Submitted to: Journal of Environmental Quality
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/12/2013
Publication Date: 7/14/2014
Citation: Woodbury, B.L., Gilley, J.E., Parker, D.B., Marx, D.B., Miller, D.N., Eigenberg, R.A. 2014. Emission of volatile organic compounds after land application of cattle manure. Journal of Environmental Quality. Special Section. Livestock GraceNet. 43:1207-1218. DOI: 10.2134/JEQ2013.05.0185. Interpretive Summary: Manure from cattle can serve as a valuable fertilizer for growing crops. Odors released from manure following application to fields can be a nuisance to people downwind. This study looked at different compounds that make odors and how different application methods affect how they are released into the air. There were three compounds that accounted for most of the detectable odors that were released. In general, the largest release of most of the odor compounds was measured right after application without the addition of irrigation. The release of these compounds was greatly reduced by the addition of irrigation water. These compounds were dissolved in irrigation water, held in the soil and not released into the air. In contrast, other compounds were increased with the addition of water. These compounds are more commonly found in manure from animals that were fed a diet consisting of feed remaining after the production of ethanol. Application method should be considered when applying manure as a fertilizer to soil when people downwind will be affected by the release of odors.
Technical Abstract: Beef cattle manure can serve as a valuable source of nutrients for crop production. However, emissions of volatile organic compounds (VOCs) following land application may pose an odor nuisance to downwind populations. This study was conducted to evaluate the effects of application method, diet, soil moisture content, and time since application on VOC emissions. Manure was collected from feedlot pens where cattle were fed diets containing 0, 10 or 30% wet distillers grains (WDGS). Land application methods included surface-applying manure (i.e., no-tillage) or incorporating manure using disc tillage. The effects of soil moisture content on VOC emissions was determined by adding water to each of the plots approximately 24 hours after manure application. Isovaleric acid, butyric acid, and 4-methylphenol contributed 28.9, 18.0, and 17.7%, respectively, of the total measured odor activity values. In general, the largest emissions of volatile fatty acids (VFA) and aromatics were measured during the initial collection periods on the no-tillage plots under dry soil moisture conditions. Emissions of VFA and aromatics were reduced after water additions because these compounds were stored in the soil water matrix rather than released into the atmosphere. In contrast, sulfide emissions generally increased with the addition of the water, especially on the plots containing manure from the 30% WDGS diet. Sulfur content of manure increases with higher percentages of WDGS feed stock. Application method, diet, soil moisture content, and time since application should be considered when estimating VOC emissions.