ARS | Publication request: Evaluating the Spatial and Temporal Variability of Ammonia Emissions from Feedlot Surfaces Using Electromagnetic Induction

Submitted to: Meeting Abstract
Publication Type: Abstract
Publication Acceptance Date: November 9, 2005
Publication Date: November 9, 2005
Citation: Woodbury, B.L., Eigenberg, R.A., Nienaber, J.A. 2005. Evaluating the spatial and temporal variability of ammonia emissions from feedlot surfaces using electromagnetic induction. Meeting Abstract. 2005 International Annual Meetings American Society of Agronomy, Crop Science Society of America, Soil Science Society of America, 119, #5.

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: <$00 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. This 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 using multiple point chamber data with EMI may be useful for better understanding ammonia emission spatial variability.