Assessment of biochar filter application in improving chromium stress tolerance and plant physiology in Chinese cabbage (Brassica rapa) under a flow-through water setup

This study is the first to explore the use of biochar as a dynamic filtration medium for Cr remediation in hydroponic systems, demonstrating its dual role in Cr adsorption and physiological stress alleviation. The 2.5 g/L dose was identified as optimal, reducing Cr accumulation in aerial tissues by 62.4% and increasing soluble protein content by 114%. These findings offer a practical and environmentally sustainable solution for managing heavy metal risks in hydroponic and urban agriculture, particularly in resource-limited settings. The proposed technology combines environmental and economic benefits, making it especially suitable for facility-based agricultural production systems.