Research by a University of Kansas professor and his colleagues showing that ancient Amazonia may have supported large-scale agriculture is challenging conventional thinking and providing ideas for more efficient and environmentally friendly land use in the future.
William Woods, professor of geography, has researched patches of dark, fertile soil interspersed among the largely unproductive, poor soil the region is known for. He’s concluded the soil was enriched by ancient inhabitants to support the growth of crops such as maize to feed settlements of up to hundreds of thousands of people. He recently shared his findings at the annual meeting of the American Association for the Advancement of Science in St. Louis.
For years, the conventional thinking was that Amazonia never could, and never did, support agriculture. The many dark patches of fertile soil have provided clues that inhabitants deliberately enriched it for crop growing. Most of the patches are small, some much larger, about the size of Lawrence, Woods said.
“They definitely could have produced large amounts of food,” Woods said.
He thinks inhabitants enriched the soil by adding household waste and using a method called slash and char.
Slash and char differs from the more established practice of slash and burn. Slash and burn was a high temperature fire that emitted a lot of gas and didn’t add much to the soil.
Slash and char was a much lower-temperature, smoldering method that added more carbon and organic material to the soil. Practitioners likely burned vegetation while it was still green, resulting in a slow burning fire, then added more wet, green vegetation to keep it that way. The result would have been soil rich with carbon that could last up to 50,000 years, Woods said. It also challenges the established belief that inhabitants of Amazonia were mostly nomadic.
“It’s turning the former thinking about the archaeology of Amazonia on its head,” Woods said.
The findings have important potential for the future as well. Woods is consulting with the Brazilian government to discuss how the ancient method can be used today. Along with Kevin Price, professor of geography and associate director of the Kansas Applied Remote Sensing Program, Woods will apply for a grant to use satellite remote-sensing technology to find the scattered fertile areas of Amazonia for more in-depth study.
If the modern method can be applied it can enrich soil to produce food across the world, while taking carbon emissions from fossil fuel out of the environment, Woods said.
The research about Amazonia’s past could also help secure its future.
“It’s very important,” Woods said of the research’s potential. “Not only for understanding the past in Amazonia, but if people could practice this today, you might not have to clear the forests.”