IRRIGATION WATER QUALITY AND ANTIOXIDANTS EFFECTS ON THE CHEMICAL COMPOSITION OF SWEET ORANGE

Abstract

The existent research aimed to study the effects of irrigation with liquefied water, saline-well water, and foliar application of aspartic and ascorbic acids on the chemical properties of grafted orange seedlings in the years 2020–2021 at the Horticulture and Forestry Division, Najaf Agriculture Directorate, Iraq. The main plot was the irrigation water (liquefied and saline-well water). Meanwhile, foliar application of aspartic acid (0, 100, and 150 mg.L-1) and ascorbic acid (0, 4000 mg.L-1) served as the second and third factors in subplots. Compared with the saline-well water, regular liquefied water had a significant positive impact on the improvement of chemical traits, i.e., the liquefied water attained the highest rate of nitrogen content in leaves (2.600%) compared with the saline-well water (2.239%). Ascorbic acid (4000 mg.L-1) also had a significant effect on the leaf’s contents, providing the highest percentage of phosphorus (0.4060%) and reduced sodium (0.5277%) compared with the control in the leaves of orange seedlings. The saline-well water with no addition of ascorbic acid (control) provided the highest average content of the amino acid proline (132.2 μg.g-1 fresh weight) in the sweet orange leaves compared with the other treatments and their interactions. Sweet orange seedlings with foliar application of aspartic and ascorbic acids authenticated that the peroxidase activity rate appeared more effective than all other treatments and the control.