tomato responded in yielo ta K addilicn:. vu. stash dic noi. In the fartilizaiion with K in the field. a. least a i umpovary depression of Cs-137 uptake was effected. This is congistent with the results of Nishita, et al. (196C), who observed @ Jdacreased absorption of Cs-137 with K fertilization of soil which was low in K. The Rongelap soils are low in K as evidenced by soil analyses and by the very low levels of K in the colder leaves of the plants growing on them. The cifferences between upper and lower foliage in theiz content of the various ions is of special interest. The most usual pattern shows both K and Cs-137 higher in che uppers Leaves than in the lower leaves. Field-colluctec seaevola foliage consistently has higher K bul lowes Cs in the upper than in the iower leaves. This woulc be in accord with 2 previous study (Rediske and Selders, 1952) which showed Cs tc function as = relatively immobilo clement in bean plan's. Deta from additional field samples ef a greater number of plant species is being accumulated at present with the hope of establishing more clearly the differences between species in this respect and the significance of the sharp differences between the older and younger leaves. The K and Cs-137 contentsof field-collected leachates from Rongelap soil have been shown to be greatest immediately