ISHS Acta Horticulturae 564: IV International Symposium on Mineral Nutrition of Deciduous Fruit Crops
THE EFFECTS OF BALANCED FERTILIZATION AND ZINC APPLICATION ON IMPROVING APPLE YIELD, QUALITY, AND REDUCING BROWNING INCIDENCE |
| Author: | M.J. Malakouti |
| Keywords: | deep placement, apple fruit, pollination, firmness, micronutrient, chlorophyll density and stress analysis |
| Abstract:
Two apple orchards (‘Red Delicious’ and ‘Golden Delicious’, (Malus domestica Borkh.) with calcareous soils in five different regions of Iran, i.e. Damavand, Chenaran, Semirom, Maragheh, and Qruomieh regions were selected in March 1998. Each fertilizer treatment was tested in five plots, each plot containing one apple tree. The fertilizer treatments were T1 (Check plots), T2 (Foliar application, fruit–set), T3 (Foliar application of calcium chloride), T4 (Placement of macro and micronutrients in holes dug around the trees), T5 (Foliar application of macro and micronutrients), T6 (A combination of T3, T4, and T5), and T7 (Broadcast application of macro and micronutrients). The chemical fertilizers were mixed with animal manure. In treatment T5, foliar spray of 0.7% solution of macro and micronutrients were carried out four times. The concentrations of macro in the solution were 0.15%. These concentrations were reduced by 50% with the third and fourth applications because the higher concentration caused burning of the leaf edges. Leaf and fruit samples were collected and analyzed for nutrients. Chlorophyll density and stress analysis were also performed. The results demonstrated that a significant difference in the yield of apple at 1-% level was observed due to balanced fertilization. Fruit texture improved significantly as a result of the spray application of calcium chloride. The best result was obtained with a 0.7% solution of calcium chloride during fruit development. Combining the placement of zinc sulfate in holes at the foot of the trees with foliar applications increased the concentration of zinc from 0.7 to 1.5 mg per kg of apple. Due to increase in the activities of enzymes such as Dismutase super oxidase and the role of zinc as an antioxidant, the browning of the treated apples was reduced. | |
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