Plant availability of arsenic and cadmium as influenced by biochar application to soil

摘要

Biochar has gained significant importance due to its ability to increase long-term soil carbon pool and crop productivity. A pot experiment was conducted to investigate the influence of biochar on the availability of arsenic (As) and cadmium (Cd) to maize. An activated wood biochar was applied at three rates (0, 5 and 15 g/kg) in factorial combinations with three rates (0,10 and 50 mg/kg) each of As and Cd separately to a sandy soil. After 10 weeks of growth, crop was harvested and dry matter yield and concentration of As and Cd were determined. The soil was analysed for extractable trace elements after the plant harvest. The results showed that the addition of wood biochar to soil did not have any significant influence on the dry matter yield of maize shoot, even at the highest application rate. However, application of As and Cd significantly reduced the dry matter yield by 93 and 27%, respectively. Biochar application decreased the concentration of both As and Cd in maize shoots. However, the concentrations of extractable As increased with biochar treatment and the effect of biochar on DTPA extractable Cd in soil was inconsistent. The results show that biochar application can significantly reduce the bioavailability of As and Cd to plants and suggest that biochar application may have potential for remediating contaminated soils.