1959 年 32 巻 2 号 p. 70-82
For many years, the water of Lake Biwa has been used to irrigate the plain near by. Simple instruments such as well-sweeps or tread-mills were used before, but now motor is widely installed for that purpose. The area irrigated stretches to more than 9, 500 cho in Shiga Prefecture, and the plain, to the east of Lake Piwa forms its center. The remarkable characteristics of the irrigation system may be summarized as follows:
(1) In most places, water is drawn in one step directly into the field from the lake or through some water-channel, the height of the water to be pumped up in such a case being about two meters. According to the height of the land or the water situation, however, water must be pumped up at two, three or four levels.
(2) The pumping facilities sometimes belong to a farmer individually, or when they are on a large scale they are operated under the control of several towns or villages. Some irrigationmachines are carried from farm to farm by boat, and others are fixed on the rice-field.
(3) The height and the width of the land which may be irrigated are gradually increasing according to the improved pumping techniques.
(4) Since the introduction of motor for the purpose of irrigation, the intensive farming has been greatly promoted, and the mode of irrigation has been greatly improved.