ExperimentswerecarriedoutonavegetablefieldwithPekingcabbage(Brassicapekinensis(Lour.)Rupr.),cabbage(Brassicachinensisvar.OleiferaMakinoandnemoto),greencabbage(BrassicachinensisL.),spinach(SpinaciaoleraceaL.)andrape(BrassicacampestrisL.)tostudytheeffectsofNformsandNratesontheirgrowthandnitrateaccumulation.Theresultsindicatedthatapplicationofammoniumchloride,ammoniumnitrate,sodiumnitrateandureasignificantlyincreasedtheyieldsandnitrateconcentrationsofPekingcabbageandspinach.Althoughnosignificantdifferencewasfoundintheyieldsafterapplicationofthe4Nforms,nitrateNincreasednitrateaccumulationinvegetablesmuchmorethanammoniumN.ThevegetableyieldswerenotincreasedcontinuouslywithNrateincrease,andoversupplyofNreducedtheplantgrowth,leadingtoayielddecline.Thistrendwasalsotruefornitrateconcentrationsinsomevegetablesandatsomesamplingtimes.However,asawhole,thenitrateconcentrationsinvegetableswerepositivelycorrelatedwithNrates.Thus,additionofNfertilizertosoilwasthemajorcauseforincreasesinnitrateconcentrationsinvegetables.Nitrateconcentrationsweremuchhigherinroots,stemsandpetiolesthaninbladesatanyNrate.
