This review of Dirt: The Erosion of Civilizations, a book by David R. Montgomery, is the second review of three in a series about books focusing on the effect of soil erosion on societal collapse through history.
Reviewed Here: Dirt: The Erosion of Civilizations By David R. Montgomery Published by University of California Press in 2007
Following the publication of Dirt, David Montgomery gave a lecture in which he acknowledged he was not the first to tackle his book's subject matter, and praised the first book I reviewed in this series--Carter and Dale's Topsoil and Civilization. This is true, but with Dirt Montgomery has written a more complete and much more gratifying book exploring the relationship between soil erosion and societal collapse.
I say more complete because Montgomery, a geomorphologist at the University of Washington, begins Dirt from the Geological point of view with an explanation of how the first soils formed and the factors of natural soil formation and erosion. We learn, among other things, that nature has a mechanism--called isostasy--to replace soil and rock erosion with fresh rock from deeper within the earth. And about Darwin's discovery of the monumental role that worms play in soil maintenance. As a farmer I found this section fascinating and an improvement over my somewhat limited understanding of soil dynamics.
Like Dale and Carter in Topsoil, Montgomery provides a thorough description of the evolution and increasingly destructive nature of agriculture through history, and the devastating consequences of soil erosion experienced by the vast majority of civilizations past. But whereas Dale and Carter had little to say about our present world-wide civilization, Montgomery spends much of his book focusing on the progression and problems of modern agriculture.
This is the best part of an excellent read. Beginning with American colonial agriculture Montgomery brings us up to the present day, covering in respectable detail the major technological and philosophical developments that have increased soil erosion rates to the unprecedented range of 10 to 100 times the natural soil erosion rate.
I suppose I was so happy to read this book because Montgomery supplies a big-picture view that I go long periods without appreciating. Discourses about agricultural crimes are often segregated. Abuse of fertilizers. Biotechnology. Pesticides. Heavy tillage. Oil-fueled farming. With Dirt, Montgomery provides a historical basis for all of them and then connects them to one of humanity's most vital resources: the soil. He then explains that the destruction is not inevitable. It's not that we farm, he says; it's how we farm.
"So far in the agricultural era, nearly a third of the world's potentially farmable land has been lost to erosion, most of it in the past forty years."
Currently, this erosion works out to several tons of soil each year for every person on the planet. A sobering thought.