Making Primitive Biochar

Those who have followed my blog know that I proposed a method for producing biochar that was plausible inside the limitations placed on an antique society living in the Amazon rainforest. Key to the time and place was the use of maize as the principal source material. That this was so was confirmed by published pollen studies and by more recent translations of sixteenth century reports from southern Brazil which described widespread maize culture.

When I began my thought experiment, the presence of maize seemed very unlikely in view of the known dynamics of rainforest soils. Yet I needed a plant that produced packable waste that could be handled without steel tools. Wood was both high cost in human energy inputs and very resistant to charring and crushing. Most other crops simply failed to produce both a crop and much biomass. No primitive farmer was going to plant a stand-alone char feedstock and lose a season.

This is where corn or maize came in. It produced a stable easy to store high volume crop that also produced perhaps ten tons per acre of corn stover. This stover was also very packable because there are no branches. What made it more attractive was the root ball which is in the form of a disc and is often very easy to pull out of the soil. Thus a field could be stripped of its ripe corn and then stripped easily of its stover.

Stacking the stalks was easily accomplished and using the root balls to form an outer wall simply a matter of paying attention. The key idea was to provide an outer shell of mud that closed off the packed stover. Now they did not have a sheet of metal foil to add another heat resistant air tight layer, so it is likely that they slathered on a thin layer of river clay to form a air tight seal. Again field experiments will inform us as to the extent that this is all necessary.

At the end of the day, without any tools, we have a thin clay dome or a mud dome enclosing ten tons of packed stover.

This is then loaded with a charge of burning coals. I have considered top down but suspect that simply feeding a charge in through the bottom perhaps along a narrow trench will be good enough. A small amount of air will be drawn to the charge maintaining the heat production and the produced heat will steadily reduce the maize very quickly. Gasses will be captured and ignite as the burn progresses steadily reducing the load.

Eventually the whole load will collapse upon which it will be smothered with more dirt.

I had originally envisaged this process taking many hours, however corn stover is like paper and merely needs to be heated for it to curl up and quickly decompose.

Ten tons or one acres production would give us three tons of biochar which is ample for that one acre, particularly if one goes the extra step of creating seed hills on only a third of the surface. In one season, you are in business. The one remaining mystery is why this method failed to make it out of the Amazon, because it would have nicely augmented the three sisters throughout the Americas. Or perhaps it did and we simply never noticed or our steel got there first and disease got there first.

Large Complex Societies in Amazon

I wrote this article earlier this year to emphasize that the actual carrying capacity of the Americas with the terra preta technology in the Amazon and the three sisters elsewhere was huge and surely compares to contemporaneous China and India.

http://globalwarming-arclein.blogspot.com/2008/02/one-hundred-million-pre-columbian.html

I have always taken the position that if it was possible then it was so and that if Archeology has not confirmed it, keep digging. Far too much weight has been given by the profession to the importance of lack of evidence when the prospective terrain is barely explored to depth.

No valley on Earth went unoccupied. The question was merely how best to make a living. If that was established, then the population grew to carrying capacity.

Before the advent of Europeans, the Americas had stable large communities that were very good at cropping their lands. That we lack a lot of evidence has more to do with the use of wood for building.

The early reports talk of large populations everywhere. Each society had ways and means to sustain their soils. Then the steel axes arrived.

The natives were able to switch to slash and burn which is initially very successful for a couple of years or more. Then fertility collapses and the lands must be abandoned. This surely led to population collapse everywhere. We already know of the ravages of foreign diseases throughout the Americas. Unexpectantly we also have a huge reduction of the ecological niche itself as former farmlands were first abandoned for virgin fields and then lost under jungle.

This report shows what the diggers are now finding.

Pre-Columbian Tribes Had BBQs, Parties on Grave Sites

Alexis Okeowo

for National Geographic News

December 05, 2008

Some pre-Hispanic cultures in South America had elaborate celebrations at their cemeteries, complete with feasting and drinking grounds much like modern barbecue pits, according to a new archaeological study.

Excavations of 12th- and-13th-century burial mounds in the highlands of Brazil and Argentina revealed numerous earthen ovens. The finds suggest that the graves were also sites of regular festivals held to commemorate the death of the community's chief.

"After they buried an important person on the burial grounds, they feasted on meat that had been steamed in the earth ovens and drank maize beer," said archaeologist and study co-author José Iriarte.

Large rings of raised earth surround the mounds, with paths leading to their centers. The rings are composed of a series of the ovens, which were built up over generations.

"This monumental tradition spread across kilometers, from southern São Paulo state in Brazil to Río Grande del Sur in Argentina," added Iriarte, a professor of archaeology at the University of Exeter in the U.K.

The Jê people, who occupied the area Iriarte refers to during the 12th and 13th centuries, are recorded as having often consumed an alcoholic beverage of maize and honey.

"They carried out these festivities in a period of the year when pine nuts [eaten at celebrations] and maize were abundant," Iriarte added. "These were important resources to them."

Researchers found ceramic vessels such as bowls and small drinking cylinders that still contained residues of corn. Unidentifiable animal remains were also discovered.

The findings are published in the December issue of the journal Antiquity.

Complex Societies

Archaeologists traditionally viewed the Jeê people as small, nomadic groups. But these discoveries prove that theory wrong, Iriarte said.

"This is an unexpected development in this part of southern America," he said.

"We think we are in the presence of a sizable, regionally organized population."

Along with the ovens, the team found big subterranean houses complete with roofs in a region rich with diverse plant and animal species, a desirable place to settle down, Iriarte added.

"They were able to combine hunting and gathering, horticulture, fishing, and slash-and-burn agriculture to sustain large populations," said Iriarte, who has been conducting archaeological digs in the area for years and is considered an expert on Jê culture.

Michael Heckenberger, an archaeologist and anthropologist at the University of Florida who specializes in the Amazon, explained that the environment in southern Brazil was previously believed to be difficult for sustaining large populations.

"But I think it is very clear that [Iriarte and colleagues] have demonstrated that these were more than marginal tribes," Heckenberger said.

"This is part of a growing body of research that shows that groups of people in lowlands in Brazil had large, socially complex groupings, sociopolitical organization and social patterns including feasting," he added.

The new evidence also shows that, opposed to other peoples in the region, the Jê had settlements and celebrations that were more dynamic and permanent, Heckenberger added.

(See related: "Ancient Amazon Cities Found; Were Vast Urban Network" [August 28, 2008].)

Social Status

Other evidence has shown that the burial parties were reserved for renowned chiefs—who inherited their leadership positions—demonstrating "a moderate degree of political complexity," said Iriarte, whose work was funded in part by the National Geographic Society's Committee for Research and Exploration. (National Geographic News is owned by the National Geographic Society.)

The chief's son usually sponsored the festivities, Iriarte added. That way, "the relative reaffirmed ties to ancestors and to his position in society."

The Jê were also reaffirming their territory, according to Iriarte. Around A.D. 1000, several other groups of people were migrating around the Brazilian and Argentine highlands. The burial monuments, situated on hilltops or ridges, clearly outlined Jê communities, Iriarte said.

"They are really marking their land," he added.