简介：土壤体积密度的测量为理解土壤的物理、化学、生物的性质是重要的。精确、快速的土壤体积密度测量技术在农业试验性的研究起一个重要作用。这评论是存在测量方法的一篇全面摘要并且为未来开发评估他们的优点，劣势，错误的潜在的来源，和方向。这些技术能广泛地作为直接、间接的方法被分类。直接方法包括核心，土块，和挖掘采样，而间接方法包括放射和回归途径。核心方法最广泛地被使用，但是为采样使用多重土壤深度耗时、困难。coring柱体的尺寸使用了，操作员经验，采样深度，并且在原处显著地玷污潮湿内容影响它的精确性。土块方法是合适的因为有重黏土的使用，和它的精确性依赖于设备刻度，弄干时间，和操作员经验，但是这个过程复杂、耗时。挖掘技术最通常被用来评估森林土壤的体积密度，但是把他们不能与大毛孔在土壤被使用，他们的测量精确性被土壤质地和分析的类型强烈影响的主要限制选择。间接方法看起来比直接途径有更大的精确性，但是有更高的费用，是更复杂的，并且要求更大的操作员经验。一如此的途径使用gamma放射，和它的精确性被土壤深度强烈影响。当他们能做间接大小，回归方法是节俭的，但是这些取决于土壤质地和有机物内容和地理、气候的性质的好、优秀数据。另外，它的精确性象大多数另外的途径一样，与采样深度减少。

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简介：农业土地的放弃为生态系统导致所在地、远距离的后果。在这研究，105降雨模拟在西班牙在地中海带的农业陆地被执行(在M的葡萄园

简介：Determiningthephysicalandmechanicalpropertiesofsoilanditsbehaviorforengineeringprojectsisessentialforroadconstructionoperations.Oneofthemostimportantprinciplesinforestroadconstruction,whichisusuallyneglected,istoavoidmixingorganicmatterwithroadmaterialsduringexcavationandembankmentconstruction.Thecurrentstudyaimedtoassesstheinfluenceoforganicmatteronthephysicalpropertiesandmechanicalbehaviorsofforestsoilandtoanalyzetherelationbetweentheamountoforganicmatterandthebehaviorofforestsoilasroadmaterial.Atypicalsoilsamplefromthestudyareawascollectedbesideanewlyconstructedroadbed.Thesoilwasmixedwithdifferentpercentagesoforganicmatter(controltreatment,5,10,and15%bymass)anddifferenttestsincludingAtterberglimits,standardcompaction,andCaliforniabearingratio(CBR)testswereconductedonthesedifferentsoilmixtures.Theresultsshowedthatsoilplasticityincreasedlinearlywithincreasingorganicmatter.Increasingtheorganicmatterfrom0%(control)to15%resultedinanincreaseof11.64%oftheplasticlimitand15.22%oftheliquidlimitafterdryingat110℃.Also,increasingtheorganicmattercontentreducedthesoilmaximumdrydensityandincreasedtheoptimummoisturecontent.Increasingtheorganicmatterfrom0to15%resultedinanincreaseof11.0%oftheoptimummoisturecontentandadecreaseof0.29g/cm3ofthemaximumdrydensity.OrganicmatterdecreasedtheCBR,whichisusedastheindexofroadstrength.Adding15%organicmattertothesoilresultedinadecreaseoftheCBRfrom15.72to4.75%.Therewasasignificantdifferencebetweenthetwodryingtemperatures(60and110℃)forthesameorganicmattermixtureswithlowerwatercontentvaluesafterdryingat60℃.Theresultsrevealedtheadverseinfluenceoforganicmatteronsoilengineeringpropertiesandshowedtheimportanceoforganicmatterremovalbeforeexcavationandfillconstruction.

简介：这评论在三种尺寸在流量和土壤损失上总结植被的效果：垂直植被结构(未葬植被盖子，表面崽层和地下的根)，植物差异，植被模式和他们的规模特征。在有流量和土壤损失的植被因素之间的量的关系被描述。为描述包含植被，侵蚀和规模的关系的一个框架被建议。为各种各样的侵蚀过程的每种植被尺寸的相对重要性越过规模变化。与侵蚀特征的发展(即，骚动，interrill，小河和溪谷)，在控制流量和土壤损失的垂直植被结构的主要因素变化从未葬生物资源到根。植物差异层次与垂直植被结构被相关并且当植被模式也越过规模维持批评功能时，在小规模起一个关键作用(即，补丁，斜坡，集水和盆/区域)。为未来学习的几个话题在这评论被建议，例如为生态的恢复决定有效植被体系结构，以考虑植被模式的动力学，并且识别包含植被的三种尺寸的相互作用。

简介：Thisstudyinvestigatestheeffectsofincreasingsoilpenetrationresistance(SPR)onseedlingmorphologyandseedlingarchitecture.WhenseedlingsofdeciduousCappadocianmaple(AcercappadocicumGled.)weregrowninagreenhouseinaloamysoilunderawiderangeofsoilcompactions,allmorphologicalvariablesstudiedchangedsignificantlywithincreasingSPR.TherelationshipsbetweenincreasingSPRandallmorphologicalresponsesexceptlateralrootlengthfollowedanegativequadraticcurve.Allbiomassvariablesexceptlateralrootbiomassshowedabell-shapedresponsewithrespecttoSPR,withamaximumbiomassvariablebetween0.6and1.2MPa,decreasingathighersoilcompactionvalues.Allallocationratiosweresignificantlyaffectedbysoilpenetrationresistance.Biomassallocationtorootswasalsoaffectedbysoilcompaction.Therewasnotasignificantrelationshipbetweenthespecificstemlengthandincreasingsoilpenetrationresistance.ThespecificrootlengthshowedtwotrendstoincreasingSPR;itfirstdecreasedinresponsetothemoderatecompactiontreatment(uptoabout1.2MPa),thenincreasedsignificantly.WeconcludedthatincreasingsoilcompactioncausedmorphologicalchangestorootandshootsectionsofA.cappadocicumseedlings.

简介：Inthispaper,weusetheinterflowareaastheresearchobjectinthelogicalscienceparkforsoilandwaterconservationinJiangxiprovince;andthePaspalumnatatumanditslittercoverareusedasthegroundflora.WediscussesandanalysestheverticaldistributionofrunoffsoastoprovidetheoreticalsupportforthewideapplicationofthePaspalumnatatumforsoilandwaterconservationintheregionofredsoilinsouthChina.

简介：Weconductedastudytofindoutifarbuscularmycorrhizal(AM)fungi(Acaulosporascrobiculata,Scutellosporacalospora)andphosphatesolubilizingbacteria(PSB,Paenibacilluspolymyxa)inoculationeitherindividuallyorincombinationscanimproveAcaciaauriculiformisseedlinggrowth,uptakeofnutrientsandqualityinaphosphorusdeficienttropicalAlfisol.Theseedlingswereassessedforvariousgrowthandnutrientuptakeparametersafter60daysoftreatment.InoculationwithP.polymyxastimulatedmycorrhizalformation.Seedlingheight,stemgirth,taprootlength,numberofleavesandleafarea,plantdrymatterproduction,nodulation,andnodulardryweightweresignificantlyhigherforseedlingsthatwereeitherdualinoculatedortripleinoculatedcomparedtoindividualinoculationofAMfungiorPSB,anduninoculatedseedlings.DualandtripleapplicationofAMfungiandPSBalsosignificantlyimprovedthenutrientcontentsofshootsandrootsandnutrientuptakeefficiencies.ThecalculatedseedlingqualityindexesoftheAMfungiandPSBinoculatedseedlingwere25–208%higherthanuninoculatedseedlings.ThesefindingsshowthatA.auriculiformisseedlingswhendualinoculatedortripleinoculatedperformedbetterthanseedlingsinoculatedwiththemicrobesindividuallyandcomparedwithuninoculatedcontrolseedlings.Weconcludethatbioinoculationisimportantfortheproductionofhigh-qualityA.auriculiformisseedlingsintreenurseriesforplantinginnutrientdeficientsoils.

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简介：Thedynamicshearmodulusratioanddampingratioofsandygravelareimportantparametersfortheseismicresponseanalysisofvalleygeomorphicsites,whichhaveanimportantimpactonthedeterminationofdesigngroundmotionparameters.Inthispaper,thedynamictriaxialtestofsandygravelshasbeenperformedbasedontheprojectoftheShangluoSeismicMicrozonation.Combinedwiththeotherresultsofsandygravel,therecommendedresultsofslightlydense,mediumdenseanddensesandygravelwereobtained.Bybuildingthetypicalsitemodel,theinfluenceofthedynamicshearmodulusratioandthedampingratiouncertaintyontheseismicresponseofthesiteisstudied.Theresultsshowthattheuncertaintyoftheaverageofthedynamicshearmodulusratioandthedampingratio±1timesthestandarddeviationhaslittleeffectonthepeakaccelerationofthesandygravelsite,andtherationalityofthegroupingandstatisticalresultsisexplained.Underdifferentprobabilitylevels,thechangeintheshearmodulusratioanddampingratioleadstoasignificantdifferenceinthehighfrequencyresponsespectrum.Theresponsespectrumof0.04-0.1srangesfromabout20%,butithaslittleeffectonthelongperiodspectrumofmorethan1.0s.Thestudyofdynamicshearmodulusratioanddampingratioofsandygravelhastheabilitytoimprovethereliabilityofthedesigninggroundmotionparameters.

简介：Thepenetrationdepthoftorpedoanchorintwo-layeredsoilbedwasexperimentallyinvestigated.Atotalof177experimentaldatawereobtainedinlaboratorybyvaryingtheundrainedshearstrengthofthetwo-layeredsoilandthethicknessofthetopsoillayer.Thegeometricparametersoftheanchorandthesoilproperties(theliquidlimit,plasticlimit,specificgravity,undrainedshearstrength,density,andwatercontent)weremeasured.Basedontheenergyanalysisandpresenttestdata,anempiricalformulatopredictthepenetrationdepthoftorpedoanchorintwo-layeredsoilbedwasproposed.Theproposedformulawasextensivelyvalidatedbylaboratoryandfielddataofpreviousresearchers.Theresultswereingoodagreementwiththoseobtainedfortwo-layeredandsingle-layeredsoilbed.Finally,asensitivityanalysisontheparametersintheformulawasperformed.

简介：Background:Thelargepotentialofthesoilorganiccarbon(SOC)pooltosequesterCO2fromtheatmospherecouldgreatlyamelioratetheeffectoffutureclimatechange.However,thequantityofcarbonstoredinterrestrialsoilslargelydependsuponthemagnitudeofSOCmineralization.SOCmineralizationconstitutesanimportantpartofthecarboncycle,andisdrivenbymanybiophysicalvariables,suchastemperatureandmoisture.Methods:Soilsamplesofapineforest,anoakforest,andapineandoakmixedforestwereincubatedfor387daysunderconditionswithsixtemperaturesettings(5°C,10°C,15°C,20°C,25°C,30°C)andthreelevelsofsoilmoisturecontent(SMC,30%,60%,90%).TheinstantaneousrateofmineralizedSOCwasperiodicallyandautomaticallymeasuredusingaLi-CorCO2analyzer.BasedonthemeasuredamountofmineralizedSOC,carbonfractionswereestimatedseparatelyviafirst-orderkineticone-andtwo-compartmentmodels.Results:Duringthe387dayincubationexperiment,accumulativemineralizedcarbonrangedfrom22.89mgcarbon(C)·g-1SOCat30°Cand30%SMCforthemixedforestto109.20mgC·g-1SOCat15°Cand90%SMCfortheoakforest.Mineralizedrecalcitrantcarbonvariedfrom18.48mgC·g-1SOCat30°Cand30%SMCforthemixedforestto104.98mgC·g-1SOCat15°Cand90%SMCfortheoakforest,andcontributedatleast80%tototalmineralizedcarbon.Conclusions:Basedontheresultsofthisexperiment,thesoilorganicmatterofthepurebroadleavedforestismorevulnerabletosoilmicrobialdegradationinnorthernChina;mostoftheamountofthemineralizedSOCderivedfromtherecalcitrantcarbonpool.Labilecarbonfractionconstitutesonaverage0.4%ofSOCacrossthethreeforesttypesandwasrapidlydigestedbysoilmicrobesintheearlyincubationstage.SOCmineralizationmarkedlyincreasedwithsoilmoisturecontent,andcorrelatedparabolicallytotemperaturewiththehighestvalueat15°C.Nosignificantinteractionwasdetectedamongthese

简介：土壤腐殖的碳是土壤的一个重要部件在陆上的生态系统的器官的碳(SOC)。然而，到日期的学习都没调查它的地理模式和在大规模影响它的主要因素，尽管它为在土壤C存储和周转上探索气候变化的影响是批评的。我们测量了SOC的层次，腐殖的酸碳(HAC)，fulvic酸碳(FAC)，humin碳(HUC)，并且在沿着3800-km的九个典型森林里的0-10厘米土壤层的可引出的腐植质碳(HEC)东方中国(NSTEC)的纵贯的横断阐明土壤的纬度的模式腐殖的碳部分和他们的主要影响因素。SOC，HAC，FAC，HUC，和HEC与增加纬度增加了(所有P<0.001)，并且展出了一个一般趋势热带<副热带<适度。到SOC的腐殖的C部分的比率是9.48%-12.27%(HAC)，20.68%-29.31%(FAC)，和59.37%-61.38%(HUC)。气候，土壤质地，和土壤微生物联合在SOC，HAC，FAC，HEC，和HUC解释了超过90%纬度的变化，并且交互效果是重要的。这些调查结果阐明纬度的模式在大规模在森林里玷污腐殖的C部分，并且可以改进土壤C周转和存储的模型。

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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：Prescribedfireisacommoneconomicalandeffectiveforestrypractice,andthereforeitisimportanttounderstandtheeffectsoffireonsoilpropertiesforbettersoilmanagement.Weinvestigatedtheimpactsoflow-intensityprescribedfireonthemicrobialandchemicalpropertiesofthetopsoilinaHungarianoak(QuercusfrainettoTen.)forest.Theresearchfocusedonmicrobialsoilparameters(microbialsoilrespiration(RSM),soilmicrobialbiomasscarbon(Cmic)andmetabolicquotient(qCO2)andchemicaltopsoilproperties(soilacidity(pH),electricalconductivity(EC),carbon(C),nitrogen(N),C/Nratioandexchangeablecations).Meanannualcomparisonsshowsignificantdifferencesinfourparameters(C/Nratio,soilpH,CmicandqCO2)whilemonthlycomparisonsdonotrevealanysignificantdifferences.SoilpHincreasedslightlyintheburnedplotsandhadasignificantlypositivecorrelationwithexchangeablecationsMg,Ca,MnandK.ThemeanannualC/Nratiowassignificantlyhigherintheburnedplots(28.5:1)thaninthecontrolplots(27.0:1).ThemeanannualCmic(0.6mgg-1)wassignificantlyloweralthoughqCO2(2.5lgCO2–CmgCmich-1)wassignificantlyhigher,likelyresultingfromthemicrobialresponsetofire-inducedenvironmentalstress.Low-intensityprescribedfirecausedveryshort-livedchanges.TheannualmeanvaluesofC/Nratio,pH,CmicandqCO2showedsignificantdifferences.

简介：土壤drying-rewetting(DRW)事件影响滋养的转变和微生物引起的社区作文；然而，很少对在DRW事件期间弄干紧张的影响被知道。因此，我们在一个试验性的drying-rewetting事件期间与暴露分析了土壤营养素作文和微生物引起的社区到各种各样的弄干的紧张，用从北中国的一块草地的淤泥沃土，在半干旱的气候暴露土壤到大量潮湿条件的地方，并且草地占超过40%国家陆地区域。我们也进行了一个消毒实验检验土壤微生物的贡献到滋养的脉搏。土壤drying-rewetting减少了由9%-27%的碳(C)矿化作用。monosaccharide和矿物质氮(N)内容与更高弄干紧张增加了(弄干到10%gravimetric水内容)，与最高的弄干紧张随增加是204%和110%(弄干到2%gravimetric水内容)，分别地而易变的磷(P)仅仅增加了(在105%)与最高的弄干紧张。而且，微生物引起的生物资源C和N和溶解器官的N的层次与增加弄干紧张减少了并且分别地，而易变的P的增加不与在微生物引起的生物资源P的减小一致，随溶解器官的C和矿物质N的增加被相关。消毒实验结果显示微生物为C和N脉搏主要负责，而非微生物引起的因素是到易变的P脉搏的主要贡献者。Phospholipid丰满的酸分析显示土壤微生物对drying-rewetting事件高度抵抗并且干旱抵抗的组为滋养的转变可能负责。因此，现在的学习证明在drying-rewetting事件期间弄干的中等土壤能改进N，然而并非P的矿化作用，并且不同机制为C，N，和P脉搏负责，这在drying-rewetting期间观察了事件。

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简介：Elevatedatmosphericnitrogen(N)depositionhasbeendetectedinmanyregionsofChina,butitseffectsonsoilNtransformationintemperateforestecosystemsarenotwellknown.WethereforesimulatedNdepositionwithfourlevelsofNadditionrate(N0,N30,N60,andN120)for6yearsinanold-growthtemperateforestinXiaoxing’anMountainsinNortheasternChina.WemeasuredgrossNtransformationratesinthelaboratoryusing15NtracingtechnologytoexploretheeffectsofNdepositiononsoilgrossNtransformationstakingadvantageofNdepositionsoils.NosignificantdifferencesingrosssoilNtransformationrateswereobservedafter6yearsofNdepositionwithvariouslevelsofNadditionrate.ForallNdepositionsoils,thegrossNH4+immobilizationrateswereconsistentlylowerthanthegrossNmineralizationrates,leadingtonetNmineralization.Nitrate(NO3-)wasprimarilyproducedviaoxidationofNH4+(i.e.,autotrophicnitrification),whereasoxidationoforganicN(i.e.,heterotrophicnitrification)wasnegligible.Differencesbetweenthequantityofammonia-oxidizingbacteriaandammonia-oxidizingarchaeawerenotsignificantforanytreatment,whichlikelyexplainsthelackofasignificanteffectongrossnitrificationrates.GrossnitrificationratesweremuchhigherthanthetotalNO3-consumptionrates,resultinginabuild-upofNO3-,whichhighlightsthehighriskofNlossesviaNO3-leachingorgaseousNemissionsfromsoils.ThisresponseisoppositethatoftypicalN-limitedtemperateforestssufferingfromNdeposition,suggestingthattheinvestigatedold-growthtemperateforestecosystemislikelytoapproachNsaturation.