ABSTRACT
Selenite and selenate are the major selenium (Se) species in soil that can be efficiently utilized by plants. In contrast, field experiments showed that sulfate facilitated selenate uptake in wheat and buckwheat. Irrespective of the species of Se fertilizers, sulfur (S) application significantly inhibited the Se uptake, and there was no significant difference in the inhibitory effect between elemental S and sulfate. For selenate-treated plants, the two S fertilizers caused a consistent reduction in the Se concentration of seeds. In contrast, with the selenate treatment, sulfate significantly reduced the Se concentrations in shoots. Selenium fractions and species in soil are more relevant to Se uptake and accumulation in crops than the total Se in soil. Soluble and exchangeable Se in soil making up approximately 10–15% of the total Se. Application of S and Se fertilizers significantly caused antagonisms between Se and S and inhibited the uptake of Se by roots, and also decreased the availability of Se in soil.
