Circumstances Under Which the Garden was Investigated In the 1960s and 1970s, vast landscapes of abandoned pre-Columbian raised fields were documented in Peru, Bolivia, Ecuador, Colombia, Suriname, and Guyana. This form of intensive agriculture is associated with large and dense sedentary populations and in some cases sustained complex sociopolitical organizations. Raised fields are large elevated planting platforms designed to provide drainage and improve soil conditions and fertility. Deep water-filled canals alongside the platforms provide moisture during dry periods, protect crops against frost, and produce organic matter for sustained harvests.