National Geographic : 1984 Sep
the seat, the wind up your shirt, and the manure spreader flinging chunks past your ears, but a four-wheel-drive behemoth with a wraparound cab, Loretta Lynn on the tape, and enough horsepower to plow straight up hills. Big gear didn't run easily on contours, and terraces built to slow ero sion got in the way. Earl Butz, then secre tary of agriculture, urged farmers to plow "fencerow to fencerow," but they even plowed out the fencerows, the terraces, al most everything but silos. So-called clean farming set a lot more soil on the move. But where did it go? "We soil scientists ought to hide our heads in shame," William Larson, head of the soils department at the University of Minnesota, told me. "We had all this data on erosion losses, but we didn't know what it meant. I'm trying to get that word 'loss' out of my vocabulary. Soil isn't lost as such. Very little of it leaves the immediate landscape." Erosion has been lowering the mountains and cutting and filling the valleys since the first raindrop hit the ground and the wind began to blow. When erosion gets spectacu lar, as in the Grand Canyon, we enshrine it Battling the sodbusters, ranchowner Edith Steiger Phillips (right) helped spark a popular movement now being debated in Congress. On her property nearKeota, Colorado,she displays the dirt that buriedher grazing land up to the fence tops after 10,000 acres of neighboringrange was plowed out and succumbed to the area'snotorious winds. Fightingmad, she sued, claiming: "It's not an act of God. It's an actof greed. God doesn't have a plow." Millions of acres of western grasslands have recently gone under the plow, largelyto grow wheat. Sodbuster legislationwould deny crop subsidies to farmers who breakfragile new ground without following conservation practices. One experimentalapproachto hold down soil is used by HaroldThurow (left) of Ault, Colorado,who spreads hisfields with onions, hoping their weight will hold the soil between plantings. as a national park and go downstream to farm the sediments. The Mississippi River pours more than a quarter of a billion tons of sediment each year into the Gulf of Mexico. Undoubtedly, some of Iowa's topsoil is in that cocoa, but it's difficult to trace sediment to its source. Luna Leopold, former chief hydrologist of the U. S. Geological Survey, says that much of that sediment comes from easily erodible shales that the muddy Mis souri has been hauling off the Great Plains since the Rockies came up. "It's really the geology and climate that count," he says. "One of the largest sediment producers in the country is the Eel River of California. It's not clear why, because the Eel is covered with redwood forest. Clear cuts don't explain all that sediment, much of which comes from landslides." You view soil erosion differently depend ing on where you are in the country. What may be a crisis to an Ozark family only inch es from limestone may be only an inconve nience to a farmer in western Iowa on 80 feet of fertile silt. There are upwards of 30,000 different soils in the United States, which give identity to Black Earth, Wisconsin; Do We Treat Our Soil Like Dirt?