Ammonium leaching in coastal plain soils

Because of the relatively low cost of production and their high N content, the vast majority of N fertilizers used in crop production are ammonium-based. Previous research on three soils representing the range of characteristics within a field in Crisp County, Georgia documented the presence of NH4-N to 120 cm in unfertilized plots at planting and after the growing season, indicating some potential for NH4-N leaching, especially in sandy soils. Based on these findings, a series of mass balance studies were performed in an attempt to duplicate the conditions that led to NH4-N movement into lower soil profile depths. Field and undisturbed soil column studies indicated that while each of the experimental soils differed in texture, percent carbon and CEC, each had some potential to transport NH4-N past the surface soil horizons and into lower soil horizons.