The Amazon milieu

Sean at terra preta list (see link) posted the following note

Hi Robert,

You said this again, (and I questioned before whether you meant what you had posted before) ...
"As I posted a while back, the only practical way that the soils in the Amazon could have been created would have been in conjunction with the bio charring of corn stover."

Why do you think the Ancient Amazon rainforest had corn, circa 2500 B.C. or since? I think, like now, that there is far more "rainforest" fauna in that biome (i.e. big trees, in a jungle, like American Mahogany trees, etc.), rather than corn, or maze. Don't you? There surely is now. Is there any evidence that the charcoal in the Amazon is from corn stover? The native soils (without charcoal amendments) in the Amazon rain basin are Antisol and Oxisol soils. These are high in Aluminum Silicates (clays), low in carbon, and very low in organic material (humus) or plant nutrients. Corn will hardly grow in this kind of soil. It's kind of a chicken or the egg thing. Corn can't grow well until you plant it in "Terra Preta" soil - "Terra Preta" soil is made by amending soil with charcoal made from lots of corn?!

Do you have any evidence for your conjecture? Or, are you supposing that corn stover must be the only or main source of biomass used to make the charcoal in the original "Terra Preta" soils of the Ancient Amazon? Why do you suppose this?



This goes to the heart of the problem facing the originators of the terra preta soils.

1 They did not have the tools to physically handle the available biomass. We actually have limitations today. Their solution was as always to use slash and burn. The burn off of the undergrowth would also kill off the larger trees which would then rot out over the next two years or so. Remember, that this is the Amazon.

2 The ash would provide the nutrients for corn and cassava culture. Without terra Preta methods, this would be exhausted in two to three years.

3 With terra preta methods applied to the corn in particular, and a continuing burn off of the field to suppress weeds and regrowth we get the resultant soils with a modest labor input.

4 I emphasize the corn because it clearly produces the several times as much biomass as any likely crop can produce, and it lends itself to the manufacture of a biochar stack. However, any other convenient waste material that could be handled by hand would also be thrown into the stack.

5 Pollen analysis has confirmed the two principal crops of corn and cassava, which ended any uncertainty I might have had.

The problem is that the only energy available to a farm family then was their own. That is the over riding constraint that we cannot avoid.

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