Symbiotic Relationships in Ecology with Dr. Don Huber

Hi friends, I am John Kemp, hosting this podcast. I am passionate about developing regenerative agriculture systems that improve soil health, produce crops that are completely resistant to diseases and insects, and produce fruit of such an exceptional quality that we can have a legitimate conversation about growing food as medicine. I've discovered that there are many people with incredible knowledge and information about soil and plant systems and how to develop regenerative agriculture systems. However, much of this knowledge and this information is scattered. It's found all over the place, some of it has been published in peer reviewed publications, but there are many incredible stories and a lot of knowledge that has not been published and that hasn't been shared with many people. I started Advancing eco Agriculture in 2006 to bring this knowledge together in a more coherent fashion and incorporate it into products and growing systems and that growers can easily put into practice. It's my personal mission to have these regenerative agricultural systems become adopted globally and become the mainstream, the status quo against which all other growing systems are compared. To help achieve this goal, I want to share the knowledge that we have learned in the last decade and make it available to everyone while we have developed products at AEA that embody the principles of regenerative agriculture systems and make them easier for growers to apply this knowledge and these principles can be applied anywhere and when they are applied properly, they will always increase farm profitability and resilience to climate stress. If you have any questions, suggestions, comments or ideas, topics that you would like for me to discuss, Please connect on LinkedIn or on Twitter where my username is visionbuilder7 or you can also email me at john kempf.com I would very much like to hear from you and to hear your feedback. Be sure to subscribe to this podcast and thank you very much for listening. Enjoy the show.

Greetings friends and welcome to the Regenerative Agriculture Podcast. On this podcast we explore the science and the practical application of regenerative agriculture ecosystems, how to regenerate soil health, crop health and quality and increase farm profitability. In this episode, I'm very excited to welcome Don Huber to our show. Don has had an extraordinary life experience contributing a great deal to our collective knowledge of plant pathology, developing disease suppressive soils, and the possible long term impacts of herbicides and pesticides. Don, welcome to the show. We're very honored to have you.

Thanks John. Privilege to be here.

Don, you've lived a very rich life experience. What are some of your most memorable moments that led you to where you are today?

I just have fun Wherever I am, there's any particular time been a few challenges, but those helped you grow and help you focus on what you really want to do and where you think you can be of greater service.

What was something in your research work that you puzzled over for a really long time that you struggled to figure out?

Well, there've been a number of them. When you study soil ecology, you're looking at a black box. So the pieces to the puzzle have to come a little slower than they might for some other programs or other areas. But you start working on the border and then you start filling in the center. And as that puzzle builds a little better, you get a little better picture of all of the dynamics that's really involved. And I think that. And the greatest challenge and the most rewarding to gain some comprehension of what that black box really is doing, its dynamic nature and its critical importance, and the overall production scheme of things.

What has been something that surprised you.

How everything can be working at one time that seems to be contradictory.

Can you give me an example of that?

Oh, I think you have your part of your nutrient relationships, or you have microorganisms that are responsible for changing valent states of various minerals, so they're more available or less available. And you have those going on at the same. Both of those directions going the same time in some capacities. So it's kind of a matter with manganese or iron or some of those things, how some of the secondary, or what we would. What I would consider the more secondary functions come into play so that all of that can really take place and be manifest in a very positive manner. Even though what you might be looking at or the test that you have may not show the complete picture, you have to realize that it has to be going on in order to complete the cycle. And so it's a matter of either developing the techniques or understanding how all of those organisms interact together, what the ecological niches are that make the system work so that you have everything isn't just one big pool that's put in there and somebody's stirring the whole thing around. You really have a community of functions that are taking place at the same time. But you don't have the same gas station at every corner or a grocery store or at every corner. You have each one of those different functions that is taking place to end their own little scheme of things so that the overall system is a very functional, very dynamic relationship relative to the plant and its needs.

One of the pieces that you and I have discussed in the past is the challenge that we are seeing today with manganese availability. One of the I would say that as much as 80% or more, perhaps even 90% or more of the crops that we work with today often come back showing inadequate levels of manganese. What are the major factors that are contributing to that?

Well, yeah, manganese availability has a very dynamic relationship with the soil bacteria, also with many of the fungi. So that you have organisms, your mycorrhizae and that increase uptake of manganese as well as zinc and phosphorus and some of the other nutrients so that if they're not functional, you miss that ability to absorb and to interact with tremendous volume of the soil where that mineral might be in short supply. The other thing is that you have the bacteria especially that are responsible for the valent state. You have the oxidizing groups and you have the reducing groups so that the plant can utilize only the reduced farm of manganese. The MN2 plus, the MN4 plus farm is non available. We see that primarily present in the soil where we have high phosphate levels or high oxidative relationships so that the material can be there and yet not available for uptake. We see it commonly with many of our pathogens because the pathogens again utilize manganese oxidation as a virulence factor. When we looked at several thousand isolates of Glomonomyces graminous that causes take all on a wheat from all over the world, we evaluated those and we found that there was one characteristic that is common all of the virulent farms and that's manganese oxidation. If it can't oxidize manganese, it will never cause disease. The same thing for rice blast. Same thing for isolates of Streptomyces, babies of potatoes, Gab path and a number of other pathogens. So that just the ability to oxidize manganese to a non available farm and compromise the resistance of the plant to those pathogens. And if the pathogens can't bring about that compromising of the availability of manganese by converting it to an oxidized from a reduced farm, the fungus is essentially just a good sacrifice in the soil. And same thing with many bacteria. So we see these direct effects on mineral availability as being involved in not just growth and quality and nutrient density, but also in susceptibility or resistance to disease. You have the virulence relationship of the pathogens, bacteria and fungi in the soil related to those minerals that are necessary for the plant's defenses. And you also see it in those minerals directly related to growth and resistance of the plant. To those pathogens and its overall physiological functions. It all fits together very nicely if the system is balanced, if it's favorable. And that's one of the things that we tend to forget, is that when we're farming, we're really managing an ecology. It's not a matter of just this silver bullet for this problem, or silver bullet or stinger missile for another one. It's really, really a matter of having that ecology work for us and support plants. If we don't do that and we upset that system, then we compromise the overall quality and productivity potential that we have in our soil.

I'd like to go back for a moment and just clarify one of the points that you were discussing. You said that there are a number of pathogens that are dependent on manganese oxidation, and if they're unable to oxidize manganese, they just become saprophytes in the soil profile. Does that. Are they dependent on that manganese oxidation directly, or as in they personally require it, or are they just producing a manganese deficient plant that is now susceptible to invasion?

Both of those statements could be correct. They don't necessarily need the oxidation. Many of them are also, or some of them are also reducing organisms. In other words, you change the environment or you change the association that they have with other organisms, and they may be strong reducing versus strong oxidizing organisms. We see that especially with the pseudomonads and a number of other organisms, where you change the soil environment and they can either benefit you or via or even a direct pathogen involved in that by compromising that resistance.

So.

The microorganisms use those minerals just like the plant does, or just like we do. Our metallo nutrients are strong transition elements for electron transfer and physiological processes. They're the key factor. The cofactors are. Enzyme function doesn't require very much of them. But if you don't have that specific cofactor that's involved for an enzyme, that enzyme isn't going to do any work for you. Just. Just another protein that's sitting there. And about 80% of our proteins in plants are what we call metalloproteins. Well, the metallopart is a cofactor. It's a very small part, but a very critical part as far as function of that physiological pathway.

In essence, what you're describing is that as long as plants have adequate availability of reduced manganese, you have resistance to all the diseases that you described.

It would be very, very critical for that resistance or the physiological functions in the plant. Without those minerals, one of the pieces.

That you and I have discussed in the past is the populations of some strains of Verticillium in the soil profile when you have a crop that is infected versus a crop that is not infected. How do populations change when you have a crop infection some of these pathogens?

Well, the plant is providing nutrients and resources for the pathogen when it comes to Verticillium. Verticillium is a common soil inhabiting organism rather than just the soil colonizing organism. So that if it's soil inhabiting, it's able to survive in the soil on its own. It really doesn't need the plant necessarily to continue its life cycle in the soil. Soil inhabitant or a soil colonizer is an organism that as long as there is a host there that provides that nutrient base for it, it can be very serious or have a very high population. You'll see most of your Penicillium and Aspergillus species that you always isolate in very high populations, but they're only associated with high organic matter and those materials that provide a rich nutrient based for them. If you take the organic matter out of the picture, the nutrient base, they aren't able to survive very well. Compare that with Mucker or Fusarium or Rhizoctonia monomyces and your regular soil borne pathogens, Phytophthora. You'll find that those are going to be in the soil at a similar population regardless of what you have from nutrient bases as far as whether the plant's there or not. Population of Fusarium may bounce around when you add the plant because you're providing an additional nutrient source for it. But its population is high enough in almost all situations to cause extreme disease, even in the absence of the host plant. You can have 100% infection if you inoculate sterile soil, for instance, where, if the difference is where, you have a lot of other organisms that will suppress that virulence relationship that the pathogen has and it is maintained either in a dormant state or it's with some of the fungi. Refer to that as fungus stasis or a dormant state. Just because you have an intimate association with bacteria or other organisms in association with that fungus that prevent its pathogenicity. Maybe those other organisms may be utilizing the extracellular enzymes that would oxidize manganese or perform other functions that reduce its virulence, but they don't necessarily reduce the population of the pathogen below a level that would cause extreme disease. It's just that they change its ability to cause disease so that it's more like a sacrifice than it is a strong pathogen.

That's absolutely fascinating that we can have these soil inhabiting pathogens that are present in populations that obviously these populations can shift. But it's intriguing to me that essentially what you're describing is an infection is not the result of the presence of the pathogen. It's the result of the level of plant health and a result of the microbial ecology in the rhizosphere.

Essentially what you're describing that's correct for the soil borne pathogens. When it comes to the soil inhabiting then they're dependent on that both very definitely for a nutrient base and for a disease relationship with the soil inhabiting. We see a dramatic effect of crop rotation length between susceptible crops and those things. We can see it also with the soil. We see that relationship with the soil inhabiting not because of presence or absence of the pathogen, but by the specific interrelationships that we have with different organisms with the pathogen, with the soil colonizing where they can. An organism can colonize as long as there's a nutrient source part or organic materials part to get that nutrient source from. Those are more direct effects of where you see population dynamics and the typical epidemiological programs or processes going on in the soil. Where with the actual soil colonizers you see the interaction of other organisms in the that disease suppression. An example of a soil inhabitant versus a soil colonizer would be soil colonizer would be Fusarium Rhizoctonia vertistylium. Those organisms, the soil organisms that would respond to population dynamics would be your nematodes for one, but also things like anthracnose or other organisms that once the nutrient source, the host residue is decomposed and pretty much gone. The pathogen isn't able to survive in the soil against the tremendous biological buffering and interactions that take place in a normal soil.

When what are the tools that growers have available to them to manage soil ecology most effectively and to develop a disease suppressive soil profile. What are the most effective management strategies for managing soil ecology?

Well, from a dynamic standpoint, crop rotation has the greatest effect and again that's going to depend on the particular pathogen that's in the ball. But each crop manages our influences a certain group of organisms in the soil and those then are going to be enter into that relationship. What we found with alfalfa when it was introduced as a crop, it was a total failure for us for a few years until we recognized the importance of symbiotic nitrogen fixation and we started adding the, the legume inoculants. Then in order to have that free nitrogen, that made an economic crop for us. Without that, it was we were having to add nitrogen and other minerals. But with that symbiotic relationship, we get for nothing or we get for free, essentially by having those organisms fix atmospheric nitrogen into amino acids for the plant to utilize. So that would be an example of that symbiotic relationship, just from a nutrient standpoint. But crop rotation will influence each group of organisms, so that it makes it very easy, if we're developing a desert soil, to build up disease suppressiveness. And we can do that strictly by the crop sequence that we have, build a biological buffering capacity in the soil and a desert condition, because those soils have very low microbial population and activity to start with because of the lack of water. When you get a cultivated soil, becomes much more difficult to shift that biology and the direction that you want. And for some pathogens, we've never been able to find a crop rotation that will do that. But for most of them, we can modify the disease expression, even independent of population of the pathogen, by favoring certain other groups of organisms in that relationship. But crop rotation would be the first, probably the most dynamic effect then on, on the soil population. We can do that either primarily through crop sequencing. You'll find that the immediately preceding crop to your target crop that you're working on is going to have about 85% of the overall disease effect on it. You'll find we can accomplish that with COVID cropping. You don't necessarily have to take, eliminate your economic crop. With COVID cropping, we can do much the same type of thing, as well as get some additional synergy from a nutrient standpoint. So when you look at how to manage that soil, we're looking at the influence of root exudates and the influence of a particular crop, what it leaves in the soil, how it influences nutrients that then are available to the pathogen. Also are the other saprophytic organisms that would influence that soil ecology. Certainly tillage has a very dynamic effect. Time of tillage very important, especially in the temperate climates. A little different in the tropical and arctic environments. But arctic and temperate, your tillage, as time of tillage becomes very important, because what you're doing is disrupting an ecology that's established in a no till situation. And you're trying to activate or suppress different organisms that have established kind of king of the hill relationship with the system that you have. Hillage changes that overall ecology by getting some air into the soil, getting nutrient distribution and stirring up those organisms that some of them are kind of like we are. If they don't have a burr under their saddle, they don't do much work for us. And so you're stirring them up in the temperate environment where we have winter seasons and summer seasons, whatnot. You'll find that with fall tillage after your crop as it if you'll do the tillage then you'll see more pronounced or a more dynamic relationship than you'll see with spring tillage and fall tillage. You open up, the soil comes very oxidative for organisms to have that fresh charge of breath. And then over winter you re establish those ecological niches so that your anaerobic functions can take place and still have your aerobic functions taking place. So your reduction of nutrient farm or your oxidation of nutrient farm, then our rebalance in the spring when we do a lot of tillage, you don't have time during that immediately or crop that immediately follows your tillage operation. There's not time to reestablish a lot of those ecological niches that take some time. And so you get a different effect. And it can be more negative effect. It may be a more, more positive effect. Again, depending on your crop and your overall disease organism or overall nutrient status that you're dealing with in a particular soil, whether it's a clay or clay loam or silt loam soil versus the sandy loam soil, you see those ecological relationships shifting or changing in a dynamic relationship relative to time. Moisture becomes a very important factor for changing those ecological relationships. And pretty much anything we do management wise is going to influence that soil ecology. That's why farming, we're really managing an ecology. And by learning what your soil is, what your biology is, you can pretty much control most of our diseases through that management activity. Unless you're doing something that is very detrimental or has long term effects on biology.

That's a very impressive statement. We can manage disease and pathogenicity based on how we manage our soils from a cultural perspective. That's a very, very important perspective that I think we don't commonly hear in agriculture. You mentioned a number of different pieces, a number of different management tool, cultural management tools, crop rotations using cover crops, tillage, the impacts of moisture. And I wanted to clarify earlier you spoke of the differences between soil borne pathogens and soil inhabiting pathogens. I believe it's fairly well understood that we can use crop rotations and so forth to manage soil inhabiting pathogens. Are you Suggesting that it's also possible to use these tools to manage and suppress soil inhabiting or excuse me, soil borne pathogens.

Oh, very definitely. Most of our soil borne pathogens we have very limited genetic resistance. As far as a full resistance, we rely on those management techniques to control those pathogens. Sometimes we don't recognize it as much as we need to. But soil borne pathogens have much more limited relationship. As far as the population dynamics. We may measure population of spore load and other things for organisms like Fusarium, but the population, the organism is there and plenty and a high enough population that regardless of what we do, if we didn't have the other organisms associated with it, it would take our crop. What we do with our soil colonizing is that they colonize only as long as they have a nutrient base to function with. So that we can either extend the time between susceptible crops as we do typically with most of our potato pathogens, for instance, that we would would see them building up in two or three crops and would want to break that drop population down. Same thing with anthracnose on corn, that it's a soil colonizer Cephalosporium on on wheat. All of those organisms survive in the residue. Many of them even produced an antibiotic so that they slow down residue degradation to extend their lifetime in the soil and that so that other organisms aren't able to colonize that food base, which is quite different from Rhizoctonia or Fusarium. Many of the basidia mycete type pathogens are very excellent soil inhabitants. They don't require the base of nutrients that many of our just colonizers do.

You spoke briefly about the use of crop rotations and that 85% of the effect from a in terms of disease suppression happens from the prior crop or the prior cover crop. What are some particularly useful crops or cover crops that have a very strong disease suppressive effect?

Again, that's going to depend on your disease and your overall soil biology. But you'll find for instance, if you're dealing with take all Guamonomyces graminis, the root and crown rod of cereal crops, you'll find that your Brassica species have a suppressive effect. Perhaps the best crop overall is oats, another cereal crop. But with oats we bred into those when we bred ground rust resistance, it also gave us an oat crop that provided disease control for take all control or wheat and barley. Reason is that crown rust resistant oats also produce or produce glycocyanide root exudate that suppresses the manganese oxidizing organisms and you suppress the manganese oxidizing organisms, which it also suppresses the manganese oxidation by the pathogen that is required for virulence. So you've increased the manganese availability for the plant for its own resistance. And the shikimate pathway is the pathway that gives tolerance or resistance to take all because that's where the lignotubers are farmed. Your lignification, your callousing, and all of those materials are through the shikimate pathway. And manganese, a very critical component in that pathway. At six or seven different steps in the pathway. If you inhibit the availability of manganese, have a good strong chelator, mineral chelator that ties up manganese, you're going to increase take all because you reduce the availability of functional availability of manganese for the plant in its own defenses. Now you have a plant like rye, very efficient in manganese. And your other micronutrient update, Rye takes care of itself so that it's quite resistant to the take off pathogen, but it doesn't do anything for a subsequent crop. It barely does very well with very little disease pressure because it's very efficient in taking up manganese and other micronutrients. If you have triticale, which is a wheat rye cross, if it doesn't contain that sharp section of the right chromosome that is responsible for micronutrient uptake, then the triticale will be as susceptible to take all as the wheat crop, the parentage, so that it goes that way. But it doesn't. You don't get a crop benefit or a crop rotate, crop rotation benefit out of the oats or out of the rye like you get out of oats with oats, with the rude exudate that is a very strong antimicrobial compound against the manganese oxidizing organisms that make manganese less available, you'll see that effect then that change in the soil biology carry on for two or three wheat drops after an oat crop that will have very limited, very little takeoff, probably the most dynamic effect. Then you get into the Brassica species, your Canola and some of those mustard also produce your Quinlan and some of those materials that have a similar effect to the glycoprotein that the oats would have. And so you'll see reduced take all following canola. You'll see an increase in some of the other diseases when that happens, so that it's not just influencing one particular disease, but especially with canola, if you're using A ground up ready canola, genetically engineered canola where you're adding a very strong mineral chelator and that's how glyphosate works, is by tying up those minerals in the physiology of the plant. But if you're adding or if you're growing canola roundup ready canola and applying the glyphosate to that, gonna move down into the out of the root exudates and change that soil biology, then you may see a reduction in take all. But you see a very dramatic increase in Fusarium root rot as well as Fusarium headscap and the toxins of that particular plant pathogen produced. So you're changing the dynamics of the system with each of the particular management tools that you might be using.

When you speak of the disease suppressive effects of oats and brassicas, what are the key characteristics that they share in common that perhaps are also shared by other disease suppressive crops? And I'm asking this question just, I think it would be wonderful for our listeners to have an idea of what are the various crop types or what are the characteristics that they can use to help develop a disease suppressive soil?

Well, many of those are worked out and you know, just from empirical information, but it all boils down pretty much to nutrition one way or another. It may be indirect through that antibiotic effect of the root exudates on particular groups of organisms, or it may be a direct effect on increasing the availability of a specific nutrient. I mentioned the take all situation with manganese. You'll see the same relationship of manganese with potato scab and with Verticillium wilt a little different involvement in the physiology with Verticillium wilt where you have a vascular pathogen versus cortical pathogen. But it's again the availability of that nutrient or the non availability that determines what the disease severity really is. We're concerned in bananas for the loss of the Cavendish banana because of the resurgence in Panama disease, Fusarium cubens. And yet that pathogen has always been there. What we've done is change the management and the soil ecology then that provide an opportunity for that pathogen to become more virulent and to manifest itself. We've changed it from a saprophytic organism essentially into a very virulent pathogen and haven't recognized what those changes are usually that are involved in that, that shift and this situation with the cavity, you have a tie up of zinc and again the involvement of very strong mineral chelators that we're using in our Chemical agriculture.

You spoke of the effects of tillage on developing different microbial profiles. And I wanted to clarify that. Are you suggesting that with fall tillage applications that we get a rebalancing effect of both reducing organisms as well as oxidizing organisms?

We do, and it depends. It doesn't have to be every year, but there are some changes that take place with long term no till that reduce the efficiency of the ecology. For nitrogen especially, you'll have over tenfold greater nitrogen reduction, denitrification and no till than you have in a conventional tillage. Even though in conventional tillage we would have more oxidative environment, you'd think it'd be the opposite, but it isn't, because denitrification is an anaerobic process. And so if there's any way for that nitrogen to be converted, nitrate, nitrogen, and a no till situation, it's going to be very rapidly converted to elemental nitrogen and move back into the air. You'll see all your nitrogen, nitrous oxides and those materials then that are evolved from no till much more extensively than they are from a conventional. So it's a balancing situation and we're managing an ecology. And there are several studies that have shown with long term tillage conservation, tillage and some of those things, but you haven't had any real soil disruption for eight or 10 years. Just a single shanking through the soil will increase soybean yields 50%. You don't have to do that every year. You don't have to beat your soil to death in order to get those effects. It's a matter of getting enough shift in that soil biology, enough activity, and that we get the desired result. From a nutrient standpoint, what are the.

Impacts of nitrogen and nitrogen applications on developing disease suppressive soils?

Most of your soil organisms are hungry for two things. One of them is going to be nitrogen, the other one is going to be carbon. So when you change either of those nutrients, you'll see tremendous stimulation of a lot of organisms in the soil, depending on what your source of nitrogen is. You get down into Florida and they're one of their primary pathogens on a lot of their crops, vegetable crops, is Fusarium oxysporum. So if this is a vascular Fusarium, they can get pretty much complete practical control by using nitrate, nitrogen and calcium, so that if they can stimulate nitrification, or if they apply nitrate, nitrogen, potassium nitrate or calcium nitrate, and also have use some liming to get their ph up so that you have that nitrogen held in the nitrogen form, you have fairly effective control of Fusarium wilt diseases. If you are looking at tobacco, where we would use fumigation for control of some of the soil borne diseases, you should have at least 30% of your nitrogen as nitrate nitrogen. If you don't, the plant is taking up all ammonium nitrogen. You can get into a carbon deficit because the plant will detoxifies the nitrate or the ammonium nitrogen by combining with photosynthate and carbon from photosynthesis. That provides the carbon base for those amino acids and then the nitrogen is translocated as the amino acid. If you don't have enough nitrate nitrogen present, you buffer against that high ammonium source that you're going to get after fumigation. Because our soil fumigants tend to knock out nitrifying organisms. So that you don't get nitrification there stabilizes it in the ammonium form, but it can act the drain on the carbon, on the energy availability. Then until that ammonium is detoxified and utilized by the plant. So there are changes that take place in that overall function. I don't know if that answered your question.

I'm thinking about what you've described about how many of the soil borne pathogens, soil borne fungi such as Bercerium and Verticillium for example, are dependent on oxidizing manganese and limiting manganese absorption by the plant. If that were the case, what would be the impact of adding ammonium to such an ecosystem where you have a reduced form of nitrogen? What would the impact of the ammonium be on these soil borne pathogens?

On that group of pathogens you'll see a tremendous reduction in disease. So that's with the ammonium nutrition. Have a chapter in one of the annual reviews just on the impact of form of nitrogen. So that you'll see tremendous benefit with different organisms by just selection of the form of nitrogen that that plant is going to be predominantly supplied with. You may not have to provide the farm of nitrogen. If you modify the environment so that those soil microorganisms make those conversions, you'll see that the change that then that form of nitrogen will be available for the plant. So it's important that you have both the management tools as well as the farm. Most of our soils, nitrification takes place very rapidly. You need to do something to inhibit nitrification. We can do it, we can do it biologically there to modify the speed of that reaction. So we can increase the amount of nitrogen, nitrate or ammonium, but with when it's taking up ammonium nitrogen, you have a reducing environment. That reducing environment is favoring your manganese reducing organisms so that you'll almost always have an increase in manganese availability for the plant when you use a predominantly ammonium form of nitrogen, the more rapid oxidative form when you're using nitrate source of nitrogen.

What is the impact of carbon to nitrogen ratios on both disease suppressive soils.

And also on yield Carbon nitrogen ratio, again, depends on the carbon source. That got me into trouble with my first publication in Plant Pathology. I challenged the carbon nitrogen ratio hypothesis where they were saying that that if you have this ratio, a 12 to 1 ratio versus a 40 to 1, you'll always have this disease relationship. And I demonstrated that it's not the carbon to nitrogen ratio, it's the form of nitrogen that is involved in that ratio. You can take different crop residues or different cropping sequences and it's the effect of that sequence on the form of nitrogen that determines what the disease reaction is. And of course, the effect of that form of nitrogen quite often is an effect on manganese or zinc or copper or other nutrients along with the form of nitrogen. But carbon nitrogen ratio works if you're working with the same nutrient source, our crop or crop residue, and then vary the nitrogen ratio by either harvesting it when it's greener or harvesting it when it's drier when you have wider carbon nitrogen ratio. But the carbon nitrogen ratio per se isn't the factor that's involved there. It's the effect of that ratio on the form of nitrogen and the mineral, other minerals that are involved, such as your manganese or zinc or iron or copper, that are all critical for particular physiological processes.

Don, one of the big pieces that I believe is quite important that we haven't spoken about is the just the general impact of photosynthesis and the quality of photosynthesis, or perhaps I should say the quality as well, but perhaps really the quantity of photosynthesis that can vary in crops and in cover crops and how that influences the volume of root exudates. How, how can a grower, how can we increase the quantity of photosynthesis and increase the quantity of root exudates in the soil profile.

Of course you're not going to have any photosynthesis if you don't have manganese. Manganese is critical for splitting the water. You provide the hydrogen then to combine with carbon dioxide. Not going to have any photosynthesis without magnesium as part of the chlorophyll molecule. Not going to have very efficient photosynthesis without iron. And sulfur and all of your other minerals, because your physiology is all tied together as a system. And if you want to improve the efficiency of photosynthesis, first place to look is going to be your mineral availability. Having that system work so that you don't have a backlog of sugar as fructose or glucose, you want that sugar, you need to be stored as sucrose changes the osmotic relationship, changes the overall physiology of the plant. It can be converted then all the way to sucrose. Well, you're also not going to have any sucrose if you don't have manganese, because it's responsible for your sucrose phosphate synthase enzyme as a cofactor. But it's a system that works together. You don't have sulfur, you don't have enzymes, because most of your proteins are initiated with either cysteine or methionine, your sulfur amino acids. And again, see, your C4 plants have a more efficient photosynthetic pathway. They have PEP carboxylase as well as the rubisco enzyme to capture that carbon dioxide from the air and combine it with the hydrogen that is split off the water by manganese. So you have C4 plants, C3 plants, and the physiology that's involved. But all of them require the mineral nutrients for the fishes, and any one of those deficiencies influences the overall efficiency of the whole process.

In the research work that we have done in the field, looking at various crops, I have suggested that what we have come to accept as common or normal, I suppose, depending on how you define normal, are crops that are photosynthesizing at only a fraction of their inherent capacity, perhaps as little as 20 to 25% in a few cases, perhaps even less than that. What are your thoughts? Do you see the possibility for plants to increase photosynthesized photosynthesis volume much more than what we normally anticipate?

Oh, we're only touching the tip of the iceberg as far as what the potential of that plant is. And probably the most limiting factor is carbon dioxide. You increase carbon dioxide, if we would just increase it a small amount, you'll have an exponential increase in the amount of photosynthesis, which then gives us the oxygen that we need, so that again, the system's tied together. If we limit carbon dioxide, we limit the amount of oxygen that is available for our growth and our youth also. But there are many things we can vary the structure, the morphology of the plant from a leaf standpoint to capture the sunlight more efficiently. Doesn't do much good to do that. If we don't have the carbon dioxide available, and on a corn plant, for instance, 250 bushel yield potential, 20% of that carbon dioxide is coming from the soil. So that if we have a sterile soil, we don't have respiration going on in the soil and utilization of that organic matter that we're applying to the soil so that we can get that respiration and carbon dioxide, we compromise the photosynthesis because there's not enough carbon dioxide in the soil to produce that high yield potential and the quality of the crop that we want without that additional carbon dioxide coming from the soil and the turnover of organic matter. So organic matter is great in the soil. We want to maintain it for a number of reasons. But if it's just sitting there as straw, all as stubble, not decomposing, as we see in some of these cornfields, where all of the, all of the residues just sitting there, tear up your tractor tires, it's not doing as very much good from a production standpoint. We want to have it breaking down. We want to farm the humates, the folvic acids and those materials that give us that overall ecology in the soil, that give us crop production.

And one of the pieces that I have said which really captures people's attention is one of the important reasons to have soil organic matter is so that we can lose it, so that we gain.

That's correct. We're still limited on carbon dioxide and our C4 plants are so efficient, and yet we're not tapping into that efficiency on the plants because we limit our carbon dioxide. Again, like you say, if it's not working for us, it's really working against us. From an overall system standpoint, when we.

Look at the horticultural space, indoor greenhouse production, when we increase the CO2 levels to 1100 parts per million, that increase with the exact same lighting, exact same environmental conditions, produces about double the plant biomass just because of increased photosynthesis.

That's correct. Our limiting factor in many of these situations is carbon dioxide, our most limiting mineral. Yeah.

So what is the potential for plants to increase the volume of photosynthesis?

Well, the increase the potential is 100%. I mean five fold tenfold depending on where we are now and what the plant is. There are number of different ways to do that. That again I mentioned plant morphology, but can also do it with increasing light intensity. Light got a lot of leaves on a corn plant, mature corn plant or corn plant at tasseling time that aren't getting very much sunlight. Not photosynthesizing near what Their potential would be because of that lack of sunlight. That's where morphology comes in. But plant spacing. We can increase the number of ears on a corn plant. You look at the tremendous work that Gary Yohal is doing at Purdue, for instance, as a corn breeder, corn geneticist, five and six years on a corn plant so that you increase the efficiency of that plant and you don't need as high a population so that you, you can minimize that crowding and that shading type effect. There just a number of ways that we can do that. We can reduce the allelopathic effect of our plants when they're to increase the population and corn very critical that you have even germination. If you delay germination six to eight days, you automatically reduce the size of your ear by the lollipastic effect, that auto intoxication of effect of the root exudates on an adjacent plant by as much as 80%.

Wow.

When the John Deere max emerge platter came out, I remember how it was almost an instant success because it increased the soil seed interface, that contact that gave you that uniform emergence. And so you minimize that a lollipopathy auto intoxication suppression that you had otherwise from those higher populations, we could increase our population and maintain that full yield potential without having the lullipathic chemicals reducing the overall production potential of that particular plant. There are just a number of things we could do if we needed to. Right now we're concerned about a surplus and maintaining market and those things. The biggest thing is that necessity is still the mother of invention. But there's plenty of potential there. When group of us that in our team programs that we had at Purdue University, a lot of us had the privilege of working in and one of our huddle sessions or brainstorming sessions, we asked Charles five what the genetic, potentially biochemical genetic potential of a corn plant was. And he said oh, let me work on it for a little while. And a couple of weeks later when we were all together, he said I've got your answer. And we were shooting for 350, 400 bushel. We knew that a lot of our better farmers this would be back in the 19 late 70s, a lot of our better farmers had the potential for 550 or even 600 bushel, that we were trying to design some systems for them to achieve that on a field basis. And Charles sat down and we said well, is this 600 bushel really a realistic figure? And he said oh, he said, you're all pessimists. Biochemical genetics of that plant are about 1100 bushel.

Wow.

And so you see what we could do if we managed that environment and the plant in a proper manner and provided the expression, we probably won't come close to achieving that until the necessity is there. Probably the most limiting factor that we have to achieve that is the innovation of man. And you see, as long as we're doing okay, we don't have that burr under our saddle. That would have us look at both the genetics as well as the environment to get expression of that genetic material.

So what yields did you end up achieving on your yield trials that you were conducting?

We could get 400 bushel. You had farmers that were getting. That was time with Herman Warsaw and the group that were 350 or the average was still 75 bushel. They were doing three or four or five times what the average was on a measured piece of land. They were doing it because they recognized that it's an ecology that we're managing. And they started out with the soil, had a beautiful soil. I remember visiting Herman Warsaw's farm, and you could take a steel probe and you didn't have to lean on it. You just pushed it in the soil three feet. He had that system working for him very well. You get into some of the other neighbors and try and push that. You get it down 3 or 4 inches and then had to really put some pressure on it. You get it down foot and a half and you're driving it in. I can't tell you how many of the old king tubes are still sitting out there in the field. That was. Those were tubes that you could drive into the soil, collect the soil sample at 3 and 4ft. And in order to get it in a lot of our soils, you're using a sledgehammer. Then the problem was pulling it out. You tear the metal off of the tube with the jack and finally you just crimped it over so that it wouldn't tear up the tire and you left it there. There are a lot of them still sitting out there in those fields because we didn't have that concept or the soil wasn't a major part of the management program. We in general would look at the nutrients and forget that all of that's part of an ecology that needs to be managed so that you have water percolation, you have your biology, your air exchange and those things that have to take place if you want to capitalize on the genetic potential of the plant.

What was the plant populations that growers were using to achieve 350 plus bushels per acre.

Well, one of the. You had the old Pioneer 3532. I think it was hybrid that took up 95% of its nitrogen by casting time and then it merely recycled it. So get onto sandy soils. It was a great hybrid because you couldn't maintain your nitrogen availability in those sands and it would take it up and store it. But it had a yield potential of about 125 bushel at 24,000 plants, which was our standard at the time. But you could increase the population of that particular variety because it didn't have the allelopathic effects from the root exudates with high populations. It had a fixed ear so that as you increase the population you still maintain that same ear length. It wasn't a big ear like your, your higher yield hybrid, but it was very stable and it tolerated high population. So they got the yield up by increasing population with their other varieties, our high yielding varieties, their hybrids. There you had a more of a flex error that related to the environment more dynamically. And the higher the yield potential, the more nitrogen you want is ammonium. With the 35, 32, 50, 50 ratio of ammonia was optimum for us. When you get into the higher yield and 250300 bushel yields, you want 75 to 80% of your nitrogen as ammonium and only 10 to 20% as the nitrate source of nitrogen. Because you want all of the photosynthetic that you can to go into the kernel. And if you have when the plant utilizes nitrate nitrogen and most plants can utilize either farm equally well. But it takes 15 to 20% of your Photosynthate to reduce nitrate nitrogen back to the amine farm so that the plant can utilize it. And so the higher your yield potential, the more ammonium nitrogen you want provide that those amino acids for that growth and your enzymes and everything. And the least nitrate nitrogen. We always found that there was a benefit to some nitrate nitrogen because it serves as a buffer both to limit the drain on carbohydrate. If you have a high uptake of ammonium nitrogen, nitrate will tend to balance that, suppress it down a little bit and but also as a stable form of nitrogen. If you run short, then you can use some of that photosynthe. If you have molybdenum and you have your other nutrients that are available to have part of the function of your nitrate nitrite reductase enzyme. Again you have a different physiological pathway. And sometimes if you're just saying, well I'm going to get most of mine from an ammoniacal source. You may forget that you also have to have libdenum for some of those other enzymes that aren't quite as dynamic or quite as involved as they are if you're relying more on the nitrate source. But those are some of the things that you could do to enhance that overall photosynthetic efficiency by just looking at farm of nitrogen. It's going to also influence your soil biology and your buffering capacity in those areas.

So Don, it's 1979. You're producing 350 plus bushels of corn per acre in a biological or biological soil ecosystem. Today it's 2017 and growers are struggling to produce 250 bushel. We don't even have a conversation about growing 350 bushel corn on a commercial field scale. There are a few notable exceptions, but not on a large scale production system across the board. What happened with that knowledge? Where did it go or why? Let me ask the question a little bit differently. Why was it not adopted on a much broader scale?

We started saying we have too much production. We need to focus in different areas. Our land grant universities that were established a lot of that research and especially for your long term commitments that a breeding program requires for each expression of that genetic potential. Those programs were closed out and materials were just given to the private companies to develop your experiment stations. We're happy to not have that long term commitment. They could then respond to the political pressures and your program started being limited three to five years through the competitive grants programs on a federal scale. And most of our breeding programs were funded through the Hatch Program Smith Lever Program that would give the states a constant amount of money on a formula basis. Are those long term agricultural developments that are the reason why we have the success in our agricultural programs today build on those long term continuous programs that were pretty much abandoned as we started looking at the bells and whistles in science rather than looking at the end product that we desire. Again, we were producing more than we knew what to do with. I don't know what would do with all the corn that we currently produce if we weren't producing so much alcohol. I mean that's the way to use your. Use your crop, find a new market for it. Certainly population growth is a long way from requiring what our current production is and is. Paul Wagner and his Cash Bulletin and with the group that he had, he worked with showed that we could produce enough food for about 15 billion people with about 30% less land if we wanted to really do that, really needed to do that with the technology that we had in 1964. But like you say, we were shooting for 400 bushel in, in 1980, 79 and 1980 and now we're struggling with 250 bushel. But sometimes you have to reinvent the wheel because that part of the system was not considered important and the resources were transferred. In a breeding program, you don't just turn it on and off with each little whim or political idea that comes along. It's a long term program. When we turned all of that material over to the private companies, their interest was the bottom line. So there's a tremendous amount of material that could be manipulated. But as far as that long term commitment, there hasn't been any of that. Genetic engineering has certainly not improve the long term effect because you get the idea that we can do it all in a laboratory by just switching this system on or inhibiting this particular system. We forget that it's still a system, an ecology that has to be managed if any of that's going to be of any value to it. And it's a thought process that's involved as well as the necessity, but also the desire, the innovation drops out when you forget that you're a part of, part of a very dynamic, beautiful system that was all put together and you start only focusing on one thing and silver bullets and forget that silver bullets may take care of a varmint, but they don't provide stability in the system.

Yeah, Don, what is something you believe to be true about modern agriculture that many other people don't believe to be true?

I don't know. I think everything I believe to be true is there are a lot of people that feel the same way. They may not be quite as outspoken as I've been. I think again when you focus on just one item and forget all of these systems work together, you automatically compromise your potential. And sometimes we have to realize that you have to make a few mistakes in order to do that. We're making plenty of them now. I think maybe that's part of the gray hair that I carry around with me that gives me that. I also see a lot of light at the end of the tunnel. The tremendous damage that we're doing to our children. Really hurts to think of your grandchildren having a shorter life expectancy as CDC has stated, than I have, than my potential. But it doesn't have to be. Sometimes we have to smash our thumb to realize that. Maybe you needed glasses to find a nail, but you have to you have to again refocus. I think your program is an excellent program. You're successful in communicating a lot of the importance of managing the system rather than just looking at the bottom line that happens to. That look very fascinating to us right now are very easy for us. Looking at putting it in perspective is what we need to do. And I see some young people that are able to express that a lot better than I am. You're one of those that I admire, have a great deal of confidence in and the ability of you to get that job done and fall.

Thanks for saying that. It's all that I've learned and I've been able to communicate are things that I've learned from a wise elder such as yourself. So it's really a big thanks to you. Don, what do you see as the biggest opportunity in agriculture today?

Reinventing the wheel. Reinventing the wheel.

Reinventing some of the things we've lost.

The greatest need anyway is getting back to nutrient density and eliminating the pesticides, especially the glyphosate, which is, you know, you put it on a 0 to 100 scale and glyphosate from Chuck Benbrook's research at Washington State shows that it's. It's on a scale of about 82. All other pesticides together, other than the nicotinectinoids, which would be at about a 14. All of the other pesticides together from a health standpoint are less than 1.

Wow, that's incredible. I was not aware of that.

We focus on a lot of those that are in that less than 1. Not that we shouldn't, but we totally ignored the one primary material that is doing the great health and an environmental standpoint. And that's because it's not just a pesticide per se, an antibiotic. It's a strong mineral chelator. It has the ability to essentially disrupt everything that we value in our ecology and our own subsistence and that needs to be removed from our soil because. And from our food, especially because of that wide scope of. Of damage that it's doing. I'm not opposed to tools in agriculture and making things easier. I never could find a hoe that I felt was really designed to fit my hand. That wasn't my father's decision, but that was my concept of what that hoe should be. I can remember when 2,4D was available to us after World War II and what a tremendous tool we thought it was. But it also requires some common sense and some recognition that we don't have silver bullets. We have an ecology that we need to manage. And if we manage it effectively it will serve us for the eternities. If we don't then we have to go through correction phases that can be very painful for us. Self fulfilling prophecies of food shortages and that you look at the recent elections, you see the change in the German government that took place. Quite a surprising change for many people took place because of agriculture. And you can go through history and show how important agriculture is. It's a basic infrastructure of any society and when we follow that there are consequences and it requires a correction in that manner. And I think we're seeing the pendulum swinging now so that we're recognizing the need for nutrient density, the need to eliminate a lot of the exposure that we have to the glyphosate and some of the other chemicals that have been accumulating in our environment and in our food supply. I see that pendulum swinging. I think it's going to. We'll see those changes taking place not as fast as I'd like to but like to see but they're coming and I don't move very fast either. So can't necessarily complain in those processes. Critical that we recognize our stewardship that we have when it comes to the soil and to our own survivability in these areas rather than just accepting the changes that we that have occurred and say well there's nothing we can do about it now. Well there's a tremendous amount and matter again of understanding that we're managing inequality, that we're a part of that and great opportunities for us to do things better.

Yeah. Don, what are some books or some resources that you would recommend to growers?

They want to learn more and well, you have the Phytopath Society under the direction of Lawrence Danoff kind of provided the nudge to keep us going and that burr under our saddle. But I have a number of resources. In American Phytopath published the Green book on mineral nutrition on plant disease. At your interested in the relationships there. I think that's a good book. I'll plug it. I'm one of the editors on it. I don't get compensation for that. You have Marshner's book certainly is probably the bible in plant nutrition on mineral nutrition of fire plants. It's a little detailed or a little deeper than a lot of people want to go. You have a lot of the older books, the Albrecht system you have. They're just a number of resources if a person really wants to make the changes. You have your programs that you're working up, you're able to communicate with the growers. I think you see eight or ten different systems now looking at nutrient density, how do we measure it, how do we define it, but at least getting a lot of that background information that's necessary for us to really make the application. Overall, I think that George Romney, when he managed to get the Constitutional Convention put together for the state of Michigan, had the opportunity of serving in that process. But he made the comment once that science can lead to progress. This is paraphrasing. It can lead to progress. We recognize that with each scientific accomplishment there some unintended consequences. And we also deal with the unintended consequences, then we'll see that continuing plateauing, growing for us, increasing. If we don't recognize that science is merely a tool that we have and we rely solely on it without recognizing that there are unintended consequences, then it can come back and bite us pretty hard. And I think that's what we're seeing in the our general adoption of genetic engineering. Without recognizing the unintended consequences that are built into that system, either from a mutation standpoint or direct damage that is done, then there's a reckoning process that we'll all have to go through. We're going through it now. If you look at the health consequences, all you have to do is go to a cancer tumor center or are doing child development center, go to a maternity ward and see what the birth defect that we're seeing now are becoming so prevalent that you can't ignore them. So we're probably in that reckoning stage and at a time when it becomes important that we start looking back in the box rather than just outside the box for those solutions that we need for society.

Don, what is a question that you wish I would have asked?

I don't know. I've been gabbing so much that I haven't been thinking about what you should ask. I think you asked some questions I hoped you would. I gabed up may not have given you time to do those, but I think certainly from the topics that we've been on today, I didn't get into the GMO glyphosate that kind of takes us a little different direction. Very critical when it comes to nutrient density because of its impact on the soil ecology as a whole, our entire ecology because it's such a strong mineral chelator as well as that antibiotic effect. And the antibiotic effect may be of greater damage than just the direct elation. Now it's an antibiotic, broad spectrum antibiotic because it's a broad spectrum chelator, but those areas. But I'm really happy to see a lot of the emphasis coming back to soil ecology, the role of different crops and the rotation or in the overall cropping system, the use of COVID crops. I'm really excited to see that that's something that 60 years ago when I started in plant pathology and looking at the effect of crop residues and crop sequencing on the soil borne diseases and well, there's got to be a better way than saying, well, you can only grow an economic crop or your primary economic crop every eight years because the disease pressure is going to build up on you to the point that it's not going to be economical. And we could demonstrate that very easily back in the 1950s and 60s what those effects were. But then in the remediation aspect or maintaining the balance in that soil environment, the fact that 85% of that effect is the immediately preceding crop means that you can do essentially everything that we were doing in a five or an eight year rotation. And at the same time we're growing economic crop and even do better when we look at the improvement in supporting that growing crop from a nutritional standpoint, nitrogen or other minerals through the form of nitrogen that we can influence with that farm or with that particular crop for exudate. So I think those are really exciting. Other people don't seem to get quite as excited as I do. But it takes me back to those things that those questions that I had, well, how do we do this better? If these are things that we need to do from a biological standpoint, isn't there a way to compress some of that process and make it capitalize on the potential dynamics of it? Oh, we see the end product on a consistent basis rather than just the ups and downs that we would have otherwise. It's an exciting time to see what the next generation is doing, what they're looking at now, and you see it going both ways. Sometimes you have to do that in order to recognize how it fits back together.

I do agree that there are very exciting times and there are lots of new innovations and also as you described, lots of reinventing the wheel happening and those are good things. Don, thank you very much for joining us. I have enjoyed this interview tremendously and I'm sure our listeners will as well. It's been a tremendous honor to have you here and we look forward to possibly having you back in the future. Thank you very much.

Appreciate all you do and very honored to be a part here with you.

Thanks Don this podcast was brought to you by a great company that I work for and AEA, Advancing Eco Agriculture, the leader in regenerative agriculture since 2006. At AEA, we believe in challenging the status quo to find more profitable and regenerative ways to grow crops. We also believe that healthy plants are resistant to pests and disease, and that to grow healthy plants we must first think differently about agriculture, about empowering life instead of suppressing life, as about regeneration instead of degeneration. To achieve this, we formulate and sell products that help growers produce higher quality yield with less risk of crop failure. In short, we help growers make more money with less risk. Thank you for listening.