Project Number: 8070-11130-002-09
Start Date: Sep 28, 2012
End Date: Apr 29, 2016
Three dairies will be monitored to measure volatile organic compound (VOC) emissions from corn and alfalfa silage throughout the entire silage preservation and feeding cycle. Silage samples will be taken at different times to quantify changes in silage over time. The original crop feedstock and silage samples will be analyzed for alcohols, volatile fatty acids, and aldehydes, as well as moisture content, pH, total and volatile solids, and lactic acid. Additional variables measured will include particle size, content of readily fermentable carbohydrate, moisture content, bulk density, lactic acid bacterial population, temperature, oxygen content, silage pile configuration, exposed surface area and roughness. A mobile emissions lab containing measurement instruments will be placed adjacent to the silage pile, mixer wagon, or feedlane. Flux chambers and wind tunnels will be placed on the silage surfaces that will be monitored by instruments inside the mobile lab. Two open-path instruments will be placed to monitor undisturbed emissions emanating from the silage face, the mixer wagon, and the feedlane. Gas phase monitoring of the most abundant VOCs (e.g., small alcohols) will be done using a photo-acoustic instrument and a gas chromatograph. Additional VOCs will be determined using standard procedures approved by the U.S. Environmental Protection Agency (TO-15 and TO-11A). Monitoring data will be used to refine and evaluate the Dairy Silage Emissions Model under various environmental and management scenarios. The silage model will be incorporated in a whole farm simulation model where it will be used to evaluate the performance and economics of mitigation strategies for reducing silage emissions.