How deep do microplastics travel through soil — and what does that mean for our food, water, and environment?
At Wageningen University’s Unifarm, a unique field experiment launched in spring 2024 is starting to provide answers.

To capture these complex interactions, the research team applied three types of plastics, including two that are certified biodegradable in soils, alongside a control treatment. Sampling is carried out at three depths, with five replicates, and repeated twice per year — totaling 120 samples annually.

Sampling campaigns are taking place in:

• May 2025 – Completed
• September 2025 – Completed
• May 2026 – Planned
• September 2026 – Planned

Meanwhile, the plastic analysis validation is ongoing, with extraction and identification of microplastics scheduled from October 2025 to April 2026. This rigorous workflow ensures reliable data on both the quantity and the characteristics (size, shape, degradation state) of microplastics at various soil depths.

The outcomes of SOILPROM reach far beyond academic curiosity. They are directly relevant to key ecosystem services (ES), including:

1. Food production – Understanding how microplastics interact with roots and soil fertility.
2. Water contamination – Assessing potential risks for groundwater and surface water quality.
3. Water infiltration – Evaluating whether plastics alter soil’s ability to absorb and retain water.
4. Air quality – Exploring possibilities of resuspension of plastics through wind erosion.
5. Genetic resources – Investigating impacts on soil biota and microbial gene exchange