Inca Civilization
Article

Waru Waru Raised-Field Agriculture on the Altiplano

The waru waru (also camellón in Spanish, or raised field in English) was a distinctive agricultural technology of the Inca state and of the pre-Inca polities of the Lake Titicaca basin. The waru waru consisted of an elevated planting platform, typically 10 to 20 meters wide and 50 to 100 meters long, surrounded by canals of water that absorbed solar heat by day and released it by night, raising the night temperature of the platform by several degrees Celsius and protecting the crops from frost. The system, which had been used in the Lake Titicaca basin since at least the Formative period (c. 1000 BCE), was greatly expanded by the Inca state in the fifteenth century, and the raised fields around the lake were estimated by the Proyecto Especial del Lago Titicaca in the 1990s to cover an area of perhaps 80,000 hectares. The ethnographer Clark Erickson has argued that the waru waru yielded as much as 10 metric tons of potatoes per hectare per year, making it among the most productive agricultural technologies in the pre-industrial world. The waru waru is one of the most striking examples of the technical sophistication of Inca food and agriculture, and the Inca hydraulic engineering of the state was closely integrated with the system.

Origins and pre-Inca antecedents

The raised-field technology of the Lake Titicaca basin has deep pre-Inca roots. Archaeological evidence from the site of Chiripa, on the southern shore of Lake Titicaca, shows that raised fields were already in use by approximately 1500 BCE, and the technology was further developed by the subsequent Wari and Tiahuanaco polities between 600 and 1100 CE. The Tiahuanaco state, in particular, expanded the waru waru system to a substantial portion of the altiplano surrounding the lake, and the raised fields of the Tiahuanaco period have been identified by archaeological survey in the districts of Puno, Huancané, and Tiahuanaco. The collapse of the Tiahuanaco state around 1100 CE, attributed by some scholars to a prolonged drought, led to the abandonment of many of the raised fields, but the technology was preserved in the local ayllus and was subsequently expanded by the Inca state.

The Inca expansion of the waru waru system was part of a broader program of agricultural intensification undertaken by the state in the fifteenth century. The chronicler Pedro Cieza de León recorded that the Inca emperor Pachacuti (r. c. 1438–1471) ordered the construction of new raised fields in the altiplano as part of his program of imperial consolidation, and that the labor of thousands of mit’a workers was mobilized for the work. The Spanish chronicler Pedro Sarmiento de Gamboa, writing in 1572, recorded that the waru waru of the altiplano were among the most productive agricultural lands of the empire, and that the produce of the fields was sent to the state qollqas at the provincial capital of Puno. The detailed treatment of Inca food and agriculture is given in the related article.

The technology of the waru waru

The waru waru consisted of an elevated planting platform, surrounded by canals of water. The platform was constructed by digging a series of parallel trenches in the surface of the altiplano, piling the excavated material into ridges between the trenches, and shaping the ridges into planting platforms. The trenches, which were typically 1 to 2 meters deep and 2 to 5 meters wide, were filled with water from a nearby stream or from the lake itself. The platforms, which were typically 10 to 20 meters wide and 50 to 100 meters long, were planted with the principal crops of the altiplano — potatoes, quinoa, and kañiwa — at the appropriate season.

The thermal regulation of the waru waru was the principal technical achievement of the system. The water in the surrounding trenches absorbed solar heat during the day, raising its temperature by several degrees Celsius above the ambient air temperature, and released the stored heat at night, raising the temperature of the planting platform by 2 to 5 °C. The effect was to protect the crops from frost during the cold nights of the altiplano growing season (typically August to May), when air temperatures can fall below -5 °C. The water in the trenches also served to irrigate the platforms, and the sediments deposited by the water served to fertilize the soil. The combined effect of the thermal regulation, irrigation, and fertilization was to make the waru waru substantially more productive than the surrounding puruma (open fields above the zone of permanent settlement).

The construction of the waru waru required a substantial labor investment. The chronicler Murúa recorded that a single waru waru of 1 hectare required approximately 200 to 300 worker-days to construct, and that the typical Inca waru waru of 5 to 10 hectares required the labor of perhaps 1,000 to 3,000 workers over a period of several months. The mit’a labor obligation was the principal mechanism by which the state extracted the necessary work, and the state used the labor of mitma colonists — settled in the altiplano from the central highlands — to construct and maintain the waru waru of the most important producing regions. The detailed treatment of the mit’a labor system and of the Inca hydraulic engineering is given in the related articles.

Productivity and the agricultural yield of the waru waru

The waru waru was among the most productive agricultural technologies of the pre-industrial world. The ethnographer Clark Erickson, who has studied the waru waru of the Lake Titicaca basin since the 1980s, has argued that the system yielded as much as 10 metric tons of potatoes per hectare per year, and that the yield of quinoa on the waru waru was approximately twice the yield on the surrounding puruma. The colonial Relaciones geográficas of 1570–1585 record that the typical waru waru in the altiplano of Puno produced approximately 7 to 10 metric tons of potatoes per hectare per year, and that the produce of the waru waru was the principal source of food for the population of the altiplano and the surrounding regions.

The productivity of the waru waru was a function of several factors. First, the thermal regulation of the system extended the growing season by several weeks, allowing the planting of longer-maturing varieties of potatoes. Second, the irrigation provided by the surrounding canals made possible the cultivation of the altiplano during the dry season, when the surrounding puruma were fallow. Third, the sediments deposited by the water in the trenches provided a continuous supply of nutrients, maintaining soil fertility over centuries of cultivation. Fourth, the waru waru was well suited to the rotation of potatoes, quinoa, and kañiwa that was the principal agricultural cycle of the altiplano, and the rotation maintained soil fertility without the use of fallow.

The high productivity of the waru waru was a substantial advantage to the Inca state. The state used the produce of the waru waru to support the army, the priests, and the population of the urban centers, and the waru waru were the principal source of the chuño that was stored in the state qollqas and distributed as famine relief. The chronicler Cieza de León recorded that the state qollqas of the altiplano held an estimated 20,000 to 30,000 tons of chuño and quinoa at any one time, and that the principal chuño fields of the empire were located near the waru waru of the Lake Titicaca basin. The detailed treatment of the Inca storage and qollqa system is given in the related article.

The social organization of the waru waru

The construction and maintenance of the waru waru required a substantial collective labor, and the system was closely integrated with the social organization of the local ayllu. The colonial visitas record that the typical ayllu of the Lake Titicaca basin maintained a series of waru waru of varying size, and that the labor of the ayllu’s households was mobilized for the construction of new waru waru and for the annual maintenance of the existing fields. The curaca of the ayllu was responsible for the assignment of the waru waru plots to the constituent households, and the camayoc (ritual specialist) of the ayllu was responsible for the calendar of sowing and harvest.

The state used the waru waru of the altiplano as a basis for the collection of tribute and the recruitment of labor. The quipucamayoc of the provincial administration recorded the yield of each waru waru in the quipu and computed the household’s tribute obligation; the tucuy ricuy (the inspector who toured the empire) verified the records and the productivity of the fields. The colonial visitas record that the state collected approximately 30 to 40 percent of the produce of the waru waru in tribute, and that the remainder was retained by the ayllu for the support of the households. The detailed treatment of the mit’a labor system and of the Inca provincial administration is given in the related articles.

The decline and the modern revival of the waru waru

The Spanish conquest of 1532 and the subsequent colonial administration led to a substantial decline in the waru waru system. The Spanish imposed the encomienda and later the repartimiento and the haciendas, which gradually concentrated land in the hands of a small Spanish and mestizo elite. The colonial administration encouraged the cultivation of European crops such as wheat and barley, and the waru waru were progressively abandoned. By the late colonial period, only a small fraction of the Inca-era waru waru remained in active use, and the technology was preserved principally in the memory of the local ayllus.

The waru waru was the subject of a substantial revival effort in the 1980s and 1990s, led by the Proyecto Especial del Lago Titicaca and by the ethnographer Clark Erickson of the University of Pennsylvania. The project, which was supported by the United Nations Development Programme and by the Inter-American Development Bank, reconstructed a substantial number of waru waru in the districts of Puno and Huancané and demonstrated that the system was capable of yields substantially higher than the surrounding puruma. The project also documented the persistence of the waru waru technology in the local ayllus and the importance of the system for the food security of the altiplano population. The detailed treatment of the Inca food and agriculture and of the Inca hydraulic engineering is given in the related articles; the potato and quinoa agriculture of the altiplano is treated in the related articles.