EFFECT OF CALCIUM CHLORIDE SPRAYS AT DIFFERENT WATER VOLUMES ON “SZAMPION” APPLE CALCIUM CONCENTRATION

The aim of the study was to examine the effect of calcium chloride sprays at different water volumes on ‘Szampion’ apple calcium (Ca) concentration. Apple trees were sprayed with CaCl₂at a rate of 7 kg ha^?1 using 250, 500, 1000, and 1500 L of water which represents: 2.8, 1.4, 0.7 and 0.5% CaCl₂ solution, respectively. Sprays with CaCl₂ were applied 6, 4, and 2 weeks before fruit harvest by a directed air-jet sprayer with radial fan. Fruit Ca concentrations were determined from the bottom (to 1.5 m height), middle (from 1.6 to 2.3 m height) and top (from 2.4 to 3.0 m height) of tree. The trees unsprayed with Ca served as a control. The study showed that such treatments did not injure leaves and fruit. Efficacy of CaCl₂ sprays at studied water rates in increasing fruit Ca concentration was similar. Apples sprayed with Ca from the middle and bottom of tree canopy had higher Ca concentrations than control fruit. Leaf Ca applications at all water volumes had no effect on fruit Ca concentration from tree canopy top, however, laboratory study indicated that apples from this zone had ability to take up exogenous Ca. It was also found that young ‘Szampion’ fruitlets took up clearly less exogenous Ca as compared to mature fruit, which suggests that Ca sprays of this cultivar should be performed mainly at late apple development stages.