Organic carbon-based amendments effectively reclaim post-tin mining site via modified soil organic carbon characteristics

The complex process of post-mining land reclamation poses a great challenge in combatting land degradation and food insecurity. In this study, a field experiment was conducted to determine the effects of different soil amendments on soil organic carbon (SOC) characteristics and plant biomass to reclaim a highly degraded soil after tin-mining.

Quantity and quality of SOC, annual plant biomass, and their relationships were determined over four years in post-tin mining soil that had been treated with six different soil amendments: control, dolomite, compost, charcoal, charcoal with compost and charcoal with sawdust.

Charcoal-compost application led to the highest increase in SOC stocks, followed by compost application. It enhanced annual plant biomass to twice that of the control treatment. In contrast to organic soil amendments, dolomite tended to cause SOC stock losses over time. Dissolved organic carbon exhibited a highly dynamic pattern, with a tendency to decrease over time. Dolomite and charcoal application induced SOC chemical composition changes distinct from other treatments. The potential interactions between amendment materials and time as well as crop species were observed for SOC characterization.

Charcoal-compost combination with regular compost application was recommended to reclaim the soil for promoting SOC accumulation whilst sustaining crop production.