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Smoldered-Earth Policy: Created By Ancient Amazonian Natives, Fertile, Dark Soils. . .
Science News ^ | 3-5-2006 | Ben Harder

Posted on 03/05/2006 3:53:54 PM PST by blam

Week of March 4, 2006; Vol. 169, No. 9 , p. 133

Smoldered-Earth Policy: Created by ancient Amazonian natives, fertile, dark soils retain abundant carbon

Ben Harder

Shortly after the U.S. Civil War, a research expedition encountered a group of Confederate expatriates living in Brazil. The refugees had quickly taken to growing sugarcane on plots of earth that were darker and more fertile than the surrounding soil, Cornell University's Charles Hartt noted in the 1870s.

The same dark earth, terra preta in Portuguese, is now attracting renewed scientific attention for its high productivity, mysterious past, and capacity to store carbon. Researchers on Feb. 18 at the annual meeting of the American Association for the Advancement of Science in St. Louis presented evidence that new production of the fertile soil could aid agriculture and limit global greenhouse-gas emissions.

Prehistoric farmers created dark earth, perhaps intentionally, when they worked charcoal and nutrient-rich debris into Amazonian soils, which are naturally poor at holding nutrients. The amendments produced "better nutrient retention and soil fertility," says soil scientist Johannes Lehmann of Cornell.

Charcoal forms when organic matter smolders, or burns at low temperatures and with limited oxygen. Nutrients such as phosphorus and potassium readily adhere to charcoal, and the combination creates a good habitat for microorganisms. The soil microbes transform the materials into dark earth, says geographer William I. Woods of the University of Kansas in Lawrence.

If some of today's Amazonian farmers were to use smoldering fires to produce dark earth rather than clear fields with common slash-and-burn methods, they "would not only dramatically improve soil and increase crop production but also could provide a long-term sink for atmospheric carbon dioxide," says Lehmann.

Slash-and-burn land clearing releases about 97 percent of the carbon that's in vegetation. Smoldering the same fuel to form charcoal releases only about 50 percent of the original carbon, Lehmann previously reported. The rest of that carbon remains in dark earth for centuries.

However, dark earth requires extra nutrients, such as those in compost. International agreements on greenhouse gases don't provide financial incentives for farmers to make the effort to create dark earth, Woods says.

Nevertheless, ongoing field experiments in Brazil suggest that the fertility associated with terra preta could provide its own incentive, reports Beáta Madari of the Brazilian Agricultural Research Corporation in Rio de Janeiro.

Brazil contains a wide range of dark earths with varying compositions. The scientists found differences between the soils used for ancient backyard gardens, which received more nutrients, and soils from distant fields.

Farmers of the time "certainly would have immediately learned about the properties of that soil, however [it] formed," says anthropologist Michael J. Heckenberger of the University of Florida in Gainesville. But the knowledge about how to make dark earth disappeared after contact with Europeans decimated the indigenous population.

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TOPICS: News/Current Events
KEYWORDS: abundant; agriculture; amazonian; ancient; animalhusbandry; carbon; created; dark; dietandcuisine; earth; fertile; godsgravesglyphs; huntergatherers; natives; policy; retain; smoldered; soils

1 posted on 03/05/2006 3:53:58 PM PST by blam
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To: SunkenCiv

GGG Ping.

2 posted on 03/05/2006 3:54:32 PM PST by blam
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To: blam
Rainforest Researchers Hit Pay Dirt (Farming 11K Years Ago In South America)
3 posted on 03/05/2006 4:03:19 PM PST by blam
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To: blam

bookmark for later printing

4 posted on 03/05/2006 4:54:56 PM PST by IrishCatholic (No local communist or socialist party chapter? Join the Democrats, it's the same thing.)
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To: blam; FairOpinion; Ernest_at_the_Beach; StayAt HomeMother; 24Karet; 3AngelaD; asp1; ...
Thanks Blam.

To all -- please ping me to other topics which are appropriate for the GGG list. Thanks.
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5 posted on 03/05/2006 9:57:56 PM PST by SunkenCiv (Fiction has to make sense, unless it's part of the Dhimmicrat agenda and its supporting myth.)
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To: blam

later read.

6 posted on 03/05/2006 9:59:57 PM PST by little jeremiah (Education without values, as useful as it is, seems rather to make man a more clever devil. CS.Lewis)
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To: blam

Bump for later read

7 posted on 03/05/2006 10:27:31 PM PST by Dustbunny
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To: blam

There was a fair bit of discussion on the dark earth topic not long ago on the FR post "Reproducing Amazon's black soil could bolster fertility...", around 2/19/06.

8 posted on 03/06/2006 2:13:48 AM PST by gleeaikin (Question Authority)
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· join list or digest · view topics · view or post blog · bookmark · post a topic · subscribe ·

Just updating the GGG info, not sending a general distribution.

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GGG managers are SunkenCiv, StayAt HomeMother, and Ernest_at_the_Beach

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9 posted on 05/25/2010 7:27:29 PM PDT by SunkenCiv ("Fools learn from experience. I prefer to learn from the experience of others." -- Otto von Bismarck)
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