Effects of Biochar on the Cd Uptake by Rice and the Cd Fractions in Paddy Soil: A 3-Year Field Experiment

Biochar is a potential amendment for the remediation of Cd-contaminated soils. Although immobilization effect biochar on soil Cd has been studied under indoor laboratory conditions, rice uptake and fractions field conditions still poorly understood. Here, content different organs in were characterized three years after application amounts (0, 7.5, 15, 30 t ha−1, 3 ha−1 year−1). The brown rice, husk, leaf, stem sheath, root treatment could be maximally reduced by up to 26.25%, 20.16%, 20.74%, 33.2%, 26.89%, respectively. altered soil, including decrease exchangeable increase Fe-Mn oxide bound organic Cd. concentration factor was 32% application, while had little influence transfer distribution factor. lasted at least years, but trend efficiency over time different. Risk Assessment Code (RAC) with medium risk level from high level. Redundancy analysis (RDA) revealed that changes pH caused contributed most reduction organs. These findings would enhance our understanding paddy conditions.