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.
Indigenous peoples in Ecuador
Using the system of multicyclic agriculture, which allowed them to have year-long harvests of a wide variety of crops by planting at a variety of altitudes and at different times, the Sierra people flourished. Generally, an ethnic group farmed the mountainside nearest to it. Cities began to specialize in the production of goods, agricultural and otherwise. For this reason, the dry valleys, where cotton, coca, "ají" (chili peppers), indigo, and fruits could be grown and where salt could be produced, gained economic importance. Sometimes, tribes farmed lands outside their immediate purview. These goods were then traded in a two-tiered market system.