Soil is as essential to human well-being as air and water. It is a key component of many ecological processes and assures the provisioning of ecosystem services such as food production, water depuration, carbon storage, crop resistance to pests and diseases.
Soil organic matter affects the biological, chemical and physical properties of the soil and therefore, plays a central role in maintain soil functionality and productivity. Especially, organic matter, contributes to prevent soil erosion and land flooding and can play a role in climate mitigation. Therefore, the steady decline of organic matter in many European soils is one of the biggest environmental threats.
The use of organic residues from different sources as soil amendment represent an opportunity to increase organic matter in the soil and strength re-use of resources.
Treatment of organic residues (e.g. composting, anaerobic digestion and fermentation) prior to land application is widely used to improve soil fertility. However, a complete understanding of the short and long term effects of these treatments on stabilizing organic matter in soil is still lacking.
The Wetsus soil theme investigates the effect of organic residues on soil organic matter with the aim to promote the reuse of organic residues, strengthening circular economy and increase soil fertility.

Currently, three PhD projects are involved in the Wetsus soil theme.
One project focuses on identifying the chemical and microbial structure of organic residues and relate it to the changes in soil microbial community. The project aims to select organic residues to promote or reduce specific groups of microorganisms in the soil that are beneficial for organic matter stabilization and crops growth.
The second project focuses on identifying the key physical, chemical, and biological parameters involved in the treatments of organic residues and how they can be engineered to increase organic matter in soil.
The third project focuses on phosphate recovery during anaerobic treatment of manure from digestate.
Relying on the gained insight, the Soil Theme will investigate how to integrate knowledge and expertise of Wetsus on water treatment technology to find most suitable form of organic matter addition for agricultural application.

Team members

Coordination & management
Valentina Sechi

Valentina Sechi

Theme coordinator Soil
Jan Feersma-Hoekstra

Jan Feersma-Hoekstra

Theme manager
Research staff

Research documents

Research partners