It underlies the celebrated cathedrals of the world. It underlies the Pyramids of Giza, the Great Wall of China, the temple complex at Angkor Wat in Cambodia, Jerusalem’s Dome of the Rock, Thomas Jefferson’s Monticello, the American South’s untold Civil War battlefields, and even historic St. Andrew’s Roman Catholic Church here in Roanoke. It underlies every home in the Valley, every parking lot and highway, every skyscraper and mall, every tennis court and golf course, every college campus, and every rock and blade of grass. It underlies the creations of humanity throughout our errant history. From prophet to plumber, it underlies the footsteps of every person who has walked the planet from the dawn of time.
Though it’s constantly underfoot, we probably know more about other parts of the galaxy than we do about it.
What is it? Dirt. It’s what my colleague William Bryant Logan called “the ecstatic skin of the Earth” in his 1995 book by the same title.
Dirt is a Lilliputian world of biocomplexity. It’s not just pebbles or sand associated with a bunch of rotting flotsam and jetsam – though it’s often taken for granted or summarily dismissed as something “dirty.” Collectively, it’s a gas-and-mineral matrix along with the manure of animals, fragments of plants, and all sorts of living and dead things. A thimbleful of rich Roanoke dirt can hold 1 billion bacteria, several miles of fungi, several thousand protozoa, several hundred nematode worms, and much more! One thimbleful! How many thimblefuls of dirt are there in the mountains and valleys of the Roanoke region? Dirt is an awe-inspiring, integrated mix of life and nonlife descended from long-ago stardust set adrift in an ancient galaxy. It’s a tiny world burning hot underfoot as a living system.
Sadly, too often we let it wash away with every storm event in the Valley. Through the scars of development or neglect, we let rain and snowmelt carry its precious essences unrelentingly into our local streams and rivers to pollute faraway Batchelor Bay in North Carolina’s Albemarle Sound. Imagine the careless erosion along the Roanoke River’s 410-mile-long journey from its headwaters in the Blue Ridge Mountains to the Outer Banks. You can see it when the river turns brown after our major storms. In a 2009 paper from the Geological Society of America, researchers described the lower Roanoke River as “net depositional with a surplus of ~2,800,000 cubic meters per year.” That’s a lot of upstream movement of dirt downstream during a single year! Of course, at its extreme, erosion on Earth’s surface created the Grand Canyon and other wonderful geological features. But who wants another Grand Canyon cutting deeply from Virginia southeast across the Piedmont into North Carolina?
Every discussion about dirt will invariably involve a question about humus. Author and colleague William Bryant Logan wrote of humus as that “pure black acrid matter having a texture like a cross between cotton candy and damp sawdust. This is the stuff from which all life on the land is born.” It’s the uppermost layer of dirt where decomposition has gone into hyperdrive. Like a primordial soup, humus is the crumbly wet alchemy of pre-life that spawns the microbes, worms, and microarthropods essential for nutrient cycling. Logan argued that the words, humus and humility, are derived from the same root meaning “of the ground, lowly.” I relish this shared etiology. It reminds me of the humbling words spoken by Christian priests during the liturgy for Ash Wednesday to congregants as they are marked individually with the sign of the Cross in ashes: “Remember, you are dust and to dust you shall return.” It is a supremely mortal moment in the religious service that links our humanity with Earth’s ecstatic skin.
Let me close with quotes from two of my favorite politicians, men who witnessed firsthand the imperative to steward a nation’s dirt: Franklin D. Roosevelt (1883-1945) and David Ben-Gurion (1886-1973). In the midst of the “Dust Bowl,” in his 1937 letter to all state governors, Roosevelt wrote: “The nation that destroys its soil destroys itself.” David Ben-Gurion, Israel’s first prime minister, noted in 1951, “The soil is the source of life, creativity, culture, and real independence.” Of course, one of Ben-Gurion’s goals was to re-green the desert, a national strategy for Israel still in effect. Dirt is Earth’s layered epithelium through which courses the nutriment from life’s ancestors to sustain present-day biodiversity. Nurtured and conserved, it is also the foundation of independent peoples everywhere. Dirt represents a thimbleful of humility that we can offer to generations to come: a witness to all our achievements, great and small. We are a wealthy nation when we leave our soils enriched and living for those who follow us. In his 1949 book, A Sand County Almanac, the great American land ethicist Aldo Leopold called land a “sustained circuit like a slowly augmented revolving fund of life.” Like every healthy fund, dirt requires continued and diligent investment. Let’s celebrate a dirty – rather than dirt-free – world!