Field study of biochar effects on vegetation and bacterial communities in a restored mine

Mining activities result in the degradation of ecological functions in quarried sites, necessitating remediation after mining ceases. This study evaluated the effects of biochar on ecological restoration, focusing on soil microbial communities and plant growth in a degraded quarry site. A field test compared the impact of biochar on two indigenous plant species (e.g., Castanopsis fissa and Cyclobalanopsis edithiae), and high-throughput sequencing analyzed the soil bacterial community. Results demonstrated that wood biochar significantly enhanced C. fissa growth, increasing plant height by at least 20 % after two years, while C. edithiae exhibited no statistically significant response to biochar amendment, indicating species-dependent effects. Biochar improved soil nutrients, increasing phosphorus and potassium availability. It also enhanced soil bacterial richness by at least 2 % but reduced α-diversity by 7 %, suggesting selective stimulation of beneficial microorganisms. Network analysis revealed increased bacterial network complexity, with nodes and edges rising by 2 % and 28 %, respectively. This strengthens material, information, and energy exchange among microbial communities and might contribute to improved ecosystem functioning. Overall, biochar improved soil nutrients, plant growth, and bacterial richness, demonstrating its potential as a sustainable tool for restoring ecological functions in disturbed sites. These findings highlight the potential of biochar as a sustainable remediation tool for restoring ecological functions in disturbed sites.