Sidedress Nitrogen Rates and Costs for Southeastern Cotton Production

Nitrogen (N) is typically the most important fertilizer input for cotton, therefore, careful consideration of rates including costs are required to optimize productivity and profits.  These decisions can be complicated by tillage systems that include cover crops and/or residual effects from organic N sources.  This experiment was conducted at the Wiregrass Research and Extension Center in Headland, AL on a Fuquay sand (loamy, kaolinitic, thermic Arenic Plinthic Kandiudults) during crop years 2006-2008.  A traditional cotton response trial was embedded in a trial that examined time of application (fall vs spring), N source (commercial fertilizer, and poultry litter), and N rate (0 30, 60, and 90 lb N ac^-1 as commercial fertilizer and 0, 1, 2, and 3 tons ac^-1 as poultry litter on an as-sampled basis) for a cover crop.  All corresponding eight row cotton plots were split with four rows receiving 90 lb N ac^-1 at sidedress, while the other four rows were not fertilized.  These studies conducted simultaneously enable a comparison across multiple factors that affect optimal N rates and subsequent costs.