Chronicle of Higher Education, December 3, 2004
Earth Movers Archaeologists say Brazil's rain forest, once thought to be inhospitable to humans, fostered huge ancient civilizations. The proof is in the dirt. By MARION LLOYD:
Iranduba, Brazil--High along bluffs overlooking the confluence of the mighty Negro and Solimões Rivers here, supersize eggplants, papayas, and cassava spring from the ground.
Their exuberance defies a long-held belief about the Amazon. For much of the last half century, archaeologists viewed the South American rain forest as a "counterfeit paradise," a region whose inhospitable environment precluded the development of complex societies. But new research suggests that prehistoric man found ways to overcome the jungle's natural limitations -- and to thrive in this environment in large numbers.
The secret, says James B. Petersen, an archaeologist at the University of Vermont who has spent the past decade working in the Brazilian Amazon, is found in the ground beneath his feet. It is a highly fertile soil called terra preta do indio, which is Portuguese for "Indian black earth." By some estimates, this specially modified soil covers as much as 10 percent of Amazonia, the immense jungle region that straddles the Amazon River. And much of that area is packed with potsherds and other signs of human habitation.
"This was one of the last archaeological frontiers on the planet. It's as if we know nothing about it," says Mr. Petersen, as he analyzes the discovery of the day, a series of circular carbon deposits that might indicate the outline of a prehistoric house. ....
Oilgood wrote:I'm asking if it is possible to re-create Terra Preta in other soils and climates throughout the world.
The research has implications not only for history, but also for the future of the Amazon rain forest. If scientists could discover how the Amerindians transformed the soil, farmers could use the technology to maximize smaller plots of land, rather than cutting down ever larger swaths of jungle. The benefits of what Mr. Petersen calls this "gift from the past" are already well known to farmers in the area, who plant their crops wherever they find terra preta. ...
"I know terra preta is very good and that it was made by the Indians," says Edson Azevedo Santos, a 48-year-old farmer drenched in sweat from weeding his zucchini patch. Unlike the acidic soil found in most of the rain forest, which can only sustain crops for a three-year period, terra preta plots can withstand constant farming for decades, if properly managed.
Even more striking, terra preta may have the capacity to regenerate itself, says Mr. Woods, the Southern Illinois geographer. He recently tested that possibility by removing a large section of terra preta on a plot near Santarem. To his amazement, the soil grew back within three years. "I suggested that the soil should be treated as living organism and that microorganisms are the secret," he says, adding that more research is needed to allow scientists to repeat the process. "This is very sophisticated stuff."
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