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Luke in the forefront accelerating efficient and safe use of recycled fertilisers in Europe

News 3.5.2023

Manure, sludge and many other side streams do contain nutrients, but can they replace imported fossil fertilisers in Europe? This is what European researchers are finding out in a research project of 20 partners, led by the Natural Resources Institute Finland (Luke) from its research centre surrounded by experimental fields.

European farmers depend on imported fertilisers, the production of which uses non-renewable natural resources and a lot of energy. For example, phosphorus is dug from the ground, and natural gas is used to produce nitrogen. These top nutrients in cultivation are, however, also found in manure, sludge and plant waste and other side streams of agriculture, food industry and water treatment plants.

Lannoitetta kädessä.

 

"The production and use of recycled fertilisers is held back by the fact that nutrient concentrations in side streams are usually not particularly high, and their formation is concentrated regionally," says Kari Ylivainio, senior scientist at Luke.

One obstacle to the wider use of recycled fertilisers was removed last summer, when the free movement of CE-marked fertilisers became possible within the EU. Whether transportation makes economic sense is another question, and Luke's researchers are looking into it, among other things, with 20 European partners in the five-year EU-funded Lex4bio project. Luke's researchers are also finding out how much raw material suitable for recycled fertilisers is available in Europe.

"Many excellent recycled fertilisers are already being produced in Europe. They have the same high nutrient content as mineral fertilisers, and they are easy and safe to use." This has been studied in the Lex4bio project in extensive cultivation experiments in fields and greenhouses in eight different countries.

New information on the effectiveness of recycled fertilisers from Luke’s experimental fields

Luke’s research centre with experimental fields and laboratories is located in the Southern Finland, in Jokioinen. This is where also Ylivainio, who leads the Lex4bio project, works. Researchers have, for example, access to 860 hectares of fields, greenhouses, a test platform for smart farming, a research barn, and a pilot hall for the development of plant-based products.

"In the Lex4bio project, we tested nitrogen and phosphorus fertilisers with different properties on a field scale. Even though the smallest test plots were only 2.5 x 10 meters, we used the same methods and tools that are usually used in cultivation," Ylivainio says.

The project researchers measured the effect of each fertiliser on the quantity and quality of the harvested crop. According to Ylivainio, it was important, especially for the phosphorus experiment, to find a field block where phosphorus fertilisation would be needed to improve yields.

The selection of field blocks is facilitated by the land use information that Luke has been collecting from its experimental fields since the 1980s.

"Furthermore, a special feature of Finland is that farmers throughout the country have the phosphorus content of their soil tested every five years, which helps to put researched knowledge into practice."

Recycled fertilisers could largely cover Europe's need for phosphorus

In the Lex4bio project, the phosphorus content of European farmland was also analysed in order to determine the need for fertilisation.

"We estimated that 72 percent of European farmland does not need phosphorus fertilisation at all. In addition, most of the need for phosphorus fertilisation can be replaced with recycled fertilisers. However, we will further refine this estimate as the project progresses."

The results of the project are expected a year from now when the project ends.

"We want to provide comprehensive information on how recycled fertilisers produced in Europe can be used to replace imported fertilisers."

Who's leading the project?

Kari Ylivainio became familiar with field work already as a child on the family's dairy farm. He learned that the use of manure gave the fields an excess of phosphorus but not enough nitrogen, so mineral fertilisers were needed too. He has searched for new solutions to this equation, among other things, throughout his career as a plant nutrition researcher and leader of research projects.

The European Lex4bio project started shortly after Ylivainio had completed the project on recycled fertilisers in the Baltic Sea region.

"Our project has aroused interest of researchers across Europe and also outside Europe, and I now get to know, and even participate in, their research. It is rewarding to exchange ideas inside and outside the project, and finally also face-to-face. After all, the project fell right in the middle of the Covid restrictions."

Text: Marianna Salin