Amazonian Terra Preta

Once in a while you run across something that challenges just about everything you thought you knew. “Terra preta” (Portuguese for “black earth”) are anomalous deposits of deep, rich soil found in large pockets of land throughout the Amazon. Once thought to be 100% comprised of thin, fragile soil that would immediately desertify if the trees were removed, it now turns out there are significant sections of Amazonia where this terra preta is abundant. But the biggest mystery is this: The Amazon’s best soil, terra preta, possibly was deliberately created by Native Americans.

The Amazon basin’s best soil, agrichar, possibly
was deliberately created by Native Americans.

As put forth in 2002 in a lengthy article in the Atlantic Monthly entitled “1491″ by Charles C. Mann, there is a growing body of evidence that the indigenous population of the Americas in pre-colombian times was far greater than is typically estimated.

In Mann’s report several thought provoking bits of evidence are presented: The great mass of carrier pigeons that filled the skies and the great masses of bison that dominated the endless prairies in the 18th century were not always there – if they had always been there, in archeological sites we would see their bones in far greater abundance. Instead they were “outbreak species,” whose numbers mushroomed in the wake of human demographic collapse. Read the article for more arguments supporting this new theory – which basically says the impact of European disease on Native American populations was far, far greater than previously conjectured, and in fact abruptly destroyed a network of complex urban civilizations numbering well over 100 million people.

The presence of Amazonian terra preta is another piece of evidence allegedly supporting this theory, because the placement of these deposits of charcoal rich black earth are not explained without human intervention. The theory holds that this black earth was created by a process called “slash and char,” something very distinct from slash and burn. In this process the seasonal crop residue was not burned, but charred and turned into the earth. Doing this sequestered most of the carbon in the crop residue, and created an extremely hospitable amendment to the otherwise thin and fragile soil – something that in turn nurtured beneficial microorganisms that broke down the poor native soil and transformed it in to extraordinarily rich humus. Read this from “1491″:

“Landscape” in this case is meant exactly—Amazonian Indians literally created the ground beneath their feet. According to William I. Woods, a soil geographer at Southern Illinois University, ecologists’ claims about terrible Amazonian land were based on very little data. In the late 1990s Woods and others began careful measurements in the lower Amazon. They indeed found lots of inhospitable terrain. But they also discovered swaths of terra preta—rich, fertile “black earth” that anthropologists increasingly believe was created by human beings.

Terra preta, Woods guesses, covers at least 10 percent of Amazonia, an area the size of France. It has amazing properties, he says. Tropical rain doesn’t leach nutrients from terra preta fields; instead the soil, so to speak, fights back. Not far from Painted Rock Cave is a 300-acre area with a two-foot layer of terra preta quarried by locals for potting soil. The bottom third of the layer is never removed, workers there explain, because over time it will re-create the original soil layer in its initial thickness. The reason, scientists suspect, is that terra preta is generated by a special suite of microorganisms that resists depletion. Apparently at some threshold level … dark earth attains the capacity to perpetuate—even regenerate itself—thus behaving more like a living ‘super’-organism than an inert material.

In as yet unpublished research the archaeologists Eduardo Neves, of the University of São Paulo; Michael Heckenberger, of the University of Florida; and their colleagues examined terra preta in the upper Xingu, a huge southern tributary of the Amazon. Not all Xingu cultures left behind this living earth, they discovered. But the ones that did generated it rapidly—suggesting to Woods that terra preta was created deliberately. In a process reminiscent of dropping microorganism-rich starter into plain dough to create sourdough bread, Amazonian peoples, he believes, inoculated bad soil with a transforming bacterial charge. Not every group of Indians there did this, but quite a few did, and over an extended period of time.”

If rich topsoil was literally engineered by humans on this scale, this is an encouraging possibility to address the today’s challenges of depleted soils and desertification. Organizations have sprung up to study the potential of employing similar techniques today, creating what is now referred to as biochar (or agrichar), such as the International Biochar Initiative. And the notion that Native Americans manipulated and nurtured the ecosystems of the Amazon over 500 years ago also challenges today’s conventional definitions of what is pristine – indeed by taking away one of our most reliable archetypes of living without a footprint – perhaps shakes the whole idea of pristine wilderness to its roots. And needless to say, if carbon sequestration is truly an imperative for our species, creating biochar could hold more potential – and side benefits – than virtually any other scheme.

14 Responses to “Amazonian Terra Preta”
  1. Lou Gold says:

    Terra preta is an excellent strategy for saving the world AND saving the rainforest. I’ve been watching this from Brazil which offers the perfect example.

    The huge agricultural conversion of the Brazilian tropical cerrado (savanna)and Amazon forest to cropland across the past few decades was triggered by the development of new tropical hybrids. The impact has been immense.

    The new cropland often replaces degraded land used for grazing cattle and survial farming. But this only pushes the ranchers, loggers and rural poor toward more burning and deforestation. And the expanding worldwide demand for ethanol is now generating range wars in the Amazon.

    Terra preta can help reduce these pressures in two ways — 1) by increasing crop yields on existing land the need to plant new land is proportionately reduced and 2) shifting from “slash and burn” to “slash and char” farming by the rural poor will reduce the amount of fire and produce more food. What a deal !!!!!

    BUT, something has to give farmers an incentive to turn char into the soil rather than into (profitable) fuel. This is where the new carbon exchange enters the picture. Revision of the Kyoto protocols to include carbon sequestration in the soil can provide the needed tipping point.

  2. Ed says:

    Good stuff Lou. But I’m more worried about tropical rainforest destruction than whether or not Americans subsidize their own midwestern farmers instead of sending the money to OPEC. So are you, I would wager. Biofuel can make economic sense in the USA as long as the crop doesn’t require irrigation in a water stressed area, such as California. Biofuel can also make sense in arid regions where, as a low yield fuel crop, it stablizes soil and grows where nothing else will. But (for example) ripping out the rainforests of Borneo to plant thousands of square miles of oil palms is a catastrophe, and the idea that European carbon offsets are funding this is positively insane. And we were one of the first places to tell this simple truth, as environmentalists all over the world patted themselves on the back and looked the other way. Read

  3. Lou Gold says:

    Hi Ed, It looks like we are going to have a good discussion. I welcome the opportunity for us to learn from each other and I invite others to chime in. That’s why I am going to cross-post this comment at my own blog, VISIONSHARE at

    I want to thank Ed you for the really fine post about terra preta. It was a gem and that’s why I chose to make a lengthy and totally supportive comment. Perhaps, you can imagine my surprise at discovering, a few days later, that your post and my comments are now surrounded by large advertisements for corn ethanol?

    Your follow-up argument was “I’m more worried about tropical rainforest destruction than whether or not Americans subsidize their own midwestern farmers instead of sending the money to OPEC” sounds nice but it simply doesn’t hold up.

    The current subsidies of US corn ethanol have triggered massive deforestation in the Brazilian Amazon. When US farmers, pulled by the new subsidies, shifted from planting soybeans to corn the economic slump that has limited soybean expansion in places like the state Matto Grosso, Brazil took off — and so did the fires and deforestation which have now returned to record levels. I posted about it under the title, “US Ethanol Subsidies Help Fuel Range Wars and Fires in the Amazon”

    The fact is that we are living in a globalized world where just about everything impacts everything else. We no longer can afford the old assumptions of separation. Nowadays we are all connected.

    My specific concerns about the advertising campaign for corn ethanol are:

    1) it promotes one of the most inefficient and highly subsidized form of biofuel — corn ethanol –
    which competes with much more efficient forms such as sugarcane ethanol;

    2) it places some of the largest and most fuel guzzling vehicles in the class of new green-ness;

    3) it targets and promotes the “American dream” of big materialism and big agri-business in developing countries such as Brazil; (see my in-depth report

    4) the alliance of auto manufacturers and agri-business and oil companies has been a powerful lobby in the US Congress against sensible vehicle emissions standards and they are now greenwashing through ad campaigns like this;

    One might respond with, “what’s wrong with incremental involvement from the BIG GUYS? Aren’t they necessary in the task of changing the world?” Yes, of course they are. But the emphasis of this group is energy and not earth. They are not promoting earth-restoring technologies like terra preta and agri-char which includes a reciprocity of giving some back to the earth. At this point they are focused still on maximizing the flow of fuel in support of out-of-control energy consumption. The Chinese saying points out that crisis is a combination of danger and opportunity. For US automakers the danger is the end of cheap fossil fuels and the opportunity is biofuel. It’s all an energy trip.

    That’s the bad news. And, YES, I’m saddened that EcoWorld is serving as a vehicle to advertise it. Perhaps you might reconsider it?

    But there really is good news — can can save rainforests and save the world through the emerging carbon market and a few intelligent decisions as we revise the Kyoto Protocols. To protect the rainforests we must have carbon credits for avoided or reduced deforestion. To renew the earth and draw massive amounts CO2 down from the sky we need carbon credits for sequestration in the soil. And, yes, biofuels are part of the equation. Here’s my take on the issue:

    All best, Lou

  4. Ed says:

    Lou: You raise valid and troubling points. It is well and good that we continuously point out the tragedy of how European biodiesel subsidies have financed massive tropical rainforest destruction – especially in Asia and Africa. But only one degree of separation further is your suggestion, that Americans moving farm output from soybeans to corn reignites rainforest destruction in the Amazon to grow soybeans to fill the gap.

    EcoWorld is an advertiser supported site and our advertising inventory is available without bias to whoever wants to pay – and the vital corollary to that, which is that we will publish whatever editorial we wish, free from the influence of our advertisers. And we do.

    There are a number of things we have been quite outspoken about. Rainforest destruction, in our opinion, is far more destructive to the global climate than burning fossil fuels. The idea that we can use our biosphere to power our machines when there’s barely enough land to grow adequate food – this ought to be obvious to environmentalists, but it isn’t. This war on “anthropogenic CO2″ has ironically led to more burning and habitat destruction as automakers and oil companies (starting in Europe, by the way, how quickly we point the finger at the Americans) respond to the environmentalist lobby and offer biofuel options.

    As for building the big SUVs – it is easy to blame automakers for manufacturing them, but the real fault is with the American consumer who demands them. On the other hand, GM’s decision to launch the Chevy Volt, which is an absolute breakthrough – a series hybrid, very distinct from current hybrid technology – is courageous and unique among automakers everywhere. Hopefully people will adopt series hybrid technology – which requires an onboard gasoline generator as a range extender. There is a real chance environmentalists will successfully destroy this promising option simply because of the presence of a gasoline engine, even though it will be ultra-clean and will rarely operate. The Volt has a 640 mile range using gasoline, but most of the time for short trips which are the bulk of transportation miles, it runs on electricity.

    What do you think? Where should we get energy? Are you saying gasoline is better than biofuel? Because that’s exactly what I’m saying, and I think environmentalists have pushed automakers into a corner and are far more to blame than automakers for lobbying us into this reality of biofueled incineration of our rainforests.

  5. Lou Gold says:

    Hi Ed,

    Thanks for the lengthy response. I’m going to take the liberty of posting it at my blog as well. I’ve got a somewhat rushed day here and will have to get back to writing my response later.


  6. Lou Gold says:

    Hi Ed,

    Here’s my response.

    I’m aware that EcoWorld is an advertiser supported site and I hope no one thinks that I was accusing you of being an industry shill or something like that. Actually I noticed that the same GM ad is in the rotation of google ads over at Mongabay which is an impeccable rainforest information service. The only unusual thing at EcoWorld is that the ad has been appearing 4 and 5 times on a single page. So I concluded that GM, with the assistance of info age algorithms was conducting a targeted campaign. This is the power of modern advertising. I only wish that the terra preta and agrichar folks might be able to do the same.

    I can’t buy into your notion that the fault for building the big SUVs lies with the consumer. American industry was the default leader carrying the world into the realm of high power consuming. It converted it’s WWII war machine into a peacetime economy based on SHOPPING. Today consumer spending is 70% of the US economy. That’s why Bush, in his first post-911 press conference told Americans to “keep shopping.” This incredible habit was made possible and set into place by cheap energy. Now, half the world is standing in line wanting to acquire the American “standard of living.” Do think it’s possible? Is this the amount of energy you are looking for when you say, “Where should we get energy?”

    I think that in the short term we will have to have some mix of a bio- and fossil-fueled economy. I also believe that the mechanism that might hold consumption in check is the rising cost of energy. Yes, biofuel can be incredibly damaging — even more than fossil fuels — IF the objective is to produce cheapest cleanest energy. This can be accomplished ONLY by ripping off the earth badly.

    BUT — and I can not overemphasize how important this BUT is — if we refocus from maximizing for energy production to re-balancing for earth restoration we will change the whole equation. We need now to do three things: 1) greatly reduce the release of already stored carbon — that’s coal buried in the ground and forests on top of the ground; 2) fast retrieval of CO2 from the atmosphere accomplished through more and faster growing vegetation; 3) long-term sequestration of the captured carbon by sequestering inert non-decaying char in the soil.

    The miracle of Terra Preta is that it offers an opportunity to do all of the above. What a deal!

    But it is necessary to somehow pay for lost opportunities for quick profit through cheap logging or cheap energy. This is where the carbon sequestration definitions can provide the difference that makes the difference. Offering credits for avoided deforestation and for carbon sequestered in the soil will usher in a new carbon economy that will move us from the politics of scarcity into a new era of abundance.

    Please think about it.

  7. Ed Ring says:

    Lou: You wrote “This is where the carbon sequestration definitions can provide the difference that makes the difference.”

    I could not possibly agree more with that statement.

  8. Lou Gold says:


    Ethanol Craze Cools as Doubts Multiply
    By Lauren Etter
    The Wall Street Journal

    Is this the reason for the ad blitz ?????

  9. Jeongha Kim says:

    After reading this post, I became really interested in applying this technology (if I may say) to a patch of cropfield at my house located in a mountainous area. Is there any way I can try it at home?

    btw, the discussion is also very interesting and engaging. I have a lot of questions popping up as I read each post, and I’ll post them soon.

  10. Lou Gold says:

    Hello Jeongha Kim,

    There’s now a global movement of people getting involved in terra preta and it’s emerging ancient/future technologies. There’s a fine terra preta website that does a really fine job of pulling together all the information, questions and dicussions:

    You might want to join the discussion list which is VERY open, friendly and informative. It began as an exchange for technical information but it is expanding to include people at all levels. I personally have no background in soil science, gardening or farming. I’m an environmental storyteller and a forest defender. Indeed, I’m very new to the idea that humans and nature might develop a new level
    of harmony. I found this discussion list very helpful. You can sign up for it at

    Hope this helps,


  11. Michael Angel says:

    Please also see hypography Boards discussion site for help advice and info.

    And bioenergy lists electronic “library” of articles on TP.

  12. Akil says:

    I am very happy I found your blog on facebook. Thank you for the sensible critique. Me and my wife were just preparing to do some research about this. I am happy to see such good information being shared for free out there.
    Best wishes,
    Dorn from Winston-Salem city

  1. [...] Terra Preta Data bases, Web Sites, Mail List and Blogs – Today, 02:00 AM EcoWorld – The Global Environmental Community – Nature and Technology in Harmony A number of comments by lou [...]

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