31 October 2018

Farmers able to cut 25% of nitrogen costs


A new way to map fields can reduce nitrogen runoff while financially benefitting large numbers of farmers. This is the premise behind a significant new Danish innovation project with which the University of Copenhagen is involved.

How do we ensure that farmers have access to good production conditions while meeting EU requirements to reduce aquatic nitrogen emissions by 2027? A team of researchers from the Geological Survey of Denmark and Greenland (GEUS), Aarhus University and the University of Copenhagen are working to find a solution. The research and innovation project - MapField - is supported by 18.9 million kroner from Innovation Fund Denmark.

Farmers apply more nitrogen to soil than crops can absorb. The excess fertilizer nitrogen is then leached from their fields and either converted naturally through geochemical processes, or released into aquatic environments.

The MapField project researchers have succeeded in developing a technology that can identify how much nitrogen is converted in a field naturally, within meters of accuracy, and how much ends up in aquatic environments. While the ability of subsoil to retain and transform nitrogen varies from area to area, detailed overviews of fields and their nitrogen retention capacities are lacking.

"MapField maps the subsoil in individual fields, so that one is able to pinpoint areas where nitrogen is being leached. Currently, we can only look at 1500-hectare areas, but wide variations can exist in these 1500 hectares. MapField allows us to zoom in, one hectare at a time," explains Associate Professor Brian H. Jacobsen of the University of Copenhagen’s Department of Food and Resource Economics.

The project provides a technical basis for implementing targeted nitrogen regulations for agriculture, as adopted and now prescribed by the Danish Parliament.

MapField must evolve into a product within three years, one available for local authorities, farmers and the Danish Environmental Protection Agency – and for any other country that seeks more detailed mapping and better targeted regulation.

There is money in targeting nitrogen

With a more accurate understanding of field subsoils, one can improve targeted fertilization. Professor Jacobsen explains, "As a farmer, if you find out exactly where nitrogen is and isn’t leaching from your land, you are able to more effectively target use. You can then supplement in areas where you know that nitrogen will be effective, and maybe settle for seeding five hectares of catch crops instead of eight. Analyses have demonstrated that some farmers can save up to 20-25% of their current nitrogen costs."

Thus, reducing the amount of nitrogen released into aquatic environments while saving money is possible. "Debates are often framed around asking whether benefits will be best for the environment or farmers. Our point of departure is that there needs to be savings for farmers and improvements for the environment," says Jacobsen.

He underscores that not all farmers will benefit equally from the MapField method. The greater the variations in nitrogen retention, the greater the gains will be through improved targeting.