Response of “Kalllmata” Olive Cultivar to The Foliar Application of Moringa Extract, Boron, and Zinc

This study was conducted at Wady El Natron, Beheira Governorate, Egypt through three successive seasons from 2019 to 2021, to examine the role of the foliar spraying of Moringa leaf extract (MLE) at 2000, 4000, 6000 ppm, Boric acid (H₃BO₃) at 250, 500, 1000 ppm, Zinc (Zn SO₄) at 250, 500, 1000 ppm, Combination 1: 2000 ppm MLA + 250 ppm H₃BO₃ + 250 ZnSO_4, Combination 2:  4000 ppm MLA + 500 ppm H₃BO₃ + 500 ZnSO₄, Combination 3: 6000 ppm MLA + 1000 ppm H₃BO₃ + 1000 ZnSO₄ on vegetative growth, fruit yield, oil yield and fruit quality of ten-year-old olive (Olea europaea) cv. Kalamata. The trees were planted at a distance of 6 × 5 m in sandy soil under a drip irrigation system.  Sixty-five uniform trees of the same growth and size were randomly chosen, arranged in a randomized complete block design (RCBD), and subjected to the same applied agricultural practices in the field during the three seasons. The trees were sprayed three times i.e., at the start of the season (April), at full bloom (mid of May) and three weeks later by the following treatments Control, Moringa Leaf Aqueous (MLAE) at 2000, 4000, and 6000 ppm. The results showed that the foliar application of moringa, zinc and boron solely or in combination improved greatly the leaf chlorophyll content, the number of flowers per m², fruit set % and the leaf content from nitrogen, phosphorous, potassium, zinc and boron and the most obvious effect was noticed with the spraying of combination 3 or combination 2 over control or the rest applied treatments in both experimental seasons. Additionally, it was clear from the shown data that moringa at 6000 or 4000 ppm, and zinc sulfate at 1000 were more effective in improving the same measured parameters over the rest applied treatments in both experimental seasons. The influence of 1000 ppm from zinc or born in olive trees was higher than the effect of 500 or 250 ppm from these elements during study seasons