Location: Cell Wall Biology and Utilization Research
Title: Estimation of silage VOC emission impacts of surface-applied additives by GC-MSAuthor
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Submitted to: Atmospheric Environment
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 2/12/2023 Publication Date: 2/16/2023 Citation: Panke-Buisse, K. 2023. Estimation of silage VOC emission impacts of surface-applied additives by GC-MS. Atmospheric Environment: X.17.Article 100206. https://doi.org/10.1016/j.aeaoa.2023.100206. DOI: https://doi.org/10.1016/j.aeaoa.2023.100206 Interpretive Summary: Ensiling, the process of microbial acidification and preservation of wet forage for livestock feed that yields silage, produces a significant amount of volatile organic compounds (VOCs). Measurement of the chemical species involved, their emission to the atmosphere, environmental impacts, and economic losses to agricultural producers have been discussed in previous studies. Strategies for mitigation of silage VOC emission are limited and focus primarily on ensiling efficiency and silage additives at time of ensiling. However, one novel strategy employed by some producers to reduce airborne particulates, “wetting down” or applying water to rations at the feed bunk may also impact VOCs emission. We tested this method in parallel with several other chemical solutions with potential nutritional relevance for effects on VOCs emission from silage. Technical Abstract: A headspace gas chromatography (GC) method was adapted for use with a paired mass spectrometer (MS) to profile silage volatile organic compounds (VOCs). The effects on corn silage VOC emissions of surface-applied solutions across a range of pH, viscosity, and hydrophobicity were determined by GC-MS VOC headspace measurements. Surface-applied liquid additives included: water, citric acid, malic acid, molasses, sorghum syrup, yucca extract, seaweed extract, vegetable glycerin, olive oil, grape seed oil, and sunflower oil. Most additives showed no significant effects on silage VOC emission. Numerically, oil additives tended to increase VOC emissions from silage. Sunflower seed oil significantly increased propionic acid and propyl acetate emissions. Grape seed oil significantly increased acetaldehyde and acetone emissions. These data suggest that oils applied to the surface of silage may increase VOC emissions. More work is needed to understand interactions between silage VOC emissions and surface-applied mitigation strategies, including: constraining silage sample heterogeneity; investigation of the prevalence of oil-based feed additives and potential impacts on whole-farm VOC emissions; and in situ, on-farm measurements of VOC emission from treated piles. |
