“Predictably—and understandably— more pressing problems than saving dirt usually carry the day,” writes David R. Montgomery. But as his new book, Dirt: The Erosion of Civilizations, details, we are losing the brown stuff far, far too quickly. Unlike maritime dead zones and radical climate change, cases in which we have little historical knowledge on which to draw, we do have some sense of what happens to civilizations that abuse and lose their dirt. The book’s conclusion takes little comfort in history: “Unless more immediate disasters do us in, how we address the twin problems of soil degradation and accelerated erosion will eventually determine the fate of modern civilization.” (Never mind the echoes of that useful old tip “If nothing else kills you, cancer will.”)
For terrestrial life forms, dirt is where it all begins. It is “the skin of the earth—the frontier between geology and biology,” a thin, fragile living blanket that covers a hard, rock planet. Early on, Montgomery, a professor of earth and space sciences at the University of Washington and author of King of Fish: The Thousand-Year Run of Salmon (2003), examines the organic and geologic processes that produce soil and cause it to erode. Given enough time, these competing tendencies tend to bring about an equilibrium in soil characteristics and soil type specific to a given place. Agriculture, of course, alters things.
With more thoroughness than narrative snap, much of Dirt is given over to an environmental history of civilizations, which wax and wane over hundreds and thousands of years as they plow up their topsoil, push their land to its limits in order to feed burgeoning populations, and watch the exposed dirt wash or blow away. It then becomes a matter of moving on to steeper, poorer land, importing food (as in the case of imperial Rome), melting away into the jungle, or slaughtering one another over rare arable land. This dirt’s-eye-view of history provides an interesting perspective on a vast range of topics, from the vanishing commons and the rise of private estates in Europe to the drive to colonize the Americas, from slavery and the Industrial Revolution to floods and famines in nineteenth- and early-twentieth-century China. And no book on dirt can pass lightly over the Depression-era Dust Bowl or its lesser-known Soviet counterpart.
Montgomery decries the loss of soil husbandry, the intelligent and long-term stewardship that good dirt requires if we are continuously to extract food from it. Instead, factors such as population growth, a variety of economic ideologies, absentee land ownership, and the profit-driven imperatives of fossil-fuel, agrochemical, and machinery producers continue to press— worldwide—for maximum immediate yield, leading to erosion rates orders of magnitude higher than that at which soil is formed. What is needed, writes Montgomery, is agroecology in place of agrochemistry—a matching of practice to place, an intelligent mimicry of nature in place of genetic jiggering and the ever-less-effective application of ever-dwindling petrochemicals. Urban agriculture, efficient small-scale organic farms, and no-till methods on large-scale farms point a way forward. With the world losing an astonishing 1 percent of its arable land each year (that’s from a 1995 study, so say good-bye to 11 percent of it and add another billion mouths to feed), Montgomery warns that it is time to treat soil “as a valuable inheritance rather than a commodity—as something other than dirt.”
