Abstract
In this study, a discrepancy was found in the patterns of ammonium leaching between the studied locations and between the horizons of the soils of the studied sites. The sites of Beit Aana, Al-Qutailbiya, Quorfase and Al-Waha Spring were characterized by high levels of leaching, whereas the highest concentrations of ammonium leaching were measured in December 2020 and March 2021, ranged between 5.74 and 5.81 mg/l. However, the lowest concentration 0.97 mg/l was recorded in February 2021 in the sites of Bestwair, Beit Al-Alouni, Geiboul and Al-Rahbeyia with lower levels of leaching. The highest concentrations of nitrate leaching were obtained during November 2020 and April 2021, ranged between 3.51 and 4.31 mg/l, while the lowest concentration of nitrate 0.59 mg/l was determined in January 2021. It was found that the levels of ammonium leaching decreased with depth, largely due to the adsorption of ammonium on the organic matter (OM) and clay minerals. The statistical study showed a correlation between ammonium leaching and the following variables: OM, saturated hydraulic conductivity (SHC) and pH. Regression equations representing ammonium leaching in soil horizons and their role were also obtained.