Effect of Spring Application of N Fertilizer and a Nitrification Inhibitor on Corn Grain Yields
Nitrogen (N) fertilizer management for corn production continues to be a very important issue in Iowa. The goal of N management is to apply enough fertilizer to maximize profits for the crop producer and to limit the potential for environmental contamination from unused fertilizer. The ammonium (NH4) form of N fertilizer doesn’t leach or denitrify in soils. Eventually NH4 is converted to nitrate (NO3) in soils, and once this occurs the potential for N loss increases. Nitrification inhibitors (NI) maintain, for a time, ammonium (NH4) in soils thus reducing the risk of N loss. Research on NIs in Iowa has not shown predictable corn yield increases due to their use, especially when applied in the spring in liquid N fertilizers. This may be because NIs are volatile and may be lost from the soil during application. The purpose of this study was to evaluate a reformulation of the NI nitrapyrin. This product is currently being sold as Stay N. The reformulated product is less volatile than the old material.