How can we ensure good soil health in Norway?

Soil health refers to the soil’s ability to support various ecosystem services, such as food production, water regulation, climate regulation, and biodiversity. Good soil health means that the soil is in sound physical, chemical, and biological condition.

Various degradation processes—such as erosion, loss of biodiversity, and pollution—threaten soil health, often because of human activity and climate change. According to the UN’s climate panel, one quarter of the world’s ice-free land area is already degraded. In the EU, 60–70 percent of soils are now considered “unhealthy.”

“Even though we lack comprehensive monitoring in Norway, the challenges are recognisable,” says Bøe.

“We see erosion leading to the loss of valuable topsoil, and soil compaction from heavy machinery damaging soil structure. In some areas, we also have excessive phosphorus levels, which can pollute our waterways, while organic carbon content is declining in regions dominated by cereal production.”

To address these issues and improve soil health, more knowledge is needed.

“Firstly, the knowledge base for assessing the physical, chemical, and biological condition of Norwegian soils is insufficient,” Bøe explains.

“Secondly, we know too little about how soil health improvement measures actually work under Norwegian conditions, with a relatively short growing season and high rainfall.”

These are the challenges Bøe has tackled in his doctoral work. By examining soil health at multiple levels—from regional analyses to farm-level comparisons and detailed plot trials—he provides a more holistic picture of both the problems and potential solutions.

Significant regional differences – and the need for tailored solutions

Bøe’s research shows that there is no single definition of “good soil health.” Soil types are shaped by climate, topography, and geological history, and vary from place to place.

“In Western Norway, for example, we often find soils with high organic content due to heavy rainfall, while soils in Trøndelag County and the Oslo region are more clay-rich due to marine deposits from the Ice Age.”

These differences affect the soil’s ability to retain water and nutrients.

“Assessments of what constitutes good soil health must therefore be adapted to local conditions, including soil type, climate, and farming practices,” says Bøe.

Research at multiple levels – from datasets to earthworms

At the regional level, Bøe tested a methodology for assessing soil health tailored to Norwegian conditions. Using a large database, he has developed the first region-specific reference curves for Eastern and Central Norway.

“This work is primarily a proof of concept. It shows that the methodology of reference curves works for establishing local benchmarks in Norway,” Bøe explains.

“In theory, the curves could be a useful tool for comparing soil health on one farm with others in the same region.”

However, Bøe emphasises that the work reveals clear limitations. The database mainly contains chemical data, so the curves provide a good picture of soil fertility but not a complete assessment of soil health.

“To get a full picture, we also need to include physical and biological properties. Additionally, the curves themselves need further development. Nevertheless, the work lays an important methodological foundation for future soil health assessments,” he says.

Sustainable practices improved soil structure and soil life

The inclusion of more physical and biological parameters was examined in field and plot trials.

A key finding comes from a detailed comparison of two neighbouring farms—one practising reduced tillage, cover crops, and diverse crop rotations over time, and the other using conventional methods. To place the results in a broader context, these two fields were compared with reference data from surrounding farms in the same region.

The results showed that sustainable practices led to better soil structure and more soil life.

“In the field with these practices, we measured four times as many earthworms compared to the conventionally managed field. This is a very clear result that shows the potential of such systems,” says Bøe.

He stresses that although this is a thorough case study, the findings need to be confirmed through studies on more farms to allow for generalisation.

Plot trials with cover crops

In collaboration with colleagues, Bøe also conducted plot trials with various cover crops, including at Tuv in Trøndelag County, to investigate the underlying mechanisms that contribute to healthier soil.

“The results show that cover crops like ryegrass can be established even in northern regions without reducing yields,” he says.

The choice of cover crops must be tailored to both the goals of the intervention and local growing conditions, as there is no one-size-fits-all mix.

The research shows, for example, that while all cover crop mixtures were effective at absorbing phosphorus, the fate of the nutrient in the soil appears to depend on the quality of the plant residues. Mixtures with high carbon-to-phosphorus ratio likely led to microbial immobilisation of phosphorus.

“At the same time, the most species-rich mixture was most effective at improving soil structure and promoting fungal life, while mixtures with extensive root systems were best at forming stable carbon over time,” Bøe explains.

“Practical considerations also play a role—sowing around harvest requires a long autumn, making spring sowing the safest option for most farmers in Norway.”

Measuring soil health requires more than chemical analyses

Bøe now calls for methods that enable more systematic and comparable monitoring of soil health over time and across regions.

“Today, Norway lacks a national framework for this. Current routines are often limited to chemical analyses such as pH and nutrient content, while important physical and biological indicators are often omitted,” he says.

Bøe believes that improving soil health in Norway is possible, but it must be done through locally adapted measures.

“Unlike many other countries, we already have a tool through the Regional Environmental Programmes (RMP). The system is already set up to support tailored measures,” he says.

By applying new knowledge, RMP can move from supporting general measures to rewarding the most effective solutions for the specific challenges each region and farm faces.

“If we are to ensure good soil health for the future, it also requires better monitoring, more research, and—most importantly—greater awareness of the role soil plays in food security, climate, and the environment,” Bøe concludes.