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.

Malus domestica; mineral nutrition; Fe; Cu; B

Published by University of Zagreb, Faculty of Agriculture, Zagreb, CROATIA
Sponsored by Ministry Science and Education of the Republic of Croatia