With 98% of our country’s ammonia emissions coming from agriculture, farmers are coming under increasing pressure to include protected urea in their fertiliser plans – in an effort to reduce our environmental impact.
Protected urea is simply normal urea coated with a urease inhibitor (NBPT) to reduce ammonia emissions. Unlike urea, protected urea can be spread during the main grazing season – essentially replacing the use of calcium ammonium nitrate (CAN).
During a recent Teagasc event held in Ballyhaise, Teagasc’s Brian McCarthy and Fergus Bogue were on hand to answer any questions farmers may have regarding the use of protected urea on grasslands.
The following are some of the questions which were asked on the day.
Is there any difference in yield from CAN vs. protected urea?
“No, there is almost no difference. Under the cutting trials in Johnstown there is no difference in annual dry matter (DM) production between the two.
Under the grazing plot trials, on average, there was a 300kg DM/ha difference between the two; so, very little difference.
Ballyhaise has been using protected urea for the last two grazing seasons. Touching on their experience with the product, Barry Reilly, the farm manager in Ballyhaise, said: “I can’t say we have grown any less grass from using it.
“We grew just shy of 14t/ha last year and we are on target to grow 15t/ha this year. So, we are quite happy.”
Are all protected urea products the same?
“No; not all protected urea products are the same. A protected urea product has to contain one of these active ingredients: NBPT; 2-NPT; or NPPT. If it doesn’t, it is not a protected urea product,” explained Brian.
Teagasc has recently released a list of recommended protected urea products (see below).
Image source: Teagasc
Can you spread lime at the same time as protected urea?
Unlike ordinary urea where you should leave approximately three months between spreading lime and applying urea, protected urea can be spread straight after applying lime.
“This is because the protected urea actually works better when the pH is good and the coating protects the urea against loss – improving its effectiveness,” explained Fergus.
Do you have to change your spreading strategy?
When moving from CAN to protected urea, yes, your spreader will have to be re-calibrated. It is important for farmers to refer to their fertiliser spreader handbook, as there will be different fertiliser spreader settings to get the application rate and the evenness of application correct.
However, moving from urea to protected urea, there is no difference. The only potential difference could be between the batches of urea fertiliser.
“One thing you can’t do, is spread phosphorus (P) with protected urea – because it is quite acidic and it will break down the coating on the protected urea product reducing its effectiveness,” highlighted Brian.