Maize in Inca Agriculture: Terraces, Ritual, and Storage

Maize (Zea mays) was the prestige crop of the Inca state and the central element of its public cult. Although it was less productive per unit of land than the potato, it was central to religious ritual: a jar of maize beer (chicha) was poured at every shrine, at every sacrifice, and at every important social interaction. The chronicler Garcilaso de la Vega, who grew up in Cusco in the mid-sixteenth century, recorded that maize was offered to Inti, the sun god, at the Coricancha every morning before sunrise. Maize was also the staple of feasting at Inti Raymi and other major festivals, and the distribution of maize from the state qollqas to the population of Cusco was one of the principal functions of the imperial economy. The cultivation of maize in the Inca state required a substantial investment of labor in terracing, irrigation, and storage, and the agricultural landscape of the Sacred Valley is, in many respects, the landscape of Inca maize.

Origins and the diversity of Andean maize

The cultivated maize was domesticated in the Balsas river valley of present-day Mexico at least by 6700 BCE, and possibly as early as 9,000 years ago, on the basis of phytolith evidence from the San Andrés site in the Gulf of Mexico reported by the archaeobotanist John Jones in 2009 — and it was brought to the central Andes by the long-distance exchange networks of the Chavín and Wari horizons. By the time of the Inca state, the crop had been adapted to the highland environment by thousands of years of selective breeding, and the Incas distinguished some fifty or more varieties of maize, classified by color, by the size of the cob, and by the altitude at which they would mature.

The most prestigious varieties were the q’ello sara (yellow maize), the yuraj sara (white maize), and the yana sara (black or dark purple maize); the last was reserved for the Sapa Inca and for the Temple of the Sun. The chronicler Murúa recorded that the imperial aclla wasi (house of the chosen women) maintained separate fields for each variety and that the harvest of the yana sara was performed by the acllas themselves, under the supervision of the high priest of the sun. Other important varieties included the puca sara (red maize), the q’osñi sara (purple maize), and the paraqay sara (a high-altitude variety cultivated in the Collasuyu). The diversity of Andean maize is documented in detail in the modern ethnobotanical literature — most notably in the work of the Peruvian agronomist and maize specialist Antonio Brack Egg — and the CIP in Lima maintains a gene bank of more than 6,000 accessions of Andean maize varieties.

The maize belt: altitude, climate, and the limits of cultivation

Maize was grown in the Inca state at altitudes from sea level to approximately 3,800 meters, with the principal producing regions concentrated in the maize belt of 2,500 to 3,500 meters. The maize belt of the central Andes was a narrow band of temperate valleys — the Sacred Valley of the Vilcanota, the Urubamba, the Colca, the Cotabamba, and the Cajamarca — where the climate was mild enough to support the long growing season of maize (typically 150 to 200 frost-free days) and the rainfall was sufficient for the crop. Above 3,500 meters, the growing season became too short and the night frosts too frequent, and maize was replaced by potatoes and quinoa as the staple crop.

The Incas extended the range of maize cultivation in the highlands by two principal techniques. First, the construction of andenes — terraced fields that retained heat, regulated moisture, and created microclimates in which maize could be grown at altitudes above 3,500 m. The terracing system of Pisac, with its twenty or more concentric levels cut into the hillside above the town, was one of the most elaborate of the Inca terracing complexes, and the system of terracing at Ollantaytambo was another. Second, the construction of irrigation canals that brought water from glacial sources to fields many kilometers away, and the development of frost-protection techniques based on the use of smoke and water. The chronicler Cieza de León recorded that the maize fields of the Chinchaysuyu yielded two harvests a year — a remarkable achievement that the chronicler attributed to the fertility of the soil and to the skill of the Andean farmers.

The construction of the terracing system required a substantial labor investment, and the mit’a labor obligation was the principal mechanism by which the state extracted the necessary work. The chronicler Betanzos recorded that the terraces of Pisac were constructed in the reign of Pachacuti, in the mid-fifteenth century, and that the labor of 4,000 workers was required for a single year. The terraces have been dated by archaeological excavation to the reign of Pachacuti, and they have been continuously maintained by the local ayllu in the centuries since the conquest. The detailed treatment of the Inca terracing system and of Inca hydraulic engineering is given in the related articles.

The ritual use of maize and the brewing of chicha

Maize was central to Inca religious ritual. The chronicler Cieza de León recorded that the imperial temple of the sun in Cusco maintained a continuous offering of maize — typically a basket of maize, a jar of chicha, and a llama — that was renewed every morning by the high priest of the sun. The offering was performed at the rising of the sun, and the public was admitted to witness the ceremony. Maize was also offered at the principal shrines of the empire — the Temple of the Sun, the Temple of Viracocha at Raqchi, the Temple of the Earth at Pachacamac — and the chronicler Cobo recorded that the state maintained a complex calendar of offerings in which maize was poured at particular shrines on particular days of the month.

The principal use of maize in ritual was the brewing of chicha — a fermented maize beer of moderate alcohol content (typically 1 to 3 percent) that was the staple drink of the Andean world. The brewing of chicha was a complex process, well documented in the colonial Relaciones geográficas de Indias of 1570–1585, in which the maize was first germinated (a process known as q’oni, which activated the enzymes that converted the starch to sugar), then ground, then boiled, then fermented for several days. The principal breweries of the empire were the aclla wasi — the houses of the chosen women — and the qollqa of the major provincial centers. The acllas of the imperial aclla wasi in Cusco were responsible for the production of the highest-quality chicha, which was consumed at the principal state feasts and was given as a gift to the senior officials of the empire.

The consumption of chicha was central to the social and ritual life of the Andean world. The chronicler Garcilaso de la Vega recorded that chicha was consumed at every significant social interaction — at marriages, at births, at deaths, at the principal festivals of the year — and that the act of sharing a jar of chicha was the principal mechanism by which social bonds were formed and reinforced. Chicha was also offered to the mallkis (mummified ancestors) of the ayllu, and the chronicler Cobo recorded that the household’s daily offering of chicha to the family’s mallki was one of the principal acts of household ritual. The detailed treatment of the brewing of chicha and of its role in the social life of the empire is given in the related article on maize agriculture and in the article on Inca religion and mythology.

The storage of maize in the qollqa system

Maize was stored in the state qollqa system and in household trojes. The state qollqas were stone structures, typically circular or rectangular, with walls of fitted stone and an internal diameter of 3 to 6 meters; they were designed to maintain a constant, low temperature and humidity, and the most elaborate examples — such as the 700-plus qollqas of Huánuco Pampa — were capable of holding several hundred tons of maize each. The maize was stored in the qollqas in large woven baskets (q’epi) and was regularly inspected and turned over to prevent spoilage.

The state qollqa system was the principal mechanism by which the imperial administration distributed maize to the army, to the priests, and to the population of Cusco. The chronicler Cieza de León recorded that the state distributed approximately 4,000 to 5,000 tons of maize per year to the population of Cusco, in rations calibrated to the household’s size and to the household’s mit’a labor obligation. The state also used the qollqa system to maintain a reserve of maize for famine relief, and the chronicler Pedro Pizarro recorded that the state sent food caravans of up to 4,000 llamas to communities hit by drought or frost. The detailed treatment of the Inca storage and qollqa system is given in the related article.

Maize and the imperial diet

Maize was the prestige food of the imperial diet. The chronicler Murúa recorded that the Sapa Inca consumed maize at every meal, typically in the form of sara api (a thick porridge of maize flour), sara kanka (toasted maize), or chicha. The panaca nobles of Cusco consumed maize in similar forms, supplemented by the meat of llamas, alpacas, and cuy (guinea pig). The hatun runa of the central highlands consumed maize principally at festival time, and their daily diet was based on chuño and other tubers. The consumption of maize in the rural ayllus was substantially lower than in the urban centers, and the colonial visitas record that the typical highland household consumed perhaps 50 to 100 kilograms of maize per year, supplemented by several hundred kilograms of chuño and smaller quantities of quinoa.

The introduction of maize to the highland diet was a substantial improvement in the nutritional status of the Andean population. Maize is rich in carbohydrates and provides a substantial amount of protein (approximately 9 percent by weight of dry maize flour), and its consumption complemented the protein-rich quinoa and the calorie-dense chuño. The combined diet of maize, potatoes, and quinoa provided a balanced nutritional profile that supported a population of perhaps ten million people in the Tawantinsuyu at the time of the conquest. The detailed treatment of the Inca diet and of the role of maize in the imperial food economy is given in the related articles.