Location: Soil, Water & Air Resources ResearchTitle: Laboratory evaluation of surface amendments for controlling greenhouse gas emissions from beef cattle feedlots. Author
Submitted to: International Journal of Energy and Environmental Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/1/2013
Publication Date: 11/27/2013
Citation: Aguilar, O., Maghirang, R., Trabue, S.L., Rice, C., Erickson, L. 2013. Laboratory evaluation of surface amendments for controlling greenhouse gas emissions from beef cattle feedlots.. International Journal of Energy and Environmental Engineering. 4:1-14. Interpretive Summary: Cattle feedlot surfaces are sources for greenhouse gas (GHG) emissions. A laboratory study was conducted to determine if greenhouse gas emissions could be reduced by surface amendments. Surface amendments included: organic residues (i.e., sorghum straw, prairie grass, woodchip); biochar, and 3) activated carbon. All amendment materials showed significant reduction of nitrous oxide (N2O) and carbon dioxide (CO2) emissions compared to the control (i.e., no amendment). None of the amendments were effective when feedlot surfaces were moist early on, but after 10-15 days surfaces treated with biochar significantly reduced both nitrous oxide and methane emissions. No significant difference was observed in GHG emissions when the amendments were placed on top or mixed within the top surface layer of the manure. This study shows that mangement practice can impact levels of greenhouse gases. Information in this report will be of value for growers, engineers, and regulatory officials on the impact cattle feedlots have in local communities.
Technical Abstract: Pen surface amendments for mitigating emissions of greenhouse gases (GHGs), such as nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2), from beef cattle feedlots, were evaluated under controlled laboratory conditions. Amendments were organic residues (i.e., sorghum straw, prairie grass, woodchip), biochar from those organic residues and from beef cattle manure, and activated carbon. Manure samples were collected from several randomly selected pens from two beef cattle feedlots in Kansas and used in the experiments, either as dry (0.10 g • g-1 wet basis water content) or moist (0.35 g • g-1 wet basis). For each amendment, four different treatment levels (i.e., amounts of material) were placed on top of manure samples in glass containers and analyzed for GHG emissions using a photo-acoustic infrared multi-gas analyzer. From measured concentrations, emission rates were determined. For the dry manure conditions, all amendment materials showed significant reduction of N2O and CO2 emissions compared to the control (i.e., no amendment). For the moist manure conditions, none of the amendments showed significant effects on GHG emissions during the first 8 days; at days 10 and 15 after application, however, the biochar materials performed significantly better than the control (i.e., no surface amendment) in reducing N2O and CH4 emissions. No significant difference was observed in GHG emissions when the amendments were placed on top or mixed within the top surface layer of the manure.