FOLIAR BORON, COPPER AND MANGANESE UPTAKES AND CONCENTRATIONS OF APPLE LEAVES CV. GOLDEN DELICIOUS ON M9 AND B9 ROOTSTOCKS

Mature apple trees (Mauls domestic Borkh cv. Golden Delicious) on M9 and B9 rootstocks received foliar nutrient application with boron (B), copper (Cu) and manganese (Mn). Boric acid (H₃BO₃, 1000 mg/l), copper sulfate (CuSO₄, 500 mg/l) and manganese sulfate (MnSO₄, 1000 mg/l) were sprayed separately or in combination with each other. Foliar applications were applied three times on the same trees, in May, June and September. The experiment was carried out in a split plot design with the M9 and B9 rootstocks as main plots and eight foliar sprays as subplots. Results indicated that the foliar nutrient application significantly increased concentrations of B, Cu and Mn in the leaves. The nutrient uptake was highest when the trees were sprayed in May. Synergistic and antagonistic effects on B, Cu and Mn uptakes were seen, mainly at the front spray. Uptakes of B by M9 and Cu by B9 rootstocks were high in May and June respectively. Foliar application of Cu had longer effect, than Mn and B application. It was found that two sprays of Cu in June and September would be enough for Cu supply of apple trees while Mn and B applications should be repeated several times during the growing period.