Influence of Fertirigation With Nitrogen on Iron, Copper and Boron Content in Leaf and Cropping of ´Jonagold´ and ´Golden Delicious´ Apple Trees

Pokus je izveden s dvije sorte jabuke (Malus domestica Borkh) cijepljene na podlozi M9 i uzgajane u gustom sklopu (Jonagold 2500 stabala/ha, Golden Delicious 3000 stabala/ha). U pokusu je bilo pet tretmana (fertirigacija s 45 kg N/ha, 60 kg N/ha, 120 kg N/ha, natapanje bez gnojidbe i kontrola . bez natapanja i uporabe gnojiva), u dvije varijante (tretmani za vrijeme vegetacije: od 1. svibnja do 20. lipnja - varijanta A, i od 1. svibnja do 1. kolovoza - varijanta B). Pokus je trajao sedam godina počevši od druge godine poslije sadnje (1992-1998.). Koncentracija mikroelemenata u lišću utvrđena je tijekom sedme i osme vegetacije. Tijekom tih vegetacija zamijećeni su određeni utjecaji primijenjenih tretmana na koncentraciju mikroelemenata u lišću, ali oni nisu bili konzistentni. Utjecaj varijanti primijenjenih tretmana na koncentraciju mikroelemenata u lišću nije bio značajan. U rodnim godinama (1993-1998.) nije utvrđen konzistentan utjecaj na kumulativan i specifičan kumulativan prirod obadviju sorti jabuke. Najveći kumulativan prirod ostvarila je sorta Jonagold u kontroli, dok je sorta Golden Delicious postigla najbolje rezultate uz primjenu fertirigacije s dušikom u dozi 45 i 60 kg N/ha.Two apple (Malus domestica Borkh) cultivars grafted on M.9 rootstock were grown at high density (’Jonagold’ 2500 trees/ha, ’Golden Delicious’ 3000 trees/ha). There were five treatments for each cultivar (fertigation with 45 kg N/ha, 60 kg N/ha, 120 kg N/ha, irrigation without fertilisers, and control - without irrigation and without fertilisers), and two timing variants (treatments during vegetation period from 1 May to 20 June - variant A, and treatments from 1 May to 1 August - variant B). The treatments were impossed beginning in the second year after planting and lasted seven years (1992-1998). Concentration of microlements in leaf was determined over the 7th and 8th growing seasons. During the seasons 1997/98 effects of the applied treatments on leaf mineral content were notable, but these effects often were not consistent. There were no significant timing effect on leaf nutrient concentration of both cultivars. During the cropping years (1993-1998) there were no consistent treatment effects for cumulative yield and cumulative yield efficiency. The highest cumulative yield achieved ´Jonagold´ in the control, while ´Golden Delicious´performed best when it was fertilised with 45 and 60 kg N/ha