TRANSPORT OF NITROGEN FORMS IN A SANDY ENTISOL WITH COAL COMBUSTION BY-PRODUCT GYPSUM AMENDMENT

The effect of flue-gas desulfurization gypsum (FGDG) on soil physical and chemical characteristics which influence leaching of nitrate (NO,) was investigated. Effects of FGDG amendment at 0, 4.5 and 9.0 Mg ha(- 1) on transport of nitrate (NO3-), ammonium (NH4+), and bromide (Br-) in a Candler fine sand were investigated in a leaching column experime nt, with N application equivalent to 180 kg N ha(-1), as either calciu m nitrate (CN) or ammonium nitrate (AN). The columns were leached with 2860 mt of water, equivalent to 65 cm rainfall. Cumulative amount of NO3-N in 2860 mL leachate accounted for 61 and 72% of the total NO3-N applied as CN and AN, respectively. Application of gypsum at 4.5 Mg ha (-1) decreased the leaching of NO, from AN by 22% as compared to that without the application of gypsum. Total-N recovery with or without FG DG accounted for 62 to 67% and 69 to 78% of total N applied as CN and AN, respectively.