What we call today the Great Plains (specifically, the High Plains) was the Great American Desert 150 years ago. (The term comes from the fact that desert basically meant treeless back then, which the High Plains most certainly were). The land was basically unsettlable until the introduction of better plows, deep wells for irrigation, and the railroads to allow for efficient import/export. And the happy coincidence that the late 1800s were an unusually wet period that gave rise to the disastrous moniker, "rain follows the plow."