UPTAKE OF CESIUM BY GLASSHOUSE VEGETABLE CROPS FROM SOIL AND NUTRIENT SOLUTIONS
Stable cesium (Cs-133) was applied as CsCl to various soils in 10-litre pots in amounts of 0, 0.01, 0.1 and 1 mg Cs per 1 soil. The Cs content of spinach grown on the pots was not affected by the addition of 0.01 and 0.1 mg Cs. The magnitude of the effect of 1 mg Cs per 1 depended on soil texture: this rate resulted in a greater increase in Cs content of spinach on sandy soil than on clay soils.
The uptake of Cs by lettuce, tomato, cucumber and bean from nutrient solutions containing 0, 0.01, 0.1 and 1 mg Cs per 1 was determined. In contrast with uptake from soils, Cs absorption was found to be linearly related to the Cs concentration of the solutions. It was therefore concluded that it is very important to prevent contamination of irrigation water with radioactive cesium. Growers collecting rainwater from glasshouse roofs must stop this practice in periods when fallout may occur.
Certain materials used in glasshouse vegetable production were analysed for cesium. Potassium fertilizers were found to contain a small amount of this element.