Nitrogenousfertilisersareunderconsiderationforpromotingthegrowthofnursery-rearedhooppine(AraucariacunninghamiiAitonexA.Cunn)seedlingsintheestablishmentphaseofsecondrotation(2R)plantations.Using15N-labelledfertilisers,weinvestigatedtheeffectofdifferentforms(ammoniumsulphate,ammoniumnitrate,potassiumnitrateandurea)andratesofapplication(0,150and300mgNkg-1driedsoil)offertilisersonthegrowth,15Nrecoveryandcarbonisotopecomposition(δ13C)ofhooppineseedlingsina12-monthglasshousetrialinsoutheastQueensland,Australia.The15N-labelledfertiliserswereappliedtonursery-rearedhooppineseedlings,whichwerethengrowninpots,containingca.1.2kgdriedsoil,underwellwateredconditionsfor12months.Fourseedlingsfromeachtreatmentwereharvestedat4-monthintervals,pidedintoroots,stemandfoliage,withafurthersubpisionfornewandoldfoliage,andthenanalysedfor15N,totalN,δ13CandtotalC.Therewasnosignificantresponseintheseedlinggrowthtotheformorrateofapplicationofnitrogen(N)fertiliserwithinthe12-monthperiod,indicatingthattheseedlingsdidnotexperienceNdeficiencywhengrownonsecondrotationhooppinesoils.Whilethecombined15Nrecoveryfromsoilandplantremainedataround70%throughouttheexperiment,theproportionof15Nrecoveredfromtheplantsincreasingsteadilyovertime.Nitratecontainingfertilisersat150mgNkg-1soilgraduallyincreasedseedlingfoliageδ13Coverthe12-monthperiod,indicatinganincreaseinseedlingwateruseefficiency.
