Terra Preta de Indio–The mysterious soil of the Amazon (and beyond)

Manaus-Amazon-NASA.jpg     Photo courtesy of Wikimedia Commons

What if there was a soil that could increase crop yields by 800%, reproduce itself so that fertilization with chemicals was not required, and reduced pollution by pulling carbon out of the atmosphere? And what if this same soil could transform nutrient poor soil all over the globe opening areas to agriculture in food-starved regions?

There is such a soil. It is called Terra Preta and it was first uncovered in the Amazon basin in the 1870s, but not really studied until the 1950s.  At that time, two explanations were put forth.

The first theory goes like this: the soil was the natural consequence of volcanic ash, slash-and-burn farming, and garbage from ancient middens.

The problem is this:

  • This mysterious soil does not cover the  expanses implied by slash-and-burn or volcanic ash.  It is generally found in well-defined plots up to two acres. Deliberate plots, not accidental plots.
  • The soil levels are up to 9 feet deep. That is a lot of slashing-and-burning.
  • In order to make the soil, you need partially burned wood–charcoal. Ash will not do the trick.

The second theory, based in part on the information above, is that the soil was invented–created by a past civilization. When? Usual dates say 1500 BCE to 500 AD.  But this is based on known habitation dates. And, unless the civilization was built with stone, this environment is not known to preserve archeological evidence for us to discover.

So, I looked further for other opinions. I did find one web article claiming the soil is 7000 years old–but there was nothing in the article to substantiate this claim. I did a web search and found something in Google ebooks: Agroecology, Ecosystems, and Sustainability edited by Noureddine Benkeblia. It attributes the 7000 year old date to Neves (2003). I wanted to go directly to Neves, but the book’s bibliography is not available without paying $80 for the ebook, and Amazon wants almost $100 for the print edition. I tried searching for Neves (2003) in ABE and other book sellers–no luck, but I suspect it is in Portuguese.  I hate dead ends!

I did discover the Amazon basin is not the only area where this nutrient rich regenerating soil is found. In the harsh environment of Bolivia’s Llanos de Mojos there is evidence of an advanced sophisticated civilization with canals, mounds, causeways, villages, and–you guessed it–Terra Preta.

And I wasn’t really surprised to learn that Terra Preta has been found in other locations on the South American continent– Ecuador, Peru, and French Guiana.

But here is what did surprise me:

Terra Preta has also been found in Liberia, an “easy” skip across the broad Atlantic from South America, and in South African savannas.

Independent discovery? Or was it “transplanted” in cross-Atlantic voyages thousands of years ago? And if so, who taught whom? Or was there a common origin with both areas receiving the knowledge from an even older source?

Oh, and I finally found a recipe for making it: If you have a minute, check out the list of ingredients. It will make you smile!

Truth is, though, they still don’t know exactly what is in it.

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