Forest islands in the Llanos de Mojos, Bolivia, have distinctive soils that fit published definitions of terra mulata, a kind of Amazonian Dark Earth (ADE). The same soils also contain ceramics and burned clay. ADE is widely distributed in Amazonia, and Mojos is an important comparative case because ADE is found far from the floodplains of the major Amazonian tributaries, alongside and within agricultural earthworks. Although Mojos soils differ from Brazilian examples, they are relevant to larger discussions of ADE. In this particular case, ADE seems to be the product of dense settlement associated with ring ditches, which may have included intensively managed kitchen gardens. Pre-Columbian Mojeños used other strategies (such as raised fields) to improve soils for cultivation. Modern Bolivian farmers cultivate those improved soils intensively. Creation, maintenance, and use of ADE were part of a wide range of agricultural ways of life in pre-Columbian Mojos. Relationships between modern farmers and Amazonian soils are framed by these agricultural systems.