcroppingsystemmodelshasbeenincreasing.ThecapabilityofCropSyst,acroppingsystemsimulationmodel,tosimulatespringwheatgrowthofawidelygrownspringcultivar,'Longmai19',intheblacksoilzoneinnortheastChinaunderdifferentwaterandnitrogenregimeswasevaluated.Fielddatacollectedfromarotationexperimentofthreegrowingseasons(1992-1994)wereusedtocalibrateandvalidatethemodel.Themodelwasrunfor3yearsbyprovidinginitialconditionsatthebeginningoftherotationwithoutreinitializingthemodelinlateryearsintherotationsequence.CropinputparametersweresetbasedonmeasureddataortakenfromCropSystmanual.Afewcultivar-specificparameterswereadjustedwithinareasonablerangeoffluctuation.TheresultsdemonstratedtherobustnessofCropSystforsimulatingevapotranspiration,abovegroundbiomass,andgrainyieldof'Longmai19'springwheatwiththerootmeansquareerrorsbeing7%,13%and13%oftheobservedmeansforevapotranspiration(ET),grainyieldandabovegroundbiomass,respectively.AlthoughCropSystwasabletosimulatespringproductionreasonablywell,furtherevaluationandimprovementofthemodelwithamoredetailedfielddatabasewasdesirableforagriculturalsystemsinnortheastChina.

简介：植物侵略可以改变碳(C)和氮(N)周期，而是方向，如此的改变的大小很少被确定了，这长被认出了。在这研究，我们确定了效果由有害异国情调的植物的侵略引起了，Kalanchoedaigremontiana(Crassulaceae)，在在在委内瑞拉的一个半干旱的地区的土壤的C和N矿化作用和酶、微生物引起的活动上。我们比较了与这些进程(脱氢酶，-glucosidase,glucosaminidase，和urease的C和N矿化作用时间和累积的值，荧光黄diacetatehydrolytic活动，和活动)在之间联系的土壤参数入侵并且邻近的非入侵的地点。另外，在这些参数之中的关联和物理化学药品的性质也是的土壤检验了决定积极反馈是否在滋养的可获得性和K之间存在。daigremontiana侵略。总的来说，我们的结果证明到NH4+的有机化合物的那个C矿化作用和转变在K开拓殖民地于的地点被赞成。daigremontiana。与这种，我们发现了NH4+-N和C和最低矿化作用时间的最高累积的数量。这些结果能被urease和glucosaminidase的更高的活动在K的影响下面在土壤解释。daigremontiana。另外，有机物和潮湿的更高的数量在入侵的土壤力量帮助C和N矿化作用满足。在结论，由K的新热带区的半干旱的地区的侵略。daigremontiana可以影响这种盖住的土壤的化学、生物的性质，增加滋养的bioavailability，及时，它能便于侵略过程。

简介：土壤温度是土壤上的一个主要有效因素并且种生物性质。灌溉能影响土壤温度并且从而在植物生长上导致温度效果，它可以由于更高的产量和植物营养导致经济增加。一个地实验被执行包括完整的灌溉(FI)调查三灌溉策略的效果，弄干的部分根地区(PRD)和土壤温度上的赤字灌溉(DI)和谷物上的作为结果的结果让步并且玉米(泽·梅L.)的N举起。土壤温度被时间领域反射计(TDR)测量传感器在2010成长季节期间。灌溉处理在种以后从55～107d被使用。PRD处理引起了土壤温度在为一个更长的时期的一个有利领域(为超过60%测量日期)作为到更深的土壤层的水运动的作为结果的结果与另外的处理相比；PRD处理也在更深的土壤深度把土壤温度归结为在为玉米根生长的最大的有利土壤温度下面，它由于水可获得性和有利土壤温度导致了更深的根穿入。比作FI治疗，PRD治疗增加了根水举起50%并且当这没在植物生长上由于DI的否定温度效果部分在DI治疗被观察时，没在全部的N举起引起重要减小，它因而影响了水和滋养的举起。在PRD处理的一个更长的植被时期在FI处理由于更高的叶N集中被观察，在玉米谷物产量的重要减小都没发生在PRD处理，与那些相比。在结果上基于，让15.2%流水在完整的成长季节期间节省，PRD灌溉将断然影响是的土壤温度和水和滋养的举起一作为结果，它将从而在玉米谷物产量阻止重要减小。