Sixty-year-old farmer Trevor Crowley, who milks 160 Friesian cattle with his 23-year-old son Gavin on the family farm at Hornhill, Lissarda, in mid-Co Cork, believes farmers can solve the climate-change challenges they face without culling the national herd.
Crowley won the top award for Reduced Carbon Footprint in the dairy category of Bord Bia’s Dairy Origin Green Farmer Awards in 2018, and since then he and his son have continued to reduce their carbon emissions
The first step came accidentally, he says, after he introduced a new aeration system in his three slurry tanks, which had previously required a day’s agitation by the older system before the slurry inside was in a fit state to spread on his lands.
So he began to look for less labour-intensive alternatives, soon finding an aeromix system developed by a British pioneer, Mike Ross, which periodically pumps through a series of pipes placed at the bottom of slurry tanks. The systems was installed in the early 2000s for €12,000.
“Every so often the flaps in the pipes open to let the air out and as the air bubble rises to the surface it churns the slurry, thereby mixing it so you are removing the need for mechanical agitators and it lowers the likely gas build-up,” he says.
Firstly, the tank is much safer to use, but the aeromix system, costing less than €2 a day to run, significantly cuts ammonia emissions which represent a major loss of valuable nitrogen for plant growth that costs farmers over €130 million annually.
Ammonia is a gaseous form of nitrogen and contributes indirectly to greenhouse gas emissions. Reducing emissions during both storage and spreading has major benefits, says Mike Earls, the managing director of Easyfix, which services Crowley's system.
Agriculture accounts for a third of the State’s greenhouse gas emissions, and for 99 per cent of ammonia emissions. Manure storage, in turn, accounts for 48 per cent of this figure, and slurry spreading for just over a quarter of it.
The aeromix can cut ammonia emissions in half, says Crowley.
Meanwhile, he has seen other benefits. “We’ve used no phosphate, or potash on the farm in the last 15 years – this system has cut our use of fertilisers by 25 per cent, so it’s a saving of about €8,000 a year.
Ammonia emissions
Crowley spent €45,000 in 2015 on a 2,500-gallon slurry spreader with a trailing shoe to spread the slurry, which cuts the ammonia emissions created by spreading by 60 per cent compared to the more traditional splash plate method.
“Spreading the slurry with the splash plate blows it up in the air whereas where you have a trailing shoe it involves parting the grass and running it along the top of the soil and putting the slurry directly on the soil, so it’s far more effective and efficient.
“With this you can spread slurry at the drop of a hat if the weather allows, and it has also led to better grass yields – we are now getting 12 tonne of total dry matter production per hectare compared to eight tonnes 20 years ago – that’s down to reseeding and better nutrient balance.”
Meanwhile fields can be grazed within three weeks of slurry-spreading compared to “nearly six weeks” before, while all now have vastly-improved soil index readings, illustrated by a dramatic rise in the number of worms compared with the old system which left them dead on the surface.
And the benefits go on.
Grass-growth is now so much better that Crowley and his son can keep cattle out for much longer, housing cattle for just six weeks a year, cutting housing costs but also leading to reduced methane emissions.
“My animals now are only fully housed from about December 1st until January 15th, when they start calving – there are shoulders at both ends when they are out part-time grazing, but it’s a big reduction from when they used to come in on October 20th and go out on St Patrick’s Day.”
Meanwhile, the new slurry-spreading system – which keeps the slurry close to the ground and not in the air – means that odours are far less offensive, making spreading possible within 10 metres of neighbouring houses without them noticing smells.
In all the changes mean that the farm’s carbon footprint has been cut from 1.26kg per kilogramme of milk solid in 2015 to 1.09kg per kilogramme of milk solid last July despite increasing his milking numbers from 100 to 160.
Adapt
Crowley believes farmers can adapt and not face disastrous cattle culls.
“When I took over from my father milk quota was the big thing, and I had to buy, borrow and beg to get our quota up to 100 cows.
“If we had to cut the herd now by a third we would probably be cut down to around 110 cows, and that would not be viable for Gavin and myself to survive. This broad brush of culling the national herd is just too easy – there are other options.
“My great-granduncle bought this farm in 1877 for £700, and Gavin is the fifth generation to farm it. There is a sense of duty not to be the generation that sells out, and the older I get the more conscious I am of that sense of continuity.
“We are all just custodians of the land. We all leave our mark on the land, but all we want to do is make a living out of it and pass it on, and do it in as environmentally-friendly way as possible.”
