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Terra Preta

February 20, 2006

Before Europeans arrived, the Amazon may have once supported a dense population. But with soil quality so low, how did those early Amazonians survive?

Transcript

BOB HIRSHON (host):
The secrets of ancient soils. I’m Bob Hirshon and this is Science Update.

Soil in the Amazon is so poor that farmers are forced to abandon fields after only a few years. But now soil scientists think that before Europeans arrived, early Amazonians treated the earth with charcoal—which made it remarkably fertile for hundreds or maybe thousands of years. This rich, ancient soil is called terra preta, and Johannes Lehmann of Cornell University is one of the scientists in hot pursuit of the exact recipe.

JOHANNES LEHMANN (Cornell University):
If we can discover the essence of what makes terra preta so fertile, we can remedy soil degradation worldwide.

HIRSHON:
What’s more, Lehmann says a modern charcoal treatment could be made by burning agricultural waste—an environmentally friendly process that would also yield energy.

I’m Bob Hirshon, for AAAS, the science society.