Solar farms are becoming an increasingly common sight across the countryside as the world transitions from fossil fuels towards more renewable sources of energy.

Researchers from Lancaster University’s Environment Centre and Energy Lancaster have published new data showing solar farms can do more for the environment than simply generate energy. In a systematic review recently published in Environmental Research: Ecology, researchers Dr Fabio Carvalho and Professor Alona Armstrong have shown they might also tackle other environmental challenges, such as restoring soil health and capturing atmospheric carbon.

Most solar farms in the UK are installed on agricultural land, often replacing conventional crops with managed grassland. While this might appear to be a compromise, properly managed grasslands have the potential to store more carbon in the soil than they lose. A review of the literature on grassland management in the UK and Ireland over the past 35 years identified several practices that could significantly boost soil health and its ability to store atmospheric carbon.

Encouraging a wider range of plant species.

• Planting a diverse range of native wildflowers, particularly those that thrive in shady conditions, may improve carbon storage and support a variety of other wildlife, benefiting both the local site and the broader environment.

Using low-to-moderate grazing intensity.

• Techniques like rotational grazing where livestock are regularly moved between different pastures can give the land time to recover, boost plant growth and diversity and increase the soil’s capacity to capture carbon.

Using organic fertilisers tailored to the specific needs of each site.

• Conservation cutting and rotational grazing together with moderate levels of organic nutrient addition and the maintenance of an optimum soil pH level can lead to positive outcomes for grassland soil carbon storage in the long term.

Managing soil health under solar farms is not without its problems. The efficacy of these approaches depends on local conditions, such as soil type, climate, and the types and quantity of vegetative cover. Shade cast by solar panels can reduce plant growth, especially under the panels, so choosing shade-tolerant plant species is key. Heavy machinery for mowing or fertilisation could compact the soil, reducing its ability to store carbon. And while grazing on the sites is a popular practice, farm operators must ensure livestock do not damage the panels or associated infrastructure.

Despite these hurdles, managing the grasslands on and around solar farms offers a unique opportunity. After the oceans, soil is the world's largest active carbon store, holding far higher quantities of carbon than the atmosphere, and 80% of all terrestrial carbon dioxide. Healthier soils can draw more carbon from the atmosphere, helping to mitigate climate change while improving soil fertility for future agricultural use. Additionally, the long operational lifespans of solar farms – typically 25 to 30 years – means land can be actively managed for decades, allowing long-term improvements in soil health to take root.

Dr Carvalho said: “Managing grasslands for soil carbon is challenging given the complexities involved in plant-soil interactions and how context-dependent soil responses are to management intervention. While our review has shown some practices to be broadly beneficial for grassland soil carbon in a UK context, solar farm operators must consider local conditions and constantly monitor progress to assess the success of land management practices for increasing soil carbon storage.”

As solar farms increase in number and size, this research offers a model for balancing energy production with ecological restoration. However, the researchers stress these benefits will only be realised if active monitoring and adoption of appropriate land management strategies are applied to solar farms across the UK.

Prof Armstrong said: ‘As the impacts of the climate and ecological emergencies become increasingly apparent, we need to do all we can to mitigate both. Using solar farms to reduce carbon emissions associated with electricity production whilst managing them for nature where possible, including soil carbon sequestration, is an opportunity we shouldn’t miss.”