Podcasts

Uncovering the Science Inside Your Soil w/ Dr. Kris Nichols, PhD

Interview with Kris Nichols, Director of Research and Extension at Canadian Organic Growers and Research Director at MyLand Company

Show Notes


What is really going on in your soil? This week, we take a deep dive into the science of soil microbiology, with Dr. Kris Nichols. Kris is a soil microbiologist who holds research positions at Canadian Organic Growers and the Arizona-based MyLand Company. She joins Organics Unpacked to break down the complex activity of soil microorganisms and how that relates to carbon — and what that means for organic growers.

Learn more about Canadian Organic Growers: www.cog.ca

Learn more about MyLand: www.myland.ag

Connect with our guest on LinkedIn

#OrganicFarming

Podcast Transcription


INTRO: Welcome to Organics Unpacked, a podcast for the business-minded organic grower — an interview podcast where we hear from the top experts in the commercial organic industry, with a focus on the business elements of organic growing both in and out of the field. You will gain insight and grow your operation. This show is brought to you ad-free by Avé Organics, a Wilbur-Ellis company. To learn more about Avé Organics, visit our program notes. In the meantime, enjoy the show. 

TOM: Hello, everyone. Thanks for tuning in today. Welcome to a new episode of Organics Unpacked, a podcast where we discuss organic farming from a practical perspective. I’m your host, Tom Buman. Today, I’m joined by Kris Nichols. Kris is a soil microbiologist who has a lot of roles in her life. She is a busy person. Kris, welcome to Organics Unpacked.

KRIS: Thank you. I’m so happy to be here.

TOM: Well, we’re really excited to have you join us. The topics that you’re going to talk about today are really hot topics, Kris. I really cannot think about opening an ag magazine these days without talking about soil health and soil carbon and carbon credits and all this stuff. But before we get started with the information, can you give us a little background on how you got here today and what makes you qualified to be on today’s program?

KRIS: Well, thank you. Yeah, I grew up on a farm in southwestern Minnesota. So I come from an agricultural background. I have undergraduate degrees from the University of Minnesota in plant biology and genetics and cell biology, a master’s degree from West Virginia in environmental microbiology and a PhD in soil science from the University of Maryland. I spent almost 15 years working for the USDA Agricultural Research Service, both in Maryland and, then, most of that time I was in North Dakota for about 11 years. Then, I spent about three years with the Rodale Institute in Pennsylvania and then moved on to be doing some things independently. And that’s sort of what’s led to the roles that I currently have, the multiple roles that I currently have. I’m a Research Director with MyLand Company in Arizona and the Director of Research and Extension with Canadian Organic Growers. So I relocated from the United States this winter and now live up in Alberta, Canada. And I’m also doing some work here in Canada with the Food Water Wellness Foundation on carbon accrual measurements and monitoring and doing some other work with some growers with a carbon sink in Australia and a number of different other growers and organizations. So really focused on the idea of soil regeneration and utilizing carbon flows to do that.

TOM: Great. Well, there are two companies you talked about there, the Canadian Organics and MyLand. Tell me about your role in both of them and what the mission of those two organizations are. Why are they set up? What do they want to accomplish?

KRIS: So MyLand is located in Phoenix, Arizona, and it is basically using microalgae as an amendment. Primarily, in desert and arid and semi-arid environments, utilizing the microalgae as an amendment, that is going to help with water management, with some fertility management and doing that by working with the soil microbiome and growing organic matter in those soils. Then, with Canadian Organic Growers, that is an organization that represents organic farmers throughout the nation of Canada. And it’s focused on providing an advocacy role, an educational role and support and networking for organic producers, really trying to work on things like how we can build and increase the amount of regenerative organic production throughout Canada and really increasing the domestic supply of organic fruits and vegetables and nuts throughout Canada, as well.

TOM: So, Kris, you’ve worked in the U.S. and now Canada. Is there a difference between how they approach organics in crops, in techniques, in attitude? Give me the lowdown on the differences and similarities between the two countries.

KRIS: Well, there are a lot of similarities between the two countries as far as organic production is concerned and the focus on utilizing biologically-based tools in order to be able to address fertility and pest and disease issues. As far as the individual farmers and some of the tools that they put into place, there are a lot of similarities. Again, in Canada, just like in the U.S., it depends on where you are and what you’re growing. There are major grain growing regions in the Prairie Provinces like Alberta, where I’m at now, that are very similar to what happens in the northern Great Plains in the Dakotas and Montana. So you’ve got that area. You’ve got Ontario and parts of Manitoba that are a little bit more like Minnesota and Wisconsin somewhat, just a little bit getting into maybe the Iowa and Nebraska kind of similarities that you have there in Ontario. Then, as you go further east into Quebec and the Maritime provinces, those are more like the upper Northeast of the U.S., as far as organic agriculture. So not so much the Mid-Atlantic region, where I was with Rodale, but more in the Northeast. Some berry production — blueberry production — that’s there, wine growing regions and other things like that. Then, some of the more produce and fruit and vegetable crops types of things that they have in that area, so it does vary. 

Then, in the far west in British Columbia, that’s very similar to what you would have in Oregon and Washington. So it’s much like an extension of the U.S. from that standpoint. As you get up into the northern territories, it’s like areas in Alaska. So there are a lot of similarities as far as that’s concerned. From a policy standpoint, the Canadian organic standard does have some different policies, as far as that’s concerned, compared to the U.S. standard. There is reciprocity. So U.S. organic — the NOSB USDA certified organic — is the same in Canada as the Canadian organic because of the reciprocity. But there are some additional restrictions for the Canadian organic standard as far as that’s concerned. So, again, farming seems to be farming, and the line between the countries doesn’t really change that much. But, again, there are some policy differences. Just the way that the governmental and policy things are is a little bit different between the two countries. And just like in the U.S., the different provinces in Canada are very different from some of the different states that you have in the U.S., as well.

TOM: Sure. Well, thanks for that. So, getting into today’s topic: soil microbial, that soil health issue and everything. You and I talked previously that organic farming and regenerative agriculture have some differences but a lot of similarities. In your mind — I know we’ve kind of organized around organic farming and set standards for that. The term regenerative agriculture seems to almost include anything anymore, depending on who is actually describing it. But in your mind, tell us: how does organic — the terms organic and regenerative — fit together?

KRIS: Well, I think that they fit very well together. Regenerative, at its core, again, is this whole idea of regenerating the soil and bringing it back to life, working with the microbial communities, enhancing those biological activities and the functional roles that they’re going to provide. So, from the core of what organic has always been about, of soil and soil health, regenerative agriculture definitely fits in there. Now, when we talk about things with tools and practices, there are differences between. You have a regenerative organic approach, which utilizes, as you said, that organic as the baseline. So you’re not going to be utilizing the synthetic inputs that some of the regenerative non-organic or regenerative — it’s hard to know what to term it. It’s regenerative agriculture or regenerative conventional agriculture or regenerative non-organic. There are lots of different ways in which people talk about that. And from that standpoint, that agriculture is not eliminating the use of those synthetic inputs. So you can still use the synthetic pesticides and the synthetic fertilizers. A lot of what the regenerative non-organic agriculture focuses on is reducing tillage because they’ve seen, and we’ve seen with a lot of data showing, that tillage does have a negative impact on soil health and soil carbon and, in particular, in soil organic matter. 

When you do tillage, you can see a great release of soil carbon with those events. And that can have, then, a subsequent negative impact on biological activity. So a lot of the non-organic regenerative agriculture is no-till agriculture, and that’s one of the big, main sort of biological tool focuses that they have. Then, utilizing things like cover crops, integrating livestock and grazing management, utilizing companion cropping, double cropping, relay cropping, other types of plant management that they’re using as the way to add organic matter and to drive biological activities and utilizing those biologically-based processes. Whereas, with regenerative organic agriculture, regenerative organic agriculture is, again, sort of focusing on the elimination of the synthetic inputs and utilizing biologically-based inputs instead. So that really is looking at fertility and pest management in a different way with these more biologically-based tools and, then, the tillage. The biggest difference between the two is one uses synthetic inputs, and the other one utilizes tillage. So those are kind of the two tools that add a lot of controversy between those two practices. That doesn’t mean that there aren’t tools that cross between the two. The utilization of cover crops and different types of cropping combinations, integrating livestock into the system and utilizing other tools that allow you to do pest and disease management that aren’t synthetic chemicals or aren’t tillage are both being utilized by both camps, if you want to call them that. I think that, when we’re looking, again, farming is kind of farming on either side of the border when you’re talking about organic farming and those types of things. 

There are a lot of commonalities and similarities between regenerative agriculture and regenerative organic agriculture and lots of things that I think we can learn from each other. When I talk with regenerative non-organic producers, you want to utilize both of them. You want to utilize biologically-based tools as your first tools for fertility and pest and disease management. And for the regenerative non-organic producers, you have to eliminate the synthetic inputs because that’s negatively impacting the biological community. And for the organic producers, what can we do to find other tools that you could use rather than utilizing tillage? So, again, I think there are things we can learn from each other and many other things too. I would say, within regenerative, there is focus on some social aspects, community regeneration, helping to regrow small towns and regenerate those types of communities. And obviously, for everyone, there’s economic regeneration that we need to do both on the individual producer level, as well as the community. And also, one other thing that I would like to say is trying to provide more nutritionally-dense food. And I think that’s a big goal that everyone’s looking for. How we go about doing that is something we’re trying to figure out. But biologically-based tools, to me, is the way to go.

TOM: All right. So we’ll talk about that in a minute, but I’m kind of interested. Kris, you’ve got quite a background. So how did we get to this point in soil health? Like I said earlier, you can’t open up a magazine without talking about soil health. And I think, 10 years ago, I mean, there was some talk about it. And certainly, the organizations, businesses and agencies you work for talked about it, but how did we get to such a hot topic today?

KRIS: Well, I think there are multiple pathways that have been utilized to get there, but I think the biggest thing is some of the economic drivers. For producers across the board, the margins have become more and more slim. The ability to be able to make a living on land as a farmer has just become increasingly more difficult, and we’re combining that. So, as expenses go up, the price of land, the prices of equipment, the prices of various types of inputs, and then the fact that we haven’t seen the same level of inflation in the prices that you get when you are selling what you produce. That becomes where, again, the margins are very slim. So, economically for individual producers, part of the discussion with soil health was we need to find something else to help us be more economically viable. And that became part of the question. Then, in taking a look at what your plants need to be able to grow or what your animals need to be able to live, what is missing there? And what could you use that would be a low-cost tool to do that? It used to be on the conventional side where inputs were relatively inexpensive, and so we just increased the use of inputs. But you can’t really do that, and we’re seeing that those inputs aren’t able to address some of the issues that we’re starting to see. So what ends up happening is it’s become this combination of the costs of those inputs getting so high. But then, at the same time, the resilience of the commodities of the crops that you’re growing, of the animals that you’re raising, that resilience has started to decline.

So, when we’re seeing increased pressures because of climate issues, when we’re seeing increased pressures because of pests and diseases, new pests and diseases moving into areas as we expand globalization and are getting some pests and diseases coming from different areas of the world, it’s become much more challenging to be able to figure out how to manage the issues that you have. And when we’ve gone, in the past, to looking towards — especially on the conventional side of agriculture — to looking towards scientific tools and chemistry to solve those issues, we’re finding that chemistry can’t really do that for us. It’s the nature of biology. Chemistry works the way that chemistry works. I don’t dispute a chemist. If you do a chemical reaction, it’s going to do what you say it’s going to do. The issue is that, in the real world, in the outside world, not on a bench top, you’re living in a complex geological, physical, biological and chemical environment where all of those things — the physical structure of that environment, the porosity — all of those things are going to have an impact on the ability for the chemical reactions to occur. The geological aspects are going to do that. All of those things are going to impact how the chemistry works. So, in the past, we’ve just sort of gone and targeted chemical tools to alleviate the issues that we have. Everything has become far more complex, and it’s too difficult for the chemistry to override the physics, the geology and the biology that’s in that environment.

TOM: So it seems to me, maybe, organic farming has led the way in soil health issues, right? Because we’ve always believed in organic farming. We need to be putting that carbon into the soil. We need to be restoring the soil with either cover crops or manure or something that is really healthy for the soil. Then, we’ve been getting paid. I mean, typically, organic farmers are organic farmers because of the increase in premiums, but the inputs have not always been the cheapest, right? As you said before, sometimes in traditional agriculture, the inputs are cheaper. The chemistry was there. Do you see that changing as we start to understand organic farming more, that maybe there are solutions that become more cost-effective?

KRIS: Yeah, I do. I think that there are a couple of different things that can play a role in that. One is just as we’re growing organic, both in the U.S. and Canada — and as the number of producers that are utilizing organic tools and are transitioning to organic is growing — one of the things that will happen just automatically is things will get cheaper, just because of efficiencies of being able to transport and move various types of inputs around as the input industry grows. I mean, it’s sort of supply and demand. And once you get a greater demand, in order for that supply to meet that, the overall supply costs are going to start to go down because they need to be able to meet that expanding demand. And again, the efficiencies increase as far as transportation and production of those supplies and being able to move them around as we get more acreage. Many people know this. If you’re an organic farmer, and you’re in the middle of the Dakotas or in the middle of Alberta, and things have to be shipped several hundred miles, that is going to increase the cost. 

But if there are several of you there, that’s going to start reducing the cost. So that, overall, is going to be one of the ways that’s going to automatically start to reduce the costs. But the other thing is, again, as we’re driving towards utilizing more of these biologically-based tools, and the understanding of those tools and how to utilize them is improving, that also is going to reduce the costs of those tools. Because we’re now, again, utilizing them more at a greater scale, but we’re also understanding more about how those individual tools can act more efficiently. So, rather than always having to bring in inputs from outside, or off-farm inputs onto the organic farm, are there ways in which we can work more with cycling what is on the farm and increasing the efficiency of what you have there to actually reduce the costs of having to bring something in? And this goes, too, with our understanding of when we look now, especially, at biologically-based tools. They’re not just oftentimes addressing one individual need, but they’re addressing multiple needs. Yeah.

TOM: No, go ahead. I was going to say you said the word biological tools.’ Tell me what that means to you.

KRIS: So biological tools are, well, first, different types of microbial communities. In some cases, those could be, again, microbial communities that you’re bringing off-farm onto farm or generating on-farm, utilizing compost and compost teas, things like that. But more often than not, what I find to be really effective are the microorganisms that are already in those soils, so how to figure out how to stimulate their activities and get their populations to grow. So the other biologically-based tools are how we’re going to be managing plants and animals. So anything that’s living is sort of a biologically-based tool, and so you’ve got animals that you can bring in. And to me, animals doesn’t just mean livestock that you’re looking at. Animals can be insects. Animals can be birds and bats, and they can be wildlife, as well as your managed livestock. So all of those become biological tools because they’re living organisms, and they’re going to have an impact. We can help. 

We can work with how we’re going to be managing that. We could position bird houses and bat houses on our farmscape to be able to attract those animals. We can be positioning and growing different types of plants and plant combinations in shelter belt areas or in strips, even in our large grain fields, having strips of pollinator species, as well as not just attracting pollinators but also attracting predatory insects. Then, that’s going to help you. That’s also going to attract birds and bats. So you’ve got all of these things that are going to be mixing together everything. Again, looking at it from a biologically-based system, it’s also integrated, and you have all of these different, maybe, individual tools. But this is what’s going to reduce the overall cost. Those individual tools play multiple roles, and they usually are integrated with other tools that can be there. So bringing in different types of plants is going to be adding the biodiversity that you’re looking for in the system, which, again, is going to be attracting different animals of all scales, from microscopic to macroscopic.

TOM: So, Kris, as a bit of a skeptic, do you think that these biological tools are scalable? I mean, can we get them to the level that we’re affecting neighborhoods, townships, counties?

KRIS: Yes. I know that biologically-based tools are scalable. First off, we wouldn’t actually have soil if not for microscopic biological tools. So the fact that we have soil on land is the first thing to say it’s scalable. If we just had small pockets of soil, I would say you could have a good argument that it’s not scalable, but we’ve got a lot of soil on our land. That doesn’t mean that all of our land is suitable. Soil is different from just land. And I guess I should probably define this a little bit. Soil is organic. It’s carbon, hydrogen and oxygen — organic matter — bound to sand, silt and clay. Originally, when you had land, when earth was first forming, you had an aquatic environment, and you had a land environment. You had a non-aquatic environment. That land didn’t have soil. It was mineral rock. Even the sand, silt and clay that you have were bound up in a much tighter mineral matrix, rather than being broken down in the way that they have been. Now, over time, weathering — atmospheric conditions — will break down and weather that mineral rock down, to break it down into sand, silt and clay, into finer particles. But you don’t have soil until you have that organic component, that carbon, hydrogen and oxygen. And that happened because of the microbial communities, because they allowed for the continual breakdown of that mineral rock and the release of the nutrients that the plants — the pre-plants as they were — that would wash up on shore from the aquatic environment. 

Those algae or pre-algae — the bacteria, the photosynthetic bacteria — would wash up on shore, and you had to have this relationship with fungi and other bacteria that actually started to break down those minerals and release those nutrients. So the photosynthetic bacteria could actually get those nutrients to be able to, then, do more photosynthesis to make the enzymes, to do more photosynthesis to live and grow. So, starting off, because we have soil, I know we can do it at scale. Now, that took millions of years, and we don’t have millions of years. You have one growing season. So how do I know that this will work in one growing season is also when we’re looking at the idea of how the plants are going to be cycling and working with the microbial community to cycle various types of nutrients. So fertility is one of the big drivers that are involved in this. And one of the things that we found is there was a study. It actually came out in the early 2000s, so I know it’s old now. Hate to say these things. Makes you feel so old these days when you talk about: Oh, it was so old in the early 2000s.’ But in the early 2000s, there’s a study that came out by David Tilman, and it was on agricultural sustainability. And basically, what that study found was that one of the things they found in looking at fertility is that it takes more nitrogen today to produce a bushel of grain than it took in 1960

So it isn’t just looking at it. We’ve seen an increase in the use of synthetic fertilizers — especially synthetic nitrogen fertilizers, in particular — since World War II and, between World War II and World War I, the evolution of the Haber-Bosch process. But that has really gotten us to where we, on the conventional side, have added a lot of synthetic nitrogen to the system. And even though we’ve seen an increase in yield over time, we’ve seen a higher increase in the use of inputs, especially nitrogen inputs, than the increase in yield. So that’s why I’m saying on a per-bushel basis. And one of the things that we’ve always known, since we started utilizing synthetic fertilizers, is that the fertilizer use efficiencies are 50% or less, meaning that 50% or less of what you put on ends up getting into the crop plant. And this is, in particular, when we’re talking about synthetic nutrients or nutrients that are put on in the inorganic form. But in reality, thinking about this review that Tilman did — in reality, it’s probably always been that the nutrient use efficiencies have probably been, I would say, closer to about 20 to maybe 30%. But the microbial community compensated for that. 

TOM: By mineralization, right?

KRIS: Yes, exactly. And not just mineralization, but also transport. So you have things like the mycorrhizal fungi that act as a pipeline, connecting the plant themselves inside the plant roots and connecting that environment to outside in the soil where those nutrients get mineralized. 

TOM: What is that? Tell me what that is. Does that make it more efficient?

KRIS: It makes it more efficient because instead of having to — normally, the way that nutrients are going to move towards the roots is by mass flow. So they have to be dissolved in the water and move from the high concentration where they’re mineralized outside of their roots to the roots where there’s a lower concentration. So you get that diffusion gradient that gets set up. This is critical in a couple of different ways because, one, although there’s some intention involved in it, there isn’t a direct pipeline link. So the roots will create a diffusion gradient all around that rhizosphere environment, but your deposit of mineral nutrients may be over here. But you created, everywhere, a diffusion gradient all around the roots. So the efficiency of the diffusion gradient on the backside of the plant versus the efficiency on the front side is going to be very different because your mineral deposit is over here. So you have to be able to get that and utilize that in trying to get those nutrients to flow that way. Now, part of the issue that we run into is — again, the efficiencies of that diffusion gradient depend on where you are, where you create that gradient relative to where the pools are — since you don’t know where the pools are, there isn’t a good way of the plant being able to sense where the pools are. 

The plant has to create the gradient everywhere, and that decreases the efficiency on the part of the plant. When I’m talking about creating that gradient, it is about water because the plant — that rhizosphere — that’s your diffusion gradient. It’s an aqueous system that’s there. So when the plant typically has its highest nutrient demand is when the plant is starting to go through the reproductive cycle. It’s when the plant needs most of its nutrients. And we know this. We’ve done a number of different studies that have shown this, and people have worked on trying to figure out how you could apply. That’s why we do things, talking about foliar applications. We do things that are applying. And in organic, we do the same thing in utilizing organic nutrients that are going to break down slowly over time so they’re available to the plant when the plant needs them. So the plant has its highest nutrient demand, typically, especially in the Northern Hemisphere. This is when our soils are the driest. We get spring rain and fall precipitation, but we don’t get a lot in the middle of summer. So it’s hot and dry, which is going to increase the evaporation of moisture out of the soil. 

This is the time in which that diffusion gradient needs to be operating at its highest level of efficiency because you want to get those nutrients moving towards the roots. That is when the soil moisture is least. So, now, the roots are going to be required to actually give off more moisture, to try and create a greater diffusion gradient at that time. Let’s say you need to have a concentration of water that’s at a certain level to get the diffusion gradient going. If the soil moisture has been led out of the system, now the plant has to give off more exudates and more water to that soil environment to create the diffusion gradient. And this is the time in which, normally, these types of things would be translated into an increase in yield. Because you’re getting more nutrients, you should be able to do more. But the plant is having to give off more water in exudates, so the plant is now becoming what we see would be more drought stressed.

TOM: Not just because the water transpires and goes up, but also the water goes down and is pushed out to the root system to increase soil moisture, to increase absorption of nutrients. Okay?

KRIS: Right, yeah. So, basically, this is what was used to actually come up with our modern fertility requirements. Dr. William Albrecht did studies back in the 1950s, where he was looking at — and it was re-published in Acres Magazine called — The Drought Myth.’ And it was sort of a summary of some of the studies that he did. This was re-published in Acres, I believe, in 2000. It was either in 2000 or 2001. And the article was called The Drought Myth.’ And essentially, what he found back in the 1950s was that if you had fertilized corn, it used far less water and its yields were higher than if you had unfertilized corn. So, with unfertilized corn, you actually had to irrigate it and apply more water. So what he did was he did a study where he had a fertilized field and an unfertilized field. Then, he was able to use some irrigation to add additional water, and he added a lot more water to that. He irrigated a lot more of that unfertilized field. But even with that supplemental irrigation, in the end, he irrigated just to keep the plants alive. And by the time he went to harvest, his yields were far lower in that unfertilized field. So it took more water and had lower yield than where you added fertility. Again, this was done back in the 1950s, and this is what has led to our modern fertilizer industry. The idea was if you added fertility, you’d have a higher yield, and you’d use less water. 

Now, logically, that makes sense. But in Albrecht’s study, he was looking at synthetic fertility. But the reality is to the plant, fertility is fertility, whether the fertility comes from the producer having to apply some sort of nutrients, or it comes from the microbiome helping to provide that fertility. As long as it gets to the plant in the right forms at the right time, the plant doesn’t care. And in some cases, I shouldn’t say the plant doesn’t care. If the producer provides it and can provide it adequately at the right times, in the right amounts, in the right forms, the plant is really happy, and the plant will produce high yields. Because to the plant, all of that stuff was free. It didn’t have to give off water. It didn’t have to give off exudates. It was great. So we do a lot of things we think about. We’ve designed equipment to do great placement of inputs so that we put them in the right places near the growing roots, so that diffusion gradient can be more efficient. Placement increases the efficiency of the diffusion gradient, which is all great. But, again, if you don’t have — so this is the difference with what Dr. Tilman found, based on what Dr. Albrecht showed. In 1960, you had the microbial community that was far more active, that actually provided for, probably, closer to 80 to 90% of the fertility that the plant needed. Then, over time, because of the way we’ve managed things and when we add nutrient inputs, depending on the types of nutrient inputs that we add, again, if it’s free to the plant — because we provided it in the right forms, at the right time, in the right places — the plant doesn’t pay the microbial community with root exudates. 

So, as the plants stopped giving off as many exudates — because they didn’t need to, because the nutrients were free, so they didn’t have to pay for them — they stopped feeding the microbial community, which caused the microbial community numbers, their populations over time, to decline. So, by the time we got to — and again, in this study by Tilman, it’s in the 1990s because his study was published in the early 2000s — by the time we got to the 1990s, our fertilizer use efficiencies had gone way down because you don’t have the microbial community compensating anymore for the fact that the plant doesn’t take up those additional fertilizers. So, again, what we do is we’ve now tried to work with, well, let’s figure out a different time to apply, and that can help some. Let’s figure out a different place to apply. Let’s adjust our placement. That can help some. But the biggest assistance that the plant gets is from the microbial community that’s in the rhizosphere — the activity of the fungi and the bacteria, primarily, that are helping to break down those mineral nutrients, to break down organic matter that’s broken apart by microarthropods, breaking down all of that material — and, then, the mycorrhizal fungi that can take those nutrients that are now in the right form for the plants and transport them through a pipeline that directly connects. Without needing a diffusion gradient, you now have your mineral deposit over here, and you have a pipeline that goes directly from here to the roots.

TOM: So a lot of things are happening here. I have lots of questions. Define rhizosphere.

KRIS: Rhizosphere. Basically, rhizo is the Greek word for root, and sphere is zone or circle. So it’s basically the circle that’s around the roots. In there is where you have the majority of the microbial activity because that’s also where you’re going to have more moisture because of the roots and the dynamics that are there. And you’re also going to have the exudates that are coming. Those exudates are carbon-based compounds, different types of sugars that are coming from the roots to feed different microbes.

TOM: Okay, so you just answered another one of my questions. Okay, and then this pipeline that exists between the root and getting nutrients? Is that an active thing where it goes and seeks out nutrients? Or is it just kind of a willy-nilly thing I send out, and I find it or not find it?

KRIS: It’s a combination of both, but it’s far more active than passive. And the reason that it’s far more active than passive is, again, if you’ve got a mineral deposit over here, typically, with that mineral deposit, part of what helps to keep that mineral deposit in those nutrients, in a plant-available form, are the activities of bacteria and fungi. And they’re going to be giving off various types of signals and biomolecules that the mycorrhizal — again, the Greek word for root is rhizo. Myco is the Greek word for fungus. So you’ve got fungus-root fungi, and so the fungus, their bodies are these fine threads that come out from the roots and go out here. And because those signals are concentrated — those microbes are over here in the mineral deposit — their signals are concentrated there, their fungal hyphae, that pipeline, is going to go in that direction. Then, once it gets there, it has the ability to, then, like the roots, form branches. You’ll get branches that will just explode and colonize that mineral deposit area so that it can increase that efficiency of taking up those nutrients from that mineral deposit and then actively transport it back to the roots. 

TOM: So let me try. So we can increase the amount of fertility by putting on more in the right places, the right concentrations. And we can also increase the fertility efficiency of the plant by increasing microbiology, right? Both those things can work together. Okay. So I get from a standpoint of how, as humans, we control where we put our fertility, how much and everything. What is the mechanism to improve soil health and the microbiology so that we’re making that plant more efficient at going out and finding nutrients?

KRIS: So two things there. One is you mentioned putting more on in the right places and more on to a certain degree. If you put too much on, what ends up happening is you take the place of the jobs of the microbes. So, then, to the plant, it’s free. So you want to put more on, but as the saying goes, you don’t want to put so much on that you become a moron. The more on syndrome can lead to morons, which many of us are. That’s the first thing that you want to be careful of. Now, the other thing that you want to be careful of in this process is that you want to make sure that the plants are giving off the exudates — the carbon-based compounds — to the microbial community. And part of this is going into what we are asking the plants to do because the plants make these carbon compounds via photosynthesis. Then, they have to figure out how to allocate, how to distribute those carbon compounds in their physical structures and give them off as exudates. And part of their physical structure is the formation of the fruits, the grains, the leaves, the things that we’re utilizing for food. 

Normally, the plants have evolved over time because they knew, when they first came onto land and they started to grow and become multicellular and grow up and all of those types of things — from those algae, those photosynthetic bacteria — when they started to now grow into what we see as plants, those plants would allocate more resources below ground because they realized they had to work with the microbial community and start building up organic matter so that they could hold onto the water better and have a better growing environment and all of those wonderful things that they do. And the consequence of that is that those plants wouldn’t necessarily produce a lot of grain. They wouldn’t produce a lot of fruit, and they wouldn’t produce very big fruit because they didn’t need to. Now, when we have bred and selected for or genetically modified whatever it is on whatever spectrum you are on the production of plants that we utilize for growing food, in growing food for humans, we’ve changed the way that the plants allocate carbon. Because, before, most of the carbon that the plant made during the growing season went below ground to help to build soil in the microbial community. Now, you have to allocate so much more carbon above ground to make the grains, the fruits, the seeds, the leaves, whatever it is that you have been selected for making. 

So we’ve changed that allocation. Now, we can work with various types of heirloom varieties, and many organic producers are working with different types — and have worked for a very long time with — different types of varieties of plants. They’re usually lower yielding. But, again, they work better in this biologically-based environment, with the microbial community, where you’re working with trying to get the microbes to help you manage fertility. So we can utilize those varieties. But the other thing that we can do is also — and this is where things like cover crops, or companion cropping, or putting other plants on the landscape in your fields and in your pastures that you’re using, not for growing high-yielding cash crops. But you’re actually selecting for varieties that aren’t going to be high-yielding, and you’re growing them in such a way that you don’t grow them to the point of forming fruits. So you keep them in the vegetative phase as opposed to allowing them to go into the reproductive phase. And during that vegetative phase is when they’re going to be giving off more of the exudates below ground.

TOM: Okay. So I’ve just got to say, in the world we’re working in today, it’s usually: let’s take an easier approach. Let’s just put on what we need. Why can’t we just put the biology on the soil, dump it out there and be done with it?

KRIS: So you can put the biology on the soil, but if you don’t have any food for it, the biology is going to start to die. You can compensate, and this is where some people will utilize a lot of compost tea. But if you aren’t, again, providing the food for the organisms you applied through the compost tea, those organisms are going to die. And for a short time, their bodies are going to be the food for other microorganisms. So you’ll see an increase in biological activity, but it’s a short-term increase. You want to be applying compost, or you want to be adding some other sort of — and when we’re talking about food, we’re talking about carbon. So we need to add a carbon source to be able to get this activity to occur more. So, whether it is that you’re applying additional microbes, you need to apply them with carbon. Or if you’re trying to increase the activities in the microbes that are already in the soil, you need to also increase the amount of carbon that is getting into that soil.

TOM: So, Kris, is carbon carbon? Is carbon from manure the same as carbon from root systems? Is it the same as carbon from anything? Is it just carbon? I mean, can we go out and dump coal on our ground and get carbon?

KRIS: No. You can, and you’ll get some. People add coal or they add biochar. People will add molasses, which is simple sugar. Biochar, or coal, is more decomposed, highly condensed sugars. It’s basically what it is. You think sugar is sugar, whether it’s sugar that’s in molasses or sugar that’s in coal. But it’s not. And we know that it’s not because otherwise we’d be able to fire all of our coal plants with molasses if they work the same. But the amount of energy that’s in there is different. And that energy that’s in there is different because of the molecular structure that you have. So the idea is that things like molasses — so you do have producers. Again, if you add microbes, you also want to add food. So you’ll have producers that will apply molasses, and molasses can stimulate the activity of some microbes. But the activity of the microbes that are stimulated by molasses are typically bacterial populations. And they grow very, very quickly, and then they die off very quickly. So what we’re looking for is the diversity of all of the different types of microbial populations that are there. Some recent research has shown that, in order to have the functionality that we’re looking for from soil health. So soil health is defined by the continued capacity of the soil to function for plants, animals and humans. That function that you’re looking for comes from the integrated, interactive effects of thousands of different organisms.

TOM: Okay. So we can’t just apply one species or one type of microorganism and expect us to have a healthy soil. We need to go back to your biological tool, right? The soil takes a lot of different microbiology to make it run. It’s not based on just one thing, one whatever. 

KRIS: Exactly. Yeah, exactly.

TOM: All right. So, then, you have microbiology. You have a carbon source, but it also sounds like energy is an important source.

KRIS: Well, energy comes in the form of carbon. So the energy is in those carbon bonds. The great thing about the way that life has evolved — in particular, life has evolved on earth — is the majority of living organisms are carbon-based. And that carbon is the energy from the sun through photosynthesis, pushed into the bonds that are created between carbon atoms and carbon atoms, or carbon atoms and oxygen or hydrogen atoms. So that’s where the energy is. There’s more energy, depending on the different types of bonds that you have. So, again, as the sugars get condensed into becoming coal, there’s more energy that’s in there, in those individual bonds between the carbon atoms, because there you get double and triple bonding between the carbon atoms. So there’s more energy in there. It also is more difficult to break those bonds. So you break those bonds. More energy is released. But because it’s more difficult to break those bonds, it’s harder for many different types of organisms. So, when people apply biochar, biochar could be utilized by some organisms and can be broken down by some organisms. But it can’t be utilized by a larger concentration of organisms because having the right mechanisms, the right enzymes to break those bonds, is different. Again, not all carbon compounds are the same, and so it changes. So we take the energy from the sun, and we put it into these bonds. Then, those bonds and those structures have also become the physical framework for the bodies of pretty much all living organisms on our planet.

TOM: It’s not necessarily just carbon. It’s carbon bonds that microorganisms need. I know they need the carbon, right? That’s the building structure, but it’s the bonds that they need. And that’s why things like coal and biochar may not be as useful as manure or something else, that maybe those bonds are a little weak or easier to break, easier to utilize. Is that right?

KRIS: Yeah. As you said, it depends on the bonds. It depends on what they’re bound to. So you have things like CO2. We have lots of CO2 in the atmosphere. We’d like to get rid of some of the CO2 in the atmosphere. Why can’t we just put CO2 in the soil and feed the microbes CO2

TOM: So why can’t we?

KRIS: Why can’t we? Exactly. That’s a great question. Part of the issue is, again, the molecules — the carbon with two oxygen on it — doesn’t. Breaking those bonds and getting the energy from that isn’t the same as you would get from carbon that’s in a sugar form, where you have carbon bound to carbon and oxygen and hydrogen, or carbon that’s in a protein or an amino acid, which has nitrogen with it. So, with CO2, you don’t get oxygen. You don’t get some of the other elements that you need. Also, those bonds, when you break them, you don’t get the same type of chemistry. You get too little carbon for the amount of oxygen that you have there. So you don’t get everything that you need. 

TOM: You don’t get the right balance.

KRIS: You don’t get the right balance. Now, there are organisms like plants that can utilize CO2 and transform it into sugars via photosynthesis. You have other bacteria that can utilize CO2. You have bacteria. I mean, another great carbon source that we’d love to be able to use from our atmosphere is methane. Again, you have organisms that are in the soil, bacteria that actually can use methane and be very efficient at it. So one of the things, again, looking at how this is all — and I really want to emphasize this — it’s all very complex. We talked about a lot of different things, and they’re really cool. But the thing is they’re all part of this very complex system that is in these constant cycles of moving carbon and energy through all of these different organisms. So, when we’re talking about methane, one of the things that we’re starting to find is in some of the grazing systems that we’re using, we’re actually seeing the potential to increase the number of what are called methanotrophs, organisms that love methane and will actually use and eat methane. So they can take that methane and transform it from methane. So, in some of our grazing systems, how we’re going about managing the animals, we increase the concentration of these methanotrophs. They can then transform and utilize that carbon and will reduce the amount of methane that may be coming from our livestock systems. That is one of the things that we’re concerned about from a climate change perspective.

TOM: Kris, I want to just talk about, briefly. Carbon is stored in soils. We all have this significant interest in putting carbon in the soil. Not all of us understand even what that means other than there’s carbon in soils. How is carbon stored in soils? And as we look at greenhouse gases, what’s the most important type of carbon that’s stored? I mean, carbon is carbon, but I know it’s stored in different forms, if you will. In a simple way, can you tell us what we should be striving for when we’re thinking about putting carbon in soil? How should we be thinking about it?

KRIS: There are two really good ways of storing carbon in the soil. And one way is, on some level, a fairly simple way. And this is usually what happens deeper in our soils, where you get the formation of, typically, calcium carbonates. So it’s basically storing the carbon in an inorganic form. And when it’s in that inorganic form — and this can happen deeper in the soil — the chemistry of those bonds means that it doesn’t get broken down very readily, and it doesn’t get released back up into the atmosphere. Because part of the issue with putting carbon in the soil is, yeah, you can put carbon in the soil, but then it comes back out of the soil as CO2, as it comes out with the activity of the microbial community, as well as the roots. The secret thing about plants that we don’t think about is we’re always thinking about, well, the plants give us oxygen. But the plants also give us a lot of CO2. That CO2 comes from their roots. So that’s coming up out of the soil. So one of the things that we can do, again, is deeper in the soil, some of that CO2 — if the roots are deeper in the soil — can bind with calcium and become calcium carbonate. So that’s going to be an inorganic form, and that’s going to be more difficult. It’s more difficult to break that down. It’s very stable. 

TOM: It’s very stable. It’s not coming out in carbon gas anytime soon. It’s just stuck there. Okay.

KRIS: So, again, if we have a mechanism to get it down there — and the roots can be a transport mechanism — and they’re giving off CO2, that can be a mechanism to get CO2 down there to start becoming calcium carbonate. Now, the other thing — and this is what’s really exciting about agriculture — is yeah, that’s great. You get the roots going down there, but there’s nothing really to support the growth of the roots down there. They’re just giving off CO2 in that environment unless there’s the activity of the biology that’s there. So one of the things that we find is that the microorganisms, in doing the various activities that they do in trying to get nutrients to be in that plant-available form, they’ll utilize carbon to do that. And they’re transforming the carbon from that simple sugar into the carbon forms that are more stabilized. So part of the reason we have coal and natural gas and our other fossil fuels is that was sugar, at one point in time, that was part of the structures of plants and animals. But that got transformed by the microbial communities and put under pressure in time and transformed into these more stable carbon compounds. On the spectrum of that — rather than taking them from sugar and putting them into fossil fuels — on the spectrum of that is a bunch of different carbon compounds that can be stabilized for different durations. If we didn’t go and utilize coal to get energy from it, coal would be stabilized carbon in the soil for a very long time. Natural gas and all of our fossil fuels are the same thing, but it doesn’t go from sugar to fossil fuel right away. 

There’s a whole suite of different compounds that are created in that pathway. And that’s what we’re trying to do in agriculture because that suite of carbon compounds are the things that drive the activities and the function of soil that comes from the microbial community. So what we’re trying to do, with taking CO2 out of the atmosphere, is funneling it through the plants, into the exudates that go into the microbial community and having that microbial community essentially, biologically, chemically, physically and geologically occlude that carbon so that it doesn’t break down. And one of the cool things they do with this is they actually — and why I’m saying occlude, and I’m doing this with my hands. I gesture a lot. So one of the cool things is part of that occlusion is the formation of soil aggregates, or the pellets that are in the soil. And what we’ve found with research, again, has shown us that even carbon compounds, that if they were outside of the aggregate, would be broken down and go back up to the atmosphere as CO2 within a year or less. If they’re inside an aggregate, they actually will decompose at a much slower rate, meaning that they don’t get transformed into CO2 as quickly. So you don’t get as much CO2 coming off of the aggregate as you do outside of the aggregate, and they can last for decades. And the longer you keep things lasting, again, that’s how you get it to that coal pool. The longer it sticks there, the more it gets transformed into these more stabilized forms.

TOM: I assume, then, that also helps with organic matter, right? If we’re not releasing that carbon as fast, and we’re keeping it in that soil aggregate, we have a better chance of increasing our organic matter.

KRIS: So, yes, you build up organic matter. You build up. That improves your fertility because, when it’s in those organic forms, even as it’s being partially broken down, you get nutrients that will get bound to that organic matter. But the great thing about organic matter is when you get nutrients that are bound to it, they’re in an exchangeable form, which means that they’re not going to be readily lost. You could get nitrogen compounds. You could get nitrate that could come in and get bound to organic matter. And instead of that nitrate getting rapidly transformed to nitrous oxide, which is another powerful greenhouse gas, when it’s bound to the organic matter, it will sit there, bound to the organic matter, until something releases — typically a microbe or an organic acid from the plant roots themselves. So you have this ability to essentially take nutrients. Nitrous oxide is one of the consequences of it, getting phosphorus, becoming readily unavailable. If you get phosphate bound to organic matter, as opposed to phosphate bound to calcium or to aluminum or iron, that phosphate is more available. It’s in an exchangeable form when it’s bound to the organic matter. 

So it improves your fertility. It also improves porosity because, if you get the particles bound into aggregates, the aggregates don’t fit tightly against each other. There’s open space around the aggregate, and that’s going to allow for better gas exchange — CO2 — to get out of the soil and away from the roots, so the roots don’t suffocate and die, and the microbes don’t suffocate and die and oxygen gets into the soil. And more importantly, for us — as we go looking at our future climate — is issues that we have with water. We’re going to have fewer rainfall events. They’re going to be heavier rainfall events. So this porosity that’s created around the aggregates allows for more water to get into the soil more quickly and for more water to be held. Another thing is when it’s on a winding road — and one of the reasons why winding is important is that we talked about, before, the water is constantly being pulled out of the soil by evaporation, by the energy of the sun, and it’s constantly pulling. So evaporation is pulling it this way, and gravity is pulling it this way, so that we get groundwater. You get water that goes in towards the core. Those two forces are pulling the water away from the rhizosphere, away from the roots. If you have a winding path, it’s harder. It takes more energy or time to pull out of that winding path than it does to pull out of a straight path.

TOM: We keep more water longer in the soil. 

KRIS: Exactly.

TOM: So I’m kind of winding this down, Kris. I want to ask you a simple question about your profession. On a scale of one to 10, how much do we understand about soil microbiology?

KRIS: On a scale of one to 10, how much do we understand? 0.0001.

TOM: Well, you have a long career. Anyway, I want to thank you for being a part of it. I appreciate the time that you’ve given to Organics Unpacked. Your knowledge is unbelievable. I’m sure we will have you on again to talk more — I don’t know more in depth — but more broadly about soil microbiology and the things that we’ve learned for organic farming and to help organic farmers utilize these biology tools or biological tools better. I appreciate that. But two minutes. In two minutes, if you are sitting alone in a room with a farmer, and you had two minutes to tell them something about soil biology, when they leave that room, what is the most important thing you can convey to them in two minutes?

KRIS: In two minutes? What could you do to increase the carbon flow below ground, knowing that comes primarily from the photosynthetic activity of the plant? So can you plant companion crops, cover crops, relay cropping? What can you do to add more plants for more days of the year? That’s the other key. It’s not just more on a single day, but more days of the year.

TOM: Okay. I think that’s really good information to think about. And maybe in a future session, we’ll have to talk about even more: What are some things that organic farmers can do to increase the amount of organic carbon, not only at one time, but throughout the year, in their soil? But thanks, Kris, very much. And thanks to the listening audience for another episode, and be sure to tune in next week when we’ll unpack another facet of organic farming. Thank you very much. 

KRIS: Thank you.

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