Agriculture is often categorised as a significant contributor to greenhouse gas (GHG) emissions in Ireland, with farms coming under increasing pressure to reduce emissions.

According to Teagasc, one of the most effective and simplest ways to reduce both ammonia and GHG emissions is by switching from straight fertiliser such as calcium ammonium nitrate (CAN) and urea, to a urea protected with N-(n-butyl) thiophosphoric triamide (NBPT).

Nitrous oxide loss from soils is a very important contributor to GHG emissions from agriculture. Nitrous oxide as a GHG is approximately 300 times more potent than carbon dioxide.

Urea protected with NBPT has the double benefit of cutting ammonia emissions and improving air quality. Ammonia accounts for 90% of agricultural emissions in Ireland currently.

Many farmers would have had concerns regarding the effectiveness of protected urea and its ability to grow grass compared to straight fertilisers. Teagasc has recently completed a study which compared the effectiveness of NBPT versus straight fertilisers.

Herbage production

A grazing plot study was carried out by Aine Murray, a researcher from Teagasc Moorepark, comparing the herbage production between CAN, urea and urea protected with NBPT at four site locations over two years.

Site locations: 

  • Moorepark Fermoy, Co. Cork in 2019 and 2020;
  • Clonakilty, Co. Cork in 2019 and 2020;
  • Ballyhaise, Co. Cavan in 2020;
  • Athenry, Co. Galway in 2020.

The study found there was no difference in the production of herbage dry matter (DM) per ha between the three fertiliser types over the two years at any of the locations used in the study.

Urea protected with NBPT has consistently produced the same grass growth pattern as CAN and urea across the year at the four sites.

Teagasc outlined that over the two years it has experienced no practical issues with using urea protected with NBPT and now sees it as a front runner for Irish agriculture to reach its GHG and ammonia emissions targets.