Following the collapse of the Soviet Union four years ago, Cuba's supply of fertilizers and pesticides was cut back 80 percent, its fuel supply cut in half. Now, there is an urgent need for the country to feed its people . . . but there is no money to buy farm chemicals or oil. So Cubans have turned to organic farming on a national scale. It's a high risk gamble that uses plows and oxen instead of tractors and turbines . . . and biological pest controls instead of chemical pesticides. Reporter Bruce Gellerman traveled to Cuba to find out what farmers have learned . . . and what lessons the experiment holds for sustainable growers around the world.