Agriculture in the prehistoric Southwest
After the Hohokam disappeared, Spanish explorers of the 16th century noted the use of canal irrigation in only two areas of the Southwest: eastern Sonora, primarily practiced by the Opata and Lower Pima, and among the Pueblos of northern New Mexico. Irrigation by the Opata and Pueblos had different objectives. In Sonora, with a long growing season, two crops of maize a year were grown in river valleys. The spring crop during the dry season was dependent upon irrigation; the summer and fall crop during the rainy season utilized irrigation to supplement rainfall. The necessity of irrigation probably required a high level of social organization. In New Mexico, with only one crop of maize per year possible, irrigation was supplemental and the lesser dependence on irrigation implies less social organization than in Sonora.
Pueblo III Period
During the Pueblo III Period most people lived in communities with large multi-storied dwellings. Some moved into community centers at pueblos canyon heads, such as Sand Canyon and Goodman Point pueblos in the Montezuma Valley; Others moved into cliff dwellings on canyon shelves such as Mesa Verde or Keet Seel in the Navajo National Monument. Typical villages had included kivas, towers, and dwellings made with triple coursed (three rows of stones) stone masonry walls. T-shaped windows and doors emerged for both surface and cliff dwellings.Three major regional centers with cliff dwellings and community centers were Chaco Canyon National Historical Park in New Mexico, Mesa Verde National Park in southwestern Colorado and Betatakin and Keet Seel area (Navajo National Monument) in Arizona.As a means to improve agricultural yield, the Pueblo III period saw advancements in water conservation. Stones were placed in and around farm land to divert flow for irrigation, water conservation and to reduce run-off. This was accomplished through the use of bordered gardens, reservoirs, check dams and terraced gardening plots – building upon the techniques of the Pueblo II Period. Corn, beans and squash were cultivated using dryland farming techniques. Their diet was supplemented with wild plants, such as beeweed. As nutrients were depleted from over-farming, new land was found and cleared for cultivation.