Document Type : Research Paper
Authors
1
Ph.D student of Irrigation and Drainage Engineering, Faculty of Water Sciences Engineering, ShahidChamran University of Ahvaz, Ahvaz, Khuzestan, Iran
2
Associate Professor of Irrigation and Drainage Engineering, Faculty of Water Sciences Engineering, ShahidChamran University of Ahvaz, Ahvaz, Khuzestan.Iran
3
Assistant professor, Department of Soil Science, College of Agriculture, ShahidChamran University of Ahvaz
4
M.Sc of Irrigation and Drainage Engineering, Faculty of Water Sciences Engineering, ShahidChamran University of Ahvaz, Ahvaz, Khuzestan, Iran
Abstract
Nitrate is the primary source of nitrogen that is essential for the survival of plants. Therefore, nitrogenous fertilizers are used to improve plant growth. Increased use of nitrogen fertilizers causes migration of nitrate to surface and groundwater resources, resulting in their contamination. The objective of this study was to investigate the effect of potassium zeolite on nitrate and ammonium ions sorption and retention in a saturated sandy loam soil under laboratory condition. The experimental design was complete randomized blockwith four treatments consisting of potassium zeolite applications of 0, 2, 4 and 8 g zeolite per kg soil, with three replications. Ammonium nitrate fertilizer with concentration of 10g per liter was added to soil columns and then leaching was performed. Results of the study showed that with increasing the amount of potassium zeolite to soil, the leaching of nitrate and ammonium ions decreasedand their retention in soil increased. For the control treatment and use of 2, 4, and 8 g zeolite per kg soil, the amounts of nitrate exiting the bottom of the soil columns were 93.88%, 73.91%, 59.62%, and 53.61 percent of the amount of nitrate added to the soil, respectively. The respective values for ammonium were 4.74%, 4.12%, 3.37% and 3.24 percent, respectively. Based on the results obtained, application of 2, 4, and 8 g zeolite per kg soil reduced the average pore water velocity in soil to 43.79, 58.43 and 60.52 percent compared to the control treatment, respectively. Generally, increasing the amount of zeolite application to the soil decreased the hydrodynamic dispersion coefficient of nitrate ion.
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