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The effect of different N rates on Cd speciation of Cd-contaminated soil with oilseed rape
- Fan, Shiqi, Zhang, Yulong
- Journal of plant nutrition 2017 v.40 no.19 pp. 2680-2690
- Brassica napus, bioavailability, cadmium, correlation, polluted soils, soil pH
- The aim of the study is to explore the effects of Nitrogen (N) rates on the speciation of Cadmium (Cd) in soil with oilseed rape (Brassica napus L.). A pot experiment was conducted at N1 (0 g/kg), N2 (0.125 g/kg), N3 (0.25 g/kg) and N4 (0.375 g/kg) rates. Correlation between Cd speciation and bioavailability, soil pH were analyzed. Cd speciation was significantly affected by N rates. Exchangeable Cd (EXC-Cd) and carbonate Cd (CAR-Cd) in soil showed a contrary pattern with residual Cd (RES-Cd) and organic Cd (ORG-Cd), respectively. Correlation analysis demonstrated EXC-Cd and CAR-Cd positively correlated with Cd bioavailability but negatively correlated with soil pH at later phase of oilseed rape (p < 0.05). Cd bioavailability could be promoted by increasing the EXC-Cd and CAR-Cd concentration at the expense of RES-Cd. Our results suggest that N rates may affect Cd speciation in regulation of soil pH, thus further affect Cd bioavailability.