Submitted to: American Society of Agri Engineers Special Meetings and Conferences Papers
Publication Type: Other
Publication Acceptance Date: July 13, 2005
Publication Date: July 18, 2005
Citation: Woodbury, B.L., Miller, D.N., Eigenberg, R.A., Nienaber, J.A. 2005. Measuring the spatial variability of ammonia emission from feedlot surfaces as identified by electromagnetic induction methods. American Society of Agri Engineeers Special Meetings and Conferences Papers. Paper #054087. Interpretive Summary: Inexpensive equipment is needed to study odor generation. Before odors can be managed, it is necessary to understand how odors are formed. This paper describes a measurement tool that can be used in both the laboratory and the field. The equipment controls the airspace above the odor source so that samples can be easily collected. Tests showed that the equipment performed accurately. The equipment was used in the field to describe areas of gas losses.
Technical Abstract: Understanding the interactions between the environment and emission from livestock waste is essential in developing management practices designed to minimize negative environmental consequences. However, the protocol and equipment necessary to investigate these interactions at the laboratory or field-scale do not exist or are expensive. Therefore, an inexpensive dynamic flux chamber (cost: <$400 per unit) was developed to measure gaseous emissions from cattle manure in laboratory and field experiments. The hemispherical stainless steel chamber was constructed with an internal gas mixing fan. A port was attached to the chamber top, which facilitated the collection of headspace gas samples for greenhouse gases and volatile organic compounds (VOC) by solid phase microextraction (SPME). The chamber was tested to evaluate flow characteristics, and was found to perform very similarly to a continuous flow stirred reactor. Thus, concentrations measured at the sampling port were indicative of concentrations anywhere in the headspace. Preliminary results indicate a general gradation of ammonia loss from the feed bunk apron to the down-gradient end of the pen when chamber data was co-krigged with ratio electromagnetic induction (EMI) data, that was cropped to eliminate influence of metal fence. The greatest losses were measured just down-gradient from the feed bunk apron. This is most likely a result of the time the animal spends at or near the feed bunk and the amount of urine that is deposited on the bunk apron. This urine runs off and accumulates in the soil near the apron, resulting in high ammonia volatilization. Additional studies are planned to refine EMI mapping and chamber sampling techniques to minimize statistical uncertainties. However, preliminary results indicate that using EMI may be useful in better understanding ammonia emission spatial variability.