APPROACH FOR MINIMIZING THE AMOUNT OF MINERAL FERTILIZERS FOR MANFALOTY POMEGRANATE TREES USING MYCORRHIZA AND YEAST EXTRACT

Abstract

A field experiment was carried out on 6-year-old Manfaloty pomegranate treesgrown in sandy soil at 3 × 5 m under drip irrigation system in Abo-Hamad Distrect, SharkiaGovernorate, Egypt, during the two successive seasons of 2015 and 2016. Thirty-three trees weresubjected to 11 mineral fertilization treatments with or without mycorrhiza or yeast extract. Controltrees fertigated by 100% mineral NPK without mycorrhiza or yeast extract addition. Othercombinations were 75, 50 and 25% mineral NPK with or without 30 g mycorrhiza or yeast extract.The mineral fertilizer and died yeast applied by fertigation in ten doses during the season, whilemycorrhiza was applied to the soil in the wet region under the drippers at the first season (late ofFebruary) in the two seasons. The obtained results showed that the highest yield (38.85 and 24.76kg/tree), average fruit weight (462.70 and 462.10 g), fruit firmness (759.90 and 765.50 g/cm2), numberof grains/fruit (630.70 and 484.20 grain) and grains weight (227.70 and 213.50 g) were gained by treesfertilized by 25 % mineral NPK + 30 g mycorrhiza/tree in the both seasons, respectively. Theproduced fruits on trees of this treatment contained higher TSS/acid ratio and total anthocyanincontent. The trees fertilized by 75% mineral NPK + 30 g mycorrhiza / tree exhibited higher fruitretention percentages (92.34 and 88.70%) in the two seasons, respectively without significantdifferences between them in most cases. Leaves of trees fertigated by 100% mineral/tree (control)contained the highest values of N, P, K, Ca and Mg in the both seasons. The results of this studyshowed that it is possible to saving 50 - 75% of mineral fertilizers with obtaining higher yieldswith better fruit quality by adding the mycorrhiza at 30 g/tree.