New soils with reduced carbon footprint

In the project "Circular Soil Mixtures," NIBIO has collaborated with Asplan Viak and the College for Green Development. NIBIO has contributed with expertise on soil and vegetation, as well as material assessments, design, and testing of soil mixtures.

Soil with bricks, compost, and biochar

In the project, two circular soil mixtures were developed for use on roofs, and two for use in landscaping. The mixtures are different but are based on components such as local surplus masses from construction sites, various, compost, crushed bricks, and biochar.

“A crucial part of the project has been to reduce carbon emissions from soil production,” says NIBIO researcher Dr Hans Martin Hanslin.

“Calculations in the project clearly showed that the incorporation of biochar and reduced transport were important to achieve this.”

More than 20,000 buildings are demolished annually in Norway, and in 2021, the construction and demolition industry accounted for 25 percent of all waste in the country. Increased local reuse will reduce the carbon footprint in the construction and demolition sector.

Tested for six months

The mixtures have been thoroughly tested for six months, however large-scale trials remain.

“We are pleased to have identified soil mixtures that seem to work well for the desired vegetation and meet the requirements for physical and chemical properties for both roofs and landscapes,” says Dr Hanslin.

The main challenge is finding recycled materials that either directly or after refinement comply with regulations while contributing to good growth conditions. High pH in the materials has been particularly challenging to address.