As reported in the August 9 issue of the journal Science, such long-lasting fertility is an anomaly in the tropics, where punishing conditions make the land highly acidic, low in organic matter and essential nutrients, and nearly incapable of sustaining life.
In 1994, James Petersen, associate professor and chair of anthropology at the University of Vermont, and Michael Heckenberger, now at the University of Florida, investigated their first terra preta deposit on a riverbank near Açutuba. The three-kilometer site was thick with broken pieces of ceramic, relics of a large, ancient society. To date, they and fellow researchers have excavated four sites and explored 30 others near the junction of the Amazon and Rio Negro.
What researchers find most remarkable is that instead of destroying the soil, the indigenous inhabitants improved it - something ecologists don't know how to do today. Although the project is in its early stages, modern scientists hope to learn the principles behind terra preta. The ability to reproduce the super-fertile soil could have broad impact, making it possible to sustain intensive agriculture in the Amazon and other hot regions.