The Grass That Holds the Sandhills

First light in October comes up behind the hills east of Thedford and touches the ridges one at a time. Nebraska 2 runs west out of town, a black ribbon laid over country that rises and falls like deck swells. Frost lies heavy in the hollows until late morning; the crests dry first, going from silver to pale bronze within the hour. A windmill turns slowly in the lee of a dune, the pump rod rising and falling, the only moving thing for miles except the grass.

The grass is in motion all the time. The west wind arrives before breakfast and does not let up; it comes off the high plains with no range to stop it, and every blade on every slope bends the same way at once, so the whole country streams like water. But the hills themselves do not move. They have not moved for a long time, which is the remarkable thing about them: these are dunes.

An ocean standing still

The Sandhills cover about a quarter of Nebraska, from the Niobrara River south to the Platte, and across much of that distance there is not a level acre. Under the grass is sand — clean, pale, beach-colored sand — laid down as dunes by wind. In the cold, dry centuries at the end of the last ice age, the rivers here were braided, shifting things, spreading ground-up rock out of the mountains across the plains. When the water shrank, the wind took the dry beds apart and built hills. It did it again in later droughts, most recently about a thousand years ago, when the sand ran freely and open dunes moved over the country.

Then the grass came back. Not all at once, not everywhere evenly, but it came: first the pioneers that can live on bare sand, then the tall bunchgrasses that stitch a dune together. Nothing more dramatic had to happen. Wind still moves sand grain by grain, but where grass has rooted, the grains are no longer for sale. The result is the largest dune field in the Western Hemisphere, and the largest anywhere held still by grass.

The stakes are plain from the lip of a blowout. A blowout is a dune's scar — a raw bowl of open sand where the cover broke and the wind reached what lies beneath. It can begin with a dry year, an overgrazed slope, a single dead plant. The wind works the bare face, sand skims out like water, and the bowl deepens. Range country has learned to read these scars and to heal them by resting the pasture and letting the first plants in. Given time and rain, the grass closes the wound itself.

The crew of the dunes

The grasses that do this work are not the lawn kind. They are the tall prairie old-timers, and each one has a job.

• Sand bluestem is the big one, up to a man's shoulders, with a seed head shaped like a turkey's foot. Its roots go down a man's height and more; each plant is a small forest underground.
• Prairie sandreed stands stiff and upright, its roots running like cables through the top few feet of sand, lashing it in place.
• Little bluestem is shorter and fine-bladed; come October it turns the color of rust and old blood, and the hillsides carry it like a fire moving downwind.
• Needle-and-thread grows a seed with a long twisted tail that bores into the sand, planting the next generation without any help.
• Blowout grass is the pioneer, first to volunteer on bare sand. It sends out long rhizomes through the loose surface, catching grains and giving the slower grasses a hold.

This is the order of things. Blowout grass takes the open wound; needle-and-thread and sandreed bind the slope; bluestem moves in and makes prairie of it. The dunes are not static. Sand is caught at the rate the grass grows and released at the rate the grass fails. The whole arrangement depends on keeping cover, which is why the history of this country is the history of its grass.

A contract with grass

Bison once grazed these slopes, and cropping, dung and hoof arrived with them. Cattle run the same contract now. A cow takes grass, and her weight and step keep the sod from going stale; a lightly grazed pasture turns over like a field in rotation. The economy here is grass on the hoof. A ranch out here is measured in sections, and a section is a square mile, because one acre worked as the wind works it will not carry much.

Homesteaders learned this the hard way. A quarter section of sand could not raise a family; it would barely raise dust. In 1904 the Kinkaid Act offered 640 acres to anyone willing to try, and even that was not enough. Those who stayed bought the claims of those who left. Nobody plows here who does not have to. Plowing is how a dune is handed back to the wind. In the drought years of the 1930s, when the southern plains climbed into the sky, this quarter of Nebraska turned brown and a little ragged, but its sod was never broken and its hills did not take off. Everyone who works this ground knows which side of that line the living depends on. The grass is the crop; the cattle only harvest it.

The grass keeps more than hills. Rain falling on sand runs almost nowhere; it filters straight down into the great aquifer beneath the plains. Where the water table rises into the valleys, the country opens into wet meadows, round shallow lakes and reed beds — hundreds of them, each a surprise after miles of dry slope. Ranchers cut and stack native hay from these bottoms every summer, so the grass of the meadows feeds the cattle through winter while the grass of the high dunes holds the land underneath.

The Dismal River carves through the dunes, clear and cold, and toward Halsey the government once tried to grow a forest out of sand. A block of ponderosa pine stands there, planted by hand under an older idea of improving the plains. It is a curiosity — a green square on a country that otherwise refuses trees. It takes a century and a federal nursery to hold a few thousand acres of pine, while a few feet of root and leaf hold an ocean of dunes alone.

By late afternoon the light runs long and the hills go gold. The wind does not quit at sundown so much as set, and the grass straightens slowly, one blade then a thousand. Frost will be back before morning; below it, out of the reach of the wind, the roots are still at work. They have held through drought, fire, the hooves of bison and the cold of ten thousand winters. The dunes are asleep. It is the grass that stays awake.