394-23 Atmospheric Emissions of N2O, CH4, and CO2 From Different Nitrogen Fertilizers.



Wednesday, October 19, 2011
Henry Gonzalez Convention Center, Hall C, Street Level

Karamat Sistani, Marcia Jn-Baptiste, Nanh Lovanh and Kimberly Cook, USDA-ARS AWMRU, Bowling Green, KY
There is a growing interest in quantification of significant sources of greenhouse gas (GHG) emissions from agricultural practices. Efficient N fertilizers and alternative sources of N that produce low GHG emissions from soil are needed to reduce the impact of agricultural practices on global warming. We quantified and compared growing season fluxes of N2O, CH4, and CO2 resulting from application of different chemical N fertilizers, poultry litter, and commercially available enhanced-efficiency N fertilizers as follow: polymer-coated urea (ESN®), superU®, urea-ammonium  nitrate (UAN), UAN + AgrotainPlus® (urease inhibitor), ammonium nitrate (NH4NO3), poultry litter, and poultry litter + AgrotainPlus  in a no-till corn (Zea mays L.) production system.  Greenhouse gas fluxes were measured during two growing seasons using static, vented chambers. The enhanced-efficiency N fertilizer ESN delayed the N2O flux peak by 3 to 4 weeks compared to other N sources. No significant differences were observed between enhanced-efficiency N fertilizers and other N fertilizer sources such as UAN, urea, and NH4NO3. Cumulative growing season N2O emission from poultry litter was significantly greater than other N sources. In general, the N2O loss (2-y average) as a percentage of N applied as fertilizer was 0.69 for Super U, 0.98% for UAN, 2.0% for ESN, 0.8% for urea, 1.7% for NH4NO3, and 4.5% for poultry litter.

The CH4-C and CO2-C emissions were highly impacted by the environmental factors than the N sources. No particular trend was observed among N sources with regard to CH4-C and CO2-C emissions for the two growing seasons of this study. The cumulative growing season CO2 fluxes were less variable than CH4, however, no significant differences or trends were observed among N sources.   

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