Anthropogenic soil and settlement organisation in the Bolivian Amazon

Abstract

Anthropogenic soils known as Amazonian Dark Earths (ADEs) have long been known as a key component of subsistence systems for various pre-Columbian Amazonian populations. Often treated as a single category, ADE systems consist of two broad anthrosols (human-modified soils): the darker ADE (traditionally known as terra preta) and a lighter brown Amazonian Brown Earth (ABE; traditionally known as terra mulata). Data on the characteristics and spatial distribution of these anthrosols are severely lacking. Transects of soil test pits at the Triunfo and Versalles archaeological sites in the Iténez Forest, in the Bolivian Amazon, show variability in the distribution of soil types, revealing aspects of settlement organisation and resource management. Geochemical, isotopic and archaeobotanical data from an ADE, ABE and control soil profile from the Triunfo site, established ca. 500 cal BCE, characterise the two anthrosols as distinct components of a polyculture agroforestry subsistence system that combines anthropogenic soil fertilisation, closed-canopy forest enrichment, limited forest clearance for crop cultivation and low-severity fire management.