Optimizing Gibberellic Acid and Phosphate for Apple Growth

Luay Sahib Radhi; Osama Abdul Rahman Owied  Al Kzraji

Luay Sahib Radhi Soil Sciences and Water Resources, College of Agriculture, University of Sumer, Al-Rifai, Iraq
Osama Abdul Rahman Owied Al Kzraji Department of Anatomy, Faculty of Medicine, University of Sumer, Al-Rifai, Iraq

Keywords: Gibberellic acid, Phosphate fertilization, Iraqi soils, Apple trees, Carbohydrates.

Abstract

In a private orchard in Al-Mahawil, Babil Governorate, Iraq, during the 2022-2023 growing season, apple trees were subjected to a factorial experiment involving gibberellic acid spraying at 0, 10, and 30 ml.l^-1 concentrations with two applications spaced thirty days apart, and soil fertilization with phosphate at 0, 20, 30, and 50 g.l^-1 levels with irrigation water. Results indicated that a concentration of 20 ml L^-1 gibberellic acid significantly increased chlorophyll content, carbohydrate percentage, and nutrient levels (N, P, K, Mn, and Fe) compared to other concentrations. Furthermore, soil treatment with 30 g L^-1 phosphate, combined with irrigation water, significantly impacted all studied traits except carbohydrate percentage, which was higher than the 50 g L^-1 spray treatment, registering a 37.52% rate. These findings highlight the potential of optimized gibberellic acid and phosphate application in enhancing apple tree growth and nutrient uptake, underscoring the importance of tailored fertilization strategies for orchard management and productivity optimization.

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