Evaluation of seasonal nutrient status in the leaves of different olive varieties grown on calcareous soils

Abstract: The study was conducted for two successive years at a private farm in El-Saf, Giza, Egypt on 19 years old trees of olive cultivars, Picual, Aggizi and Manzanillo, grown in calcareous soils. Leaf nutrients were measured bi-monthly during the 2001-2002 growing season. The study revealed that most of nutrients in the soil were at inadequate level. Nutrient concentrations in the leaves of the three cultivars were nearly the same. Results revealed that leaf N ranged between low to satisfactory. P contents were adequate in spring while inadequate in summer. K leaf contents were adequate. Peaks of Mg were found to be the highest during winter. Ca peaks were observed during March-June. Fe and Zn were inadequate while Mn was adequate. The concentrations of Fe, Mn and Zn peaked during June, which could be due the repeated foliar application of these nutrients during this period. The seasonal nutrient changes (N, P, K, Ca, Mg, Fe, Mn, Zn and Cu) of the olive leaves are supposed to be used as a guide for proper fertilization. Nutrients should be added as acidic fertilizer to the soil, which is useful in calcareous and high pH conditions.