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Submitted to: Professional Animal Scientist
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 8/31/2009 Publication Date: 12/1/2009 Citation: Leytem, A.B., Dungan, R.S., Bjorneberg, D.L. 2009. Case study: Seasonal and Spatial Distribution of Ambient Ammonia Concentrations Measured at a Large Open-Lot Dairy. The Professional Animal Scientist. 25:786-793. Interpretive Summary: The volatilization of ammonia from dairy production facilities is not only a loss of valuable nitrogen, but also an air quality concern because ammonia plays a role in the formation of airborne particulate matter, which can be a health hazard. The ambient ammonia concentrations over several seasons at three locations (open lots, compost yard, lagoon) throughout a large open-lot dairy were determined as well as the spatial distribution of ammonia over the open-lot area. There was a significant effect of location which followed the trend lot > lagoon = compost > background with averages of 0.58, 0.33, 0.30, and 0.04 mg ammonia/m3, respectively. The effect of weather and lot conditions on the spatial distribution of ammonia across the lots was evident with lower concentrations and less spatial variability in winter months when the lots were frozen compared to wetter warmer months. Lower ammonia concentrations and less spatial variability were also measured when manure stockpiles were removed from the open-lots and the lots were dry. There were significantly greater ammonia concentrations generated in the lot area versus the compost and lagoon areas which were not significantly different. As the lots are greater in size by a factor of ~6, it is evident that ammonia emissions from this sector of the dairy contribute the greatest amount of ammonia to the atmosphere. Technical Abstract: The volatilization of ammonia (NH3) from dairy production facilities is not only a loss of valuable N, but also an air quality concern because NH3 plays a role in the formation of airborne particulate matter, which can be a health hazard. The ambient NH3 concentrations over several seasons at three locations (open lots, compost yard, lagoon) throughout a large open-lot dairy were determined as well as the spatial distribution of NH3 over the open-lot area. There was a significant main effect of location (P < 0.0001) which followed the trend lot > lagoon = compost > background with averages of 0.58, 0.33, 0.30, and 0.04 mg NH3/m3, respectively. The effect of weather and lot conditions on the spatial distribution of NH3 across the lots was evident with lower concentrations and less spatial variability in winter months when the lots were frozen compared to wetter warmer months. Lower NH3 concentrations and less spatial variability were also measured when manure stockpiles were removed from the open-lots and the lots were dry. There were significantly greater NH3 concentrations generated in the lot area versus the compost and lagoon areas which were not significantly different. As the lots are greater in size by a factor of ~6, it is evident that NH3 emissions from this sector of the dairy contribute the greatest amount of NH3 to the atmosphere. |
