Jesse from Hiwassee and Natalie Forstbauer of Heart & Soil spoke with authors Anne Bikle and David Montgomery about the evolution of their understanding of soil and health, their four published books and what food production might look like in twenty years.

Jesse

This afternoon we have the privilege of speaking with David Montgomery and Anne Bikle. They are prolific authors, as you can see, by the books in front of me, and have spent a lot of time and effort educating people on the benefits of healthy soil and all the different implications of that in many different facets. Their four books all get into that in slightly different ways. Awesome to have you.

David

Well, thank you. It's a pleasure to be here talking to you.

Jesse

Great. At the beginning, could you give us a brief synopsis of what you might call your soil health journey? How did you get into this whole field?

David:

Back when I was an undergraduate in college, I picked up a book in the bargain bin at the University bookstore called Topsoil and Civilization. I was a geology major. My professors advised me to ignore the soil because the interesting stuff was underneath. I picked this book up because it cost a dollar and I needed something to read over the break. I read it, and was like, wow, soils are the foundation for civilization. It's an idea that's been around for a long time.

Eventually that catalyzed my researching and writing the book Dirt, the Erosion of Civilizations a few years later. By then I'd become a professor and studied erosion more formally, the here and now geology that shapes the land. Researching the Dirt book, I looked at the way societies have treated their land in the past. I thought I was writing a history of soil erosion, but I ended up writing a history of farming, how society after society farmed the fertility out of their land until it impoverished their descendants.

I'd had the good fortune to marry Anne. We bought a house in North Seattle, and she's a gardener. She wanted a garden at this new house that had a crappy yard with crappy soil. She undertook to restore the soil in our yard. As I was finishing writing a book about the degradation of soils through history, she was restoring the soil in our yard, and doing it at a pace that you don't find in soil science journals. It takes nature centuries to make an inch of fertile soil. But if you already have the broken-up rocks and mineral matter, you can add the biology back much faster. That was the lesson I took from watching Anne and her regenerative gardening practices, which led us to write The Hidden Half of Nature.

That got me thinking about whether you do the same thing on farmland as Ann had done in our yard, which led to writing Growing a Revolution.

Then the two of us had questions about what regenerative farming might mean for our food. How does the way we farm affect the nutrient density of what gets into us and thereby human health? That led to writing What Your Food Ate. Anne and I have been on a long journey together. Looking into this stuff, we never imagined we'd write four books about soils when I started researching dirt.

I think the dynamic part of these books is the integration of biology and geology, because that's what makes for healthy fertile soil. This little library that's sitting on your desk has been a collaborative effort between Ann and me for the last ten or fifteen years as we learned different disciplines and applied her biology and my geology to the problem of restoring and rebuilding the fertility of the world's farmland soils.

Anne:

Unlike Dave, I didn't pick up a book that sounded boring and think, “wow, this is interesting." My whole journey into this began as a hands-on experience. As David mentioned, I started building a garden at our first home in Seattle. I'm a big plant person. That's where I have always connected with the natural world, with things I can get my hands around and I can look at and eat: real tactile things. I had done a good job of researching and selecting all the plants. Then the day came to get the plants in the ground and we went, oh F, this soil is not what it should be. Are these plants gonna die? Quite frankly, this was huge embarrassment for the biologist and the geologist.

The plants took over and there we were looking at our dead dirt. I had done enough gardening and growing plants to know that if I could lay my hands on a little bit of organic matter, and at least get something on top of the soil, maybe this was a place to start. It just took off from there. From that point forward David and I began to ask questions and wonder about all the things that live in soil, what they need and how human activities either support that or detract from that. That is a journey that can take you a lot of places.

Jesse

But the answers must not have been readily forthcoming to the point where you felt like you had to write the book on it yourself.

David:

One of the classes that Anne and I took together in graduate school was a soil science class. Most of what we were taught about fertility was related to the physics and chemistry of soils, which is all good stuff, but watching Anne's gardening restore life to our yard highlighted the role of biology and microbial ecology in particular. We recognized a gap in our training right in the interface of biology and geology. I've always been interested in the interfaces between disciplines, because that's often where there's secrets of understanding, and places to make advances by connecting what one discipline is ignoring that another one has discovered that's relevant to the first one. We got sucked into writing about microbes because we realize that those are the things that were rebuilding the soil in our yard.

There was a freshness of discovering, not new knowledge for humanity, but new knowledge for us. I think our role in writing these books is to connect the dots for ourselves and for other people, and to translate the stuff that's in scientific journals into English that people can understand.

We're scientists, we're trained to write in a boring fashion for journals. Editors will insist on that. This one paragraph that we highlighted at the start of The Hidden Half of Nature that is straight out of a journal of nature or something. If you read it, it’s all acronyms and it doesn't mean anything, and who could possibly understand it. But when you parse it and get into it, it was this incredible story about how the food we eat is metabolized by microbes into things your body takes up, that then bolster your immune system and make you healthier. But you'd never get that as a layperson from just reading the scientific article, right? It's written in the language of the priesthood.

A big motivation for us is to understand more than we knew at the start of a book. Each of the books has an argument we're making based on drawing together science from multiple disciplines to shed light on something we think people should know more about.

Jesse

Excellent. Could you walk us through your books in the order you worked on them? What points were you making? What did the research look like? I know at least for Growing a Revolution you traveled quite a bit to meet a lot of people to put that together.

David

I’ll let Anne describe the two that she co-authored, but with Dirt, the one that got us started in thinking about soils, I was very interested in writing a broad sweep of history of how surficial geology, the geology I study, influenced human societies in the post-glacial world. The more I looked at the archaeological record and what's still written in soils around the world, the more I realized that the history of humanity is written in the soil we've left behind. The basic lesson of that book is that societies that don't take care of their soil don't last. There's a very strong connection there.

The reason this is important today, of course, is that we don't have any fresh places to go. We're pretty much farming everywhere in the world that could be farmed over the long run, and we're degrading a lot of it. That got me worrying about what are we doing now relative to what societies in the past have done. But Dirtwas a very backwards-looking book. It's the book you might expect a geologist to write about soils. It's a history of the last 10,000 years and how people have affected soils and how that in turn has affected societies throughout the ages.

That set up looking into The Hidden Half of Nature with Anne. I'll let you do that, and then I'll go back and describe Growing a Revolution.

Anne

Sure. After the garden had been in for several years, somebody came around and said, "Have you ever thought about putting your garden in the neighborhood garden tour?" "No, what's the neighborhood garden tour?" We put it in there and I had to write up something for it. Of course it was it was way too long and Dave was reading it. He said, "Have you ever thought about writing a book about the garden?" I said, "No, until you mentioned it." I was trying to write this thing up for the garden tour. Anyway...

David

It's my fault.

Anne

Yeah. Anyway that was the beginning of looking at how soils function and what makes them function normally and what makes them function abnormally. It led us both to look into the science and history around farming and agriculture. Dave had covered some in Dirt. But it also led us to this new area of science, which was just exploding at this time, around 2015, 2016. Research was coming out about the human microbiome, not so much the soil microbiome, because plant people had known about microbes and their beneficial relationships with plants for quite a long time. All this research exploded, telling us that the microbiomes, especially the communities in the human gut, were intimately involved with human health and well-being.

We looked into science and history around also human health and microbes. This led to some cool stories in The Hidden Half of Nature, about Louis Pasteur and Robert Koch and this amazing woman biologist, Lynn Margulis, who was onto the whole microbial story before others. The long and the short of it is, we came to see parallels between the soil the human gut, in particular about acquiring and processing nutrients and these co-evolved symbiotic relationships and how the tiniest creatures on Earth were absolutely essential to the health of plants and people.

That was the story in The Hidden Half. Then Dave took it deeper with Growing A Revolution.

David

One thing we noticed in writing The Hidden Half was that life came back to the yard as a result of all the composting and organic matter addition that Anne was doing, her regenerative gardening practices. The color of the soil changed from khaki to a rich black kind of... what we might intuit as fertile soil. The organic matter content went from a couple percent up to almost 10% in the yard. We saw huge changes in our yard.

Having written Dirt and then seeing the changes in our yard we asked, "Could we do this on farms? Could agriculture do the same thing and still grow enough food to feed everybody?" That’s the question that we started to dive into with Growing a Revolution. The way to do that was to visit farmers who had done to their farms what Anne had done to our yard. I’d met Gabe Brown and other farmers at some conferences. When I wrote Dirt, I started getting invitations to go speak to farming conferences about the history of erosion. That’s where I started meeting regenerative farmers.

I took literally about a six-month period and started traveling around the world to visit farmers who had done this across the American Midwest and Equatorial Africa and Central America up into Saskatchewan in Canada. (Not quite our 51st state yet, I guess. Sadly)

I started to realize that there is a common set of principles that can work to rebuild soil fertility remarkably fast, at least as geologists measure time. That those principles worked on small subsistence farms in Africa and Central America and large industrialized farms across North America. Of course the practices were different. The technologies were different, the crops were different, the climate was different, the soils were different. But the general principles that rebuild soil health seem to be universal and generalizable.

That became the theme of that book, how can we look at farming in a way to build soil health? There are two types of soil disturbance that contribute to the degradation of land over the long run. One is tillage, plowing that leaves the ground vulnerable to erosion by wind or rain. If you're losing the soil itself, you're losing its fertility because the top soil is on top and that's where the erosion happens, you lose the best stuff first. Then the degradation of soil organic matter is what feeds the microbes that Anne and I were writing about in Hidden Half of Nature. These pieces all started coming together in thinking about how regenerative farming practices that can turn the long term degradation that past societies have imparted to their land around?

It boils down to:

• Minimize physical and chemical disturbance
• Keep the ground covered with plants that have living roots to put exudates into the soil, they will exude organic compounds and to feed their microbial allies that we were writing about in Hidden Half.
• A diversity of crops, whether in a rotation or all at once in a field in a glorious cacophonous mess that supports communities of organisms in the soil that can partner with plants to enhance their ability to take up mineral micronutrients, to make phytochemicals, bolsters their health and defense systems and serves as organic fertilizers.

Growing A Revolution is what led us to realize that there is a style of farming that can do to the world's farms what Anne did to our yard. It's loosely termed regenerative farming, but it boils down to practices that build soil health.

There's lots of ways to do that. There's not a simple recipe, but when you think about what takes to cultivate beneficial organisms in the soil, you need to stop disturbing them, you need to feed them, and you need to give them partners to play with. That boils down to no-till cover crops and diverse rotations.

Then we had questions about what this all meant for human health. I'll let Anne describe how we got into doing What Your Food Ate.

Anne

Some people ask us with regard to What Your Food Ate, the most recent book, “why didn't you write this book first? This just all seems so obvious.” It is obvious, but we didn’t see how obvious it was until we finished the preceding books.

David

I think that good ideas are those that in hindsight seem obvious.

Anne

Exactly. We call them “The Dirt Trilogy,” meaning that What Your Food Ate rests on the other three. All we had learned about microbiomes, about the importance of organic matter, about those practices that Dave just mentioned, it all led to the big question, what does this all mean for the plant and animal foods in the human diet? Do they have what they're supposed to have in them? The things that are not supposed to be in these foods, are they there or not? how come?

What Your Food Ate was an exploration of how farming practices affect food. We started with soil and soil health, at how that ripples into crop health, animal health, and then human health. This is all backed up by the research we did for What Your Food Ate, which is the most intensely researched of all the books. It’s hard to go straight from soil health to human health. It’s a puzzle, you've got to assemble your pieces and find how they fit together and then build the big picture. There seemed to be a group of things that farming practices profoundly influence that need to be in plant and animal foods of the human diet. We call these things the Fab Four.

First, micronutrients. This isn't anything new. People have known about micronutrients for a long time. It's all these mineral elements, copper, zinc, iron, that we need them in very small amounts in our diet, but they have an outsized effect in terms of their volume and density in our foods.

Then phytochemicals. This is where science is interesting. The history of many fields becomes like a ball and chain around that field. I would say in the field of nutrition, one of the chains is thinking about nutrients purely in terms of calories, the ceaseless endless harping on fats, carbohydrates, and proteins. Because when you consider phytochemicals, naturally produced plant compounds, they don't have any caloric value. What they do have though, is huge disease prevention value. Phytochemicals are hugely influenced by farming practices. There's all kinds of science, all kinds of research across the biomedical sciences that show us why phytochemicals are important and how they integrate with human biology.

Then there’s fat balance. Fats simultaneously are the best kid on the block and the worst kid on the block. It comes down to the types of fats and their proportion in the diet. One of the most researched areas is omega-6 and omega-3 fats. We go into that in quite a bit of detail in the book.

The fourth of the Fab Four is this whole new area, not acknowledged in nutritional science: microbial metabolites. This is everything that the crop microbiome, all these microbiota, bacteria, fungi, viruses, all kinds of things in the soil, they're consuming this organic matter or they're consuming plant exudates and they're transforming their food, the microbial diet, either directly or indirectly into other things that either the crop takes back up, or in the case of humans, our gut microbiota are making microbial metabolites based on what we're eating. Human cells can then take up these microbial metabolites. One way or another, the fab four, the micronutrients, fat balance, the phytochemicals and the microbial metabolites are all influenced by farming practices.

Here's a kicker. You cannot get sufficient amounts in the right proportion of the Fab Four in any other place except foods of the human diet, plant and animal. Yeah, there's supplements in a bottle, but we know they're never ever the same as how they come in a whole plant or animal food. So the big takeaway with What Your Food Ate was, here's all of these things that farming affects that are in the human diet that get into our bodies and the diet is the only place to get them. This is why farming matters for human health.

David

Or how one farms. Because we were able to show that the Fab Four are all things that farming practices impact. It turns out that regenerative farming practices, that suite of practices we were talking about earlier have a positive effect, whereas conventional practices have a negative effect.

Anne

In essence, these regen techniques work to suffuse our plant and animal foods with all of the nutrients, the writ large definition of nutrients with what is supposed to be in them. This is largely modulated, facilitated by microbiomes. The microbial world is not just a disease-ridden horrible place. We need these communities of microbes in the soil and in our bodies.

Jesse

Awesome. I'd like to dig a little bit into microbiology in the soil and have you explain the different functions that the microbes are doing, but I just want to give Natalie a chance if you have any questions or if you want to jump in at all before you move into that.

Natalie

The only thing I’d ask for clarification on is what you mean by “regenerative practices,” because that's so broad. Sometimes regenerative practices is just no till. I'm curious if that is enough to move the needle, or if there's specific regenerative practices that we need to look deeper into and include.

David

There's a lot of debate about just what constitutes regenerative agriculture. It’s a term that hasn't probably been adequately defined in common usage Some people say if you just go no-till it's regenerative. Well, I'm sorry, but that's not true. There’s lots of studies that back that up.

What I found in writing Growing a Revolution was that it’s a combination of minimal or no till, minimizing chemical and physical disturbance, along with keeping the ground protected from erosion and covered with cover crops when you weren't growing a cash crop to produce more exudates, as well as a diversity of crops, which translates into different microbial communities in the soil. It was the combination of those three that catalyzed rapid rebuilding of soil fertility.

One of the things I also learned through writing Growing a Revolution was that livestock can be an accelerant for soil building. Now I had shown in my PhD research that livestock can degrade land. There's plenty of examples of how poor grazing practices have degraded land around the world. But it was an eye opener to me to visit branches where cattle were being employed to regenerate soil fertility. It's a different style of grazing, just like the different style of cropping can be regenerative. I tend to think of regenerative practices now as a big umbrella that covers suites of soil building farming practices. Biodynamic agriculture, that's regenerative, agroecology is regenerative, regenerative organic is regenerative.

But just going no-till is not necessarily regenerative. If you’re using a lot of herbicides in no-till, well, you're cutting erosion way down. That's a good start. It's a down payment. It's not achieving a regenerative style of agriculture. It's preventing the loss of the soil itself, but it's not doing that much to rebuild the biology.

A loose definition would be practices that build soil health. I like that because no two farms are the same. Not every farmer is going to be growing the same crops and they'll have different equipment and they'll be selling into a different market. Rotations or cover crops need to be tailored for the farm. But if we think of building soil health as the definitive aspect of what we call regenerative farming, we can use to navigate, okay, what is and what isn't.

Natalie

Love it. Thank you.

Jesse

The key to building soil health would be, do you have a functional soil ecosystem, correct? That’s measurable and you can gauge whether what you're doing is achieving that result.

David

Well, you'll have an ecosystem in the soil no matter what you do, but it's just like a vacant lot in the middle of a city. It’s an ecosystem, just a crappy one. If you have a soil ecosystem that's working for the farmer, working with to support the health and vitality and production of crops, that's the soil ecosystem you want. The big lesson we took from watching and transforming our garden is that we started out with crap soil. We ended up with rich fertile soil that enabled the plants to achieve their full potential.

When we think about regenerative farming, think about feeding the soil to generate that healthy ecosystem that will then go to put trillions of little farm hands to work for the farmer, trying to support yields and the health of the crops.

Anne

Yeah, it’s clear to anybody with a newborn or an infant that as a person moves through various stages of development, diet is hugely important to normal growth and development. Yet when it comes to plants, we throw that out the window. With livestock, we think, eh, can't matter that much. But defensive systems, immune systems, ability to do all kinds of things is so dependent on what are plants and animals eating. That's in part why we titled the latest book, What Your Food Ate, not You Are What You Eat. We’re trying to make the point that what we're choosing to feed crops and livestock that become a part of a human diet is foundational to our health. It's what your food ate. It is the beginning of the ripple effect on up into us.

David

Yeah, we got to take that old adage one step back.

Anne

Or one step ahead, depending on how you think about it.

Jesse

To unpack what the microbes are doing down there, let's start with the whole plant health side. What are the microbes doing to make the plants healthy? What do the symbiotic relationships look like? What do the plants contribute to the microbes and what are the microbes giving them in exchange? You've talked a bit about this already, but maybe a couple specific examples of how that passes on all the way to human health.

Anne

Here's what's the bottom line on all of that. Everybody wants to eat and everybody needs to eat. In the botanical world, this is where all these exudates come in. Plants have a monopoly on sunshine. They can gin up just about anything based on the energy that they acquired through photosynthesis. They’re stuck in place, and they rely on chemicals and compounds, so they make nutritious exudates. People often talk about exudates as just carbohydrates. I think that's human centric related to sugar and getting energy. Certainly carbohydrates are a part of exudates, but there's also fats in exudates. There's also proteins and biochemicals in exudates. We have the full buffet for the plant microbiome. When a microbiome is well fed, you get robust, accurate communication between a plant host and its microbiome. You get microbiomes that are never malnourished. They're not going to start looking around for some other plant to start up in association with. You want the relationship between microbiota and host, plant, animal, or human, to be tight. You don't want somebody wandering off because as soon as these microbes wander off or die, the host is sitting there with half a defense system. The immune system stuck inside the host body, all of a sudden lacks important information that microbes previously brought to it. Information like, I'm detecting a pathogenic virus or a pathogenic fungus here on the approach or already inside your cells. Time to tee up the immune system to kick that pathogen out.

When things begin to break down through lack of nourishment for these microbiomes, the communication starts to falter, then all the various cellular pathways involved in a normal immune response start to falter. What was a solid house becomes more like a house of cards, and you knock one card out and another one falls, and it becomes a little heap, flat on the ground and dysfunctional.

That's the big picture. There are lots of little details of the actual compounds being exchanged and what happens when they're missing or there's a little chemical. That is endless fodder for learning more about and investigating this tight linkage between hosts and their microbiomes.

David

Yeah. a lot of it boils down to nutrient acquisition and then chemical signaling and defensive mechanisms.

Anne

One interesting thing about all these relationships and communication, chemical and otherwise, is that biologists used to think, wow, evolution, that's about knocking heads. It’s about high level predators chasing prey around. The cheetah that runs the fastest is the one that's going to persist in the population. We’re going to get ever faster cheetahs.

That's certainly one part of evolution, but what has been entirely overlooked is, how is a single celled organism like a bacterium ever going to survive on this planet by their lone tiny little body? They're not. They would perish were it not for starting up developing and hanging on to symbiotic relationships with hosts. These are ancient relationships between life forms, not just microbes, but also larger life forms, bees and flowers and things like that. We know that these cooperative, mutually beneficial relationships are as much a driver of evolution as head-on conflicts. Biologists are quick to point out, oh yeah, symbioses are just any close association. That's true, it's any close association, even between a parasite and a host. But we've largely overlooked the power of these mutually beneficial relationships, and helping the microbes survive along with their host; you remove one, and the other just falls apart.

David

If you go back far enough in geologic history, partnerships with microbes are what allowed plants to colonize the continents. These are ancient, deeply embedded and evolutionary trajectories for most of the organisms we know. The cooperative elements of symbiosis, the mutualisms, are things that microbiomes developed in association with their host organisms, whether it's plants or people or water buffalo or whatever. One of the things that I've learned through this whole journey in writing these books is that cooperation can be remarkably competitive.

I don't know why that should be a big surprise. Look at human societies. We live in villages and cities. We all have different jobs. There's lots of analogies one could make, but I think it's only recently that we started to think that maybe this is another root level evolutionary process in the natural world that we've overlooked for a long time. But it's the way that microbial relationships with host organisms, for the most part seem to work. Then you get a pandemic and the bad actors come into play, but the bad actors shouldn't make us ignore the, the broader structure.

Anne

This is part of the challenge. Our human brain loves to think in terms of black and white, but you find in the research that these communities of microbes are incompletely understood. We're finding these pathogen populations amidst what we know to be beneficial actors. This microbiome's got a little element of unhelpfulness, shall we call it, along with all these helpful components. How do we, how do we parse that?

The way I think about it is that plants, animals, people, every organism throughout the history of life has always lived shoulder to shoulder with some pest or pathogen. That is just a reality. But another reality is that you have a robust immune system. The human immune system, of course, is different than the plant immune system. But if you support that defensive system, and this is where microbiomes come in, there's some pests and pathogens, but they never reach fatal levels. You go on with your life, and they're always there, but you never let them get the leg up. If you can keep pest and pathogen populations suppressed to non-harmful levels, who cares if they're there? We're never going to obliterate every pest or pathogen. Life is way too vibrant and quick moving to ever kill off, say, all the corn rootworms.

David

Our efforts to do so simply make resistant pests. That's a whole other conversation.

Anne

Yeah. The other thing that writing these books has shown me is that soil life and the human body is incredibly dynamic. It's incredibly contextual. It’s very nimble and agile, and there's lots of feedbacks. A pivot this way means a pivot that way. This whole milieu is very quick-moving and it's the job of the farmer, the gardener, the eater, to honor that fundamental property in ways that always keep you, the host, on top of it all. That it never gets so imbalanced that you're turning a situation around that is negative for you.

Jesse

I think of three pillars, if you will, of what the microbial community is doing in the soil. The health component: plant health, crop health, animal health, human health that follows through linkage. Another is the soil structure, microbes building soil structure to make soils more resistant to erosion and these other detrimental things. Could you explain a bit how the microbes build the soil and the implications of that has?

David

Yeah, when you look at soil structure, you're talking about how the pieces of the soil are related to each other. It’s what creates the glue that can get pieces of the soil to combine into what are called aggregates. It turns out that fungi play a huge role there in many soil systems. We go into how they do it, but they're there, they exude compounds that work to do that. Then their dead bodies turn into a whole lot of organic matter in the soil. A soil rich in organic matter can hold more water than a soil lower in organic matter. It helps if there are void spaces that allow that water to move around and to sink down into the soil when it rains instead of running off over the surface. That’s where tillage plays a big role in degrading soil structure. If you want a soil that's structured to have a bunch of organic matter and void spaces, the way you get that is by having these aggregates that hold their shape so water can move down in between them.

Life is what plays a dominant role in creating those structures. What happens when a plow comes through? It turns it all up it cuts up, cuts the void spaces open, it slices the hyphae of the fungi and it can powder the surface layer of the soil. Then the next time it rains, that crusts up and the rain runs off over the surface instead of seeping down to where the roots are where, they can do good for the farmer and the crop.

Soil structure is one of those elements of soil quality that plays into soil health. There's different kinds of structures and different soils around the world. You wouldn't expect to see the soil structures in, say, a vertisol in a California grassland or an oxosol down in Brazil, it’s very contextually dependent. But life in the soil, both the microbial and the macro in terms of worms and dung beetles and all those other kinds of things that are down there doing their thing. It's life that helps to structure soils in ways that facilitate the growth of plants. It's a whole next level of mutualism if you look at community organization.

Anne

And on the topic of soil aggregates and getting good structure in soil, it's a microcosm of the regenerative practices that we've talked about before. All this aggregation is a consequence of microbiomes that are well fed. Well fed with crop exudates, well fed with physical organic matter. All of that is going to grow and support these microbial populations. like Dave just said,

Glomalin is the name of one of the compounds that mycorrhizal fungi make as a natural part of their biology. This glomalin has a huge role in good soil aggregation. These microbes aren't down there thinking, “we need to work on soil aggregation down here, this is what this field needs.” No. All these microbes are doing is consuming organic matter. As a consequence of their consumption and metabolism of their preferred diet, the farmer, the gardener, the field reaps the benefit of nice soil structure that then delivers the secondary benefits Dave talked about, which is water distribution and storage of water in the soil. It’s something I’m reminded of daily when I hear about these wild thunderstorms and flash floods happening in the South and mid-Atlantic state. These regen practices, they just start to pile on positive consequences. As a gardener, as a hands-on person, if I can find one or two things and let them have at it, and I get 10 to 15 other things that I don't have to lift a finger to do, I'm all in favor of that process, right? We're all looking to save labor and time. You do a few fundamental things and let it rip. and you can stand back and go, I like that, I like that. Now I have time to go think up something else to do or maybe take a break and sit down.

David

Or think of something for me to do.

Anne

Yeah,

Jesse

Good. When I first got into this, the concept that soil structure can help make the land resilient to both flooding and drought, the two extremes at the same time. It's one of these mind-bending moments that like you were saying earlier, it's so obvious once you think about it, but it's not necessarily obvious when you say, over here these farmers are dealing with too much water and it just runs off, over here they don't have enough and it dries out. The same thing is the solution for both.

David

Yeah, and it's a little counterintuitive, right? Because we think that if you're plowing, you're breaking the surface up. Shouldn't that let water seep down into the soil? Well, if you think about it that shallowly, yes. It took a while for people to figure out that that wasn't what was going on in most soils, and that it was counterproductive in terms of getting water down into the root zone of plants. Our understanding of how the system works colors how we think about how our manipulations of it should pan out, and if we have the wrong model in mind, we're going to get the wrong result.

Jesse

The soil structure, that's also important for the airflow within the soil too, correct?

Anne

Yeah, for sure. And we know about a lot of soil diseases, the conditions, the habitat that some of these soil dwelling pathogens prefer. They like anaerobic, they like low oxygen levels. Good soil aggregation keeps air moving through and part of the game of anything really. This is fundamental, you want to optimize habitat conditions for the species that you desire or that you want, right? Why in the heck would we make conditions hospitable for pathogens whether in the human body or the soil? We have enough of that going on in the human world already. I we take what we know about what conditions beneficial organisms in the soil and the body thrive under, those are the conditions we need in farming and in the human diet.

Jesse

Great. Then the third pillar of soil health is what Dr. Elaine Ingham famously described as the soil food web, and the idea that even looking beyond the food production, but almost on an ecological level, that biodiversity is driven from the ground up, from the smallest members up. Could you describe how that plays out in the soil?

David

Well, an interesting thing that has been uncovered relatively recently is that in a lot of soils, the majority of organic matter is from dead microbes. You can think of the soil as nature's recycling system where you're taking dead stuff and turning it back into the raw materials to grow new stuff. Then the plants also photosynthesize and rocks break down and so forth. There's this big wheel that's turning, and it's a diversity of organisms that helps spin that wheel. Thinking about all the symbioses between microbial life in the soil and plants, if some random seed drops in a field somewhere, what are the odds it's going to have its best friend partner sitting right where it landed? The odds go up if you have a diversity of life in the soil, the number of potential allies that any particular plant or crop will have will increase. If we buy the idea that partnerships with soil life are important for plant health and opt for a style of farming that minimizes the use of agrochemicals and disturbance, then the diversity of organisms in the soil that helps drive those connections and that allows them to be manifest.

We saw in our own yard, the life came back in the order of evolution on Earth, from microbes to crawly things and mites in the soil to worms and then the birds that ate the worms and the eagles that ate the baby crows, we essentially assembled an ecosystem from scratch from feeding the microbes. There is an element of “build it and they will come” to the rippling of soil biodiversity to biodiversity above ground. But there's a whole bunch of other crap that we do above ground too that's going to influence that as well, obviously.

Anne

Yeah, I’m glad you brought up Elaine because if you've heard Elaine talk, often we hear fungi, bacteria, nematodes and protozoans, right? Those are the four major groups she goes to when she talks about the soil food web. The soil food web is like the grand supply chain of life. We've got consumers of organic matter, they're getting what energy they need out of that. They're then excreting waste products, which is somebody else’s first rate dinner. Then they're consuming that and they're excreting something which is somebody else's first rate dinner. This is a supply chain of nutrient acquisition that's based on nutrient transformation.

In biology, we often think about plant life being the foundation for animals and especially for herbivores. All they do is eat plants and then you get a nice population of herbivores and then the cheetahs and all the carnivores. With the soil food web, it's not exactly herbivores and carnivores, but it's certainly these predator prey relationships. Thinking back to COVID days, boy, did we ever learn about what happens when you start jamming monkey wrenches into the supply chain, right? Stuff goes flying off left and right, whole businesses get shut down. This is why keeping that supply chain in the soil well fed, moving along, everybody's getting what they need is like the insurance policy on soil health, crop health, animal health, and human health. When everybody is getting what they need, everybody thrives. You take out a piece of the supply chain, and then you've turned this wonderful, beautiful, robust system again into a house of cards that just begins to unravel and the problems start popping out everywhere.

Jesse

You've done a ton of academic research, gained firsthand experience, and traveled the globe, seeing the results of farming for soil health. What do you think is most convincing for someone who's skeptical or needs to understand soil health better before believing in it? You have the case studies, you have your own experience, you have the research obviously a blend of all three.

David

What got me to realize that prioritizing building soil health was the way we need to go in farming, was visiting farmers around the world who had already done that on a wide range of different kinds of farms, from subsistence farms to huge ranches and spreads in the American Midwest. They used different practices, but the same guiding principles of minimizing chemical and physical disturbance, maximizing the ground cover and maximizing the diversity of the crops, whether in a rotation or all at once, whether or not they introduced livestock and regenerative grazing practices to accelerate soil building, not just practice, but the combination of all of them. It convinced me that this was a recipe for rebuilding soil health and soil fertility, and that soil life was the key to it.

And what convinced me that this could catch on was that all those regenerative farmers I visited in writing Growing a Revolution were more profitable than their conventional neighbors. That's what turned me into an optimist on this, because farming systems that don't sustain the farm are not going to be sustainable.

What made those regenerative farmers more profitable than their neighbors? They were spending less on fertilizer, they were spending less on diesel, they were spending less on pesticides. Why? Because they didn't need them anymore. They weren't driving their tractors as much because they went no till for the most part or low till.

Their pest pressure was much lower than their conventional neighbors. After a transition period of one to three years, their crop yields got back to those of their conventional neighbors. Some studies of organic farming that show similar things, where the longer one stays in organic relative to conventional, the so called yield gap starts to close as soil health comes back.

We have something here that is both environmentally and economically attractive. When you get those two things working in parallel, it's the recipe for rapid change and adoption. I’m a geologist, so I view rapid changes as, over the next couple decades, we might be able to convert conventional farming to a more regenerative framework. But I've seen changes in the soils on farms within a year or two. After 10 years, it can be radical in terms of regeneration of fertility.

Anne

I'm a person who loves visual, physical proof, something I can put my hands on and go, this is better, or this is worse, right? We've all had failures in the kitchen. You just want to get rid of those, right? But we've also had these grand successes. You sit down to eat it, or you can just sense it as you're cooking like this is going to work out. What has convinced me has been in my own gardening adventures. When I see somebody else's garden, I usually keep my thoughts to myself if, I'm not saying great stuff. But the number one clue for me is the vibrancy and the vitality of the plants that I'm looking at and that I'm moving through.

For example, I shop a lot at our, at our local farmer's market. There's nobody checking how these farmers are growing their stuff. Some people have signs up that say it's organic, some people have no signs and so on. I can usually take a look at whatever is for sale and get a sense of what these practices are on a given farm. I'll usually see a little bit of stress, not huge stress that makes you run the other direction from the food, but something. Then there's this one farmer that showed up recently and their stuff looks perfect. I'm like, that is not real. I don't know what those folks are doing, but I'm sensing use of something that might not be great for the soil microbiome when I see this pristine looking stuff.

The eye can trick you. We think, that looks beautiful. I'm going to get that. But once you get an eye for what has built the vitality and vibrancy of what you're about to eat, I angle more toward something maybe with just a little bit of evidence of pests pushed off the plant. When plants are healthy, that means I do less as a gardener. I'm not fretting. I'm not thinking, what more can I do here? I need to intervene. I need some a treatment here.

Convincing others, that can be a hard sell, especially in these days with how prolific misinformation is. You’re always going to have a segment of the population that no matter what, they're just not going to be with you. So what I like to think about is the part of the population still has an open mind. They have some skepticism, but they're open to new information. Instead of bombarding them with information, those people want to see stuff that's real.

When it comes to farmers, one of the things that's hugely beneficial and that I've learned a lot from are farm schools. You have farmers that are doing practices that have achieved the results that can come from regenerative practices. Farmers are famous for “show me what you got, what does this look like on the ground, you can talk all you want, but till I see it in the field, I'm not buying it.” These gatherings of farmers doing education and communication about their own experiences is one of the most compelling ways of sharing with others what is possible with regenerative practices.

Jesse

Fantastic. I love how all those different things play off each other. It must have been tremendously gratifying for you to do the research and realize that the science points in the same direction as what you were seeing.

David

That was one thing that's been very convincing for me. Writing What's Your Food Ate, I believe that we read 1000 peer reviewed articles to draw from. Our modus operandi in writing the books is to combine our own experience with historical analysis, but also to dig deep into the peer reviewed literature, what studies say about these things, and then weave it all back together. But as Anne was saying, the most convincing thing is when you see a farm that has healthy thriving soil and crops, especially if you have an example, either next door in a corner that hasn't been treated in the same way, and you can look at the soils and see the difference. That's convincing.

Anne

I remember for What Your Food Ate, we went we visited two regenerative vegetable farms, one on the East Coast, one on the West Coast. The East Coast one was in early June. It was a drizzly day. The light across the fields was absolutely stunning. Not only being able to see the plants in non-glary light, but also, you could get the full sweep of the diversity of crops growing out there. There must have been 10 or 15 different things. You’d have some cabbages next to some garlic next to these beds of kale that looked like something out of a dinosaur movie. Everything signaled health and fecundity and vibrancy. And that all added all up to me for health.

The West Coast farm on the other hand, oh my god, it was in the 90s. I was looking out across Singing Frogs Farm, getting that the same sense as this other farm. Seeing all of these different crops, tomatoes, and even cauliflower that is not known as a hot weather crop, I couild tell that these plants are holding their own despite the stress of the heat. They had tomatoes trellised in two-dimensional rows to use space efficiently. The trellising on those tomatoes was part of the whole beauty and productivity. I see those kinds of things and I'm blown away by the potential of plants when we give them half a chance to be a plant and exercise their potential with their below ground systems and their above ground plant parts. That to me is rewarding and convincing.

Jesse

Awesome. Last question, you have these four books here. It's been a while since the last one came out, a few years at least. Do you have plans for any more to add to the library?

David

Yeah, actually, I've just sent the manuscript off for a new book that's provisionally entitled Regen, and it's about, you guessed it, regenerative agriculture. It's trying to synthesize what we've learned in writing the four that you've got in your desk into a shorter book that's equally well supported by academic research. There are hundreds of references in the back of the book.

It makes the case for prioritizing building soil health in agriculture across the board, whether you're an organic farmer or a conventional farmer. Making regenerative soil building practices the norm rather than the exception in agriculture is where we need to go this century. I'm confident we can do it. I've seen farmers who have done it and been very successful. There's no simple easy button for it, but there is a philosophy and there are principles that one can use to devise practices tailored to one's farm or garden, which will leave the land better off and the farmer better off economically. I'm optimistic that these ideas will catch on, because they seem to work.

There are large impediments in terms of how agriculture as a system is structured nationally and internationally. There are large organizations that make their living, selling conventional fertilizers to farmers. That's a huge business. You can't expect them to lead the charge for change if the change will reduce the use of their products. But I'm optimistic that it will catch on, because it seems to work.

Now, I've seen a few failures, but one thing that characterizes the successful regenerative farmers is that they're tinkerers. They figure out what will work on their farm, and it's not necessarily going to be what worked on somebody else's farm. Being curious and innovative pays dividends in this regard. But I think that the bulk of farming will come along over time, because we need to wean ourselves off fossil fuels this century, and that runs the agrochemical business today.

We need different ways of thinking about farming, and there's good examples out there to follow. I think building, prioritizing building soil health is the way to go. In the new book I make the case why that should be viewed as the future of agriculture. It’s not an argument for going back to medieval practices. It's about integrating the ancient wisdom of things like cover crops and crop diversity and crop rotations with modern science that allows us to build no-till tractors and to think about more interesting rotations and microbial inoculants to kickstart the biology in degrade soils. There's lots of things that we can do to innovate around rebuilding soil health, but that needs to become the new North Star of agriculture, in my opinion.

Anne

I’m going to ask us a question right here. How come we didn't start with this book? How come we started with Dirt? Really, if soils had a voice, and we're writing their story, that’s Dirt. They're saying, mistreatment and degradation has been going on and on and on. I'm excited about this new book, because I think it's I think it's soils finding their voice again. Writing the story in a way that we humans begin to see that it's up to us. It's the call for a new ethos and a new way of thinking.

You'll often hear at farming events that he biggest problem with the transition to regen is not my equipment, it's not the soil, it's what's between my ears. In other words, it's how we think about soil. I'm excited. I think the soil health movement is out of the bag. We want to push that along and suggest that it’s time for a shift in how we think, because as soon as you shift your thinking, practices begin to line up with the shift in thinking.

David

That’s a good summary of the new book.

There are times when paradigms get overthrown and shifted. I think that in agriculture, enough science connecting microbial ecology and soil ecology to what we want out of farms has come to fruition. Now it's time to reconsider our our overall operating framework. yeah, that would involve thinking differently about the soil, having a new philosophy of farming that prioritizes soil health as the goal.

Anne

I want to put a plug in right now for compost extracts based on my personal experience. This isn't some long-running experiment, but I will tell you this. When I started the garden at our first home, and remember the soil was bad, the plants are suffering. Roses are notorious for this fungal disease called black spot. It looks just like what it sounds like, these black spots appearing, circles all over the leaves and you go, oh crap, I think that's black spot. The leaves eventually die and drop off, and that's not any good because you're getting this black spot into the soil. So I was playing around with a compost brewing system that I had at the time. I also had a worm compost bin and I thought, what the heck? I'm going to give this a try and see what happens. I'm digging through my worm compost bin. I'm filling up the sock type thing with that worm compost. I've let the water dechlorinate in the five-gallon bucket and I put the nutrient solution in and the aerator. All this foam is coming bubbling up. It smells nice. It's just a lot of fun. It's in the summertime. It's outside in the garage. Who cares that it overflowed and I brew it up. I had this wonderful sprayer. It's a trombone style sprayer that I got from England, because of course they have these things that they've been using for a long time. It’s a hand pump thing with these beautiful brass fittings and stuff like that. I'm like, “okay, black spot, here we go.” I drenched that with my compost tea. I sprayed out five gallons of stuff on various other plants that my gardener's heart tells me aren’t looking good.

Within two or three days, the black spot is clearing up on these roses. I'm like, wow, that is pretty cool. I continue doing this with the roses over that summer and the black spot is virtually gone. Then of course I got lazy. I stopped using the compost extract. Guess what comes back? The black spot. It was a way for me to see that, wow, this one thing that I'm doing has improved this situation. Now, do I know exactly why? I don't, but whatever was happening there was controlling a pathogen. It wasn't gonna kill the roses, but boy, did they look crappy, and there's nothing a gardener hates more than a crappy looking plant. I'm not growing corn, corn after corn after corn. You've seen one corn, you've seen them all. You got a few plants that look dumpy and it's like the whole garden looks dumpy. I'm not into that. I want healthy plants, and there was something in my compost brew that was doing the trick there.

Natalie

That's amazing.

Jesse

Cool stuff. Thanks so much for your time with us this afternoon, and thank you very much for your contribution to this field. It's making a big difference to have, um, to have these, these well-researched, well-written books.

Anne

Well, that's our aim. Good.