Shifting cultivation and health conditions of the Karen hill tribe in northern Thailand: connection and sustainable intervention?

Abstract

Traditional agroecosystem management practices of the Karen hill tribe in northern Thailand are in the process of transformation. Their land use systems traditionally included a shifting cultivation component characterized by a rotational cycle of land clearing, burning, cropping for 1-2 years, and relatively long fallow period of at least 10 years. Plants in regenerating secondary forest fallow areas restored soil fertility for the next cropping cycle. Although shifting cultivation often invokes images of massive forest destruction and land degradation, various studies have shown that rotational systems with these characteristics can be sustainable. During recent decades, however, the area of cultivated land per capita has been declining with population growth and environmental restrictions, resulting in shortened fallow period s. This will likely lead to declining soil Page 1 of 20fertility, resulting in lower productivity of upland rice, and eventually in in sufficient subsistence food supplies. As some studies indicate that species richness in regenerating secondary forest fallow areas are higher than in some primary forests and most permanent agricultural areas, shorter fallow periods may bring loss of late-fallow species of nutritional and ecological importance. As a consequence, there is a significant risk that the Karen will experience both declining land productivity and inadequate food supplies, which could be expected to result in malnutrition and related deseases