New research on using plants other than grass in pastures show major environmental benefits and cost savings for farmers.
The research, carried out by UCD's School of Agriculture and Food Science, shows multispecies swards - which are composed of three or more species - greatly reduce the need for nitrogen application, produce more fodder and led to cattle reaching finishing age five to six weeks earlier.
Traditionally, Irish farmers aimed to produce grassy fields for their animals to graze, adding artificial or organic nitrogen to encourage plant growth.
In recent years however, all livestock farmers have been advised to move to multispecies swards, whereby herbs and legumes are grown along with grass.
These additional plants naturally absorb nitrogen from the atmosphere, deliver it into the soil, making it available to encourage pasture growth.
The research found that using a mixture of two grass species, two legumes and two herbs, in a multispecies pasture can result in a 60% reduction in nitrogen application, and a 25% increase in fodder production.
Applied to a 100 acre farm in a single production year, the research showed that a farmer could reduce nitrogen spreading by 4.6 tonnes, while also getting 100 tonnes extra of fodder for their animals.
The research, which is ongoing, also found that cattle consuming the multispecies sward, reach their target slaughter age five to six weeks earlier than animals grazing ordinary grass fields.
The earlier slaughter of cattle reduces the carbon footprint of beef by 15% per kg.
Reducing the application of nitrogen to pastures lowers greenhouse gas emissions and the risk of nitrogen run off into groundwater or water bodies. Reducing the finishing age of cattle also lowers the lifetime methane emissions of the animals.
The ongoing research is being supervised by Professor Tommy Boland at UCD's Lyons Farm, located on the Dublin-Kildare border.
"Irish agriculture is faced with important targets to enhance the environmental sustainability of the food we produce," Prof Boland said.
He added: "These include reducing Greenhouse Gas emissions by 25% by 2030, reducing the quantity of fertiliser nitrogen we apply and improving water quality and biodiversity in our farmed and wider landscapes.
"But in making these changes we need to be conscious of the economic and social sustainability of our farming practices also."
Prof Boland said the research into multispecies swards is still in its infancy, but "consistent positive findings show the potential it holds."
The findings of the research will be discussed at the annual conference of the Agriculture Science Association next month.
