Poster Number 543
Tuesday, 7 October 2008
George R. Brown Convention Center, Exhibit Hall E
The effect of several N sources on nitrous oxide (N<sub>2</sub>O) emissions from an irrigated, no-till (NT) continuous corn field was investigated. Emissions were monitored in plots receiving 246 kg N/ha during the 2007 growing season and 202 kg N/ha during the 2008 growing season. Nitrogen sources included dry granular urea, liquid urea-ammonium nitrate (UAN), two polymer-coated urea (
PCU) sources, and urea and UAN treated with nitrification and urease inhibitors. The N was surface band applied in the corn row at emergence with 1.3 cm of irrigation water applied within 3 days of N application. Plot size was 2.7 x 4.6 m for each N source, with 3 replications in a randomized complete block design. N<sub>2</sub>O fluxes were measured during the growing season at two locations within each plot using static, vented chambers, one to three times per week, and a gas chromatograph analyzer. In 2007, N<sub>2</sub>O emissions were not significantly different between urea and UAN. The PCU fertilizers and urea and UAN fertilizers treated with nitrification and urease inhibitors showed significantly lower N<sub>2</sub>O emissions than dry granular urea in 2007. Only the urea and UAN sources treated with the nitrification inhibitors had significantly lower N<sub>2</sub>O emissions than UAN in 2007. Based on the 2007 results, these N sources need further evaluation to determine their effectiveness in reducing N<sub>2</sub>O emissions in irrigated cropping systems. The study was continued in 2008.
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