Endemic microbes and biochar technology increased above-ground biomass and carbon stock of Pterocarpus indicus Willd. in a mined-out area

This study aimed to develop a technology to bring mined-out areas back to life and thereby contribute to shaping priority areas towards sustainable development and energy security of the country. In this study, growth and development, above-ground biomass, and carbon stocking of Pterocarpus indicus were investigated 24 months after field planting on mine tailings. Five months prior to outplanting, the nursery-grown seedlings were treated with the UPLB-BIOTECH developed inoculants such as the MYKOVAM®, MYKORICH® and BioNTM and the newly developed inoculants containing endemic isolates of arbuscular mycorrhizal fungi (NewMyc) and nitrogen fixing bacteria (NewNFB); applied singly or in combination, and either amended or not with biochar from bamboo (BB) wastes. Except for BioN- and NewMyc-treated plants, amendment of biochar in treated P. indicus resulted in significantly higher growth increment, basal area, biomass density (Mg ha-1), and carbon dioxide sequestered (Mg ha-1). Overall, NFB+NewMyc+BB promoted the highest growth increment, basal area, biomass density, and carbon stock. Amendment of BB in NFB+NewMyc increased the biomass density by 210.33% (from 5.37 Mg ha-1 to 16.66 Mg ha-1) and the carbon stock by 79.34% (from 8.86 Mg ha-1 to 15.89 Mg ha-1) relative to the control. Meanwhile, its counterpart without BB was just 13.4% higher in biomass and carbon stock relative to the control. With BB alone, plant biomass and carbon stock were just 12% higher relative to the control. This implied a better growth performance of P. indicus with biofertilizers containing endemic AMF and NFB than with BioN, MYKOVAM, MYKORICH, or NFB alone. Results show the value of these new inoculants in developing biofertilizers for an integrated bioremediation protocol for mined-out sites in the country and other countries with similar ecosystems. Further, the findings can support a relevant policy for the adoption, resourcing and dissemination of the technology and/or protocol. Finally, the technology/protocol contributes to the country’s efforts in developing a sustainable economy.