How readily do we manipulate our soil? We rearrange and restructure. We pump it full of chemicals, we flood it, we drain it, On its health the fate of empires has rested. Yet we avoid it. In our cities, rivers of concrete keep us from its touch. Naked, it tends to offend the eye. But a close look reveals that the soil is an essential bridge between the rock below and the life above. It is dynamic and vital, and far to easily, and frequently, abused.
“I just farmed myself broke. I was farming land that had no business having a plow in it. Seven years ago I had $300,000 and a dream — I wanted to be a farmer. My wife and I spent 13 years in Saudi Arabia, saving that money. We came home because we thought there was something here, and we dug for it. In the end we lost nearly $900,000. We double cropped, wheat and soybeans. But with the high price of fertilizers and lime, there was no way to get our money back. The last two years I was just farming for getaway money. No way a farmer can make it on this land, and most of them don’t have other options. Me, I sell insurance now. We came up from the bottom, and we’re fixin’ to come up from it again”
Marion “Bobo” Green
A familiar lament, this story from the heart of Georgia’s old cotton country, where the soils are old, weathered, and poor. As thousands of similar cases each year confirm, more than capital and enthusiasm are necessary to make a go of it as an American farmer. Understanding of soils and their capabilities is at least as important.
In 1931, as the Depression strangled the economy, drought began baking the Great Plains. On April 14, 1935 (Black Sunday) a clear, warm day suddenly grew chill as a dark curtain of rolling dust advanced across the plains. Behind it came Robert Geiger an Associated Press reporter, whose story was about the “dust Bowl” would forever brand the southern High Plains. For almost a decade, the longest drought in memory, the plains cooked and blew, dusting ships 300 miles out in the Atlantic. Harold Hogue returned from a visit in Oklahoma to his wheat farm at Dalhart, Texas. “It looked like a desert. That wheat was dead. I climbed over the fence and got one hell of a shock, there was so much electricity in the air from the dust storns.” Hogue lived in a shack wallpapered with cardboard, its window a truck windshield. “The first norther come right through the one-by-twelves. My quilt was covered. If I was on the tractor, my eyes would ball up with mud until I couldn’t see the furrows.” When hogue told me this, I was sitting in the living room of his spacious home looking out at his tennis court. From everything I had read of what the 1930s had done to the upper Panhandle of Texas, I expected Dalhart to be tumbleweeds and steer skulls. But Hogue’s neighborhood of wealthy farmers could have been lifted out of Beverly Hills. He had hung on through the drought, plowing for others and putting his earnings back into land no one else wanted. He dragged railroad rails over the dunes and moved dirt for 20 years, gradually leveling his fields. Wary about dryland farming, he drilled down to water trapped in the vast Ogallala aquifer during the Pleistocene. He now irrigates 20 verdant square miles of wheat, sorghum, and pheasants. His pumps run on natural gas. He winters in Palm Springs. His pickup is a coupe de Ville. Roughly half the irrigated land in the United States is in the Great Plains, most of it watered from the Ogallala. The Sand Hills of Nebraska lie over its deepest part, though shallow beds of the aquifer reach far down the Texas Panhandle. Irrigation grows lush plants, giving organic matter to soils that once got it from short-grass prairie. As long as the Ogallala holds out, the soil will be enriched. But Hogue is not sanguine about the Texas end of the aquifer and the costs of pumping:
“A lot of people say we’ll never have another Dust Bowl. The hell we can’t. With the price of natural gas, we could be back to dryland farming soon. A lot of farmers already are. You have to have moisture to tie this soil together. If not, it’s just like White Sands. It’ll blow.”
From all the soil erosion stories I had read recently, it seemed that the corn belt was pouring into the Gulf of Mexico and the Great Plains were blowing away. Reporters would troop down to the delta, peer into the muddy Mississippi, do some quick calculations, and announce how much of Iowa or Illinois had just been sent to the sea by farmers. As Bob Ruhe drove e across the corn belt, I asked him what he thought of this man-made disaster.
“That’s bull!” he shouted, pounding the steering wheel. “Most of the stuff is still in the watershed, at the bottom of the hill.” Bob Ruhe is a geologist, a geomophologist, and the acerbic Yahweh of soils and landscape evolution in the Midwest. He is a lean man, tightly wound, his hair short and white, and his assertions vehement. He sets his alarm by geologic time. “I writhe when I sear ‘man-caused erosion,'” he said. “That’s dogmatic and misleading. Erosion in the Midwest during the past 10,000 years has been incredible – far higher than anything man caused. Sure you can see examples of guys mistreating the land. But to generalize from that is false.”
Erosion may seem a rather straightforward problem, but soils are complicated, and between the apocalypse and Ruhe lies much conflicting opinion. With some exceptions, erosion gradually depletes soils, and nearly a billion dollars each year in polluted and sedimented rivers and lakes. Soil erosion is serious, but not everywhere and not for the same reasons.
Not until 40 years after the Dust Bowl dis the U.S. Soil Conservation Service (SCS) begin to determine systematically how much soil is eroding in the United States. The SCS estimated that in 1977 we “lost” about three billion tons of soil from fields under the plow; roughly two-thirds of it washed, the rest blew. But where it goes and how much its departure damages soil productivity, no one knows with much confidence.
I asked M. Gordon Wolman, an eminent geomorphologist at the John Hopkins University in Baltimore, how much we should care. “It depends on where in the U.S. you are and whether your time scale is long or short,” he said. “Agriculture has perhaps doubled the rate of geologic erosion, but, as Ruhe indicates, you have to be careful what area of the country you talk about. In places we have made a mess of it, but for the U.S. as a whole, erosion is not killing us. Could it? Probably not. Is it important? In some places absolutely.”
The 1977 SCS estimated show that erosion in this country was patchy. Texas alone accounted for one-fifth of all cropland erosion. Rates well beyond what the SCS believes soil can tolerate were confined to about 10 percent of the landscape: the High Plains of Texas, the Palouse Hills of eastern Washington, and the silty hills bordering the Missouri and Mississippi Rivers from western Iowa almost to the Gulf.
On the Great Plains, speculators and hard-pressed ranchers have been plowing up hundreds and thousands of acres of fragile grasslands to grow wheat – more than half a million acres recently in eastern Colorado along. These soils easily blow when it’s dry, and prolonged drought on the plains, like the one that led to the Dust Bowl, is only a matter of time.
Farmers helped aggravate erosion when they leaped suddenly into the export business. In 1972 massive sales of American grain to the Soviet Union sent prices souring, and by the end of the decade the value of the U.S. farm exports had jumped more than fivefold. A third of our croplands now produce for markets over-seas. Chasing the price of grain, farmers plowed up an addition 60 million acres in the 1970s, much of it once protected beneath grass, some of it steep and erodible. Few farmers still kept livestock, so they stopped rotating their fields in pasture and hay and grew erosive soybeans and corn year after year. And from the factories had come big iron: 16-row cultivators and moldboard plows, and moister discs. No longer a modest red tractor with a coil spring under the seat, 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 tap, and enough horsepower to plow straight through hills. Big gear didn’t run easily on contours, and terraces built to slow erosion got in the way Earl Butz, then secretary of agriculture, urged farmers to plow “fence-row to fence-row,” but they even plowed out the fence-rows, the terraces, almost 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 soil 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 spectacular, as in the Grand Canyon, we enshrine it 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 difference to trace sediment to its source. Luna Leopold, former chief hydrologist of the U.S. Geological Surve, says that much of that sediment comes from easily erodible shale’s that the muddy Missouri has been hauling off the Great Plains since the Rockies came up.
“It’s really the geological 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 forests. Clear-cuts don’t explain all that sediment, much of which comes from landslides.”
You view soil erosion differently depending on where you are in the country. What may be a crisis to an Ozark family only inches from limestone may be only an inconvenience 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; Redlands, California. Soils thin as crackers, organic mucks that wrinkle the nose, soils of sand, rich alluvial soils, oil soils, young soils, buried soils, shrinking and swelling clays that tilt telephone poles toward the road like savers at a naval wedding.
Without soils there would be no grass, no cows, no bread, no us. When we think that man runs the show on earth, we might recall that earth is mostly rock and life only a veneer on it, sustained largely by a sheet of soils derived from and covering the rock. According to physicist J.D. Bernal, life might have fizzled at sea, where it began, had not the first organic molecules found clay crystals to fasten on to, washed thee from weathered rock.
“Nature beats up the landscape,” says Dick Arnold, director of the soil survey division for the SCS. “But man accelerates it. Soils are important to survival. Lets not beat them up if we don’t have to.”
Soil begins as rock. Pikes peak, Half Dome, the bedrock beneath my yard in Maryland, all are soils in embryo. Water is the agent, exfoliating boulders like shell of a hard-boiled egg, running over rock, under it, reducing it to sand, silt, and microscopic particles of clay. Water bathes the rubble in carbonic acid, rearranging the chemistry of the rock. This releases minerals to be held by clay and organic particles as nutrients for plants. Most soils are about half mineral, the rest air and water mixed with a little organic matter – the remains of dead animals and plants. At a roadcut soil shows its profile of A,B, and C horizons, or what farmers call topsoil, subsoil, and the stuff below. Organic matter usually accumulates in the A horizon, where seeds germinate. It may not, below that, the B horizon collect clay, iron, and aluminum. The C horizon is weathered rock, the parent material from which soil forms. There are soils that stand this little lecture on its head, for soils are as varied as the rocks, climate, topography, organisms, and length of time that create them.
Bacteria – and rain and lightning – pull nitrogen from the air. Plants take root, suck up nitrogen and the minerals leached from rock, throw seeds, and die. Worms, ants, gophers move in and rearrange the soil, opening it up and giving it air. Multiplying beyond count, microbes help release nutrients from dead plants for use by live ones by decomposing organic matter into humus, a dark adhesive embracing clay particles, giving topsoil the feel of bread crumbs and the function of a sponge. Roots can now more easily get water and grow. A soil evolves. Except for mucks like the Sacramento Delta, most soils have little humus, maybe 6 percent under prairie and almost none in the deserts. But humas is far more important than its proportion in soils indicated. By manuring or plowing under a cover crop like clover, a farmer can return nutrients to the soil for his next rotation of corn.
Plants are nourished by inorganic minerals, so the corn doesn’t care if nitrogen is converted by bacteria from manure or scattered from a bag of commercial inorganic fertilizer, but the farmer may see the difference in his cash flow. About half our 8.6 billion dollar fertilizer bill is for nitrogen, most of it in the for of ammonia made from air and natural gas, making farmers all the more vulnerable to the volatile prices and politics of oil and gas. More important, humus helps topsoil hold water against a dry spell, and by absorbing runoff, it slows erosion. But left unprotected on a hillslope, topsoil gradually gives up its organic glue to a thin sheet of moving water. “As slopes erode,” Klaus Flach, an SCS scientist told me, “you get more runoff and less water infiltrating the soil. Out in those areas of the country where water is critical, the crops get starved. We really saw it in the 1983 drought.”
The deserts are fertile because there is little rain to leach away the mineral nutrients. That’s why Arizona’s Salt River Valley bloomed when it was irrigated, and why salt still plague it. The glaciated Midwest is productive because its soils are young, from rich sedimentary rock, and its climate favored prairie grasses whose mats of roots made deep humus.
Pity the Pilgrims, who stepped ashore to confront a wall of forest and a cruel joke beneath the trees. New England stands on granite. Except for the silted beaver meadows and alluvial valleys like the Connecticut, the glaciers left the colonists only a thin mantle of hilly, stony soil. The Southeast also was of mineral-poor rock, and it had weathered too long in the rain. Save for the river deltas and the limestone valleys, its old soils where largely pooped out before the first ax rang in the forest. My yard on the rolling Maryland Piedmont of Suburban Washing, D.c., is of that tired soil. The rock came up a quarter of a billion years ago, as the Appalachian mountains rose into the rain and were reduced to hills, the debris washing onto the coastal plain.
For millions of years rain leached minerals from soils of the southeastern US, making them acidic and salting the sea. The rain reacted with carbon dioxide to release hydrogen ions, the source of acid, that replaced nutrients in the soil. In the arid West, with little rain to leach the minerals, salts crusted on alkaline fields as on the rim of a margarita glass. My azaleas prefer acidic Maryland, but most plants like neither extreme. They seek neutrality.
The colonists opened the Piedmont forest and dropped seeds in the sunlight. Crops did well for a few years, then thinned. Threes could exploit these poor soils by recycling nutrients from dropped leaves back through the roots, but fertility was all in the humus and not in these tired kolinitic clays. With the trees gone, the humus lost its fuel. Stored fertility went up shoots of tobacco, and, so to speak, up in smoke. Deep gullies crawled up hillsides of tobacco and cotton, subdividing farms. Sediment went down hill like melting sugar, filling streams and swamping bottomlands, provoking Patrick Henry to write: “He is the greatest patriot who stops the most gullies.” It is no wonder the settlers had an itch to head west.