Dual use of solar power plants as biocrust nurseries for large-scale arid soil restoration

Large portions of global arid lands are under severe, increasing anthropogenic stress, their soils progressively degrading or already degraded. The interventional regeneration of the natural cover of these soils—photosynthetic communities known as biocrusts that armour them against erosion and fertilize them—is currently regarded as promising for dryland restoration and sustainability. Technologies for biocrust restoration developed during the past decades are, however, invariably of high effort and low capacity, constraining application to small spatial scales. We tested the notion that crustivoltaics, where solar power plants are used as ad hoc biocrusts nurseries, can break this scaling barrier. We show experimentally that solar plants indeed promote the formation of biocrust over neighbouring soils, doubling biocrust biomass and tripling biocrust cover, and that after biocrust harvesting, recovery is swift particularly if re-inoculated. Our results point to a mode of continuous dual operation that is not only effective and socioeconomically attractive but can also increase capacity by orders of magnitude to reach regional scales.