1. Ôcho Village, located on Osaki-shimo Island in the inland sea of Setouchi, is known as a village most specialized in citrus culture in Japan. The ratio of orchards to the total arable land was 97% in 1929. During the war, 20% of the fruit trees were cut down. And by 1950, the ratio had again increased up to 90%. Before the springing up of citrus culture in the village, villagers were growing peaches. In 1859, UNSHU tangerine was introduced to the village. Early-crop (Wase) UNSHU tangerine was introduced in 1903, which at present. occupies 55% of the total amount of citrus crop in Ôchô. This is of the highest as the rate of early-crop UNSHU in Japan.
2. The area of Ôchô Village covers a sloping land of 10 to 40 degrees. Thecitrus trees are planted in terraced fields, 70% of which have stone-steps and. 30% soil-steps. To carry the fruits down the steep slope, a simple cableway was set up in 1921. Today, there are 46 cablecars, in the village, by which 30% of the total crop of tangerines are carried down the slope. The entire cable system is operated by electricity and under the management of the cooperative of the villagers. There is no comparable example to this scheme in Japan.
3. Canned tangerine was first made here in Japan in 1927. The markets for Ôchô tangerines are Kôbe-Osaka area (40%), Tôkyo (30%), and others. Marketing of the early-crop UNSHU is made in October, 35%; November, 50%; December, 15%. The ordinary UNSHU is shipped in November, 10% December, 30%; January, 15%; February 20% ; March, 20%; April, 5%.
4. One of the characteristics of citrus culture in Ôchô is the “watarisaku” (farming over the water). Out of 700 cho (1 cho _??_ 1 ha.) of citrus orchard belonging to the villagers, 300 ch5 is located within the village and 400 cho is scatteringly distributed in 30 other villages, namely in many other neighbouring islands. They maintain their “farming over the water” by 200 nonpowered boats and 350 powered boats. The followings are considered to be the factors in bringing up an unusual manner of farming as this.
(1) Limited area of land and increasing population. (2) The sea is calm even in winter, so ferrying by small boats to the orchards in other islands is made without danger. (3) The village of Ôchô embraces a good natural harbour, which enables several hundred boats to be at anchor at one time. And as the harbour faces to the east, it is shielded from the north-west winter monsoon. (4) As the land is limited in area, its price is high. If one sells 1 tan (1/10 cho) of upland fields in Ôchô, he will be able to purchase 5 tan of uplandfields or even more of forest in Ehime Prefecture. (5) There are customs of establishing “branch families” and of “inheritance by the youngest child” in Ôchô. The eldest son and the younger ones, got mnarried, buy orchards outside the village, and settle there. The younger children stay in their native house and engage in fruit-growing, instead of becoming fantory workers as is usually the case in other farm areas. (9) They traditionally have skilled techniques in fruit-growing. The general standard of techniques has been high. The villagers are industrious and have no political disputes. The present village master is the third one since 1889. (7) The successive, village masters encouraged the farming over the water. The Hiroshima Agriculture and Industry Bank had actively assisted the farmers in purchasing farmland, loaning to them over one million yen since the end of the Meiji, era. Due to the recent inflation, all the loan has been returned, and thevillage is prosperous. (8) Citrus growing has the highest possibility of cash income. Industrial processing of the products is developing, and the enterprise, is economically stable.

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Innamino upland has the highest density of irrigation reservoirs for paddyfields in Japan. As the upland is made up of sand and gravel beds, water for drinking and irrigation was difficult to be obtained. So it was almost impossible to cultivate the land in ancient time. In the prehistoric age, paddy fields were opened only in a small area near the springs at the foot of the marginal cliffs of the upland. In the Nara period, reservoir irrigation was begun by damming up some of the shallow ravines in the upland. But as the relative height of the upland is large, it was difficult to lead the water from rivers. up to the surface of the upland. At the end of the middle age, when engin eering techinique developed in connection with fortification, the technique was possibly applied to the irrigation work, and there came a new epoch in the reclamation of the upland. At first, the river course of the Kako River was improved and its delta plain was reclaimed. Then it was successfully carried out to lead the water from. the Kako River and its tributaries and the Akashi River up into the reservoirs. constructed on the upland. Thus the upland surface was rather rapidly reclaimed. But as the time-period for supplying river water into reservoirs was ordinarily limited, irrigation water for the newly reclaimed paddy fields on the upland could not be sufficient, so the quarrel for water constantly occurred. At present, a new method of welldrilling irrigation has been applied, while the improvement of irrigation canals and reservoirs has been also promoted. The development of new paddyfields which had been so eagerly promoted in the years of the feudal-clan government, was irresistively ceased in the Meiji era. And, thereafter, conversion of upland fields into paddy-fields was made. Nowadays, the rice-and-ccorn agriculture has become intensive intending to meet the demands of a big city to which the surrouding agricultural villages are being centralized.

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Oyachi, situated in the northeastern corner of the Yonezawa Basin (Fig. 1), is a kind of bog lake with an area of 1020 ha, 950 ha of which is used as rice fields and the rest, 70 ha, is left as marsh. The rice fields here are classified into the two, the “Yachita” (marshy paddy fields) and the “Ukita” (floating paddy fields), the area is 700 ha. and 250 ha. respectively. The Yachita occupying the marginal part of Oyachi makes the muddy fields of powdered peat filled with water throughout the year. The Fkita which mainly occupies the central part is rather recently reclaimed fields. In Oyachi there run very many waterways and “Yachibune” (a kind of boat) is used to carry fertilizer or rice plants. When the uncultivated part or a ridge 4_??_6m. wide between rice fields is stamped violently, the ground roundabout shakes. The peat layer can be penetrated with boring stick by one hand, and as soon as it is pierced through, no resistance is felt. When the boring stick is drawn out, brown liquid mud blows out with methane for 5_??_7 seconds, then it rests at the depth of 3_??_5c.m. from the surface. The subsidence of the surface of Oyachi took place during 1931_??_1952 amounted 60_??_90cm. as shown in Fig. 2.
Having an idea that Oyachi is a kind of bog lake, the writer made surveys in summer, 1953, at 423 points in Oyachi area on (a) thickness of the peat layer, (b) depth of the water lying beneath the peat, (c) thickness of the mud covering the base and (d) depth of the base from the surface of Oyachi. The results are shown in Fig. 3_??_8.
(a) Although thickness of the peat layer (Fig. 3) ranges from 1m. to 2m., it is generally thick at the central part and thin at the marginal part of Oyachi. The peat deposits are saturated and underlain by water of low temperature, so that, for example, when the surface temperature of Ukita is 29.8°C, the temperature at a depth of 50cm. is only 1.4.9°C. Therefore, growth of rice plants is poor, and even alpine plants grow there, though the altitude of the area is only 212m. above sea-level. (b) Fig. 4 shows the depth from the surface of peat layer to that of the mud, namely the shape of the lake basin. The deepest point is 8m. in depth, and besides there are three sub-lake basins. The southern half of Uyachi has only a depth between 2 and 4m. Fig. 5 shows the depth of Lake Hakuryih, which i s situated in the deepest basin of the Oyachi bog lake. The maximum depth of water, however, is only 1.9m. That is to say, the bottom of the lake is a false bottom. (4) Fig. 6 shows the shape of base of the bog lake by contour lines in altitude above spa-level. As the result of borings, six rises and eight hollows were discovered in the base. The lowest (deepest) portion coincides with the area of Lake Hakuryu. Comparing Fig. 6 with Fig. 4, it is observed the location of the deepest zones of the base deviates to the east from those in the lake basin, and unevenness of the former is remarkable. (c) Fig. 7 shows the thickness of the mud deposited on the base and it amounts 8m. at the deepest part. It proves that the lower the base lies the more the mud has been deposited. Fig. 8 is the cross section along A-B (see Fig. 1) showing the relation between peat layer, water, mud and base.
It had been planned to reclaim Uyachi by draining so as to make the area into a land suitable for cultivation, and the Biruzawa Reservoir with a pondage of 2, 190, 000m³. has been completed. Now the draining project is just to be carried on. But as the quantity of water in Oyachi bog lake amounts 20, 000, 000m³., it is necessary to make a draining canal from a point 12km. distant or to drain the area by electric power. After draining was accomplished, the writer thinks, it is necessary to bring enough soil from other places into the area or to take off the peat deposits from the area.

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