How nitrogen can be utilised better

Mineral fertilisers are the greatest source of nitrogen in agriculture, but there are also large amounts of nitrogen in manure. Measures that improve the utilisation of this resource are beneficial for both food production and the environment.

The biggest losses of nitrogen occur as ammonia from livestock manure during spreading in barns and during storage.

“Strip spreading and mixing with water significantly reduce ammonia losses compared to broad spreading of manure with high dry matter content," says Dr Synnøve Rivedal at NIBIO.

Sealing roofs where manure is stored is another measure that helps reduce losses. In addition, spreading manure during the growing season reduces runoff and increases nitrogen utilisation. Other relevant measures in livestock farming include tailored protein feeding, operational optimisation, reduced roughage waste, use of pasture, and new recycled protein sources.

Any conditions that provide better growth conditions for plants, such as irrigation, drainage, improved soil health, and less weeds, will result in increased nitrogen utilisation.

“At the same time, it is important to have a fertilisation plan that takes into account local growth conditions," says Dr Randi Berland Frøseth.

A measure that reduces leaching of nitrogen from fields is to cultivate catch crops that can absorb nitrogen after the grain is harvested. This will increase nitrogen efficiency if combined with reduced use of mineral fertilisers in subsequent years.

“Another measure for increased nitrogen efficiency and reduced nitrogen losses to water, which also has a good effect on soil and phosphorus loss, is to avoid ploughing in the autumn," says Marianne Bechmann.