Soil amendments, Clinoptilolite, Soil column, Nitrate leaching, Particle size

Due to low efficiency of fertilizer use, nitrogen fertilizers result in environmental problems. Therefore, use of soil amendments such as zeolite becomes important. The aims of this study were to investigate the influence of size (mm and μm) and usage (20 and 60 grams per kilogram of soil) of natural zeolite of clinoptilolite (Cp) and surfactant-modified zeolite (SMZ) on soil nitrate and ammonium leaching and on wheat plant performance using soil columns and applying wastewater for irrigation at Greenhouse of Isfahan University of Technology in 2015-2016. The experiment was factorial with completely randomized design with three replications for each treatment. The results showed that these amendments simultaneously improved wheat plant growth and increased the amount of nitrogen uptake by plants. So that, the concentration of nitrogen of the grain and nitrogen harvested by the plant in Cp receptor columns were significantly (1.45 and 2.49%) higher than SMZ receptor columns. Also, with the increasing level of modifier usage, the amount of nitrate-nitrogen in the output decreased significantly (at 5% level). Still, the type of modifier had no significant effect on the amount of leached nitrogen.