Predicting soil recovery timelines in degraded mine lands using tree-based soil quality indices and asymptotic growth model.

Ecological restoration of degraded mine soils remains a challenge in restoration processes. Precisely identifying the restoration trajectory is crucial for evaluating reclamation success, informing adaptive management decisions, and predicting the ecosystem's future. This research suggests using a combined approach involving a tree-based Reclaimed Mine Soil Quality Index (RMSQI) and an asymptotic growth model to predict reclamation age in degraded mine soils. The study examined the soil physical and chemical conditions, biological activity, and enzymatic parameters under four dominant tree species: Dalbergia sissoo, Azadirachta indica, Tectona grandis, and Albizia procera. This was done at 5, 15, and 25 years after reclamation, along with assessments of non-planted soil and reference normal soil (RNS). As the age of the plantations increased, the RMSQI values rose from 0.230-0.249 at 5 years to 0.607-0.627 at 25 years. These values approached the RNS value of 0.656. Among the models used to predict RMSQI trends, the asymptotic growth model was the most accurate, with R2 values over 0.99. Monte Carlo simulations indicated the median recovery period could range from 29 to 34 years to reach the reference soil condition. D. sissoo showed the quickest recovery time, while T. grandis demonstrated high variability in recovery duration. These findings provide a solid foundation for predicting reclamation timeframes and choosing suitable species for successful mine rehabilitation projects.