Effects of sulfate on cadmium uptake in wheat grown in paddy soil - pot experiment

Rice-wheat rotation is common in China. Cadmium (Cd) and sulfur (S) are added to rice fields through various activities. The sulfur amendment has been recommended to control the uptake of Cd in rice. However, the effect of S on Cd uptake in winter wheat cultivated in paddy soil is rarely reported. A greenhouse pot experiment including two Cd levels (0, 10 mg Cd/kg, as CdCl2) combined with three S rates (0, 30, 60 mg S/kg, as Na2SO4) was performed to investigate the effect of S application on uptake and allocation of Cd in wheat cultivated in paddy soil. Cadmium concentrations in wheat grain significantly (P < 0.05) increased by 37% at 30 mg S/kg, and the percentage of Cd allocation to grain significantly (P < 0.05) increased by 7% at 60 mg S/kg compared with non-S addition treatment when wheat was grown in Cd-added soil. For the low Cd soil, a similar trend was seen, but Cd increases were insignificant for grain while significant (P < 0.05) for root at 60 mg S/kg. In conclusion, S fertiliser may promote Cd accumulation in wheat grain and should be considered when it is used for wheat in paddy soils.