Seepage from deep bedded and poultry litter systems

The work reported indicates that there could be a potential of ground water pollution by NO₃-N from turkey facilities built on both sandy and clay soils. At four different depths (30.54, 61.08, 91.62, and 122.16 cm), the NO₃-N levels for the clay soil were 1572, 497, 66, and 28 ppm, and those for the sandy soil were 293, 425, 324, and 164 ppm, respectively. No significant P increases were observed but there did exist a significant increase of K in the topsoil for both clay and sandy turkey structures. The results show that swine hoop houses with less than three or four years of age may not pose a threat to groundwater pollution due to the leaching of nutrients. The only dairy feedlot sampled in this study, although it has been used for more than 20 years, did not show leaching of NO₃-N and P. However, it did show a significantly elevated concentration of potassium in the topsoil, as compared to the background sample. More sites should be investigated to verify this.