The role of organic fertilization by different application methods and spraying with proline acid in improving the growth characteristics of neglected pomegranate trees

Abstract

 The experiment was conducted in the fields belonged to Department of Horticulture and Landscape, College of Agriculture, Tikrit University, during the 2022 growing season, on Salimi pomegranate trees, three years old, suffering from neglect and lack of care, in order to improve their growth. The experiment included two factors: the first was the addition of organic fertilizer (sheep manure) at three levels (0, 3, and 6 kg tree^-1) by different methods, and the second factor was spraying with proline acid at three concentrations (0, 50, and 100 mg L^-1). The experiment was carried out according to a randomized complete block design (RCBD) with three replications. The data were analyzed statistically and the means were compared using Duncan's multiple range test at a probability level of 0.05. The results showed that the treatment of adding 6 kg of sheep manure per tree in a circular trench around the tree resulted in an increase in the total leaf area, the percentage increase in tree height and stem diameter, the length and diameter of annual shoots, and the percentage of dry matter in the leaves. The addition of the same amount in three pits around the stem of the tree achieved a significant increase in the area of a single leaf. Spraying with proline acid at a concentration of 100 mg L^-1 also caused a significant increase in the above-mentioned traits, as well as the area of a single leaf. The interaction treatment between the addition of organic fertilizer at a rate of 6 kg tree^-1 in a circular trench around the tree and the spraying with proline acid at a concentration of 100 mg L^-1 gave the highest values for the studied vegetative growth traits and superiority on the control treatment.