THE FATE OF CALCIUM APPLIED THROUGH FOLIAR FERTILIZATION ON OLEA EUROPEAE L.

Abstract

Olive trees fertilization through foliar pulverization is a more targeted oriented method than the application of chemical fertilizers to the soil. Many factors influence the performance of foliar nutrients sprays such as the presence of leaf cuticle, leaf hairs and leaf surface wax. Calcium is one of the most common macronutrients applied as foliar fertilizer due to its low mobility inside the plants. The presence of calcium in olive fruits, mainly in cell walls, will improve resistance to important pest problems as well as improve fruit quality. The aim of this study was the evaluation in ‘Galega vulgar’ olive trees the efficacy of calcium foliar applications and the subsequent redistribution of this nutrient through the different cell components. Olive trees were sprayed four times from August until veraison with a commercial product containing 34% of calcium, in three different doses. Our results confirmed that calcium applied through foliar pulverization increased calcium deposition in fruit cell wall as well as the total calcium in the fruits. It is also discussed the role of epidermal structures, the hydrophobicity of leaves surface and the presence of cuticle waxes, in the absorption of foliar-applied calcium.