Nitrapyrin Effects On Maize N Uptake Following Pre-Plant and Side-Dress UAN.

Nitrogen fertilizer is widely applied in maize production in the USA, yet usually less than 50% of the N-applied is recovered by the crop, with the remainder being subject to the possibility of losses. The use of nitrification inhibitors to delay the transformation of NH₄ to NO₃ could potentially reduce the amount of N lost through leaching, thus keeping more of the applied N available for plant uptake. A nitrification inhibitor, a nitrapyrin (commercialized as Instinct^TM) optimized for its use with liquid fertilizers and manure, was applied with UAN fertilizer (28% N). The objectives were to assess if the use of Instinct^TM (i) positively impacts maize N uptake (ii) is associated with higher maize yields. To accomplish these objectives a field experiment including three N rates (0, 90 and 180 kg hectare^-1), two timings (pre-plant and side-dress) and with or without Instinct^TM, was conducted on a dark prairie soil at Purdue University Agronomy Center for Research and Education (ACRE) (40°28'07'' N, 87°00'25'' W) near West Lafayette, Indiana. The use of Instinct^TM was associated with a higher N-uptake at maize physiological maturity when 180 kg of N hectare^-1 were applied, being this effect statistically significant. Mean yields were significantly higher (LSD 5%) when Instinct^TM was used in conjunction with UAN at a rate of 90 kg of N.hectare^-1  pre-plant applied. The use of Instinct^TM in conjunction with UAN showed potential to increase N-uptake and maize yields, though further experimentation would be needed for a robust recommendation of this management practice.