data_PPP-MS-2024-01212.xlsx

Solar parks, large-scale arrays of photovoltaic panels, are a unique land use and play an important role in the renewable energy transition. However, the solar panels create shade and change the microclimate, potentially affecting plant growth and carbon inputs to the soil. These changes can influence key soil properties critical to long-term carbon storage and overall soil health. This study investigated the impact of commercial solar parks on plant productivity and the colonisation of roots by mycorrhizal fungi, soil organic matter (SOM), soil microbial community biomass and composition and litter decomposition in 17 solar parks with contrasting shading levels across the Netherlands.Soil samples and plant biomass samples were collected between and below the solar panels. The microclimate (temperature, moisture) was measured continuously over the growing season and cumulative solar irradiation during the growing season in relation to the solar panels was modelled.Results show that above- and belowground plant biomass as well as mycorrhizal colonisation were significantly lower below than between panels, while we did not find differences for SOM, carbon stocks and hot water extractable carbon. Plant productivity related negatively to the extent of light interception by the panels. Furthermore, fungal and bacterial biomass and the F:B ratio were lower between compared to between the panels while decomposition rates did not differ.The severe decrease of plant biomass inputs in combination with maintained rates of decomposition are expected to result in decreased SOM stocks and soil health over time and suggest the need for guidelines for ecologically sound solar park designs to prevent soil damage.