Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/15/2007
Publication Date: 1/30/2008
Citation: Powell, J.M., Misselbrook, T.H., Casler, M.D. 2008. Season and Bedding Impacts on Ammonia Emissions from Tie-stall Dairy Barns. Journal of Environmental Quality. 37:7-15. Interpretive Summary: Ammonia losses from dairy farms are thought to contribute to dust formation which can imperil human health, and to nitrogen depositions which can damage natural ecosystems. The impacts of bedding on ammonia emissions were measured from a tie-stall dairy barn in central Wisconsin during winter, summer and fall. Ammonia emissions from composted manure solids, newspaper and straw were similar and significantly greater than emissions from pine shavings. Ammonia emissions during summer and fall were similar and twice the emission rates recorded during winter. Study results can be used by producers to select beddings that minimize ammonia losses, and also by state regulators in their ammonia emission reporting requirements.
Technical Abstract: Federal and state regulations are being promulgated under the Clean Air Act to reduce hazardous air emissions from livestock operations. Whereas much is known about air emissions from livestock operations in Europe, very little data is available on emissions from livestock facilities in the USA, and the management practices that may minimize emissions. The objective of this study was to measure seasonal and bedding impacts on ammonia emissions from tie-stall dairy barns located in central Wisconsin. Four chambers each housed four dairy heifers (approx.17 mo. of age with body weights of 427 to 522 kg) for three 28d trial periods corresponding to winter, summer and fall. A 4x4 Latin Square statistical design was used to evaluate four bedding types (manure solids, chopped newspaper, pine shavings and chopped wheat straw) in each chamber for a 4-d ammonia monitoring period. Average ammonia-N emissions (g heifer-1 d-1) during summer (20.4) and fall (21.0) were similar and twice the emissions recorded during winter (10.1). Ammonia-N emissions accounted for approximately 4 to 7% of consumed feed N, 4 to 10% of excreted N, and 9 to 20% of manure ammonical N. Cooler nighttime temperatures did not result in lower ammonia emissions than daytime temperatures. Ammonia emissions (g heifer-1 d-1) from chambers that contained manure solids (20.0), newspaper (18.9) and straw (18.9) were similar and significantly greater than emissions using pine shavings (15.2). Chamber N balances, or percent difference between the inputs feed N and bedding N, and the outputs manure N, body weight N, and ammonia N were 105, 90 and 89% for the winter, summer and fall trials, respectively. Relatively high chamber N balances and favorable comparisons of study data with published values of ammonia emissions, feed N intake and manure N excretion provided confidence in the accuracy of the study results.