Smithsonian National Museum of Natural History

Amazonia’s Terra Preta

Were ancient native farmers managing
the soil?

South American Indians probably created terra preta—the fertile “dark earths” of the Amazon Basin. Did they do it intentionally? Or was it a by-product of the way they farmed, planting in partially burned clearings in the rain forest?

Slash-and-char farming between 2,500 and 500 years ago left areas of dark, highly fertile soils in the otherwise infertile red and yellow tropical soils. Soil scientists think that plant charcoal produced by this way of farming lasts for thousands of years and gives these soils their amazing ability to retain nutrients. New insights on this ancient practice may help present-day farmers raise crops sustainably.

Terra preta soil profile