Amazonian Dark Earth: A Model of Sustainable Agriculture of the Past and Future?
Across the Amazon Basin, vestiges of Pre-columbian indigenous settlements can be found in the form of dark, fertile soils known as “terra preta do índio” or Amazonian Dark Earth (ADE). Today, ADE has been touted as a potential model for sustainable agriculture in Amazonia and beyond. Pedological studies have shown that pyrogenic carbon (black carbon, charcoal) is a key feature of the soil, exhibiting many important functions that enhance nutrient availability and soil organic matter (see Glaser et al. 2003; Lehmann et al. 2002). In addition to heightening agricultural production, pyrogenic carbon is considered to also be an efficient carbon sink. These factors have propelled the terra preta phenomenon from relative obscurity to the attention of international agronomists and environmentalists. The media have also caught wind of the ADE phenomenon and have produced enthusiastic (although perhaps overly optimistic) articles about the potential of ADE for curbing global warming and promoting environmentally-sound agriculture. This paper seeks to illuminate the history of Amazonian Dark Earth, describing its initial scientific recognition and the development of international research projects dedicated to the study of the soil. This historical overview is followed by a discussion regarding the intended application of the ADE model for the development of a carbon sequestration/soil fertilization technology in the global market. Finally, this work addresses how pyrogenic carbon technologies can be adapted to meet the needs of rural smallholders of Amazonia, the originally intended beneficiaries of ADE studies.
Keywords: Amazonian Dark Earth, Terra Preta do Indio, Sustainable Agriculture, Carbon Sequestration
Nicholas C. Kawa
Ph.D. Student, Department of Anthropology, University of Florida