简介：Inapreviousgreenhouseexperiment,weshowedthattherewasaninteractionbetweencuandZn,whichaffectedgrowthandmetaluptakebyyoungbarleyplantsgrownonsoiltowhichCd,Cu,Pb,andZnhadbeenadded.Wesuggestedthattheunderlyingmechanismwasthecontroloftheamountofplant-availableZnbycompetitiveadsorptionbetweenCuandZn,Inordertotestthishypothesis,theadsorptionofZnalone,andinthepresenceofaddedCd,CuandPb,hasbeenmeasuredusingthesamesoil.Followingadsorption,theextractabilityoftheZninCaCl2solutionwasmeasured.TheadsorptionisothermsshowedthatoftheaddedmetalsonlyCuhadalargeeffectonZnadsorption.TheeffectofCuwastoreduceZnadsoptionandtoincreasetheamountofCaCl2-extractable(i.e.plant-available)Zn,inagreementwiththeconclusionsfromthegreenhouseexperiment.ThemagnitudeoftheeffectofCuonplant-avalilableZnwassimilarinbothexperiments.

简介：Soilswerecollectedfrom2-year(2-y)and3-year(3-y)oldred-pineseedlingplotsintwotreenurseries,HaywardinthenorthandWilsoninthesouthwesternpartofWisconsinStaterespectively,andequilibratedwith0.01MCa(NO3)2)forsoilsolutionZnandMn(solu-ZnandMn),andwith0.01MCa(NO3)2+0.005MEDTAforsoilabsorbedZnandMn(ad-ZnandMn).BufferingcapacityofsoilZnandMn(b-ZnandMn)wasobtainedfromtheratioofad-ZnandMntothesolu-ZnandMn.Theconcernedtracesinpineseedlingneedles(ndls),stems(sts)androots(rts)weresimultaneouslymeasured.Theresultsobtainedshowthat:About60%ofsolu-andad-Znrangedfrom0.2to0.4andfrom1to2μg/gsoilrespectively.About70%ofb-Znwaswithin3-10.Thehighestcontentofsolu-Zncomparedwiththelowestshowedadiscrepanceofmorethan10-fold.ThetwoformsofsoilZnwerecommonlyhigherinWilsonthaninHaywarkNursery.About80%ofsolu-,ad-andb-Mnwerewithin3-10,5-5.8μg/gsoiland1-2respectively.Influenceoflowbufferingcapacityonsolu-ZnandMnwasabout20timesstrongerthanthatofthehigh.TheE-value,aratioofaccumulatedZnandMninneedlestothoseinthesoilsolution,isprovedtobe:E-Zn>E-Mn;E-sts>E-ndlsorE-rts;andE-2y>E-3y.Curvilinearand/orlinearcorrelationsbetweensoilsolu-,ad-andb-ZnandMnandndls-,sts-,rts-ZnandMnwereatverysignificantorsignificantlevels.Forpredictingndls-ZnandMn,tworealizableandsimplemodelsfromtworegressionequationswereestablishedthroughtheselectionofrelatedparametersanddependentvariables.BinaryregressionanalysisbasicallyeliminatedtheinfluenceofsoilpHonthepredictionofZnandMninneedles.SoilpHwasthusthoughttobeexcludedfromthemodel.

简介：水稻是我国重要的粮食作物，早日实现水稻种植机械化不但是国家的要求，也是千千万万农民梦寐以求的愿望。在当前高性能插秧机日臻成熟前提下，要搞好水稻育插秧机械化的关键是标准化育秧。育好秧苗的基础是催芽，其主要技术要求是“快、齐、匀、壮”。目前，不少地方采用的催芽方式大都还停留在人工操作加经验上，一旦遇到多雨低温等不利气候影响，即会出现缺苗烂秧。分析原因：催芽方式的缺陷是产生上述情况的重要因素之一。

简介：Dustemissionsfromsmelters,asamajorcontributortoheavymetalcontaminationinsoils,couldseverelyinfluencesoilquality.Downwindsurfacesoilswithin1.5kmofazincsmelter,whichwasactivefor10yearsbutceasedin2000,inMaguTown,GuizhouProvince,ChinawereselectedtoexaminePb,Zn,andCdconcentrationsandtheirfractionationalongadistancegradientfromazincsmelter,andtostudythepossiblee?ectsofPb,Zn,andCdaccumulationonsoilmicroorganismsbycomparingwithareferencesoillocatedatadownwinddistanceof10kmfromthezincsmelter.Soilswithin1.5kmofthezincsmelteraccumulatedhighlevelsofheavymetalsZn(508mgkg-1),Pb(95.6mgkg-1),andCd(5.98mgkg-1)withlowratiosofZn/Cd(59.1-115)andPb/Cd(12.4-23.4).Compositepollutionindices(CPIs)ofsurfacesoils(2.52-15.2)were3to13timeshigherthanthereferencesoils.Inmetalaccumulatedsoils,exchangeablepluscarbonate-boundfractionsaccountedformorethan10%ofthetotalZn,Pb,andCd.Thesaturationdegreeofmetals(SDM)insoilswithin1.5kmofthesmelter(averaging1.25)wassixtimeshigherthanthatofthereferencesoils(0.209).Asmallersoilmicrobialbiomasswasfoundmorefrequentlyinmetalaccumulatedsoils(85.1-438μgCg-1)thaninreferencesoils(497μgCg-1),andanegativecorrelation(P<0.01)ofsoilmicrobialbiomasscarbontoorganiccarbonratio(Cmic/Corg)withSDMwasobserved.Microbialconsumptionofcarbonsourceswasmorerapidincontaminatedsoilsthaninreferencesoils,andashiftinthesubstrateutilizationpatternwasapparentandwasnegativelycorrelatedwithSDM(R=-0.773,P<0.01).Consequently,dustdepositedPb,Zn,andCdinsoilsfromzincsmeltingwerereadilymobilized,andweredetrimentaltosoilqualitymainlyinrespectofmicrobialbiomass.

简介：AsoilpotcultureexperimentwithfoursuppliedPlevels(i.e.P30,P50,P100,P200,representingsupplementalP30,50,100,200mg/kg,respectively)wasconductedtoinvestigateuptakeanduseabilitytoPandZninthericegenotypeswithdifferentP-efficiency,ofwhichricegenotypes508,99011,580,99112werelow-Ptolerantand99056,99012werelow-Psensitive.Low-Ptolerantrice580and99011absorbedmorePthantheothers,andricegenotype580hadstrongeruptakeabilityespeciallyatlow-PlevelsuchasP50andP30.508couldabsorbconsiderableP,andhadthelowestPpercentageofshoot,indicatingithadgoodperformanceinP-useefficiency.ThesethreericegenotypeshadlargerbiomassandlessresponsetochangedPlevelthanricegenotype99112,99056and99012.Ricegenotype99112showedLow-Ptolerancemainlybysacrificingbiomasstomaintainhighrelativegrainyield.TheleastamountofPabsorbedby99056showedithadthelowestPuptakeefficiency,andthehighestPpercentageinshootof99012meantithadthelowestPuseefficiency.Sotheytwoshowedlow-Psensitivity.ZncontentsinshootunderP200,P100andP50weresimilar,butP30increasedZncontentinshootsignificantly.TheZncontentsinshootof99112,99056and99012werehigherthanthoseof508,99011and580,especiallyattilleringstageandbootingstage.AsfortotalZncontentinshoot,Low-Ptolerantricegenotype580hadthelargestamountandfollowedby99011and508,low-Ptolerantricegenotype99012hadthesmallestamountatthethreesamplingstageandfollowedby99056.Furthermore,P/Zninshootof99012wasthehighest,andthatof99056wasthesmallestatthesamePlevel.

简介：在中科院长白山生态系统定位站,从地表20cm处采集土壤样品,用两种不同形式的氮肥(NO3--N,NH4+-N和NH4NO3)处理土壤样品,用盆栽试验研究了两年生红松苗木受不同浓度N源影响而产生的根际pH变化及其对根际Fe、Mn、Cu和Zn等微量元素的有效性和吸收的影响。结果表明,与对照处理相比,施加铵态氮使根际pH降低,而施加硝态氮则使根际pH增加。根际pH变化的方向与程度取决于N源及施加的浓度。根际pH的变化对根际微量元素的有效性具有显著影响,进而影响到苗木对养分的吸收利用。根际有效Fe、Mn、Cu和Zn的含量与根际pH呈负相关,而苗木叶中Fe、Mn、Cu和Zn含量与根际有效养分含量呈正相关。图5参11。

简介：针对化探样品批量大，元素多，检出限低等特点，采用水平电极撒料法，对化探样中多种微量元素进行了光谱定量分析。将样品与缓冲剂1：1混匀，采用W-100光栅摄谱仪（光栅刻线1200条，毫米，二级光谱）进行水平撒样摄谱，谱板经暗室处理后，在东德GFE760u测微光度计上用P标尺测光，以AP—logc绘制工作曲线，查出含量。本法采用了特制的撒样漏斗，改善了下料的均匀性，提高了分析精度；以Ge和Pd作内标消除工作条件变化对谱线强度的影响；同时还试选了SiO2：C：Na2SO4=61：30：9的混合物作缓冲剂，提高了弧烧的稳定性，获得了较高的再现性。本文还采用了一种单元素线减光器对Ag3382．9进行减光，使舷的测定上限由5×10-6提高到30×10-6。本法操作简便快速，成本较低，一次可测定Ag、W、Mo、Sn、Bi、Cu、Pb、Zn、Ni、Co、Cr等多种元素，检出限为Ag0．03×10-6，W0．5×10-6，Mo0．05×10-4，Sn0．4×100-6，Ph1×10-6，Zn3×10-6，Cu0．5×10-6，Bi0．1×10-6，Ni0．3×10-6，Co0．3×10-6，Cr1×10-6，基本上达到了化探普查找矿定量分析的要求。