Biochar Amendment for the Mitigation of Heavy Metals Accumulation in Corn (Zea mays L.) Plants Grown in Acidic Soils

Biological methods including the use of biochar may favorably alleviate heavy metals accumulation in crop plants including corn (Zea mays L.). The effects of biochar (BT) (rice straw and date palm) application on the mitigation of heavy metals uptake including lead (Pb), cadmium (Cd), copper (Cu) and zinc (Zn) by corn (Zea mays L.) plants were investigated. The biochars were produced by pyrolizing rice straw at 500 degrees C (30 min) and date palm at 400oC (one hour). Different experimental stages were conducted including: (1) contaminating experimental soil with the standard level (H1) of Cd, Pb, Zn and Cu at 1, 50, 50 and 100 mgkg- 1, respectively and twice the standard level (H2), and incubating the soil at 30oC for 30 days, and (2) growing corn plants in the greenhouse using the contaminated soils treated with rice and palm biochar at 0 (BP1), 4 (BP2) and 8% (BP3). The H treatment significantly affected corn uptake of Cu and Zn. The BT and H interactions were also significant on corn Pb, Cd and Zn, and BP*H interaction also significantly affected corn Zn content. The highest reduction was resulted by palm biochar at BP3. Plant Cd concentration (in H2) significantly decreased in all biochar treatments with the highest in palm BP3 and the lowest in rice BP2. In both H1 and H2, biochar significantly (p < 0.01) decreased plant Cu concentration. The tested biochars can be favorably used for mitigating the accumulation of heavy metals in corn in acidic contaminated soils.