Wolfgang Zech, & Bruno Glaser

Abstract The first description of Terra Preta soils goes back to Hartt (1871) known at this time as "terra cotta". This term is based on a sequence of archaeological publications indicating that to that date ceramics were probably the only relics of ancient cultures. As old as the Terra Preta investigation is the question of its origin. Barbosa de Farias (1928) proposed that Terra Preta sites were already fertile before they were settled by the native population. Thereafter, a sequence of geogenic origins was proposed. For instance, volcanic (Hilbert, 1955) and fluvial (Zimmermann, 1958; Franco, 1962) sedimentation (Hilbert, 1955) were suggested. The first suggestion of an anthropogenic origin of Terra Preta soils was proposed by Gourou (1949). Since then this theory was favored by Ranzani (1962), Sombroek (1966), Hilbert (1968), Falesi (1972), Zech et al. (1979, 1990), Smith (1980, 1999),Glaser (1999), and Woods (1999, 2000). During the 60s and 70s, Terra Preta sites all over the Amazon basin were mapped and investigated with respect to soil physical and chemical parameters supporting the anthropogenic origin of Terra Preta soils. In the 80s it was thought that Terra Preta is a kind of kitchen-midden, which has acquired its specific fertility, from dung, household garbage, and the refuse of hunting and fishing (Zech et al., 1990). However, the detailed mechanisms by which Terra Preta humus gained its stability and special properties were still subject to speculation. At the end of the 90s, investigations on molecular level showed that Terra Preta contained tremendous amounts of charring residues which are known to contain high amounts of nutrients and to persist in the environment over centuries. Future investigations should focus on the identification of land-use practices of the pre-Columbian population and on the implementation of this knowledge in order to produce new Terra Preta sites.