Effect of wheat straw derived biochar on the bioavailability of Pb, Cd and Cr using maize as test crop

Abstract

A pot experiment was conducted in the greenhouse to assess the effect of wheat straw derived biochar on the bioavailability of Pb, Cd and Cr using maize as test crop. Surface (0–20 cm) soil collected from the research farm of The University of Agriculture Peshawar was amended with 0, 2, 4 and 6% biochar respectively. Ten kg soil was placed in pots and all pots were spiked with Pb, Cd and Cr at concentrations 0, 5, 10 and 50 mg kg−1 of each element. The experiment was conducted in a completely randomized design, replicated three times. Maize seeds were sown in pots in wetter conditions. Soil and plant samples were taken at harvest time. Results show that soil Pb, Cd and Cr reduced from 15.5, 5.38 and 5.85 mg kg−1 in control to 1.34, 0.69 and 0.75 mg kg−1 respectively with application of 6% biochar when values were averaged over the contamination levels. Similarly, Pb, Cd and Cr accumulation in plant were reduced by the application of biochar as compared to control. As compared to control, there was a significant improvement in the plant growth with biochar at elevated levels of Pb, Cd and Cr in soil. Overall, the application of wheat straw biochar might be effective in immobilization of metal in the soil and reducing its uptake to plant. However, investigation of the residual effect of biochar is required for sustainable use of biochar for remediation of contaminated soil.

Keywords

• Biochar
• Heavy metals
• Bio-availability
• Maize growth