Revegetation as a driver of chemical and physical soil property changes in a post-mining landscape of East Kalimantan: A chronosequence study

Abstract

As a result of mixing soil materials from various natural soil horizons, mine soils generally have low organic C and total N content. In wet tropical climates where the vegetation is evergreen, we hypothesize that with the start of revegetation, the organic C and total N levels of the mine soils will recover rapidly and increase as the time since revegetation increases. The increase in organic C and total N content will have implications for changes in other soil chemical and physical properties. The development of mine soils in wet tropical climate conditions is so far rarely considered only. This study aims to determine changes in the physical and chemical properties of mine soils in the initial stages of formation triggered by the increasing time since revegetation. Soils from permanent observation plots in ex-coal mined sites divided by time since revegetation (0–12 years) were sampled together with an adjacent site with natural forest. Decisive soil physical and chemical properties were determined for the soils from 0 to 30 cm depth. With the increasing time since revegetation, there was a decrease in bulk density, and an increase in total soil porosity following a logarithmic equation. Linear changes with increasing time since revegetation were found for organic C, total N, and available P levels. The linear increase in organic C, total N, and available P levels, the logarithmic decrease in bulk density and the increase in total porosity with increasing time since revegetation suggest that these parameters are controlled by vegetation in the initial stages of mine soil development, while the polynomial changes in extractable P and K (25% HCl), CEC, exchangeable bases, base saturation percentage, and exchangeable Al over time suggest that these parameters can be assigned to processes independent of vegetation and are highly dependent on the composition of the original substrate.