Ancient Ridged Fields in the Region of Lake Titicaca

Abstract

Minor landscape features which are apparently the result of pre-Columbian cultivation on poorly drained ter ain h v recently b en describ d in various parts of lowland South America. The most spectacular vestiges of these ancient ridged fields are in the seasonally inundated tropical savannas of the San Jorge floodplain of northern Colombia (Parsons and Bowen, 1966) and the Llanos de Mojos of northeastern Bolivia (Denevan, 1963; Denevan, 1967; Plafker, 1963). Similar fields have been traced in the Orinoco Llanos, in Surinam and near Guayaquil in Ecuador (Parsons and Denevan, 1967). They consist of parallel or irregular groupings of raised ridges of variable height, width and length: from a few inches to several feet in height, from about 10 to 70 feet in width, and up to several thousand feet in length. They are indicative of a careful and laborious reclamation of marshland for intensive tropical agriculture in areas which are considered marginal for agriculture today, or in which crop cultivation has been entirely abandoned. The reclamation of marshland for agriculture was also practised in the higher cultures of the New World in the highlands of Mexico and the Andes. The chinampa or 'floating garden' agriculture of the Valley of Mexico is well known, and the form and patterns of dry, abandoned chinampas are remarkably similar in appearance to some of the ridged fields of South America (Coe, 1964). A few elevated crop platforms have also been observed in poorly drained parts of the Sabana de Bogota in Colombia (Eidt, 1959). But the largest area of ancient ridged fields so far discovered in the Americas is in the region of Lake Titicaca in Peru and Bolivia on level ground at 3800 and 3890 m (12,500 to 12,800 ft) above sea level. These previously undescribed features, now used mainly for pasture, are almost certainly of pre-Inca origin, and their existence helps to confirm other indications of a dense pre-Columbian Indian population in the area.