Pronitridine Nitrification Inhibitor With Urea Ammonium Nitrate for Corn

Nitrification inhibitors have been used to enhance the efficiency of nitrogen fertilizers. This research evaluated the effectiveness of nontreated urea ammonium nitrate (UAN) at 0, 67, 135, 202, and 270 kg N ha-1 as well as UAN treated with nitrification inhibitors (pronitridine at 9.4 and 18.8 L ha-1 or nitrapyrin at 0.5 kg a.i. ha-1) to enhance N uptake and increase yield of corn (Zea mays L.). The study took place from 2012-2014 in upstate Missouri on a claypan soil. During the experiments, environmental conditions (high, medium, and low yielding years) affected corn response to pronitridine and nitrapyrin. In general, UAN plus pronitridine at 9.4 L ha-1 had similar effects on corn compared pronitridine at a higher (18.7 L ha-1) rate. During a high-yielding year (2014), in order to produce yields equivalent to 67 kg N ha-1 plus pronitridine at 9.4 L ha-1 or nitrapyrin, UAN needed to be increased 14 to 19%. Similarly, the amount of nontreated UAN needed to be increased 8 to 11% for yields to be equivalent to UAN at 135 kg N ha-1 plus pronitridine at 9.4 L ha-1 or nitrapyrin. Grain N removal and agronomic efficiency was highest with pronitridine at 9.4 L ha-1 and nitrapyrin combined with 67 and 135 kg N ha-1, respectively. This research indicates that pronitridine was as effective as nitrapyrin when added to a pre-emergence application of UAN placed between the rows in a dribble band.