Where The Sky Began: Land of the Tallgrass Prairie

5. Prairyerths

5 Prairyerths INHuckleberry Finn, Mark Twain has the Child of Calamity sitting there on the raft and telling about rivers. Not just any rivers, but the clear Ohio that drained the timbered country and the muddy Mississippi that drained all that prairie country . The Ohio just had no body to it at all, compared to the Mississippi, which was good, thick, nutritious water and if a man drank it he "could grow corn in his stomach if he wanted to." The Child of Calamity knew this, because: "You look at the graveyards; that tells the tale. Trees don't grow worth shucks in a Cincinnati graveyard, but in a Sent Louis graveyard they grow upwards to eight hundred foot high. It's all on account of the water the people drunk before they laid up. A Cincinnati corpse don't richen a soil any." The Mississippi is all that nutritious because it drains such mighty nutritious land -and even carries some of that land along with it just to keep its strength up. It's land that the prairie farmers have always bragged on, and they still yam about it. Herb Shriner used to say that folks around his part of Indiana weren't much worried about the Bomb. They figured that any bomb dropped on Indiana wouldn't do much but just lay there and grow. That's what everything else did. And just about everything should-for anything planted in the deep mellow prairieland lies in some of the richest soil ever known, a bank of incredible fecundity that produces nearly half the world's corn, much of the wheat and soybeans , and a billionweight of meat each year, and radiates a deep and steadypower that helps drive the work of a half-billion people. The energies of our other black fuels, coal and oil, are rather modest, short-term sources of power when compared to the great black loamsof the American midlands. Prairie loams, like all their poorer relatives, spring from ancestral materials that are derived from rock. One of the commonest parent materials is loess, the rock flour that was ground in the mills of the Pleistoceneice-rivers and left behind in outwash deposits.Fine-grained and light, it was easily picked up by wind as aeolian dust and often blown great distances before being dropped in beds that sometimes grew hundreds of feet thick during centuries of sheet erosion. Named for the Loess district of Germany where it was first studied, and pronounced "luss," it has few peers as a soil base -light, fine-grained, and containing a complex wealth of plant nutrients whose major component is often calcium carbonate. It's odd stuff with a strange ability to stand in smooth vertical banks when cut by road-buildingmachinery, although it loses this ability once it is disturbed, loosened, and piled elsewhere. At first glance it may appear to be just another clay cutbank, but its fine texture, lightness, and high permeability by water are unlike any clays. Airborne loess was often trapped by elevations and wooded streambanks that ran generally north and south at right angles to the prevailing westerlies, and the deepest deposits are usually along such west-facing streamsides. This is the material comprising many of the eastern shoulders of midwestern rivers-and forms the "west coasts" of Wisconsin , Illinois, and Iowa. The timbered loess ridges above some prairie streams were called "white oak soil" in the early days of settlement and were eagerly sought and cultivated. It was fertile land and easily tilled, but tended to "wear out fast" a character probably due to reduced soil humus under trees, and the high permeability of the loessian base that allowed organic nutrients to leach rapidly away. Loess is probably the most extensiveparent material under the world's northern prairies, with glacial till ranking second in importance. Ranking still lower in order of importance are silt deposits from streams and ancient lakes, wind-and-waterlaid sands, soft shales, and sandstones. Glacial till is the vast load of rock debris brought down 110 THE PLACE from the north and dumped in great beds and moraines. Much of the northern prairie today is underlain with this unreconstructed glacial drift -broad deposits of boulders, gravels, sands, cobble, and clay that may average one hundred and fifty feet thick, often penetrated by ground waters that run in deep, cold aquifers. Over much of this lies...