Terra Preta literally “black soil”: in Portuguese is a type of very dark, fertile artificial (anthropogenic) soil found in the Amazon Basin. It is also known as “Amazonian dark earth” … Wikipedia
What makes Terra Preta notable is that it is fertile, anthropogenic (caused by humans), and is self-sustaining in a land where the soil is remarkably barren and where the people appear to be a throwback to an ancient civilization.
In our race for progress we humans have made enormous strides in education, sciences and technology; we have also lost much. We have lost the intuitive native wisdom of those who came before us. Paradoxically our advancement brings us to a new frontier: the scientifically inexplicable or put another way, secrets of ancient civilizations, secrets that we want to rediscover. The Amazon is a treasure trove of such inexplicables, the Terra Preta being one and how did we stumble upon it?
In 1542, while exploring the Amazon Basin near Ecuador in search of El Dorado, Spanish Conquistador Francisco de Orellana began checking around one of the Amazon’s largest rivers, the Rio Negro. While he never found the legendary City of Gold, upon his return to Spain, Orellana reported that the jungle area held an ancient civilization, a farming people, many villages and even massive, walled cities. Later on, people tried to discover Orellana’s findings but could not find the civilization.
Ultimately the El Dorado story was debunked as a myth but the notion of a complex ancient civilization persisted. In 2014 the BBC filmed a documentary on the “Secret of the El Dorado” which centered on archaeological explorations conducted by Dr. Clark Erickson. Dr. Erickson’s explorations discovered evidence that Orellana was correct in his observations that an advanced civilization was flourishing along the Amazon in the 1540s.
It is believed that the civilization was later devastated by the spread of diseases such as smallpox which happened when European people began to settle in the Americas. The big question was “How did people in Amazon have an advanced civilization since 2500 (some claim over 5000) years ago?” The answer is in their farming soil, Terra Preta.
Terra Preta, meaning “Black Earth” in Portuguese, is a soil building technique developed by ancient Amazonian civilizations. Today the Amazon rainforest is under threat as never before. Millions of acres have been wiped out. Every year farmers continue to slash and burn their way across the jungle in a largely futile attempt to turn it into farmland. This traditional slash and burn practice yields a type of nomadic farming that can sustain crop production for only a few, mostly two, years at most; while Terra Preta has the ability to maintain nutrient levels over hundreds of years.
We have yet to figure out exactly how ancient civilizations produced Terra Preta, but what we do know is that the soils contain high amounts of char-wood (bio-char). Char-wood is basically a form of charcoal produced by burning wood or agricultural residues in an environment very low in oxygen.
Terra Preta has a high carbon content of up to 150 g C/kg soil while the surrounding soil has only 20-30 g C/kg. Additionally, Terra Preta soil is enriched in organic matter as deep as 1-2m while the average norm is 40-50cm. Therefore, the total carbon stored in these soils can be one order of magnitude higher than it is in the adjacent soils.
This organic matter content is persistent even after hundreds of years of total neglect and abandonment. The mysterious Terra Preta can be found throughout Amazonia. Through plot work, researchers claim the soil can increase yields 350 percent over adjacent soils. In 2001 scientists reported that the Terra Preta in one location was under continuous cultivation without fertilization for over 40 years!
In experimental plots, adding a combination of charcoal and fertilizer into the rainforest soil, scientists recorded an 880% (~9 times!) increase in yields compared with fertilizer alone. The native Indians of the region create charcoal and incorporate it in small plots of land from 1 – 80 hectares in size.
Overall, there is probably about 155,000 km2 of Terra Preta in the Amazon, composing about 3.2% of the basin’s total area. Local farmers testify,
“The soil is easy to work and very fertile. Whatever you plant in Terra Preta does exceptionally well.”
The prehistoric Amazonians transformed the world’s worst soil into the best. If properly done, the Terra Preta will revolutionize the world agriculture in the future. Never underestimate the Ancient wisdom of Amazon, the intuitive civilization.