The Transformative Effects of Coconut Shell Biochar on Heavy Metal Bioavailability in Soil, Phytotoxicity and Yield in French Bean

In a controlled pot experiment using a Completely Randomized Design (CRD) conducted at UAS, GKVK, Bangalore, India, soil was artificially contaminated with different concentrations of four types of heavy metals (Cd, Cr, Pb and As). French Bean (Phaseolus vulgaris L.) crop was grown to assess the remediation caused by varying levels of coconut shell biochar. It was found that the biochar was capable of causing a reduction ranging from 68.1- 90.1 per cent in the bioavailability of heavy metals with reductions peaking at 5% application (e.g., 87.5–90.1% for Pb). Soil health parameters (pH, nutrient status, microbial activity) also improved with maximum yield improvement at 5 per cent application rate. Phytotoxic symptoms were not observed in the plants.