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 Pueblo II Period (AD 900 to AD 1150) was the second pueblo period of the Ancestral Puebloans of the Four Corners region of the American southwest. During this period people lived in dwellings made of stone and mortar, enjoyed communal activities in kivas, built towers and water conversing dams, and implemented milling bins for processing maize. Communities with low-yield farms traded pottery with other settlements for maize.