Location: Livestock Nutrient Management ResearchTitle: Ammonia losses from a southern high plains dairy during summer Author
|Todd, Richard - Rick|
|Hagevoort, Robert - New Mexico State University|
|Casey, Kenneth - Texas A&M Agrilife|
Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 2/24/2014
Publication Date: 11/4/2014
Citation: Todd, R.W., Cole, N.A., Hagevoort, R., Casey, K.D. 2014. Ammonia losses from a southern high plains dairy during summer. ASA-CSSA-SSSA Annual Meeting Abstracts. Paper No.260-8.
Technical Abstract: Animal agriculture is a significant source of ammonia (NH3). Cattle excrete a large amount of nitrogen (N); most urinary N is converted to NH3, volatilized and lost to the atmosphere. Open lot dairies on the southern High Plains are a growing industry and face environmental challenges including reporting requirements for ammonia emissions. We sought to quantify NH3 emissions from the open lot and lagoons of a commercial New Mexico dairy during a week-long summer campaign in 2009. The 3500-cow dairy consisted of open lot, manure-surfaced corrals with total area of 22.5 ha. Milking cows were 73% of the dairy population. A feed alley flush system removed some manure to a system of four lagoons (1.8 ha). Other manure was retained on the corral surface. Open path lasers measured atmospheric NH3 concentration, sonic anemometers characterized turbulence, and inverse dispersion analysis was used to quantify emissions. Nitrogen intake was 612 and 701 g per cow daily for all cows and milking cows, respectively. Nitrogen in milk averaged 145 g per cow daily. Open lot NH3 flux densities (15-min) ranged from 8 to 221 µg per square meter per second and averaged 55 µg per square meter per second, with maxima in the afternoon and minima during early morning. Lagoon fluxes followed a similar pattern; fluxes ranged from 8 to 108 µg per square meter per second and averaged 56 µg per square meter per second. Per capita emission rate (PCER) of NH3-N averaged 252 g per cow daily from the open lot (41% of N intake) and 21 g per cow daily from the lagoons (3% of N intake). Open lot PCER were near the upper range reported for dairies in literature. However, studies were conducted during late summer when temperature-dependent NH3 emission rates would be expected to be highest. Further studies to characterize seasonal emissions are needed to augment our understanding of NH3 loss from southern High Plains dairies.