Abstract
1. The author caluclated long-term yield standards of paddy rice, upland rice, barley, wheat, soybean, and azuki bean in Aomori, Iwate, Akita, Miyagi, Yamagata, Fukushima, Niigata, Tochigi, kyoto and Wakayama Prefectural Agricultural Experiment Stations, considering these values as the indices of soil productivity for these crops. 2. He discussed, depending on these data the problem of the under-estimation of crop yields by the Official Agricultural Statistics. 3. The variation curves of the actual yield of these individual crop were examined. 4. He made a σ-analysis of the yield in these individual crops, and discussed the contributions of the variety factors, the year factors and the locality factors in defining the yield of the crop.
