Phosphorus adsorption in a degraded soil under forestry recovery after bauxite mining in Paragominas, eastern Amazon, Brazil

Abstract

AbstractThe availability and retention of phosphorus (P) in soils under recovery process after mining operations play an important role in the management of this nutrient. The objective of this study was to evaluate the P adsorption in a reconstituted soil as a function of two forest recovery processes after bauxite mining. We evaluated three systems: native forest (FOR), planting of forest seedlings after bauxite mining (TPL), and natural regeneration of vegetation after bauxite mining (NRV). In each system, eight sampling plots were deployed. In each plot, we collected litter and soil samples. The soil samples were collected at depths of 0–5, 5–10, 10–20, and 20–40 cm, for soil chemical analysis and adjustment of P adsorption isotherms. We also performed an inventory of the tree vegetation to obtain basal area (G) and species diversity (H′). Forest was significantly superior with respect to most soil fertility, litter, and vegetation attributes, followed by natural regeneration and planting. In general, the adsorption curves and maximum phosphorus adsorption capacity (MPAC) in soil followed the order planting > natural regeneration > forest. We observed a negative relationship between phosphorus adsorption and soil organic matter, potential acidity, and available phosphorus. This result highlights the importance of biomass conservation and maintenance to ensure phosphorus availability in reclamation practices. Furthermore, such results indicate that both soil cover and plant species diversity should be considered when selecting species to improve P availability for reclamation of mined areas.