|Powell, J mark|
Submitted to: Transactions of the ASABE
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/15/2007
Publication Date: 6/15/2007
Citation: Powell, J.M., Misselbrook, T.H., Holmes, B.J. 2007. Design and Calibration of Chambers for Measuring Ammonia Emissions from Tie-stall Dairy Barns. Transactions of the ASABE. 50(3):1045-1051. Interpretive Summary: Dairy barns are thought to emit large amounts of ammonia, which can have detrimental effects on human health and natural ecosystems. In the U.S., relatively little is known about ammonia emissions from dairy barns. A conventional tie-stall dairy barn was remodeled into four chambers to evaluate ammonia emissions from dairy cows fed different diets, from different beddings, etc. This paper describes technical aspects of chamber design, operation and calibration. Calibration results indicated that the chambers should provide precise data on ammonia emissions, data which can be used to develop ammonia emission factors for tie-stall dairy barns in the Midwest USA.
Technical Abstract: Dairy barns are thought to emit large amounts of ammonia, which can have detrimental effects on human health and natural ecosystems. In the U.S., relatively little is known about the processes that affect the rate and magnitude of ammonia emissions from dairy barns. The end of a conventional tie-stall dairy barn was remodeled into four chambers (four animals per chamber) to initially evaluate dairy diet and bedding impacts on ammonia production and loss. This paper describes technical aspects of chamber design, operation and calibration. Chamber walls consisted of drop-down curtains of polyvinyl material with Velcro seals at edges and weighted at the bottom to minimize air loss other than through the exhaust ducts. Curtains were attached to automatic roll-up, roll-down mechanisms fixed to the ceiling. Intake air, which was drawn from outside the barn, provided information on background ammonia levels. Two types of chamber calibrations were performed (1) the release and capture of known amounts of ammonia gas, and (2) total nitrogen (N) balances for growing heifers, or the percent difference between N outputs (manure, livestock mass, and ammonia) and N inputs (feed and bedding). From 88 to 131% of released ammonia was captured using the ammonia release-capture calibration method, and 93 to 104% of output N was accounted for by input N. Calibration results indicate the chambers should provide precise data on ammonia emitted from tie-stall dairy barns under the prevailing management and environmental conditions.