A team of researchers has recently uncovered that a pre-Columbian society in the Amazon developed an advanced agricultural engineering system, enabling them to cultivate maize year-round. This revelation challenges earlier beliefs that ruled out the possibility of intensive monoculture farming in the area.
Recent research by a group from the Institute of Environmental Science and Technology (ICTA-UAB) and the Department of Prehistory at the Universitat Autònoma de Barcelona (Spain), alongside universities in Exeter, Nottingham, Oxford, Reading, and Southampton (UK), and the University of São Paulo (Brazil) with Bolivian collaborators, reveals that a pre-Columbian society in the Amazon created a complex agricultural engineering system that allowed for year-round maize production. This discovery contradicts prior theories that dismissed the idea of intensive monoculture agriculture in the region.
The findings, released today in the journal Nature, detail how the ancient Casarabe society in the Llanos de Moxos region of Bolivia constructed an innovative landscape engineering system, including extensive drainage canals and farm ponds. This advancement converted flooded tropical savannahs into highly productive agricultural lands, contributing to what is known as the “Neolithic Revolution” in the Amazon—transitioning toward a grain-based economy.
The Casarabe people lived in this tropical lowland savannah between 500 and 1400 A.D., characterized by heavy rains, flooding, and extremely dry spells. The discovery, spearheaded by Umberto Lombardo, an environmental archaeologist at UAB, has revealed a unique agricultural infrastructure that has not been documented elsewhere globally. This system allowed the effective drainage of excess water during the rainy season, enhancing agricultural efficiency. Additionally, the Casarabe people built clusters of farm ponds that acted as reservoirs, permitting pot-irrigation and allowing maize farming to continue during dry periods.
This sophisticated water management system enabled them to achieve at least two maize harvests each year, ensuring a consistent food supply that was essential for supporting a relatively large population. “This intensive agricultural method shows that maize was not merely cultivated but was likely the primary crop of the Casarabe culture,” Lombardo states.
Unlike conventional slash-and-burn methods used for clearing fields, the Casarabe people maintained nearby forests for purposes such as firewood and medicinal plants, while adopting practices that optimized water and soil use in the seasonally flooded savannas.
The team’s conclusions were reached through careful fieldwork, employing techniques like microbotanical analysis, remote sensing, and environmental archaeology. Analyzing 178 samples of phytoliths (plant microfossils) and pollen from a farm pond confirmed the presence of maize in the fields and highlighted the crucial role of maize monoculture in this society’s diet. “The data indicates a lack of other crop types,” Lombardo notes.
“We can confirm this as the first grain-based agrarian economy in the Amazon, where previously it was believed that the agriculture relied on agroforestry polyculture, and not on large-scale monocultures. This understanding changes our perspective on the Llanos de Moxos,” claims Lombardo, emphasizing how this engineering innovation transformed a difficult environment into a productive agricultural system, thereby ensuring food security for a growing population.
This research not only illuminates the technological prowess of pre-Columbian societies but also provides valuable insights for contemporary agricultural sustainability. This finding underscores the creativity and resilience of the Casarabe people, who succeeded by developing long-term sustainable farming solutions in a challenging environment.
