Agriculture

In the prehistoric Southwest, the Hohokam were unsurpassed as farmers. With their elaborate system of irrigation canals, they were able to cultivate a large variety of domesticated plants. These crops included corn, jackbeans, tepary beans, lima beans, squash, barley, amaranth, gourds, cotton and tobacco. In addition, the Hohokam planted or encouraged the growth of wild desert plants, such as agave (century plant) and cholla cactus, in the drier or marginal areas of their fields.

Although archaeologists do not know how the Hohokam divided their labor among the sexes, ethnographic data indicates that for most Southwestern groups, men and women performed different tasks related to subsistence. Men typically hunted game, cleared the land and prepared the soil for gardens. Women planted and harvested the crops and prepared all the food.

Ethnographic data of the historic Pima indicate that agricultural fields were divided into small plots and farmed by extended family groups. Although it cannot be determined through archaeological investigation, the Hohokam, like historic American Indian groups, most likely planted a wide variety of plant species together in their fields. In addition, the Hohokam may have double-cropped, producing two yields per year by taking advantage of two growing seasons.

The Hohokam planted their fields between rows of lateral irrigation canals, as well as along washes and in areas which received adequate runoff from rainwater. Their fields covered thousands of acres in the Salt River Valley alone and produced enough food for tens of thousands of people. Animals attracted to the lush Hohokam fields were actively hunted and likely constituted a major portion of meat in the Hohokam diet. At Pueblo Grande the majority of the agricultural fields were located to the west of the village, among the canals that originated to the south in the Park of Four Waters.

Canals/Irrigation

To farm the desert successfully, the Hohokam tapped the rivers of the Sonoran Desert by constructing irrigation canals. Using simple tools, the Hohokam created the largest prehistoric irrigation system in North America. Many modern canals in the Phoenix metropolitan area are located in the same place as the prehistoric Hohokam canals. Some of the last undisturbed prehistoric Hohokam canals are located at Pueblo Grande in the Park of Four Waters.

The Hohokam experimented with small irrigation ditches early in their occupation of the Salt and Gila river valleys. By A.D. 600, they had developed lengthy networks of canal systems. Eventually, hundreds, perhaps thousands, of miles of these waterways wound out from the Salt and Gila rivers, creating swaths of green vegetation surrounded by sprawling villages. Many of these irrigation canals were over seven miles (11 km) in length. The longest recorded Hohokam canal extended possibly as much as 20 miles (32 km) or more, beginning at Pueblo Grande, and reaching as far west as present day Glendale.

The Hohokam canal system consisted of several integrated parts. To direct water from the river into their canals, archaeologists assume the Hohokam constructed weirs at a 45 degree angle to the flow of water. A weir was a type of log and brush dam that extended into the river but not completely across. In this way the weir raised the water level of the river and forced it into the main canal. To control and regulate the flow of water inside the main canal, a headgate was constructed, also of logs and brush. The main canals carried water away from the river and toward villages. Branching off from the main canals were distribution canals, which transported water to the fields. Finally, smaller lateral canals released the water directly onto the fields.

Canal construction was not an easy task for the Hohokam. Having no draft animals, the Hohokam had to dig by hand through the hard, sunbaked soil using large wedge-shaped stone hoes, stone axes and digging sticks. The excavated dirt probably was then removed in baskets and used to build embankments along the sides of the canals. Some canals were very large, reaching widths of over 50 feet (15 m). Main canals at Pueblo Grande (Canal System Two) are as much as 30 feet (9 m) wide and 10 feet (3 m) deep, with banks up to 10 feet (3 m) high, making the canals 20 feet (6 m) deep from top to bottom.

Besides the actual digging of the canal, the Hohokam also had to determine the most opportune location for the canal. This required a knowledge of hydraulics. Due to the complexity of the canal system, the Hohokam would have had to lay out the course of the canal from start to finish before construction could begin. In locating and building their canals, the Hohokam may have used simple surveying equipment to determine elevations and gradients over long distances.

Hohokam canals were engineered in such a way that they were wide at the headwaters and gradually narrowed as they reached their terminus or end. In thisway, water levels were kept constant and there was an even flow of water from beginning to end. Canal gradient or slope was crucial for the proper working function of the canals. If the grade was too steep, the water would run too fast and erode the canal banks. On the other hand, if the grade was too gentle, the water would run slow, dropping its sediment load and causing the canal to silt up. Either one of these malfunctions would have required countless hours of labor to remedy.

Most Hohokam canals were constructed with different gradients, depending on the canal's location within the system and its distance from the river. Canal gradients within Canal System Two, for example, varied from 4.8 feet (1.5 m) per mile (1.6 km), to 1.2 feet (0.4 m) per mile (1.6 km).

The topography of the land surrounding Pueblo Grande made it an ideal location for the headgates of irrigation canals. The site is located just west of Tempe Butte, where the bedrock is close to the surface. The river bends to the south at Pueblo Grande, making it a favorable location for irrigation canals heading in a northwesterly direction. In addition, the contour of the land in this area is relatively flat and uniform, allowing for several canals to diverge from the river for considerable distances. During the Classic period (A.D. 1150-1450), as many as ten canals were in use at the same time at Pueblo Grande, but many of those canals carried water to fields at other villages.

The Hohokam canal system was built over several centuries, and not all Hohokam canals identified by archaeologists were in use at any one time. Over a period of more than a thousand years canals were built and abandoned as water flow changed, headgates were destroyed by floods, or canals were filled by sediment deposition. According to archaeologist Jerry Howard, the greatest amount of canal construction in Canal System Two occurred early in the Hohokam chronological sequence during the Colonial period (A.D. 750-900). During this period, canals damaged by floods were regularly rebuilt. By the beginning of the Sedentary period (A.D. 900-1150), canals closest to the Salt River were abandoned and new re-placement canals were constructed on higher ground. During the Sedentary and Classic periods, the Hohokam consecutively built canals further and higher from the river while discontinuing use of some of the older southern canals. Abandonment of canals also led to the abandonment and shifting of villages from the south (near the river) to the north (away from the river). An exception to this trend was the construction during the Classic period of a new, independent canal system and village at Pueblo Salado, just north of the Salt River where the Sky Harbor Airport is now located. This probably was a reclamation effort to farmland previously abandoned during the earlier Colonial period.

The Hohokam canal system and all of its elaborate parts indicate that the Hohokam had a somewhat complex sociopolitical structure. Beyond the canals themselves, this complexity is expressed during the Classic period in the location of villages containing earthen platform mounds approximately every three miles (5 km) along the irrigation canals. This suggests that the theocratic or secular elite of these platform mound villages controlled the construction of the canals plus the flow of water in them, their maintenance, and water allocation.

At Pueblo Grande, it is estimated that the canal system originating on the southern edge of the site irrigated at least 10,000 acres (4,047 hectares) of farmland. Pueblo Grande is situated at the headwaters of this canal system that controlled the water for the majority of the Hohokam villages on the north side of the Salt River. Because of its strategic location, Pueblo Grande would have been very important to other villages using the canals along the same canal system. This may be the reason why the platform mound at Pueblo Grande, containing as much as 50,000 cubic feet of earth and stone, is the largest of all the platform mounds located along Canal System Two.

Hunting and Gathering

The Hohokam harvested a long list of wild foods. Bean pods were obtained from mesquite trees (and also from other desert trees). Desert shrubs provided seeds and fruit. Buds and fruit from cacti such as the saguaro, cholla and prickly pear were eaten. Acorns were gathered in the mountainous areas, hearts of agave plants were roasted, and various roots, bulbs, and herbs were collected to add to their diet. The Hohokam took advantage of the fact that there are more than 200 species of edible wild plants in the Sonoran Desert. In some areas, the Hohokam may have set fire to tracts of land to promote the growth of certain grasses and cool season herbs they favored.

The Hohokam had only one domesticated animal, the dog, and there is no evidence they ate them. However, they did eat a wide range of wild desert animals. To accomplish this, the Hohokam probably employed a number of hunting techniques and devices. One of these, the bow and arrow, was adopted by cultures of the Southwest as early as A.D. 500. Although no actual bows have been recovered from Hohokam sites, it is known that the bow and arrow were used based on figures painted on pottery, images pecked in stone as petroglyphs, and from the recovery of stone projectile points or arrowheads. Another hunting device, known as the atlatl or spear-thrower, was used by earlier cultures of the Southwest and may have been used by the Hohokam as well. The Hohokam also are believed to have used traps, snares and nets to obtain fresh meat.

Based on archaeological evidence from trash deposits at Pueblo Grande and other Hohokam sites, the list of animals the Hohokam ate includes various species of rodents, birds, jackrabbits, cottontail rabbits, mule deer, white-tailed deer, pronghorn antelope, and bighorn sheep. Other food sources consisted of desert tortoise, mud turtles, and several species of waterfowl. Rabbits appear to have been the main source of animal protein for the Hohokam and would have been readily available not far from their villages, as well as in or near their fields.

Ethnographic data show that for most Southwestern groups small game was hunted by men, women, and children, often while gathering wild plants or tending fields. Large game, however, was hunted by small parties of men and involved certain rituals before and after the hunt. The Hohokam may have followed similar hunting procedures.

Domesticated dogs are often found buried at Hohokam villages, and canines may have served as pets and were used for hunting. More than a dozen dog burials have been excavated from Pueblo Grande, and the presence of bones of young dogs suggests that the Hohokam may have raised dogs at the site.

Fishing

Archaeological evidence indicates that the Hohokam fished the major rivers and streams of the Sonoran Desert. Many of the larger rivers ran year round and would have provided abundant fish as a source of protein. Hohokam canals also would have contained fish that could have been caught using fishing nets and traps. Species of fish found at Pueblo Grande and other Hohokam sites include minnows, chubs, Colorado River squawfish, and suckers. Gila Mountain razorback suckers can achieve weights of up to 30 pounds (13.6 kg) and would have provided the Hohokam a hearty meal.

Also living in the rivers and canals was a large molluscan community, including California floater clams, fingernail clams, and assorted snails. The presence of these clams and snails at Hohokam sites suggests they were an important supplemental protein source.

It is not clear, however, how important fish were to the Hohokam diet. Most excavations have not used screens with small enough mesh to recover fish bones. Although by using fine screens, archaeologists have recovered thousands of fish bones from trash deposits at Pueblo Grande which dated to the Classic period (ca. A.D. 1150-1450). It is possible that the Hohokam had increased their exploitation of riverine resources due to an inadequate amount of protein in their diet during that time period.

Conclusions

At first appearance, the Sonoran Desert looks like a harsh and forbidding environment. However, it is much more luxuriant and diversified than recognized by many modern people. The Hohokam developed several very successful strategies for living in this environment and, therefore, were able to achieve many cultural accomplishments. Some of those achievements are described in the following pages of this book.

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