タンザニア南部高地における在来谷地耕作の展開

抄録

The topography of the Southern Highlands of Tanzania typically consists of rolling hills and tangled streams with numerous shallow valleys. Swamps are formed at valley-bottoms, where rich organic matter accumulates due to the wet and cool climate. In this area, Bena practice indigenous dry-season cultivation called fiyungu, which is unique in two points: its drainage technology that enables the utilization of valley-bottom swamps; and its cultivation method that helps to decompose soil organic matter and neutralize soil acidity. Beans, maize and green vegetables are cultivated on fiyungu fields.
Fiyungu cultivation has been modified in line with socio-economic changes since the United Republic of Tanzania took its current form in 1964. Villagization, which led to increased population density, resulted in a shortage of land for fiyungu cultivation. To solve this problem, the Bena strengthened their drainage technology to utilize the wetter parts of swamps, and adopted chemical fertilizer and modified their cultivation method to enable repeated cultivation. Furthermore, economic liberalization led to commercialization of fiyungu beans, which were marketable during the off-season. The Bena thus started to cultivate beans for cash on fiyungu fields.
Fiyungu cultivation consists of indigenous agricultural technologies, which change valley-bottom swamps into useful arable land. The Bena have developed their own agricultural technologies in response to macro socio-economic changes in Tanzania. Their intimate knowledge of and attachment to valley-bottom cultivation gave their innovations an indigenous character.