Water engineers in ancient South America were responsible for a remarkable feat that transformed seasonally flooded Amazonian savannas into thriving centers of year-round maize farming. The Casarabe people, an ancient civilization that once inhabited what is now northern Bolivia, constructed an innovative network of drainage canals and water-storing ponds that enabled them to cultivate maize twice a year.
According to a study published in Nature, led by geoarchaeologist Umberto Lombardo of the Autonomous University of Barcelona, the Casarabe society covered an area of 4,500 square kilometers and existed between 500 and 1400 AD. While previous excavations had revealed evidence of various crops and foods consumed by the Casarabe people, there was a lack of agricultural fields, raising questions about how they managed to sustain a large population.
The researchers utilized satellite images and ground surveys to identify clusters of human-made ponds in two savanna regions that were once inhabited by the Casarabe people. Canals connecting these ponds were mapped using a drone-mounted remote sensing technique called light detection and ranging (lidar), which revealed a sophisticated drainage system consisting of interconnected canals of increasing depth.
Soil samples taken from the edges of drainage canals and ponds contained phytoliths, microscopic mineral formations characteristic of maize cultivation. It is believed that the Casarabe people planted maize along the borders of canals and around the edges of ponds to ensure a continuous supply of the crop throughout the year.
While the exact age of the drainage system and other ponds remains unknown, radiocarbon dates for seeds and leaves suggest that one pond was in use from around 1250 to 1550. The researchers speculate that as the population of Casarabe grew and environmental pressures increased, the cultivation of maize provided a reliable and stable source of protein for the community.
This groundbreaking study sheds light on the ingenuity and resourcefulness of ancient civilizations in adapting to their environment and developing sustainable agricultural practices. The legacy of the Casarabe people lives on in the intricate network of canals and ponds that once enabled them to flourish in the Amazonian savannas.
