Abstract: China is short of soil resources for arable lands. There is a significant overlap between heavy metal soil pollution in arable lands and the primary grain-producing regions, which seriously affects the quality of agricultural products, threatens human health and ecological safety, and becomes challenges for the remediation of polluted cropland soils. The applications of silicon fertilizer could supplement plant nutrition and mitigate the toxic effects of heavy metals. Nano-silicon fertilizer has received great attention due to its advantages of large specific surface area, multiple micro-pores, high utilization efficiency, strong adsorption capacity for pollutants, and enhancement of plant resistance. These advantages demonstrate great potential for the remediation of polluted croplands. In this review, we explored the differences in physical and chemical properties between various types of silicon fertilizers (traditional silicon fertilizers and nano-silicon fertilizers), the action mechanisms of different types of silicon fertilizers on the bioavailability of heavy metals in soil, the absorption and translocation of heavy metals in crops, and the physiological regulation mechanisms of alleviating heavy metal toxicity. The utilization of nanosilicon fertilizer exhibits promising prospects in the remediation of heavy metal pollution in croplands. The current research challenges include the optimal dose and size of nano-silicon fertilizer for agricultural applications, and the molecular mechanism by which nano-silicon fertilizer alleviates heavy metal toxicity. These issues need to be solved in the future to advance the effective utilization of nano-fertilizers in addressing agricultural pollution and promoting sustainable green development, thereby ensuring optimal soil health and food security.

Key words: nano-silicon, heavy metal, soil remediation, physiological regulation