Manioc Agriculture and Sedentism in Amazonia: The Upper Xingu Example
Heckenberger, Michael J., Antiquity
Agricultural productivity and Amazonian settlement
The nature of Pre-Columbian agricultural systems in Amazonia has stimulated considerable debate, specifically: can one or another cultigen - maize or manioc - provide a stable agricultural base for sedentism and population growth (e.g. Cameiro 1961; 1986; Gross 1975; Meggers 1996; Roosevelt 1980)? Certain ecological factors are generally seen to limit production and intensification of those subsistence resources that can support sedentary or densely distributed populations. Low agricultural productivity, characteristic of many Amazonian soils, and the generally low density and patchy distribution of terrestrial game are commonly cited as limiting factors (Gross 1975; 1983; Johnson 1982; Meggers 1954; 1996; Ross 1978; Sponsel 1989). It has become accepted that the highly restricted varzea regions, primarily the floodplain settings of the major 'white-water' rivers (the Amazon and its Andean-derived tributaries), did not impose these environmental constraints on demographic or economic growth due to their fertile soils and higher concentrations of rich aquatic resources (e.g. Brochado 1984; 1989; Cameiro 1986; 1995; Denevan 1996; Lathrap 1968; 1970; 1987; Lathrap et al. 1985; Meggers 1996; Moran 1993; Roosevelt 1980; 1989; 1994).
In areas away from the varzea, the broadly-defined terra firme, the model of environmental limitation still has wide currency: '[u]nder extensive management systems, the increased labour time cost of subsistence production provides a strong incentive for groups to keep their settlement density low and move about frequently (520 year intervals)' (Gross 1983: 429). Many scholars, in fact, feel the incentive was so great as effectively to have prevented the development of large, permanent villages in upland areas characterized by low-fertility soils (e.g. Brochado 1989; Brochado & Lathrap 1982; Gross 1975; Meggets 1996; Roosevelt 1980; 1991; 1994). Certainly local ecology differentially constrains cultural development in Amazonia, but we adequately understand neither the parameters of ecological variability nor of cultural adjustments to it. The limits imposed on human populations by Amazonian nutrient cycles turn out to be substantially higher than analysis of contemporary societies might lead us to believe (e.g. Balee 1989; 1995; Beckerman 1979; Denevan 1992; Dufour 1994; 1995); manioc agriculture, even on low-fertility soils (utisols/oxisols), when combined with ample aquatic resources can provide a stable economic foundation for densely settled, fixed populations (see, especially, Cameiro 1957; 1961; 1986; 1995; Denevan 1996; Lathrap et al. 1985).
Heated debate continues over the subsistence base of Amazonian societies, particularly with respect to:
* the staple crops of the densely populated varzea societies [manioc, maize, or some similar seed-crop) and
* whether large, sedentary societies could develop elsewhere in the region; if so, did this also depend on staple foods other than manioc?
Debate is deadlocked because reconstruction of prehistoric diet remains largely speculative; most models are derived not from detailed analysis of an actual prehistoric pattern, but instead projected from ethnographic and human ecological patterns of contemporary groups. Those few studies which use archaeological data are often preliminary and depend almost exclusively on one or a few well-documented examples. Expanding interpretations from specific archaeological examples to broad regional patterns therefore depends on gross, and often unwarranted, generalizations regarding contemporary populations.
In the present discussion, ethnographic and archaeological evidence are reviewed which demonstrate:
* large, densely populated, and fully sedentary populations did exist in one non-varzea setting (the Upper Xingu) prehistorically;
* these populations relied primarily on bitter manioc and fish, as do their ethnographically known descendants; and
* increased productivity of these staple foods using an existing technology, and not technological innovation, provided the economic foundation for populous, sedentary social formations. …