|CASEY, KENNETH - Texas A&M Agrilife|
Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/27/2014
Publication Date: 11/3/2014
Citation: Casey, K.D., Waldrip, H., Todd, R.W., Cole, N.A. 2014. Greenhouse gas emissions from beef cattle feedlot pen surfaces in Texas. ASA-CSSA-SSSA Annual Meeting Abstracts. Paper No.96-1.
Technical Abstract: Accurate estimation of greenhouse gas (GHG) emissions, including nitrous oxide and methane from open-lot beef cattle feedlots is an increasing concern given the current and potential future reporting requirements for GHG emissions. Research concerning nitrous oxide and methane fluxes from the manure management system at feedlots, however, has been very limited. This study was conducted to quantify nitrous oxide and methane flux rates from pen surfaces at two commercial beef cattle feedlots in the Texas Panhandle during 2013. Fluxes from pen surfaces were measured using 219 mm i.d., non-flow-through non-steady-state (NFT-NSS) chambers on 25 sampling days at 12:00 pm (Central Standard Time) during spring and fall, in five, 5-d measurement campaigns. Ten chambers were arranged in two rows of five, strategically covering representative areas of the pen, including areas near feedbunks and water troughs. Headspace samples were collected from the chambers at 0, 10, 20 and 30 min using 20 ml polypropylene syringes, transferred to evacuated 12 mL Exetainer vials, and analyzed using a gas chromatograph. From the nitrous oxide and methane concentrations, flux densities were calculated using the Quad method. Nitrous oxide fluxes varied considerably across the pen surface, generally being higher on manure mounds and at the toe slope of manure mounds. Median nitrous oxide-nitrogen fluxes for each 5-d campaign were 0.01, 0.01, 1.38, 1.14 and 0.17 mg m-2 h-1, respectively. Methane fluxes were generally low under the dry conditions experienced during the study but were considerably higher from moist areas and somewhat higher over manure mounds. Median methane fluxes for each 5-d campaign were 0.01, 0.44, 0.14, 0.01, and 0.22 mg m-2 h-1, respectively. Further ongoing work is investigating flux rates in other seasons and identifying contributing factors.