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^: *http://elibrary.asabe.org/toc.asp (http://elibrary.asabe.org/toc.asp)
^: Parker D.B.; Waldrip H.M.; Casey K.D.; Woodbury B.L.; Spiehs M.J.; Webb K.; Willis W.M.
^: How do temperature and rainfall affect nitrous oxide emissions from open-lot beef cattle feedyard pens? [ . ()]
^: Transactions of the ASABE / Amer. soc. of agriculture and biol. engineering. - St. Joseph (Mich.), 2018; Vol.61,N 3. - P. 1049-1061
^: 2018
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^: Temperature is a primary factor affecting greenhouse gas (GHG) emissions from agricultural soils, but little is known about how temperature affects nitrous oxide (N2O) emissions from manure. The majority of grain-fed cattle in the Texas Panhandle are finished in large, earthen-surfaced, open-lot feedyards. Manure accumulates in feedyard pens and creates an environment high in nitrogen (N) and carbon (C) that can lead to N2O losses. In previous studies, N2O-N emissions from feedyard manure have been highly variable, ranging from negligible amounts from dry manure to 200 mg m-2 h-1 after a simulated rainfall event. The objective of this research was to determine how temperature affects N2O emissions from feedyard manure following rainfall. A recirculating flow-through, non-steady-state (RFT-NSS) chamber system with 1 m2 pans was used to monitor N2O emissions from beef cattle manure following a single 25.4 mm simulated rainfall event. Emissions were monitored at manure temperatures of 5.0C, 11.2C, 17.2C, 21.5C, 26.8C, 31.0C, 38.1C, and 46.2C. At all temperatures, a single N2O episode was observed following rainfall, peaking 2 to 11 h after rainfall with duration of 2 to 3 d. A second N2O episode was observed at temperatures ≥31.0C, peaking 3 to 4 d after rainfall with duration of 18 d. When present, the second N2O episode accounted for 72% to 83% of the 20 d cumulative emissions. A step-increase in cumulative N2O emissions was observed between 26.8C and 31.0C, believed to be due to a major shift from denitrification to nitrification as the primary process of N2O production. Empirical regression models were developed for predicting cumulative N2O emissions based on temperature, which showed 88% agreement between predicted and field-observed N2O-N flux rates. These regression models will be useful for further quantification of N2O emissions from open-lot beef cattle feedyards in the U.S. Southern High Plains and for assessment of practices for reducing GHG emissions. aref1

^TRN: 1837550
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