Dirt: The Erosion of Civilizations

Perhaps the 3 most important challenges to contemporary man are 1)How to reduce dependence on non-renewable fossil and nuclear fuels,through reduced energy needs/person and development of realistic alternative energy sources 2)How to reverse the ever growing medical costs/person , due largely to delayed chronic illnesses and their inappropriate treatment, largely caused by unhealthy diets and lifestyles.3)How to reverse the rampant degredation of agricultural and forest soils that humanity largely depends on for their bodily sustenance and other important products. Of the 3, the last is the most important and by far the least appreciated by the general public, news media and education establishments. Of course, to a substantial extent, these 3 challenges are interrelated.Conventional mechanized and feedlot farming consumes considerably more inanimate energy(as well as agricultural land) than no and low-till agriculture and largely vegetarian diets complemented by grass-fed ruminant products. Spread out, functionally segregated, urban communities necessitates much energy expenditure(animate or inanimate) to get people and materials around, besides often eating up much previous farm land. High consumption of processed and feedlot foods, combined with inadequate exercise, is generally recognized as the greatest threat to the long term health of modern people. Inappropriate plowing of agricultural and marginal land has much reduced its organic matter content, thus much contributing to the ongoing rise in greenhouse gases, which relates to excessive fossil fuel usage. As the author argues and documents, if we wait until food prices double and triple because our topsoil has all been eroded due to short-sighted expediency priorities and perserve government policies, it will be too late to save humanity from an apocalyptic fate that has befallen countless 'advanced' societies in the past several thousand years. Dr. Montgomery provides numerous examples lf soil mismanagement and good management through the ages, and often provides reasons for these differences. He marshals evidence that present agricultural practices that minimize soil erosion and build the organic matter content of soils are not necessarily a short term economic liability for the practitioners. He holds out the possibility that further understanding of how the extinct Amazonians made their unique remarkably resilient and fertile terra preta soils may provide an additional tool for achieving sustainable fertile soils without massive applications of nonrenewable inorganic fertilizers. The contemporary book 'Collapse' covers much the same territory, but is much longer, is broader in scope in some respets, but with generally less depth on the subject of soil itself. The 2 books should be considered largely complementary, and among the most important books for everyone to read and understand. I do wish the author had chosen a better title. In our introductory course in soils, it was quickly made clear that 'dirt' is any rather granular or powdery material that is out of place, according to our interests. This book is about soil management and mismanagement, not dirt!

In less than 250 pages Montgomery does a pretty good job of explaining what soil is, the history of what people thought about it, and the history of how people used (and mostly destroyed) it."It's like the earth's skin" he keeps saying. And as a non-scientist, the analogy is appealing.When he deals with the past, the pattern he lays out is simple: a civilization uses up its soil, and moves on to other soil to use up; or a civilization uses up its soil, and the civilization declines.Problem: we don't have much new soil to move on to, all the best stuff is in the temperate zone (the soil in the tropics is not as good and gets depleted much more quickly), and we don't really want to decline.He makes the case for farming in different ways, smaller farms, less monoculture, drastic reduction in pesticide and fertilizer, more labor intensive farming, mulching/manure, contoured plowing, etc. etc. It is both radical, and reasonable.- - -- -- --- ----- --------- ----- --- -- -- - -Units! Units are the worst part of the book.He's only got four things to measure, but he makes it so hard to follow. We have depth of soil. That one he handles ok. He uses inches, and he uses feet. Reasonable.Time. He uses years. Tens of years. Hundreds of years. Thousands of years. And generations. He should dump those generations. Unnecessarily confusing. But I'm being picky.Areas. Acres. Hectares. Square miles. Size of ________ (fill in the country). This drove me nuts. Pick a small measure (acre or ha.) and stick with it. For larger areas, pick one familiar area, and compare all others against it. I like France. "An area one tenth the area of France" "an area half as large as France" "a bit larger than France" - If France is the wrong unit, pick another. But pick one, and stay with it. Otherwise the reader just gets confused. Most people do not offhand have the ability to compare lots of areas.How fast does soil erode? Montgomery uses inches per century. Or years per inch. Or inches per year. Or inches per thousand years. The concept itself, that soil disappears, is foreign. Shifting units on top of this is confusing for no reason. I should have converted each figure to inches per century. Instead I just got frustrated as I read.- - -- -- --- ----- --------- ----- --- -- -- - -Soil erosion is important. Soil is a resource that is disappearing like oil. We should know more.Montgomery makes this information accessible. He emphasizes the importance, at a level technical enough for the science-interested layman. Aside from the units (just convert to inches per century) it is a relatively easy read.It is worth knowing more about this topic, and Dirt is an excellent intro.

The author missed to point out, that in Brazil circa 80% of the farmers are adopting no Tillage, or zero Tillage on their farms, that's an area of 36,800,000 ha. 33% of the this area is under no tillage at least 20 years. Another point, the most valuable land in Mato Grosso, even in the Amazon Biome, are the ones that are under Agriculture for decades. Actually, farmers are building up the soil Fertility, through the years of farming, since the soil in our region are naturally really poor in nutrients. So using lime stones, fertilizers and good conservationists practices as no tillage, cover crops, or inter crops, corn with grass to improve the organic matter in the soil and recicle the nutrients, farmers instead of depleting the soil, are actually building condition to grow high yield crops. That's why we see a constant increase in yields here in Mato Grosso and elsewhere. Of course, there is plenty to do concerning about no tillage, crop rotation, cover crops and so on, but you have to keep in mind, that Brazilian farmers are not receiving any kind subsidies. Even though, that the farmers are preserving circa 25,6 % of the Brazilian territory in natural forest in their own property, without any kind of help or payment for this service, instead, they are full responsable for any kind of damage, like fire, or even stealing of valuable wood. In that circunstancies, short term decisions are made in order to keep the business running, so that's why cash crops are always favorable instead of the improving the soil health conditions, by using crop rotation or cover crops with species that break soil diseases development as well to avoid the soil compaction.

It was hard for me to believe how a book about soil erosion could be so fascinating. David Montgomery's Dirt: The Erosion of Civilizations provides an historical survey of the role of soil erosion and depletion and the resulting impact on people. He provides a variety of examples from all over the world and from countries both big and small.The first chapter of the book explains soil in great depth, starting with it's various layers, how it is formed, the role of earthworms and how soil becomes depleted.The next chapters then start discussing how mankind caused soil erosion and soil depletion starting with the activities of the very first people who practiced agriculture. The book then discusses soil in early civilizations including Egypt, Mesopotamia, Rome, and China.The next chapters then deal with the role of colonization and slavery contending that agriculture performed by people who are not directly connected to the land will be short-sighted and lead to more soil erosion. He also discusses regions where families had such small parcels of land that they could no longer practice the fallowing needed to restore the soil. As a result, the soil became less and less productive.There are two chapters focused heavily on US agriculture leading up to the dust bowl. Most interesting, and surprising for me, was to learn that people like George Washington and Thomas Jefferson were warning about the depletion of the soil in America. Later, in the 19th century, there were even more warnings about soil erosion and depletion. As part of this discussion, he talks about the very early pioneers of organic farming prior to WW II.One of the cleverest chapters analyzes soil erosion and depletion in islands around the world ranging from Easter Island to Iceland to other Pacific islands as well as to Haiti and Cuba.Reading the book is like drinking from a fire hose with so much interesting information presented in each chapter. Although this made the book exhausting to read, it turned it into a real page-turner.The book is recommended to anyone interested in agriculture, environmental history, prehistory, or World history in general.

Montgomery shows how soil erosion made ancient societies crumble and how it still affects our agricultural systems today. By plowing the soil and exposing bare soil, we lose the topsoil far faster than it forms. Therefore, we should adopt agricultural methods that don't let the soil vulnerable to erosion, such as no-tillage, crop rotations and permanent cover. I really like this book because it gives a different historical perspective and it encouraged me to buy his second book, Growing a Revolution, bringing our soils back to life.

Once you start this book you get thoroughly engrossed in its topic. What I found most striking is how successive civilisations have mistreated their soil over time which was one of the main factors in their eventual demise. Throughout history mankind has got away with mining soil by moving to new land, but even marginal land is no longer available, which is the main reason why it is so important to sustain the soil we have now.Montgomery makes a compelling case for implementing techniques such as regenerative agriculture, no-till, organic, adding any form of organic material for holding existing soil in place and rebuilding topsoil. He gives clear example of civilsations that have collapsed owing to their failures failing to implement these techniques (Easter Island, the Roman Empire being prime exampes), and sends the reader a clear message that our own long-term societal collapse is staring us in the face if we continue with industrial agriculture rather than transitioning towards more sustainable models that put soil health first.

Bom

Un livre superbe qui détaille tout sur les conditions agricoles des civilisations depuis 10000 ans. Vous serez surpris par ce bouquin.