Ground-mounted solar farms have become a familiar sight across the UK’s agricultural landscape. While they are important in reducing carbon emissions, their overall impact on the land they are built on remains uncertain. A new study from Lancaster University Environment Centre examined some of these effects and how they could be addressed.

Dr Fabio Carvalho, Professor Alona Armstrong and Dr Stuart Sharp, working in partnership with ecological consultants Clarkson & Woods and scientists from the University of York and UKCEH, as well as other Lancaster University researchers, examined 32 solar farms during the summer of 2021 to assess plant cover, soil health, and overall ecosystem functionality. Their analyses focused on three key areas within and around solar farms: directly beneath the solar panels, the gaps between panel rows, and adjacent pastureland, which served as a control.

Plant growth and biomass were significantly lower beneath the solar panels than the gaps between them or open pastureland, a reduction attributed to decreased sunlight and changes in the microclimate under the panels.

Soil health was also affected. The ground directly under the panels was more compacted, with implications for water infiltration and root growth. It contained lower levels of organic carbon and particulate organic matter (likely due to reduced plant productivity), essential for soil-related ecosystem services (e.g., soil carbon storage). The legacy of past agricultural activity was also evident, with relatively high concentrations of plant-available nitrogen and phosphorus in solar farm soils.

The researchers proposed several strategies to reduce the ecological impact of solar farms. Raising the height of solar panels or widening the gaps between rows would allow more sunlight to reach the ground, promoting plant growth, though overall implications for land use must be considered if changes to solar farm design result in an increased requirement for land. Additionally, planting shade-tolerant vegetation beneath and around the panels could enhance ecosystem health. Regardless of the approach, the researchers stress the importance of routinely monitoring soil conditions to detect and address issues like compaction or nutrient imbalances at an early stage.

Dr Carvalho said: “Studies at this scale are still scarce in the scientific literature and much uncertainty remains as to the long-term impact of solar farms on plants and soils. We must continue to monitor progress, including plant and soil responses to different land management practices within solar farms, and find solutions to promote plant growth beneath solar panels. Academia, industry and policy must work together to implement best practices and ensure solar farms can provide climate solutions and benefit nature together.”

By continuing environmental research into solar farm design, construction and management, researchers, policymakers and developers can implement solutions to generate clean energy without damaging the health of local ecosystems.

The full paper, published in Environmental Research Letters, can be found here