Inhibition Effects of Foliar Spraying of Nano-Si Fertilizer on Cd Accumulation of Two Pepper Varieties

Nano silicon (Nano-Si) fertilizer can inhibit the absorption and accumulation of heavy metals by crops, but its effects on varieties with different accumulation capacity of heavy metals were rarely studied. In this study, a field plot experiment was conducted in a cadmium (Cd) contaminated greenhouse to study the effects of foliar spraying nano-Si fertilizer on the yield of single plant, Cd concentration in various parts of plants, and fruit nutritional quality of both the variety with low accumulation capacity (JY) and the variety with high accumulation capacity (GJ). The results show that foliar spraying nano-Si fertilizer significantly increased the yield of fruits. And in CK treatments, an obvious difference in Cd concentration in various parts of plants was observed between the two varieties, among which fruit Cd concentration of JY was 44.7%, lower than that of GJ. Foliar spraying of nano-Si fertilizer significantly reduced Cd concentration of the edible part, leading to a lower Cd concentration of JY fruit than the limit value of the National Food Safety Standard (GB 2762-2022). Further analysis reveals that foliar spraying Nano-Si fertilizer significantly increased soluble protein and soluble sugar concentration of fruits. These results indicate that foliar nano-Si fertilizer could not only help to achieve safety production of the polluted greenhouse when combined with low Cd accumulation plant variety, but also improve the nutritional quality and yield of pepper.