Soil protection measures can make agri-photovoltaics more sustainable

Agri-photovoltaics integrate electricity generation and agriculture on the same land. For long-term success, soil health is crucial. Researchers from the Leibniz Centre for Agricultural Landscape Research (ZALF) measured soil structure changes during the construction phase for the first time. Their study, published in Scientific Reports, found heavy machinery can compact soil so severely that plant roots have difficulty growing.

Targeted soil protection measures during construction can largely prevent this compaction. The team examined a new agri-photovoltaic plant at ZALF's research site in Müncheberg, Brandenburg. After construction, soil samples revealed significantly higher subsoil density (1.67-1.99 grams per cubic centimeter) compared to uncompacted areas (1.14-1.34 grams per cubic centimeter).

This reduced soil resistance to root penetration by up to 4.1 megapascals. Sandy soils, which make up the majority of the study site, struggle to recover after compaction due to weak structure and low carbon content. Compaction reduced winter rye yields by 22-43% at similar levels. Researchers recommend standard soil supervision during construction, using measures like restricted vehicle traffic, ground protection plates, and avoiding damp ground work.

Despite high costs, the study highlights the potential negative impact on soil fertility without proper protection. Further research is needed on other soil types and system configurations, as well as long-term soil recovery monitoring.