Influence of Manure Application Techniques on the Microbial Content of Grass and Grass Silage

Title (eng)
Influence of Manure Application Techniques on the Microbial Content of Grass and Grass Silage
Author
Samart Dorn‐In
Unit of Food Hygiene and Technology, Centre for Food Science and Veterinary Public Health, Clinical Department for Farm Animals and Food System Science, University of Veterinary Medicine Vienna, Vienna, Austria
Author
Hanna Geißler
Author
Katrin Harms
Author
Claudia Guldimann
Author
Hubert Spiekers
Author
Michael Diepolder
Author
Karin Schwaiger
Unit of Food Hygiene and Technology, Centre for Food Science and Veterinary Public Health, Clinical Department for Farm Animals and Food System Science, University of Veterinary Medicine Vienna, Vienna, Austria
Abstract (eng)
Field observations of visible dry manure residues in organically fertilised grassland, especially in drought areas in Bavaria (Germany), raised questions about whether different manure application methods influence the microbial composition in grass and in silages. Therefore, the aim of this study was to investigate if and to which extent three manure application methods (broadcast, trailing shoe and disc injector) and a control (mineral fertiliser) influence the microbial quality of grass and grass silage. The following samples were taken in two trial years (2020–2021): Soil (n = 16), manure (n = 10), wilted-chopped grass (n = 96) and grass silage samples (n = 80). The laboratory methods used were cultivation and qPCR. The comparison between the test groups showed no significant difference in the number of aerobic bacteria, lactic acid bacteria, Lactobacillus spp., Enterobacteriaceae, E. coli and yeasts in all sample types. The Clostridia load in soil and grass before fertilisation was similar in all test groups. After fertilisation, grass samples from plots fertilised with the disc injector method had statistically significantly lower Clostridia (2.6 log10 cfu/g) than samples from the trailing shoe (3.3 log10) and the broadcast (3.2 log10) but higher than the control group (1.7 log10) (p < 0.05). Clostridia counts in silages were between 3.7 and 3.9 log10 for the manure treatments and 3.3 log10 for the control. Except for the Clostridia levels in the grass, the results of this study indicate that the grass and silage from the three manure application methods were of similar microbial quality.
Keywords (eng)
BroadcastDisc InjectorFeed HygieneSlurrySoilTrailing Shoe
Type (eng)
journal article
Language
[eng]
Persistent identifier
https://phaidra.vetmeduni.ac.at/o:5115
DOI
10.1111/gfs.70019
Is in series
Title (eng)
Grass and Forage Science
Volume
80
Issue
4
ISSN
0142-5242
Issued
2025
Number of pages
13
Publication
Wiley
Version type (eng)
version of record (published version)
Date issued
2025
Access rights (eng)
open access
License
CC BY 4.0 International
Rights statement (eng)
© 2025 The Author(s)