Phytomanagement improves soil aggregation and ecological security near tailings

Abstract

Aims Revegetation is an effective measure to improve soil structure and nutrients in erosion-prone areas. However, little is known about the impact of diverse phytomanagement of revegetation on soil quality and ecological security near tailings.Methods We investigated the water-stability and soil aggregate nutrients and assessed the associated risk of heavy metal contamination under multiple phytomanagement (natural grassland, artificial forest, and artificial forest mixed with shrubs and herbs) near abandoned tailings on the Loess Plateau, comparing with the adjacent bare land.Results The results showed that phytomanagement significantly enhanced soil aggregate stability, as demonstrated by the rise in soil macro-aggregate proportion (> 0.25 mm, 10.5–22.4%) and geometric mean diameter (16.3–44.0%). Furthermore, the soil organic carbon content (SOC), glomalin-related soil protein (GRSP), aromatic-C, and alkene-C in macro-aggregates increased alongside aggregate stability enhancement. The increased stability of soil aggregates following phytomanagement could reduce the risk of heavy metal leaching, but the increased concentration of heavy metals in the aggregates. In addition, the management of artificial forests mixed with shrubs and herbs greatly reduced the ecological risk of heavy metal pollution compared to other phytomanagement. SOC and GRSP were identified as key factors influencing the risk of heavy metal contamination in soil aggregates following phytomanagement.Conclusion Our study highlights that revegetation of tailings improves soil quality and ecological security by increasing the stability of soil structure as well as SOC and GRSP within the aggregates. Artificial forests mixed with shrubs and herbs could be an optimal phytomanagement to achieve environmental sustainability in tailings areas.