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.
Anasazi Heritage Center
While other native peoples were hunters and gatherers, pueblo people resided in permanent communities called pueblos and grew their own crops. The Ancient Pueblo people may have lived in the Four Corners area as early as 1500 BC. As many as 20,000 people may have lived and farmed in the Montezuma County, Colorado area. Each person required about one acre of land for up to 40 harvested bushels of corn per year. Other sources of food were obtained through gathering wild plants, like berries and piñon nuts, growth of beans and squash and hunting. The area was affected by periods of drought, including one in the late 13th century. That and other factors resulted in the permanent move by 1300 AD of area pueblo people south to present-day New Mexico and Arizona. "Anasazi", a term commonly attributed to ancient pueblo people, has been used since its publication in the 1930s. The Navajo word does not represent specific tribes but means enemy or outsider. The term is disliked by the modern Pueblo people who hold their ancient ancestors sacred and celebrated through spiritual rituals and journeys.