Terra Preta in the Amazon

Most people believe that the Amazon Rainforest is nothing but a virgin paradise of untouched wilderness. Recent studies have shown, however, that much of the Amazon might very well have been a landscape designed by the patient persistence of indigenous cultures who interacted with the land and the local ecosystems. What if the Amazon Rainforest wasn’t really an intact wilderness area, but rather the result of careful human planning over thousands of years?

The terra preta, or black earth, is a recent discovery that gives rise to the likelihood of the Amazon Rainforest being a carefully structured environment instead of a pristine wilderness. This hypothesis believes that the abnormally black and fertile earth found scattered around the Amazon Rainforest was of the techniques used by indigenous cultures to maintain the fertility of one of the most vulnerable and important ecosystems on earth.

Wasn’t the Amazon a Virgin Paradise?

In our middle school geography class, chances are that we saw a video on the vastness of the Amazon Rain Forest. We might have been told that the Amazon was the last great “wild” area on earth, the lung for our planet, and an essential ecosystem providing our world with enormous amounts biodiversity from where we get the raw materials for our medicines and antibiotics.

While this outlook on the Amazon Rainforest isn´t exactly incorrect, it doesn´t quite tell the whole story. We have always known that hundreds of indigenous cultures have inhabited the Amazon Rainforest. Even today, there are continuous reports of the sighting of untouched indigenous groups who have lived in the depths of the forest out of the reach of our seemingly all-encompassing industrial civilization.

Perhaps stemming from the guilt that is tied to our industrial pillage of the natural world, we have held onto a somewhat romantic view of indigenous cultures that live in complete harmony with the industrial world. Living in harmony with the natural world, according to our understanding, would entail harvesting the fallen fruits from the untouched and unscathed forest floor and spending our nights sleeping in the forest canopy. The blockbuster hit “Avatar” did a good job offering us a vision of what that harmony might look like.

Recent evidence has shown, however, that the Amazon, far from being an unmarked wilderness where humans and monkeys and jaguars peacefully co-existed, might actually have been a designed landscape; the “farm” of hundreds of indigenous cultures scattered throughout the forest.
While this hypothesis might contradict our vision of the Amazon as an untouched wilderness, the abundance of an uncharacteristically black and fertile soil known as “terra preta” is bringing into question long-held assumptions about one of the most beautiful and important ecosystems on the earth.

What is Terra Preta?

The Amazon Rainforest is undoubtedly one of the most biodiverse and resilient ecosystems on our earth. It is rather ironic, however, that the soil beneath the lush forest canopy is some of the most infertile and degraded soils on earth. In tropical regions of the world, fertility is maintained through the continual recycling of plant growth. The plants, bushes, and trees that make up the different levels of the rainforest canopy are the fertility of that ecosystem while the soils are generally shallow and made of heavy clay content.

Homemade terra preta, with charcoal pieces indicated using white arrows. (photo credit: Wikipedia)

In various regions around the Amazon Rainforest, however, large areas of black and fertile soil have been found. This soil doesn’t only differ from the soil from the entire surrounding landscape, but rather has been found to be composed of charcoal (burned wood), bone meal and other organic ingredients. Scientists have come to believe that this soil is anthropogenic, meaning that it is human created. Whereas our modern-day society has been wasting soil, the ancient Amazonian cultures patiently built huge amounts of fertile soil that allowed them to subsist in specific regions for extended periods of time. These areas of terra preta range are scattered throughout the Amazon lending to the hypothesis that, far from being a virgin wilderness, groups of people have inhabited the Amazon for thousands of years. The terra preta landscapes differ in size from 1 to 80 hectares.

Why was Terra Preta Important?

The discovery of terra preta shows that it is completely and entirely possible to live in a bioregion without destroying the ecological health of that area. Whereas our Western culture has been characterized by ruining the environmental health and depleting the natural resources of one area before moving on to the next area, the Amazonians lived for close to 2,500 years in one of the most diverse yet vulnerable ecosystems on our earth without ruining that environment. In fact, through improving the soil with terra preta practices, the ancient Amazonians were able to grow a greater number of crops, thus augmenting the diversity of the ecosystem even more.

Another name for terra preta is biochar. By incorporating woody waste that has been burned into the soil, the ancient Amazonian cultures were creating habitat for billions of fungi, bacteria, and other important soil organisms. Whereas the Amazonian soil itself was too acidic to foster healthy soil life, by adding biochar, the people of the Amazon were able to fundamentally change (for the better) the quality of the soil.

What Can We Learn from the Practices of the Indigenous Cultures of the Amazon?

Finding ways to interact positively with the world around us is a fundamental lesson that our modern-day civilization needs to learn. When we think of the ways in which humanity has affected the world, we almost think of negative and harmful aspects such as climate change, pollution, depletion of the ozone layer, etc. The example of terra preta, however, should show us that it is entirely possible for humans to affect positive change on the world around them through careful observation.

Over 2,500 years ago, an ancient and obviously pre-technological culture was able to find a way to increase the fertility of the land they inhabited. Over several centuries of incorporating charcoal, bone remains, and manure into the soil, the terra preta of the Amazon was able to reach depths of over 2 meters deep. Amazingly, this technique can and should still be used today in our modern-day agriculture. Biochar can continue to be produced through the burning of crop residues, excess wood, and other organic materials. Incorporating this material into our depleted agricultural soils will increase natural fertility and the microbial activity of the soil.

Additionally, biochar can also help to pull excess carbon from the atmosphere and “fix” it in the soil. Some authors have called this practice “carbon farming” and it shows how an ancient agricultural practice can be used today to help combat one of the biggest dangers we collectively face: global climate change.

Terra Preta and the Promise of Positive Human Interaction with the World

In this day and age of our human domination of the natural world, it is refreshing to hear of ancient cultures that were able to shape their natural surroundings for their own purposes while still maintaining the health and resiliency of those ecosystems intact. The buildup of terra preta around the Amazon offers a glimpse into how indigenous cultures around the world found ways of living sustainably in their places. It also should challenge us to continue to find ways to live more sustainably ourselves.

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3 thoughts on “Terra Preta in the Amazon

  1. Terra preta is interesting stuff, and so is biochar.. I wouldn’t say biochar is another word for terra preta, though. That’s kind of like saying that flour is another word for bread. Biochar is one of the ingredients of terra preta, along with humanure, bones and other stuff.

  2. Great article!; thanks,
    You say that this technique helps fixing co2 in the soil, but the co2 liberated in the process of burning the wood woudn´t be worse than the effect?, what is the ralation of burning and fixing carbon with terra preta?.

  3. Thanks for the nice article. I have been using charcoal for a long time in soil recuperation, particularly in gardens that get that worn out look. The plants are all there but they seem to lack enthusiasm after years of rain and the soil becoming compacted (in a house garden). In agriculture and reafforestation I use Bokashi which has charcoal as part of its ingredients. It seems that terra preta and other recuperative ‘ techniques ‘ always involve complementary compounds where relationships are formed and reformed between the mineral, vegetable and animal. Bio dynamics works this well. Thanks

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