Latin America

Engineered waterways helped Casarabe people turn savannas into year-round crop fields


By Bruce Bower

January 29, 2025 at 11:00 am

Water engineers in ancient South America turned seasonally flooded Amazonian savannas into hotbeds of year-round maize farming.

Casarabe people built an innovative, previously unrecognized network of drainage canals and water-storing ponds that enabled two maize harvests annually, say geoarchaeologist Umberto Lombardo of the Autonomous University of Barcelona and colleagues. Large-scale maize cultivation during rainy and dry parts of the year fed the rise of Casarabe urban sprawl across Amazonian forests and savannas in what’s now northern Bolivia, the scientists report January 29 in Nature.

Previous excavations dated Casarabe society, which covered an area of 4,500 square kilometers, to between the years 500 and 1400. Casarabe people had access to a variety of foods and crops, including maize, starchy tubers, squash, peanuts and yams. But investigators have found no evidence of Casarabe agricultural fields, raising questions about how farmers grew enough food to sustain a substantial population.




Maize planted around a pond and along the edge of a canal, as in this illustration, may have helped Casarabe people grow the crop all year long.
U. Lombardo et al/Nature 2025


Rather than exploiting a range of available crops, Casarabe people transformed savannas into maize-production centers, the researchers say. “As the population grew and environmental pressures increased, perhaps they looked for more reliable and stable sources of proteins,” Lombardo suggests. “Maize could have offered that to some extent.”

More:
https://www.sciencenews.org/article/maize-farmers-amazonians-casarabe