IOWA - Portrait of the Land - Soil: A Fertile Filter

Photo by Natural Resources Conservation Service.

UNCLE MERRIS
ON THE STRUCTURE OF THE SOIL

Essay by Michael Carey

Yesterday a fog rolled in and a soft drizzle turned into rain some fifty miles from here. So today, in response, the creeks have risen. And in the middle of the soggy bottom a huge, wet, silver snake begins to shimmer and shine. "The river remembers its bed," Uncle Merris always told me. "The Corps of Engineers can straighten all the banks they want, but the river remembers. Ask any farmer and he'll tell you."

I had gotten stuck, almost buried, in gumbo one too many times to doubt him - the black glue sticking to the axles and wheels on my tractor and disc and then hardening. "It's worse than cement," he'd remind me, "keep it off of your equipment. Wash everything as soon as you muddy it or you may never be able to get it clean." He knew the power in the thing he was tending. What dark forces lay hidden in the memory of the soil. He worked it all his life, but he feared it too and respected it. "Wasn't the dark life of the rich soil, the richest in the world, death really and beautiful decay? Hadn't billions upon billions of living things laid down their short lives for us to stand on and in and to plow? Isn't that what we mean by organic matter? Wasn't every farmer in the whole world trying to make money, in the end, from the lives and sacrifice of others? Wasn't everything in this fertile land floating on a sea of death? If for one second we realized how many lives were sacrificed to help us, now, make a living, we would tend the grave more carefully. We wouldn't let one sacred ounce of it slip away down the Missouri or give it away, as so many have before us, to the distant swamps of the Mississippi Delta."

"One half of prairie earth," he said "is air. One half of the earth we stand on is sky. Heaven has come and made the ground fragile. Ask the wind and the water and the worms. Ask all the microorganisms that breed and seed and feed on what feeds you. Step knowingly!"

Once again the white corn and ripening beans bend themselves when they hear the distant roar roaring closer. In these painfully changing times, there is nothing stopping whatever happens. Whatever happened yesterday fifty miles north and east of here matters desperately today to me and to you, to people who may have never left home, or looked up and wondered what it is that is coming, who put this food in our hands, what in God's name they were doing on this earth so long.

On a warm May day, when the wild plums are blooming and the oak leaves have begun to unfurl, plunge your fingers into the rich soil of an about-to-be-planted corn field. Or crumble the tiny clods as you poke the last potatoes into the garden plot. Or brush aside the moldering leaves as you pluck a fresh morel at the edge of the woodlot. Then breathe, deeply.

Farmers, gardeners, foresters, and mushroom hunters love the aroma of moist, fertile soil. Children instinctively run their fingers through it; they may squeal with delight as they feel, throw, explore, and taste the very ground they're sitting upon. Just as infants snuggle for comfort in their mothers' arms, we all feel drawn to the earth's soft, living, fragrant skin.

In Iowa, we see that connection clearly, daily. More than half of our state is prime farmland - the rich, black soil that has become the standard for agriculture. Iowa's special land can grow some of the best crops in the world. Our economy, literally and figuratively, is rooted in the soil. Many of us can trace our heritage to the farm families who have worked that precious soil for generations. Even though we have manipulated the soil to fit our human wants and needs by replacing diverse prairies, wetlands, and forests with orderly fields and straight roads, it's still the basis for our livelihoods.

We may grieve, therefore, when we see that soil mistreated. Our stomachs may tighten when we see a bulldozed construction site, the raw scar of a gouged stream bank, layers of windblown topsoil in the winter snowdrifts, or gullies carved between the corn rows by a heavy rain.

By the same token, we value healthy soil and land. Farmers are understandably proud when neighbors admire their thriving cropfields. Naturalists praise the diversity of a prairie remnant, the majesty of a mature forest, or the richness of life in a wetland. City dwellers may long to walk in a park, sit in the shade of an oak, or splash in a stream that is the lifeblood of our land. At every meal, we nourish our bodies with the bounty of our soil. Thus, in so many ways, the quality of our lives really depends upon the quality of our soil.

Still, sometimes, we take soil and its services for granted. We may not fully appreciate this thin veneer of land - just the upper few feet - that allows life to exist on Earth. Perhaps we don't realize that nature's forces have manufactured that soil from "parent" earth materials. Soils form slowly, in response to the weather, the lay of the land, and the presence of living and decaying organisms. We struggle to comprehend the 200 to 1,000 years that it took the water, wind, ice, animals, and plants to transform those raw materials into just one inch of topsoil.

We may forget that the soil that enables us to sustain life is itself an extraordinary living community. A spoonful of soil may contain more than 6 billion micro-organisms, a number equal to the human population of the Earth. The earthworms in a single acre of soil can move and aerate 100 tons of soil annually. They may dig 800,000 tunnels, which carry rainwater into and through the soil. Snakes, turtles, insects, and small mammals also burrow into the soil, cultivating it from below. Larger animals walk on it, dig in it, and rely on its plant products to survive.

Truly, that soil community embraces and physically supports everything that lives on our land. Plants not only sink their roots into the soil, they also draw nutrients from it. Fertile, stable, well-managed soil nurtures a rich plant community that in turn feeds abundant animal life. Those plants also produce life-giving oxygen and use carbon dioxide from the air to produce more green matter. Locked up in that vegetation, then stored as humus in the soil, the carbon is not released into the atmosphere, but is sequestered. This reduces the greenhouse effect and the potential problems of climate change.

The soil's intricate matrix of roots and decaying vegetation and minerals and micro-organisms acts like a sponge to soak up rainwater and snowmelt. This living sponge also can cleanse, recirculate, renew, filter, and store that water, then gently release it again to plant cells or into clear streams. The remarkable soil community, this natural purification system, also neutralizes our wastes, breaking down toxins into harmless substances. And when plants or animals die, the soil recycles them into new soil, to grow new plants that feed new animals.

Soils often are complex and unique. In fact, scientists have identified at least 11,000 different soils in Iowa. These soils vary in how they were formed, their physical structure, their landscape position, their ability to hold water, the plants and animals they support, how easily they erode, and their chemical compositions. Each soil behaves and looks differently, has distinct capabilities and limitations, and ultimately is influenced by a host of factors acting upon it.

Some soils work hard to help manufacture food and fiber used by people. A few soils cling precariously to steep, rocky slopes, yet they still yield scenic beauty and wildlife habitat. Other soils have left the state, swept away by the winds and waters of change. Like people, soils that lose their health may no longer contribute to the community, but with proper care, they can remain vigorous and productive.

But the soil community has been slipping away. In the 150 years since we began intensely clearing, plowing, and cultivating the land that once supported our prairies and forests and wetlands, the steeper croplands have lost about half of their original topsoil. Erosion has stripped off the rich surface layer, including organic matter, nutrients, and living organisms. The displaced soil becomes just sediment - dumped into streams and swept into ditches or the atmosphere. That soil had been forming for thousands of years, yet in just a century and a half, we've depleted 50 percent of that original precious resource on our hilly lands.

We've also stamped the soil, and the landscape, with the imprints of our human activities. People build roads and like straight lines. In place of a mosaic of diverse vegetation, controlled by nature's flowing contours, we've girdled the land with a geometric pattern of highways, fields, fences, and utility lines. Instead of leaving the soil anchored in permanent plant cover, we now till and plant the fields, harvest the crops, then often leave the earth exposed to the elements for half the year.

Even the soil that stays in place can lose its quality. Nutrients may leach out, or salts can accumulate. Chemicals can kill soil microbes and interfere with biological activity. Heavy equipment or livestock can pack down soil layers and hamper water infiltration. Thus, runoff and flooding increase, leaving less water available for plant growth. Erosion and intensive cropping can destroy organic matter and diminish a soil's vitality, productivity, and water-holding capacity.

And when the soil suffers, the land suffers. Indeed, we all suffer. Crop yields fall. Sediment clogs road ditches and culverts, carries contaminants, pollutes drinking water supplies, damages fish and wildlife habitat, and degrades recreational lakes and streams.

Fortunately, many good stewards treasure every particle of our soil. They guard its health, appreciate its crops, respect its integrity, and protect it from abuse and neglect. They know that healthy soil - whether it grows corn, oaks, bluestem, or cattails - is the foundation of our very existence.


Shooting star	Soil: A Fertile Filter	Jack-in-the-pulpit	Luna moth

Photo by Gene Alexander.		Photo by Lowell Washburn.

Photo by Natural Resources Conservation Service.		Iowa's annual corn harvest and checkbook balance reflect the ingenuity of farmers, the judicious application of farm chemicals, government farm policies, environmental regulations, profitable conservation measures, and the strength of a partnership with land, soil, and water resources.

Photo by Stan Mitchem.		Photo by Natural Resources Conservation Service.

Photo by Brian Button.		Soil loosened for cultivation can be lost to wind erosion (left), water erosion (below left), or gully erosion (above, left and right), and can enable the escape of unused agricultural chemicals into the water and air (below right).