Fertilization is a crucial agrological measure for agricultural production that can significantly impact the removal of Cd from irrigation water by paddy crusts (PC). In this study, laboratory and field experiments were conducted to investigate the impact of fertilization at low, medium, and high concentrations on the accumulation of Cadmium (Cd) in PC and the underlying mechanisms involved. The results showed that only low fertilizer concentration could promote the removal of Cd by PC, which reduced the Cd concentration in irrigation water from 19.52 μg/L to 5.35 μg/L. Conversely, medium and high fertilizer concentrations reduced the accumulation of Cd by PC. After fertilizer addition, the proportion of Fe-Mn oxidizable-Cd in PC reached 55 % (with low concentration of fertilizer treatment). The application of low concentration of fertilizer was found to stimulate the growth of filamentous green algae, leading to a significant increase in the relative abundance of sphingomonadaceae (by 1.39 %) and comamonadaceae (by 1.29 %). The XRD, SEM and correlation analysis show that a large amount of manganese oxide is formed on the surface of PC, which increases the fixation of Cd. These findings provide a new perspective for the remediation of heavy metal contamination in paddy fields.

施肥是农业生产的一项重要农业措施，可显着影响稻壳 (PC) 从灌溉水中去除镉的效果。本研究通过实验室和田间实验来研究低、中、高浓度施肥对 PC 中镉 (Cd) 积累的影响及其潜在机制。结果表明，低施肥浓度即可促进PC对Cd的去除，使灌溉水中Cd浓度从19.52 μg/L降低至5.35 μg/L。相反，中、高肥料浓度则减少了PC对Cd的积累。添加肥料后，PC中Fe-Mn可氧化-Cd的比例达到55%（低浓度肥料处理）。研究发现，低浓度肥料的施用可以刺激丝状绿藻的生长，导致鞘氨醇单胞菌科（增加1.39％）和丛毛单胞菌科（增加1.29％）的相对丰度显着增加。XRD、SEM及相关分析表明PC表面形成了大量的氧化锰，增加了Cd的固定。这些研究结果为稻田重金属污染的修复提供了新的视角。