In the face of mass deforestation of the Amazon, recent findings indicate that modern farmers could learn from the region’s earliest known inhabitants, who managed their farmland sustainably. 

An international team of archaeologists and paleoecologists have discovered that indigenous people, living in the savannas around the Amazonian forest, farmed without using slash and burn techniques, instead adopting sustainable farming techniques to reduce the impact on their land. 

The research, published earlier this week in the journal Proceedings of the National Academy of Sciences, could provide insights into the sustainable use and conservation of such globally-important ecosystems, which are being rapidly destroyed. Pressure on the Amazonian savannas today is intense, with the land being rapidly transformed for industrial agriculture and cattle ranching.

By analyzing records of pollen, charcoal and other plant remains like phytoliths spanning more than 2,000 years, the team has created the first detailed picture of land use in the Amazonian savannas in French Guiana., giving a unique perspective on the land before and after the first Europeans arrived in 1492.

The research shows that the early inhabitants of these Amazonian savannas practiced ‘raised-field’ farming, which involved constructing small agricultural mounds with wooden tools. These raised fields provided better drainage, soil aeration and moisture retention: ideal for an environment that experiences both drought and flooding. The fields also benefited from increased fertility from the muck continually scraped from the flooded basin and deposited on the mounds. The raised-field farmers limited fires, and this helped them conserve soil nutrients and organic matter and preserve soil structure.

“We used radiocarbon dating to establish the age of the raised beds,” said Dr. Mitchell Power, a Utah Natural History Museum curator and professor at the state’s University.  “We came to the conclusion that corn pollen we found dated to 800 years ago by dating charcoal deposits from above and below the sediment where the pollen was found.”

It has long been assumed that indigenous people used fire as a way of clearing the savannas and managing their land. However, this new research shows that this was not the case here. Instead, it reveals a sharp increase in fires with the arrival of the first Europeans, an event known as the ‘Columbian Encounter’. The study shows that this labour-intensive approach to farming in the Amazonian savannas was abandoned when as much as 95 percent of the indigenous population was wiped out as a result of Old World diseases, brought by European settlers.

Dr José Iriarte of the University of Exeter, lead author on the paper, commented on the potential impact of the study, which comes just months before world leaders will meet in Rio de Janeiro to discuss methods of alleviating poverty and setting the world on a more sustainable course. He said, “This ancient, time-tested, fire-free land use could pave the way for the modern implementation of raised-field agriculture in rural areas of Amazonia.

“Intensive raised-field agriculture can become an alternative to burning down tropical forest for slash and burn agriculture by reclaiming otherwise abandoned and new savannah ecosystems created by deforestation. It has the capability of helping curb carbon emissions and at the same time provide food security for the more vulnerable and poorest rural populations.”

The researchers believe the raised-field systems used eight hundred years ago can be just as productive as the human-made black soils of the Amazon, but with the added benefit of reducing carbon emissions.

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