Abstract:
Biochar has emerged as an organic and environmentally safe solution for nutrient deficit and metal contaminated soils. A one month pot experiment was conducted using metal (Lead and Cadmium) spiked soil, treated with 1% (BC 1) and 5% (BC5) Cannabis sativa derived biochar amendments independently, to assess the impacts of biochar addition on soil nutrient content and heavy metal immobilization. Cannabis sativa biochar was characterized by physicochemical, proximate and instrumental analysis which revealed the biochar to be brittle, porous and of an alkaline and labile nature. Soil chemical parameters and heavy metals (lead and cadmium) were determined in the beginning and after ten day interval of experimental period. Both biochar amendments increased the pH and electrical conductivity (EC) of the soil as compared to the control with BC 1 being more effective. Oxidizable organic carbon (OC), total organic carbon (TOC) and organic matter (OM) were successfully increased by both biochar treatments with BC5 showing more prominent increments than BC 1. In case of BC5, OC increased by 189.86%, TOC increased by 189.13% and OM increased by 188.68% as compared to the control. Soil available phosphorous (SAP) and soil available nitrogen (SAN) were also enhanced by the biochar additions with BC5 presenting more pronounced improvements than BC I. SAN and SAP improved by 233.3% and 101.79% respectively for BC5 as compared to the control. Both lead (Pb) and cadmium (Cd) were effectively stabilized by the biochar amendments. BC 1 remained more successful though, achieving a reduction of lead and cadmium concentrations by 45.74% and 56.58% respectively in comparison to the control. Based on the results of current study, it can be concluded that biochar addition successfully improved the soil nutrient content and effectively addressed the problem of heavy metal contamination with 1% biochar addition being more feasible for heavy metal immobilization and 5% biochar addition being more favourable for improving the soil nutrient and carbon pool.
