On the Teagasc Research Farm at Solohead, an 1,100 gallons per acre dairy herd, stocked at 0.8 cows per acre, can be successfully managed on a grass clover sward, with a major reduction in nitrogen applications.
Researcher James Humphreys claims that increasing clover in the sward can reduce Nitrogen requirements by up to 50% without loss of production, and could enable more dairy farmers to qualify for a further income bonus through REPS payments.
He said the Solohead research farm can comfortably carry 0.8 cows per acre, using 70 units of nitrogen per acre per year.
He added, "Nine out of ten grassland farmers in Ireland are operating at similar or lower stocking rates. There are clear reasons why many of these farmers should consider introducing white clover into their grassland."
Cows on the farm produce 1,350 gallons per year. The key to the system is the white clover in the sward, which supplies about 70 units of nitrogen per acre per year. "We found the amount of fertiliser nitrogen required to carry 0.8 cows per acre can be halved from around 140 to 70 units per acre per year. Furthermore, the research data shows that the presence of the clover improves the nutritive value of the sward," he said.
Mr Humphreys said that a dairy farmer on 140 acres using white clover could save up to €3,500 in fertiliser nitrogen expenditure per year, and could qualify for REPS 3, worth an additional €8,550 per year.
He added, "On top of this, there is substantial scope for this farmer to expand in milk production while remaining within REPS. Using white clover allows this particular dairy farmer to have both REPS and expansion in dairying as options for the future."
He said the most reliable way to get the clover into the sward is through direct reseeding, but a cheaper alternative which has worked well at Solohead is to over-sow the clover into the existing sward.