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 II Period
The optimal southwestern farming locations were adjacent to springs, seeps or marshes. Early in the Pueblo II period, the most desirable spots had been taken and, presumably young, families searched out open land to farm, hoping that precipitation would be sufficient to support their crops. There were periods of time of seasonal hunger and drought when people moved away from their villages and returned "following the rains," stories told by elders of pueblo communities. Evidence of near starvation as children are evident in the interrupted growth lines in their bones and "enamel hypoplasias" in their teeth.