Effect of Rice Residue Biochar on Lead Remediation, Growth, and Micronutrient Uptake in Indian Mustard (Brassica juncea (L.) Czern.) Cultivated in Contaminated Soil.

A pot experiment at Punjab Agricultural University, Ludhiana, India, assessed rice residue biochar's effect on remediating lead and cadmium in soil and on Indian mustard growth. Soil spiked with Cd (0, 10, 25 mg kg⁻¹) and Pb (0, 25, 50 mg kg⁻¹) was amended with biochar (0, 0.5, 1, 2% w/w) in a completely randomized design with three replications. Adding 2% biochar reduced DTPA-Pb in soil and Pb in shoots by 61% and 56%, respectively. Biochar increased dry matter yield (DMY) by 18% at 1% but decreased by 19% at 2%. The 1% biochar increased shoot Fe, Mn, Zn, and Cu by 11.39%, 26.74%, 5.89%, and 17.72%, respectively. Rice residue biochar significantly improved the DMY and micronutrient content of Indian mustard by reducing lead contamination in co-contaminated soil.