Nogales, Arizona is the largest inland food port in the world. Much of the fresh produce trucked up the "food superhighway" of Mexico's west coast comes through there — and a shocking amount of it doesn't travel much farther, dropping into local landfills instead of being sent to consumers.

It's a loss to the farmers who harvested the food and to the consumers who would have eaten it, argue film makers Jesse Ash and Phil Buccellato, who made an eight-minute documentary featuring Gary Paul Nabhan, a former MacArthur fellow and advocate for sustainable food reform. The film opens with footage of just-ripe tomatoes being bulldozed.

"If the Florida tomato prices drop on a certain day," Nabhan narrates, "120,000 pounds [of tomatoes] might be thrown into a landfill" in Nogales, while much smaller quantities might end up in food banks or in livestock feed.

Cut to Yolanda Soto, the CEO of Borderlands Food Bank: Borderlands "rescues" between 30 and 40 million pounds of produce each season and distributes it to rural residents, providing fresh fruits and vegetables at less cost than the nearest grocery stores. "Vegetables are expensive," says Soto, and the area has "a very high rate of diabetes."

Nabhan is perturbed that this is happening in southern Arizona, where high rates of food insecurity coexist with significant biodiversity: "If we can't use that biodiversity to make life better for the very people who live here, something is wrong," he says.

About a quarter of the produce Americans eat comes through US-Mexico border towns. Beyond changing wasteful practices in the produce-trade supply chain, Nabhan wants to see more people growing their own food.

Nabhan spearheads Native Seeds/SEARCH, a "grassroots movement to preserve the agricultural legacy of southern Arizona," which stores and distributes ancient crop seeds to local farmers and community gardens.