Growth of beach-adapted plants in recycled glass sand compared to natural beach sand

Abstract Aims The goal of this study was to explore the suitability of recycled glass sand for the growth of beach-adapted plant species given the potential environmental benefits of utilizing glass sand for beach and dune restoration in the face of dwindling natural sand resources. Methods We grew three species native to US Gulf of Mexico beaches ( Ipomoea imperati (Vahl) Griseb., I. pes-caprae (L.) R.Br., and Uniola paniculata (L.)) in three greenhouse experiments in glass sand, beach sand, or mixtures. First, we investigated nutrient and microbial effects by growing each species in pure glass sand, beach sand, and 80%/20% mixtures of glass sand/beach sand. Second, we compared U. paniculata growth in glass sand mixed with 100%, 75%, 50%, 25%, or 0% beach sand. These experiments included fertilizer and microbial sterilization treatments. Third, we investigated soil permeability effects by comparing growth of all species using different grain sizes of glass sand. Results Overall, plants produced significantly more biomass in beach sand than in glass sand, and the effect was more pronounced with the fertilizer treatment. There were significant effects of substrate mixtures and interactions with fertilizer treatments on Uniola biomass. Further, when glass sand grain sizes were manipulated, plant biomass was equal or higher in the coarsest glass sand compared to beach sand. Conclusions Our results demonstrate that beach-adapted plants can grow in glass sand and suggest that recycled glass sand is a potential resource for ecological restoration with incorporation of soil amendments such as fertilizer and utilization of selected grain sizes.