Preliminary Findings on Cadmium Bioaccumulation and Photosynthesis in Rice (Oryza sativa L.) and Maize (Zea mays L.)...

Understanding the structural differences between feedstocks is critical for biochar effectiveness in plant growth. To examine the efficiency of biochars with unique physiological structures in a cadmium (Cd)-polluted soil, rice and maize as C3 and C4 plants, as well as biochar generated from their residues, defined as BC3 and BC4, were utilized. The experiment involved a control and a Cd-polluted soil (20 mg kg^-1) without biochar application, and applications of each type of biochar (20 t ha^-1) on Cd-polluted or unpolluted soil. In rice and maize fields, BC3 application led to the highest value of cation exchange capacity (CEC), with increases of 162% and 115%, respectively, over the control, while CEC increased by 110% and 71% with BC4 in the rice and maize field, respectively. As compared to the control, BC3 and BC4 dramatically enhanced the photosynthetic rate (Pn) of rice by 116% and 80%, respectively, and maize by 67% and 31%. BC3 and BC4 significantly decreased the Cd transfer coefficient in rice by 54% and 30% and in maize by 45% and 21%. Overall, BC3 is preferred over BC4 for establishing rice and maize in Cd-polluted soil, as it has a lower C/N ratio, a considerably higher surface area, and more notable alkaline features such as a higher CEC and nutrient storage.