From side streams to products – Soilfood and Metsä Group collaborate to create recycled fertilizers and soil conditioners

Nitrogen and phosphorus are the most important raw materials for crop production—without them, there is no food. Typically, nitrogen is extracted from the atmosphere and processed into nutrients, which requires a lot of energy and causes significant emissions. Meanwhile, phosphorus reserves mined from the earth are depleting.

Recycled nutrients replace fossil-based nitrogen compounds and mined phosphorus, whose production is energy and emission-intensive. The use of soil improvement fibers and structural lime improves soil fertility and reduces nutrient runoff from fields into water bodies.

Returning nutrients stored in trees to the soil

Soilfood produces recycled fertilizers, soil conditioners, and structural lime from fiber-rich side streams and lime from Metsä Group’s Nordic mills.

With recycled nutrients, dependence on virgin natural resources can be reduced, agricultural environmental impact minimized, and nutrient cycling promoted. The collaboration between Metsä Group and Soilfood positively affects not only the efficient use of raw materials but also domestic food production.

“We want to promote the circular economy and need partners to do so. Our goal is that by 2030, none of our production side streams end up in landfills. Already, nearly all of our side streams are utilized as materials or energy. Our long-term goal is to increase the use of side streams as raw materials for products,” says Maija Pohjakallio, VP, Climate and Circular Economy in Metsä Group.

In 2024, Soilfood recycled approximately 260,000 kilograms of phosphorus from Metsä Group’s side streams to fields. The phosphorus fertilization need for crops in Finland is about 23.3 million kilograms per year. About half of this comes from animal manure, less than a tenth from other recycled sources, and the rest from industrial virgin fertilizers—i.e., mined phosphorus.

“Circular economy is not just improved waste management and recycling. The goal is to optimize material, energy, and information flows and value creation. Partners like Soilfood are important to us, and through our collaboration, some of the nutrients and carbon originating from trees are returned to the soil,” Pohjakallio explains.

“We share the goal of circulating as many side streams as possible forward as materials. This means finding the best possible reuse solutions that create value for the circular economy. In this product development work, Metsä Group is an excellent, sparring partner for us,” says Eljas Jokinen, CEO of Soilfood.

Healthy soil retains nutrients

Phosphorus and nitrogen are among the largest contributors to water pollution from agriculture. When excessive nutrients flow into water bodies, they accelerate eutrophication and increase algae growth.

In addition to recycled nutrients, Soilfood produces soil improvement fibers and structural lime from Metsä Group’s side streams. Soil in good condition retains water and nutrients better than poor-quality soil. Fiber and lime treatment can even halve phosphorus runoff from fields*. Moreover, healthy soil is more likely to produce crops under variable weather conditions.

For example, side streams from Metsä Board’s mills are used as soil conditioners on nearby farms.

“Domestic circular economy and good soil fertility are important parts of our food production self-sufficiency. They reduce our dependence on imported fertilizers. Last year, about 2,700 hectares of fields were treated with soil improvement fibers and structural lime refined from Metsä Group’s side streams. Through fiber treatment, approximately 1.6 million kilograms of bio-based carbon were added to the soil to improve its fertility. This truly makes a difference,” says Jokinen.

*Rasa, K, Pennanen, T, Peltoniemi, K, et al. Pulp and paper mill sludges decrease soil erodibility. J. Environ. Qual. 2021; 50: 172–184.