EFFECT OF NITROGEN ON CESIUM-137 IN SOILS AND ITS UPTAKE BY OAT PLANTS

In an experiment designed to show the effects of time of addition of NH4 relative to Cs-137 and of NH, compared with NO3, the results showed conclusively that NH4 caused higher Cs-137 concentrations in oats than did the NO3 form of N at low soil K contents. The results were less conclusive for soils to which K had been applied. When NH4 was applied before Cs-137, in most instances the Cs-137 concentration was higher than when Cs was applied before NH4 without added K. When K was added, however, the trends were for the most part the reverse. Thus NH4, K and Cs-137 in the soil interact for sites on the soil exchange complex and the amount of Cs-137 taken up by the plant is a function of this interaction.Liming of one acid soil consistently increased the Cs-137 concentration and uptake, whereas in another acid soil the effects of liming were less consistent.