When the dust storms of the 1930s threatened to destroy U.S. farming and agriculture, Hugh Bennett knew what to do. For decades, he had studied the soils in every state, creating maps showing soil composition nationwide. He knew what should be grown in each area, and how to manage the land to conserve the soil. He knew what to do for weathering and erosion. To do that, he needed the government's help. But how do you convince...