Amazonians Turned Poor Land Into Great Farms—and Healthy Ecosystems

By Andrew Moseman | April 13, 2010 4:09 pm


The people who lived in the Amazon regions back before any Europeans showed up on the scene had an ingenious way to survive there. By creating mounds of biochar, the pre-Columbian peoples made beds for their crops that drained far better than the native soil, which is nutrient-poor and prone to flooding. And, it seems, they unintentionally contributed to the biodiversity of the region.

In a study in the Proceedings of the National Academy of Sciences, scientists led by Doyle McKey of France investigated the savannas of French Guiana, in the far northern part of South America. These plains are flooded during the rainy season, dry and parched in the summer, and often burned by fires. It was while walking through this landscape that McKey started wondering about undulations in the terrain [New Scientist]. Just how effective were these people at creating favorable cropland? McKey found that the drainage capacity of the mounds was nine times that of the rest of the savanna.

As DISCOVER noted in the 2007 feature “Black Gold of the Amazon,” the nutrient-rich, fertile soil that resulted from the biochar mounds is a gold mine for local farmers even today. But it was the insects who really appreciated the gifts of the pre-Columbian peoples after those people disappeared. Species of ants and termites settled in the mounds, where their colonies wouldn’t flood. Their burrowing aerated the soil, and plant matter foraged from surrounding areas enriched it further. As a result, the mounds acted like sponges for rainfall, and outsourced insect labor made them rich in key fertilizer nutrients of nitrogen, potassium and calcium []. Because of the plentiful nutrients, plants on these mounds grew more successfully and their roots reached deeper.

All in all, McKey argues, the actions of those humans trying to better their agricultural situation actually improved biodiversity compared to what had been there before, the flat savanna. That’s not bad for a civilization about which our knowledge is extremely limited, and you can count McKey among the people who think that simple agriculture secrets like biochar could teach us something. “When people modified these ecosystems long ago, they changed the way the ecosystems work. We can use that knowledge,” said McKey [].

Related Content:
DISCOVER: Black Gold of the Amazon
Discoblog: The Softer Side of Climate Control?
80beats: Ancient Agriculture Trick, Not High-Tech Engineering, Is Best Climate Defense

Image: Pre-Columbian raised fields around French Guiana, including on the left bank of the Mana River (A), near the Sinnamary River (B), west of the city of Kourou (C), and between the town of Macouria and Cayenne Island (D). Credit: McKey et. al. / PNAS

  • MNIceLady

    What does each photo represent?

  • Andrew Moseman

    @MNIceLady They’re just different examples of the raised terrain from around French Guiana, as seen from above.

  • Jennifer Angela

    Now there´s a bunch of people who know how to make lemonade out of lemons! Reminds me of me…

    Apart from that I am fascinated (once again, as I begin to remind myself of the abilities of insects thanks to you folks) by the usefulness of nature´s not so pretty and unfortunately also quite annoying little creatures referred to as insects. That ought to support all of us at bearing every day life with insects a little bit better.

  • Jennifer Angela

    I did tend to assume that these fotos depict the before and after state of fields before and after they had been taken care of in a very dilligent way as described above. Ouch! Major conclusion default!


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