Corn farmer Jerry McCulley sprays the weedkiller glyphosate across his cornfield in Auburn, Ill., in 2010. An increasing number of weeds have now evolved resistance to the chemical. Seth Perlman/AP hide caption

itoggle caption Seth Perlman/AP

Pine nuts aren't farmed; they're harvested from forests. The nuts are hidden inside the cones of certain species of pine, such as this pinyon in Utah's Fishlake National Forest. Scott Smith/Corbis hide caption

itoggle caption Scott Smith/Corbis

Soybeans in a field in Springfield, Neb., on Wednesday. The nation's corn and soybean farmers will bring in by far the largest harvest ever this year, driving down the price of the commodities, according to the U.S. Department of Agriculture. Nati Harnik/AP hide caption

itoggle caption Nati Harnik/AP

Chicks in the Perdue hatchery in Salisbury, Md. The company says an increasing number of its chickens are now raised using "no antibiotics, ever." Dan Charles/NPR hide caption

itoggle caption Dan Charles/NPR

Bob O'Connor, a Foster Farms veterinarian, holds an 11-day-old chick at a ranch near the town of Merced, in California's Central Valley. Dan Charles/NPR hide caption

itoggle caption Dan Charles/NPR

Tractors sit on a sugarcane plantation on the land of a Guarani-Kaiowá indigenous community in Brazil, where Oxfam has alleged "land grabs" unfairly take land from the poor. The United Nations is drafting voluntary guidelines for "responsible investment in agriculture and food systems" in response to such concerns. Tatiana Cardeal/Courtesy of Oxfam hide caption

itoggle caption Tatiana Cardeal/Courtesy of Oxfam