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.
Agriculture in Spain
Crop areas were farmed in two main manners. Areas relying on non-irrigated cultivation ("secano"), which made up 85 percent of the entire crop area, depended solely on rainfall as a source of water. They included the humid regions of the north and the northwest, as well as vast arid zones that had not been irrigated. The much more productive regions devoted to irrigated cultivation ("regadio") accounted for 3 million hectares in 1986, and the government hoped that this area would eventually double, as it already had doubled since 1950. Particularly noteworthy was the development in Almeria — one of the most arid and desolate provinces of Spain — of winter crops of various fruits and vegetables for export to Europe.