A version of this article appeared in Preservation magazine in July/August 2003.
This practice, called land-extensive agriculture, provides protection against environmental challenges (such as long-term drought or localized storms) and human demands (such as population growth, either gradual or sudden, as when Cochiti Pueblo took in refugees during the 1680 Pueblo Revolt against the Spanish).
“When the Spanish got here in the 1500s, they described this land as a Garden of Eden. Now it’s dry,” Hena said defiantly as we jolted down the arroyo. “What’s different? We Indian people are not out there, managing the land. Nowadays, there’s a lot of erosion, and a lot of topsoil is lost. You can see it in the turbidity of the water when we have sudden rains and flooding.
|Is or isn’t it an ancient shovel?|
Archaeologist Kurt Anschuetz navigated his pickup slowly along the uneven bottom of the arroyo. Skirting hillocks and boulders, we made our way from Tesuque Pueblo into the high desert north of Santa Fe. From the front passenger seat, Louie Hena, a Tesuque farmer and tribal council member, shown near left with Anschuetz, scanned the sandy 60-foot walls. He was looking for the spot where he had seen what seemed to be the remains of small, gravel-mulched, cobble-edged fields (usually called grid gardens or gridded plots) built by his ancestors. The newly rediscovered type of early Pueblo agriculture is redefining the concept of irrigation and providing powerful new legal evidence for communities, like Tesuque, that are engaged in water litigation.
However, on that day in August 2001, Hena was concerned about PNM, New Mexico’s utility company. It had long been developing plans to march a power line through the area, which was part of Tesuque’s reservation. The utility’s archaeological studies—undertaken in 1985 as required under federal law—had found no evidence of the old plots that Hena had recently spotted.
But Hena knew that most archaeologists, accustomed to studying dwellings, wouldn’t recognize the little-understood fields. He hoped that Anschuetz, an expert on them, would agree that artifacts of Tesuque’s heritage were in harm’s way.
Hena had met Anschuetz, who directs the Rio Grande Foundation for Communities and Cultural Landscapes, a Santa Fe nonprofit that helps groups preserve their traditional lifeways, at a 1994 environmental conference at Taos Pueblo. The two men discovered a mutual fascination with the early agriculture of northern New Mexico and undertook a cross-cultural collaboration. Combining the analytical tools of the scholar with the practical knowledge of the Indian farmer, they have co-published papers and given presentations to groups including Native communities, gardening students, and lawyers.
BUILDING THE GARDENS
As the ancestors of today’s Pueblo people moved south from the Four Corners area (the point where what are now Colorado, Utah, New Mexico, and Arizona meet) after 1250, they expanded on the agricultural techniques that they’d used up north—mainly contour terraces, reservoirs, ditches and check dams. In the process, they created a dynamic system of multiple technologies that they scattered across the land.
|Hena tries what seems to be an old planting tool|
Gravel-mulched, rock-bordered fields were one of the new techniques the ancestral Puebloans devised upon arriving in what is now north-central New Mexico. They eventually constructed about 10,000 acres’ worth of the rectilinear plots in the valleys of the Rio Grande and its tributaries; most of the fields were installed between 1300 and 1500. Each grid garden is, on average, about nine feet by twelve feet, and is bordered by cobbles that are approximately seven inches high and ten inches long, laid end-to-end.
The farmers covered the topsoil within each rectangle with gravel mulch, which was designed to trap rainfall, melt snow, and prevent evaporation. The mulch also encouraged moisture to soak into the ground, where it seeped downslope past the roots of crops in one hillside field after another. By doing this, they made sure that little evaporated or ran off, as rain or snowmelt ordinarily would—essential in this region of meagre precipitation.
In the rich soil, the farmers grew cotton for clothes, as well as corn, beans, squash, perennial herbs, and other foodstuffs. They bred special domesticated plants, such as corn with an especially long mesocotyl (the first shoot that breaks through to the surface after germination); this variety can be planted at depths of up to 16 inches to take advantage of underground moisture.
In and around the beds, the early Puebloans managed other, non-domesticated plants (contemporary Indian farmers don’t like to call them “wild,” since they were encouraged to grow, not merely collected randomly). This huge array of affiliated plants—including purslane, lamb’s quarters, amaranth, yucca, and much more—provided everything from food and medicine to fiber and soap. Prickly pear cactus, which seeds itself in cracks in rocks, sprang up between the cobbles, providing edible pads and flowers as well as a spiky fence that kept out small predators. Remnants of these plant populations can still be seen in some plots.
Clusters of grid gardens range in size from a few isolated plots to hundreds of contiguous ones. In aerial photographs of the region, the groupings look like nets cast over the hilly land bordering the rivers. They have caught the eye of pilots as far back as Charles Lindbergh, who photographed them while flying over Abiquiu Mesa in 1920s. Their ground-hugging patterns can be easier to see from the air, I learned in a conversation with pilot Lee Baker, whose husband, archaeologist Tom Baker, photographs old sites from her plane. “In some areas,” she said, “where they are very subtle, you can see them while you’re flying. Then, if you parachuted right down into them, you probably wouldn’t be able to see them at all.”
Initially, I couldn’t pick out the gridded plots at all when Clayton Brascoupé showed me the ones at Poshu-ouinge, a 13th-to-18th-century pueblo in the Santa Fe National Forest. Brascoupé is the Mohawk-Algonquin director of the Traditional Native American Farmers Association, an intertribal community-outreach organization in Santa Fe. It was my first visit to the Southwest and, frankly, the area looked to me like an undifferentiated expanse of rocks, sand, and the occasional shrubby tree.
Then, as Brascoupé pointed example after example, the subtle rectangular outlines snapped into focus. I was to learn that day, and in subsequent visits to other plots, that so much of what made them work so well was just at, or even below, the surface. Their efficacy has profound implications for modern land use; they are also redefining the concept of irrigation, which affords powerful support for present-day Pueblo water claims.
The grid gardens were ignored or misunderstood by scholars for much of the 20th century. In 1880, guides from Santa Clara Pueblo identified the structures as agricultural when they led Swiss-American explorer and archaeologist Adolph Bandelier to one of their ancestral pueblos. Later researchers rejected this description as oral history, therefore unreliable, and devised alternate explanations that seem fanciful in retrospect. They postulated that the rock enclosures were plans for homes that were never built or the remains of pre-ceramic pueblos. Why anyone would have planned such immense dwellings, or how they could have constructed them, remained as much a mystery as what they were to begin with.
During the late 1970s, David Bugé, Katherine Fiero, Richard Lang, and other prominent archaeologists took a second look at hypotheses about the rock traceries and reintroduced the idea that they had an agricultural purpose. Over the next two decades, important studies and doctoral dissertations by Anschuetz, Timothy Maxwell, James Moore, John Ware, Steven Dominguez, and others confirmed this.
PROTECTING THE SITES
Roads, buildings, and other facilities have obliterated some of the grid gardens; I saw cattle lumbering through others. All-terrain vehicles also cause tremendous havoc; ATVs not only rip up the ecologically fragile desert surface, they also enable their owners to bounce through hitherto inaccessible places. “Distance from roads has always been the best protection for old sites,” says archaeologist and hydrologist Dominguez. “Now, with increased access, so much is in danger.”
The remaining fields sit on land with an unrelated patchwork of ownership: individuals, municipalities, Indian reservations, the State of New Mexico, the U.S. National Forest Service, the Bureau of Land Management, and the Archaeological Conservancy, among others. Some of these entities are determined to protect the gardens and their associated dwellings and field houses through legislation forbidding vandalism and theft, or via locked gates. Others may not know the structures exist.“They are protected under preservation law, but it’s such a vast landscape, and the gardens cover thousands of acres of it. That’s the tough part,” says J. Michael Bremer, Forest Archaeologist of the Santa Fe National Forest. “Even at our fenced site at Poshu-ouinge, cows and elk sometimes break in.”
HOW THEY WORK
As we lurched along the arroyo, Hena and Anschuetz filled in some details. “My ancestors treated the land as a sponge, encouraging water to soak into the ground,” Hena explained. In contrast, he said, the modern irrigation systems you may be more familiar with flush water over the earth’s surface in concrete-lined canals. “It looks efficient, but a lot is lost to evaporation that ends up as rain somewhere else,” said Anschuetz.
Hena added, “You aren’t feeding the roots of beneficial plants or recharging wells along the way. In recent decades, the Bureau of Indian Affairs has done us, and other Pueblos, the supposed favor of lining our irrigation ditches with concrete. Here at Tesuque, the wild plum trees along the ditches died as a result, and we lost a food source.” Also important, water passing through a concrete-lined ditch doesn’t recharge the aquifers, a critical failing in the arid West, where the great underground water repositories are shrinking nowadays—a sword of Damocles hanging over all of us.
Under cultivation until the mid-1700s, many of the now-unused grid gardens are still doing what they were designed to do—hold moisture and soil and promote growth—even though no farmer has turned up to maintain them in 250 years. “Often, you can spot them because they’ve got grass growing in them,” Anschuetz pointed out.
For all their subtlety, they’re remarkably rugged. During the early 20th century, a dirt road was built through the plots near Sapawe, a 2,000-room pueblo on the banks of the Rito Colorado that was occupied during the 1500s and 1600s. After all these years, and periodic passes by road scrapers, the cobbles haven’t budged.
By siting this particular type of field on hills and mesa tops, the farmers of old avoided the cold air that settled in the flood plains of major rivers and shortened the growing season in the valleys. On the other hand, higher-altitude plantings couldn’t be irrigated with water diverted from the streams, as those in valleys could have been; manipulating precipitation was therefore critical to the grid gardens’ success.
Deciding where to site their plots was not the farmers’ only consideration. They also tailored stone hoes, shovels, axes, and digging sticks to fit the requirements of different crops and soil types. The heavy tool heads can still be found in the beds; their owners likely stashed the items where they needed them and carried handles that could be lashed on. At the end of the growing season, they left a cover of stubble behind to shelter birds and small animals and to entice browsing deer, which contributed to the community’s meat supply.
|Demonstration garden at Pojoaque Pueblo|
“In the old days, with our ancestors managing the watersheds from the top down, the water soaked into the ground, slowed down, and continued downhill and out onto the plains without taking the topsoil with it. In fact, the stuctures we Pueblo people placed on the hillsides captured topsoil, increasing it.”
RUNNING THE NUMBERS
For their sophistication, as well as their extent, the grid gardens are as significant as the aqueducts and other engineering feats of Rome, according to Dominguez. But, whereas the aqueducts are impossible to miss, these fieldworks are nuanced modifications of the landscape that are nearly hidden in plain sight.
To bolster his claim, Dominguez subjected the plots to rigorous hydrological analyses. Digging into the gardens with a mason’s trowel; then, using sieves with graduated mesh sizes to separate rock from soil, he gathered data from a promontory called La Mesita, in the Rio Santa Cruz Valley, northeast of Santa Fe. Upon analyzing the numbers, he discovered that the fields operated with diamond-cutter accuracy. The farmers used optimum stone sizes for their gravel mulch, which increases water absorption, cuts evaporation and runoff, and checks erosion. “Fifty millimeters is the upper limit for the size of stones that can be used effectively,” Dominguez explained; in the fields he studied, most stones were between two and fifty millimeters. Further, he noted, the entire layer should be at least three centimeters thick. At La Mesita, the rock coverings of north-facing plots averaged just that; in south-facing beds, where plants had to survive additional hours of dessicating sunlight, the thickness was plumped up to an average of five centimeters.
Snowmelt was as important as rain in a region that counts the winter months among the wetter ones. “I was out in the middle of a snowstorm when I realized how effectively the gravel mulch melts snow, building up moisture for spring planting,” he recounted. “The rocks hold heat, so the garden beds were patches of bare gravel, while the snow was piling up around them.”
The cobble borders also helped collect winter precipitation. As a rule, Dominguez says, hydrologists find that the most efficient snow fences—including low ones like these—have gaps no larger than 25 centimeters, with all the openings adding up to 40 to 60 percent of the surface area. Measuring the barriers at La Mesita, he calculated that they conformed to these exact requirements.
Then Dominguez checked topographical maps to see where the structures were placed on the landscape. Again, the farmers were spot on: The fences were at ideal angles to the prevailing winds and at optimum spots on the hillside slopes to gather snow.
And, the gardens’ builders had accurately calibrated the proportion of fence height to distance between barriers; the snow would have just filled one plot with a drift before hitting the next row of stones and forming another billow. The dimensions of the beds deviated from the nine-by-twelve-foot norm in spots where changes in a hill’s incline would have caused the wind speed to increase or decrease, thereby altering the lengths of the drifts. “This ability to take advantage of wind speed and direction is why you see a lot of grid gardens on hilltops--and why you see them from the air,” Dominguez says. “The only kind of moisture that moves upslope is blowing snow.”
The precision with which the fields were constructed, he added, gave the farmers tremendous flexibility, allowing them to deal with changes in terrain, to respond to short-term changes in weather, and to survive long-term environmental and population shifts.
To achieve this exactitude, the old-timers put their faith in observation itself, rather than in instruments of observation. The ability to look carefully has so atrophied for most modern people, they may have a hard time believing the ancients were so acute, says Dominguez: “We city dwellers have no clue. For me, the book learning was just part of being able to do this work. The other part was getting out there, seeing the rain falling or the snow blowing. The fields’ builders were walking the land, observing spring growth, looking at plants responding to different conditions, watching how everything interacted. And many generations of meticulous observers preceded them. The farmer of today—the farmer of agribusiness—is a technician. He follows instructions. The expertise resides not in him, but in John Deere or Monsanto.”
The ancestral farmers even figured out that you have to deliver air as well as water to the plants’ roots, says Anschuetz. In some locales, he and Hena found that the old Pueblo irrigation ditches spilled their water through openings that were partially blocked with rocks, creating turbulence and aerating the water so that it was rich with oxygen.
“The symbology of that facet of the planting is so incredible,” says Tessie Naranjo, a sociologist from Santa Clara Pueblo who has written on Pueblo agriculture and pottery. “We have a supernatural being called the water serpent. You see him in decorations on our pots. He is the aerator of the ground and makes it breathe so the crops can come up.”