The Dirt on Soil

Go to any big farm show and you’ll likely see the gleaming harvesters and gargantuan combines that have made high yield farming possible. But those same machines are mashing soil into impenetrable slabs. The process is called compaction, and one expert suggets that the reduced harvests from soil compaction cost Midwestern farmers $100 million in lost revenue every year.

Concern over soil is a worldwide problem. We keep hearing about "Our Good Earth," a National Geographic cover story that's getting a lot of attention. In it, science writer Charles Mann looks at problems and solutions in several of the world’s hardest hit reagions. So we invited him to tell us more.

Take an interactive quiz to test your knowledge about soil.

(Photo by Andrew Stawarz)