Abstract: To explore the effects of silicon fertilizer (Si) and water-soluble chitosan (WSC) on the cadmium (Cd) content of rapeseed, a field experiment was set up in a cropland with a slight-moderate level of Cd pollution, around a typical operating smelter in Jiyuan City, Henan Province. We examined the effects of Si and WSC foliar fertilizations on biomass, Cd content, and bioconcentration coefficient of two large-scale planting cultivars of winter rapeseed (Brassica napus), Qinyou No. 1 (QY₁) and Sanyuehuang (SYH). The results showed that, compared with the control, spraying Si or WSC could reduce the Cd uptake by the grains and husks of the two tested rapeseeds. After foliar spraying of Si and WSC, the Cd content in QY₁ grains decreased by 8.80%-44.01% and 15.01%-37.77%, respectively; the Cd content in SYH grains decreased by 20.94%-32.42% and 14.33%-28.65%, respectively. The Cd contents of grains and husks of rapeseed reached the lowest level after spraying Si twice, and second lowest was the treatment with spraying WSC once. Compared with SYH, QY₁ had a higher biomass and lower Cd enrichment capacity after foliar fertilizations. Therefore, QY₁ is more suitable for the safe production in slightly to moderately Cd-contaminated soil. In conclusion, the low-Cd-accumulating rapeseed cultivar combined with agronomic measures of spraying foliar fertilizer can preliminarily realize the safe utilization of slightly or moderately Cd-contaminated soils surrounding the smelter.

Key words: winter rapeseed, cadmium, foliar fertilization, farmland, safe utilization.