Some quotes speaking about the Amazonian forest and soil:
[...]"what the eco-imagery would like to picture as a pristine, untouched Urwelt [primeval world] in fact has been managed by people for millennia."
[...]
According to Susanna Hecht, a geographer at the University of California at Lost Angeles, researchers into upland Amazonia took most of their soil samples along the region's highways, which indeed passed through areas with awful soil [...] A few scientists, though, found patches of something better [...] in the 1990s researchers began studying these unusual regions of terra preta do Índio--rich, fertile "Indian dark earth" that anthropologists believe was made by human beings.
[...]
Because terra preta is subject to the same punishing conditions as the surrounding bad soils, "its existence is very surprising," according to Bruno Glaser, a chemist at the Institute of Soil Science and Soil Geography at the University of Bayreuth, Germany. "If you read the textbooks, it shouldn't be there."*
[...]
According to a recent study led by Dirse Kern, of the Museu Goeldi in Belém, terra preta is "not associated with a particular parent soil type or environmental condition," suggesting that it was not produced by natural processes. Another clue to its human origin in the broken ceramics with which it is usually mixed. "They practiced agriculture here for centuries," Glaser told me. "but instead of destroying the soil, they improved it, and that is something we don't know how to do today" in tropical soils.
~1491: New Revelations of the Americas before Columbus by Charles C. Mann, p344-5.
ISBN 978-4000-3205-1
[...]
According to Susanna Hecht, a geographer at the University of California at Lost Angeles, researchers into upland Amazonia took most of their soil samples along the region's highways, which indeed passed through areas with awful soil [...] A few scientists, though, found patches of something better [...] in the 1990s researchers began studying these unusual regions of terra preta do Índio--rich, fertile "Indian dark earth" that anthropologists believe was made by human beings.
[...]
Because terra preta is subject to the same punishing conditions as the surrounding bad soils, "its existence is very surprising," according to Bruno Glaser, a chemist at the Institute of Soil Science and Soil Geography at the University of Bayreuth, Germany. "If you read the textbooks, it shouldn't be there."*
[...]
According to a recent study led by Dirse Kern, of the Museu Goeldi in Belém, terra preta is "not associated with a particular parent soil type or environmental condition," suggesting that it was not produced by natural processes. Another clue to its human origin in the broken ceramics with which it is usually mixed. "They practiced agriculture here for centuries," Glaser told me. "but instead of destroying the soil, they improved it, and that is something we don't know how to do today" in tropical soils.
~1491: New Revelations of the Americas before Columbus by Charles C. Mann, p344-5.
ISBN 978-4000-3205-1