It is well recognised that Irish dairy farmers are among the most environmentally sustainable food producers in the world, according to William Burchill.
The Teagsac/Dairygold Joint Programme Manager said that despite this, recent revisions to both Irelands national greenhouse gas (GHG) and ammonia emissions targets will create a significant challenge to the Irish dairy sector going forward, he said at the National Dairy Conference.
Agriculture accounts for 32pc of Ireland’s national GHG emissions and virtually all national ammonia emissions (>98pc), he said. Agricultural GHG and ammonia emissions have increased in recent years and are projected to increase further in the future, he added.
“It will be ultimately up to individual farmers to come together as a sector to confront this challenge,” he said at the conference.
As a result, steps will need to be taken within the Irish dairy sector to reduce GHG and ammonia emissions while maintaining and improving profitability, he explained.
What are the sources of GHG and ammonia emissions on Irish farms?
The majority of GHG emissions come from methane gas produced by cattle, he said, adding that the remainder is associated with nitrogen fertiliser use and the management of livestock manures.
The sources of agricultural ammonia emissions differ to GHG, he said. The majority of agricultural ammonia emissions arise from cattle housing, cattle yards, slurry storage and application of livestock manure to land (92pc), he explained.
He said that nitrogen fertiliser use accounts for the remainder of agricultural ammonia emissions.
What can be done to reduce emissions?
A large range of options are available to reduce GHG and ammonia emissions and several are linked to the technical efficiency of the farm, he noted at one of the workshops at the conference.
Options that have the potential to improve farm profitability, while reducing GHG and ammonia emissions at the same time include;
· increasing the length of the grazing season,
· improving animal performance (through genetics and management),
· improving nitrogen efficiency (fertiliser timing, place, type and rate),
· altering the timing of slurry application from summer/autumn to spring time to reduce ammonia emissions is cost beneficial,
· the use of low emission slurry spreading techniques (trailing shoe or dribble bar) is a more expensive way to reduce GHG and ammonia emissions but has other benefits including reduced slurry contamination of grass and odour.
He also noted that recent research has shown that using ‘protected’ urea instead of CAN and urea will reduce emissions while giving similar annual grass dry matter yields but may increase farm fertiliser costs depending on the relative price of ‘protected’ urea.