简介:Threegoatswerefedwith^15N-labelledricestrawtostudythecharacteristicsofdigestion,assimilation,transformationandexcretionofCandNcompoundsfromricestraw.Itwasshownthattheamountof^15Ntransformedintothebodiesofthetwoslaughteredgoatsaccountedfor38.5and23.6%ofthetotalamountof^15Ndepositionoftheexperimentaldiettakenbyeachgoat.The^15Nexcretedthroughthefecesandurineforthethreegoatsaccountedfor34.8,33.2and33.9%ofthetotalamountof^15Ndepositioninthefeedofthe3goats.Therecoveryoftotal^15Nforthetwoslaughteredgoatswere73.3and57.5%,withthecorrespondingratesof^15Nloss26.7and42.5%respectively.ThedigestibilitiesoftotalaminoacidsforGoats1and3were68.7and54.0%,andthedigestibiltiesofcarbohydratesforthetwogoatswere74.8and67.7%respectively.
简介:PotexperimentswerecarriedouttoestimateN2fixationbyvetch,milkvetch,sicklealfalfaandbroadbeaninpurestandusinga^15N-labelledsoil.Winterwheatwasusedasthenon-fixingcontrol.The15N-labelledsoilusedwaspreparedbygrowingcorn-wheat-cornsuccessivelyonanearlyorganic-matter-freeXiashuloesssupplementedwithadequateamountsof(15NH4)2SO4,P,Kandmicronutrients,thenincorporatingthese15N-labelledplantmaterialsintothesoilaftereachhavest,andallowingtheplantmaterialstobedecomposedaerobicallyfor410dafterincorporationoftheplantmaterialofthethirecrop.The15Nenrichmentofwheatplant-Nvariedslightlywithorgans,withamaximumdifferenceof9.8%,Basedon15NenrichmentofsoilNinferredfromthemeanvalueofthe15Nenrichmentindifferentorgansofwheat79%-91%oftotalNinthetopsand67%-74%oftotalNintherootsoflegumesstudiedwerederivedfromatmosphere.EstimatebyisotopedilutionmethodwasingoodagreementwiththatbytheconventionaldifferencemethodprovidedvaluesobtainedbythelatterwerecorrectedforseedN,andalsowiththatfromthemeasurementofNaccumulatedinthetopsofthelegumes.