Effects of biochar on Cd uptake and translocation in rice plants under drought conditions

【Objective】Cadmium (Cd) contamination in paddy soils threatens rice safety and human health, and the increasing frequency of drought events under climate change may further influence Cd availability and its uptake by rice plants. This study aims to investigate the effects of biochar on Cd uptake and translocation in rice under drought conditions and to provide a mitigation strategy for the safe production of rice under future extreme climatic conditions.【Method】The experiment was conducted in pots repacked by soil collected from a paddy field and amended with different biochar application rates. During the experiment, we measured soil nutrients, bioavailable Cd concentration, plant growth traits, and Cd uptake and translocation within rice plants.【Result】Amending the soil with biochar moderately increased soil pH and significantly enhanced soil organic matter content, alkaline hydrolyzable nitrogen, available phosphorus, available potassium, and sucrase activity, while reducing the bioavailable Cd content in the soil. The lowest bioavailable Cd concentration was observed when the biochar application rate was 40 t/hm2. Furthermore, biochar application significantly reduced Cd translocation within rice plants.【Conclusion】Among all the treatments, applying 40 t/hm2 biochar under drought conditions was the most effective for reducing Cd uptake and its subsequent translocation in rice plants. Therefore, biochar application can serve as an effective remediation strategy to safeguard rice production in Cd-contaminated paddy fields under drought conditions.