Biogeophysical Soil Constituents Associated with Revegetation Success of Reclaimed Mine Tailings in Southern Arizona

Soil health properties essential to successful phytostabilization of reclaimed mine sites are poorly understood. Mine waste reclamation aims to stabilize waste and manage affected lands to support self-sustaining plant communities. A critical limitation to sustained vegetation success is that these "soils" are deficient in the biogeophysical components essential to sustainable plant development. We aim to improve revegetation strategies on lands impacted by mining through identification of soil health indicators that associate with successful plant establishment during mine waste reclamation to inform management practices. For example, soil microbial communities facilitate vital nutrient cycling for phytostabilization and can provide a direct indication of soil ecosystem development. In our temporal study, we analyze both above-ground and below-ground indices to observe how soil health from reclaimed mining waste develops over time in correlation with vegetation. Metadata including total DNA biomass and 16S rRNA bacterial gene abundance were quantified, in addition to physicochemical indicators such as total nitrogen, pH, soil texture, and electrical conductivity. This study analyzed four years of data from two tailings storage facilities in Southern Arizona that revealed significant differences in soil biochemical indicators. Total DNA biomass, 16S rRNA bacterial gene abundance, and total nitrogen showed significant temporal increases with successful plant establishment. We contend that these metrics demonstrate links between the biochemical and vegetation community development of these damaged lands, and can potentially be used as a predictive tool for evaluating long term reclamation success on active mining sites in arid ecosystems. Improved understanding of the biochemical development on managed reclamation sites can facilitate the advancement of technologies to enhance degraded land recovery, especially phytostabilization-based mine reclamation, making this technology more effective in sustaining long-term soil health goals.