This paper discusses the agricultural system in the Charazani region in the Bolivian Eastern Cordillera. The zone from 2800 m to 4300 m asl is intensively used by Indian people and a small Mestizo group. Their traditional agriculture reflects both Indian and Spanish (16th century) traditions. Such traditional systems have been subject to rather contrary myths: some call them primitive, others ecologically adapted. Studying key variables of soil fertility (concentrations and contents (pools) of organic carbon and utilizable water storage capacities) we will investigate the degree of ecological adaptation of the soil-use system in the Charazani region. These parameters, studied in 110 field sequences covering 0-30 cm soil depth, are discussed according to their absolute levels, differences between semi-natural and agriculturally used areas, and (only for organic carbon contents) actual changes during continuous management. The results show that land-use on the dry, wind-exposed and nor irrigated sites is often insufficiently ecologically adapted. Here, intensive crop farming and sheep pasture without protection against wind erosion result in low and even decreasing soil fertility. Good ecological adaptation according to the investigated parameters is to be found, by contrast, on the more humid and better wind-protected sites as well as on the irrigated areas.