1. Vegetation is a phenomenon which reflects many conditions of environment as functional space.
We can regard crops as the artificial vegetation which reflects human conditions as well as natural conditionons. In other words, we can recognize the environment of agricultural communities by the crops.
2. The qualitative close relation between regional conditions and varieties of aquatic-rice was proved by D. Matsuo in Omi-district. Then the auther attempted somewhat quantitative analysis in Miyagi and Aichi prefectures by the variety of aquatic-rice.
The measuring unit is sub-prefecture (Gun).
In Aichi-prefecture we divided it into 5 regions having the different percentages of the varieties. Fig. 1 and Table 2 show the properties and the transition of regional environment respectively.
In Miyagi-prefecture the regional percentage of the varieties having the same quality are tested by Smirnov's relent-test method, every year as samples of environmental requisition from regional “population.” The requisitions are classified as follow: 1) Resistance to coolness 2) Resistance to rice-blast, other diseases and harmful-worms etc. 3) Requirement for better harvest 4) Requirement for better quality, for food. Since Gun is an administrative unit, we have to divert it into the boundary under the actual landutilization. The auther has done this by free-hand drawing and got Fig. 2, according to calculation in Table 3.
4. On making the e attempts the anther had made up Fig. 4, to glimps the distribution of natural and economic environments for growing rice, though many restrictions exist. These data are given in by Agricultural Experiment Station of Japan.
In detail this map is only forcast.
a) Resistance to coolness is required in Hokkaido and the north-eastern part of Tohoku district. In these regions staple food are not rice.
b) Resistance to Rice-blast etc. are mainly required in mountainland because in these districts the techniques of rice production are poorer. It is very often that we find old customs existing in these regions.
c) Economic conditions as require good harvest and good quality for food appear in the regions which is free from natural control.
The western coast of Tohoku district shows clear contrast to its eastern part. From the Nobi Plain to the coast of wester part of Setouchi, as climate and soil are in the best condition for aquatic-rice, and economic conditions are also very good, so the better quality for food is required and a large number of varieties are found in these areas.
d) resistance to drought and brine is found in the western part of Japan, except for the Kujukuri Coastal-Plain. These regions are also poor in irrigation-technics. On the contraly resistance to dampness and flood is required along the rivers in the eastern part of Japan.
e) The techniques of rice-culture in the southern islands of Kyushu are different from those in main lands. Like Loochoo they seed and gather in rice as early as they can to avoid the damages from Typhoon and harmfulworms. Used is Rikuu No. 132, are presentative variety in Tohoku district.
