On a warm November day in Yuma, Arizona, the desert sun is beating down on a sea of low, green fields. Here, near the banks of the Colorado River, Matt McGuire is surveying an expanse of vegetables that sprawls into the desert landscape.

“You find it on the grocery shelf and it’s a leafy green,” he said, “it probably came from here. Because about 80-85% of the vegetables in the wintertime come from this area.”