Abstract:
The objective was to explore the mechanism of reducing cadmium (Cd) toxicity of agricultural products by combining soil amendments with foliar selenium (Se) fertilizer. Incubation experiment was carried out to study the optimal treatment of available Cd passivation in soil with different amounts of cow manure (7.5 and 15 g kg
−1) and lime (1, 2, 3, 4 and 5 g kg
−1), and pot experiment was carried out to study the effects of combined application of amendments and foliar Se fertilizer (1, 2, 4 and 8 mg L
−1) on Cd uptake by pakchoi in different Cd contaminated soils (0.5, 3 and 6 mg kg
−1). The results showed that: (1) compared with the control treatment, the application of 7.5 g kg
−1 cow manure combined with 5 g kg
−1 lime had the most significant passivation effect on soil Cd, and the available Cd content decreased by 37.9%. (2) Compared with the single application of amendments, foliar Se application combined with the amendments significantly inhibited Cd uptake by pakchoi. Spraying 4 mg L
−1 Se fertilizer to pakchoi leaves in mildly and moderately contaminated soil (0.5 and 3 mg kg
−1 Cd) decreased Cd uptakes by 12.9% and 78.7%, and the malonaldehyde contents by 29.9% and 60.6%, respectively. The Cd and malonaldehyde contents of pakchoi were decreased by 81.4% and 71.9%, respectively, by spraying 8 mg L
−1 Se in heavily polluted soil (6 mg kg
−1 Cd). The activities of antioxidant enzymes and glutathione content of pakchoi were increased after spraying foliar Se fertilizer.