英領期ベンガル低地の開発と農業 : 史料による歴史地理的素描(<特集>バングラデシュの農業と農村)

Abstract

This article aims to describe the land reclamation process, its technique and the agriculture of the Bengal Lowland in the British period (1765-1947) from the view point of historical geography. The main historical sources used are Settlement Reports and District Records kept in the National Archives or District Collectorate Record Room and secondary materials. First, was divided the eastern portion of the Bengal Lowland (Bangladesh) into five large land-ecological categories : 1) alluvial fans, 2) floodplains, 3) tidal deltas, 4) marshes and swamps, and 5) Pleistocene terraces. The gradual eastward shift of the Ganges-Padoma from B. C. 300 to present and the abrupt westward shift of the Brahmaputra-Jamuna from the late 18th century to 1830s affected not only soil fertility and crop combinations, but also sanitary conditions and population growth. Under these conditions parts of the floodplains (Moribund delta), the tidal (western Sundarban) and Pleistocene terraces (Barind tract and Madhupur jangle) have an inactive nature, while other parts have an active nature. Annually inundated active floodplains show the climax of Bengal Lowland agriculture, with high productivity of rice and jute. Rice varieties were carefully selected by peasants according to microtopography, mainly, the level of inundation. On the other hand, landlords and the government have shown little interest in introducing flood control by embankments or canal irrigation. Barind, and exclusively aman-cropped area, was reclaimed before the late 19th century by hill tribes who migrated from and cleared the jungle surrounding areas. For tidal delta reclamation it is essential not only to clear coastal forest, but to prevent saltwater incursion by constructing embankments around paddy fields. Aman was exclusively grown there by permanent settlers or temporary ones. Marsh and swampy areas were the last frontier of lowland to be reclaimed because of the deep water there. Aman floating varieties or boro were dominant.