Effect of potassium (K) supply on the uptake of 137Cs by spring wheat (Triticum aestivum cv. Tonic): a lysimeter study.

A lysimeter experiment was carried out on a relatively infertile soil to examine the effect of potassium fertiliser application on the uptake of radiocaesium by spring wheat. Porous ceramic cups were used to obtain samples of soil solution. Results showed that the uptake of radiocaesium by spring wheat was reduced by the addition of potassium. However this inhibitory effect was less marked at later stages of plant growth due to factors such as the spatial variability of potassium within the soil, differences in root distribution down the soil profile and age-related demand for potassium by the plant. There was some evidence that a negative power function could be used to describe the relationship between the concentration of 137Cs in the plant and concentrations of potassium or 137Cs:K quotients in soil solution over the whole experimental period. Practical implications of potassium fertilisation in terms of reducing uptake of radiocaesium by crops are discussed.