Estado da Arte das Terras Pretas de Índio no Âmbito Mundial (; Christoph Steiner ‐
University of Georgia, Athens GA. USA; William Woods – University of Kansas –
Lawrence, KS, USA)
I am very grateful for this the opportunity to be here, to learn about Terra Preta and to see Terra Preta again. With our presentation we want to summarize The history of Terra Preta and and also charcaol research, current materail flow management and what we could learn from the past (if such a learning process exists?)
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The Reference Soil Group of the Anthrosols holds soils that were formed or profoundly modified through human activities such as addition of organic materials or household wastes, irrigation or cultivation.
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Nutrient and organic rich anthropogenic soils are found throughout the world. A notable and well studied example are the plaggen of NW Europe. They were created by mixing cut turf or sod (the upper layer of soil mixed with grasses and their roots), stable wastes, garbage, ash and char, and seaweed, where available. This slide shows a map of the southern range of plaggen. Plaggen or “built soils” are also found in Norway, the United Kingdom, Ireland, and as far north as the Faroe Islands. Please substitute the slide of the woman in the soil pit for the one of the green expanse. She is a graduate student at Wageningen and we were out examining plaggen at the edge of that city. As a result of human occupation, enormous areas of the planet have been modified by a variety of mechanisms leading to the redistribution and alteration of earthen and other surficial materials . The slide shows plaggen on the island of Papa Stour in the Shetland Islands accumulated from the early Medieval Period into the 20th century. A Papa Stour plaggen profile and an lowland expanse of plaggen. The stony area in the upper portion of the photo shows an upland area where peat had been cut for fuel. The resulting ashes and char were added to the garden.
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Amazonia is no exception, signs of human alterations of the landscape are obvious in the Beni.
These photographs show ridged fields, fish ponds, canals and causeways, and huge anthropogenic habitation mounds. These extend over 1,000 of square kilometers of the Bene region of Amazonian Bolivia.
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Maybe one of the most interesting Anthrosols is Terra Preta, because they probably show the most pronounced alteration in soil quality. They prove both, that long‐lasting carbon and nutrient enrichment is possible in the humid Tropics. Hortic Anthrosols are associated with virtually any Reference Soil Group
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Francisco de Orellana is probably the first observer of Terra Preta and probably the only foreign witness of the existence of large cities. 6
Both Hartt and his assistant Herbert H. Smith (1851‐1919) in his book Brazil: The Amazons and the Coast (1879a) and in an article “An American Home on the Amazons” (1879b) clearly made the connection between the dark earths and prior Indian villages. They recognized the human origin and described Terra Preta as rich soil originated from the refuse of a thousand kitchens for maybe a thousand of years. 7
C. Barrington Brown (1839–1917) and William Lidstone made similar observations, recognized the artificial origin and were apparently the first to use the term terra preta (“terras pretas”) in print. “In two places also, in the forest, were the sites of ancient villages, marked by a deep black soil
mixed with broken pottery”
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“undoubtedly of artificial origin ...highly prized as agricultural grounds, owing to their fertility; and they
bear the name of “Terras pretas”. The illustrations are from the book “Fifteen Thousand Miles on the Amazon and its Tributaries”
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“the spot, like that on many other elevations bordering the Amazon and its branches, was the
favorite dwelling-place of Indians in bygone days; …”
“Villages must have stood upon these spots for ages, to have accumulated such a depth of soil
about them; and probably their original founders were of a race that has now completely
vanished.”
Guess which city is pictured in the right corner?
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Friedrich Katzer's (1861‐1925) classic volume on the geology of the Amazon region was published in Leipzig. Based on his three years of fieldwork (1895‐1898), Katzer
(1903:64‐70) recognized the fertility of these soils, conducted pioneering analytical work on these soils, and as a result concluded that they had a completely different origin from the Chernozems he knew in central Europe in that the former were cultural in origin. He found that these soils consisted of an intimate blending of mineral residuum, charred plant materials, and decomposed organics. He found high organic matter content, in contrast to soils from surrounding locations. Based on his analyses, Katzer suggested that because of their fertility the dark earths were cultivated in ancient times when the region was more or less densely populated. His would be the last published chemical analyses of dark earths until Sombroek in 1966.
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Katzer compared Terra Preta with Chernozems and was right that they are of different origin. But one thing they have in common and this is charcoal or black carbon and both are very productive soils.
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Here we can see such charcoal particles in Terra Preta. Surprisingly also the use of charcoal as soil amendment has a long history.
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The book “American Agriculture” published in 1846 describes many uses of charcoal in agriculture among
them are:
Charcoal absorbs and condenses the nutritive gases within its pores. The economy and benefit of such
applications can be readily understood, as they are continually gleaning these floating materials from the
air, and storing them up as food for plants. Charcoal as well as lime, often checks rust in wheat, and
mildew in other crops; and in all cases mitigates their ravages, where it does not wholly prevent them.”
“Ammoniacal liquor holds large quantities of nitrogen,….charcoal dust may be added , ..the charcoal soon
combine with the ammonia, ..it is a powerful manure, and should be sparingly used.”
“Guano should be mixed with twice its bulk of charcoal dust”
“Charcoal should be added to tanks holding liquid manure to absorb the ammonia”
“ Poudrette is the name given to the human faeces after they have been mixed with charcoal dust..”
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“A dressing of charcoal has in many instances, been found so beneficial that it has been extensively
introduced in France for the wheat crop”
The turnep (Brassica rapa.) Charcoal dust applied in the same way has been found to increase the early growth from four to ten‐fold. Fences: Charring or partially burning the part of the post which is buried, will add to its duration. So also will imbedding it in ashes, lime, charcoal, or clay. Preservation of timber: Pyrolignite of iron, formed from iron dissolved in pyrolignous acid. 15
But also the resistance to decomposition was
well known in the past people made use of it by
carbonizing the outside of wooden fence posts
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Historical Biorefining (Biorefinery) , Mainly in southern Germany, Austria and western Czechia, these stones can be found distributed in the landscape. The stones were used since the 8th century to collect pitch tar, creosote or wood vinegar (pyroligneous acid). The process is similar to wood carbonization and the liquid products were (are) used as lubricant, firebrand, pharmaceuticals and for sealing (e.g. woody barrels). 17
Austria and southern Germany, tarry liquids were collected, today petroleum industry, The flat and inclined stones ("Pechölsteine", German) were grooved in order to allow flow off and collection of the liquids. Wood (preferentially resin rich pine or beech wood) is piled in the center of the stone. This pile is sealed (exclusion of oxygen) with turf (the green inside) and lit on the top at midday. Depending on size the process takes 12 to 48 hours. First the golden‐yellowish oil was collected, later the tarry pitch. Pechölbrennen pyrolisis has a long history. It seems that both the use of charcoal in agriculture as well as the production and use of
It seems that, both the use of charcoal in agriculture as well as the production and use of what we call today bio‐oil was forgotten.
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Traditionally the only way to maintain soil fertility was by maintaining and increasing the
soil organic matter content.
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Justus von Liebig discovered the mineral nutrition of plants and a century later Haber and Bosh developed ammonia syntheses. Today mineral nitrogen production consumes 3.35% of the world natural gas production, it boosted agricultural production but did not treat soil degradation caused by a loss of soil organic carbon.
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The soil C pool is 3.3 times the size of the atmospheric pool (760 Gt) and 4.5 times the size
of the biotic pool (Lal 2004, Science) and most agricultural soils have lost 60 to 75% of
their original soil organic carbon. This emissions contributed significantly to global
warming.
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Today mankind faces several global problems such as soil degradation, peak oil,
climate change. But there is also a declining supply in phosporus and the price of
nitrogen fertilizer increases with fossil energy prices. This is one reason for the
observed increases in food and fertilizer prices in 2007. Furthermore the dedication
of land to biofuels increases carbon emissions by bringing additional land into
cultivation. This highlights the value of using waste products!
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Our current nutrient and carbon management is based on the availability of cheap fossil fertilizers and are very wasteful. This images show the Mississippi flowing into the gulf of Mexico. Turing its way through the USA the water accumulated so many nutrients that it causes the so called “death zone” in the Gulf of Mexico. An area of less than 2 ppm
dissolved oxygen and covers 20,000 square kilometer. 23
Many times nutrients and carbon rich materials accumulate and are deposited in land fills. Even manures like poultry litter is sometimes deposit in land fills. 24
Charcoal was re‐discovered for two reasons, 1. carbon sequestration and 2. to enhance soil fertility. Walter Seifritz id obviously not know about agricultural benefits and Terra Preta
soils. Therefore he proposed to capture and storage of carbon in charcoal and its deposition as “Charcoal Mountains” or land fills. 25
Back to Terra Preta:
In 2001 a group of Terra Preta researchers discussed the recreation of these soils at a conference in Spain (is this right Bill?)
Wim Sombroek recognized the carbon sequestration potential of Terra Preta and questioned whether it was "economically justifiable,” to create and cultivate such soil today (p. 261). So under what conditions “Terra Preta Nova” could be economically feasible?
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In the past few years we conducted several experiments to assess the agronomic
benefits of charcoal applications
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And described Slash and Char as Alternative to Slash and Burn, aiming the recreation of Terra Preta. Although there are significant increases in productivity those increases alone might not be enough to use charcoal or what is called “biochar” today. 28
In 2002 was the first Terra Preta Nova workshop in Manaus
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At the same time the documentary “The Secret of El Dorado” was produced. This movie received a wide audience and among them were producers of biomass energy.
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They were pleased to discover a new use of a byproduct from pyrolysis which is charcoal or biochar. But this charcoal can also be used as a fuel and the fuel use does compete with its use as biochar. So still the questions: What needs to happen to make it economically feasible?
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Bioenergy with biochar carbon sequestration would enable us to produce carbon negative
energy. That
Th t means th
thatt with
ith each
h unit
it off energy produced
d
d carbon
b di
dioxide
id iis removed
d ffrom
the atmosphere as long as re-growing biomass is used. The carbon sequestration potential is
enormous on a global scale and it is obvious that the global carbon trade should facilitate
biochar carbon sequestration in agricultural soils.
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In 2004 a groundbreaking conference on charcoal was organized by a energy system developer and the University of Georgia. This conference brought energy producers and policy makers together with agricultural ecologists, soil scientists, engineers, archeologists and private‐sector companies from around the world.
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In 2006 the international biochar initiative was formed with conferences in Australia and Newcastle. The next international conference will be next year in Rio de Janeiro and in Kyoto in 2012 when the Kyoto protocol expires. If you remember the group picture taken in Spain we can notice a remarkable increase in interest and participation and I predict that Rio de Janeiro will double this number again. 34
Biochar is on the way be an acknowledged carbon sink by the United Nations. The UNCCD proposed the use of biochar as a link between the Rio conventions. However it will remain a challenge to make the carbon market accessible for small farmers in the Amazon and other regions in the world.
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