Abstract
Since Japan is a mountainous country, the arable land covers only 16per cent of the whole area. Plains are cultivated as far as possible, and even considerably steep mountainous districts are also put under the plough. 12per cent of the whole upland field and 8per cent of the whole paddy-field in this country are situated on steep slopes of more than 15 degrees. Moreover, draining of lakes and the shallow sea beds is being carried on. It seems, therefore, there is hardly any more room to be brought under cultivation.
1. The paddy-field, which now covers 56per cent of Japan's cultivated land, has been the most essential land utilization type since the prehistoric age. Irrigation facilities are indispensable for ploughing a rice-field. And, Japanese farmers have taken the utmost pains to carry out irrigation works through periods. There are two ways in which a paddy-field can be enlarged in time to come. One is to improve the variety of rice-plant and growing technics in order to enable farmers to enlarge a paddy-field in districts of low temperature, chiefly in Hokkaido District. The other way is to work out irrigation facilities on a large scale so that a rice-field can be tilled on an eminence or on the slanting surface of a volcano which has never been utilized as a rice-field.
2. The upland-field, which is the secondary type of land utilization in this country, has been so far cultivated in the districts where a paddy-field is unable to be tilled. From times past, farmers generally cropt a field with crops for self-supporting. Since the middle of the 19th Century, however, such an upland-field has been increased as can be cropt with fruits, vegetables, tea-shrubs, mulberry-trees and other industrial crops; and it is showing a high productivity.
