Forty to fifty-foot long taproots?
Here, the water's pretty close to the surface.
In fact, it's usually so close to the surface it severely undermines roads.
Nebraska was called the "Great American Desert" in the early 1800s by a primitive exploring the area, and like a modern-day primitive, he had the attitude, "If I don't see it, it doesn't exist."
So as a consequence, the Sandhills of Nebraska were one of the last places settled, in the continental United States. Eastern Nebraska was settled during the late 1850s (but only very thinly; Nebraska had less than 10,000 people when it became a state in 1867), the Platte River area all during the 1870s, and dutch508's territory, out in western Nebraska, about the early 1870s.
The vast interior of the state remained unpeopled until about 1900, when nonprimitives found that there was unlimited water under the Sandhills, just a few digs with a spade. The Sandhills of Nebraska is the Saudi Arabia of subterranean water, the largest underground reservoir of fresh water in the world.
The oldest building in the Sandhills town (population 3,000) where I lived when I was 10 years old, was a two-story structure marked "MDMXI"--1911. To me, that seemed about as old as the Pyramids of Egypt or Stonehenge or the Acropolis.....or at the very least, as old as the Tower of London.