 Hi, good morning. I'm here to introduce Dr. David Montgomery. He is a professor of Earth and Space Sciences at the University of Washington and a 2008 MacArthur fellow. Dr. Montgomery studies how the surface of the Earth changes over time and is a leading expert on the process of erosion, which affects everything from the highest mountains to the lowland soils. This work on erosion led him to investigate the relationships between erosion, soil fertility, and human civilizations, and ultimately to examine our modern civilization's relationships with soil. Montgomery has co-authored five popular science books, plus the geomorphology textbook used in Laura's Earth Surface class here at Gustavus. These books are available in our bookmark if you're interested. Montgomery is also a fellow of the American Geophysical Union and the Geological Society of America. He's traveled the world to observe farming practices, soils, and erosion. His scientific work includes more than 200 scientific articles and book chapters, and he's a frequent contributor to public conversations about science. Please help me welcome Dr. David Montgomery. Well, it's an honor to be here addressing you all today, and thank you for that lovely introduction. I'm a bit of an unusual person to kick off a conference on soils because I'm trained as a geologist. So what I want to take you through today is a bit of my own intellectual journey, going from somebody who is trained to think that soil was the stuff that covered up the good stuff, the rocks underneath, to someone who would spend my nights and weekends for the last 10 years of my life writing books like the ones that are up on the screen, books that emphasize the importance of soil for civilization and ultimately for our individual health. The talk I'm going to take you through, if you're depressed for the first 15 minutes, don't worry, it gets better. Because that first book, Dirt, is the one that looks at the history of soil abuse, in essence, back through the course of history. And one sentence synopsis is that societies that didn't take care of their land didn't stick around, they didn't last. That middle book is a book that I wrote with my wife. Here are some images of how in our garden we sort of learned that we weren't the ones who were restoring soil at our place. It was the microbial life in the soil, something that neither and nor I were trained to look at. The third book's the optimistic one. It's how you can take the lessons of that first book, the ideas of the second book, and how farmers around the world are already applying them to regenerate and rebuild the fertility of degraded land. So that's essentially the game plan from what I'm going to walk you through. But first, since I'm a professor, we have to have a quiz. Which planet would you rather live on? The red one or the blue one? Blue? Excellent. Full credit. So why is that? Well, it's blue. There's water on it. Earth has water. Mars has a little bit of water, but not enough to kind of roam freely. And it also doesn't have an atmosphere to roam freely and breathe. Those two elements that make Earth habitable are things that everybody's sort of aware of. The third one is the one that we don't tend to think very much about. And that's the soil. As far as we know, Earth is the only planet that has soil on it. And why is that? Because you can think of soil as the marriage of geology and biology. My wife's a biologist. I'm a geologist. We ended up writing about soil. It kind of makes sense. We have life on Earth that helps to build soils, and soils help support life on the continents. So why would a geologist be concerned about the state of the world soils today? This map from the UN from a few years back that we could quibble with the methodology that produced is actually a very nice visual representation of the state of the world soils. There's a lot of yellow and red on that map. And you'll notice the red is very degraded soil. Soil has been degraded to the extent that it actually impacts agronomic production if we weren't replacing native fertility with chemical supplements. But this is painting with a very broad brush, and it's not quantitative. And I'm a scientist. So what is the state if we look at some numbers? How does that add up? And there's been a number of studies. There's actually a wide range of estimates of how much of the world's agricultural land has been degraded to one degree or another. I'm just going to go for this talk with David Pimentel's work from back when I had just finished graduate school where they looked at, in the second half of the 20th century, agricultural degradation of land, the erosion of soil, and the degradation of its fertility had already compromised about some 430 million hectares of arable land, which is about equal to a third of the world's current crop land. That's an area about the size of China and India combined. And if you think about the problem of feeding the world for the foreseeable future, and when you're talking to a geologist, sustainable doesn't mean the next couple of years. Sustainable means being able to actually maintain it for quite a long time. However you look at it, we'd have a much easier time feeding the future if we had not already degraded what amounts to about a quarter of the world's total crop land, a third of what we have at present. And that's not a problem that's been solved. The most recent, well one of the most recent reports I can find that looks at the state of the world soils is a UN report on the state of the soil from back in 2015 that in the executive summary reported that we're losing about 0.3% of our agricultural production capacity each and every year to soil erosion and soil degradation. Now 0.3% is kind of a small number. It's probably about what we're all getting in our savings accounts right now. But if you think like a geologist and play that out over the next century, it adds up, 0.3% a year turns into 30% if you just go for 100 years. In other words, we're on course today to degrade roughly another third of the world's agricultural production capacity over the course of the century that we're actually living in. That's a trend that is not a good one and is likely to conflict with the rising human population. It's my contention that agriculture needs to change this century in some fairly profound ways and I'll walk you through my thought process but I also wanna start with basically emphasizing that this is not a new problem. This is a problem that has plagued societies around the world since the dawn of agriculture. It's just played out fairly slowly. That's what I talk about in the Dirt Book and that's really what got me into thinking about soils. Because when you look at the history of agricultural societies around the world, what you can unearth if you'll pardon the pond is that soil erosion played a role in the demise of many civilizations around the world. Tracing all the way back to Mesopotamia or Neolithic or Bronze Age Europe, classical Greece, Rome, the Southern United States, the list actually goes on. I cataloged a lot of that in the Dirt Book and that's not to say that soil erosion wiped out civilization after civilization. What I'd like to argue based on that book is that soil erosion set the long wavelength periodicity of the relationship between the health of the land and the growth and decay of societies. If you have a lot of fertile land and a small population, you can grow. If you have a large population, integrated land, it gets more difficult to sustain a society. That's essentially the argument that I was making in that book. And societies in the past have degraded their land to the extent that societies today are still paying for it. And if you look at environmental history textbooks, what you usually find is that deforestation was the culprit. What I basically came to the conclusion of in writing Dirt is it wasn't the axe that degraded soils around the world, it was the plow that followed. And why is that? If a non-fiction book can have a villain, the villain of dirt was the plow. And that may seem a little disconcerting, because after all, the plow is on the seal of the US Department of Agriculture. It's sort of what we think about as an icon of agriculture. But think about what it does to the land, what it does to the soil. It inverts the surface of the soil, breaks up the surface, you take a vegetated surface and turn it into bare earth. How many of you have ever wandered around in a native grassland or native forest and seen a whole lot of bare earth on the ground? Mother nature clothes herself in plants. And there's strong reasons for that. There's synergies between plant growth and soil formation where the one really helps build the other and vice versa. And the invention of the plow fundamentally altered the balance of soil production and soil erosion at the surface of the earth. You can think of soil as a system, much like your bank account. You have income, you have expenses, you have savings. When you think about the soil on the landscape, we have erosion, that's your expenses. You have converting rocks into broken up matter and merging that with biological material, the merger of life and geology, that is your income. And you have the standing stock of soil on the landscape, that's your savings. If we erode soils faster than we rebuild them, we're quite literally running out of them. But it takes a while. It's hard to notice day to day. But why would a geologist look at a freshly plowed field that a rainstorm had just hit? Like this field in my home state of Washington and the eastern Washington in the Palouse. I look at this and I see the soil just bleeding off the landscape. All those little channels that you see, they're called rills, you can erase them with a single pass of the plow. They're an agronomic nuisance, but they add up over time. In fact, they can add up dramatically in short periods of time. This is another photograph from the Palouse. It's a picture of a winter wheat field, just like that last one was before the crop came back in. And that fence in the upper right-hand corner is a fence that the farmer built around their water cistern back in 1911 when they first broke the prairie in that area and started plowing it. The only thing that happened on that field for 50 years was planted in winter wheat and fallow and rain came at sometimes inconvenient times and you could strip off soil when those little rills and it would go down and off the site or onto the bottom of the fields. This picture was taken in 1961, 50 years after the initiation of tillage-based agriculture on the field, and you may notice just to the right of that 1961, there's a little weird sort of black vertical line. That's a one-foot increment on a survey rod, on a stadia rod. This is a five-foot cliff that developed in 50 years from erosion from those rills and because the plow will push soil downhill with each pass little by little. Five feet of erosion in 50 years, that's about a foot a decade, that's about an inch a year. There is nowhere on earth where soils form that fast other than my wife's garden and perhaps your farm, but we'll get there. How big an effect can this be over time? I hope that you're sitting there going, well, Dave, that is a very extreme example and of course it is, that's why I use it. It makes the point I wanted to make. But how typical is it? That's the real question. So let's look at the American Southeast sort of going from Virginia up there in the upper right down to Alabama in the lower left, that gray noodle that you see on the screen is the Piedmont Country, the Hill Country, the Upland Country. It's the places where there's enough of a slope that if you strip the vegetation off and rain falls to the grounds bare, you ought to expect some erosion to occur. How much has happened in the last couple hundred years since the plow arrived in the American Southeast, one of the original bread baskets of American society? Well, you'll notice that's a lot of gray, four to 10 inches. How much rich black earth was there when it was first farmed? Maybe a foot, six inches to a foot. If we could strip off a third to all the topsoil off a fairly broad area of our country in just a couple hundred years, think what the Greeks and the Romans could have done a thousand year run at their landscape. Think what the Mayans could have done. Think what the Chinese did, the home of original Chinese agriculture. It starts to put into perspective that the idea that societies could quite literally plow through their natural endowment of fertile topsoil is not a crazy idea. It just happened slowly enough that we don't notice it day to day, but it adds up over time. But there's another aspect to soil fertility that I don't want to overlook. This is a set of soils from a tobacco field in North Carolina. It's in that gray noodle that we were just talking about. And I visited it as part of an episode of the television show NOVA a few years back where I got a call from the producers saying we're telling the geologic story of North America and we're almost done, but we kind of forgot about something. We forgot about the soil. So what could we do in about five minutes or less because that's the way TV works that you could essentially tell the story of topsoil in North America? And I sort of like, wasn't quite sure. I called Ray Archuleta to consult with him. I go, what should I do? And we basically, oh, go to a tobacco plantation in that gray noodle, go to the middle of one of those tobacco fields, dig a hole, put the soil on a white tablecloth, then go into the neighboring forest that hasn't been farmed in 120 years and compare them. Which do you think is from the forest? Well, it's the one that is on your left, the darker milk chocolatey one. It's the one that has organic matter in it. The one on the right is the one from the, the one that has been treated with conventional agriculture for a century. And you'll notice they look different. It's the same parent material. It's the same rocks, but the one from the conventionally plowed field looks a lot like beach sand, because it is, it's 10 million year old beach sand. There's no organic matter though. If we look at the loss of organic matter in our nation's soils in the last couple hundred years, we've lost about half of it, about 50% on average. And that's not a bad number for agricultural systems around the world. That degrades the innate native fertility of the land. So of course, I'm a, I'm a practicing scientist. I teach geomorphology at the University of Washington. What I've told you so far is a bunch of anecdotal stuff. And in putting the dirt book together, I wanted to look at what is the data from modern science that actually documents how fast are the world's top soils eroding? So I did something that is not often done anymore. I went to the library and I went there for three weeks when my grad students were in the field and I gathered up all the data I could find about how fast are the world's farms eroding? How fast are the world's soils being built? And how fast have landscapes eroded over geologic time? Because over long periods of time, those must be in balance because our first order experience on this planet is almost everywhere we go has some kind of soil on it. And geologic time is long enough that if those are out of balance, it either stripped the soil right off the land and our planet would look a lot like Mars in the continents or we'd be buried under broken up rocks and dead things. But no, we find soil almost everywhere. So what did I find? I've boiled that study down to the single graph because I don't want to show a whole lot. My publishers told me no graphs, no charts, no tables in a popular science book, but I wanted to know about the data. This is what it came up with. It's measures of erosion rates in soil building. That number at the top, the one that's colored red is the average erosion rate for conventional farming and by conventional, I mean till-based agriculture, plow-based agriculture. And the numbers and parentheses on the left after each of those entries, those are the number of peer-reviewed academic studies I averaged to get the number on the right. So you'll notice there's a lot of Xeroxing involved in this project. Millimeter and a half a year erosion rate, global average for plowed fields. That's a small number. Your fingernails grow faster than that. The San Andreas Fault moves faster than that. I have no desire to ever see it move again. The big message of this figure though is that those blue numbers are a lot smaller. Erosion rates under natural vegetation. You're looking at hundreds of a millimeter. Orders of magnitude smaller rates of erosion. Rates of soil production. They're kind of close to erosion rates under natural vegetation. There are strong reasons for that. Read the papers and the proceedings of the National Academy of Sciences if you really want all the data. And if you're a student thinking about doing a project on this, you can just steal my data out of the spreadsheet. We published it, it's online. You don't have to redo this. You can supplement it and send me your spreadsheet. That'd be great. Long-term geological erosion rates that are right in the ballpark of natural erosion and soil building. There's good reasons those things are all comparable. But look at that number at the bottom. That's where the good news lies. Because that's the erosion rate under no-till agriculture. I've painted it blue because it's a lot like those natural rates. In other words, the good news is that we know how to farm in ways that can actually reduce erosion so that we would not repeat the experience of ancient civilizations. The bad news is that those methods are called alternative agriculture. So I've given you the data so far that you can actually do the calculation for yourself. If you have a pencil and a napkin, there's pencils and papers that were going to be passed around earlier. You can check my math if you'd like. But that net soil loss globally of roughly a millimeter a year or so will be conservative, I could argue, for a millimeter and a half. But if a millimeter a year, you could shed a half meter to a meter soil. That's about a foot to three foot soil thickness that's typical on most hillsides. Check the UN Global Soil Database. It would only take about 500 to 1,000 years of cloud-based agriculture on average to erode that soil right off the land. And this has happened in different regions around the world time and again. And it turns out that that's approximately the lifespan of most major agricultural civilizations viewed through the plus or minus 50% is okay because I'm a geologist kind of lens. And there's really big exceptions that I hope you're thinking about because we know of societies that have thrived farming for thousands of years. Where do most of them tend to be on big river floodplains, the Tigris and the Euphrates and Mesopotamia, the Nile in Egypt, the Indus and the Brahmaputra in India, the big rivers of lowland China flowing off the Tibetan Plateau. And there's a really simple and profound reason why those societies were able to practice agriculture often with tillage in those landscapes for a long period of time. And it's buried in that word, floodplain, because what happens on a floodplain? It floods, right, yeah, it's buried right there in the name. Now, how big is a grain of sand? Roughly a millimeter. Yeah, a small half that to two millimeters. What was that average erosion rate globally from Ploughbys to agriculture, millimeter and a half a year? You could deposit a single grain of sand on an agricultural field and you're basically over time on average, you could replace the fertility you'd lost through soil erosion. It's a simple reason why agriculture was able to be maintained on river floodplains. It's a natural environment that's incredibly resilient to that style of farming. It's when you get to farming on landscapes that are outside of floodplains that the erosion clock kicks in. So I also hope you're sitting there thinking, well, okay, you promised to turn this around and make it not a depressing talk. How are you gonna do that? Writing the Dirt Book started me thinking about, well, is soil restoration feasible? Could we actually reverse the global pattern that we see if we look back through history? And the place that I learned that, of all places, was my own yard. Because my wife, the biologist, is a gardener. And when we bought a house in North Seattle back in the late 1990s, it came with a degraded soil that I'll show you in a moment. But we wrote about that experience of her restoring the life in our yard, rebuilding soil fertility in the hidden half of nature, the second part of this trilogy of books about soil. This shows the side yard that our house came with and what's one of the reasons we bought the house is that this was obviously great space to make a garden. I liked the lawn. You could play with the dog and a ball and you'd chase it and wanted a garden. We stripped the lawn off the yard and we had this sort of really nice, rich black soil that you have around here. Now, we had dirt. There wasn't a single worm beneath that lawn and there's a reason for that. We live in Seattle where a glacier scraped the landscape clean about 15,000 years ago and then developers scraped it clean when they built our house. The top soil was totally removed. We had the mineral part of fertile soil. We didn't have the biology. Fortunately, I'm married to a biologist. She decided that what we needed to do is go on an organic matter crusade and get as much organic matter as we could find and reintroduce that back into our yard to try and build the soil up. Originally, it was to mulch the soil to hold moisture in because water rates are high. We had a bunch of new plants we planted. We didn't wanna pay for a whole lot of water. We painted the wheelbarrow up because it goes faster when you do that and started collecting wood chips from Arborus. We collected what's called Zudu from the Seattle Zoo and borrowed my truck, entered the lottery for Zudu to get composted herbivore manure from the Seattle Lottery. She won the lottery, so my truck got used for that. And then she kept entering. We kept winning and we kept winning and I think you always win the Zudu Lottery. They have stuff to get rid of. This shows you briefly the kind of stuff that we used. We took wood chips and compost. We composted our kitchen scraps. We got a worm bin and we cycled our own scrap food through that, put it back in the yard. We raked up our neighbor's leaves. We used that Zudu. There's coffee shops in every street corner in Seattle so we had a great source of used coffee grounds that they wanted to get rid of. They just show up at the end of the day, haul them away. Organic matter, organic matter, organic matter back to the yard. What happened? This shows you the difference in about 12 years of intensive organic matter returned to the yard. In what is on the left side of the screen, my right hand is the soil we started with, about 1% organic matter. My left hand is what we have today. It's about 10% organic matter. We put tons of carbon in our yard inadvertently in an attempt to restore life to our yard. What I was shocked by as a geologist is this is the opposite of that field in North Carolina that I showed you. And we were able to do it in 10 years, roughly a decade. This is screamingly fast for a geologist. Things don't tend to happen that fast. And I got really interested, and Anne got really interested in what was going on. Because we were just putting organic matter on as compost and mulch. We weren't digging it in. We weren't using any fertilizers. We were just kept on adding organic matter. It would break down and disappear. And so six months later, we'd add a whole lot more. And that started us looking into what was happening in the yard. And we ran into terms like the rhizosphere, the root, the zone around the roots of a plant. And it turns out that's one of the most life-rich areas on the planet, around the root system of a plant. And as we were reading papers on what's happening in the root zone, we ran into this term called exudates. Now, plants, it turns out, have a monopoly on photosynthesis other than microorganisms in the ocean. But on land, they're able to essentially capture carbon dioxide, combine it with water, turn it into carbohydrates, and build the building blocks and structures of organic life. But they also need other things. And oddly enough, we ran into the data that showed that plants will push out of their root system, will exude out of their roots, sometimes 30% or more of the stuff that they manufacture through photosynthesis. How many of you take 30% of your income and just give it away to other people, and I'm not talking about taxes? Because you actually, you like it or not, you do get something in return for taxes. You may not get as much as we want. But plants are not doing this simply to do it. They're doing it to feed the life in the soil. They're feeding the microbial life in that rhizosphere. Or maybe what I should say is the reason that the rhizosphere is so dense with life is because plants are exuding these things. What are they exuding? Carbohydrates, proteins, there's even a study that showed they're exuding lipids. What does that sound like? Carbs, fats, and proteins. It's food. Breakfast, lunch, dinner. Plants are pushing food out into the soil and they're not doing it just to do it. They're doing it in part to feed the microbes in the soil because they get something in return. And in fact, if you look back at the earliest land plants that we have fossils of, they have mycorrhizal fungi wrapped around their roots. There's long-term partnerships that have developed in the soil between plants and soil life, microbial life, the bacteria, fungi, protoss, archaea, that benefit both parties. And how that works is Ananiyne termed it a biological bazaar because it's the original underground economy. So that sort of noodle over there, the orangey thing surrounded by purple, that's meant to be a root tip that we're blowing up on. All those little red things are bacteria. That purple stuff are the exudates flowing out into the rhizosphere and they don't make it very far. They only get about a millimeter to a centimeter away from that root tip before they get consumed by that life in the soil. Somewhere between the thickness and length of my thumbnail. And what happens to anything that an organism consumes? It gets metabolized. And when it's metabolized, it's turned into something else. What kinds of metabolites are organisms in the soil producing? The one that blew my mind was they're making plant growth promoting hormones. There's a whole bunch of other ones we could talk about, but in the interest of time, I won't go into them. But think about that one for a minute. You've got single-celled organisms in the soil from a completely different kingdom of life, making hormones that promote the growth of plants. And they're doing it for a simple reason because if the plants grow and are healthy, they photosynthesize more, there's more exudates, the microbes get fed, it's a beneficial loop, positive feedback system. What kind of things are those microorganisms doing? They're bringing mineral micronutrients to the plants. They're providing chemical signaling compounds and other things that benefit plant health that also benefit plant defense. Because sometimes when an herbivore will nibble on a plant, the plant can either produce a phytochemical that helps repel that insect with help of microbial stimulation signaling in the soil or sometimes compounds will come into the plant through while the plants will exude compounds that feed the microbes and there's this feedback where it can actually help repel that particular insect pest. There's highly specialized adaptations and relationships in the soil that have been out of sight and out of mind because they're below ground and they're microscopic but that they're fairly parallel to what we know about in the world above ground between, say, flowers and pollinators, mutually beneficial interactions, symbiosis. So this led us into looking at symbiosis and it also led us down the road of thinking about a plant's diet. How many of you have ever thought about what plants eat? We don't tend to think about plants as having a diet or it mattering for their health but it does and it turns out it matters for our health too and that's a book that Ann and I are working on finishing now. But when you think about the diet of a plant, over on the left there's what we call the fertilizer diets, the diet they get in conventional agriculture these days and most of the developed world and when you take a plant and you feed it most of the major elements that it needs, the typical NP and K that you need to promote plant growth, it doesn't invest so much in the root system and you can run that experiment on a farm if you want by just going and trying to pull up corn plants that have been really, really well fertilized. They don't invest in the roots. So if a plant doesn't invest in its roots, it's not producing as many exudates because it's getting the main things it needs to grow but it's not getting all the things that the microbial life in the soil was providing that benefit its health. It's not getting as many mineral micronutrients and it's not getting at many of the beneficial microbial metabolites that bolster its health and defensive system. The soil health diet, the diet on the right, if you have a plant that's growing in a very organic matter rich soil, it doesn't need as much of the major elements because it can actually get more of them but more importantly, it's getting more of the mineral micronutrients and the beneficial microbial metabolites. There's a very real reason in other words why after the advent of major nitrogen fertilization in the developed world, the demand for pesticides went through the roof because if anyone is familiar with Star Trek or Star Wars, we took the shields down of our plants. We disabled their natural defensive systems by compromising their relationships with microbial life in the soil. So what does this mean? What does this all mean for essentially agriculture at a global scale? And this is where we start to get a little more optimistic because based on what we were seeing in our yard that we could bring soils back to life remarkably fast, I took about six months off from my job at the University of Washington and went around the world to interview farmers who had basically already done what we'd done in our yard but done at scale on farms and I wanted to ask what they had done, how did it work? And what I basically found was that there were ways for farmers to actually produce yields that were competitive with or better than conventional using far less diesel, far less fertilizer and far less pesticide, following a simple set of principles. And so to let the cat out of the bag of, well, what are those principles, Dave? It boiled down to really three things, minimal disturbance, so you could think of that as no-till agriculture, farming without the plow, maintaining a permanent ground cover, that's planting cover crops, keeping the ground covered with the living plants that will produce those exudates that help feed the microbes and also shield the land from erosion and planting a diversity of crops. And I could go, I could talk for hours about the reasoning behind all three but I'd be dragged off the stage and that would not be a welcome spectacle. So let me introduce you to three of those farmers and briefly sort of summarize their results because following those three principles was the recipe that farmers that were successful in various parts of the world, Africa, Central America, across North America followed, they all used different practices but they have followed those same principles. Dwayne Beck up here on the screen now from Dakota Lakes Research Farm in South Dakota as a person I visited first and I went to his place because his neighborhood is on the cover of my dirt book. It was hammered by the dust bowl. It's hardly, there's hardly any tillage that happens in his neighborhood anymore because years ago he discovered that no-till was a better way to go and then started getting into cover crops, started getting into a diverse rotation and he was able on his experimental farm to show that he could reduce the inputs of diesel fertilizer and pesticides by more than half and actually maintain crop yields. You can check out the traditional yield versus the complex rotation yield that's on the screen now. The soybean yields went up, the corn yields went up. In other words, they didn't use, lose yield by going to these more environmentally friendly farming practices. In fact, they saved a lot of money by spending less on diesel fertilizer and pesticide. It was more economical for farmers. That's a winning recipe. If you can spend less to grow as much if not more. I also visited Kofi Boa in Ghana. An amazing gentleman who had studied at Nebraska, learning no-till, brought it back to his native village outside of Kumasi and taught the local farmers how to go from their traditional slash and burn practices, Swidden style agriculture, to essentially farming with no-till with cover crops. And what did that do? Well, it shut down erosion. Look at the numbers up there. Dropped erosion by a factor of about 20. What happened to their yields? Their corn yields tripled, their cowpea yields doubled. This is without any assistance from Green Revolution type technologies. These folks are not using fertilizer. They're barely using any herbicide. They use it when they need it. It was a change in thinking, a change in mindset, a change in how they approached the problem of farming, going through that no disturbance, cover crops, and a diversity of crops. They used completely different methods than Dwayne Beck. The results were comparable. David Brandt, a farmer near Carroll, Ohio is another person that I'll share his experience quite briefly with. I visited him, in fact, in the company of Ratan Lal a few years back, and David walked us through the economics of his operation versus his neighbor's operation. He likes to think of himself, I think, as a micro-brancher. He doesn't have livestock that's visible. They're all invisible. And he feeds them with things like that, tillage radish that he has holding in his hand. Notice that his field in the foreground looks pretty green. Look at his neighbor's field in the background. Hopefully it shows up in this light as sort of yellowish soybeans with about maybe a quarter of it is green. All that green stuff, those are glyphosate-resistant mare's tail weeds, not a crop. It's a direct drag on his neighbor's harvest. So David walked me through what he's done. He's been no-till for about 44 years. He's got plants of diverse mix of cover crops, up to 12 crops in a field. And he has a complex rotation because of that. And he grows corn, wheat, and soy that he sells in the commodity markets. He's not doing the farmers market thing. He's sort of competing with the conventional neighbors. And he's out competing them for the reason of those numbers around the screen. It'll walk you very briefly. His neighbors are full-tillage, so they're spending a lot in diesel. They use 200 pounds of end per acre and 2 and 1 half quarts a roundup. Their total cost in 2015, the year I was there, was about 500 bucks an acre. They got about 100 bushels an acre. At $4 a bushel that they were getting in the market that day, they were losing $100 an acre. Even an academic geologist can tell you that really is a bad business model. The harder you work, the less money you make. He would have been better off in an anecdote that Jonathan Lundgren told me once, that if he just planted a single pumpkin and sold it for Halloween, he could have made six bucks and done hardly any work. What does David Brant do? Well, with his 44-year-old no-till with cover crops, he's not tilling at all. So he's saving half on diesel right there. He's using 24 pounds of nitrogen. He's saving on that. And he's using about a fifth of the roundup that his neighbors are working with. He's not an organic farmer. I was afraid he might hit me if I called him organic. So I teased him that he was organic-ish. And he liked that. His cost was 320 bucks an acre. He was out-yielding his neighbors by a lot, in part because of the mare's tail weeds. And at $4 a bushel, he was making 400 bucks an acre. He's doing fine. He's profitable. His neighbors aren't. He's puzzled why they're not emulating him. Frankly, so am I. What was the trick to David's success? The soil labeled 2014 is the soil that he had sort of the year before I visited. The one that's labeled 1971 was his neighbor's soil. It's roughly what David had when he started. There's no coincidence that David has now bought the 40 acres off his neighbor's farm. The difference is it's that same color difference, right? You've got the khaki stuff that has hardly any carbon in it. You've got the dark stuff that's fertile and full of carbon. He restored fertility to his land because he was using that recipe of minimal disturbance, cover crops, and a diversity of crops. I'll share with you one more farmer before I wrap up. Gabe Brown is a rancher and farmer in the outside of Bismarck in North Dakota. And he practices what he calls regenerative agriculture, which I think is a fabulous term. He's rebuilding the fertility of his soil. And he's using a different kind of tool than the other farmers that I've talked to you about so far. It's something that can accelerate the process of soil rebuilding. And it'd get a hint by that cattle sitting on his Brown's ranch. Yeah, he's reintroduced livestock, chickens and cows to his fields. He uses the cattle to essentially graze off his cover crops to kill those. And then they have cows you can think of as self-propelled methane digesters. They're taking those cover crops and they're converting them into more plant-accessible forms that are spread around in the manure. And the chickens help eat bugs out of the manure and they can make more money selling eggs as well. But he's basically demonstrating that livestock can be a tool of soil rebuilding and regeneration. We all too often hear about the negative effects of cattle on the landscape. Turns out that the problem isn't the cows, it's the way we manage the cows. And I'll spare you the details of that. We'll probably get into that a little later. But let me just show you his soil. In his right hand is Gabe's soil from that very field that I was showing you. And his left hand is a soil from his neighbor's organic farm. Which one looks better? Gabe's another one. He's one of these organic-ish farmers. He's not an organic farmer. But his soil is a lot better than his neighbor's. Why is neighbor's plow a lot? And that helps burn up organic matter. So what I came away with in sort of this visiting to farmers around the world are three simple pieces of advice for how to regenerate soil fertility. Ditch the plow, cover up and grow diversity. It's a recipe for doing what? It's a recipe for feeding the microbial life in the soil. For building up the fungal and bacteria populations that actually benefit the crops and crop health that can boost production. And that's why all those little microbes are dancing up there on the screen around the other caveat that I learned is that these general principles seem to work universally. In the developing world, the developed world, at the tropics, the temperate zones, large farms that were up to 20,000 acres that I visited, small subsistence farms in the developing world, the practices were totally different on each farm that I visited. You have to adapt those principles to the local landscape. So taking these ideas and doing it in this neighborhood in Minnesota, you'd have to figure out how to actually apply it. I'm not the guy to tell you how to do that. I'm the geologist that will interview people, stand back and go, what are the general principles? But I want to emphasize that this is not a question of organic versus conventional agriculture. It's about understanding how to apply knowledge of soil ecology to building and maintaining soil fertility such that one can use less diesel, less fertilizer, less pesticides. And it works. And the reason I know it works is I visited places where it's been done. It's not a theory. There's great examples hiding right out there in plain sight all over the world. Where does this leave us? Roughly, let's look back at the history of agriculture through the eyes of a geologist thinking about how many agricultural revolutions we've been through. I think we've been through four so far. The first was the idea of farming in the first place, cultivating and tilling the land. That was radical, revolutionary. The idea of soil husbandry, planting legumes, doing crop rotations, bringing livestock into the fields to graze off the crop stubble. That was developed in different regions of the world quite independently at different periods of time. And I call that sort of the second revolution. It was diffuse across space and time. The third revolution, in my view, is mechanization and industrialization that transformed agriculture in the 19th on into the 20th century. There's no real argument about that mechanization and agrochemistry changed agriculture in a big way. And the fourth revolution is the ongoing biotechnological revolution. The Green Revolution of the late 20th century, coupled with the ongoing genetic engineering revolution that has radically altered agriculture as well. What I think we're poised for, though, is the recognition of soil health as a driver of the fifth agricultural revolution. Because we've learned enough now about microbial ecology to actually think about how we can marry the ancient wisdom of crop rotations and cover crops. Those are not new ideas. They're back in that second agricultural revolution. But marrying those technologies that allow us to do the minimal disturbance parts, getting those to work with no till, that's where the new revolution lies and how getting those all three pieces together. Because we finally have the technology that we can marry with that ancient wisdom. And what can that help us do? Well, it can help us, I think, restore farm profitability. All the farmers I visited who had restored fertility to the land were more profitable than the neighbors by a large stretch. And this is something that I think could be very useful for many rural parts of the world. It can help us feed the world sustainably because if we can actually build soil fertility as a consequence of farming, we can turn around that long-term historical pattern of degrading the land to feed ourselves. And in a 10 billion person planet, we need to learn how to sustain farming, how to build fertility as a consequence of how we farm. In terms of climate change resilience, you'll notice the color changes in all those soils I showed you, going khaki to black, that's putting carbon in the ground. We could argue till the cows come home about how much carbon you could put in the ground globally, but the same practices you would do to rebuild fertility are the practices that will put carbon in the ground. We should put as, frankly, we should put as much in the ground as we can, keep it there for as long as possible. And it would also help reduce things like nitrate pollution offsite and farms, which would help relations between urban and rural environments all around the world. I'll leave you there if you're a Twitter person, live tweet the whole thing, use at dig to grow, that's my wife and I's Twitter handle. And if you're interested in any of this stuff, obviously as an author, I'm gonna recommend you read the books. Whether you get them from the library or buy them here or whatever, the whole idea is to spread ideas because I think that we're at a point where we could really benefit from this fifth agricultural revolution and the cards are lining up. I think we could actually pull it off over the next few decades. And to a geologist, that's really fast. So thank you very much for your attention, it's been an honor to talk to you. Okay, sure. Thanks so much for getting us off to a great start, David. I would invite the panelists to make their way up here to the stage for our first discussion. And I would invite the audience to do two things. First, there will be appearing on the screen on address you can go to, to find our audience poll. And after that question has been up for a little while, we will switch it to the address to which you can send your questions. And again, a reminder for those of you in the room, you can always use paper. I wanted to add one more thanks to another of our conference sponsors and the discussion of tillage radishes makes it a perfect segue. The Albert Lee Seed House in Albert Lee, Minnesota is another sponsor of the conference to whom we are very grateful. And when you say to yourself, where exactly do you get tillage radish anyway? The answer is the Albert Lee Seed House. So, if you all want to join us on the stage, we will have a small pause. So if you'd like in the audience to stand up and stretch, that's a good time to do that also.