Book review of Dirt: the erosion of civilization

Preface. On average civilizations collapsed after 800 to 2,000 years because they’d destroyed their topsoil.

Today, industrial agriculture is doing this far faster – in most of the United States half of the original topsoil is gone from the richest Midwestern farmland.  This is because industrial farming techniques erode and compact the land much more than men and horses ever could in the past.  Monoculture crops of all kinds, especially corn and soy, have wide rows that enable soil to wash or blow away, and require more pesticides that kill the soil biota which could have provided natural immunity.  Above all, over half of farms are owned by clueless businessmen who lease the land to farmers who must make as much money as they can to earn a living.  Preserving the land for future generations is not a priority for them, this isn’t their land.

The bedrock of any civilization is food and water.  You’d think the top priority of nations would be ensuring farmers were taking good care of the land because this history of erosion is well-known and has been for centuries.

Related article: “Peak soil: Industrial agriculture destroys ecosystems and civilizations. Biofuels make it worse“.

Alice Friedemann  author of “When Trucks Stop Running: Energy and the Future of Transportation”, 2015, Springer and “Crunch! Whole Grain Artisan Chips and Crackers”. Podcasts: Practical Prepping, KunstlerCast 253, KunstlerCast278, Peak Prosperity , XX2 report


David R. Montgomery. 2007. Dirt: The Erosion of Civilizations.  University of California Press.

Both George Washington and Thomas Jefferson commented on how poorly American farmers treated their land.  Washington attributed it to ignorance, Jefferson to greed.  Since the principles of good land management were known for hundreds of years previously in Europe, Jefferson’s harsher view is no doubt the correct one.

Tobacco is partly to blame for the very early loss of topsoil in America.  It was a very lucrative crop, worth about 6 times more than any other crop, plus it could survive the long journey to Europe.  But tobacco crops expose the soil, which washes or blows away in storms.  If storms don’t ruin the soil, tobacco will — it uses 10 times more nitrogen and 30 times more phosphorous than the average food crop.

Tobacco exhausted the land after about five years, so to some extent it was responsible for the continual migration of settlers westward.   Slavery magnified this trend.  Running a farm with multiple, rotating crops requires a great deal of fine-tuned attention.  Slaves worked reluctantly, just hard enough to not get beaten, so it was easiest to train slaves to work in huge mono-culture tobacco (and soil-depleting cotton) fields.

Montgomery makes an interesting case for topsoil being the reason the South started the Civil War.   President Lincoln took the middle ground of allowing slavery where it already existed, rather than banning it as so many wanted, but would not allow slavery to expand to new states.  The largest slave owners made more money selling slaves than growing crops.  If Texas became a slave state, they could double their money, and so the wealthiest slave owners started the Civil war to protect as well as increase their wealth by fighting for the expansion of slavery into new states so they could sell slaves for more money.

To this day, much of the land in the South is still ruined.  Instead of the thick black topsoil described by early settlers, the soil is thin and clayey, and sometimes missing entirely.

Absentee ownership has played a large role in soil exhaustion from the Roman Empire to the present day.  Tenants being paid with a percentage of crops or money are far more concerned with maximizing the harvest than protecting soil fertility.

Mechanization worsens matters.  Like slavery, mechanization requires single crops.  When farms became mechanized, the need for profits to finance the machines becomes more important than the soil.  Increasing debt to pay for machines led to 4 out of 10 farms disappearing between 1933 and 1968.

Large corporate farms are a type of absentee ownership that is particularly likely to foster erosion.  Huge debts need to be paid off on large pieces of farm machinery. The financial pressure to produce as much as possible to earn money to pay off the debt trumps soil conservation.

Mechanized farms are less efficient and profitable than smaller traditional farms because they spend a lot more on equipment, fertilizer, and pesticides.  Larger farms do not bring economies of scale to food production.  Small farms grow 2 to 10 times as much per acre as do large farms.  And because small farms use far less agrichemicals, antibiotics, and fertilizer, they don’t pollute the air, water, and soil as much as large farms do.

Yet the trend continues toward large farms, we’ve gone from 7 million to 2 million farms, with 20% of farms producing almost 90% of food grown in America.

This is because the $10 billion a year in farm subsidies goes mainly go to the largest ten percent of farms, which receive two-thirds of the subsidies. Farm subsidies were meant to support struggling family farms, but now they’re used to actively encourage large farms.

Montgomery points out that “Good public policy would use public funds to encourage soil stewardship—and family farms—instead of encouraging large-scale monoculture”.

Half the fertilizer we dump on the soil is used to replace the soil nutrients lost from topsoil erosion.  “This puts us in the odd position of consuming fossil fuels—geologically one of the rarest and most useful resources ever discovered—to provide a substitute for dirt—the cheapest and most widely available agricultural input imaginable”.

“Enough American farms disappeared beneath concrete to cover Nebraska in the three decades from 1945 to 1975. Each year between 1967 and 1977, urbanization converted almost a million acres of U.S. farmland to nonagricultural uses”.

Within 200 years, America has lost one-third of its topsoil.  At the rate soil was being lost in the 1970’s, it would only take a century to lose the rest of the country’s remaining topsoil.  Yet despite congress being aware of this, the government cut support for agricultural conservation by over half in the 1970’s.  Congress doesn’t get it —they think “why spend taxpayer money to save soil when grain bins are bursting?”

It’s hard to imagine anything worse than allowing the land to lose its topsoil, but there is.  Montgomery writes about how eight major U. S. Companies sold industrial toxic wastes as fertilizer to make money and avoid spending millions to dispose of it properly.  Heavy metals stay in the soil for thousands of years, preventing or stunting plant growth.

In the last chapter, “Life Span of Civilizations”, Montgomery discusses what needs to be done to protect the remaining soil for future generations.  So do buy this book and use the last chapter as a basis for letters of what to do and write your local and national representatives.  Plus alert your favorite environmental groups – agriculture is the most ecologically destructive force on the planet.

Anyone who’s read this far is probably devoted to many causes, but unless your cause is to return to hunting and gathering, I urge you to make preservation of topsoil and reforming agriculture your main cause!

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4 Responses to Book review of Dirt: the erosion of civilization

  1. Bernard Beveridge says:

    I purchased “Dirt” several years ago and have re-read it 3 or 4 times. It was so depressing to learn what a sad state so much of our farmland was in. By coincidence, just last week I finished David Montgomery’s most recent book (Growing a Revolution: Bringing our Soil Back to Life) which was published last July. In this book Mr. Montgomery details how a system of no-till farming, crop rotation, and cover crops can bring about seemingly miraculous transformations in soil “life.” I encourage everyone to visit his website to learn more about his books.

  2. Steve Bull says:

    I reside in what was once a thriving agricultural area on the outskirts of the Greater Toronto Area. In fact, our agricultural roots and ‘country’ lifestyle morivated our town council to adopt the moniker ‘Country close to the city’ a few years back. Unfortunately, as with most politicians, our council used this as a marketing scheme to attract business and population growth, paving over more and more of our region’s limited arable soil in the process. I have fought against this short-term profit-seeking in a number of ways but to no avail. Growth continues without pause with politician after politician stressing how great it is for everyone. I have come to the conclusion that we will continue on this dead-end path until the collapse that accompanies overshooting the natural carrying capacity of the environment happens. There are just too many variables in play and too much momentum to reverse things.

  3. Goran says:

    Also worth a link from here: “Farmers of Forty Centuries”. Free pdf on

    More than 100 years ago, King shared his insights from investigating Asian food production, where fields have been used for millennia. It is possible and the knowledge has been around for a long time…

    Thanks for the notification of the new book by Montgomery!

    • Shane says:

      Just knowing how to do something sustainably doesn’t mean it will be done. Look at the state of the environment and agriculture system in China today to see the evidence.