Biochar's ability to trap Cadmium (Cd) in soil changes over time. Three types of biochar were tested in soil during wheat planting. The biochar's ash and anion levels decreased while oxygen groups and CEC increased with time. This led to reduced Cd content on biochar, especially a 68.9% drop in WBC300. However, unstable Cd forms on biochar increased (from 3% to 17% for WBC300), which made biochar less effective at stopping Cd buildup in wheat. As biochar ages in soil, its direct Cd trapping ability weakens. The way Cd sticks to biochar alters from settling to forming complexes, which impacts its function in soil cleansing.