Construction-induced soil compaction in agri-photovoltaic systems: evidence from an Arenosol

Agri-photovoltaic (Agri-PV) systems, which combine crop production with solar energy generation, are rapidly expanding across Europe, yet their implications for soil quality remain poorly understood. This study assessed soil compaction following the installation of an Agri-PV system in autumn 2024 on an Arenosol in Brandenburg, Germany. Bulk density (BD) and penetration resistance (PR) were measured across multiple depths after construction finalization. Both parameters were compared to a nearby reference and established agronomic thresholds. Subsoil BD in construction zones (1.67-1.69 g cm⁻³) exceeded root growth thresholds, while PR at mid-depth reached 3.7-4.1 MPa, surpassing the limit for root elongation. Our results align with literature indicating that Arenosols, due to their weak structure and lack of shrink-swell capacity, are highly vulnerable to persistent compaction. The observed compaction poses risks to rooting depth, water infiltration, and crop yield, underscoring the need for targeted mitigation measures. We suggest that pedological construction supervision should become standard practice for Agri-PV projects, ensuring soil protection measures are integrated into planning, construction, and restoration. More flexible policy frameworks and monitoring of soil recovery post-installation are needed for aligning renewable energy expansion with sustainable crop production.