Feeding the World in 2050

"Today's crops crisscross the globe: Mexico's tomatoes end up on your plate, our wheat heads to Africa. As a result, the challenge of growing twice as much food by 2050 to feed nine billion people-with less and less land-is everyone's problem. But scientists are hard at work fomenting a second green revolution. Here's how nitrogen-spewing microbes, underground soil sensors and fruit-picking robots will help keep food on our tables."