An essay on the Boserupian model with particular emphasis on labour input and productivity in upland rice swiddens in Southeast Asia

Abstract

This study examined several aspects of Ester Boserup＇s model (1965), which has been highly influential in human ecological discussions on the dynamics of agricultural systems. The starting point of her model is that population pressure is the engine for changes in agricultural systems. For the cultivation stages prior to annual cropping, the result of the mathematical formulation devised in the present study is expressed by a simple equation whose independent variable is the population density in the territory of a community and dependent variable is the duration of fallow period of the fields in the territory. This equation can be graphically depicted as an equilateral hyperbola, although a few other factors may somewhat modify this basic pattern. This suggests that the fallow periods of the agricultural system of a community should be drastically shortened in the early phase of its population growth. At the next step, using a reasonably selected collection of available quantitative data originally obtained from upland rice swiddens in Southeast Asia, the assertion of the model that the labour productivity of a cultivation system with a longer fallow period is superior to that of a cultivation system with a shorter fallow period is tested. On the whole, the results do not confirm this assertion, most likely because such a test is strongly affected by local factors than by the common factor of the fallow period. Still, when the whole data of labour productivity are divided into those of the eight and the nine cases in the equatorial and the monsoonal zones, respectively, the results do roughly show the expected trend that labour productivity decreases with a shortened fallow period. Furthermore, if the two outliers of the nine values of the latter zone are excluded, this trend becomes highly noticeable and statistically significant.