In Japan the area of mulberry-fields which was grestest in 1930 has reduced very rapidly since that time, and the decay of mulberry-fields is remarkable in Western Japan. At present mulberry-fields are concentrated and remain in a limited area, particularly in the western part of Japan. Such a decline of mulberry-fields has had an influence on the utilization of land, especially that of farm fields. Some time ago I surveyed the region of mulberry-fields in the Yura valley of Kyoto Prefecture, and in the Hokusei district of Mie Prefecture, to explain the relation between the decrease of the area of mulberry-fields and the change of agricultural stracture, taking into consideration the local conditions that act upon the concentrated distribution of mulberry-fields.
Recently I have investigated the mulberry-fields of Kumamoto Prefecture, which has the broadest mulberry-fields in Western Japan.
The outline of these studies is as follows:
(1) The eminant districts of mulberry-fields in Kumamoto Prefecture are the basins of the Kikuchi and the Midori. The remaining mulberry-fields are distributed, topographically, into two parts: the hill land of the diluvial formation near the valleys, and the floodplains; and from the point of the constitution of arable land, they are not in the dominant areas of paddy fields or farm fields, but in regions where there are 40%-70% paddy fields. Formally we could see mulberry-fields along the seaside area and in the low land of the outskirts of Kumamoto. But recently they are concentrated in the middle basins of the Kikuchi and the Midori.
(2) In the region of mulberry-fields we could see, outwardly, that mulberry-fields compete with orchards, especially with those of citrus fruits and grapes, and they coexist with the breeding of cattle, particularly cows.
The former has played an important part in the decrease of mulberry-fields, and the latter in the maintenance of them.
(3) The remarkable decrease of the mulberry-fields in the seaside areas has been caused by the increase of orchards, particularly citrus fruits. At present the orchards are distributed principally upon the coastal region whose center is at the W. and N.W. foot of the Kinpo highlands, and lie scattered in inland area. Many an orchard has been transformed from mulberry-fields directly or indirectly.
Recently the orchards are spreading and encroaching upon the mulberry-fields. These tendencies are remarkable in seaside areas; meanwhile, in inland areas, the dimension of scatterd orchards is expanding as a ripple and competing with the surrounding mulberry-fields. Owing to the increase of the orchards, mulberry-trees and silk-worms are badly damaged by agricultural medicines scattered in the orchards, and labour is confined to the orchards. So it is difficult to maintain these two (the orchard and the mulberry-fields) concurrently.
(4) In Kumamoto Prefecture we could see cattle distributed at the foot of the Kyushyu-mountains, the islands and the Kikuchi, the Midori basins, . Inside the mulberry-field areas regionally the distribution of fields and cattle coincides, and farmers generally manage both together. Between them we could see positive coextence, for instance, farmers use their stable manure for mulberry-trees, and sericulturists give silkworms faces and litter for cattle, and they grow feed-crops among the mulberry-trees.
In the region of sericulture, when farmers breed cattle they regard the cattle as of mutual assistance to seliculture, and do not stress the point of labour.
(5) A farmer of sericulture has more employment cattle than one who has no sericultural interest; the former has not so many milkcows as the latter.
We could generally see positive interdependence between the seliculturist and the breeder of employment cattle, but with milking cows we could not see any positive interdependence, except in limited areas, due to the competition of labour.
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