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Dirt: The Erosion of Civilizations

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Dirt, soil, call it what you want?it's everywhere we go. It is the root of our existence, supporting our feet, our farms, our cities. This fascinating yet disquieting book finds, however, that we are running out of dirt, and it's no laughing matter. An engaging natural and cultural history of soil ...

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First published May 14, 2007

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About the author

David R. Montgomery

13 books150 followers
David R. Montgomery is a MacArthur Fellow and professor of geomorphology at the University of Washington. He is an internationally recognized geologist who studies landscape evolution and the effects of geological processes on ecological systems and human societies. An author of award-winning popular-science books, he has been featured in documentary films, network and cable news, and on a wide variety of TV and radio programs, including NOVA, PBS NewsHour, Fox and Friends, and All Things Considered. When not writing or doing geology, he plays guitar and piano in the band Big Dirt. He lives in Seattle, with his wife Anne Biklé and their black lab guide-dog dropout Loki.

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Displaying 1 - 30 of 191 reviews
Profile Image for Colby Moorberg.
Author 2 books7 followers
November 9, 2018
I will preface this review by saying that I am an assistant professor of soil science in a department of agronomy at a land grant institution in the US, and happen to teach several classes on soil science and soil conservation. I am also a certified professional soil scientist.

I loved the first two thirds of the book. The summaries of the history of erosion and civilization were both interesting, and accurate to the best of my knowledge. I greatly enjoyed it. However, from that point on, Montgomery delves into problems with erosion in modern agriculture from the industrial revolution forward. It is during this segment of the book that Montgomery begins to do a lot of "hand waving", and basically gives a "fan boy" like thumbs up to the organic movement while thumbing his nose by just about every non-organic farmer. There are many very concerning aspects of organic farming, in terms of soil erosion, that were not covered - such as the need for in-season cultivation as a common method of controlling weeds, or the greater number of machinery passes through fields required for organic ag - leading to more soil compaction and thus more erosion. Increased soil organic matter alone cannot compensate for soil loss due to these practices. Also, the author blames pesticides on the loss of soil microbial diversity, but conveniently does not acknowledge the fact that pesticides are still used in organic ag... but only from an approved list of outdated chemicals that are no better or worse than those used by modern agriculture today. I have no problem with organic farmers or their methods. I support research into organic methods because I see great potential for the development of new organic practices that can 1) help improve the soils of organic farms and help the farmer's bottom line, and 2) be adapted into modern farming practices. The debate between so-called "traditional" farming and "organic farming" is far more nuanced than Montgomery admits - at least for when it comes to soil erosion. When it comes down to it, if a "modern farmer" sees that there is potential to improve their soil, save them costs, and improve their yields, then they will try it. However those practices need to be proven first.

Montgomery did support no-till, conservation tillage, and cover crops; which I expected and was very happy to see. However, he presents the use of the practices in such a way that the reader could assume that these are not used by farmers using modern agricultural practices. This seemed intentionally misleading, and conveniently fit the seemingly pro-organic narrative of the final 1/3 of the book. In Kansas, for example, over 66% of the farmland in the state is under conservation tillage or no-tillage practices, and cover crop use is on the rise... and that's just one of the many "bread basket" Midwestern states!

Lastly, the way Montgomery presented the use of GMOs is both misleading, and just plain wrong. He writes of the technology as if it is a time-bomb of ecological disaster waiting to happen. This fear-mongering approach is both wrong and unproductive. GMOs are highly regulated, not by just the US government, but by 30+ other governments across the globe. The use of genetic modification is one tool in a very large tool box containing a wide variety of tools being used to help our growing population adapt to climate change - particularly in areas with high risk of drought, saline and/or sodic soils, or even in areas that were eroded due to prior mismanagement. Taking away that tool is not a wise thing to do with a growing population and predictably less water availability. He also conveniently omits the description of other plant breading techniques out there that are USDA organic approved, such as mutagenesis - a far less regulated method that, to me, seems to have the potential for far worse ecological outcomes. It's "organic" though! I do hope that the readers of this book are educated enough to not form their opinions on genetic modification based on the views from a geologist, but instead seek out actual experts in that field of research who are more able to provide them with accurate and informed information.

In summary, I would recommend reading the first seven chapters. After that, just put the book back on the shelf and forget about it. That said, I thank Dr. Montgomery for his fantastic summary of the history of erosion and it's impact on civilizations, and for the effort he made towards bringing attention to this important issue.
Profile Image for Adam.
996 reviews195 followers
December 19, 2010
I've been interested in history, ancient and modern, since my early childhood. Back then, that meant cool armor, swordfights, and dogfighting jet fighters. Now, it's more to do with deforestation and climate cycles. In either case however, and in a host of other realms besides, at some point I grew to notice a conspicuous omission in the narratives: no one seemed to be appropriately concerned with the material facts that drove historical changes. Too much was attributed to forces I had a hard time believing responsible for such momentous changes, like moral decadence and poor leadership, and too little to serious factors that I would now think of in the context of human ecology.

As I grew older, I became concerned with the environmental collapse being inflicted by our civilization. I learned of various Very Bad Things like pollution and climate change and ocean acidification and the depletion of ocean fisheries and deforestation and our very own modern Extinction Event. Eventually, my conception broadened to include the environmental mismanagements perpetrated by early humans: the extinctions of macrofauna in Australia and the New World. What has been conspicuously (and rather inexcusably, as we'll see) missing from both of my explorations has been the subject of this book: the mismanagement of agroecology, and, in particular the twin dangers of soil erosion and siltation.
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David Montgomery follows in the footsteps of Soil Conservation Service writers Vernon Gill Carter and Tom Dale. Their 1970's book Topsoil and Civilization was mentioned in Shumacher's Small is Beautiful, and was my introduction to the topic. They do a perfectly good job summarizing the effect soil management has played in the course of Western history, as well as warning of the dangers facing our new globalized meta-civilization. Those dangers are quite severe, and quite underrepresented in even the most sensationalist or well-informed treatises of the environmental-movement. Our civilization might just survive in the face of all the looming specters in our path, of which Peak Oil and Global Warming are but the most oft-discussed. The one factor that seems to almost guarantee collapse is the same mistake that sealed the fates of Mesopotamia, the Roman Empire, the Maya, Easter Island, and a whole litany of others whose ruins now haunt the public and mystify clueless scholars on the History Channel.

The historical record provides a fairly generalizable pattern for the rise and fall of agricultural civilizations. Populations and cultures bloom in the pantry of early cultivation of fertile land. Then, each time a drought occurs and hard times set in, the hungry populace seeks more and more land to cultivate. This pattern continues: growth in good times and expansion in hard times. Finally, the civilization pushes to its geographical limits. Then, in hard times, farmers must turn to land that is far less suitable for agriculture: hilly land that erodes quickly, or forests with poor soils. When all available land, even the most marginal, is being plowed and loses its fertility to erosion, the large population the civilization had sustained begins to experience serious social pains, as natural mechanisms of population reduction kick in: famine, disease, and war. Sometimes, this collapse is severe enough to make people resort to cannibalism. When the collapse occurs, it is generally quite swift.

We are currently enacting this same frightening mistake on a global scale. The amount of land currently being cultivated is estimated to equal the acreage already lost to degradation. Grain belts in the US, Russia, and China have lost considerable amounts of their topsoil. Iowa has lost half its topsoil in the past 150 years. Losses in soil fertility have been made up for with chemical fertilizers, but per acre production cannot be expected to increase and will likely decline soon, as irreplaceable topsoil is lost. There is still enough food for everyone currently living. This will not be the case soon, as arable land is lost to erosion, degradation, and most of all to urbanization. Then the inequal distribution of food now will become much more dire. In response, the poorest of us will be forced to work even more marginal land and work it even harder (the tropical rainforests are the one remaining supply of untapped arable land). Things will not be good then.

Montgomery presents a bevy of great information and great stories. He begins with an introduction to soil physics, chemistry, and ecology. I wish he'd spent a bit more time on this, of course, but it was much better than either of the other two books I've read on the subject so far (Topsoil and Civilization and Daniel Hillel's Out of the Earth). He spends only a chapter succintly reviewing what Dale and Carter did in Topsoil, without leaving out anything important and adding in besides a number of interseting levels to the stories told. I found his analysis of the role soil erosion has played in US history quite fascinating (it was the true cause of the Westward expansion and, indirectly, the Civil War). He also reviews the history of fertilizers and their organic alternatives. Finally, much of the second half of the book is spent quite poignantly reviewing the situation I shoddily described above. That is, the dire peril soil erosion presents to our civilization. He is not overtly pessissimistic about things, as I am, for whatever reason. It seems that the evidence he and others presents says that, once a civilization has reached the overshoot we have now, the desperation of overpopulation finishes off the job despite any level of environmental consciousness and political response mustered at that stage. And I for one am certainly not impressed with the environmental consciousness and political response we have right now. It's quite late already, and there is still no evidence that things will or can change in time.
238 reviews10 followers
April 3, 2010
If you read one book about dirt this year, make it this one!!!

A more accurate, but perhaps less striking, title for this book would have been "Erosion: A History of Agriculture". It talks about how agriculture started and changed over time, in turn affecting and being changed by politics and the civilizations with which it has been intertwined.

It starts off with a scientific description of what soil is made of, how it is created and lost. The book next talks about a early history of agriculture, then moves to the US and the dustbowl, and finally the book talks about food production in the future.

I heard about this book because the oil doomer blogs were talking about it. In some ways, the state of fertile soil is a little bit like peak oil: a valuable natural resource was built up over many times longer than humans have been around; it helps civilization grow; people start placing greater demands on the resource and taking it for granted; finally... well, in both cases we don't know exactly what the ending will be.

This book is highly recommended for anyone interested in how natural resource have been used, and how they shape our lives.
Profile Image for Ron Khare.
31 reviews1 follower
November 28, 2012
There are three books I've read in the past year that have changed my life: Endgame (Derek Jensen), The Vegetarian Myth (Lierre Keith), and now Dirt: The Erosion of Civilizations.

Simply put, this book shows the mechanisms behind the philosophies of the other two. While never delving much into value judgments, and light on alternatives, this book's main strength is the clear, scientifically sound history of humans, agriculture, and environmental degradation. It ends with a powerful message - that for all our "progress" the modern, global reach of humanity can still barely feed itself, living harvest-to-harvest, and universally losing soil at a rate that, if left unchecked, will end this global civilization within a century or two - jut as assuredly as the same processes have ended so many others over time.

Required reading.
Profile Image for J.S..
Author 1 book48 followers
January 22, 2019
"Historians blame many culprits for the demise of once flourishing cultures: disease, deforestation, and climate change to name a few... Time and again, social and political conflicts undermined societies once there were more people to feed than the land could support. The history of dirt suggests that how people treat their soil can impose a life span on civilizations." (pg 3)

Add "soil abuse" to your list of societal ills that threaten civilization. David R. Montgomery has written a fascinating history of civilizations that have destroyed the soil they used to produce their food. From the ancient societies of the Middle East to Europe to South America to the American South and Midwest to islands in the South Pacific... it's a sobering history. It's also very detailed and comprehensive, and reminds me of more well-known books like Guns, Germs, and Steel and 1491 in how thoroughly it treats lengthy periods of history.

Soil is often seen erroneously as a commodity that cannot be used up. The problem is that the surface layer where food is able to grow takes a very long time to produce from weathering of rock below. When forest cover is removed and the ground is plowed, the soil is exposed to the elements and subject to erosion. When it is over-farmed for quick return "cash crops" and the nutrients are depleted, it no longer produces food. In the past, those societies either moved on to other farmable lands or died out. But occasionally societies developed methods of replenishing the nutrients and were able to last for 1,000 years or more on the same land.

This book has the feel of a textbook, but is still very readable and understandable rather than feeling dense. It's not for the home gardener who wishes to better care for the home soil, but rather a warning to societies and governments that there's a limit to our dirt.

"The underlying problem is confoundingly simple: agricultural methods that lose soil faster than it is replaced destroy societies." (pg 241-2)
Profile Image for Richard Reese.
Author 3 books151 followers
March 23, 2015
Professor David Montgomery’s book Dirt provides a fascinating discussion about an extremely precious substance that we can’t live without, but treat like dirt. He begins with an intimate explanation of what dirt is, how it’s formed, and how it’s destroyed — in plain, simple English.

Then, he proceeds to lead us on an around-the-world tour, spanning many centuries, to examine the various methods that societies have devised for mining their soils, and diminishing their future via agriculture.

The book is impressively thorough, and it’s likely to blow more than a few minds, but the voice is a bit soft. A neutral tone is mandatory for textbooks, and this may encourage casual readers to be less concerned about the future than they should be. Connect the dots.

From a human perspective, soil is a non-renewable resource, because new soil is created very slowly, a process often measured on a geological timeframe. For example, the soils of the Mediterranean basin were largely destroyed by 2,000 years ago, and they remain wrecked today. They are quite likely to remain wrecked for many, many thousands of years. Much of the region that once fed millions is a desert today.

If smoking a single pack of cigarettes reliably caused a painful death by cancer within weeks, nobody would smoke, because it’s clearly not smart. But cancer normally takes decades to become apparent, and by the time you learn about the tumor, it’s too late to make smart decisions. Life does not have an undo button.

It’s a similar story with societies that take up the dirty habit of agriculture, which is almost always fatal. Once you get started, it’s nearly impossible to quit, because it’s unbelievably addictive. Yet we continue to act like it’s a cool thing to do, because it’s a clever way to acquire trade trinkets and status, and all the other cool societies are doing it, too. The disease often advances so slowly, over the course of generations, that nobody realizes the mistake. But once the soil is ruined, it’s too late to become smart. There is no wonder cure. Game over.

Eventually, Montgomery’s world tour brings us to the United States, where the white invaders imported their dirty habit. In Europe, many farmers were quite careful to do what they could to slow erosion, and improve fertility, using time-proven techniques, because starvation was the alternative. American settlers promptly threw these prudent practices overboard, because they were time-consuming, and because there was an unbelievable supply of fertile soil that was readily available. In the New World, dirt was a disposable commodity.

Settlers could get rich quick by raising tobacco and cotton. A field of rich virgin soil could support three or four crops of tobacco, and then it would be abandoned. It was cheaper to pack up, move on, and clear new fields than it was to manure the fields they had already cleared. This careless attitude fueled an explosion of erosion and deforestation. One gully near Macon, Georgia was 50 feet deep, 200 feet across, and 300 yards long. Soil exhaustion was a primary driving force behind the westward expansion of the colonists. Rape and run agriculture seems to have set the mold for the emerging American mindset.

In the twentieth century, when farmers bought millions of big, powerful machines, the 10,000 year war on soils mutated into a new and horrifying form. Erosion rates skyrocketed to levels never before believed to be possible, leading to catastrophes like the Dust Bowl. Montgomery says it like this: “Continued for generations, till-based agriculture will strip soil right off the land as it did in ancient Europe and the Middle East. With current agricultural technology though, we can do it a lot faster.”

Here’s a line that made me jump: “Everything else — culture, art, and science — depends upon adequate agricultural production.” Like air and water, food is essential for our survival. Without food, our entire techno-wonderland turns into fairy dust and blows away. We can’t live without it, but at the same time we are rapidly destroying what makes food possible — because profits today are more important than existence tomorrow. Sorry kids!

On a bright note, Montgomery gives us a quick tour of Tikopia, a society on a tiny island that is one of the few exceptions to the rule. They seem to have devised a sustainable form of agriculture that majors in agroforestry (food-producing trees). They combined this with a draconian method for maintaining a sustainable population, which was far less painful and destabilizing than the effects of over breeding.

Looking toward the future, Montgomery foresees a large number of serious problems. Explosive population growth continues. We are moving beyond the era of cheap and abundant energy, and this will continuously drive the price of everything upward. Climate change is likely to deliver unwanted surprises. Widespread destruction of soils continues, and simply converting to organic farming will not fix this. Nor will no-till technology, which will eventually be forced into extinction by rising energy costs, or herbicide-resistant weeds. We are running out of tricks for increasing productivity. The end of the chemical fertilizer game is inevitable, and it will largely be replaced with recycled sewage — a priceless treasure that we are now throwing away via expensive, energy-guzzling treatment plants.

Our current system is simply not up to the task of feeding the world in the coming decades, because it’s a design that self-destructs. We try to force the ecosystem to adapt to our food production technology, and this doesn’t work. Instead, we need to make farming adapt to the needs of the ecosystem. In short, we need a serious revolution in the way we do agriculture — a new philosophy that gives top priority to the health of the land, not to maximizing income by any means necessary. How likely is this? Don’t hold your breath.

The subject of this book centers on soil erosion. In the good old days of muscle-powered organic agriculture, soil destruction took a thousand years to ruin a civilization, on average. Industrial agriculture is much quicker. It now keeps seven billion people alive by using soil to convert fossil energy into food. But the clock is running out on cheap energy, and industrial agriculture has an expiration date. This will give birth to a new agricultural revolution — the return to muscle-powered farming, on severely depleted soils, fertilized once again by nutrient-rich sewage. Farm productivity will plummet. We are close to peak food production now.

Profile Image for Ann Alice.
35 reviews1 follower
August 19, 2022
Kunagi oma õpetaja esimesel tööaastal pidin 6.klassile andma loodusõpetuses mitu tundi mullast. Sel hetkel mõtlesin, et no kas on igavamat teemat kui muld. Ja nüüd lugesin terve raamatu mullast ja olen täiesti pahviks löödud. Täielik linnalapse tunne oli seda raamatut lugedes... Kuna autor on geoloog, mitte ajaloolane, siis vahepeal loob julgeid seoseid ajaloosündmuste ja mulla vahel, mis võib mõnele vastukarva olla.

Lihtsalt trobikond mõtteid suvalises järjekorras:
->Imestan üldse, et meil Maal veel üldse mulda olemas on, sest see kuidas seda aegade algusest hävitatakse on hirmuäratav.
-> See kuidas inimkond (erinevatel aegadel ja erinevates kohtades) ikka ja jälle samasse ämbrisse astuvad on väga masendav.
-> Enne saab viljakas muld otsa kui nafta.
-> Head põllumehed on nagu head õpetajad - neid on vähe, nad teevad tänamatut tööd ja ühiskonnas võiks nad rohkem au sees olla.

Also: Mets on vist lahendus kõigile inimkonna probleemidele!
Profile Image for Aeryn.
279 reviews
May 29, 2021
Who knew dirt could be so interesting!
Profile Image for Ryan.
962 reviews
August 8, 2020
We don't think about soil enough. In Dirt: The Erosion of Civilizations, David R. Montgomery suggests that soil quality is one of several factors that can contribute to the rise and decline of civilizations. Published in 2007, Montgomery's analysis recalls Jared Diamond's Collapse (2005), but it is about dirt.

We mostly rob soil of its nutrients, turning it into dirt. And we further till it until it just blows or drains away--the erosion that is alluded to in the title. It is not always this way, however. On the Amazon:
Found on low hills overlooking rivers, terra preta is full of broken ceramics and organic debris with a high charcoal content and evidence of concentrated nutrient recycling from excrement, organic waste, fish, and animal bones. Abundant burial urns suggest that the human population recycled itself too. The oldest deposits are two thousand years old.
Terra preta appears to be designed nutrient-rich soil. I can't help thinking of Louv's nature-deficit theory, but maybe we should say we have a nature-detachment disorder. Rather than being hidden into Morton's "away," the imaginary expanse where unwanted things go, human waste and remains become part of the soil people use to feed themselves and to build their society.

Reading Montgomery's analysis of soil use and soil degradation should give people pause. He writes: "because we are already farming about as much of the planet as can be done sustainably, the potential for global warming to affect agricultural systems is alarming." In the 2000s, much of this worry was due to increased temperatures which draw moisture from the soil more quickly as well as a reliance on fossil fuels to continue providing synthetic inputs into the soil. Although oil engineers have continued to amazingly find ways to extract oil from the ground (see Smil's 2008 work, Oil), it is worrying to be so dependent. And although genetically modified wheat has allowed my farming family to so far beat droughts, they have recently had very wet harvests that make it all but impossible to get the crop off the ground. Our increased population with its increased appetite adds further strain to the system. My sense is that we are confident to the point of arrogance about our agricultural system.

Unfortunately, I'm not sure what will be done. It would be useful for agriculture to adopt some longterm thinking, but that's easier said than done. If grain prices rise, farmers are incentivized to take short term profits. If grain prices fall, farmers are incentivized to take short term profits. It would be easy to say this is the market running amok, but government policies have also made this the only way for the industry to work. I found Michael Pollan's summary of this predicament in The Omnivore's Dilemma (2006) more engaging than Montgomery's.

Montgomery generally likes agroecology, urban farming, and he's enthusiastic about organic farming methods as well. He outlines what happened to Cuba when the Soviet Union was no longer able to provide them with synthetic inputs. Although their system is hardly ideal, Montgomery notes that people are not starving. Are these real plans or is this any port in a storm thinking? I will read more on dirt (however reluctantly--it's not especially interesting to me), as I can't help feeling we can do better.

Update 2020: I read Gabe Brown's Dirt to Soil and recommend it. It's a bit more upbeat, too.
918 reviews
February 1, 2015
I don't read that much non-fiction. I read this on the recommendation of one of the farmers from whom we get vegetables in the summer. It's really quite fascinating. There are really two levels on which I really enjoyed it. First, there are lots of those little facts that just seem interesting and often counter-intuitive. (The subject of Charles Darwin's last work? Earthworms, on which he did really extensive research.) Second, there's the big pictures. Over and over again civilizations have exhausted their land--through erosion or over-farming. And virtually every time this leads to instability and a range of other consequences which often form part of the explanation for the fall of the civilization. Seeing the pattern is no guarantee of escaping it.

I think the author must say this early on--we just don't think about dirt all that much. But he makes a really compelling case that we ought to.
Profile Image for Jaimee.
44 reviews2 followers
June 27, 2010
I'm a soil scientist and my soil scientist friends highly recommended this book. The concepts behind this book are very important and I wanted to love this book. However, it was extremely repetitive! It took me forever to read it because it just seem to drag on and on. If you want to read a book about this subject: how we have have mistreated our land, created severe erosion problems and destroyed our topsoil--read The Worst Hard Time: The Untold Story of Those Who Survived the Great American Dust Bowl by Timothy Egan.
Profile Image for Natasha.
175 reviews31 followers
February 1, 2016
This book was a recommended read in honor of the International Year of Soils (2015). It shows how important the soil is to the rise and fall of civilizations. We tend to take dirt for granted, but it is critically important. I like how this book raised my consciousness of this fact.

My dad was a soil scientist. I regret I was not able to discuss this book with him.

This is a link to the first few pages of the book: http://content.ucpress.edu/pages/1059...

I read the audio version and felt it was well done.
Profile Image for Patty.
738 reviews11 followers
August 23, 2011
I just could not get into this one and skimmed most of it. The idea is interesting--how geography and our use of the land contributed to the rise and fall of civilizations over time--but the execution is quite dry and not as engaging as I would have hoped.
Profile Image for Lindsey.
48 reviews1 follower
April 13, 2009
I selected Dirt: The Erosion of Civilizations because I am very interested in sustainable agriculture and the interplay between culture and ecology. Reading Dirt offered me the opportunity to explore the history of agriculture and how different societies interacted with soil, one of our most basic and sustaining elements of nature.

“Soil is our most underappreciated, least valued and yet essential natural resource.” (3) Soil plays a fundamental role in the history of civilization. Dirt’s main premise is how agricultural methods that lose soil faster than it is replaced destroy societies. Montgomery carefully illustrates this truth by explaining how various cultures slowly destroyed the earth that sustained them. He details the history of our agricultural beginnings and recounts a cycle of agricultural production, increased population due to greater food availability, soil degradation and erosion caused by feeding a growing population, and eventual land abandonment or starvation, common throughout history.

Dirt helps to elevate our understanding of the elemental importance of soil to societies throughout time, with ramifications for the modern day. Good stewardship and conservation will be an imperative, and technology will not ultimately rescue us from unsustainable agriculture practices.

The chapter entitled “Skin of the Earth” is an excellent primer on soil, which Montgomery describes as “the frontier between geology and biology,” as a balance between mineral and biological elements. He introduces UC Berkeley professor Hans Jenny’s five key factors governing soil formation: parent materials (rocks), climate, organisms, topography, and time. Montgomery also explains how topsoil and subsoil systems impact erosion rates and how differences in geology and climate dictate agricultural sustainability. The concept of isostasy whereby new rocks rise to the surface to replace eroded soil was particularly fascinating.

Montgomery also relates a little known fact that Charles Darwin’s last book, published a year before he died, was about the role of earthworms in soil. Darwin’s account helps to explain the dynamism of how rocks, biology and decay produce soil. The author briefly singles out hilltop farming as posing soil conservation challenges and also introduces soil erosion prevention practices, like terracing, no-till farming, using crop residue as protective mulch and intercropping. The reader can easily refer to this scientific background information to help heighten and synthesize an understanding of the complex causes of civilization collapse detailed later in the book.

Civilization naturally began in fertile river valley regions, where hydrological and geological characteristics provided abundant agriculture potential. The chapter “Rivers of Life” chronicles agricultural innovation and cultural development in the Middle East. Some experts contend that climate change required people to cultivate plants to survive the warmer environment, while others explain agriculture as an inevitable cultural evolution irrespective of environmental factors. Montgomery gives the historical record a factual account, refusing to grant allegiance to the oasis or the cultural evolution hypotheses for the origins of farming, and instead concludes it is a likely combination of the two. Early agriculture fostered the development of political, religious and economic institutions to support the cultivation and distribution of food supplies and the rise of civilizations like Sumer and Egypt. Economics, in particular, is at the crux of the issue of soil conservation management, as we will learn many times throughout Dirt.

The author’s introduction of soil science concepts and the early beginnings of agriculture was excellent and left me wanting to learn even more, which is perhaps why I found the subsequent case studies of Rome and Greece in chapter four “Graveyard of Empires” a bit tedious. I found Montgomery’s exploration of ancient Greek and Roman agriculture long-winded and despite a good introduction to soil science concepts, some of the terminology was difficult. It seems as if he is trying to accommodate a long list of dates and facts rather than amplifying some important concepts with scientific findings. Maybe there was a lot of relevant ground to cover and he wanted to maintain a level of detail. Perhaps if these chapters were more clearly organized with subheadings for statistics and details about different eras and regions the information would not have felt so overwhelming. It could be more manageable if some of information could be condensed and represented with graphics that could be more clearly presented to the reader.

Despite the overwhelming details, “Graveyard of Empires” introduces some key concepts. Montgomery dispels the Pristine Myth by stating unequivocally that early societies did not live in harmony with the land and few societies manage to conserve their soil. Modern problems with tenant farming, owners being divorced from the land and large land consolidation is first recorded in ancient Rome. The plow, the quintessential symbol of farming, was introduced in Rome and is specifically singled out as causing soil erosion to exceed soil production.

In Let Them Eat Colonies Montgomery describes how agricultural degradation and industrialization lead to colonization in order to satisfy Europe’s large hungry population. Montgomery’s political exploration of the link between hunger and revolution in Europe help readers to connect to issues of soil mismanagement and agricultural economics to history as well as the philosophies of Thomas Malthus, Adam Smith and the modern Cornucopian concept of limitless technological expansion. These ideas provide the reader with much food for thought and could be expanded into another book entirely.

Westward Hoe expands soil erosion linked to economics even further. In the colonies of early America, particularly Virginia, cash crop production, like tobacco, was dictated solely by the economics. As in early Rome, farmers did not own the land and therefore we not invested in long-term soil health. Degradation occurred quickly and farmers were moved westward in constant search of new cheap land.

Chapter 7, Dust Blow, uses shocking statistics to describe the Dust Bowl experience in America in the 1930s. The rise of the tractor highlights the uniform approach of farm mechanization, which was very similar to slave plantation crop production methods. He draws similarities between corporate farming and land management in the South and early Rome, in which corporations, as landowners, cause land tenure instability, fostering erosion. He critiques the economic drivers and environmental consequences of industrial agriculture and dispels the myth that large farms are more efficient than smaller traditional farms, citing that smaller farms require less artificial inputs and are able to produce more food on the same amount of land. This was a compelling issue that could have been developed further to expand on economic drivers, a major undercurrent running throughout the book.

Dirty Business provides a much-needed history on modern conventional food production, in which wartime production capacity was converted easily to fertilizer production. An account of South American guano mining is particularly interesting when comparing the limited guano fertilizer supply to natural gas-based fertilizers in light of peak oil concerns.

Islands in Time concludes by proposing that our planet itself is like an island and we are very near to a time where we will be unable to find new sources of healthy farmland. The story of Easter Island, a favorite fable of conservationists appears, and is compared to sustainable soil efforts of other island peoples like the Tikopians.

In the concluding chapter, Life Span of Civilizations, Montgomery elegantly returns back to the premise of the book of how soil erosion destroys societies. In opening the book he originally explained how this story is “out there in the dirt.” To this, the author literally dug out the evidence and married scientific facts to cultural histories to describe their collapse. These are lessons for today and we cannot afford to lose more soil. Montgomery cautions us that our survival depends on treating the soil like a valuable inheritance and investment, not as a commodity or, derisively, simply as dirt.

Montgomery is a geomorphologist (a scientist who studies landforms) and this book, at times, seems geared to scientists who want to learn more about historical context of their subject of study, rather than for the general population and those with a background in the humanities. Dirt could easily be better tailored to a general audience by condensing and reorganizing some of the historical details and simplifying the terminology. The chapters themselves are nicely organized and guide the reader sequentially and chronologically through concepts and histories. Montgomery purposely considered how the reader would move through the stories and the book as a whole flows well. For example, the book moves from Europe to the New World colonies to the Dust Bowl in later years. However, within chapters he switches back and forth between cultures and histories without notice or delineation. Subheadings within chapters could easily remedy this issue.

Despite Montgomery’s at times disjointed writing style, the book offers well connected evidence drawing on and pulling together diverse histories, and includes a number of classical scientific leaders like George Perkins Marsh and Charles Darwin who readers will connect to. I am not aware of similar titles that chronicle the important role of soil in the rise and decline of civilizations. Dirt appears to be a unique contribution in fusing science and history to sustainability and culture. Readers who enjoyed Jared Diamond’s Collapse, and are interested in agricultural issues will undoubtedly like Dirt as well.

I enjoyed Dirt: the Erosion of Civilizations because it was an entertaining read that added another important layer to how agriculture shapes history and will shape the future. Montgomery elegantly weaved together a fascinating tale of culture, history, economics and politics driven by soil health. Dirt offers a new perspective in which to frame agriculture, urging readers to consider a philosophy for a new agriculture - agroecology - that views soil as a locally adapted biological system based on biology and ecology instead of chemical system rooted in chemistry and genetics. Agroecology transcends common notions of sustainable agriculture as organic and/or small farms and instead urges productive farming that adapts to the land without trading in soil fertility for short-term profits. This new and well-integrated framework urgently calls for reform and should be a “must-read” for students of agriculture and policymakers who work with agriculture and food issues.
Profile Image for Thomas Elpel.
37 reviews4 followers
December 27, 2017
Are humans capable of learning from past mistakes? I consider myself more soil literate than most people, enough to recognize the process of desertification on the ground. I’ve long read about the rise and fall of civilizations based on the health of their soils. However, David Montgomery’s Dirt: The Erosion of Civilizations provided a deeper, more riveting account of the repeated rise and fall, rise and fall, rise and fall of civilizations due to failure to learn from the past.
Walking the reader through a history of agriculture throughout the world, Montgomery introduces different soil types and climate issues, as well as the social-political circumstances that contributed toward erosion and collapse of past civilizations. While some regions lost their soil and permanently collapsed, others recovered enough to allow the same mistakes to play out again and again.
In general, agriculture and urban centers arose, cultivating the most favorable, typically level plots. Food production enabled a bigger population, which then added pressure to deforest and plow hilly uplands, resulting in a surge of erosion. Sometimes too slowly to perceive in human terms, erosion deteriorated the uplands and often buried the lowlands. Crop harvests crashed, and people either starved or migrated elsewhere, leading to collapse of civilization after a few centuries. The land was abandoned. Nature began to form new soil from bedrock, and many centuries later, people returned to make the same mistakes all over again.
Not only did the boom and bust cycle repeat, but keen observers such as Aristotle and Plato diagnosed the problem and witnessed the remains of past civilizations, yet, they too were unable to change the outcome.
It is easy to imagine some future soil sleuth will write a book about the collapse of the American empire due to soil loss. Maybe they will even find an old, tattered copy of Dirt: The Erosion of Civilization, and they will see that David Montgomery, like Aristotle and Plato, strived to call attention to the health of the soil.
Better yet, let’s all read Montgomery’s book now and increase our soil awareness to avoid becoming trapped in the cycle of doom.
Profile Image for Jon Cimuchowski.
4 reviews1 follower
October 6, 2009
cross-posted with links at
http://gettingbetterallthetime.wordpr...

Dirt, the Erosion of Civilization, by UW professor and 2008 MacArthur Foundation Fellow David R. Montgomery is a wonderful read. I highly recommend it.

Previously, I thought, “dirt, who cares”. I should have known better, I’ld seen a beautiful photo essay in Scientific American (August 1996, pg 62-67) showing the amazing diversity of grains of sand. I should have known that soil has different levels of fertility, or not, as may be the case with my lawn.

Montgomery is a good author, and evidently noted geologist. It was an enjoyable read, and I think would make a decent companion book to Jarred Diamond’s Collapse (my review here). Montgomery believes that a civilization is only as good as the soil on which it grows its crops, and previous civilizations would fall apart when the soil fertility dropped.

He starts with Darwin’s worms. Darwin’s last work, how worms create dirt.

He talks a lot about sediment core samples, and also the faults of land laws that lead to soil depletion.

Before this book, the libertarian side of me would wondered by what right does the government have to encourage land management. The Dust Bowl provides a good reason. Even if you practice good soil management techniques, if your neighbor doesn’t and his dirt gets blown away and in the process buries your crops, then your property has been damaged by his actions. Take at this USDA photo from Dallas, South Dakota, 13 May, 1936.

Dallas_South_Dakota_1936A Congressional report from 1936 identified the problem, “When the price [of wheat:] collapsed during the post-war period Great Plains farmers continued to plant large wheat acreages in a desperate endeavor to get money with which to pay debt….they were obliged to extend farming practices which were collectively ruinous.” (pg154-155). Many times I’ve seen that come up, crop prices fall, so farmers grow more food to make more money, causing crop prices to fall.

More from the “we knew this long ago file”, Sir Albert Howard, in the 1930s was preaching the virtues of composting (pg 202).

Another problem, is absentee landlord. If you have a short term lease on the land, especially at high rent, you want to make profit quickly, and don’t care about the future soil value.

We told, a 1989, US National Research Council report, Alternative Agriculture, “Well-managed alternative farming systems nearly always use less synthetic chemical pesticides, fertilizers, and antibiotics per unit of production than conventional farms. Reduced use of these inputs lowers production costs and lessens agriculture’s potential for adverse environmental and health effects without decreasing-and in some cases increasing-per acre crop yields.” (above quote from pg 9) So why huge mono-culture mega farms…because they work best for heavy machinery (pg159). I suspect that the small farm is a lot more labor intensive. See also 1974 study by Washington University’s Barry Commoner (pg 207), or mid-80s research by WSU’s John Reganold. “…many currently profitable conventional farming methods would become uneconomical if their true costs were incorporated into market pricing. Direct financial subsidies, and failure to include costs of depleting soil fertility and exporting pollutants, continue to encourage practices that degrade the land” (pg 209-210). Subsidies such as ~$10 billion a year for wheat, corn, soybeans, rice & cotton. Hmmm…what is the worth of a worm, especially if it makes it so less fertilizer, less subsidy is needed?

I was happy to find, a source for what I claim, the world has enough food, people are starving because of politics. The UN Food and Agriculture Organization “farmers already grow enough to provide 3,500 calories a day to every person on the planet” (pg 200).

One very worrisome example that Montgomery uses, Tikopia. “This tiny island offers a model for sustainable agriculture and an encouraging example of cultural adaptation t limited resources” (pg 223). Montgomery describes their island as a “a giant garden…a system of multistory orchards an fields” (pg 223). Sounds great, an island paradise, what do we need to do, Dave? Easy, the “Tikopians practiced draconian population control based on celibacy, contraception, abortion and infanticide, as well as forced (and almost certainly suicidal) emigration.” (pg 223). Gee, Dave, you ever wonder why a large percentage of people refuse to listen to you? Poor delivery, and probably not even an example that is valid, since you pointed out, we have enough food!

Still…a good book. Don’t worry, the Soviets had their own Dust Bowl, but after USA, so they REALLY should have known better.

Montgomery, for me personally, is the first shot in the “don’t need chemicals to grow food” debate. And, since he’s an actual geologist, I’ll give his voice more credence than “HippyFarm-dot-net”.

Now here’s a crazy question…if, all the good dirt is blown away, or washed away…and eventually ends up in the ocean. Couldn’t we just dredge the ocean for some fertile dirt?

And, 20 page bibliography, cool!
This entire review has been hidden because of spoilers.
Profile Image for Bob Stocker.
189 reviews2 followers
October 26, 2011
This review contains summaries that some people may consider to be “spoilers.”

The story goes something like this. A group of hunter-gatherers discovers agriculture. It plants fertile valleys and settles down. Population grows. Soil becomes depleted. Because this happens over multiple generations, no one notices the change. Eventually, more land on erosion-prone slopes is planted to avoid famine. The sloping land erodes. The society crumbles, relocates, or becomes dependent on imported food. In Dirt: The Erosion of Civilizations David Montgomery tells variations of the story over and over again: Mesopotamia, Greece, Rome, Europe, China, Easter Island, and the American South are but a few of Montgomery's examples.

This is not an exciting book, but it's important. Its message may even be critical to the survival of humanity. Virtually all the land capable of supporting sustained agriculture is already being farmed – though most of it is not being farmed sustainably. Advances of the “green revolution” have slowed. Monoculture is producing short-term income at the expense of long term soil condition. Each year more fertilizer is required to raise the same amount crop. Most farms are losing soil to erosion. To make matters worse, modern agriculture in developed countries is highly dependent on petroleum, which is itself being depleted at an alarming rate. Even without considering the stresses of an exploding human population and a changing climate, global agriculture seems to be headed toward collapse.

Montgomery feels a new agricultural revolution is needed to avoid catastrophe. He suggests changes like rotating crops, planting cover crops in winter, farming without plowing, enhancing soils with organic matter, and modifying agricultural policies that may help bring about the necessary revolution. There is hope. Some farms have already introduced these changes successfully.

It's difficult to apply a star rating to this book. The message is timely and critically important (5 stars). The research is thorough (5 stars). Conclusions are carefully drawn (5 stars, again). The writing is clear (3 or 4 stars), and at times forceful (4 stars), but rarely succinct (2 stars). I ended up giving the book 4 stars even though I rarely “really liked” what the book was telling me.
114 reviews
January 14, 2008
"Cuba's conversion from conventional agriculture to large-scale semi-organic farming demonstrates that such a transformation is possible--in a dictatorship isolated from global market forces. But the results are not entirely enviable; after almost two decades of this inadvertent experiment, meat and milk remain in short supply" (232).
Illustrated in this passage, Dirt at points lacks critical analysis of issues - is a bountiful supply of animal flesh and milk really viable for human societies, which wish not to quickly erode soil? - and is ethnocentric.
Despite weak or inexistent analysis, David Montgomery provides some strong links between collapses of societies and soil loss. Much of the book reads as a sensational piece with little focus on particular "civilizations" but rather on statistics meant to shock the reader. Montgomery throws around hectares, inches, barrels of oil stacked to the moon and back. These statistics actually have very little meaning. A reader may have just as equally been shocked reading the factoid on oil barrels if they stacked to the moon once or 2,100 times instead of the 2,000 times cited in the book. Dirt has a lot of compelling arguments; they are just buried in a pile of crap.
6 reviews
October 26, 2012
I really enjoyed this book. I think David Montgomery does a fantastic job weaving the narrative or history in with the pragmatism of science. He makes a convincing case for environmental determinism in historical societies which faltered (Romans, Greeks, etc.) but stops well short of saying it is the only reason. Once making his case historically, he uses these parables to create a narrative of modern time, mostly America, backed up by a lot of interesting Geological data.
This is a very interesting book, that very rationally lays out its case without sounding alarmist to the point of alienating a subset of its readers. I highly recommend it.
Profile Image for John.
96 reviews1 follower
November 12, 2021
The actual writing and presentation of the book is probably a 4/5, but I'll boost it up for the importance and scope of the subject. Montgomery provides an engaging exploration of the intersection between human societies' intrinsic tradeoffs between short-term vs long-term, local vs global, and our fundamental biological requirement of nourishment, which is intrinsically tied to the availability of fertile soil. The book presents many examples of societies and land practices across history, geography, and scale, although sometimes the way they're presented makes it seem like Montgomery may be brushing some other important factors under the rug in order to better present his personal pet theory. The last ~quarter of the book focuses on modern trends towards sustainable agriculture, but I don't know well enough about this field to comment on the validity of its presentation. All that being said, I think this book is a great and accessible introduction to the field of soil and agricultural science, providing both a history and an immersion into core concepts that will pique the reader's curiosity and provide a foundation that will enable a deeper dive into this field.
Profile Image for Brianna.
72 reviews1 follower
October 15, 2021
This book was really informative about the history of soil health across a wide range of civilizations and I really liked the narrative voice. At some points it did get pretty repetitive and overly simplified, but overall I liked it!
Profile Image for Craig Scharton.
15 reviews
May 14, 2019
I wish that I could somehow get everyone with any decision making ability to read this book. It is perhaps the most singly important subject on our planet.
Profile Image for Emma S..
1 review
August 23, 2022
The best book I’ve read all year! It was written in 2007 but is all the more relevant to our global reality today and tomorrow.
Profile Image for Ann.
17 reviews10 followers
June 29, 2017
This book is not just for soil geeks. This is for anyone interested in world history, looking for a way to wrap their mind around the intertwining forces, personalities, and flukes that have brought us to where we are today. “Dirt” shows how the arc of human activity over the past 10,000 years or so can be understood through the lens of how we have used and managed soil. The evolution of cultures and the rise and fall of civilizations are entwined with changes in the thin skin of the earth that is the source of our food.
For those who haven’t thought about the world beneath our feet, Montgomery starts with an explanation of the significance of soil and how dynamic and irreplaceable it is. He provides a concise explanation of the useful fundamentals of soil science. (In other words, this book is World History 101 and Soil Science 101 wrapped together.)
For the rest of the book, Montgomery examines a few dozen countries and civilizations – ancient to modern – to show how the way they manage their land imposes a life span on civilization, and is tied to the social-political structures of the societies. Stories such as: How Mesopotamian agriculture was destroyed by salinization of soil and silt filling irrigation ditches so that by 1800 B.C. crop yields were 1/3 the initial yields in the region. How the flooding of the lower Nile River, coating the floodplain with silt from the Blue Nile and humus from the White Nile, supported agriculture in the region for 7,000 years until the Aswan High Dam was built in 1964. How the history of Easter Islanders’ ecological suicide is preserved in the island’s soil. Why wars were fought over guano islands. Why slave labor and monocropping were incompatible with soil conservation in the United States. And on and on.
In 1901, Milton Whitney, the newly appointed chief of the USDA Bureau of Soils said “The soil is the one indestructible, immutable asset that the nation possesses. It is the one resource that cannot be exhausted; that cannot be used up.” This static view of soils is dangerously misguided. Soil degradation is locally visible when you are looking for it. But the dramatic changes happen over generations, so it is easy to assume it has “always” been like this. This is why it is important to study how the vigor of virtually every society through history, and across every part of the globe, has been tied to the changes in its soil – to remind us that our collective destiny today is still tied to our soil management.
“Dirt” is jammed pack with fascinating lessons. It will change how you understand this thin skin of the Earth – “like a coating of lichen on a boulder” – that humans are firmly rooted in.
Profile Image for Carolyn.
922 reviews22 followers
February 24, 2012
I read this mostly because the author's parents are friends and college classmates of mine, and they were rightly very proud that he got a MacArthur Genius Grant for his work. I see why - it's an important book and I'm very glad I read it!

He looks at the lifespan and downfall of civilizations in terms of exhaustion of their resources, topsoil in particular. When a society can no longer feed itself, it falls apart, and it's easy to exhaust topsoil, especially in hilly terrain that promotes erosion. It's most apparent in isolated island cultures. Easter Island was settled by Polynesians who devolved into war and cannibalism when the volcanic slopes they farmed washed into the sea. Their descendants have no idea how the huge statues were moved (they were rolled on logs) because they have no concept of trees or logs, so they say the statues walked to their present location. Iceland and Haiti are two other examples of deforested and denuded islands whose history is detailed in this book.

The United States exhausted the seemingly limitless land of its southeast coastal regions by growing tobacco for cash. Tobacco strips land of its nutrients, and instead of replacing them by manuring the land, growing leguminous "green manure" or leaving the land fallow in a cycle, the farmers simply moved west. Tobacco and then cotton were grown with slave labor, and as the author says, "Any parent of teenagers knows that involuntary labor is not very efficient."

Some of our grandparents remember the horrible black windstorms in the Dust Bowl of the Great Depression, caused by homesteading and plowing up the prairies, which had been stable grasslands supporting vast herds of bison for thousands of years. Farm subsidies today continue to support big agribusiness, which depends on oil-based chemical fertilizers and pesticides. We have already lost billions of tons of topsoil and we continue to lose it at rates far greater than nature can replace it. Will oil become too expensive to use on crops, or will we run out of topsoil before we run out of affordable oil? The answer will become apparent during this century. Topsoil loss is a slow process, so the government will likely not address it until it has become a crisis.

It's a long and detailed book that put me to sleep at times; you may want to read the final chapter and then go back to follow the history and arguments leading to the conclusion as far as your interest takes you.
Profile Image for John Breker.
18 reviews1 follower
April 26, 2014
Montgomery uses numerous, worthy accounts of soil erosion and degradation throughout the course of civilized human existence to build a strong case for soil conservation. He includes examples of soil degradation ranging from Ancient Mesopotamia and Mesoamerica to contemporary America. The book tends to become monotonous as each account is just another variation on a theme of soil erosion that has played out countless times. This repetition highlights the effect of soil erosion on our history; however, I became bored, which surprised me considering that I am a soil scientist with a vested interest in the subject. Although Montgomery attempts to craft a story, his writing style did not engage me in any literary or scientific sense.

Montgomery also omits quantitative, scientific evidence in his proposal to address the future of soil management. Even though his endorsement of no-till agriculture to reduce soil erosion is scientifically meritorious, he proposes other agricultural practices that either contradict or ignore the tedious historical lessons that he had described previously; this may be where I find the greatest fault with this book. Here, Montgomery abandons scientific rigor on a truly scientific issue for what likely are ideological reasons. I had much higher hopes for this book that examines a resource I dearly care about.
Profile Image for Connie.
337 reviews15 followers
December 11, 2019
The first thing to make me complain about this book was the formatting. The chapters are SO long with no breaks whatsoever. It really would improve readability if the chapters were chopped up into smaller sections. But that speaks nothing to the content. So…

I found the book very interesting, if a bit tediously repetitive at times. I suppose that happens when one is talking about historical cycles. Of particular interest to me was the effect slave labor had on the soil and agriculture of the southeastern United States. One thing that would have been nice for a layperson such as myself is the addition of some more science. He focuses heavily on the evidence collected from “sediment cores.” While one can glean a few tidbits about it from some of his comments, it would have been nice if he had actually explained the process. Now I’m left with a whole bunch of unanswered questions.

I enjoyed learning about Darwin and his worms. That was fun. And the part on agrochemistry was pretty interesting, too. Of course, learning about alternative farming methods to help build up soil and decrease erosion rates was a big focus of the book. I really like the idea of soil as a biological system. It really makes you look at dirt differently than one normally would and respect this precious resource that we take so for granted.
Profile Image for Nadia.
29 reviews
August 13, 2015
Brilliant book. A must-read, I believe, for all those interested in the history of civilizations, sustainability, agriculture (organic or not) and, last but not least, a philosophical pondering on the human folly. The folly of consuming today the resources of generations to come (something by no means specific to today's people). The folly of behaving as if there is no tomorrow (and by that making tomorrow harder and harder to exist at all). Yet a moderately optimistic book, looking at history and at causes (and potential solutions too) without anger or exasperation, but with the calm eye of the scientist.

Don't be put off by the first chapter, which sets the theoretical foundation of the following chapters (if geology is not your cup of tea, that is); the book is so interesting and so well structured that it reads almost like a thriller, despise being a very serious and well-documented non-fiction book.
Profile Image for Kara.
27 reviews2 followers
July 15, 2017
Giving this book four stars simply because I learned so much about the history of the world, and who knew it would be through the lens of something as basic as DIRT! There are so many social and economic implications wrapped up in soil that it has literally caused the rise and fall of civilizations, over and over, throughout humanity. There are so many such examples that the book was repetitive and somewhat hard to get through in parts. It was all about agriculture and I would've liked to learn more about how other land uses have impacted soil erosion and fertility, such as urbanization and mining. I also question some of the bad rap given to genetic engineering and technology at large (because what are those but tools to be used for good or bad?) but overall this was an illuminating read on a hugely important topic.
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