Full content for this article includes photograph and illustration.

Source: Americas (English Edition), Nov-Dec 1992 v44 n6 p6(10).

Title: Cultivating the secrets of Aztec gardens. (the floating gardens
of Xochimilco in Mexico)
Author: Louis Werner

Abstract: The floating gardens of Xochimilco in Mexico are remnants of an
Aztec agricultural system called 'Chinampa.' Chinampa is a farming system
based on swamp reclamation and canalization. Experts say that the system was
highly effective and produced abundant harvests.

Subjects: Mexico - Agriculture
Aztecs - History
Agricultural systems - Analysis
Locations: Mexico

Full Text COPYRIGHT 1992 Organization of American States

PRIMARILY A TOURIST ATTRACTION TODAY, THE FLOATING GARDENS OF XOCHIMILCO ARE
THE REMAINS OF AN INTRICATE AGRICULTURAL SYSTEM WHICH FED MEXICO'S ANCIENT
CAPITAL CITY

PRE-COLUMBIAN MEXICO presented the European world with an untold bounty of
newand sophisticated foods and flowers--maize, chiles, tomatoes and dahlias
toname but a few. At the height of the Aztec Empire, the agricultural
technology
which made possible this productivity was most advanced in the central
valley,a 3,000 square mile pancake-flat expanse containing five
interconnected lakes.
Remarkably, many of these ancient farming methods remain in use today and
still have much to teach us about feeding more people while showing more
respect for our environment. At a time when the twin requirements of
ecological protection and agricultural growth are so often at odds, and as
thenumber of the world's hungry continues to mount, we should listen closely
to
those who grow surplus food on farmlands they nurture as lovingly as their
crops.

Population estimates of the Aztec's island-capital of Tenochtitlan in 1520
range up to 200,000 people, with twice that number in the immediate area and
over one million in the entire valley. This population's density and size,
larger than any conurbation yet known to man, inspired Spanish chronicler
Bernal Diaz del Castillo's famous remarks upon first entering the valley,
"Andwhen we saw all those cities and villages built in the water and
other great
towns on dry land, and that straight and level causeway leading to
Tenochtitlan, we were amazed ... Indeed, some of our soldiers asked if it was
not all a dream."

The agricultural practice most responsible for feeding such numbers is the
chinampa system, a network of raised fields (camellones) on low man-made
islands in the middle of lakes and marshes. These raised farming beds are not
an Aztec invention. Earlier evidence is found in the nearby ancient city of
Teotihuacan and among the lowland Maya, as well as in Suriname's swamps and
Peru's Lake Titicaca. But it was under Aztec rule that they were most
extensively built and intensively cultivated.

Chinampa is derived from the Nauhatl words chinamitl, meaning "reed basket,"
and pan, meaning "upon," which aptly describes their building method. Lake
bedclays and muds, aquatic plants and dryland crop silage, and silted muck
andmanures were piled one upon another in precise layers between parallel
reedfences stuck in the lake bottom. Long fingers of dry ground alternated
with
narrow canals, from which the chinampa muds and mucks were dredged, in a
tightly laced configuration that resembled an endless water maze. Once the
ground was raised to its proper height, fast-growing willow trees (ahuejotes)
were planted at the banks' edges to control erosion, provide shade and
firewood, and impede the flow of crop-damaging pests. Chinampa farmers became
known as "chinampanecas," or simply as "chinamperos".

It is unclear how and why chinampas came to dominate the central valley. Some
anthropologists see it as only logical that a farming system based on swamp
reclamation and canalization should emerge in an area plagued by alternating
flood and drought conditions. Others see chinampa agriculture as a conceptual
breakthrough on a par with the Old World's invention of the wheel. Why have
roads and wheeled carts when the chinampas created a network of canals
throughwhich cargo and passenger canoes easily navigated? What is known,
however, is
that after the fall of the pyramid-city of Teotihuacan in the eighth century,
farming people were suddenly free to migrate throughout the valley. The
fresh,spring--fed waters of the southern lakes Xochimilco and Chalco, teeming
with
waterfowl, fish, and the tasty salamander-like axolotl, offered an
irresistible invitation. Xico Island was settled at this time and is one of
the first places in the area to show signs of chinampa construction.

By the fourteenth century, chinampas were the basis for the growth of the
independent tribe-ruled island states of Xochimilco, Chalco, Mixquic, and
Cuitlahuac near the two lakes' southern shores. The Xochimilcans soon became
the undisputed master chinampa builders; but being nearest the Aztec capital
in adjoining Lake Texcoco, they were also the first to bow to them in a
battlewhich is recounted in a bloodcurdling war annal. Chinampas covered some
20,000
hectares (45,000 acres) and in the two southern lakes. Lake Texcoco and the
two smaller northern lakes, Zumpango and Xaltocan, were too heavily salinated
and frequently flooded to warrant a major chinampa construction effort.

Earlier, however, after Tenochtitlan had been founded (in 1325) on an
uninhabited swampy island, it was expanded atop chinampa-like housing
platforms and eventually linked to the twin island of Tlatelolco. In the
fifteenth century, the Aztec king Montezuma I and his vassal prince, the
Texcocan poet-engineer Nezahualcoyotl, employed 20,000 men to build a ten
milestone dike ("albarradon de Nezahualcoyotl") across Lake Texcoco. This
mostadvanced feat of engineering, complete with sluice gates and drawbridges,
halted Tenochtitlan's flooding and lowered the lake's salinity. Its water
could then be used for more intensive irrigation, and so chinampa crops
ripened just steps from the central plaza. Nezahualcoyotl's experiments in
hydraulic engineering did not stop with his dike. On Texcoco's steep
hillsides, he combined the seemingly irreconcilable techniques of field
terracing and chinampa canalization, using aqueducts to bring irrigation
waterfrom distant sources. This self-sufficient, naturally fortified farming
system
thus helped his city-state maintain its quasi-independence.

Once the Aztecs completed their subjugation of the southern chinampa zone,
they forced these more peaceable tribes to sign treaties which read in part,
"We will go and serve in your homes and furnish you labor and food for all
your needs ... and wherever you go we will carry your loads. We will be your
subjects forever." With these words the Aztecs took control of the chinampas,
which quickly became the breadbasket to feed their armies. Xochimilcan and
Chalcan forced labor was put to work expanding their chinampas to supply
Tenochtitlan's burgeoning population. The fields were worked more intensively
and around the calendar year. Many refinements in chinampa farming practice
thus evolved under the Aztec fist. Necessity under these life-or-death
circumstances was truly the mother of invention. But free trade between the
southern lakes and Tenochtitlan also existed alongside these involuntary
tributes and rent collections.

Chinamperos economized labor wherever possible in order to increase their
overall productivity. The chinampas' low profile above water, their long and
narrow layout between parallel canals, and their layering of specific soil
types reduced the constant need for irrigation. The ground's capillary action
sucked sufficient amounts of canal water up and over to the roots of crops
cultivated on top. Nevertheless, the work was exceedingly labor intensive.
Chinamperos spent their day fertilizing, transplanting, and tending plant
nurseries. Their most common fertilizer was the compost of human waste and
aquatic plants cleaned from the canals. Chiles were cultivated with bat
guano,which was carried in by slave trains bearing baskets of the stuff from
the
caves of Morelos. Whenever maize was cultivated, ground hugging crops like
beans and squash were planted between the rows. Intercropping (policultive)
ofthis sort kept soil nutrients in balance. The root action and silage of
these
bushier plants returned to the earth the minerals consumed by the more
demanding maize crop.

The greatest innovation was the use of seed germination beds and seedling
nurseries (almacigas). These allowed chinamperos to concentrate care and
attention on crops at their most delicate stage. The beds were laid out at
thechinampa's edge and filled with the canal's rich and syrupy bottom muds,
dredged up with a long handled pole basket known as the zoquimaitl. This
luxuriant growth culture ensured germination and early vigor. When still
slightly damp, the mud around each seedling was cut into small cubes
(chapines) for transplanting whole. Weak seedlings were discarded, while some
slow-growing crops were transplanted twice before maturing to harvest.
Flowerssuch as cempoaxochitl (crow flower) were grown in their own beds,
while root
cubes of chiles were often sent off to be grown in the highlands.

The sixteenth century Franciscan missionary Bernardino de Sahagun compiled an
account of Aztec daily life from native informants, entitled "Historia
Generalde las Cosas de Nueva Espana," which included an extraordinarily
detailed list
of chinampa-grown plants. In addition to those already mentioned were green
tomato (jitomate), chia, amaranth, chayote, and chilacayote, as well as the
edible herbs uauhzontli, quiltonil, and quelite cenizo--all cultivated with
just one hand tool, the versatile broad-balded digging stick known as the
"coa" and still widely used by modern chinamperos.

The pre-Columbian chinampas' productivity was astoundingly high even by
today's standards. Estimated maize yields vary between three and five metric
tons per hectare. And two crops could be harvested in the same year. Still
today, chinampa harvests have been known to outweigh those from high-tech
agricultural research stations. (In 1986 it was a chinampero from Mixquic who
won his nation's annual maize growing contest.) The exact timing of
transplanting allowed for the optimal and proper use of the chinampas. Fields
were never left fallow, a fact we know from colonial farmers' almanacs. As
soon as one crop was harvested, another set of seedlings were put in place.
Scarce land was thus not tied up by long-cycle crops growing from seed. Up to
four harvests a year on the same plot were often possible. During the
fall/winter season, non-frost hardy plants were protected with mats (abrigos)
of straw and woven cattails.

When Hernan Cortes and his Spanish army first entered the valley in 1519, he
crossed the chinampa-lined causeway at Cuitlahuac and proceeded directly to
Tenochtitlan. While preparing to beseige the island capital two years later,
however, he took full control of these southern chinampas. In his letters to
Charles V, Cortes called Cuitlahuac "the best looking small city we have
seen," and noted Mixquic as "a small town, completely set upon water." The
first Spaniards to write about chinampas in detail were responsible for
launching the "floating garden" myth remaining to this day. Jose de Acosta,
author of the "Historia Natural y Moral de las Indias," wrote that chinampas
were towed from place to place like barges. Father Torquemada neglected to
repeat this tall tale in his three volume "Monarquia Indiana," but even the
clear-sighted geologist and naturalist Alexander von Humbolt was taken in by
the floating chinampa story after seeing buoyant mats of water hyacinth the
Spanish themselves had introduced.

Chinampero life survived the Conquest largely intact, due in most part to the
Xochimilcans' and Chalcans' cultural hardiness. But the Spanish, being
horsemen at heart, cared little for the hydrological talents of farmers and,
just as they did to the irrigation designs of the Moors, they sabotaged the
Aztec's finest water works in one way or another. In their most brazen act,
they stole stones from Nezahualcoyotl's great dike in order to erect their
colonial city upon Tenochtitlan's ruins. Not unexpectedly, terrible flooding
returned and continued to haunt the city until well into this century. The
Spaniards' answer to these floods, rather than simply to control the water as
the Aztecs had done, was to eliminate it altogether through a series of grand
but mostly ineffective drainage schemes. The chinampas might be emptied, they
reasoned, but the lake bottoms themselves would make rich farmland. Little
didthey care that the lakes were mostly saline, or that storms of noxious
ground
salts, wind-whipped like dust off the drying beds, would soon rival flooding
as Mexico City's worst natural scourge.

Lakes Xochimilco and Chalco, even though fed by underground springs, slowly
began to shrink and their chinampas to die of thirst over the following
centuries. The rivers supplementing Lake Chalco's fresh water
supply--Amecameca, Tenango, and Tlalmanalco--were diverted, and was dry by
1900 except in times of heavy rain. Of more dire consequence for the ever
shrinking chinampas was President Porfirio Diaz' decision to tap into
Xochimilco's largest springs--beginning with Nativitas and by 1930 including
La Noria, Acalpixca, and Tlaxiatemalco--in order to supply the fast growing
city with drinking water. Lake Xochimilico gradually began to contract. In
1950, a year with little rain, the chinampas turned bone dry.

Chinampero protests finally convinced officials to act, but their answer was
only to redirect semi-treated sewage water in through the Canal Nacional,
which inadvertently collected untreated industrial and household wastes.
Deteriorating water quality caused farmed acreage and crop diversity to
shrinkwhile water-born pathogens rose and soil productivity sank. By 1988,
only half
of the chinampas' remaining 2,300 hectares were actively farmed, and some
twenty useful plant species had disappeared in just two decades. Also slowly
sinking are the chinampas themselves, caused by pumping from deep-water wells
to increase the city's water supply even further. The northern district today
often floods while passenger boats in the chinampas' southern zone, now a
major tourist attraction, scrape bottom.

The current situation is of grave concern to Jose Genovevo Perez, a
chinamperoin Xochimilco's Pueblo de San Luis Tlaxialtemalco and leader of a
grassroots
chinampa preservation campaign. "We still don't get enough water to keep the
canals full, and the little we do get is still too dirty," he says. "I want
mythree sons to follow in my footsteps, to farm like my grandfathers did. But
I
worry that things are changing too fast for them." Jose is perhaps typical of
the modern chinampero, caught between his traditions and the reality
surrounding him. Some of his smaller plots have been consolidated for
cultivation by tractor, which allows greater economies of scale but also
destroys the soil characteristics making the chinampas unique. "But I also
cultivate by hand and with draft animals where I can. That's still best."
Joseis pleased that UNESCO declared Xochimilco a World Heritage Site in 1988,
an
honor which brings wider attention on the chinamperos' plight and spurred the
government recently to launch the Ecological Rescue Plan. "But the chinampas
are endangered, and we want everyone to know we've got to do more to save
them," he adds. "Even our schoolbooks forget there are still chinamperos
alivetoday. We're not history yet."

The person most responsible for alerting the outside world to the chinampas
asan ecologically-sound farming model is a conservation-minded botanist named
Arturo Gomez-Pompa. Gomez-Pompa first became involved almost twenty years ago
through his work with the National Research Institute of Biotic Resources, or
INIREB, based in Veracruz. As Gomez-Pompa saw it, the challenge was to modify
and then transfer the chinampa system, long adapted to the climate and soils
of Mexico's temperate highlands, to marginal sites in his country's tropical
lowlands in order to increase food production while preserving the
environment. This idea's feasibility was underscored by archeological
evidencefrom Belize's Pulltrouser Swamp and the Yucatan's Candelaria Basin
showing
that the Mayans also had once farmed raised fields (camellones).

Chinamperos were brought to Veracruz and nearby Tabasco to assist in the
construction of test plots in coastal swamps and lagoons. Modifications were
made along the way, sometimes after painful trial and error, and some
experiments were eventually abandoned. But others gradually took hold and
attracted wide outside interest. The most successful of these are the raised
fields of the Chontal Indians, located not far from Tabasco's capital.
Today'sthriving Chontal plots apply a modified chinampa technology to the
Mayan
forest garden system known as "pet kot", a small mixed-use area of fruit
treesand food crops. Aquatic plants are composted as fertilizer, but there is
little attention to the other standard chinampero practices of preparing and
maintaining soil. Thus, even though Gomez-Pompa sees that chinampa building
and farming techniques cannot be transferred wholesale from one place to
another, he feels they do provide a model for reclaiming and using marginal
areas in otherwise land-scarce regions.

But while chinampa-based agriculture might be ecologically and economically
feasible elsewhere, questions remain about the future of the original plots.
Are Xochimilco's chinampas simply a monument to Mexico's past, or are they
still agriculturally appropriate for their time and place in a city of twenty
million people? Given the nation's total food needs, some experts consider
them as anachronistic as the tiny patches of corn still planted downtown. On
the other hand, one recent estimate suggested they could potentially satisfy
one quarter of Mexico City's demand for fresh vegetables.

With or without major public subsidy, and regardless of the alternative use
ofthe land they still occupy, Xochimilco continues to serve as a living
textbook
of pre-Columbian agricultural science. And, with the help of dedicated
chinamperos like Jose Genovevo and experts like Arturo Gomex-Pompa, we are
finally learning to see the value of this ancient farmlore. Whenever today's
chinamperos abandon their plots, this wisdom is irrevokably erased. Thus, if
we mourn the loss of individual species of plants as the rainforest is cut,
wemust also mourn the loss of this collective knowledge of planting as the
chinampas are drained.

Louis Werner is a freelance writer and independent producer/director of
documentary films.

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