Nitrogen Source Effects On Nitrous Oxide Emissions From a Strip-Tilled Corn Field.

The effects of N source on nitrous oxide (N₂O) emissions from a strip-till, irrigated continuous corn field was evaluated near Fort Collins, CO.  Six N fertilizer sources (urea, ESN, SuperU, UAN, UAN+AgrotainPlus, UAN+Nfusion) were surface band applied at 202 kg N/ha near the corn row at corn emergence, including a subsurface band application of ESN, and watered (19 mm irrigation water) into the soil the next day.  A check plot, located in a separate plot, and a blank treatment (no N applied) were also included.  Nitrous oxide fluxes were measured during the growing season using static, vented chambers for gas sample collection, one to three times per week, and analyzed with a gas chromatograph.  All N sources had significantly lower growing season N₂O emissions than dry granular urea in 2009.  Cumulative increases in daily N₂O fluxes were more rapid for urea and UAN than the other N sources following N fertilizer application.  The enhanced efficiency fertilizers (polymer-coated, stabilized, and slow release) sources reduced N₂O emissions in a strip-tilled, irrigated corn system during the 2009 growing season.  Corn grain yields in 2009 were not significantly different between N sources, but greater than with no N applied.  Results from 2010 will be included.