**4. The scientific characterization of** *Terra Preta de Índio*

While archeologists, and to some extent anthropologists, were becoming more deeply involved in the discussions about the relatively high or low fertility of the Amazon region, investigations into the soil's relation to social complexity, sedentary or semi-nomadic lifestyles or population density remained secondary at best. Other scientists took up the subject of *Terra Preta* and ran with it. Soil scientists more and more gained international public interest and headlines from prestigious and highly visible publications.

In the early 1980s, research on the "natural scientific character" of the *Terras Pretas* began in earnest, with the investigations of Eije Erich Pabst and Gerhard Bechtold. They demonstrated, for the first time, that the "black earth" differed dramatically in chemical composition from the typical, reddish oxisols of Amazonia. They re-confirmed the soil's higher pH value, abundance of organic substances, and much higher nitrogen and phosphorus levels [2, 3].

How the *Terra Preta de Índio* could have come about what the leading question of Eije Erich Pabst, who not only explored the soil properties, but also ethno-pedological aspects. Pabst posited that if one could determine how the *Terra Preta* was arose from the oxisol, then one could recreate such improved soil enhancements today. As part of his strategy, Pabst visited several ethnic groups in the Amazon region. Here he found quite diverging opinions expressed, including their natural provenance by the Assurini, divine origin, as expressed by an Arawete: "the forest God threw them down from heaven," and an anthropogenic or "man-made" origin. Finally, some Waiapi natives simply explained that they just did not know how the soil came to be [3].

Despite efforts, Pabst was not able to track down a definitive indigenous "recipe" for the manufacture of *Terra Preta* during his oral interview investigations. Pabst emphasizes, however, that this knowledge once existed, but was lost in the course of the population collapse the Amazonian people suffered during and since the European colonization. The indigenous populations were largely displaced from any favorable localities and generally forced into non-sedentary modes of survival. It is stressed that this historic and unmerited loss of cultural expertise should in no way be equated with native inventive capacity, agricultural competence or claims thereof.

Whether Amazonian black earths were intentionally produced or not, continues to fuel debate. On the one hand are the positions that exclude all intentionality and assume that the *Terra Preta* resulted to the indigenous lifestyle. This was more or less the opinion of the earliest archeologists and anthropologists conducting research in the twentieth century. On the other hand, positions exist that presume a very clever technique for the deliberate production of humus, even going so far as to suggest specific ceramics were created and then used in the process [40].

Ethnopedological research has shown that there still do indeed exist Amerindian groups whose lifestyle leads directly to the production of *Terra Preta* [41]. Even without this evidence, it would seem plausible to presume that at least some of the groups formerly living in the Amazon had consciously carried out soil improvement measures by adding a combination of plant charcoal, ceramics and organic matter [42]. Considering the many innovations of the Amazon Indians [43], it is highly unlikely that such a vital adaptive measure and its life-improving results would have totally escaped the conscious awareness of the indigenous population living in Amazonia prior to the arrival of the Europeans.

Moreover, historical studies have shown in other important cases that the ahistorical perspective, that the indigenous products are results of pure happenstance, stems from the faulty view of native peoples as "children of nature"—a perspective

*Ecosystem and Biodiversity of Amazonia*

treating *Terra Preta* soils as bonafide archeological sites.

During the subsequent 10 years, Peter Paul Hilbert located, sample and excavated *Terra Preta* sites along the middle Amazon River [21]. Later, archeologists associated with the Museu Paranse Emilío Goeldi in Belém, such as Mario Simões, continued Hilbert's work and even intensified the systematic approach towards

Under Betty Meggers' intellectual supervision and financial support, Mário Simões and his assistants, located and pit-tested hundreds of *Terra Preta* sites, mostly along the Amazonian tributary rivers, such as Rio Negro, Rio Madeira and Rio Tocantins [22]. Recognizing these *Terra Preta* sites mainly as deposits of discarded refuse (kitchen middens), these archeologists were largely interested in the material cultural remains, such as fragmented ceramic vessels and some rare polished stone implements "thrown away" by their original, ancient owners.

Quantifying and classifying the ceramic fragments by their diagnostic features, such as decoration, style, technique and form of vessel, this group of researchers created a chronology-based model of site categorization and orientation. According to the dominant typological pattern of the ceramic fragments, four cultural traditions were pronounced: Zone-Hachured, Incised Rim, Polychrome and Incised-Punctuated [23]. As most of these habitation sites had a multi-compositional sequence of archeological remains, it was concluded that the ancient Amazonians had a semi-nomadic strategy of survival. This was necessitated, it was argued, by the poor soil conditions [24] which could not support extended agricultural use and therefore, neither a complex society nor a high population rate. Despite the extraordinarily high biodiversity of the Amazon region, it was claimed, the habitants had to change their settled areas periodically, which on one hand, explained the great number of *Terra Preta* sites and, on the other, their frequent reoccupation by varying archeologically displayed cultures. Betty Meggers elaborates on this paradoxical situation contrasting the Amazonian environ-

ment and archeological record with the idea of a "counterfeit paradise" [25].

complex societies, based on powerful and interrelated chiefdoms.

the origins of early crop domestication [29–35].

complexity, was again, relegated to the academic shadows.

Donald Lathrop [26], José Brochado [27] and Anna Roosevelt [28] questioned this model of environmental restraint and soil poverty, and its inherent relationship to a low level of social complexity. They defended the opposite scenario of a rich and fertile Amazonian environment, which supported a large population and

Eduardo Neves, observing a gradually waning academic interest in these debates

and marked shift away from topics involving ancient Amazonia as important research terrain, felt impelled to develop an interdisciplinary-driven and internationally-inclusive research strategy. Initially located in the lower Rio Negro and Rio Solimões region, he united a group of scientists from soil sciences, anthropology, biology, ecology, geography, geology and sociology and set out to reinvigorate the research topic of *Terra Preta*. This wave of researchers made pivotal contributions to the knowledge of Amazonian Archeology, focusing most recently on the question of

Contemporaneously, Michael Heckenberger [36], Denise Schaan [37, 38] and Denise Gomes [39] reignited discussion on the social-power relations expressed by the construction of the monumental structures of the ancient Amazonians. Their primary focus being the massive vertical constructions and their reflection of a high social and cultural complexity. Some examples include the mound builders of Marajó Island, the road builders of the Tapajos, in *Alter do Chão*, near Santarém, the village builders of the upper Rio Xingu or the geoglyph builder in Rondônia and Acre.

Despite all of these advances in the knowledge of *Terra Preta*, the subject was generally, yet again, abandoned as a serious research focus and the idea of the "dark earth" as a socio-cultural phenomenon, a massive public works project of horizontal monumentality, or as an expression of high social organization and cultural

**132**

no longer seriously tenable [44, 45]. On the contrary, it is almost certain that at least some central components of the *Terra Preta* required deliberate actions with the purpose of soil enhancement at play. The introduction of charcoal on fields and plantings could be one such element which is current in Amazonia even today, where hearth ashes are strewn on house gardens.

The discovery of the black earths has far-reaching significance for the history of the American continent, as it forces a total revision in estimating number of inhabitants in Amazonia prior to 1492. Because of the high and enduring fertility of *Terra Preta*, it now seems plausible that the area, before European invasion, would have had a population of several times the currently accepted approximate figure of one million people [46]. Currently a pre-colonial population of 8–10 million is considered quite plausible, based on estimates of the currently known acreage of Amazonia *Terra Preta* [29].

This also corresponds to historical accounts of the conquistador Francisco de Orellana (1511–1546), whose chronicler Gaspar de Carvajal reported sighting "numerous huge settlements," in the first trip along the Amazon in 1542, especially above the confluence of the Rio Negro. Retrospectively Carvajal specifically praised the people of the Amazon for their extraordinary intelligence and inventiveness, demonstrated in their "wonderful works" [47].

## **5. The black earth as climate savior: Wim Sombroek's vision**

In 1992 the Dutch soil scientist Wim Sombroek, who had previously devoted his doctoral thesis to the soils of the Amazon [48], outlined what would prove to be a watershed conceptual breakthrough in the on-going "*Terra Preta"* story.

In contrast to previous researchers who had enjoined *Terra Preta* research to ethnological, historical and archeological data, Sombroek infused climatic sciences and concerns into the *Terra Preta* dialog [49]. Sombroek sought to manufacture *Terra Preta Nova* or "new" black soil through the introduction of plant charcoal to nutrient-poor soils.

The addition of "Biochar" (plant charcoal) into the soil, sequesters carbon, diminishes the release of carbon dioxide and methane and provides for the soils' extended usefulness. The enhanced soils' new fertility, it was hoped, would provide a nutritional benefit to Amazonian farmers and could also be replicated elsewhere in the tropics.

Sombroek hoped this strategy could act as a counterweight to some of the pressures created by man-made global warming on extant agricultural practices. This combination of *Terra Preta* research with "climate change" concerns proved to be very ripe recipe indeed for both academic and public consumption and interest. It brought an otherwise obscure issue, a specific soil type, into the international spotlight.

Sombroek's new approach seemed to coincide with a new, global reckoning and awareness of the general climate change issue. In 1990 the United Nation's first IPCC (Intergovernmental Panel on Climate Change) report was issued, followed 2 years later by the U.N.'s Rio de Janeiro Earth Summit in June of 1992.

Existing elegantly at the intersection of environmental concern and hard science *Terra Preta* research took on a new life, birthing a robust research network and garnering unsuspected mainstream media attention. At the helm of this wave of interest was always the charismatic Wim Sombroek, who was duly recognized for bringing attention and funding to the fledgling world of *Terra Preta* research, he was even honored with a poem at his posthumous memorial service. He died in December 2003 [50].

**135**

**6. Terra Preta Nova**

*(Photo: J. Soentgen, 2015).*

**Figure 2.**

*From the "*Terra Preta de Indio*" to the "Terra Preta do Gringo": A History of Knowledge…*

At the core of Sombroek's research initiative was the goal of providing the inhabitants of Amazonia with a means to bring greater, more reliable harvests by

Wim Sombroek would probably be a great deal befuddled, if not downright dismayed, by the surprising direction his groundbreaking research has since taken. The *Terra Preta Nova*, as both a concept and a physical substance, has now been seized up by commercial interests and its being offered on the home improvement/horticultural market right alongside the more widely known "enhanced" home gardening soils. The rapid and profound proliferation of the *Terra Preta* model to large-scale commercial and agricultural uses has been supported by organizations like the International Biochar Initiative (BCI). Founded in July 2006 this body aims to support research on and commercialization of biochar suitable for the manufacture of

reinstating native soil improvement techniques (**Figure 2**) [51].

*A* Terra Preta *site used as papaya-plantation by the local population at the Rio Negro* 

black earth (www.biochar-international.com).

*DOI: http://dx.doi.org/10.5772/intechopen.93354*

*From the "*Terra Preta de Indio*" to the "Terra Preta do Gringo": A History of Knowledge… DOI: http://dx.doi.org/10.5772/intechopen.93354*

#### **Figure 2.**

*Ecosystem and Biodiversity of Amazonia*

Amazonia *Terra Preta* [29].

nutrient-poor soils.

in the tropics.

spotlight.

where hearth ashes are strewn on house gardens.

demonstrated in their "wonderful works" [47].

no longer seriously tenable [44, 45]. On the contrary, it is almost certain that at least some central components of the *Terra Preta* required deliberate actions with the purpose of soil enhancement at play. The introduction of charcoal on fields and plantings could be one such element which is current in Amazonia even today,

The discovery of the black earths has far-reaching significance for the history of the American continent, as it forces a total revision in estimating number of inhabitants in Amazonia prior to 1492. Because of the high and enduring fertility of *Terra Preta*, it now seems plausible that the area, before European invasion, would have had a population of several times the currently accepted approximate figure of one million people [46]. Currently a pre-colonial population of 8–10 million is considered quite plausible, based on estimates of the currently known acreage of

This also corresponds to historical accounts of the conquistador Francisco de Orellana (1511–1546), whose chronicler Gaspar de Carvajal reported sighting "numerous huge settlements," in the first trip along the Amazon in 1542, especially above the confluence of the Rio Negro. Retrospectively Carvajal specifically praised the people of the Amazon for their extraordinary intelligence and inventiveness,

In 1992 the Dutch soil scientist Wim Sombroek, who had previously devoted his doctoral thesis to the soils of the Amazon [48], outlined what would prove to be a

In contrast to previous researchers who had enjoined *Terra Preta* research to ethnological, historical and archeological data, Sombroek infused climatic sciences and concerns into the *Terra Preta* dialog [49]. Sombroek sought to manufacture *Terra Preta Nova* or "new" black soil through the introduction of plant charcoal to

The addition of "Biochar" (plant charcoal) into the soil, sequesters carbon, diminishes the release of carbon dioxide and methane and provides for the soils' extended usefulness. The enhanced soils' new fertility, it was hoped, would provide a nutritional benefit to Amazonian farmers and could also be replicated elsewhere

Sombroek hoped this strategy could act as a counterweight to some of the pressures created by man-made global warming on extant agricultural practices. This combination of *Terra Preta* research with "climate change" concerns proved to be very ripe recipe indeed for both academic and public consumption and interest. It brought an otherwise obscure issue, a specific soil type, into the international

Sombroek's new approach seemed to coincide with a new, global reckoning and awareness of the general climate change issue. In 1990 the United Nation's first IPCC (Intergovernmental Panel on Climate Change) report was issued, followed 2

Existing elegantly at the intersection of environmental concern and hard science

*Terra Preta* research took on a new life, birthing a robust research network and garnering unsuspected mainstream media attention. At the helm of this wave of interest was always the charismatic Wim Sombroek, who was duly recognized for bringing attention and funding to the fledgling world of *Terra Preta* research, he was even honored with a poem at his posthumous memorial service. He died in

years later by the U.N.'s Rio de Janeiro Earth Summit in June of 1992.

**5. The black earth as climate savior: Wim Sombroek's vision**

watershed conceptual breakthrough in the on-going "*Terra Preta"* story.

**134**

December 2003 [50].

*A* Terra Preta *site used as papaya-plantation by the local population at the Rio Negro (Photo: J. Soentgen, 2015).*

At the core of Sombroek's research initiative was the goal of providing the inhabitants of Amazonia with a means to bring greater, more reliable harvests by reinstating native soil improvement techniques (**Figure 2**) [51].
