An indigenous Incan system of raised fields evolved in the high plains of the Peruvian Andes about 3000 years ago,. The platforms of soil were surrounded by ditches filled with water, which were able to produce bumper crops even despite the exposure to floods, droughts and frosts at high alititudes. Terraces minimize risk to drought and frost, reduce soil loss and broaden cropping options because of the improvements afforded by microclimatic and hydraulic advantages. These techniques have been revived through the efforts of Proyecto Interinstituticional de Rehabilitacion de Waru-Warus (PIWA) to moderate temperatures, extend the growing season, and lead to higher productivity compared with chemically fertilized production in the same area.
In Huatta district, reconstructed waru-warus led to a yield of 8-14 t/ha/year of Puno potatoes, compared with the average yields of 1-4 t/ha/year. Quinoa yields were also improved, producing 2 t/ha/year.
Waru-waru reconstruction is labor intensive, requiring an estimated 270 person-days/ha/year. In southern Peru, PRAVTIR offers low-interest loans and seeds or other inputs for the resoration of large areas of abondoned terraces.