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Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 3/13/2010 Publication Date: 9/1/2011 Citation: Leytem, A.B., Dungan, R.S., Bjorneberg, D.L., Koehn, A.C. 2011. Emissions of Ammonia, Methane, Carbon Dioxide and Nitrous Oxide From Dairy Cattle Housing and Manure Management Systems. Journal of Environmental Quality. 40(5):1383-1394. Interpretive Summary: Concentrated animal feeding operations (CAFOs) emit trace gases such as ammonia, methane, carbon dioxide, and nitrous oxide to the atmosphere. While ammonia is a precursor to fine particulate matter that can affect livestock and human health and air quality, methane, carbon dioxide, and nitrous oxide are potent greenhouse gases. The implementation of air quality regulations in livestock-producing states increases the need for accurate on-farm determination of emission rates that reflect the range of animal production facilities and climatic conditions that exist in the U.S. Therefore, the objective of this study was to determine the emission rates of ammonia, methane, carbon dioxide, and nitrous oxide over the course of one year from three source areas (open-lots, lagoon, compost) on a large open-lot dairy located in southern Idaho to determine both diurnal and seasonal trends in emissions. There were strong diurnal trends in the emission of all trace gases at all locations studied. Gas concentrations tend to be lower in the late evening and early morning and then increase throughout the day as temperature, wind speed, and animal activity increase. There was some seasonal variation in ammonia and methane. Ammonia emissions from the lots tend to be greatest in early spring when the lots are wet and temperatures are warming, then as the lots dry during the summer, emissions tend to be lower. In winter when the lots are frozen over, there is also a decrease in ammonia emissions. There did not seem to be much of a seasonal effect for the emissions of methane, carbon dioxide, or nitrous oxide from the lots. The emission of ammonia, carbon dioxide, and nitrous oxide from the lagoons did not seem to fluctuate seasonally, although methane emissions dramatically increased as temperatures warmed up in the later summer and early fall. Emissions from the compost area were affected by compost management. Ammonia, methane, and carbon dioxide emissions tended to increase during periods when the compost was being turned and new compost was brought into the composting area, while there was little change in nitrous oxide emissions from the compost area over time. Average emissions per cow per day from the open-lots were 0.12 kg ammonia, 0.49 kg methane, 26.9 kg carbon dioxide, and 0.01 kg nitrous oxide. Average emissions from the lagoon (g/m squared/d) were 1.5 g ammonia, 132 g methane, 391 g carbon dioxide, and 0.36 g nitrous oxide. Average emissions from the compost facility (g/m squared/d) were 1.7 g ammonia, 14.8 g methane, 547 g, and 0.93 g nitrous oxide. The combined emissions of ammonia, methane, carbon dioxide, and nitrous oxide from the lots, lagoon and compost averaged 0.13, 1.5, 33.4, and 0.02 kg per cow per day, respectively. The open lot areas had the greatest contribution to emissions of ammonia, carbon dioxide, and nitrous oxide with averages of 76, 75, and 53% of total farm emissions. The methane emissions were greatest from the lots in the spring (71% of total), but once temperatures increased, the lagoon became the largest source of emissions averaging 64% of total methane emissions for the remainder of the year. Data from this study can be used to develop trace gas emissions factors from open-lot dairies in southern Idaho and potentially other open-lot production systems in similar climatic regions. Technical Abstract: Concentrated animal feeding operations emit trace gases such as ammonia (NH3), methane (CH4), carbon dioxide (CO2), and nitrous oxide (N2O) to the atmosphere. The implementation of air quality regulations in livestock-producing states increases the need for accurate on-farm determination of emission rates. The objective of this study was to determine the emission rates of NH3, CH4, CO2, and N2O from three source areas (open-lots, lagoon, compost) on a commercial dairy located in southern Idaho. Average emissions per cow per day from the open-lots were 0.12 kg NH3, 0.49 kg CH4, 26.9 kg CO2, and 0.01 kg N2O. Average emissions from the lagoon (g per m square per day) were 1.5 g NH3, 132 g CH4, 391 g CO2, and 0.36 g N2O. Average emissions from the compost facility (g per m square per day) were 1.7 g NH3, 14.8 g CH4, 547 g, and 0.93 g N2O. The combined emissions of NH3, CH4, CO2, and N2O from the lots, lagoon and compost averaged 0.13, 1.5, 33.4, and 0.02 kg per cow per day, respectively. The open lot areas generated the greatest emissions of NH3, CO2, and N2O contributing 76, 75, and 53% to total farm emissions. Methane emissions were greatest from the lots in the spring (71% of total) after which the lagoon became the largest source of emissions (64% of total) for the remainder of the year. Data from this study can be used to develop trace gas emissions factors from open-lot dairies in southern Idaho and potentially other open-lot production systems in similar climatic regions. |
