Effects of Livestock Antibiotics on Nitrification and Denitrification in Soils Along a Topographic Gradient.

Several types of antibiotics are widely included in poultry feed to improve animal growth yields. Most of the antibiotics are excreted in manure and applied to soils.  One concern with this practice is that microbially-mediated nutrient cycling in soils could be affected, which could influence crop productivity and water quality. The main objectives of this study are to determine the effects of increasing levels of livestock antibiotics on nitrification and denitrification rates in soils along a topographic gradient that contain different hydrological and chemical characteristics.