Approach for minimizing the amount of mineral fertilizers for manfaloty pomegranate trees using mycorrhiza and yeast extract

الملخص EN

A field experiment was carried out on 6-year-old Manfaloty pomegranate trees grown in sandy soil at 3 × 5 m under drip irrigation system in Abo-Hamad Distrect, Sharkia Governorate, Egypt, during the two successive seasons of 2015 and 2016.

Thirty-three trees were subjected to 11 mineral fertilization treatments with or without mycorrhiza or yeast extract.

Control trees fertigated by 100% mineral NPK without mycorrhiza or yeast extract addition.

Other combinations 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, while mycorrhiza was applied to the soil in the wet region under the drippers at the first season (late of February) in the two seasons.

The obtained results showed that the highest yield (38.85 and 24.76 kg/tree), average fruit weight (462.70 and 462.10 g), fruit firmness (759.90 and 765.50 g/cm2 ), number of grains/fruit (630.70 and 484.20 grain) and grains weight (227.70 and 213.50 g) were gained by trees fertilized by 25 % mineral NPK + 30 g mycorrhiza/tree in the both seasons, respectively.

The produced fruits on trees of this treatment contained higher TSS/acid ratio and total anthocyanin content.

The trees fertilized by 75% mineral NPK + 30 g mycorrhiza / tree exhibited higher fruit retention percentages (92.34 and 88.70%) in the two seasons, respectively without significant differences 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 study showed that it is possible to saving 50 - 75% of mineral fertilizers with obtaining higher yields with better fruit quality by adding the mycorrhiza at 30 g/tree.