[Terrapreta] Earthen Kiln Conjecture

[Robert Klein]

Iam reposting to my blog 
http://globalwarming-arclein.blogspot.com/ this article by David Bennet with Lehmann on Terra Preta in2005.  This reconfirms the most criticalinformation as well as describes the original scope of the Indian civilizationitself.Againthis lays out the limiting factors and fully supports my earthen kilnconjecture. Firstly,the maize or corn exists in an environment that mitigated against its use forpurely food production.  There werealternatives far better suited. to the non terra preta environment, startingimmediately with manioc which is a rainforest friendly plant.Secondly,the only viable source of meat protein to these peoples at this populationdensity was through fish.  Withoutconfirmation, a pond with tilapia makes great sense. The waste from the dailymeal could be readily folded into any growing seed hill.  Human waste could simply have been buried inthe field itself avoiding any storage. 
This is common practice to this day.Themaking of the earthen kiln is no more difficult than uprooting the dehydratedcorn stalks and properly stacking them to form an earthen walled kiln with awall thickness of two to three root pads and an interior of tightly packed cornstalks.  Obviously, any other plantmaterial, including wood can be built into the stack as available.  The earthen wall nicely restricts air flowduring the burn phase and lends itself to optimization by changing thethickness.  It also minimizes the amountof human effort needed which is through the roof if you are attempting to covera pile of stubble or branches.Thisgives you a kiln with vertical earthen walls and a possibly domed top that canbe easily covered with earth.  Again,field trials will optimize this protocol very easily.  The kiln could be squared of or perhaps even circularthough unlikely. The only tool to this point is a strong back or two.  We have gathered several tons of
 corn stoverover perhaps an acre of land with only a little more effort than that requiredto clear the field and burn the waste.Nowwe must fire the kiln.  The easy way isto take a clay lined old basket and fill it up with coals from a woodfire.  Carry this ember charge to thecenter of the kiln top and tip the charge onto the exposed center and place thebasket as a cap to the newly forming chimney. 
More clay may be necessary to widen the chimney cap.  Throw more earth on top of this to preventbreakout of the fire.  Keep growing earthon any breakout points that start.  Thechimney will serve to burn all the volatiles produced as the hot zone expandsto fill the collapsing kiln until they are exhausted.  Thereupon the hot zone will cool off leavinga blend of biochar, ash and earth and some root ends for the next kiln.  And yes, we should have a lot of fired clay.Thebiochar itself will be a range of nonvolatile combustion products that willrange from even dried vegetation to activated charcoal following a nice bellcurve.  The material can be then gatheredin baskets and redistributed into the field onto the seed hills again reducingwastage and effort.Irealized originally that the only ancient plant that could accommodate a highenough volume of terra preta production was good old maize.  It just seemed an unlikely option fortropical rainforests. That is
 when I started looking for references to thepollen record.  The article by DavidBennett and Lehmann is one of those reverences that then emerged..Iwould like to get a full spectrum of the pollen profile since it seems verylikely that while the fence rows held the food trees, it seems more likely thatthey also used a variation of the three sisters using some form of convenientlegume.  Squashes also, of course, butnot nearly as important.Thekey point of all this is that a family can convert a field into terra preta inone short season, allowing them to repeat the process thereafter as necessaryuntil the field is completely transformed to depth.  Today, we can do the same thing using shovelsand a garbage can lid.   Terra preta: unearthing an agriculturalgoldmineNov 14, 2005 10:36 AM, By David Bennett

 
Many soil scientists insist an ancient Amerindian agrarian society will soon
make a huge impact on the modern world. They say once the intricacies and
formulation of the society’s “terra preta” (dark earth) is unlocked, the
benefits will help stop environmental degradation and bring fertility to
depleted soils. Developing and developed nations will benefit.


Orellana


The story goes that in 1542, while exploring the Amazon Basin near Ecuador
in search of El Dorado, Spanish conquistador Francisco de Orellana began
checking the area 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 the jungle area held an ancient civilization — a farming
people, many villages and even massive, walled cities.


Later explorers and missionaries were unable to confirm Orellana’s reports.
They said the cities weren’t there and only hunter-gatherer tribes roamed the
jungles. Orellana’s claims were dismissed as myth.


Scientists who later considered Orellana’s claims agreed with the negative
assessments. The key problem, they said, was large societies need much food,
something Amazonia’s poor soils are simply incapable of producing. And without
agriculture, large groups of people are unable to escape a nomadic existence,
much less build cities.


Dark earth


More recently, though, Orellana’s supposed myths have evolved into distinct
possibilities. The key part of the puzzle has to do with terra preta.
It turns out that vast patches of the mysterious, richly fertile, man-made
soil can be found throughout Amazonia. Through plot work, researchers claim
terra preta can increase yields 350 percent over adjacent, nutrient-leached
soils.


Many well-respected researchers now say terra preta, most of it still hidden
under jungle canopy, could have sustained large, agronomic societies throughout
Brazil and neighboring countries.


Amazing properties


The properties of terra preta are amazing. Even thousands of years after
creation, the soil remains fertile without need for any added fertilizer. For
those living in Amazonia, terra preta is increasingly sought out as a
commodity. Truckloads of the dark earth are often carted off and sold like
potting soil.


Chock-full of charcoal, the soil is often several meters deep. It holds
nutrients extremely well and seems to contain a microbial mix especially suited
to agriculture.


Thus far, despite great effort, scientists have been unable to duplicate
production of the soil. If researchers can ever uncover the Amerindians’ terra
preta cocktail recipe, it will help stop the environmentally devastating
practice of slash-and-burn agriculture in the Amazon jungle. Terra preta’s
benefits will also be exported across the globe.


However, even without unlocking all of the soil’s secrets, things learned in
the study of it are already being brought to row-crop fields.
Among researchers studying terra preta is Johannes Lehmann, a soil fertilitymanagement expert and soil biogeochemistry professor at Cornell University.Lehmann, who recently spoke with Delta Farm Press, says things learnedfrom terra preta will help farmers with agricultural run-off, sustainedfertility and input costs. Among his comments:


On how Lehmann came to terra preta research…


“I spent three years living and working in degraded Amazonia field sites.
Inevitably, if you work in the central Amazon, you come across terra preta.
“The visual impact of these soils is amazing. Usually, the soils there are
yellow-whitish colored with very little humus. But the terra preta is often 1
or 2 meters deep with rich, dark color. It’s unmistakable. We know terra preta
are preferentially cropped.”


On the various properties of terra preta and its modes of action…


“There are a few factors that contribute to this fertility — sustainable fertility.
Remember, these are soils that were created 1,000 to 5,000 years ago and were
abandoned hundreds or thousands of years ago. Yet, over all those hundreds of
years, the soils retain their high fertility in an environment with high
decomposition, humidity and temperatures. In this environment, according to
text books, this soil shouldn’t exist.


“That alone is fascinating for us.


“Among the most important properties are high nutrient concentrations
(especially for calcium and phosphorus). Most likely, this is linked to a
unique utilization of agricultural and fishery waste products.


“We believe that fish residues are an important portion of the high
phosphorus concentrations. Phosphorus is really the number one limiting
nutrient in the central Amazon.


“Another interesting aspect of terra preta’s high fertility is the char
(charcoal) content of the soil. This was deliberately put into the soil by the
Indians and doesn’t only create a higher organic matter — and therefore higher
fertility through better nutrient-retention capacity — but this special type of
carbon is more efficient in creating these properties.


“You can have the same amount of carbon in terra preta and adjacent soils
and the infertile soil won’t change. Terra preta’s abilities don’t just rely on
more carbon, but the fact that its char and humus is somehow more efficient in
creating beneficial properties. That’s the truly unique aspect.”
Having lived in the Amazon and studied it, how much terra preta does
Lehmann believe there is?


“There are no precise numbers of how much terra preta there is (in
Amazonia). No one has done any large-scale investigation of that. It’s very
difficult to find out in the Amazon’s jungle environment. Suitable
remote-sensing techniques haven’t yet been used.


“So (the 10 percent) estimates sometimes cited are crude extrapolations from
the few areas we’re familiar with. But we know that in familiar areas there are
huge patches of terra preta. These are hundreds of hectares large. When there
have been maps produced of areas containing terra preta — say an area around a
stream — patches are everywhere.


“It is also true that terra preta is widespread. Almost anywhere in the
central Amazon, you can step out of the car and ask a local ‘Is there any terra
preta around?’ and they’ll show you. It’s everywhere.”


What were the Indians growing? Tree crops? Row crops?


“There has been some pollen analysis. It suggests manioc and maize were
being grown 2,000 to 3,000 years ago. In the pollen bank, these crops didn’t
pop up sporadically but in large numbers.


“But all kinds of crops were grown by the Indians. Palm trees,
under-story fruit trees, Brazil nut trees — all were very important.”


On the differences between slash-and-burn and slash-and-char agriculture…


“We have very good indications that the Amerindian populations couldn’t have
practiced slash-and-burn and created these soils.


“It’s also highly unlikely that a population relying on stone axes would
have practiced slash-and-burn anyway. The normal soils are so poor that with a
single slash-and-burn event, you can only crop without fertilizer for two years
at most. Then the soil has to be left fallow again.


“Primary forest trees have a diameter of 2 or 3 meters. If all you had was a
stone ax in your hand, you’d find a different way to deal with agriculture than
felling these huge trees every two years.


“The difference between (the two systems) is the slash-and-char wouldn’t
burn in an open fire. Charcoal would be produced under partial exclusion of
oxygen. We envision that happening by natives covering up piled up logs with
dirt and straw. These charcoal-making systems are still being used around the
world.”


How close are researchers to duplicating terra preta?


“We’re working intensively. We don’t need to take any terra preta anywhere.
What we want to do is become knowledgeable about how terra preta was created
and then create it elsewhere with local resources.


“Research on this is ongoing in Columbia, in Kenya. I have research
colleagues in Japan and Indonesia also working on this. At the moment, there is
a lot of excitement but there’s a lot of work to do.”


How terra preta could help industrialized countries…


“We envision systems based on some of the principles of terra preta. And
this isn’t just for tropical agriculture. This could be very important for U.S.
agriculture.


“Terra Preta could mean a reduction in environmental pollution. What works
as a retaining mechanism in Amazonia could work in the United States where
there are concerns of phosphates and nitrates entering groundwater and streams.
We have only begun to realize the potential of how this could reduce pollution
in industrialized countries.


“Luckily the principles of creating bio-char soils will be very similar no
matter what area of the world you’re in. Results obtained in Brazil will be
pertinent for the United States.


“In terms of widespread adoption, it’s still some way away. There are still
knowledge gaps. For instance, we know there are important differences in the
effects of bio-char on soil fertility depending on what material you use and
what temperature and under what conditions the char is produced. That’s
something we should be able to resolve within a year or two. Once that’s done,
we can take the systems to Extension Services around the world and make larger
scale, on-farm research plots.


“We’re already working with dozens of Kenyan farmers on this. The project
only began this year. By next year, we hope to have a better idea of how this
works on farms.”


Where will the bio-char come from?


“Perhaps agricultural and forestry waste products could be the answer.


“Something else that gets us very excited is a link to energy production
systems (utilizing) pyrolysis...


“Really, pyrolysis is a just a complicated word for making charcoal.
Prototypes of this system for commercial power plants have been developed.
These create bio-oil, hydrogen and other co-products — including bio-char —
from the production of charcoal.


“We want to gain a better understanding of what effects this bio-char has on
soil functions. It should be quite similar to a bio-char produced in a kiln or
field. Such a system will be an entry point for large-scale production and use.


“There are competing uses for the power plant byproducts. Currently, power
plants either use the byproducts for their own energy needs or they sell it to
be used as charcoal briquettes.


“It could become profitable as soon as some of the environmental effects —
currently external — are internalized. For instance, cleaner streams, cleaner
groundwater, carbon sequestration and other things.”


For more information, visit
www.css.cornell.edu/faculty/lehmann/terra_preta/TerraPretahome.htm
 



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