However, the crop is highly fertilized, and is a significant source of nitrous oxide, a powerful greenhouse gas.
Much of the valley, to the east side of the river, was a semi-desert region covered with scrub, mesquites, and cacti.
It was not until the end of the 19th century that the irrigation project conceived by Carlos Conant was developed, and a vast area began to be used for agriculture.
After the Mexican Revolution, the federal government took control of Sonora's irrigation infrastructure and after World War II, began extensive dam and reservoir construction.
From the 1940s to the 1970s, advanced agricultural techniques were pioneered by Norman Borlaug of the International Maize and Wheat Improvement Center (CIMMYT) based in Ciudad Obregón.