Fallow Period and Transition in Shifting Cultivation in Northern Thailand Detected by Surveys of Households and Fields

抄録

The purpose of the present study was to analyze the changes in the location of shifting cultivation fields, mainly of upland rice fields, in northern Thailand. Practically, the authors examined the land use history of two households in a Yao (Mien) community from 1980 to 2005. Rotational use, in which the same field is reused at an interval of several years, was confirmed in nine cases based on the annual changes in the location of upland rice fields. The duration of the average fallow period was similar for both households, namely, 5.0 years and 4.5 years after the late 1980s. The actual fallow period was highly variable, however, depending on the fields. A distribution of 1-10 years and 1-13 years was apparent in the fallow period for each household. The time when each household stopped using the fallow system differed depending on the strips of field, and the year when this first occurred was 1995 for one household and 1999 for the other. Our results underscored the variety of the processes involved during the transition from the shifting cultivation system to the permanent system for field cultivation or forestry, depending on both households and strips of field.