Nitrapyrin Impacts On Nitrous Oxide Emissions with Alternate UAN Rates In Indiana Maize Production.

Agricultural soil management has been signaled by EPA as the largest source of N₂O emissions in the US. The use of nitrification inhibitors is one of several management practices that show potential to reduce the amount of N₂O released from agricultural fields. Since 2010, a reformulation of nitrapyrin optimized to be used with liquid fertilizers and manure (Instinct^TM) has been made available to farmers in the US. Our objectives are to assess if Instinct^TM can both delay and reduce N₂O emissions in the growing season time period after UAN application in a highly productive maize system. The field experiment comprised three N rates (0, 90 and 180 kg hectare^-1), two timings (pre-plant and side-dress) and with or without Instinct^TM , and it 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. Nitrous oxide fluxes were measured with vented flux chambers at weekly or biweekly intervals. N2O emissions were highly variable within treatments. Nevertheless, the following trends were observed: higher N rates were associated with overall higher N₂O emissions; the use of Instinct^TM proved to be effective in the reduction of mean N₂O emissions.