Tillage conference: ‘The protected urea effect is for grassland’

Protected urea has been somewhat of a popular subject for the past number of years. There’s no doubt it can play a big role in reducing agricultural emissions, but where it fits best is on grassland.

When a question was asked on the use of protected urea on tillage farms at last week’s Teagasc National Tillage Conference, John Spink – the head of the crops, environment and land-use programme at Teagasc – took the microphone.

“The protected urea effect is for grassland,” John commented.

“If you look at the emissions of nitrous oxide from tillage land in Ireland, it’s about a quarter of when you apply to grassland. That’s because tillage land is generally drier, so you get lower nitrous oxide emissions.

All the messages to do with protected urea are focused on grassland and are not to do with tillage.

Earlier in the day, Karl Richards, from Teagasc Johnstown Castle, explained that improving nitrogen (N) use efficiency was the best way to decrease greenhouse gas (GHG) emissions from tillage farms. He explained that most other measures are to do with the livestock sectors.

A reduction in N fertiliser use can be achieved through the use of a good nutrient management plan, as well as the build up of soil organic matter through the application of organic manures, growing cover crops, straw incorporation and crop rotation.

However, where animal manures are being applied to tillage land low emission spreading and quick incorporation can significantly reduce emissions.

N losses

When calcium ammonium nitrate (CAN) and urea are spread on farms, there are three main ways that N can be lost – through volatilisation (ammonia), denitrification (nitrous oxide) and leaching (nitrate).