Terra Preta

In Amazonia, archaeological sites are often associated with Terra Preta do Indio also known as Amazonian Dark Earth, ADE, fertile anthrosols rich in organic matter and nutrients (e.g. Woods & McCann 1999). Interest in ADE has increased (Glaser et al. 2004; Lehmann et al. 2003; Woods and Denevan 2008) owing to their role in the debate on complex polities in Amazonia (Heckenberger et al. 1999; Petersen et al. 2001), agricultural productivity (Madari et al. 2004) and in suggesting that the Amazonian landscape to a considerable extent is anthropogenic (Oliver 2001).

A peculiar quality about these soils is their stability. Although the settlements that once somehow produced them in most cases vanished in the 16th and 17th centuries, the soils have not become leached or decomposed. In fact their fertility implies that they are the most coveted soils for agricultural purposes in the Amazon today. As a consequence the archaeological record is being destroyed at an alarming rate. ADE are anthropogenic soils, hence restricted to areas affected by human activity and presumably formed through the deposition of organic material from human activities.

These soils have comparably high pH, high organic content, high concentrations of P, Ca, Mg, Mn, besides being remarkably resistant to leaching. Given their persistence through time, they provide unique clues for settlement chronology and demographic density. The possibility that ADE was produced intentionally as a strategy of soil improvement has been stressed by several scholars (e.g. Steiner et al. 2008). Suggested procedures for soil enhancement include particular methods of clearing, usually referred to as “slash and char”, in which pyrolysis (a burning method with limited supply of oxygen) is the dominating type of burning, possibly combined with the addition of various kinds of organic waste (e.g. Steiner et al. 2004). The degree of intentionality behind the human-driven formation of the ADE and related environmental modifications has yet to be evaluated.

Bibliography

Glaser, Bruno, Wolfgang Zech and William I. Woods
2004 History, Current Knowledge and Future Perspectives on Geoecological Research Concerning the Origin of Amazonian Anthropogenic Dark Earths (Terra Preta). In Amazonian Dark Earths: Explorations in space and time, edited by Bruno B. Glaser, and William I. Woods, 9–17. Springer, Berlin.

Heckenberger, Michael J., James B. Petersen and Eduardo Goés Neves
1999 Village Size and Permanence in Amazonia: Two Archaeological Examples from Brazil. Latin American Antiquity 10(4):353–376

Lehmann, Johannes, Dirse C. Kern, Bruno Glaser and William I. Woods (eds.)
2003 Amazonian Dark Earths: Origins, Properties, Management. Kluwer Academic Publishers, Dordrecht.

Madari, Beata Emöke, Wim G. Sondroek and William I. Woods
2004 Research on anthropogenic Dark Earth Soils. Could it be a solution for a sustainable agricultural development in the Amazon? In Amazonian Dark Earths: Explorations in space and time, edited by Bruno B. Glaser and Willian I. Woods, pp. 169–181. Springer, Berlin.

Oliver, José R.
2001 The archaeology of forest foraging and agricultural production in
Amazonia. In Unknown Amazon: Culture in nature in ancient Brazil. Edited by C. McEwan,
C. Barreto & E. Neves, pp.50-85. The British Museum Press, London.

Petersen, James B., Eduardo Goes Neves, and Michael J. Heckenberger
2001 Gift from the Past: Terra Preta and Prehistoric Amerindian Occupation in Amazonia. In Unknown Amazon, edited by Colin McEwan, Cristiana Barreto, and Eduardo G. Neves, 86-107. British Museum Press, London.

Steiner, Christoph, Wenceslau Geraldes Teixeira and Wolfgang Zech
2004 Slash and Char: An Alternative to Slash and Burn Practiced in the Amazon Basin. In Amazonian Dark Earths: Explorations in space and time, edited by Bruno B. Glaser, and William I. Woods, 183–194. Springer, Berlin.

Woods, William I. and William M. Denevan
2008 Amazonian Dark Earths: The First Century of Reports. In Amazonian Dark Earths:  Wim Sombroek's Vision, edited by William I. Woods, Wenceslau G. Teixeira, Johannes Lehmann, Christoph Steiner, Antoinette WinklerPrins, and Lilian Rebellato, 1–14. Springer Dordrecht Netherlands.

Woods William I, and McCann J.M.
1999 The Anthropogenic Origin and Persistence of Amazonian Dark Earths. In Yearbook 1999 - Conference of Latin Americanist Geographers, Vol 25, edited by C. Caviedes, 7–14.University of Texas Press, Austin.