I came across this item on terra preta that adds to our knowledge while describing its importance.
The first fact that jumps out is the estimate of the soil’s distribution and scope. The fertility of this soil means that we can deduct a population base associated with this environment of possibly as high as one hundred million. Certainly a magnitude of between twenty to thirty million is very conservative. I make this conclusion based on the fact that a family can operate a five acre farm of corn and cassava, producing sufficient staple foodstuffs to support them.
The high population density, not unlike the rice fields of
South Asia, was terribly vulnerable to contagious diseases and a swift collapse would have brought the human wolves down on top of the survivors. Our own experience with the effect of such onslaughts and more importantly their swift repetition, informs us of the reasons or total disappearance of the indigenous populations.
The only survivors would have been those who took to the forest in small separated bands and avoided contact. I think that there was some remnant survival although I am at a loss to explain the lack of informants with access to the underlying knowledge.
The second fact is the idea that of leaving a layer of the terra preta soil so that it might restore itself. Nice thought, but there is no way that the char will be replicated by biological action. However, it is quite plausible that the rapid addition of new material to the soil could be stabilized by the remaining char in the soil through the normal mixing caused by biological action. The percentage of char would decline, ultimately to a minimum level.
This is an issue well worth doing a lot of research on since it tells us that the creation of terra preta will get a huge hand from Mother Nature. My suggestion of creating biochar seed hills is more beneficial than at first thought. A concentrated hill occupies only twenty five percent of the space available, yet biological mixing will possibly build up the hills and cause the zone of influence to expand rather than contract as one would at first expect.
It is also noteworthy that the suggestion was made of something called ‘slash and char’, whatever that could be. It is clear however that the source material was the crop residues as I have been stating in previous postings. Thinking that Stone Age equipped man was going to hack down trees to make biochar is ludicrous. Girdle and kill and burn down to get started are things he could do. After that he relied on his crops for feedstock.
I have already posted on the viability of using corn stover to make an earthen field kiln that produces biochar in abundance. This article simply adds detail to the picture.
It is becoming clearer that the real population of the
was far greater than we have ever guessed. Corn culture certainly supported huge populations, including large expanding populations in the Americas . Their collapse began a lot earlier than 1492. European visitors were able to make one way trips long before Mississippi Valley figured out how to return. And a boatload of your typical common cold and flu would actually decimate any population concentrations as could still happen on isolated communities. Columbus
It would not surprise me that legends of the Indians rising and destroying visiting traders before 1492 was driven by the obvious relationship between strangers and fatal disease.
Anyway, enjoy this article that quotes extensively from Charles C Mann’s article in Atlantic Monthly.
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.
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
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
Terra preta, Woods guesses, covers at least 10 percent of Amazonia, an area the size of
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
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.