On the bad harvest type of rice in japan

Abstract

In this report, the auther considered the regional characters of the bad harvest on rice from the same data—“table 1” and “figure 1”—in the former report that analysed the successive statistics from sixty to seventy one years of all the forty six prefectures in Japan with the statistical definition of bad harvest suggested by the anther. The results are as follows. Considering the regional appearance of the bad harvest years from figure 1, it should be classified into the three types as shown in table 1 of this report. The characteristics of each three type is summarized as follows. I. North type. This type is composed the Hokkaido prefecture only and has the most severe bad harvest. Its trans-mode percent is the maximum, 15.9%, in Japan as in table 14). II. North-east type. The eighteen prefectures locate in the eastern north part from about middle of the mainland in Japan belongs to this type and has next severe bad harvest. The characteristic of this type is the width of about seventeen years period of bad harvest and the length of about thirty years, cyclic period. The pacific coastal four prefectures in the North-east district of this type has comparatively high trans-mode percent. III. South-west type. The twenty seven prefectures except the two types described above, locate in the western south part of Japan belongs to this type. It has probably a longer cyclic period than the former type, but is difficult to infer it stochastically for the sake of the short statistical period of sixty years length. This type is slighter bad harvest than the formers, but appears more frequently. From the view point of whole Japan, the bad harvest appears thirty times in the space of this sixty years at any sib prefectures of Japan. As a result of considering the correllative relationship between these three types, the six appearing types of bad harvest obtained as follows; the single appear of each three type, the double appear of I and II or I and III types and the triple appear of all the three types in the same year as shown in figure 1 and table 2. The most lowering injury to the rice production of Japan is the case of triple appear type, the average Ic is 79.3%. The next is that of double appear type, the average Ic is 92.3%. The single appearance of each three type is slighter decrease than former, the average Ic is 99.3%. On the relation between the each three type and the average Ic of Japan, the north type is the largest decrease, the N-E type next and the S-W type slightest. © 1951, The Society of Agricultural Meteorology of Japan. All rights reserved.