| Abstract: |
| In response to a perceived absence of research differentiating sustainable from non-sustainable forms of slash-and-burn agriculture, this study evaluates the ecological sustainability of traditional upland rice farming using agroecological indicators. Employing a working definition of ecological sustainability -- that impacts to ecological resources not interfere with satisfactory long-term agricultural production -- near- and long-term changes in soil resources were quantified. Field work was conducted in the Dayak village of Kembera, West Kalimantan, Indonesia during the fall of 1993.
A chronosequence of sites ranging from current swiddens to a 28-year fallow was surveyed. Concentrations of available basic cations (potassium, magnesium and calcium), available phosphorus, nitrate, cation exchange capacity, pH, available aluminum and available iron were measured.
Results indicate that soil chemical conditions do not significantly decline over the long-term. This suggests that slash-and-burn farming in Kembera is ecologically sustainable. Near-term trends point to a marked improvement in the agronomic quality of soils during the cropping period, a necessary characteristic of ecologically sustainable slash-and-burn agriculture. However, crop production may be limited by available phosphorus.
Fallow period trends reveal a general absence of significant differences in pH, basic cations, iron and aluminum between study plots. While nitrate and cation exchange capacity do increase with the age of the fallow, a lack of organic matter data restricts insight into the role of the fallow in long-term soil resource management.
Recent changes in variables affecting land use threaten to upset the ecological sustainability of slash-and-burn agriculture in Kembera. If the ecological sustainability of the Kembera agroecosystem is to persist, steps must be taken to addreass land tenure security, income security and population growth. |
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