Rural Indians and Technological Innovation, From the Chinampas of Xochimilco and Beyond
Summary and Keywords
When the anthropologist Paul Kirchhoff proposed a new definition of Mesoamerica in a landmark study from 1943, the first common characteristics he identified were technological and agricultural: the use of the digging-stick (coa) and “the construction of gardens by reclaiming land from lakes (chinampas).” For thousands of years, Native peoples across Mesoamerica drew on their technological innovations to devise bountiful kinds of farming that have been as diverse as the environments in which they were created. All of their farming systems required some degree of intervention in nature, be it through domesticating plants, tilling the soil, or altering the physical environment by making terraces and harnessing water supplies. On an essential level, then, technology and agriculture went hand in hand. Of the many kinds of Mesoamerican farming, the one that arguably modified the environment the most was a distinctive kind of wetland agriculture in which Nahuas—or Aztecs, the speakers of the Nahuatl language—constructed raised garden beds, known as chinampas, in the shallow, freshwater lakes of the Basin of Mexico.
At the heart of this zone of wetland agriculture was the ancient city of Xochimilco. There the raised gardens filled the surrounding lake of the same name, and eventually came to cover a vast area of some 120 square kilometers. The construction and the intensive cultivation of the chinampas required a considerable investment of time and effort, a good deal of technical expertise, and the mastery of specialist skills and knowledge, including hydrology and engineering so as to manage water levels in the lakes through complex irrigation works. The intensive farming of the fertile, well-irrigated gardens, which could be cultivated year round, yielded sizable harvests of maize and other crops. So productive was chinampa agriculture that scholars have considered it one of the most abundant kinds of farming ever devised. As a technological innovation and environmental adaptation, the chinampas were crucial to changes in Mexican history: they generated surpluses sufficient for urbanization and the rise of Tenochtitlan, one of the early modern world’s great cities, as well as the expansion of the Aztec Empire. The chinampas remained important for the provisioning of the capital long after the Spanish conquest, and in spite of the desiccation of the Basin of Mexico, they are still cultivated in a few places today.
Ancient Agriculture and Technology
The first identifiable technologies of Mesoamerica’s Native peoples can be traced back to the distant, prehistoric past. Lithic technologies, including the fashioning of lethally sharp obsidian blades and the polishing of elegant jade masks, are early examples of these innovations. Other breakthroughs included the discovery and manipulation of rubber and the making of bark paper. Further advances can be seen in the production of ceramics, the weaving of textiles, the working of such metals as silver, gold, copper—and its alloys—as well as the making of paints and pigments from minerals, the transformation of limestone into stucco, and the construction of stepped pyramids. While all of these innovations contributed to further advances in architecture, writing, religion, and other spheres of human ingenuity, no single revolution was as radical in its implications for cultural change as the domestication and cultivation of plants. Mesoamerica was one of just seven places in the world where humans, without outside inspiration or influence, developed agriculture and, as a result, created complex urban societies.1
The earliest signs of the domestication of plants date as far back as 10,000 bp (years before the present) along the east coast of Mexico and in what are the present-day states of Puebla and Oaxaca. The first plants to be modified through human intervention belonged to the genus Cucurbita, which included the ancestors of squash and gourds. Early peoples of Puebla and Oaxaca were also the first to cultivate cereals. There is evidence that dozens of varieties of maize, all belonging to the species Zea Mays, were derived from a wild grass known as teosinte around 4000 bp. Other plants that Native Americans subsequently domesticated included amaranth, beans, and chilies. Their cultivation spread across Mesoamerica, giving rise to early agricultural communities in the period between 1500 and 1000 bce (before the Common Era). The shift to village life was accompanied by the rise of new technologies for the preparation of food. Some of these tools were fashioned from stone, as with metates (grinding stones, originally metatl), manos (rolling pins), and comales (griddles, from comalli in Nahuatl). Others followed from the invention of ceramics. Native peoples used earthenware pots to cook tamales, tortillas, and nixtamal, an alkaline solution in which lime is added to make up for the lack of niacin in maize.2
Beyond intervention in plant reproduction, the selection of seeds, and gradual genetic modifications of plants, Native Americans also made several further advances in agriculture. They made use of multiple cropping, in which maize, beans, and squash were raised at the same time to increase yields and to maintain nutrients in the soil, which would otherwise be depleted with harvests. Changes in farming also included the fashioning of agricultural implements, such as axes, which Native peoples used to fell trees and clear brush when preparing fields, as well as the huictli, a kind of spade, and the huitzoctli, a fire-hardened planting stick for making holes in the soil into which farmers deposited individual seeds. Indigenous peoples typically planted by hand kernels of maize and seeds for beans, squash, and tubers, among them jicama and sweet potatoes. Before planting, though, the soils would have been improved with the use of fertilizers made from vegetation, lime, or bat droppings.
Increasingly intensive agriculture, made possible by irrigation, led to more profound alterations of the environment. Irrigation and cultivation practices, in turn, varied according to the circumstances of local geography and ecology. The Maya, for instance, employed swidden (slash and burn) agriculture of long or short fallow periods, typically of two to twenty years. At the same time, the Maya also maintained orchards and made use of arboriculture, with groves of perennial plants, including cacao trees. And they pioneered intensive forms of permanent agriculture in which, at least initially, they irrigated fields by channeling water from rivers. Across Mesoamerica, irrigation typically led to the farming of three types of field: drained fields; raised horticultural beds with furrows, known as camellones in Spanish; and terraces, which enabled cultivation on what had previously been sloping land. One common type were metlapantles, hillside terraces whose borders were held in place by agave plants.3
The earliest networks of canals in central Mexico have been dated to 1000 bce. Their expansion allowed for greater areas of land to come under cultivation, which in turn made for greater yields, population growth, and urbanization. Nowhere in ancient times was the close correlation between irrigation and urbanization more apparent than at Teotihuacan. There archaeologists have charted the tandem rise of the canal network and the immense city that, at its height, may have had 100,000 inhabitants, if not more. The interconnected processes of technological, agricultural, and demographic change found their ultimate expression in the famous system of chinampa agriculture in the Basin of Mexico. These raised gardens came to support a great urban population during the Postclassic period (c. 900–1521 ce), numbering in the tens if not hundreds of thousands.4
The Origins of Chinampa Agriculture
While there is some controversy among archaeologists and geographers about the origins and antiquity of chinampas, they have clearly been cultivated for hundreds and perhaps thousands of years. Some scholars have argued that the earliest forebears of the chinampas can be traced to 1000 bce. Others are skeptical about such a date, cautioning against drawing firm conclusions on the basis of archaeological data that is far from unambiguous: ceramic artifacts found in the remnants of ancient plots, for instance, might not date to the time when the gardens were actually constructed; rather, they might have already been in soil that was imported for the express purpose of making the chinampas. Other scholars have suggested that the gardens’ earliest traces can be seen in the layered platforms of soil and vegetation, which were housed within enclosures at the site of El Terremote in Lake Xochimilco. (The term chinampa derives from the Nahuatl word chinamitl, meaning enclosure or fence.)5 These formations date to the Preclassic period, c. 1000 bce.6
Aquatic garden cultivation became increasingly common in Lakes Xochimilco and Chalco during the Classic era. As this kind of farming expanded, so too did the settlement of lakebed islands and city-states such as Xochimilco, Tlahuac, and Mixquic. At first, irrigated drained fields were established along the lakeshore, with indigenous residents digging trenches that were perpendicular to the shoreline and extended into the water. These irrigation ditches allowed for drainage into the lake; conversely, during dry months, water could be scooped from the trenches and sprinkled onto the fields. Residents also devised a second type of lakeshore field in which soil that had been excavated in the making of trenches was heaped onto the adjacent plots of land, enabling the gardens to rise above the water level. With both of these types of fields the lakes themselves remained essentially unmodified.7
Over time, indigenous people pushed ever farther into the lakes by creating artificial, raised gardens. These chinampas were entirely surrounded by water. Their construction required that two preconditions be met: first, that the lakes be shallow; and second, that the water levels of the lakes be regulated and kept constant—in other words, that the lake environment be altered through engineering works. At first, these water management programs consisted of canals, dikes, and sluicegates. The dikes encircled a small section of the lake, creating a pool, or lagunilla. These pools spread out from the lakeshore, particularly at bays and inlets, as well as along the edges of island towns such as Tlahuac and Xico. Gradually, indigenous people built successive rings of these lagoons farther out into the lakes. The dike at the end of one pool thus served as the first barrier for the next. The water levels in these hydraulic compartments were closely regulated and were typically kept slightly above the surrounding lake, so as to reduce the risk of damage from inundation during the rainy season. Conversely, in dry spells, water could be directed from springs and streams into the pools rather than being lost in the circumambient lake. (For maps and plans of chinampas and the hydraulic compartments, see the images of “The Mapas Project,” listed in the links to digital sources.)8
The maintenance of consistent, well-regulated water levels was essential to the success of chinampa cultivation, which was (and remains) a precise and technical art. The surface of the garden plots, for example, had to rise to the correct height above the water—at least 25 centimeters and more commonly 80 cm to 1.2 meters—so that the soil would not become too moist. If the roots of crops remained submerged they would perish. At the same time, the roots had to be close enough to moisture to allow for the upward capillary movement of water, but not at such a height that this would fail to happen. The determination of the correct height of the chinampa, and the maintenance of the appropriate water levels demanded a great deal of expertise, not least because of seasonal fluctuations in rainfall, variations in the water levels across adjacent hydraulic compartments, and changes across the entire lacustrine system, in which a rupture at one place might be lead to flooding far afield.9
The making of the chinampas was no less complex and intricate. Although stratigraphic surveys of archaeological sites have shown that there were different kinds of chinampa, according to the materials used in their composition, they were all made in more or less the same general way. First, water levels were lowered in the hydraulic compartment so that indigenous people could search for a suitably shallow site for their chinampas. They did so by using poles to take soundings. After a foundation, or cimiento, was identified, its dimensions would be determined and its perimeter staked out with reeds. The farmers would then dredge muck from the lakebed using shovel-like implements and a zoquimaitl, a pole with a bag attached to one end. The dredging would be done in such a way as to create ditches around the field’s edges, which separated the individual plots and provided irrigation. After the plot had been partially raised, farmers would then create a césped, a bed of vegetation made from the aquatic plants. The césped, which provided essential nutrients for the soil, would be placed on the field and then, on top of it, more mud would be deposited, with this process being repeated until the plot reached its correct height. To stabilize the edges of the plot farmers planted water willows (ahuejotes) or cypress trees (ahuehuetes). The roots of these trees reinforced the sides of the chinampa and prevented them from subsiding. Once the enclosures were secured and the entire structure had been built, fertilizers were applied. The fertilizers typically consisted of night soil and, if the farmer were growing chilies, bat guano. Once the fertilizer had been applied, the soil would be tilled and, finally, the chinampa would be ready for planting.10
The making and preparation of the chinampas thus involved a considerable investment of labor. Typically, a group of four to six people would work for eight days to make a single chinampa. Yet more workers, of course, would be needed to build and maintain the embankments for the surrounding hydraulic compartment. Such labor would have been recruited locally, as part of customary rotational drafts. Experience had taught Nahuas that while the length of the chinampas could vary according to the local geographical situation—from ten to hundreds of meters—the width of the plots had to be consistently narrow. Usually, they were two to four meters wide, with the average being 3.75 meters. The slender dimensions were essential because they allowed for the seepage of water into the soil while also ensuring that the chinampa retained the right amount of moisture. Typically, the chinampas were rectangular, although the relics of some ancient plots have been observed as taking on a variety of profiles, among them U-shaped, E-shaped, J-shaped, and comb-shaped beds. (These relic chinampas, or “ghosts,” as one scholar termed them, became visible from above when the lakes lost much of their water in the 20th century; aerial photos taken in the 1940s captured their outlines.) The variations in the shape of the chinampas likely reflected local geographical forms, and they were clustered together to maximize the space available in their hydraulic compartments. Regardless of their actual lengths and shapes, though, the ratio of land to water was 1:1 in the southern lakes of Xochimilco and Chalco. In other words, half of the lakes were land. Local residents essentially transformed the lake environment: the lakes became as much earth as they were water.11
The cultivation of chinampas was just as labor intensive as their making. Before planting, seeds were often grown on nurseries that floated next to the chinampas. These nurseries had the advantage of freeing up space on the chinampa, enabling the new crop to be prepared for planting while the previous one matured and became ready for harvesting. (The floating rafts are the source of the common confusion and misnomer of chinampas as “floating gardens,” which dates back to observations by Spaniards in the early colonial period.) Once the seeds had sprouted, the farmers would select the most robust ones and transplant them to the chinampa. The selection of the healthiest shoots enabled farmers to achieve higher crop yields. The use of seedbed nurseries also allowed for continuous cycles of cultivation throughout the year, so long as the farmers employed multiple cropping. A common cycle followed the successive planting of maize, chilies, and tomatoes. In any given year, a single chinampa could yield five to seven harvests, with two of them including maize. Other crops included amaranth, beans, squash, and other vegetables.12
Indigenous people went to such great lengths in constructing and cultivating the chinampas because of the many, great advantages they afforded farmers. The location of the gardens in the lakes, and their continual immersion in a regulated water supply, meant that they were ideally irrigated. In addition to the seepage of lake water into the porous soil (known as sub-irrigation), chinampa farmers could ensure that their crops remained properly hydrated with splash and scoop techniques. The regular, consistent watering of the plots was a tremendous boon given the variability in rainfall and the risk of drought. In an early-17th-century account given to the Spanish government in Mexico City, Nahuas from Xochimilco extolled the benefits of chinampa cultivation by explaining that they provided crops “even when no rain fell from the sky.”13
The aquatic gardens offered yet more advantages. The threat of frost, for instance, was reduced because the water helped to raise air and crop temperatures by a few degrees; in the evenings, the cooling air and the heat transfer of the relatively warm water in the canals allowed for a rise in humidity, which protected the plants. Furthermore, chinampas were periodically renewed with more vegetation, which helped the plot retain moisture, and the addition of freshly scooped muck from the lakebed helped to enrich the plots even as it allowed farmers to replace topsoil that had become increasingly saline—because of evaporation, the use of fertilizers, or other factors—with fresh deposits of earth. Thanks to mucking and mulching, among other ways of improving fertility, harvests were exceptionally high. One hectare of intensively cultivated chinampas could yield 3,000 kilograms of maize. This amount would be enough to support between 15 and 20 people at a subsistence level, if one were to allow for an average consumption of 160 kilos of maize per year for the dietary needs of a single person (according to modern dietary requirements for rural inhabitants of central Mexico). A single farmer could cultivate 0.75 ha of chinampa lands in each annual cycle. In other words, a single farmer could support 11 to 15 people.14
Agriculture and the Aztec Empire
Unsurprisingly, the rulers of the Aztec Triple Alliance took a keen interest in chinampa farming. The Mexica were particularly attentive to the chinampas’ abundance for the simple reason that they inhabited an island and, therefore, had only a limited amount of land. While some chinampas were built around the perimeter of Tenochtitlan, the city’s population could not have grown without a commensurate and widespread expansion of the area of land under cultivation. With much territory under the control of polities confined within the basin, the lakes were an ideal place to reclaim land for agriculture. The southern lakes of Xochimilco and Chalco were especially well suited to this kind of expansion: for one thing, they were consistently fed by natural springs and runoff as well as streams flowing down from the Sierra Nevada mountains; for another, they were shallow, typically between 1 and 3 meters deep, and most important, they were freshwater lakes. While other parts of the basin were home to chinampas, as with parts of Lakes Tetzcoco, Xaltocan, and Zumpango, the salinity and depth of their waters rendered them poorly suited to extensive chinampa agriculture. The southern lakes, then, became the focus for a colossal state-sponsored project to convert lakes into prime agricultural land.15
At once a vast land reclamation project and an enormous engineering program—comparable in scale to the draining of the fens in East Anglia or the Dutch polders—the transformation of the southern lakes into an agricultural landscape required a centrally planned and concerted effort. Indeed, the state-planned engineering program had to confront the hydrology of the Basin of Mexico’s lacustrine system as a whole. The entire irrigation network was designed to manage the natural flow of water that, left in an unaltered state, ebbed and flowed according to the season, shifting from marshy to free-flowing waters; lake levels themselves also varied considerably, and, with flooding, the five lakes that remained separate in the dry season could quickly be transformed into a single, great body of water. In Lake Xochimilco the movement of water was especially complicated: because the lake lay at a higher elevation than its neighbors, water typically flowed west and north, toward Lake Tetzcoco during the monsoon season; in the dry season, though, its flow reversed, and the water moved east and into Lake Chalco. In both of these scenarios, engineering works were needed to restrict the flow of water and to stabilize the lakes’ levels. To accomplish all this, in the 15th century the Aztec administration drew on the expertise of specialist, imperial engineers, and recruited tens of thousands of workers who built mile after mile of embankments, dikes, causeways, bridges, sluicegates, locks, ditches, canals, and aqueducts. The central feature of the Aztec water control system was the dike, or albarradón, in Lake Tetzcoco commissioned in the 1440s under the auspices of the emperor Moteucçoma I and the famous ruler of Tetzcoco, Neçahualcoyotl. In addition to protecting the island capital from floods, the Neçahualcoyotl dike, as it came to be known, further limited the potential for the brackish, saline waters of Lake Tetzcoco entering Lakes Xochimilco and Chalco, thereby jeopardizing the freshwater chinampas. Further embankments and sluicegates were built at two further locations in the southern lakes, at Mexicalzingo (where Lakes Xochimilco and Tetzcoco met) and at Tlahuac (the intersection between Lakes Xochimilco and Chalco).16
After sealing off the southern lakes and taking control of their hydrology, Nahuas set about converting the watery landscape into a new zone of densely packed chinampas. Remarkably, Nahuas seem to have completed the work in just a couple of generations. During that time local residents were granted a good deal of latitude in laying out and constructing the raised fields. As a result of this decentralized administration, some of the chinampas might have different shapes or be lined up in irregular formations. But because the overall design of the system was overseen by the central government, and given the need to maximize the available space, many chinampas were arranged in a neat, symmetrical, and regular order, much like modern city blocks, with canals serving as the equivalents of streets (this layout can be seen in two pictorial documents of Mexico City, dating to 1565, the Beinecke Map and the Plano Parcial de la Ciudad de México, see the links to digital sources). The longest chinampas and their adjacent canals were laid out in a common orientation, rotated to a few degrees east of true north. Intriguingly, this orientation mirrored that of the streets of Teotihuacan. Some have speculated that this alignment was chosen for astrological reasons.17
In a matter of a few decades, then, Nahuas turned the southern lakes into a large zone of fertile, raised fields that covered at least ten thousand hectares. To put that figure in perspective, the chinampa districts were the equivalent of more than 15,500 association football (soccer) pitches or approximately 18,750 National Football League (NFL) fields.18 So large were the overall chinampa districts that Nahuas took up residence on the artificial islands rather than remain on the shore. As one Spaniard writing in the 16th century observed, “A large number of Indians dwell inside the lagoon; they make staked enclosures and fill these with earth to some height above the water, and built their houses on top.”19 The lake became home to innumerable households and farmsteads, as well as dozens of hamlets, some of which may have been commercial hubs with markets and docking facilities for canoes. Canoes were another technological innovation that promoted the rise of wetland agriculture. Besides allowing for great mobility around the chinampa districts, farmers could use them for the making and upkeep of irrigation works, as well as the construction and cultivation of their gardens. Merchants, meanwhile, could reach markets quickly and efficiently, thereby helping to integrate the chinampa districts and tie them to the wider regional economy.20
The chinampa districts must have made for an impressive sight for Spanish conquistadors as they first crossed the Sierra Nevada mountains and looked down into the Basin of Mexico, especially because the districts were so densely populated. When counting shoreline settlements as well as towns and cities like Tlahuac and Xochimilco—which were situated on islands in the lake—there may have been tens of thousands of residents in the chinampa zone on the eve of the Spanish conquest. Perhaps as many as 30,000 Nahuas lived on reclaimed land in the lakes. The conquistador Bernal Díaz del Castillo wrote that Xochimilco was “a great city where nearly all the houses are built in a freshwater lake.” Similarly, Fernando Cortés related in his letters to the Spanish king the “sight of a pleasant city called Suchimilco, which is built on the freshwater lake.” In one of the most famous and oft-quoted passages of his Discovery and Conquest of Mexico, Bernal Díaz expressed a sense of wonder at the panorama: “when we saw so many cities and villages built in the water and other great towns on dry land and that straight and level causeway going to Mexico, we were amazed and said it was like the enchantments they tell of in the legends of Amadis, on account of the great towers and cues and buildings rising from the water.” He further marveled, “Gazing on such wonderful sights, we did not know what to say, or whether what appeared before us was real, for on one side, on the land, there were great cities, and in the lake ever so many more.”21
The combination of a large population and a landscape of richly productive agricultural gardens made for substantial food surpluses that supported the rise of the Aztec Empire. According to one conservative calculation, the chinampa farmers could have grown enough food to feed the 30,000 residents of the lakes and another 50,000 people elsewhere. Using a different methodology to compute the carrying capacity of the chinampas, another scholar reckoned that 12,700 farmers could generate annual harvests of 28,500,000 kilos of maize. That abundance would have been enough to feed some 140,000 people, effectively making possible the rise of Tenochtitlan as one of the greatest cities of the early modern world.22
Agriculture and the Spanish Empire
The defeat of the Mexica by Spaniards and their many Native allies was accompanied by the destruction of many of the engineering works that regulated the basin’s waters. The causeways leading to the capital, for instance, were deliberately breached during the final siege of Tenochtitlan. Other features of the water management system also fell victim to warfare. Fighting in the southern lake areas around Xochimilco caused untold damage, destroying dikes and, with flooding, laying waste to swathes of the aquatic countryside. The destruction did not end with the cessation of hostilities. Some chinampas districts survived the conquest only to succumb later to a slow process of disintegration: with the loss of centralized control over the flood defenses and the irrigation infrastructure, some of the engineering works fell into disrepair; with catastrophic population collapse, in the wake of the smallpox and other epidemics of the early colonial period, large portions of the lakebed chinampa zone fell into disuse and were abandoned. As the dikes and ditches slowly fell apart, so the chinampas gradually collapsed. In places the lakes reverted back into their earlier states as marshlands or shallow waters.23
The chinampa areas most drastically affected by these post-conquest environmental changes were those created under the aegis of the Aztec administration in the 15th century. The chinampa zone receded back toward the lakeshores, away from the middle of the lakes. By contrast, the chinampa districts located along the lakeshore, which radiated out from the island towns of Xochimilco, Mixquic, and Tlahuac, proved to be far more resilient. The persistence of these clusters of chinampas, which had long pre-dated the Aztec ecological interventions, can be attributed to several factors: they did not depend as much on the water control infrastructure as did the late Aztec-era chinampas; they escaped the worst of the flooding because they were typically located in shallower waters; also, the barriers at Mexicalzingo and Tlahuac remained sufficiently intact as to enable the continued cultivation of chinampas. In addition, sizable polities such as Xochimilco continued to devote considerable resources to the upkeep of the embankments, canals, and other features of the irrigation system in their jurisdictions. And, the chinampas remained highly fertile, continued to be a source of relative prosperity, and long remained crucial to the provisioning of Mexico City—which gave Nahuas some leverage in their legal and political dealings with the Spanish colonial administration, for instance, in protecting land from alienation by outsiders.
Over the course of the colonial period, chinampa agriculture underwent several changes. With less scrupulous supervision, the plots might increasingly be arranged in a haphazard or uneven fashion. As Raúl Avila López has shown for Iztapalapa, some chinampas apparently became larger over time. To a remarkable extent, they remained in the hands of indigenous peoples, though, and only in the late colonial period did haciendas, or large, landed estates, begin to intrude in the lake areas, at times upsetting the hydraulic balance of chinampa districts by pushing farther into the lake by reclaiming land. But, for the most part, Spaniards were reluctant to adopt the complex and intricate farming techniques of the lake districts, if only because they were too labor-intensive. The chinampas were thus ill-suited to seizure by outsiders.24
In some respects, the changing post-conquest situation afforded new opportunities for Nahua farmers. The introduction of new kinds of livestock—beyond the old, domesticated Mesoamerican animals such as turkeys, dogs, and bees—meant that some of the chinampas that had fallen vacant could be put to productive use as pastures, at least until residents were ready to return their chinampas to normal horticultural uses. Farmers preferred not to squander the great potential of the raised gardens on raising livestock, but newly introduced foreign animals such as cattle, horses, and mules as well as chicken, pigs, and goats provided opportunities for supplementary household income when sold in local markets, and the animals produced manure that farmers could use to fertilize fields. Additionally, the chinampa districts’ incorporation into the wider world of international trade and biological exchange brought with it the arrival of exotic plants. Many “old world” plants flourished on the chinampas. Nahuas now turned to raising broad beans and peas, as well as other vegetables that were well suited to high levels of moisture, among them carrots, lettuce, cabbage, radishes, beets, and onions. Beyond the riches of these plants were the flowers raised by farmers for sale in the capital and for the adornment of churches and homes across the region (in Nahuatl Xochimilco means “The Place of the Flower Fields.”) Among the commonly grown flowers were carnations, marigolds, roses, larkspurs, broom, dahlias, and lilies. By the end of the colonial period, when Alexander von Humboldt toured the chinampa region, the famous naturalist also recorded the cultivation of potatoes, artichokes, cauliflowers, and “an infinity of some other vegetables.” Nahuas, then, continued to harvest their old crops even as they incorporated foreign species. The historian Teresa Rojas Rabiela argued that the very diversity of plants raised by chinampa cultivators prior to the conquest assisted in the adoption of foreign species. She concluded that rather than signifying a process of substitution or displacement, imported species instead complemented and enriched chinampa cultivation.25
The post-conquest history of Xochimilco and the chinampa districts, therefore, is not just one of decline; rather, it is also one of adaptation, with the adoption of new farming techniques and new flora and fauna. That colonial-era history is also one of surprising resilience. Toward the end of the period of Spanish rule observers such as Humboldt and the creole polymath, José Antonio de Alzate y Ramírez, found much to admire in chinampa cultivation. In the 1790s Alzate published an admiring, highly laudatory, and detailed account of chinampa agriculture. He argued that the chinampas were not only a source of patriotic pride but also a vindication of the achievements of Mexico’s indigenous peoples. Alzate y Ramírez maintained that chinampa cultivation ought to be better known in other parts of the world because, if readers elsewhere were to adopt the novel and arguably superior farming techniques of Indians, they would be sure to enjoy fewer failed harvests, larger yields, and greater prosperity. It is worth dwelling on the significance of Alzate’s words: here was one of the most important intellectuals of the age—a thinker whose contributions to the Enlightenment has yet to be properly recognized, as with many of his compatriots across Latin America—extolling the virtues of indigenous people’s inventiveness and industry at a time when Indians were commonly denigrated and dismissed for their supposedly inferior, backward technology. In contrast to the common idea of technological change flowing from Europe to the Americas, here was a creole Spaniard arguing that the rest of the world should adopt an indigenous innovation in order to alleviate hunger and prevent famine. In a sense, Alzate’s advocacy proved prescient, albeit in a slightly tangential way: today, maize has come to be one of the most widely consumed staples around the world; millions of lives in Africa and elsewhere now depend on maize harvests.26
In the two centuries since Mexico’s independence, residents of Xochimilco and other lake area towns have continued to cultivate chinampas according to old methods even as they have adjusted to new circumstances. Mexico has remained at the forefront of technological changes in agricultural production, from the rise of monoculture export industries in the 19th century—with sugar, vanilla, cacao, coffee, and henequen serving as cash crops—to the emergence of industrial agriculture, with the use of pesticides and herbicides, and the 20th century’s Green Revolution. Chinampa farmers have responded to these and other changes by making use of chemical fertilizers, utilizing metal boats (alongside their old wooden canoes), covering crops with plastic tarps so as to protect them against frost, and employing gas-powered pumps to supply the chinampas with water recovered from Mexico City. These pumps have become ever more important since the notorious desagüe, or drainage project—begun during the colonial period but revived during the Porfiriato—led to widespread desiccation of the basin in the 20th century. Only a few hectares of the lacustrine landscape remain today, and they are located in and around Xochimilco. As part of efforts to protect what is left of the old lake environment, and to recognize indigenous people’s remarkable accomplishments in adapting to the watery landscape, in 1987 UNESCO designated Xochimilco a World Heritage Site.27
Discussion of the Literature
Initial studies of chinampas, as part of wider scholarship on Native agriculture in the Americas, were pioneered by geographers and anthropologists, with archaeologists prominent among them. Much of the impetus for early studies came from a new generation of anthropologists working from the 1940s. These scholars included Ángel Palerm, Pedro Armillas, Eric Wolf, and Paul Kirchhoff. Several of them had fled Europe in the previous decade, finding in Mexico not just sanctuary but also institutional support and the inspiration, from the country’s impressive archaeological sites, to pursue their studies. They tended to espouse a cultural materialist approach to understanding Native American societies and, as a result, they opened up new areas of investigation, particularly the connections between agriculture, irrigation systems, and the rise of urban centers.28 A separate scholarly genealogy can be traced back to Carl O. Sauer and the Berkeley School of Historical Geography. The interest of geographers such as William E. Doolittle in changes to landscapes at times dovetailed with the work of archaeologists.
Beyond their many scholarly contributions, these anthropologists and geographers did much to guarantee the growth and elaboration of the field. For one thing, they trained a second generation of scholars, among them Teresa Rojas Rabiela, William T. Sanders, and Andrew Sluyter. And they also helped to ensure stronger institutional support for scholarship, developing programs at major universities and founding new research institutions such as CIESAS, the Centro de Investigaciones y Estudios Superiores en Antropología Social in Mexico. The scholarship generated under the auspices of these institutions and by the new cohort of academics became increasingly interdisciplinary. This trend was extended further with the new contributions of historians, particularly ethnohistorians such as Rojas Rabiela, whose studies of chinampas remain unsurpassed to this day.
The single greatest repository for manuscript materials on chinampa agriculture is the Archivo General de la Nación in Mexico City. The most substantial and richest sets of historical documents can be found in this archive’s Tierras and Vínculos y Mayorazgos collections. Further material can be found in the Civil, Hospital de Jesús, Indios, and Indiferente Virreinal collections. The documents consist of administrative sources—from government reports to inspections and land grants—as well as the records of litigation, many of which had notarial sources inserted or copied into them as part of the judicial proceedings. Among these materials are a good many Nahuatl-language sources, especially last wills and testaments. The greatest number of these sources is to be found in the AGN’s Tierras collection. The best way to track down these documents is to use the AGN’s collection guides and, besides searching for key terms like chinampas and camellones as well as lagunas (lakes) and ciénagas (marshes or swamps), prospective researchers can browse the sources pertaining to chinampa towns, especially Ayotzinco, Coyoacan, Culhuacan, Ixtapalapa, Mexicalzingo, Mixquic, Tlahuac, and Xochimilco. Additional materials may be found in other repositories, including Mexico City’s notarial archives and Seville’s Archivo General de Indias.
Acosta, José de. Natural and Moral History of the Indies. Edited by Jane E. Mangan. Translated by Frances M. López-Morillas. Durham, NC: Duke University Press, 2002.Find this resource:
Alzate y Ramírez, José Antonio de. “Memoria sobre agricultura.” Gacetas de literatura de México, tomo 2. Puebla: Reimpresa en la oficina del Hospital de S. Pedro, 1831, 382–399.Find this resource:
Cline, Sarah, and Miguel León Portilla. The Testaments of Culhuacan. Los Angeles: Latin American Center Publications, University of California, Los Angeles, 1984.Find this resource:
Humboldt, Alejandro de. Ensayo Político sobre el reino de la Nueva España. Mexico City: Porrua, 1966.Find this resource:
Links to Digital Materials
Archivo General de la Nación, Mexico City.
Archivo General de Notarías, Mexico City.
Portal de Archivos Españoles, including Seville’s Archivo General de Indias.
Beinecke Map (Codex Reese), Beinecke Rare Book & Manuscript Library, Yale University.
Mapa de San Pedro Tlahuac, 1656; Plano de Chinampas en Tlahuac; and Plano de Chinampas en Xochimilco, from the “The Mapas Project,” Stephanie Wood, editor, at the University of Oregon (with the original maps from the Archivo General de la Nación, Mexico City).
Testaments of Culhuacan, an unpublished, revised version of the 1984 anthology.
Armillas, Pedro. “Gardens on Swamps.” Science 174.4010 (November 12, 1971): 653–661.Find this resource:
Avila López, Raúl. Chinampas de Iztapalapa, D. F. Mexico City: Instituto Nacional de Antropología e Historia, 1991.Find this resource:
Coe, Michael D. “The Chinampas of Mexico.” Scientific American 121.1 (July 1964): 90–98.Find this resource:
Frederick, Charles D. “Chinampa Cultivation in the Basin of Mexico: Observations on the Evolution of Form and Function.” In Seeking a Richer Harvest: The Archaeology of Subsistence, Intensification, Innovation, and Change. Edited by Tina L. Thurston and Christopher T. Fisher, 117–124. New York: Springer Science + Business Media, 2007.Find this resource:
Luna Golya, Gregory. “Modeling the Aztec Agricultural Waterscape of Lake Xochimilco: A GIS Analysis of Lakebed Chinampas and Settlement.” PhD diss., Pennsylvania State University, 2014.Find this resource:
Mundy, Barbara E. The Death of Aztec Tenochtitlan, The Life of Mexico City. Austin: University of Texas Press, 2015.Find this resource:
Outerbridge, Thomas. “The Disappearing Chinampas of Xochimilco.” Ecologist 17.2–3 (March/June 1987): 76–83.Find this resource:
Palerm, Ángel. Obras hidráulicas prehispánicas en el sistema lacustre del Valle de México. Mexico City: Instituto Nacional de Antropología e Historia, 1973.Find this resource:
Parsons, Jeffrey R., Mary H. Parsons, Virginia Popper, and Mary Taft. “Chinampa Agriculture and Aztec Urbanization in the Valley of Mexico.” In Prehistoric Intensive Agriculture. Edited by I. S. Farrington, 49–96. Oxford: B.A.R., 1985.Find this resource:
Rojas Rabiela, Teresa. “La tecnología indígena de construcción de chinampas en la Cuenca de México.” Civilización 2 (1984): 13–48.Find this resource:
Rojas Rabiela, Teresa. Las siembras de ayer: La agricultura indígena del siglo XVI. Mexico City: Centro de Investigaciones y Estudios Superiores en Antroplogía Social, 1988.Find this resource:
Rojas Rabiela, Teresa. “Ecological and Agricultural Changes in the Chinampas of Xochimilco-Chalco.” In Land and Politics in the Valley of Mexico: A Two Thousand Year Perspective. Edited by H. R. Harvey, 275–290. Albuquerque: University of New Mexico Press, 1991.Find this resource:
Rojas Rabiela, Teresa, ed. La agricultura chinampera: compilación histórica. Mexico City: Universidad Autónoma Chapingo, 1993.Find this resource:
Sanders, William T., Jeffrey R. Parsons, and Robert S. Santley. The Basin of Mexico: Ecological Processes in the Evolution of a Civilization. New York: Academic Press, 1979.Find this resource:
Wilken, Gene C. “A Note on Buoyancy and Other Dubious Characteristics of the ‘Floating’ Chinampas of Mexico.” In Prehistoric Intensive Agriculture in the Tropics vol. 1. Edited by I. S. Farrington, 31–48. Oxford: B.A.R., 1985.Find this resource:
(1.) John E. Clark, The Lithic Artifacts of La Libertad, Chiapas, Mexico: An Economic Perspective, Papers of the New World Archaeological Foundation, vol. 52 (Provo, UT: New World Archaeological Foundation, Brigham Young University, 1988); Lorena Mirambell, Técnicas Lapidarias Prehispánicos (Mexico City: Instituto Nacional de Antropología e Historia, 1968); Dorothy Hosler, The Sounds and Colors of Power: The Sacred Metallurgical Technology of Ancient West Mexico (Cambridge, MA: MIT Press, 1994); Bruce D. Smith, The Emergence of Agriculture (New York: Scientific American Library, 1998); and Luis A. Barba and José Luis Córdova Frunz, “Estudios energéticos de la producción de cal en tiempos teotihuacanos y sus implicaciones,” Latin American Antiquity 10, no. 2 (June 1999): 168–179.
(2.) Bruce F. Benz and Austin Long, “Prehistoric Maize Evolution in the Tehuacan Valley,” Current Anthropology 41 (2000): 459–465; Janet Long-Solís, Capsicum y cultura: La historia del chilli (Mexico City: Fondo de Cultura Económica, 1998); Bruce D. Smith, “Initial Domestication of Curcubita pepo in the Americas 10,000 Years Ago,” Science 276 (1997): 932–934; Sissel Johannessen and Christine A. Hastorf, Corn and Culture in the Prehistoric New World (Boulder, CO: Westview, 1994); John F. Doebley, “Molecular Evidence and the Evolution of Maize,” Economic Botany 44, no. 3 (1990): 6–27; Paul Tolstoy, S. Fish, M. Boksenbaum, and K. Vaughn, “Early Sedentary Communities of the Basin of Mexico,” Journal of Field Archaeology 4 (1977): 91–106; Richard S. MacNeish, “The Food Gathering and Incipient Agriculture Stage of Prehistoric Middle America,” in Handbook of Middle American Indians, ed. Robert C. West and Robert Wauchope (Austin: The University of Texas Press, 1964), 1:413–426; Paul C. Mangelsdorf, Richard S. MacNeish, and Gordon R. Willey, “Origins of Agriculture in Middle America,” in Handbook of Middle American Indians, ed. Robert C. West and Robert Wauchope, 1:427–445; and Sophie Coe, America’s First Cuisines (Austin: University of Texas Press, 1994).
(3.) Alfred Siemens and Dennis E. Puleston, “Ridged Fields and Associated Features in Southern Campeche: New Perspectives on the Lowland Maya,” American Antiquity 37, no. 2 (1972): 228–239; Scott L. Fedick, ed., The Managed Mosaic: Ancient Maya Agriculture and Resource Use (Salt Lake City: University of Utah Press, 1996); Robert J. Sharer, The Ancient Maya (Stanford, CA: Stanford University Press, 1994); Teresa Rojas Rabiela, Las siembras de ayer: La agricultura indígena del siglo XVI (Mexico City: Secretaría de Educación Pública and Centro de Investigaciones y Estudios Superiores en Antropologia Social, 1988); and Rojas Rabiela, Agricultura indígena, pasado y presente (Mexico City: Centro de Investigaciones y Estudios Superiores en Antropología Social, 1990).
(4.) Andrew Sluyter, “Intensive Wetland Agriculture in Mesoamerica: Space, Time and Form,” Annals of the Association of American Geographers 84, no. 4 (1994): 557–584; William E. Doolittle, Canal Irrigation in Prehistoric Mexico: The Sequence of Technological Change (Austin: The University of Texas Press, 1990); William T. Sanders, Jeffrey R. Parsons, and Robert S. Santley, The Basin of Mexico: Ecological Processes in the Evolution of a Civilization (New York: Academic Press, 1979); and Alfred H. Siemens, Tierra configurada. Investigaciones de los vestigios de agricultura precolombina en tierras inundables costeras desde el norte de Veracruz hasta Belice (Mexico City: Consejo Nacional para la Cultura y las Artes, 1989).
(5.) When the term is translated into Spanish, it includes the locative –pan in place of the noun ending –itl, hence chinampan (with the final consonant having been dropped).
(6.) Teresa Rojas Rabiela, “Ecological and Agricultural Changes in the Chinampas of Xochimilco-Chalco,” in Land and Politics in the Valley of Mexico: A Two Thousand Year Perspective, ed. H. R. Harvey (Albuquerque: University of New Mexico Press, 1991), 276; Sanders, et al., The Basin of Mexico, 281; Charles D. Frederick, “Chinampa Cultivation in the Basin of Mexico: Observations on the Evolution of Form and Function,” in Seeking a Richer Harvest: The Archaeology of Subsistence, Intensification, Innovation, and Change, ed. Tina L. Thurston and Christopher T. Fisher (New York: Springer Science + Business Media, 2007), 120; Gregory Luna Golya, “Modeling the Aztec Agricultural Waterscape of Lake Xochimilco: A GIS Analysis of Lakebed Chinampas and Settlement” (PhD diss., Pennsylvania State University, 2014), 66; Earle C. Smith and Paul Tolstoy, “Vegetation and Man in the Basin of Mexico,” Economic Botany 35, no. 4 (1981): 415–433; and Tolstoy, “Settlement and Population Trends in the Basin of Mexico (Ixtapaluca and Zacatenco Phases),” Journal of Field Archaeology 2, no. 4 (1975): 331–349.
(7.) Jeffrey R. Parsons, Mary H. Parsons, Virginia Popper, and Mary Taft, “Chinampa Agriculture and Aztec Urbanization in the Valley of Mexico,” in Prehistoric Intensive Agriculture, ed. I. S. Farrington, 52; Parsons, “The Role of Chinampa Agriculture in the Food Supply of Aztec Tenochtitlan”; Ángel Palerm, Obras hidráulicas prehispánicas en el sistema lacustre del Valle de México (Mexico City: Instituto Nacional de Antropología e Historia, 1973); and Luna, “Modeling the Aztec Agricultural Waterscape of Lake Xochimilco,” 7, 49, and 63–66.
(8.) Palerm, Obras hidráulicas prehispánicas; Parsons, et al., “Chinampa Agriculture and Aztec Urbanization in the Valley of Mexico,” 88; and Luna, “Modeling the Aztec Agricultural Waterscape of Lake Xochimilco,” 7 and 70.
(9.) Wilken, “A Note on the Buoyancy and Other Dubious Characteristics of the ‘Floating’ Gardens of Mexico,” 35–39; Parsons, et al., “Chinampa Agriculture and Aztec Urbanization in the Valley of Mexico,” 88; Rojas Rabiela, “Aspectos tecnológicos de las obras hydráulicas coloniales,” in Nuevas noticias sobre las obras hidráulicas prehispánicas y coloniales en el Valley de México, ed. Teresa Rojas Rabiela, R. Strauss, and J. Lameiras (México: Instituto Nacional de Antropología e Historia, 1974), 56–57.
(10.) Sanders et. al., The Basin of Mexico, 51; Rojas Rabiela, “Ecological and Agricultural Changes in the Chinampas of Xochimilco-Chalco,” 281; Wilken, “A Note on Buoyancy and Other Dubious Characteristics of the ‘Floating’ Chinampas of Mexico,” 34–35; Frederick, “Chinampa Cultivation in the Basin of Mexico,” 117; Luna, “Modeling the Aztec Agricultural Waterscape of Lake Xochimilco,” 6; and Pedro Armillas, “Gardens on Swamps,” Science 174, no. 4010 (November 12, 1971): 654.
(11.) Rojas Rabiela, “Ecological and Agricultural Changes in the Chinampas of Xochimilco-Chalco,” 280–281; Ross Hassig, Trade, Tribute, and Transportation: The Sixteenth-Century Political Economy of the Valley of Mexico (Norman: University of Oklahoma Press, 1985), 47; Sanders et al., The Basin of Mexico, 277; Thomas Outerbridge, “The Disappearing Chinampas of Xochimilco,” Ecologist 17, no. 2–3 (March/June 1987): 76–83; and Luna, “Modeling the Aztec Agricultural Waterscape of Lake Xochimilco,” 118–120.
(12.) Frederick, “Chinampa Cultivation in the Basin of Mexico,” 114; Charles Gibson, The Aztecs under Spanish Rule: A History of the Indians of the Valley of Mexico, 1519–1810 (Stanford, CA: Stanford University Press, 1964), 321; Coe, “The Chinampas of Mexico,” 95. Rojas Rabiela, “Ecological and Agricultural Changes in the Chinampas of Xochimilco-Chalco,” 285; and Armillas, “Gardens on Swamps,” 654.
(13.) Armillas, “Gardens on Swamps,” 653–654; Luna, “Modeling the Aztec Agricultural Waterscape of Lake Xochimilco,” 25; and Archivo General de Indias, Seville, Audiencia de México, Legajo 227, no. 17, f. 1v.
(14.) Luna, “Modeling the Aztec Agricultural Waterscape of Lake Xochimilco,” 61, 120, 153, and 156–157; Parsons, “The Role of Chinampa Agriculture in the Food Supply of Aztec Tenochtitlan,” 242, 245; and Parsons et al., “Chinampa Agriculture and Aztec Urbanization in the Valley of Mexico,” 51.
(15.) Christopher T. Morehart, “Mapping Ancient Chinampa Landscapes in the Basin of Mexico: A Remote Sensing and GIS Approach,” Journal of Archaeological Science 39 (2012): 2541–2551; Morehart and Daniel T. A. Esienberg, “Prosperity, Power, and Change: Modeling Maize at Postclassic Xaltocan, Mexico,” Journal of Anthropological Archaeology 29 (2010): 94–112; Sanders, et al., The Basin of Mexico, 280; and Palerm, Obras hidráulicas prehispánicas; Armillas, “Gardens on Swamps,” 660. The scale of this project inspired Karl Wittfogel to include the Aztecs in his theories about hydraulic societies and “Oriental despotism.” See Karl Wittfogel, Oriental Despotism: A Comparative Study of Total Power (New Haven, CT: Yale University Press, 1957); and “Developmental Aspects of Hydraulic Societies,” in Irrigation Civilizations: A Comparative Study—A Symposium on Method and Result in Cross-Cultural Regularities, ed. J. Steward (Washington, DC: Pan American Union Social Science Monographs 1, 1955), 28–42. See also Ángel Palerm, Agua y agricultura: Ángel Palerm, la discusión con Karl Wittfogel sobre el modo asiático de producción y la construcción de un modelo para el estudio de Mesoamérica (Mexico City: Universidad Iberoamericana and Agencia Española de Cooperación Internacional, Dirección General de Relaciones Culturales y Científicas, 2007).
(16.) Barbara Mundy cites a 16th-century codex that referred to 50,000 soldiers working on Nezhualcoyotl’s dike. Barbara E. Mundy, The Death of Aztec Tenochtitlan, The Life of Mexico City (Austin: University of Texas Press, 2015), 34–39; Margarita Carballal Staedtler and María Flores Hernández, “Hydraulic Features of the Mexico-Texcoco Lakes during the Postclassic Period,” in Precolumbian Water Management, ed. L. J. Lucero and B. W. Fash (Tucson: University of Arizona Press, 2006), 155–170; Luna, “Modeling the Aztec Agricultural Waterscape of Lake Xochimilco,” 41, 63; and Coe, “The Chinampas of Mexico,” 92–93 and 98. See also Wilken, “A Note on Buoyancy and Other Dubious Characteristics of the ‘Floating’ Gardens of Mexico,” 39. For a description of water management systems in the chinampa areas, see Parsons, et al., “Chinampa Agriculture and Aztec Urbanization in the Valley of Mexico,” 88.
(17.) Frederick, “Chinampa Cultivation in the Basin of Mexico,” 120; Mundy, The Death of Aztec Tenochtitlan, 78; Coe, “The Chinampas of Mexico,” 96–97; Edward E. Calnek, “Settlement Pattern and Chinampa Agriculture at Tenochtitlan,” American Antiquity 37, no. 1 (January 1972): 104–115; and Armillas, “Gardens on Swamps,” 658–660.
(18.) These figures are calculated according to the official minimum lengths of the pitch used in international soccer matches (100 m for the touchline, 64 m for the goal-line) and the official size of fields in NFL games (120 yards in length, 53.33 yards in width). Since the soccer pitch would be a minimum of 6,400 m2 and with a hectare equaling 10,000 m2, 10,000 hectares are the equivalent of 15,625 football pitches. For association football field sizes, see www.fifa.com and www.thefa.com. The calculation of the equivalent number of NFL fields requires a conversion of hectares into acres: since there are approximately 2.47 acres in a hectare, the 10,000 hectares are the equivalent to 24,700 acres. An acre is 4,840 square yards, which means that the chinampa districts covered approximately 120,000,000 acres. Because an NFL field is 6,399.6 square yards in area, the equivalent number of fields is roughly 18,750. For NFL field sizes, see www.nfl.com.
(19.) The quotation is by Bernardo de Vargas Machuca, cited in Armillas, “Gardens on Swamps,” 660.
(20.) Luna, “Modeling the Aztec Agricultural Waterscape of Lake Xochimilco,” 141–145; and Richard Conway, “Lakes, Canoes, and the Aquatic Communities of Xochimilco and Chalco, New Spain,” Ethnohistory 59, no. 3 (2012): 541–568.
(21.) Parsons, et al., “Chinampa Agriculture and Aztec Urbanization in the Valley of Mexico,” 52; Luna, “Modeling the Aztec Agricultural Waterscape of Lake Xochimilco,” iv and 148; Hernán Cortés, Letters from Mexico, ed. and trans. Anthony Pagden (New Haven, CT: Yale University Press, 1986), 190, 198–199; and Bernal Díaz del Castillo, The Discovery and Conquest of Mexico, 1517–1521, trans. A. P. Maudslay (New York: Farrar, Strauss, and Cudahy, 1956), 192 and 377.
(22.) Parsons, “The Role of Chinampa Agriculture in the Food Supply of Aztec Tenochtitlan,” 242, 245; and Luna, “Modeling the Aztec Agricultural Waterscape of Lake Xochimilco,” iv, 148, 160;
(23.) Vera S. Candiani, Dreaming of Dry Land: Environmental Transformation in Colonial Mexico City (Stanford, CA: Stanford University Press, 2014), 15–45; Luna, “Modeling the Aztec Agricultural Waterscape of Lake Xochimilco,” 25–26, 74; Rojas Rabiela, “Ecological and Agricultural Changes in the Chinampas of Xochimilco-Chalco,” 288; and Mundy, The Death of Aztec Tenochtitlan, 75.
(24.) Richard Conway, “Nahuas and Spaniards in the Socioeconomic History of Xochimilco, New Spain, 1550–1725” (PhD diss., Tulane University, 2009); Luna, “Modeling the Aztec Agricultural Waterscape of Lake Xochimilco,” 173–174; and Raúl Avila López, Chinampas de Iztapalapa, D. F. (México: Instituto Nacional de Antropología e Historia, 1991).
(25.) Rojas Rabiela, “Ecological and Agricultural Changes in the Chinampas of Xochimilco-Chalco,” 281–283; and Conway, “Nahuas and Spaniards,” 62–86.
(26.) James C. McCann, Maize and Grace: Africa’s Encounter with a New World Crop, 1500–2000 (Cambridge, MA: Harvard University Press, 2007); José Antonio de Alzate y Ramírez, “Memoria sobre agricultura,” Gacetas de literatura de México, vol. 2 (Puebla: reimpresa en la oficina del Hospital de S. Pedro, 1831), 382–399. Also published in Teresa Rojas Rabiela, ed., La agricultura chinampera: Compilación histórica (Mexico City: Universidad Autónoma Chapingo, 1993), 13–29; Jorge Cañizares-Esguerra, “Introduction” and Fiona Clark, “‘Read All about It’: Science, Translation, Adaptation, and Confrontation in the Gazeta de Literatura de México, 1788–1795,” in Science in the Spanish and Portuguese Empires, 1500–1800, ed. Daniela Bleichmar, Paula De Vos, and Kristin Huffine (Stanford, CA: Stanford University Press, 2009), 1–5 and 147–177; Jorge Cañizares-Esguerra, How to Write the History of the New World: History, Epistomologies, and Identities in the Eighteenth-Century Atlantic World (Stanford, CA: Stanford University Press, 2002), 266–345; and Cañizares-Esguerra, Nature, Empire, and Nation: Explorations in the History of Science in the Iberian World (Stanford, CA: Stanford University Press, 2006).
(27.) Cynthia Hewitt de Alcantara, Modernizing Mexican Agriculture: Socioeconomic Implications of Technological Change, 1940–1970 (Geneva, Switzerland: United Nations Research Institute for Social Development, 1976); Luna, “Modeling the Aztec Agricultural Waterscape of Lake Xochimilco,” iv; and Exequiel Ezcurra, De las chinampas a la megapolis: El medio ambiente en la cuenca de México (Mexico City: Fondo de Cultural Económica, 1991).
(28.) Ángel Palerm and Eric R. Wolf, Agricultura y civilización en Mesoamérica (Mexico City: Secretaría de Educación Pública, 1972); and Eric R. Wolf, ed., The Valley of Mexico: Studies in Prehispanic Ecology and Society (Albuquerque: University of New Mexico Press, 1976).