Blog Post

Located just outside Paris, the French FENIX site in Dourdan offers a strong contrast to the project’s Mediterranean locations. While sites in Spain and Greece are shaped by hot, dry conditions, Dourdan experiences a temperate climate with more regular rainfall and milder seasonal variation. This difference makes it an important reference point for understanding how biochar performs across diverse European environments.

The soil here is actively cultivated for cereal production, representing a typical temperate European farming system. As such, it provides an ideal setting to explore how biochar-based amendments can improve soil quality without compromising productivity.

A soil with untapped potential

The Dourdan soil stands out within the FENIX project due to its slightly acidic pH (around 6.6) and high silt content, both of which influence structure and nutrient behavior.

Although productive, the soil shows some limitations:

• Higher bulk density, associated with lower porosity
• Structural constraints that may affect root development
• Moderate water availability, with potential for improvement

Phosphorus dynamics at the site are also complex, as concentrations do not appear to be directly linked to pH, highlighting the need for site-specific management strategies.

Testing biochar for soil improvement

At this site, four types of biochar enriched with digestate are being tested. These trials aim to assess how different amendments affect soil properties and crop performance under real field conditions.

Because biochar is typically alkaline, it may have a liming effect on this slightly acidic soil, potentially improving nutrient availability. Meanwhile, the addition of digestate increases organic matter, which can enhance soil structure and biological activity.

Biochar’s porous structure is also expected to improve water retention and plant-available water, increase soil aeration and porosity and support more resilient crop growth

Towards more resilient European soils

The French site plays a key role in understanding how biochar-based amendments perform in temperate, intensively managed systems. While Mediterranean sites highlight challenges like drought and severe degradation, Dourdan represents a more widespread European concern: how to maintain productivity while improving long-term soil health.

By comparing results across climates and soil types, the FENIX project aims to develop adaptable solutions for sustainable agriculture. The insights gained in France will help guide strategies that strengthen soil resilience while reducing dependence on conventional inputs.

By: G. Carlson
April 2026