Sweet potato evangelist Maria Isabel Andrade from the International Potato Center drives around Mozambique in her orange Toyota Land Cruiser. Dan Charles/NPR hide caption

itoggle caption Dan Charles/NPR

Potatoes come in all colors, like these Red Erik, Snowball, Cariboo, Purple Peruvian, Caribe and French Red varieties. David Cavagnaro/Corbis hide caption

itoggle caption David Cavagnaro/Corbis

These piglets on the Hardin farm in Danville, Ind., are going to cost more to feed than they will fetch at market. Dan Charles/NPR hide caption

itoggle caption Dan Charles/NPR

A tomato expert recommends planting seedlings in rich soil with lots of organic matter and a steady slow-release fertilizer. iStockphoto.com hide caption

itoggle caption iStockphoto.com

A clampdown on contamination in growing fields has pushed out wildlife and destroyed habitats. Adam Cole/NPR hide caption

itoggle caption Adam Cole/NPR

A dairy farmer drives some of his Holstein cows out to pasture in the Madison County, N.Y. town of Lenox. Jim Commentucci/The Post-Standard /Landov hide caption

itoggle caption Jim Commentucci/The Post-Standard /Landov

A member of the community supported agriculture program at Congregation Shearith Israel picks from boxes of squash and cucumbers in Atlanta. Some purists say CSAs are drifting away from their roots. John Amis/AP hide caption

itoggle caption John Amis/AP