Terra Preta

Posted by Sustainable OKC | Posted in Books, Compost, Ron Ferrell, Science, Soil Management | Posted on 02-03-2009


by Ron Ferrell

Just how clever were those South American Indians? They were one of the first races on the planet to include the number 0 in their mathematical and monetary system, but now their population cannot be found in any resemblance to what the anthropologists say once flourished. It was thought that they overused their food infrastructure, but most likely the few who were left after war and disease brought by the Spanish invaders decimated their numbers were absorbed into other tribes in the area.

After years of archaeological research an unlikely native asset revealed itself. The research revealed a vast area of black soil that the natives had apparently created and used to maintain enormous cultures with fruit and food–an oasis in the jungles. Research indicates the key ingredient that fueled this composting marvel was charcoal. It appears that making charcoal was an intentional industry to help create the black Terra Preta.

Dr. Michael P. Byron states, in his book The Path Through Infinity’s Rainbow:

Terra preta soil is formed by incorporating biochar–locally produced charcoal–into ordinary soil. This activates the soil and enables it to permanently hold far greater quantities of minerals and nutrients than would otherwise be possible. This then sets into motion a complex and still not fully understood chain of events that include microorganism growths throughout the soil, which results in the soil becoming terra preta soil within several years.

This remarkable soil is found in abundance in the black earth were pottery shards and remnants, mixed in with other organic matter to create possibly the richest mass of intentional earth on the planet. Even National Geographic reports that terra preta is not to be found anywhere else on earth. 

In the September 2008 issue of National Geographic, "Where Food Begins," maps and illustrations of terra preta vs. normal soil are depicted from the central region of South America. (Can't find a link for the graphics, but they are on page 9293 of the magazine.)

Another thing about these illustrations that struck me is higher on the same map. The "fertility" chart graphics indicate a strip through the central United States that is rated as ‘highly fertile.’ It appears to me that the highly fertile area includes Oklahoma. A large area of unusually deep top soil is just north of us, in Kansas. This is great news for anyone trying to raise a garden in this part of the country. This may explain why folks living in southeastern Oklahoma are able to raise such prolific crops.

The latest issue of Mother Earth News also has an article of the ‘ancient’ soil building technique. They renamed it ‘char,’ but it apparently works as nutrients bond to charcoal for nutritional longevity.

So throw a dart and live where you will, but the aforementioned map indicates to me, that if you are truly interested in food growing potential, the central United States is the place to be. Tornados for sure, but no pesky hurricanes, desert or higher than average drought predictions.

With all the solid information and resources for making your own wonderful compost, soil enrichment is preferable to soil building any day of the week. I’m blessed with sandy loamy soil, so weed control and soil amendment are my main goals in building my garden spot.

Go here to find a contemporary recipe for Terra Preta. Mix up a batch and invite me over.