From NPR:

On U.S. farms, gleaning is making a comeback, as a national anti-hunger organization has turned to the ancient practice to help feed the poor. And it also gives farmers a way to use produce that would otherwise be wasted.

In the Old Testament, farmers are told not to pick their fields and vineyards clean, but instead to leave the edges for orphans, widows and travelers. In the modern day, gleaning is more about preventing would-be waste.

"The statistics are that 96 billion pounds of food are left — this is pre-consumer food — goes to waste in this country," says Linda Tozer of the Society of St. Andrew, an organization that coordinates farmers around the Southeast and out West.

Gleaning A Harvest For The Needy By Fighting Waste