Effect of organic fertilizer and amino acids on the vegetative growth of young pomegranate trees Punica granatum L. c.v. “Wonderful”

Abstract

The experiment was conducted on a pomegranate field located in a deciduous fruit orchard at the Agricultural Research and Experimentation Station, which is associated with the College of Agriculture at the University of Kirkuk in the Republic of Iraq. The experiment took place during the 2023 season. The study incorporated 2 variables. The experiment consisted of 2 factors: the first factor included 5 levels of organic fertilization (0, 250 and 500 g tree-1 of residue poultry and 15 and 30 g tree-1 of humic acid) and the second factor involved spraying with 3 concentrations of amino acids (0-, 5- and 10- mL L-1). The experimental design used was a Randomized Complete Block Design (RCBD) within factorial experiments, with 2 factors and 3 replicates. The study involved a total of 90 young pomegranate trees, with 2 trees assigned to each experimental unit. The data were analyzed using Duncan's multinomial test at a significance level of 0.05. Applying 500 g of chicken waste per tree resulted in a notable enhancement in vegetative development, namely in stem length. The leaf area and dry weight of the leaves were measured at 6.45 cm2 and 54.67 % respectively. The level of 30 g tree-1 of humic acid resulted in a significant increase in the stem diameter, branch length and branch diameter, which was recorded at 23.16 mm, 39.98 cm and 6.30 mm respectively, compared to the control treatment. The application of a 10 mL L-1 concentration of amino acids led to a notable enhancement in the observed traits (stem length and branches, their diameters, leaf area and dry weight of leaves) in comparison to the control treatment. The mutual influence of organic fertilizer and spraying with amino acids resulted in a noticeable and statistically significant effect. This effect was particularly evident when using a level of 500 g tree-1 of chicken waste for fertilization and a concentration of 10 mL L-1 of amino acids for spraying, as it positively impacted most parameters.