Soon to be published research from Teagasc shows there is no difference in ammonia emissions levels from slurry applied by a dribble bar or trailing shoe on short grass.

Dr Dominika Krol of Teagasc Johnstown Castle presented the unpublished research findings at the British Society of Animal Science (BSAS) conference 2025 in Galway this Tuesday.

As part of the experiment, which also looked slurry storage emissions, field trails were conducted in Johnstown Castle, Co Wexford, and in Loughgall, Co Armagh, by the Agri-Food and Biosciences Institute (AFBI), a project partner.

Slurry was spread at the two sites three times across both 2021 and 2022 using different application methods.

The study’s emissions measurements found 37% more ammonia emissions from slurry applied with a splash plate versus low emissions slurry spreading (LESS) methods.

However, there was no difference in emissions from different LESS application methods.

'No variance'

Speaking to the Irish Farmers Journal, Krol said emissions relate to the area covered by slurry. Therefore, from a dribble bar on short grass, with hoses close to the ground, there was no variance compared with the trailing shoe.

“In the work that we did in the 'Triple A' project – this is unpublished, we are still working on the results, that’s a caveat – we see that when we applied slurry with those two methods [dribble bar and trailing shoe] on short grass there is no difference.

“Applying to short grass, the trailing shoe and trailing hose will leave pretty much the same [slurry] bands. Now, there is obviously the potential for a differential in emissions if the grass is higher, because then the trailing shoe is equipped to part the grass and spread closer to the ground, whereas the trailing hose would just trail on top of the grass.

“For example, when the slurry is applied after a silage cut or animal grazing and that grass is quite short, they are very comparable.

“The other caveat with the dribble bar/trailing hose is that there is a flexibility in bringing the hoses, the outlets, to a higher level. That will then increase the spread area, so the bands will be wider. That will increase ammonia emissions.

“So we just need to be very careful with that. When the dribble bar is used correctly on short grass, the emissions are very comparable to the trailing shoe,” Krol added.

TAMS

In September 2024, dribble bar slurry applicators were officially ruled out of receiving funding under the Targeted Agriculture Modernisation Scheme (TAMS) by then-minister for agriculture Charlie McConalogue.

The long-running issue around dribble bars being excluded under TAMS first arose when the scheme opened in February 2023.

Following outrage from farmers, at the time McConalogue held meetings with machinery trade bosses on the move.