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J.M. McCannet al.
OMandAnthrosolsin Amazonia
3.10
Organic Matter and
Anthrosols in Amazonia:
Interpreting the Amerindian
Legacy
J.M. M
C
C
ANN
1
, W.I. W
OODS
2
AND
D.W. M
EYER
3
1
Division of Social Sciences, New School University, New York,
NY 10011;
2
Department of Geography, Southern Illinois University,
Edwardsville, IL 62026; and
3
Rock River Laboratory Inc., N8741
River Rd,Watertown, WI 53094, USA
Introduction
Amazonian dark earths (ADE), commonly referred to as
terra preta do Índio
,
occur in a variety of landscape contexts throughout Amazonia in patches
ranging in size from less than a hectare to many square kilometres. During
the last 30 years, research by soil scientists employing diverse sampling and
analytical methods has produced a sizable body of data describing these
anomalous soils (e.g. Falesi, 1972; Kern and Kampf, 1989; Pabst, 1991;
Glaser, 1999). ADE exhibits a wide range of chemical and physical proper-
ties, though the following suite of persistent characteristics distinguishes
them from surrounding oxisols and ultisols: dark colour, high nutrient
content, high soil organic matter (SOM), high pH and association with
cultural debris. Recently, ADE has attracted increasing attention from
geographers, anthropologists and others who are interested in what the
soils may reveal about prehistoric lifeways and settlement patterns (e.g.
Smith, 1980; Mora,
et al
., 1991; Heckenburger
et al
., 1999). Nonetheless,
important basic questions regarding origin, formation, persistence, varia-
tion, distribution and use remain unresolved. Most discussions of ADE
assume that it is a single definable soil type created by the accumulation of
human waste debris in the context of long-term habitation. This chapter
has three objectives. First, we assess the validity of this prevailing 'midden'
model of dark earth formation. Secondly, we propose a more detailed
classification of ADE that reflects its variability. Thirdly, we discuss the
implications of our findings for management of tropical soils.
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