Agronomy Advice
April 21, 2023

Spotlight on Ammonia

There’s been a lot of news, research, advice and speculation on ammonia and its impact on the environment.

Farmer in a field with a sunset setting
Farmer in a field with a sunset setting

Here we try to unpick the important points and highlight the impact for farmers.

Defra’s consultation on reducing ammonia emissions from solid urea fertilizers was concluded in Jan 2021 and recommendations published in Mar 2022. Their recommendation calls for self regulation via a new Red Tractor standard.

To comply with this new standard farmers will have to restrict the use of straight urea from 15th January until the end of March each year and any further urea treatments throughout the year to be products that are treated/protected with inhibitors. Originally due to be rolled out this year, it has now been delayed until 2024.

Yara have always recommended  the use of Ammonium Nitrate(AN) or Calcium Ammonium Nitrate (CAN) fertilizers over straight urea for very good reasons: with AN/CAN you’ll always achieve a higher nitrogen use efficiency rate which means you’re making better use of your nitrogen investment as less nitrogen is being wasted through volatilisation. Volatilisation is the loss of nitrogen into the atmosphere. This is the other problem with urea fertilizers, because of the high level of volatilisation, it pollutes the air around us, ultimately affecting human health.

Bar graph of Emission Factors of Nitrogen Applied

Did you know that over 72% of ammonia emissions from fertilizer applications are caused by urea and UAN? By contrast, ammonium nitrate generates 90% fewer ammonia emissions per unit of nitrogen than urea.

Ultimately, Defra’s consultation backs up the science we’ve used to advise farmers for years - urea is an inefficient fertilizer, for increased returns and better accuracy farmers should invest in AN or CAN.

For a full explanation of the science behind this we’ve got a webpage dedicated to explaining it all for you.