Estimation of silage VOC emission impacts of surface-applied additives by GC-MS

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 econom...

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Main Author: K. Panke-Buisse
Format: Article
Language:English
Published: Elsevier 2023-01-01
Series:Atmospheric Environment: X
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S2590162123000060
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author K. Panke-Buisse
author_facet K. Panke-Buisse
author_sort K. Panke-Buisse
collection DOAJ
description 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 VOC emission from silage.A headspace gas chromatography (GC) method was adapted for use with a paired mass spectrometer (MS) to profile silage. 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 glycerine, olive oil, grape seed oil, and sunflower oil.Sample-to-sample variation among vials containing 5 g fresh weight (fw) silage collected from a bulked, homogenized silo sample was high, highlighting a need for sufficient replication. The most prevalent volatile acid in corn silage, acetic acid, made up the majority of observed VOCs. However, in total, eighteen VOCs were detected across all samples and the effects of treatments were assessed for each individually and for their sum as total VOC emission. Water applied to the surface of silage samples did not significantly alter VOC emissions as compared to silage alone for most VOCs. The largest observed significant effects were from the oil additives. Grape seed oil increased acetaldehyde and acetone values, while sunflower seed oil increased propionic acid and propyl acetate. Several treatments, including vegetable glycerine and seaweed extract, led to numerical decreases in VOC emissions and lower emission variability.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.
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spelling doaj.art-4b37f699c5c0432cad4f1407ce1b2dfa2023-03-14T04:08:56ZengElsevierAtmospheric Environment: X2590-16212023-01-0117100206Estimation of silage VOC emission impacts of surface-applied additives by GC-MSK. Panke-Buisse0USDA-ARS U.S. Dairy Forage Research Center, 1925 Linden Dr. Madison, WI, 53706, USAEnsiling, 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 VOC emission from silage.A headspace gas chromatography (GC) method was adapted for use with a paired mass spectrometer (MS) to profile silage. 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 glycerine, olive oil, grape seed oil, and sunflower oil.Sample-to-sample variation among vials containing 5 g fresh weight (fw) silage collected from a bulked, homogenized silo sample was high, highlighting a need for sufficient replication. The most prevalent volatile acid in corn silage, acetic acid, made up the majority of observed VOCs. However, in total, eighteen VOCs were detected across all samples and the effects of treatments were assessed for each individually and for their sum as total VOC emission. Water applied to the surface of silage samples did not significantly alter VOC emissions as compared to silage alone for most VOCs. The largest observed significant effects were from the oil additives. Grape seed oil increased acetaldehyde and acetone values, while sunflower seed oil increased propionic acid and propyl acetate. Several treatments, including vegetable glycerine and seaweed extract, led to numerical decreases in VOC emissions and lower emission variability.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.http://www.sciencedirect.com/science/article/pii/S2590162123000060SilageVOCEmissions
spellingShingle K. Panke-Buisse
Estimation of silage VOC emission impacts of surface-applied additives by GC-MS
Atmospheric Environment: X
Silage
VOC
Emissions
title Estimation of silage VOC emission impacts of surface-applied additives by GC-MS
title_full Estimation of silage VOC emission impacts of surface-applied additives by GC-MS
title_fullStr Estimation of silage VOC emission impacts of surface-applied additives by GC-MS
title_full_unstemmed Estimation of silage VOC emission impacts of surface-applied additives by GC-MS
title_short Estimation of silage VOC emission impacts of surface-applied additives by GC-MS
title_sort estimation of silage voc emission impacts of surface applied additives by gc ms
topic Silage
VOC
Emissions
url http://www.sciencedirect.com/science/article/pii/S2590162123000060
work_keys_str_mv AT kpankebuisse estimationofsilagevocemissionimpactsofsurfaceappliedadditivesbygcms