ASA members and farmers from all over Ireland met in Johnstown Castle, Co Wexford, yesterday to hear from Teagasc researchers and advisers on issues affecting nutrient management and new technologies aimed at improving the agricultural response to climate change and more efficient use of fertilisers.

CAN (27% nitrogen) is the most popular form of straight nitrogen fertiliser used on Irish farms, but it should not be used at this time of the year.

Calcium ammonium nitrate (CAN), while the most popular, is very susceptible to be lost to the atmosphere as nitrous oxide.

If it rains, it can be lost by leaching much easier than other forms of nitrogen.

So the message is don’t use CAN in January or February for early nitrogen applications.

So urea is a better bet at this time of the year.

Yes, you can get ammonia losses to the atmosphere when you use urea, but it is cheaper per unit of nitrogen than CAN and less prone to losses in January and February.

Alternatively, protected urea has been used in plot trials in Johnstown Castle and the results show it reduces losses of both ammonia and nitrous oxide.

The plot trials showed the grass yield was the same, ammonia losses were reduced by 80% compared with urea and nitrous oxide losses by 60% compared to CAN.

Larger field trials have started in Johnstown and Curtins Farm in Moorepark, but no detailed results have been released yet.

Teagasc Johnstown researcher Dominka Krol said: “In our plot trials, we have shown very little difference in grass yield between the three products – urea, CAN and protected urea. We have however seen very significant potential environmental savings.

"Some new trial work is ongoing to establish if we can pick up any residues, etc, in outputs from cows grazing swards where protected urea has been used.”