Owing to the great dependence upon weather, an element considered to be beyond human control, substantial religious beliefs, rites, and prayer evolved around the growing of crops, and in particular the growing of the four principal corn types of the region, characterized by their colors: red, yellow, blue, and white. The presence of corn as a spiritual symbol can often be seen in the hands of the "Yeh" spirit figures represented in Navajo rugs, in the rituals associated with the "Corn Maiden" and other kachinas of the Hopi, and in various fetish objects of tribes of the region.
American Indians in the Sonoran Desert and elsewhere relied both on irrigation and "Ak-Chin" farming—a type of farming that depended on "washes" (the seasonal flood plains by winter snows and summer rains). The Ak-Chin people employed this natural form of irrigation by planting downslope from a wash, allowing floodwaters to slide over their crops.