Got Dirt? Get Soil! Ditch the Plow, Cover Up and Grow Diversity
The profit-hungry agribusiness empire of the 20th century institutionalized farming practices that continue to degrade soils across the U.S. and globally. We face a fork in the road: collapse or regeneration? The good news is that we know what we need to begin an agricultural and ecological renaissance – a literal rebirth.
Biologist Ann Biklé and geologist David Montgomery share one of the good news stories that show how the solutions residing in nature surpass our conception of what’s even possible.
David R. Montgomery, a Seattle-based MacArthur Fellow and professor of Geomorphology at the University of Washington and the author of award-winning popular-science books that have been translated into nine languages, is an internationally recognized geologist who studies landscape evolution and the effects of geological processes on ecological systems and human societies.
Anne Biklé, a biologist, science communicator, and public speaker, investigates and writes about connections between people, plants, food, health, and the environment. Her work has appeared in magazines, newspapers and radio, and her soil-building practices have been featured in independent and documentary films.
- Executive Producer: Kenny Ausubel
- Written by: Kenny Ausubel and Arty Mangan
- Senior Producer and Station Relations: Stephanie Welch
- Producer: Teo Grossman
- Host and Consulting Producer: Neil Harvey
- Program Engineer and Music Supervisor: Emily Harris
- Production and Engineering Assistance: Rebekah Wineman
- Production intern: Isabelle Dean
Learn more about David and Anne’s work and books at their website, dig2grow.com.
Explore Bioneers’ Regenerative Agriculture media hub to learn more about practices that increase biodiversity, build and enrich soil, improve watersheds, enhance ecosystem services, and increase soil carbon storage.
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This is an episode of the Bioneers: Revolution from the Heart of Nature series. Visit the radio and podcast homepage to find out how to hear the program on your local station and how to subscribe to the podcast.
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NEIL HARVEY, HOST: We’ve been treating our soil like dirt. The consequence is that it’s déjà vu all over again. All over again, we face both peril and promise.
The 1930s Great Depression was as much an environmental collapse as an economic bust.
Driven by insatiable capitalist appetites, plowmen farmed places that ought never to have been farmed and shredded fragile ecosystems.
They managed to strip the native grasses, a finely tuned symphony of perennial species that had evolved and flourished for over 20,000 years.
As author Timothy Egan wrote, “The tractors had done what no hailstorm, no blizzard, no epic siege of frost, no prairie fire, nothing in the natural history of the southern plains had ever done.”
By 1937, there were a record-breaking 134 dust storms that excavated the precious, scant topsoil, dropping 12 million tons of the black gold on Chicago and onto ships as far as 300 miles off the East Coast.
Overall, lands in 19 states had pretty much lost their topsoil. The barren Dust Bowl precipitated plagues of locusts, jackrabbits and green worms. Birds and snakes were no longer to be found.
It made a bumper crop of “Exodusters” leaving farms behind.
President Franklin D. Roosevelt warned this: “The nation that destroys its soil, destroys itself.”
He responded with a visionary slate of federal supports and innovations that revolutionized the beneficial treatment of the land – and of farmers. At least for a time.
Tragically, the same misbegotten, profit-hungry agribusiness empire institutionalized practices that have badly degraded soils across the U.S. and globally. And in this turn of the crank, the new twist is catastrophic climate change.
Once again, we face the same fork in the road: collapse or regeneration?
The good news is that we know what to do to begin an agricultural and ecological renaissance – a literal rebirth. And it starts right under our feet.
But we’re playing a dangerous game of Beat the Reaper, and it’s for keeps. So warned David Montgomery at a Bioneers conference.
DAVID MONTGOMERY: Soil erosion played a role in the demise of civilizations, going all the way back to the earliest agricultural civilizations in the Middle East to Neolithic or Bronze Age Europe to Classical Greece, Rome, Southern United States, Central America. I went through and sort of collated the archaeological literature, the historical literature, and the modern geological literature, because you can still go and see degraded soils in those parts of the world, and if you want examples, think Syria and Libya today. Those are places where we have Roman tax records of high harvests, several thousand years ago, where they cannot really essentially feed a growing population today.
And the problem was not what you’d generally find in environmental history textbooks. What you generally find is that deforestation caused erosion and degraded the land. The real problem was the tillage that followed. It was the plow, not the axe.
HOST: David Montgomery is Professor of Earth and Space Sciences at the University of Washington, and a MacArthur fellow.
As a geologist who studied soil erosion in natural systems, he decided to update the literature, which dated back to the 19th century. He spent four years on his book, Dirt: The Erosion of Civilizations.
He found a common thread in the archaeological and agronomic literature: The way human societies treat their landscapes is how the land will eventually treat their descendants.
Soil erosion and soil degradation inevitably undermine a society over time. They make it vulnerable to drought, climate change, political instability, food riots, and wars.
DM: Imagine what a plow does to the soil: It inverts it. It turns it over. And it’s intentionally doing this for weed control, because a plow is very good weed control. But it also means that the soil is left bare and vulnerable to erosion by wind or rain until something grows on it, whether a weed or the next crop. And that can basically add up over time.
If you look today at the state of the world’s soils, we’re losing about 0.3% of our ability to feed ourselves each and every year due to degradation of the soil. That .3% sounds like a small number. It’s probably about what we’re all getting on interest for our savings accounts. It takes a while to notice. But you play that out over the next 100 years, and that turns into 30%. We cannot afford to lose 30% of our ability to feed the world before our population goes up by 50%.
The soil carbon content of many soils in North American is only about half of what they were when they were first converted from forest or prairie lands to farms.
Iowa has lost 50% of its topsoil in the last 150 years. These trends are depressing.
It takes centuries for nature to make an inch of topsoil. We’re losing it in decades. Those numbers defy the definition of sustainability. We are basically bleeding topsoil. And this has been going on for civilizations around the world.
HOST: David Montgomery grappled with the fateful question: Could soil be restored to a fertile state and defuse the ticking time bomb of agricultural collapse?
He embarked on the quest with his wife Anne Biklé. She describes herself as an “out-of-bounds biologist” because she has applied her training in biology to fields as diverse as environmental planning, salmon restoration and public health.
Their joint exploration of soil restoration led them to co-author The Hidden Half of Nature: The Microbial Roots of Life and Health.
Their writing journey began when the couple bought a house in North Seattle. She desperately wanted a garden.
Anne Biklé spoke with us at a Bioneers conference…
ANNE BIKLÉ: Here’s the biologist and the geologist, both of whom have dug soil pits around in various aspects of our work, but we never really thought to dig a soil pit in our own backyard. And it was sick. It was not well. We had had some heavy equipment come into the yard, and they scraped everything out that was there. It fully exposed the soil. And everyone thinks, oh, Seattle, it’s all green and nice and everything up there. Well, our soil looked like it could have been out in New Mexico. It was kind of sandy-colored. It was really rocky, and there was nary a worm and hardly any organic matter. And it was the middle of August when this all sort of came to light, and we had a lot of plants on the sidelines waiting to get into the ground. And here we were with really some pretty dead dirt. That was a time of panic and a time of Uh oh, what are we going to do?
And I had done enough restoration in salmon watershed stuff, and I’d done enough gardening that I thought, okay, my gut is telling me that this soil is deficient in organic matter, so that’s going to be the number one thing that I’m going to start on is getting organic matter and getting it into the soil. And so that was not a highly technical kind of an undertaking in that I didn’t set about, you know, we need this kind of organic matter and that kind, and in these ratios and proportions, and so on. I really began collecting what was cheap or free in the neighborhood, and I began making all of these different mulch mixes.
And what is funny about that is that I am outside working my tail off trying to bring soil back to life, he is inside surrounded by books, looking out the window at me pushing this wheelbarrow that’s loaded, about to tilt over.
HOST: Her geologist husband was intently studying the history of how nature builds topsoil, and how it gets depleted in the first place.
Right under their feet in their own backyard lay the evidence of the geological history of erosion.
DM: Seattle is a place where from about 15 to 17,000 years ago, a glacier came out of British Columbia, marched south because it was snowing a lot in British Columbia, the ice piled up. You get a big enough pile of ice, it starts to flow under its own weight. And this tongue of ice came all the way out of British Columbia, overran Seattle, and made it all the way down to Olympia, well south of Seattle, buried Seattle under a mile high wall of ice. But what it had also done is it had laid down in front of that advancing glacier all the bits of sand and bits of eroded granite that had come with the ice but that didn’t melt when the ice melted, got reworked by streams in front of the advancing ice, and then overrun by that ice. And so what that did was it basically laid down a blanket of sediment and then compacted it into something that I like to think of as nature’s concrete, which is not the best soil.
After that, when the glaciers receded, it took thousands of years for the forest to come in and actually build a good soil on top of that geological concrete. Then when they cleared our neighborhood to build our house in 1918, what do you do when you basically develop a neighborhood? You strip off the topsoil and there, what was left underneath, was this glacial till, nature’s concrete.
But after Anne started what we call her organic matter crusade, of bringing organic matter back to our lot, what was it, maybe about three, four years into it that [ANNE: Yeah] we started to notice the color of the soil changing, and that the soil beneath the lawn that we’d sort of carefully put it in right flush with the patio that we put in, the soil was now about an eighth of an inch higher. It was fluffing up and it was getting darker. And so we were trying to figure out what was it that was actually turning that compost and mulch, all that organic matter that Anne was adding to the yard. What was turning that into soil organic matter was the intellectual journey, if you will, that we set off on in researching The Hidden Half of Nature, to understand, why was this happening? How was it happening? And that led us to the role of microbial life.
HOST: Although science has barely scratched the surface of this intricate underworld, we do know that a quarter of all species on earth live in the soil microbiome. Just one tablespoon of healthy soil has more organisms than there are people on the planet. We’ve identified only about 1% of soil microbial species.
Microorganisms provide ecosystem services including transforming so-called “waste” into organic material and valuable nutrients, and regulating the distribution of those nutrients among microbial species, fungi and plants.
That nutrient cycling is the basis for nature’s self-renewing fertility.
It’s a symbiotic exchange, as plant roots send carbohydrates back into the soil to feed the microorganisms.
AB: We’re going to go to a wild and alive place in the soil called the rhizosphere. Think of it like a halo that goes around each and every root hair of a plant. And I call the rhizosphere a biological bazaar. Folks, this is nature’s quid pro quo. In return, bacteria are feeding off of this stuff, they’re growing like crazy, and they are excreting waste products. The plant is getting something it really needs that it cannot make, or if it does it makes it in small quantities, and it feeds the bacteria and says, I need growth-promoting hormones, please.
And I want to talk about the fetching fungi. Fungi are attached one end to a root hair, and with the fungal hyphae, they’re prospecting. They’re getting minerals out of rocks that are in the soil. And one of the most important minerals is phosphorus. And it’s estimated by some there’s up to 100 years worth of phosphorus sitting there in the soil but plants can’t access it. The fetching fungi, they can get at that and they can transport it back to the plant, and they can exchange it. Here’s phosphorus, and I’ll take sugars.
Really the rhizosphere and the root system of a plant is—it’s the intelligence system. The brain for the botanical world is not on the top. It’s down below ground. It’s this symbiotic relationship between roots and bacteria and everything else. There’s ceaseless, constant communication between a plant and its soil microbiome.
HOST: The couple’s backyard revelation about the role of the microbial world transformed their view of nature and how she works. It brightly highlighted the power of the nurturing role people can play to create the conditions for life to flourish — and let nature do the rest.
DM: It turns out that the order that life came back to our yard parallels the order in which life evolved on Earth. Obviously different time scales involved, right, but it started to cement the idea in our minds that ecosystems are essentially constructed from the bottom up, and that that foundation of microbial life was really essential for supporting not only the life below ground but the life that we knew above ground. Because when we restored the soil, both came back.
We obviously didn’t notice the bacteria first because there’s a reason they’re called microbes. We can’t actually detect them with our senses. But we could start seeing their effects. And then we saw the organisms in the soil, and then the worms, and then the birds that came to eat the worms, and then the bigger birds that came to eat the littler birds, culminating in something that Anne saw one day when an eagle came and took a baby crow out of our neighbor’s tree. That baby crow had been living off the worms that were growing in the restored yard. And it was a real revelation.
People had known all those pieces before, but putting it together that way in the way that we witnessed it at our own place made us start to think about the bigger picture about, well, could you restore soil at the global scale?
AB: That’s the question right there: How quickly can we do this and how much time will changes take to get the results in soil that we’re looking for? This is based on the changes in the soil in our own sort of garden experiment. And we’re even now more years out and the soil has just continued to get better and better and better.
It can happen really quickly.
I would say soil is one of the very few good news environmental stories that we have out there because once you stop hammering at it and you stop chiseling away at it, and you let the biology come back in and start doing the nutrient cycling and all of the processing, soil can rebound quite quickly, in fact.
HOST: When we return, David Montgomery and Anne Biklé describe how that backyard experiment helped unearth a world-changing way to revolutionize agriculture that rapidly regenerates soil, sequesters carbon from the atmosphere, supports farmer livelihoods, and can authentically help feed the world.
You’re listening to the Bioneers: Revolution from the Heart of Nature.
HOST: David Montgomery and Anne Biklé found another benefit in their backyard soil restoration project. Anne’s work had not only increased the beneficial microbial activity; it had also put organic matter – which is about 50% carbon – back into the soil.
They asked the driving question: Could soil restoration be a potent method to sequester carbon and help reverse catastrophic climate change?
The book Drawdown, which documents proven methods to remove CO2 from the atmosphere, had concluded this:
“It is estimated that at least 50 percent of the carbon in the earth’s soils has been released into the atmosphere over the past centuries. Bringing that carbon back home through regenerative agriculture is one of the greatest opportunities to address human and climate health, along with the financial well-being of farmers.”
DM: So I took about six months off from teaching at the University of Washington, and traveled around the world to visit farmers who had already restored fertility to their land, to try and take the lessons of that first book, the science from the second book, and apply it to—see how well it could be applied to the problem of feeding the world and regenerating agricultural soils. And that resulted in the most recent book, Growing a Revolution: Bringing Our Soil Back to Life, which is sort of the third book in what Anne and I call our dirt trilogy.
HOST: David found that the farmers were doing much more than just adding organic matter. They were following three simple, but crucial, regenerative principles of conservation agriculture.
So the first principle is minimal disturbance, minimize disturbance of the soil, which often meant going to no-till farming or not plowing, because plowing makes the soil vulnerable to erosion, it oxidizes organic matter.
The second one is, keep the ground covered with cover crops. Always keep a living plant in the soil, in part, because the roots that are then maintained are pushing exudates into the soil to feed the microbes that partner with the plants in symbiotic relationships that help build the fertility of the soil and help the health and growth of the plant as well. And then the third piece is grow a diversity of crops in the same piece of land. Don’t just keep growing the same thing year after year, or even two things and alternate one or the other like the corn and soybean rotation across a lot of the American Midwest. That’s a recipe for inviting pests to a banquet.
So minimal disturbance, cover crops, and a diversity of crops. That defines kind of the new way of looking at farming, a new sort of foundational philosophy for agriculture that happens to be the exact opposite of what we’ve been teaching in agronomy for 100 years, where we’ve been teaching intensive tillage with a lot of agrochemicals and specializing in one or two crops.
HOST: These three principles of conservation agriculture comprise a suite of practices that build fertility and can reverse the erosion crisis.
In David Montgomery’s travels, despite diverse climates, soil types and conditions, he found that when farmers embraced these three disarmingly simple regenerative principles, they reaped practical benefits beyond soil restoration.
DM: Anne and I came up with this catchy slogan that we hope everyone will repeat and spread around the world: “ditch the plow, cover up, and grow diversity”, those three principles expressed a little more popularly.
When I visited Ghana in equatorial West Africa, Kofi Boa, the gentleman pictured here with his “Got dirt? Get soil” hat, which everybody needs one of, he taught the farmers in his area to go from their traditional slash and burn farming to doing no till with cover crops. They don’t use agrochemicals for the simple reason that they don’t have any money to buy them, and this is why the green revolution did not work for subsistence farmers around the world. It’s the wrong business model for them.
So what did Kofi teach his people how to do? A style of agriculture that involved polyculture in their fields, with minimal disturbance. They cut erosion by a factor of 20. Their corn yield tripled and their cowpea yield doubled. In other words, they got better yield returns doing conservation agriculture than the green revolution did.
And it doesn’t just work in Africa. David Brandt, the gentleman pictured here from Brandt Family Farm in Ohio basically has adopted these same kind of practices. He grows corn, wheat and soybeans for the North American commodity crop markets. But that’s not all he grows. He grows a very diverse mixture of cover crops in between his cash crops.
David has been doing no till for 44 years. He then moved into cover crops. He’s now hardly using any fertilizer, hardly using any pesticides. He’s not tilling. He’s using about an eighth of the nitrogen. He’s using about just over a third of the RoundUp. He’s made 400 bucks an acre when his neighbors were losing 100 bucks an acre. This is the kind of math that made me an optimist that we could actually change conventional into more regenerative practices.
Gabe Brown is the last guy I’ll tell you about. He’s doing something else. He’s bringing livestock back into the equation. He’s bringing cows in to graze off the cover crops that he planted in the field that he then planted his market garden for farmers’ markets in. Gabe’s another one of these organic-ish farmers who’s weaned himself at this point completely off of agrochemicals, and he’s done it because he doesn’t like writing checks to the fertilizer dealer.
HOST: No natural ecosystem has evolved without animals. Ruminants such as deer and elk have a symbiotic relationship with native flora and ecosystems, especially grasslands.
When ranchers and farmers use management practices that mimic natural wildlife patterns, domestic livestock can actually cycle nutrients and spread fertility, at the same time they live a more natural and humane existence.
But the soil crisis got baked into the economics when industrialized agribusiness disrupted that integrated system by mismanaging grazing patterns, overgrazing, and moving animals off the land into concentrated animal feeding operations, called factory farms.
DM: You can restore land without the livestock, but I’ve come around to seeing livestock as a potential accelerant for soil rebuilding if you manage the livestock. So it’s not so much that cows are bad for the land but how we’ve been managing our cows is bad for the land. It’s a people management problem.
So you look at those kinds of things and you can look at regenerative agriculture as a way to rebuild soil fertility by altering one’s practices. And that can happen on conventional farms and it can happen on organic farms. A lot of organic farmers till too much, they plow too much. And they limit the ability to raise the fertility of their own land by that.
HOST: Ditch the plow, cover up, and grow diversity. And reintroduce animals to farmlands. The biologist and geologist say these regenerative practices will revolutionize agriculture and cause cascading positive effects for both nature and people.
AB: If we take better care of the land, if as a consequence of every harvest, the soil is left better off and not worse off, it’s our hypothesis that human health could be enhanced and improved. We’re getting more of the micronutrients – things like minerals, things like iron, and zinc, and selenium, and potassium, and so on. That gets into our crops, that becomes a part of the food supply. There’s research out there and evidence out there that a lot of the food in the food supply is deficient in these things, and that is hugely important for how well our immune systems function, all kinds of human health repercussions there.
DM: Well one of the things that gives me great hope around the future of agriculture is that I think there is a growing movement among US farmers to adopt more regenerative methods. There’s some really basic principles of ecology and biology at play here that we set up our modern farming system to try and work against. And I think what we’re learning is that long-held bit of advice that nature bats last, and it’s much wiser to try and work with her on your team than to try and go up against her.
HOST: In reality, these regenerative agriculture principles are not backyard stuff.
In 2015 at the Paris Climate Summit, the French government announced its groundbreaking new national policy called “4 per 1,000: Soils for Food Security and Climate Initiative.”
By increasing soil carbon sequestration by just .4% per year, we could halt the rise in atmospheric carbon levels – and ultimately make agriculture carbon-neutral.
Within a year, over 100 nations, NGOs and groups had signed on.
Once again, the solutions in nature surpass our conception of what’s even possible.