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Fluid Journal : Late Spring 2013
18 The Fluid Journal Late Spring 2013 Figure 7. Cumulative daily N2O -N emissions during the 2010 growing seasons for each N treatment: urea, urea-ammonium nitrate (UAN), ESN, ESN subsurface band (ESNssb), SuperU, UAN+Nfusion (Nf), UAN+AgrotainPlus (AP), blank, and check. Figure 6. Cumulative daily N2O-N emissions during the 2009 growing seasons for each N treatment: urea, urea-ammonium nitrate (UAN), ESN, ESN subsurface band (ESNssb), SuperU, UAN+Nfusion (Nf), UAN+AgrotainPlus (AP), blank, and check. 88th Annual Southwestern Fertilizer Conference Saturday July 20 to Wednesday July 24, 2013 San Antonio, TX most of the growing season, except for possibly some loss due to denitrification in early May 2010 when WFPS reached 80% for a short period. Growing season N losses as N2O -N were consistently <0.5% of N applied for all enhanced- efficiency N sources, including UAN, with urea having a loss of <0.8% . Expressing N2O emissions as a function of grain yield and N uptake showed greater agronomic N use efficiency for the enhanced- efficiency N fertilizers than for urea. This study shows that N source can affect N2O-N emissions following N fertilizer application. Choice of N source can be a valid management alterative for reducing N2O emissions to the environment in the semiarid western United States. Additional work is needed to verify the effectiveness of these fertilizer sources in reducing N2O emissions in other rain-fed and irrigated cropping systems, especially in humid areas with large amounts of untimely spring rainfall, which can contribute to N2O losses through denitrification. Acknowledgement: This article was extracted directly from the publication of Halvorson, A.D., S.J. Del Grosso, and C.P. Jantalia. 2011. Nitrogen Source Effects on Soil Nitrous Oxide Emissions from Strip-Till Corn. J. Environ. Qual. 40:1775-1786. Dr. Halvorson is Retired Research Soil Scientist and Dr. Del Grosso is Research Soil Scientist at the USDA- ARS in Fort Collins, CO and Dr. Jantalia is Soil Scientist at Embrapa Agrobiology, Seropedica, Rio de Janeiro. Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the USDA. USDA is an equal opportunity provider and employer.
Early Spring 2013