牧草含水率测定标准(ASAE)

STANDARDASABEisaprofessionalandtechnicalorganization,ofmembersworldwide,whoarededicatedtoadvancementofengineeringapplicabletoagricultural,food,andbiologicalsystems.ASABEStandardsareconsensusdocumentsdevelopedandadoptedbytheAmericanSocietyofAgriculturalandBiologicalEngineerstomeetstandardizationneedswithinthescopeoftheSociety;principallyagriculturalfieldequipment,farmsteadequipment,structures,soilandwaterresourcemanagement,turfandlandscapeequipment,forestengineering,foodandprocessengineering,electricpowerapplications,plantandanimalenvironment,andwastemanagement.NOTE:ASABEStandards,EngineeringPractices,andDataareinformationalandadvisoryonly.Theirusebyanyoneengagedinindustryortradeisentirelyvoluntary.TheASABEassumesnoresponsibilityforresultsattrib-utabletotheapplicationofASABEStandards,EngineeringPractices,andData.Conformitydoesnotensurecompliancewithapplicableordinances,lawsandregulations.Prospectiveusersareresponsibleforprotectingthemselvesagainstliabilityforinfringementofpatents.ASABEStandards,EngineeringPractices,andDatainitiallyapprovedpriortothesocietynamechangeinJulyof2005aredesignatedas‘ASAE’,regardlessoftherevisionapprovaldate.NewlydevelopedStandards,EngineeringPracticesandDataapprovedafterJulyof2005aredesignatedas‘ASABE’.Standardsdesignatedas‘ANSI’areAmericanNationalStandardsasareallISOadoptionspublishedbyASABE.AdoptionasanAmericanNationalStandardrequiresverificationbyANSIthattherequirementsfordueprocess,consensus,andothercriteriaforapprovalhavebeenmetbyASABE.Consensusisestablishedwhen,inthejudgmentoftheANSIBoardofStandardsReview,substantialagreementhasbeenreachedbydirectlyandmateriallyaffectedinterests.Substantialagreementmeansmuchmorethanasimplemajority,butnotnecessarilyunanimity.Consensusrequiresthatallviewsandobjectionsbeconsidered,andthataconcertedeffortbemadetowardtheirresolution.CAUTIONNOTICE:ASABEandANSIstandardsmayberevisedorwithdrawnatanytime.Additionally,proceduresofASABErequirethatactionbetakenperiodicallytoreaffirm,revise,orwithdraweachstandard.CopyrightAmericanSocietyofAgriculturalandBiologicalEngineers.Allrightsreserved.ASABE,2950NilesRoad,St.Joseph,MI49085-9659,USAph.269-429-0300,fax[phone],[e-mail]358.2DEC1988(R2008)MoistureMeasurement—ForagesASAES358.2DEC1988(R2008)MoistureMeasurement—ForagesDevelopedbytheASAEPhysicalPropertiesofAgriculturalProductsCommittee;approvedbyElectricPowerandProcessingDivisionStandardsCommittee;adoptedDecember1972;reconfirmedDecember1977;revisedApril1979;reconfirmedDecember1983;revisedbythePhysicalPropertiesofAgriculturalProductsCommittee;approvedbytheFoodandProcessEngineeringInstituteStandardsCommitteeDecember1988;reaffirmedDecember1993,December1998,December1999,February2003,February2008,revisededitoriallyFebruary2008.Keywords:Forages,Moisture1Purposeandscope1.1ThisStandardestablishesuniformmethodologyforestimatingthemoisturecontentofforagematerialsinvariousforms.Othertechniques,suchasKarlFischertitrationandtoluenedistillation,shouldbeusedformoreaccuratemoisturedetermination.1.2SpecificationofsamplingproceduresisnotwithinthescopeoftheStandard.Itisassumedthattheportionofacollectedsampleusedformoisturecontentdeterminationisrepresentativeoftheentiresample.Asampledriedattemperaturesabove65°Cwillbeoflimitedvalueforsubsequentchemicalanalysis.2Apparatus2.1Samplecontainers.Samplecontainerscanbeoneoftwotypesdependingonthetimingoftheinitialweightreading.2.1.1Nonhygroscopic,moistureproofcontainerscanbeusedtoholdsamplesprovidedthevolumeofcontainedairisminimizedandcoversfittightly.Beforeuse,drythecontainerforonehouratthedryingtemperatureandobtainthetareweight.2.1.2Permeablecontainers,i.e.,clothorpaperbags,canbeusedprovidedtheinitialsampleweightistakenimmediately.Becausethesecontainersmaychangeweightwhenthesampleisovendried,asmallerrormayoccurduetochangesintareweight.Thiscanbeovercomebyovendryingthesamplecontainerandstoringitinamoistureproofcontainer,i.e.,plasticbag,untilthesampleisaddedandimmediatelyweighingthewetsampleanddrycontainer.2.2Desiccator.Ifweightreadingscannotbetakenimmediatelyattheendofthedryingperiod,thenplacethesampleinadesiccator.Thedesiccatorshouldbeairtightandshouldcontainasufficientexposureofsuitabledesiccanttoquicklylowertherelativehumidityofitsatmosphereafterloading.2.3Dryingoven.Thedryingovenmustbeproperlyventilated(mechanicalconvectionpreferred)andmusthavetemperaturesensitivityanduniformityspecificationsbetterthan62°C,intherangeof50to150°C.2.4Balance.Weighingsshouldbemadetoabout0.001ofthetotalsampleweight.A25gsampleshouldbeweighedwithabalancetothenearest0.01g.3Procedure3.1Weighthesamplecontainer.3.2Selectarepresentativesampleofatleast25g.Itisnotnecessarytochoporgrindtheselectedsamplesexceptinthecaseofcompactedforageproducts(e.g.,cubesandwafers)whichshouldbereducedinsizewithoutmoisturelosssothatatleastonedimensionofaparticleislessthan15mm.3.3Placethesampleinthesamplecontainer.3.4Weighthesamplecontainerplussample.3.5Placethesamplecontainerplussampleinthedryingoven.Coversmustberemovedwhilethesampleisbeingdriedintheoven.3.6Drythesampleintheoven.3.