1491_ New Revelations of the Americas Before Columbus - Charles C. Mann [177]
Indians are still making terra preta in this way, according to Hecht, the UCLA geographer. Hecht spent years with the Kayapó, in central Amazonia, watching them create “low-biomass” fires “cool enough to walk through” of pulled-up weeds, cooking waste, crop debris, palm fronds, and termite mounds. Burning, she wrote, is constant: “To live among the Kayapó is to live in a place where parts of the landscape smolder.” Hecht regards Indian fire as an essential part of the Amazonian landscape, as it was in the forests of eastern North America. “We’ve got to get over this whole Bambi syndrome,” she told me, referring to the movie’s forest-fire scene, which has taught generations of children that burning wildlands is evil. “Let the Kayapó burn the rainforest—they know what they’re doing.”
In a preliminary test run at creating terra preta, Steiner, Wenceslau Teixeira of the Brazilian Agricultural Research Enterprise, and Wolfang Zech of the University of Bayreuth applied a variety of treatments involving charcoal and fertilizers for three years to rice and sorghum plots outside Manaus. In the first year, there was little difference among the treatments (except for the control plots, in which almost nothing grew). By the second year, Steiner said, “the charcoal was really making a difference.” Plots with charcoal alone grew little, but those treated with a combination of charcoal and fertilizer yielded as much as 880 percent more than plots with fertilizer alone. His “terra preta” was this productive, Steiner told me, despite making no attempt to re-create the ancient microbial balance.
Beginning a little more than two thousand years ago, the central and lower Amazon were rocked by extreme cultural change. Arawak-speaking groups migrated in from the south and west, sometimes apparently driving Tupí-speaking groups north and east. Sedentary villages appeared. And so did terra preta. No one yet knows if or how these events were related. By about the time of Christ the central Amazon had at least some large, settled villages—Neves, Petersen, and Bartone excavated one on a high bank about thirty miles up the Río Negro. Judging by carbon dating and the sequence of ceramics, they believe the site was inhabited in two waves, from about 360 B.C., when terra preta formation began, to as late as 1440 A.D. “We haven’t finished working, but there seems to be a central plaza and some defensive ditches there,” Petersen told me. The plaza was at least a quarter mile long; the ditch, more than three hundred feet long and up to eighteen feet wide and six feet deep: “a big, permanent settlement.”
Terra preta showed up at the papaya plantation between 620 and 720 A.D. By that time it seems to have been underneath villages throughout the central Amazon. Several hundred years later it reached the upper Xingú, a long Amazon tributary with its headwaters deep in southern Brazil. People had lived around the Xingú for a long time, but around 1100 or 1200 A.D., Arawak-speaking people appear to have moved in, jostling shoulders with people who spoke a Tupí-Guaraní language. In 2003 Heckenberger, who had worked with Petersen and Neves, announced in Science that in this area he and his colleagues had turned up remains of nineteen large villages linked by a network of wide roads “in a remarkably elaborate regional plan.” Around these settlements, which were in place between approximately 1250 and 1400 A.D., the Xinguanos built “bridges, artificial river obstructions and ponds, raised causeways, canals, and other structures…a highly elaborate built environment, rivaling that of many contemporary complex societies of the Americas and elsewhere.” The earlier inhabitants left no trace of terra preta; the new villages quickly set down thick deposits of black earth. “To me,” Woods said, “it looks as if someone invented it, and the technique spread to the neighbors.”
Because Amazonia lacks stone