Some of the most impressive technological achievements of ancient Mesoamerican societies involved increases in the scale, efficiency, and overall productivity of agricultural land use systems. In late pre-Hispanic times, Mesoamerican farmers devised creative ways to meet the subsistence demands of burgeoning populations. Their solutions, which included terracing, irrigation, and raised fields, produced more food per unit of land than traditional farming methods. Anthropologists describe this process as “agricultural intensification,” which appears in many cases to coevolve alongside population growth and political centralization in the development of complex societies.
Agricultural intensification was a key economic process in the growth and development of the Aztec empire, which occupied highland central Mexico from the early 14th through the early 16th centuries AD. How the Aztec empire fed the large population of its capital, Tenochtitlan, has long intrigued researchers, since most of the city’s estimated 250,000 inhabitants at the time of Spanish contact in 1519 were not food producers. Feeding the residents of Tenochtitlan and other urban places in the region was primarily the job of rural farmers. Agricultural intensification and exploitation of locally available resources provided these farmers with a mixed economy that ensured local prosperity, while supplying urban areas with critically important staple goods and raw materials.
Capitalizing on the mosaic of microenvironments afforded by the Basin of Mexico, Aztec farmers combined three distinct farming techniques: terraced hillslopes irrigated by spring water that was carried long distances through complex networks of aqueducts, dry-farming fields watered by rain or alluvial flooding, and raised fields constructed as long rectangular plots in swamps and shallow lakebeds. These techniques were sometimes combined and supplemented with other methods, such as intercropping and fertilizing. This work, which took place year-round, produced very high yields of corn, beans, squash, fruits, chilies, chia, amaranth, and some species of cactus, all of which circulated widely in periodic community markets and in the Great Marketplace at Tlatelolco near the capital. In addition to providing daily sustenance, these staples were used in other ways in Aztec society, such as to mark social identity and hierarchy during political feasts, to pay tribute in support of the Aztec political economy, and to conduct religious rituals.
One of the greatest challenges for Aztec farmers was the poor condition of highland soils and the lack of arable land. Multiple agrotechnologies were brought together to address these problems. To improve soil quality, Aztec farmers left certain fields fallow for a period of time, and then used slash-and-burn techniques, in which trees were cut down, left to dry, and then set on fire; the resulting ash added nutrients to the soil. To increase the amount of cultivatable terrain, Aztec farmers built terraces along piedmont hillslopes. These terraces, made out of walls of stones, allowed farmers to use more land on the slopes and to move farther up the hillsides than otherwise possible. However, only a limited range of crops could be cultivated on these terraces due to the thin and rocky nature of upland soils. Plus, crops were usually dependent upon available rainwater, which made them susceptible to destruction by drought or heavy runoff from summer rainstorms. To buffer the risk of low productivity from terraced fields, Aztec farmers also created plots of land called chinampas (from the Aztec term, chinamitl, meaning “square made of cane”), artificial raised fields constructed in swamps and shallow lakebeds from layers of mud and vegetation.
Chinampas, which covered some 9,500 hectares (about 23,500 acres) in the basin’s two southern lakes, Xochimilco and Chalco, represented a highly productive form of intensive agriculture that provided up to one half or more of the food consumed in Tenochtitlan. In its most intensive form, cultivation was continuous throughout the year, producing two to four crops that yielded an annual surplus of 16,500 metric tons of corn. Fields were never left fallow; as soon as one crop was harvested, another set of seedlings was put in place. Scarce land was thus not tied up by long-cycle crops growing from seed. Whenever corn was cultivated, ground-hugging cultivars, such as beans and squash, were planted between the rows. Intercropping of this sort helped to keep soil nutrients in balance, since root action and silage of the bushier plants returned to the earth the minerals consumed by corn.
Modern aerial surveys show an overall uniformity in chinampa size and orientation, indicating a planned program of construction. Plots were rectangular fields 2 to 4 m wide (roughly 7 to 12 feet) and 20 to 40 m long (roughly 65 to 130 feet), surrounded on three or four sides by canals. Each plot was bordered by reeds, forming a fence around the plot, which was filled in with mud and decaying vegetation to raise the field surface just above the water level. The proximity of the field surface to the water table provided adequate soil moisture for crops and improved nighttime temperatures, reducing the chance of frosts. Soil fertility was maintained by periodically adding vegetation, household refuse, organic rich silt dredged up from the canal bottoms, and sometimes human excrement. The long and narrow layout between parallel canals, low profile above water, and layering of specific soil types obviated the constant need for irrigation.
The 16th-century Franciscan missionary, Bernardino de Sahagun, compiled an account of Aztec daily life from native informants, entitled “Historia general de las cosas de Nueva Espana,” which included an extraordinarily detailed narrative of cultivated plants and how they were used. These plants included corn, chia, and amaranth, as well as abundant varieties of beans, squashes, fruits, and chilies, all of which were farmed with a single kind of multipurpose digging stick known as the uictli.
The principal crop of Aztec farming was corn or “maize” (centli), which played an intimate part of the everyday lives of the Aztec. Maize was a central element to many stories, poems, and songs, as well as creation myths (the gods were said to have fashioned cornmeal into human flesh). Maize was prepared in numerous ways. The ear was consumed, the fiber was used for tea, maize honey was made from the tender canes, the fungus (cuitlacoche) was cooked and eaten, and the dry grains were used as the base for making tortillas, tamales, and a variety of gruel drinks. Atoles (atolli) were drinks made with maize dough mixed with water and sweetened with some kind of syrup or made spicy with the addition of chili. Pozol (pozolli) was a nutritious meal, taken as a drink prepared with nixtamal (boiled corn kernels in water with lime) and honey, chocolate, or dry chilies. A similar drink, yolatolli, was used as a curative for fever and some diseases.
Along with maize, beans were often served with meals and also included as ingredients in other dishes, such as tamales. Chia (chiematl) and amaranth (huauhtli) were used like maize in making pozol, and amaranth seeds were sometimes mixed with maize for making tamales. Cakes of amaranth seed dough were used in some religious ceremonies to adorn idols. There were more than one hundred varieties of chili peppers (chilli), which were mostly used to season foods, but some were eaten fresh, dehydrated, or smoked and pickled. The many varieties of squashes and fruits were eaten raw or cooked. Some species of flower—bishop’s weed, may flower, and zucchini flower—were cooked and used to prepare soups and teas.
Second only to maize, chocolate (chocolatl or xoxolatl) and cotton (ichcatl) were essential to both subsistence and political economies. Chocolate beans (cacao) sometimes served as a form of currency, especially for use in market exchange, where it was commonly accepted as payment for merchandise and labor. Writing in the mid-16th century, the Spanish priest and historian Bartolome de las Casas noted that one strip of pine bark for kindling was worth five cacao beans and one turkey egg cost three beans. Chocolate drink (ground, toasted cacao beans mixed with water and sometimes sweetened with honey or maguey syrup) was a prestigious beverage, reserved for people of high rank and consumed during special meals. Like chocolate, cotton was usually reserved for nobility; the woven fibers were often considered a prestige clothing of the elite. Cotton cloaks also appear to have had exchange value as currency. Depending on the quality, one cloak was said to be worth from 65 to 300 cacao beans. Unlike maize, however, cacao and cotton were grown outside the Basin of Mexico, including Morelos and the coastal regions of Veracruz and Oaxaca, and transported to the basin by means of trade and tribute.
Two types of cactus were cultivated, prickly pear (nopal) and agave or “maguey” (mexcalmetl). These succulents were important dietary supplements, especially in areas with low rainfall. Nopal and maguey were cultivated using dry-farming techniques, in which available rainfall was usually sufficient for watering crops. Nopal was roasted and eaten as a vegetable or served in tamales. The nopal plant also provided fruit (nochtli), which was consumed raw. Maguey provided medicine, fiber, building material, fuel, fertilizer, and intoxicating beverages. The most common fermented drinks were mezcal (metl) and pulque (poliuhqui). Pulque was usually reserved for consumption as a curative and on ceremonial occasions, including harvest festivals, rainmaking rituals, birth ceremonies, marriages, and funerals.
The Aztec considered the complementary themes of rain/moisture, maize and maguey, and agricultural fertility to be crucial to life-sustaining cosmological forces. As such, all agricultural practices were regulated by a calendrical system and a ritual almanac. The creator gods, Cipactonal and Oxomoco, created time in order to organize and plan earthly and divine phenomena and to give them sequence. Earthly time was organized according to the solar year (xiuitl), which was divided into 18 months of 20 days, plus 5 “unlucky” days (nemontemi). A great deal of the Aztec’s time and energy was devoted to ceremonies throughout the 18 months, most of which was aimed at placating deities of rain and agricultural fertility. These ceremonies coincided with the most critical periods in the agricultural cycle: the primary planting, growing, and harvesting seasons.
Divine time was structured by a ritual calendar (tonalpohualli), which consisted of 13 periods of 20 days each, creating a 260 count of days that were each associated with ceremonial observances. Each 13-day period was presided over by a patron deity or deities, including Tlaloc (god of rain) and other gods associated with fertility and agriculture, such as Xipe Totec (god of spring and new vegetation), Chicomecoatl (goddess of foodstuffs, especially maize and sustenance), Cinteotl (god of maize), and Xilonen (goddess of tender young maize). Each of the 20 days in the period also had a patron deity, who imparted special attributes to these days. For example, the patron of the rabbit (tochtli) days was Mayahuel, goddess of maguey, who presided over drinking and drunkenness.
The anthropological significance of Aztec agriculture is revealed in the Aztecs’ intensive and highly diversified agroeconomic system that stimulated specialization in areas of food production. Farmers in the drier reaches of the northern part of the basin specialized in nopal and maguey cultivation, while those in the south took advantage of a wetter climate for maize and bean agriculture; lowland farmers focused on cacao and cotton. Exchange between these regions sometimes enabled staple goods to be used to create and acquire durable valuables that could be amassed and redistributed as loans or gifts for building and enhancing social status and prestige. The Aztec agricultural system also yielded enormous surpluses of foods that enabled urban dwellers to focus their time and energy on non-food-producing enterprises, such as religious observances, governmental services, craft manufacture, and military duty. In this way, intensive agriculture and surplus production were extremely important factors in the development of Aztec society.
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