Soil protection in solar photovoltaic farms by revegetation with mycorrhizal native species

The installation of a photovoltaic solar farm involves modification of the original soil properties, which can be compensated for by revegetation of a proportion of the surface of the installation with native plants. Mycorrhizal plants can be used in the revegetation process because these plants are known to increase the structural stability of degraded soils and improve natural vegetation cover, thus increasing both survival and growth of the species, especially in semi-arid areas. The aim of the present study was to analyse mycorrhizal colonisation of native species to ensure success of revegetation in solar photovoltaic farms in Mediterranean areas. The present study was performed in the field because most studies on mycorrhizal species have been conducted in a controlled nursery environment. Four species were planted (Cistus monspeliensis L., Lavandula stoechas L., Thymus vulgaris L. and Rosmarinus officinalis L.) with inoculated and non-inoculated plants. Once the percentage of mycorrhizal colonisation of inoculated plants was known, the survival percentage and apical growth were determined over 2 years. The mycorrhizal colonisation of inoculated plants was satisfactory at the end of the study period, although there was a natural colonisation of mycorrhizae in plants that initially had not been inoculated. Lavandula stoechas L. had the highest survival percentage (95.8% in mycorrhizal plants and 100% in non-mycorrhizal plants) and Rosmarinus officinalis L. had the highest apical growth (19 cm in mycorrhizal plants and 15.2 cm in non-mycorrhizal plants). The species factor had a significant effect on survival percentage and apical growth of the species studied.