Cesium-137 in Japanese Soil and Rice Cesium-137 in Japanese Soil and Rice

Japanese soil and rice collected at 15 localities have been analyzed for cesium-137 since 1959 through 1963. The time trend of rice-levels indicates the minimum in 1960 and 1961 and the maximum in 1963, showing more than threefold value of the minimum. A higher dependency was observed of the level of cesium 137 in rice on the fallout rate than either of the cumulative ground deposit or the N-ammonium acetate extractable cesium-137 in soil. Variation with locality is great and the highest rice-level is observed on the northern Japan Sea side, the lowest in the central and southern parts, and intermediate on the northern Pacific side.