Alleviating Cd translocation and accumulation in soil‐rice systems: Combination of foliar spraying of nano‐Si or nano‐Se and soil application of nano‐humus

Cadmium (Cd) contamination in farmland is extensive in China. Thus, exploring a cost‐effective and practical approach to control Cd contamination and ensure the sustainable use of soil is essential. Agronomic management practices, such as foliar spraying of nano‐silicon (nano‐Si) or nano‐selenium (nano‐Se), and soil amendments are very effective in soil contamination control and ensuring agricultural security. In this study, foliar application of nano‐Si (or Se) and soil application of nano‐humus were combined and applied to Cd‐contaminated soil (1.9 mg kg‐¹) sown with rice. The application of nano‐humus in soil mainly reduced the proportion of oxidizable Cd and inhibited Cd migration from soil to rice. Cd translocation to the grain in rice was prevented by foliar application of nano‐Si or nano‐Se. Importantly, foliar application of 0.025 mM nano‐Se decreased Cd in rice grain to around 72% of that in the control, leading to a Cd content lower than the Cd standard limit in rice (0.2 mg kg‐¹). These findings indicate that foliar spraying and soil treatment can improve the tolerance of rice to Cd and prevent Cd migration into the grain.