Greenhouse gas formation during the ensiling process of grass and lucerne silage. (15th February 2022)

• Record Type: Journal Article
• Authors: Schmithausen, Alexander J.; Deeken, Hauke F.; Gerlach, Katrin; Trimborn, Manfred; Weiß, Kirsten; Büscher, Wolfgang; Maack, Gerd-Christian
• Is Part Of: Journal of environmental management. Volume 304(2022)
• Publication Date: 2022-02-15
• Subjects: Fermentation -- Carbon dioxide -- Methane -- Nitrous oxide -- Enterobacteria -- Clostridia; ANOVA analysis of variance -- DM dry matter -- FM fresh matter -- G grass -- G LW grass longer wilted (ca. 24 h wilting) -- G SW grass shortly wilted (ca. 20 h wilting) -- GHG greenhouse gas -- GWP global warming potential -- L lucerne -- LW longer wilted (ca. 24 h wilting) -- L LW lucerne longer wilted (ca. 24 h wilting) -- L SW lucerne shortly wilted (ca. 20 h wilting) -- SW shortly wilted (ca. 20 h wilting); Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2021.114142
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: Silage is an essential global feedstuff and an emitter of greenhouse gases. However, few studies have examined the formation of carbon dioxide (CO2 ), nitrous oxide (N2 O) and methane (CH4 ) during the ensiling process. This study aimed to record the course of gas concentrations in forage during the ensiling process and determine the temporal variation in the (microbiological) formation processes. Grass and lucerne, each with two different dry matter (DM) concentrations (four variants, each n = 3), were ensiled in laboratory-scale barrels (120 L). Gas samples were taken from the headspace of the barrels and analysed using a gas chromatograph. The measurement period included the first 49 days of the ensiling process and the measurement interval was 0.5–48.0 h. For all variants, a rapid increase in CO2 concentration and a one-time N2 O concentration peak was observed between ensiling hours 36 and 96. Lower DM concentration led to significantly faster CO2 production (p < 0.05). Lucerne forage and higher DM concentrations led to significantly increased N2 O concentrations (p < 0.05). The extensive measurements demonstrated that butyric acid formation by clostridia contributes to CH4 formation; thus, lucerne silage had a significantly higher concentration from ensiling day 13 (p < 0.05). Therefore, malfermentation actively contributes to the formation of greenhouse gases. The method described here provides further insights into greenhouse gas formation during the ensiling process and can thus help to improve ensiling research and management. Graphical abstract: Image 1 Highlights: Greenhouse gas concentrations were monitored during the ensiling process. Within 49 days, 82 gas samples per silo were analysed using gas chromatography. For all variants, initial methane and nitrous oxide peaked within the first 4 days. Butyric acid formation within lucerne silage causes methane formation. Gas concentrations in silos can be used as an indicator of ensiling quality.