I have the good fortune to have earned the friendship of a geologist. We met a few years ago when we were assigned to co-teach an environmental studies course at University of the Pacific. Lydia contributed the physical science readings, I contributed the social science and humanities readings. I first encountered David R. Montgomery’s work when Lydia assigned chapters from his book Dirt: The Erosion of Civilizations. I read the thing cover to cover, and I found my dirty soulmate in its pages. His work gave form and structure to my sensory impressions of gardening, and inverted my perception – what really matters in the garden is what’s happening under the ground surface, not on top of it. It’s in the soil.

Recently, my geologist friend handed me Montgomery’s latest book: Growing a Revolution: Bringing Our Soil Back to Life. I flipped it open to find it signed to me by Montgomery. Lydia had just come from a geology conference, where she heard Montgomery speak and stood in line to get the book signed. She had brought this prize back for me – one fangirl to another.

In this newer book, Montgomery is just as obsessed with soil as he was in Dirt, but here he writes less like a university professor and more like a university extension agent. The perspective of farmers permeates this book, because Montgomery traveled the world to listen to what they had to say about their soils. The chapters catapult from Kansas to Manitoba to North and South Dakota to Pennsylvania, and then on to Ghana and Costa Rica before bouncing back to Ohio. The warp of these spatial movements is shot through with the weft of time, as Montgomery digs into the work of historical figures, like Sir Albert Howard and Franklin H. King, who were similarly soil-obsessed and manically mobile.

Montgomery lays out his argument in the first chapter: conventional agriculture destroys soil, and continued farming in wrecked soil contributes to global warming. By “conventional” he means, first and foremost, plowing the land (which breaks down soil structure), but this goes hand-in-hand with dependence on fossil fuels – not just to power the plows, but to produce the chemical fertilizers that agriculture has become dependent upon. Through the erosion caused by constant plowing, and because farmers routinely apply more fertilizer than their plants can use, literally most of that chemical fertilizer runs off into waterways (in the American Midwest, this has caused the ever-growing seasonal dead zone in the Gulf of Mexico). By contrast, conservation agriculture values soil health above all else, regenerating soil and thereby helping to mitigate climate change. Climate-deniers aside, the obvious conclusion is that conventional agricultural practices need to be abandoned in favor of conservation agriculture.

The argument is not unique to Montgomery, and I don’t think he intended to break new ground with this book. I think his aim is to make visible farmers who are already practicing conservation agriculture, and the great surprise of the book is to learn just how many farmers have already switched away from conventional practices. In example after example, on three continents, Montgomery proves that protecting soil health comes at no long-term cost to agricultural productivity – quite the contrary, it saves farmers money (they don’t have to buy the pricey genetically modified seed, nor as much fertilizer, herbicide, and pesticide), and it makes their land sustainably productive.

Another surprising finding in this book is that practicing conservation agriculture can rebuild soil “faster than we ever imagined” – on the order of decades, rather then the centuries it takes for natural soil deposition through geological processes. Granted, this may be less surprising to gardeners who dabble in compost and more so to geologists who think of rock weathering as the main mechanism of soil formation. But it is an encouraging discovery, nonetheless.

For Montgomery, this has nothing to do with the choice between agrochemical farming and organic farming. He’s no fan of agribusiness; as he puts it, “it’s those who sell stuff to farmers who are doing really well under the current system,” and he gleefully reports a farmer comparing fertilizer salesmen to drug dealers. He just doesn’t rule out the possibility that a good soil-conserving farmer might occasionally benefit from an application of fertilizer, herbicide, or pesticide when it is really needed. But he also argues that conservation agriculture will make that need occur less often.

There is a caveat to all of this: some farmers who think they are practicing conservation agriculture are getting it wrong, which leads them to think it doesn’t work. There are three components that must always be present, a mantra that Montgomery repeats throughout the book: (1) disturb the soil as little as possible (thus the emphasis on “no-till”); (2) keep the soil covered at all times (by leaving crop residue and/or planting cover crops); and (3) plant a diversity of crops in rotation. Montgomery says that all the published research he examined debunking conservation practices failed to employ all three components. And all the farmers he visited who were practicing all three components were doing great.

Montgomery’s favorite trope for hammering home this point is the side-by-side soil comparison. “To see these changes,” he writes, “all you need is a shovel.” I counted no less than 11 instances in the book where a farmer drives a shovel into the ground on his own land and shows the rich, crumbly soil he has built, and then goes across to a neighboring farmer’s field and does the same, showing dry, anemic dirt whose nutrients had been sucked out through conventional practices. Sometimes the comparison happens in an on-farm workshop with prepared soil samples, but the effect is the same.

While Montgomery (the scientist) is playing the role of the visiting extension agent, it is the farmers here who are playing the role of scientists. This is abundantly evident throughout the book, but just in case you didn’t get the point, Montgomery lets an Ohio farmer say it: “We can’t get a university … to look at cover crop varieties. So we’ve got to do our own experiments. … In my opinion, the university is twenty years behind us.”

The example that got me most excited was the perennial wheat being grown at Wes Jackson’s Land Institute in Kansas. I’d read about Jackson before, and I knew he promoted farming in ways that emulate the prairie, with its deep-rooted perennial plants that wouldn’t allow a speck of soil to erode away. I was delighted to discover from this book that, in an earlier incarnation, Jackson founded the environmental studies program at California State University in my own hometown of Sacramento. When I read that the Land Institute was attempting to market its perennial wheat under the name Kernza, I ran an internet search and discovered one could obtain a box of Honey Toasted Kernza Cereal as a reward for donating 25 dollars to support research at the Land Institute. They produced a limited run of only 6000 boxes. I got in just under the wire. It was tasty.

In his penultimate chapter, Montgomery takes the soil health movement one step further and considers efforts to compost not only animal manure, but human waste as well – what he calls “closing the poop loop” (I couldn’t resist including that phrase any more than Montgomery could). The surprise here is that human waste is already being commercially produced and sold – in Milwaukee, Wisconsin (a product called Milorganite), and in Tacoma, Washington (here it is called TAGRO – presumably derived from “Tacoma” and “grow”). Perhaps Montgomery saved this least-savory chapter until the end of the book, to make sure you were really with him that far. But I find him at his most eloquent when he articulates his utopian vision here: “Imagine trains coming into cities full of food, fibre, and fuel, and leaving full of compost, biochar, and biosolids, returning to the fields what we took from the land in an endless cycle.”

Montgomery dubs the return to soil health a “revolution” – the fifth revolution, as he reveals in his final chapter. I wish he had been clearer about which cycle of four revolutions he was referencing – there are at least three to choose from, of varying historical depths. I suspect here he is thinking along a deeper time horizon, and has in mind the initial domestication of plants and animals (which certainly transformed human societies); the Agricultural Revolution (17th-century innovations that increased productivity); the Industrial Revolution (come on – you know this one); and the Technological Revolution (generally marked from the invention of the microchip).

That means Montgomery is giving soil health a place among the great social revolutions of human history. He even issues a call for a “soil health moonshot” to transform conventional agriculture. Huzzah. I like his audacity. Given the increasing rate of global warming and the destructive potential of human behavior in this era sometimes called the Anthropocene, I think a change in human behavior to conserve the matrix from which we draw our very life – the soil – would literally be a revolution. Corporate empires would fall (I’m looking at you, Monsanto), and the lumpen gardener proletariat would rise. Let me live just that long.