Insects are only attracted to unhealthy plants

An excerpt from the podcast interview with Tom Dykstra:

John: What do you believe to be true about modern agriculture that other people may not believe to be true?

Tom: Insects are only attracted to unhealthy plants.

If you believe that insects are attracted to unhealthy plants, your whole thinking changes on insects. Suddenly you have no use for insecticides. It just follows with that level of thinking, because you realize, “Well, I’m not competing with insects. They’re just eating some of the garbage plants that I shouldn’t be eating. So I really don’t need to spray them anymore.”

So now all the organophosphates and synthetic pyrethroids and carbamates and neonicotinoids—they’re all unnecessary. As you reason through this, that’s one of the conclusions you come to. You have to come to it when you believe that insects are only attracted to unhealthy plants. I don’t even have to come out as an anti-pesticide guy. I can simply say that insects are not attracted to unhealthy plants. And by extension, I would say, yes—insecticides are unnecessary.

Under specific circumstances, they have their role. I will be the first to admit that I’ve had fire ants. Sometimes they come into the house. I do have a Raid can in my house. And we have had situations where the kids would leave food crumbs around. And the situation has to be taken care of. So I’m not afraid to use insecticides, and I understand that they have their place.

However, having said that, when I’m raising crops I’m never spraying it with anything.  I don’t have a knowledge of all the insecticides, but I don’t use any of them. I’m not using any herbicides or fungicides. I use insects as indicators. I go out and check my corn plants, for example, and I look to see if they’re being attacked. And if they are, I determine what insect is attacking them, and I figure out why they aren’t healthy.

For example, the first time I started planting corn, I did have a few insects that were attacking it. By the third time that I was planting corn, no insects were attacking it, but deer came in and cleaned me out. This is the difference between the insect digestive system and the mammalian digestive system: we have a higher-level digestive system. We can handle healthy food. The deer are more interested in healthy crops. They’re not going to go after unhealthy stuff. They’ll leave that up to the insects.

Managing soil borne pathogens

For soil-borne pathogens, there is no correlation between the presence of the organism in the soil and the expression of the disease in the crop. Infections severe enough to produce crop loss are correlated with the absence of suppressive organisms more than the presence of the pathogen.

Soil colonizing organisms are usually dependent on crop residue for nutrition and generally have higher nutrition requirements. Soil inhabiting organisms have much lower nutritional requirements and remain present in the soil more or less constantly.

Both groups can be effectively managed with cultural management practices to prevent any infections from occurring. From the podcast interview with Don Huber.

John: 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 management tools: crop rotations, using cover crops, tillage, the impact of moisture, etc. Earlier you spoke of the differences between soil-borne pathogens and soil-inhabiting pathogens. It’s fairly well understood that we can use crop rotations to manage soil-inhabiting pathogens. Are you suggesting that it’s also possible to use these tools to manage and suppress soil-borne (colonizing) pathogens?

Don: Very definitely. Most of our soil-borne (colonizing) pathogens have very limited genetic resistance. We rely on those management techniques to control them. Sometimes we don’t recognize it as much as we need to, but soil-borne pathogens have a much more limited relationship as far as population dynamics. We may measure the population of spore load and other things for organisms like Fusarium, but the organism is there in 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.

Soil colonizers colonize only as long as they have a nutrient base to function with. So we can either extend the time between susceptible crops—which we typically do with most of our potato pathogens, for instance—we see them building up in two or three crops and we want to break that population down. Same thing with anthracnose on corn. It’s a soil colonizer. Cephalosporin on wheat. All of those organisms survive in the residue. Many of them even produce an antibiotic, so they slow down residue degradation to extend their lifetime in the soil—so that other organisms aren’t able to colonize that food base.

This is quite different from Rhizoctonia or Fusarium—many of the Basidiomycete-type pathogens are very excellent soil inhabitants. They don’t require the base of nutrients that many of our colonizers do.

Seeing our product as eaters see it

Do you spend time thinking about how eaters percieve what you grow? Or your buyers? Matt Kleinhenz believes this is a critical skill.

John: Obviously, you’ve thought about this a little bit. If you believe that growers are underappreciated, which I absolutely agree with, have you given any thought to how that might be remedied?

Matt: Not to share an unpopular idea, but I think they need to ask more of themselves. I also think that they could benefit from being a bit more assertive, professionally, about what they do—how and why, and what role they play. Some people will become activists, some people will become involved in grower organizations, some people will keep it one-on-one and simply have excellent conversations with their buyers on Saturday mornings or whenever they happen to encounter them—all of which are necessary.

But on the whole, I would encourage folks to use the opportunity to display their understanding of the farm’s role and of food’s role in that person’s life. Because too many of our eaters more or less just eat to avoid being hungry, right? Which is entirely fine. It’s a choice. Others, though, look to food for other types of return on investment; it’s an enjoyable experience. When a grower encounters a person or a market that might be wired that way, that might be thinking of food differently—having higher expectations of it, ideally—I’d like the grower to be able to step up and say, “Yeah, this is what we do and how and why, and we have data.”

Growers should have a real foundational argument for whatever assertion they would like to make. But a lot of growers, understandably, are on the farm doing their thing; being out and about and mingling with the masses is not necessarily their forte or interest. But there are other ways of having an impact and playing a role.

John: I completely agree with what you’ve described. The growers who have been able to really make an impact with consumers and with eaters are those who communicate “why.” They communicate why they make the choices they do. There certainly is an element of describing what they do and how they do what they do. But I think the most important piece, which resonates most deeply with eaters, is describing why you need to make these various decisions and these various choices that the consumer may or may not necessarily agree with. When you describe the situation of what’s happening and why you need to make these choices, their appreciation for the challenges and the difficulties and the opportunities in agriculture completely changes.

Matt: We want to be careful here. We want to elevate as much as possible the position of the grower within the whole spectrum of our society and our culture, and we want them to be successful. Thinking more about your question, the single most common source of struggle I’ve seen over the years is the grower looking at their product only as a farmer—being unable to see it in a more comprehensive way—most especially as the buyer sees it. Attitudes like, “Well, if I eat it, everyone else should be able to eat it too.”

When a grower is able to see the product from completely the other side of the table, as they—as much as possible—shed their grower attitude temporarily and see the product as if they’re buying it, for how it’s going to be used by the buyer, then they’re on a really exciting path. Then they can look differently at their own farm and possibly be able to exploit market opportunities that they didn’t see before.

That’s the single most consistent aspect of a vegetable farm now—especially a vegetable farm that might be selling directly to consumers, but even those who grow for processors.

John: That’s a fascinating observation.

Matt: They need to see it as the buyer does, and unequivocally so—without reservation, not kicking and screaming. They need to welcome the opportunity to see the product as the buyer does. You will return to being a farmer—no worries! But when you return to being a farmer, hopefully you carry that experience of seeing the product differently with you. All of a sudden, for some, it will be like, “Actually, I’m not producing kale; I’m producing food that someone’s going to serve at a family function, and it’s got to be just so.”

We do these exercises with students in the class where I hand them a tomato, or I hand them a potato, and I say, “Tell me what you see.” And everyone looks at me funny. You’d be amazed by the kinds of words that are used to describe ordinary products. But then we’re on a path towards understanding what that tomato is. If you go through that same exercise, for example, like I have, with students in the dietetics nutrition arena, versus the students in the agriculture arena, it’s amazing how they look at the same thing and use different words to describe it.

For a grower to understand how others see the product is indispensable.

2020-05-20T06:01:07-05:00May 22nd, 2020|Tags: , , |

We can produce enough food to feed 15 billion people with 30% less land with 1960’s tech, if we want to.

This quote from the podcast interview with Don Huber is powerful and important.

We were shooting for 400 bushels in 1979 and 1980, and now we’re struggling with 250 bushels.

John: Don, in 1979 you were producing 350-plus bushels of corn per acre in a biological soil ecosystem. Today, growers are struggling to produced 250 bushels of corn. We don’t even have a conversation about growing 350 bushels of corn on a commercial field scale. There are a few notable exceptions, but not on a large-scale production system. What happened with that knowledge? Where did it go? Why was it not adopted on a much broader scale?

Don: We started saying we had too much production. We needed to focus on different things. At our land grant universities, a lot of that research and the long-term commitments that breeding programs require for the expression of that genetic potential was closed out. Materials were just given to the private companies to develop their experiment stations.

The universities were happy to not have that long-term commitment. They could then respond to the political pressures, and their programs started being limited to three to five years—for the competitive grant programs on a federal scale. And most of our breeding programs were funded through the Hatch Program and the Smith-Lever Program, which would give the states a constant amount of money on a formula basis for those long-term agricultural developments, which are the reason why we have success in our agricultural programs. They were built on those long-term, continuous programs that were pretty much abandoned as we started looking at the bells and whistles in science rather than at the end product.

Again, we were producing more than we knew what to do with. I don’t know what we’d do with all the corn that we currently produce if we weren’t producing so much ethanol. I mean, that’s the way to use your crop: find a new market for it. Certainly, population growth is a long way from requiring our current production. We could produce enough food for about fifteen billion people with about 30 percent less land—if we wanted to really do that, if we really needed to do that—with the technology that we had in 1964.

We were shooting for 400 bushels in 1979 and 1980, and now we’re struggling with 250 bushels. But sometimes you have to reinvent the wheel. That part of the system was not considered important, and the resources were fractured. 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. 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 certainly has not improved the long-term effects; you get the idea that we can do it all in a laboratory just by 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 it’s going to be of value to us. 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 a very dynamic, beautiful system that was all put together—when you start focusing on only one thing. Silver bullets may take care of a varmint, but they don’t provide stability in the system. 

2020-05-19T19:18:25-05:00May 20th, 2020|Tags: , , , |

Livestock profitability exceeds commodity crops

John: Many people are beginning to recognize the value and the importance of cover crops, but there’s still a lot of hesitation around incorporating livestock into agricultural ecosystems. In your estimation, how important do you believe it is to incorporate livestock to the overall ecosystem?

Gabe: Let’s step back and take a look at how our soils were formed. They were formed over long periods of time by large herds of elk and bison being moved across the landscape by predators—trampling, grazing, and then defecating and urinating. A natural nutrient cycling occurred. The animals moved on, so there were long periods of rest and recovery, which allowed for a maximum amount of carbon to be pumped into the soil. Soil health revolves around a carbon cycle.

That’s how our prairie soils were formed, but look what we’ve done with our modern monoculture-type mindset. We’ve removed the diversity, and we’ve removed the animals from the landscape, and now we’re simply not pumping as much carbon into the soil. Now, can we advance soil health without livestock? Absolutely. I have several quarters of land that we’re just not able to graze livestock on because they’re surrounded by housing developments and there’s no water; it’s just not worth the hassle to incorporate livestock onto those acres. We’ve still significantly advanced the soil health on those acres, but those soils will never reach the health of the soils where we are are able to graze livestock.

There are many benefits of having livestock on cropland. The one thing I think producers are really missing out on is the profitability of doing so. I ran some numbers after 2016 and we added $220 net return per acre on the cropland acres where we were able to graze livestock. With margins where they in commodity agriculture today, that’s significant. What producer doesn’t want $220 more per acre? I’m not saying all producers will want to do the things we’re doing with livestock; I’m just saying that they’re missing a major opportunity there.

Cover crops are an absolute no-brainer from a soil health standpoint. If you can integrate livestock, that’s a way to convert those cover crops into dollars. I tell producers that even if they don’t want to do it, there are many people in their communities around the country who would love the opportunity to run some livestock—to enter agriculture that way. Why not benefit your land, help a young person, and integrate some livestock under your cropland?

John: That’s a great idea for including the next generation. When you talk about the economics and the profitability, an additional $220 net per acre—isn’t that a larger net than most growers are getting producing corn?

Gabe: It is. On our operation, we sell very few commodities. We’re doing value-added, direct-to-consumer products—simply because of the dollar return we can generate by doing so. I just shake my head at commodity agriculture today. I have no desire to produce commodities, and I really don’t understand why people do it. There’s just no money in it, unless there’s a major drought somewhere or some external force. We tie our hands, so to speak, when we produce commodities.

I’m not a proponent of the current production model. I think it leaves too many decisions in hands other than our own. Our farm is profitable every year because we set our own prices. We take that out of somebody else’s hands and put it in our own. When you’re able to do that, that really adds to your bottom line and increases profitability significantly.


2020-05-05T05:17:19-05:00May 15th, 2020|Tags: , , |

How the form of nitrogen influences disease suppression

Nitrate and ammonium nitrogen have dramatically different impacts on soil biology and possible pathogens. Some pathogens are enhanced by nitrate and suppressed by ammonium. Others are the exact opposite. Most (but not all) soil-borne pathogens are enhanced by the presence of nitrate. This corresponds to the impact of reduced vs oxidized environments, since ammonium is the reduced form of nitrogen, and nitrate is the oxidized form of nitrogen. In general, reduced environments are very disease suppressive, and oxidized environments are disease enhancing.

I have had many discussion about this topic with Don Huber, inlcuding this one on a podcast interview.

John: What are the impacts of nitrogen and nitrogen applications on developing disease-suppressive soils?

Don: Most of your soil organisms are hungry for two things. One of them is nitrogen. The other is carbon. When you change either of those nutrients, you see tremendous stimulation of a lot of organisms in the soil, depending on what your source of nitrogen is.

One of their primary pathogens on a lot of vegetable crops in Florida is Fusarium oxysporum. It’s a vascular Fusarium. Growers can get pretty much complete control by using nitrate nitrogen and calcium. If they can stimulate nitrification, or if they apply nitrate nitrogen, potassium nitrate, or calcium nitrate—and also use some liming (lime = an oxidizer) to get their pH up—they have fairly effective control of Fusarium wilt diseases.

With tobacco, where we use fumigation to control some of the soil-borne diseases, you should have at least 30 percent of your nitrogen as nitrate nitrogen. If you don’t—if the plant is taking up all ammonium nitrogen—you can get into a carbon deficit because the plant detoxifies the nitrate or the ammonium nitrogen by combining with photosynthate from photosynthesis; that provides the carbon base for those amino acids. Then the nitrogen is translocated as the amino acid. If you don’t have enough nitrate nitrogen present to buffer against an ammonium source—if you’re going to get fumigation, because our soil fumigants tend to knock out nitrifying organisms—or if you don’t get nitrification there, it stabilizes in the ammonium form. It can be a drain on the carbon and the energy availability until that ammonium is detoxified and utilized by the plant.

John: I’m thinking about your description of how many soil-borne pathogens—soil-borne fungi such as Fusarium 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?

Don: On that group of pathogens, you will see a tremendous reduction in disease—with the ammonium nutrition. I wrote a chapter in one of the annual reviews on the impact of the form of nitrogen. You’ll see a tremendous benefit in different organisms by the form of nitrogen that the plant is predominantly supplied with. If you modify the environment so that those soil microorganisms make those conversions, you’ll see that the form of nitrogen will be available for the plant.

So, it’s important that you have both the management tools as well as the form. Most of our soil’s nitrification takes place very rapidly, so you need to do something to inhibit nitrification. We can do it biologically—we can modify the speed of that reaction so that we can increase the amount of nitrogen in nitrate or ammonium. When it’s taking ammonium nitrogen, you have a reducing environment. That reducing environment is favoring manganese-reducing organisms so that there will almost always be an increase in manganese availability for the plant—when you predominantly use an ammonium form of nitrogen. The more rapid, oxidative form is the nitrate source of nitrogen.

Should consumers pay more for quality?

Many growers are eager to be compensated for the quality of the food they produce. To be compensated for quality means that quality needs to be quantified and measured. The idea of compensation also begs the question, should premium quality be marketed at a premium price, or should it be universally accessible? Should all produce be required to meet minimum nutritional quality thresholds?

I had an interesting conversation with Matt Kleinhenz on this topic in this podcast episode.

We should continue to focus on how a farm can become an instrument of public health, producing a more nutritious product, a more nutrient-dense product, a more flavorful product—a product that is more desirable to eat, simply because of its chemical, biological, or physical properties.

John: I’ve recently been a part of a number of conversations where growers are expressing the desire to improve nutritional value. Sometimes they use the language of “nutrient density” to talk about the improved nutrient density of food. My observations have been that for the most part, consumers and buyers at this stage aren’t really having that conversation—at least not on a large scale. An appropriate analog that they might be looking for would be flavor and aroma. But what have you observed? Do you think there is the potential in the future to have a major market demand for “nutrient-dense” foods?

Matt: Perhaps. First of all, nutritional value, or nutrient density, is a significant passion of mine, and I know it’s a significant passion for other investigators that I work with. Some of them are not in the so-called public light as an extension person, or as a grower/advisor, but they are working tirelessly and quite impressively towards a similar goal, but within their lane, regarding understanding what nutritional value is and how it can be enhanced. It is a big passion of mine.

To the second part of the question, I think we need to be very specific when we talk about the nutritional value and nutritional density. It’s a complex topic, and we don’t wave our hands and say that just because it’s complex that we can’t understand it, or that we shouldn’t approach it. No, quite the opposite. We should stay on task. We should continue to focus on how a farm can become an instrument of public health, producing a more nutritious product, a more nutrient-dense product, a more flavorful product—a product that is more desirable to eat, simply because of its chemical, biological, or physical properties. These are all parts of the process of enabling the food that we offer folks to play a larger role in maintaining or enhancing their quality of life, especially through their health status.

To the final point—will there be a market? Will there be a time when more people are paying more attention to this aspect? I think so, but we’re not there yet. I think that interest already is strong within a small community of eaters or a community of buyers. Where there are these so-called beachheads, there can be growth. Here in 2018, one-half of one percent of people might make decisions around nutritional value; some year down the road we might be able to say it’s 5 percent or 10 percent. In that increase there will be so many opportunities for enterprising growers to be a part of that process; it will become that much more noticeable

Nutritional differences in insect susceptible plants

Healthy plants are completely resistant to insects.

We have observed this to be true in the field on many occasions. Over time, more connections come to light describing the scientific reasons for how this occurs.

Larry describes their pioneering research seeking to identify the nutritional differences between insect resistant and insect susceptible crops in our podcast episode here.

So, if you have an imbalance—if you have too much nitrogen relative to potassium—what happens is you get the buildup of free amino acids in those plants. And insects love free amino acids. They’re a very digestible source of nutrients for them because they’re also highly limited by nitrogen.


John: With some of the original research that you did—comparing the insect pressure on the organic farms versus the nonorganic farms—this is actually something that I often hear from organic growers, but I haven’t uncovered a lot of research where people have actually tried to do a comparison and evaluate the differences. What were the differences that you were seeing? What really stood out for you?

Larry: Again, keep in mind that this was twenty to twenty-five years ago. There’s been a lot more research in organic systems now. But at the time, organic farming was considered very unscientific, and more New Age, and not amenable to large-scale production. And so I was working with a lot of organic farmers who were basically doing their own research—not necessarily replicated research as we would do at the university, but trying different things and seeing what worked on their farm. This is the context in which we got started.

I actually received a lot of criticism at the time—that what I was doing was not very productive, or not the direction I should be going as a non-tenured faculty member. So, we went to these organic corn and soybean farmers, and the ones we worked with had animals integrated into their system as well. First of all, we just did a census of their corn, looking at the levels of European corn borer damage in their fields versus their conventional neighbors. And, as I’m sure you and many of your listeners have often heard, I kept hearing this idea that if we have healthy soil, then we’re going to have a healthy plant and that insects don’t like healthy plants—that’s why they don’t see the damage.

Although that in itself is not a very scientific statement, we could reformulate it as a hypothesis that we could test empirically. And so we collected soils from these organic farms and then went right across the street to a conventional neighbor, collected their soils, and brought these soils into the greenhouse and planted them to corn. And we fertilized each of them either with an organic fertilizer, like manure or compost, or with a chemical fertilizer.

What we were interested in figuring out was, first of all, whether the insects could tell a difference in these plants. And if they could tell a difference, was it associated with that short-term effect of the type of fertilizer we used or that long-term effect of that history of management and how that impacted the soil community. And so, after setting these plants up and letting them grow to a certain stage, we released European corn borer females that had been mated into the greenhouse. All of this was replicated and randomized.

And we just let them loose to see where they would lay their eggs. And what we found very consistently—we actually repeated this experiment, I think, with four or five different pairs of soils from farms—was that if the plants were growing in a soil from an organic farm, irrespective of the fertilizer we applied, they received relatively few eggs. Whereas if the plants were growing in a soil from a conventional farm, sometimes they would receive a lot of eggs and sometimes they would receive only a few eggs.

This gave rise to this concept that I call biological buffering. The way we envision this—and this was our working hypothesis—was that in those organic systems, where you have a recurring influx of organic matter into those soils, either in terms of cover crops or plant manures or animal manures, you create this soil community that is beneficial to the plant. And when nutrients then go into that system, they get absorbed by this microbial community and then they release those nutrients very slowly over time. As a result, we hypothesize that those plants are in better mineral balance than when you’re putting down high levels of nutrients.

Why this would be important is because plants are almost always limited by nitrogen levels. They don’t have mechanisms for dampening the levels of nitrogen that they take up. They’re going to take up whatever they can get. And in this context of putting down inorganic, highly soluble nitrogen sources, often these plants are taking up much higher levels of nitrogen than they are really set up to deal with.

We then hypothesized that in this situation, those plants would tend to accumulate the simple compounds. When you have an imbalance of nutrients—let’s say nitrogen and potassium—if you think about those two elements, nitrogen is of course very important in terms of protein synthesis and potassium is important in terms of converting amino acids into protein. So, if you have an imbalance—if you have too much nitrogen relative to potassium—what happens is you get the buildup of free amino acids in those plants. And insects love free amino acids. They’re a very digestible source of nutrients for them because they’re also highly limited by nitrogen.

In situations where you have these imbalances, that plant becomes very nutritious for the insect; whereas in the plant that is in better mineral balance—one that’s getting its nutrients relatively slowly—that metabolic machinery of the plant is able to act more efficiently. As amino acids and sugars are produced in the plant, they are more immediately converted to the less digestible and more complex building blocks of the plant, like proteins and starches and cellulose and that sort of thing.

Untapped yield potential on corn

How much can you increase photosynthesis levels beyond what is considered ‘normal’ today? Beyond what is common?

How much higher might national corn yields be, if the right incentives were aligned to produce the desire for higher corn yields? Could we have a 350 bushel national average yield? Don Huber suggests we had the capacity to do so with knowledge that existed in the 70s if we had the collective desire.

From our interview on the podcast episode here.

John: What is the potential for plants to increase the volume of photosynthesis?

Don: The potential is 100 percent. I mean, fivefold, tenfold—depending on where we are now and what plant we’re talking about. There a number of different ways to do that.

I mentioned plant morphology, but you can also do it by increasing light intensity. You got a lot of leaves on a garden plant—a mature corn plant at tasseling time—that aren’t getting very much sunlight. They’re not photosynthesizing at their potential because of that lack of sunlight. That’s where morphology comes in.

Plant spacing—we can increase the number of ears on a corn plant. There is tremendous work being done at Purdue, for instance, in corn breeding/genetics—they’re producing five and six ears on a corn plant. If you increase the efficiency of that plant, you don’t need as high a population. You can minimize that crowding and that shading effect.

We can reduce the allelopathic effect of our plants. To increase the population in corn, it’s very critical to have even germination. If you delay germination six to eight days, you automatically reduce the size of your ear by the allelopathic effect—that auto-intoxication effect of the root exudates on an adjacent plant—by as much as 80 percent.

John: Wow!

Don: When the John Deere MaxEmerge planter came out, I remember how it was almost an instant success because it increased the soil-seed interface—the contact that gave you that uniform emergence, to minimize that allelopathic auto-intoxication suppression that you otherwise had from those higher populations. We got an increased corn population and maintained full yield potential without the allelopathic chemicals reducing the overall production potential of that particular plant.

There a number of things we could do if we needed to. Right now we’re concerned about a surplus. The biggest thing is that necessity is still the mother of invention. But there’s plenty of potential there.

In one of our brainstorming sessions at Purdue we asked Charles Tsai what the biochemical genetic potential of a corn plant was. And a couple of weeks later, when we were all together, he said “I’ve got your answer.” We were shooting for 350, 400 bushels in our research. We knew that a lot of our better farmers—back in the late ’70s—had the potential for 550 or even 600 bushels. 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 600 bushels a realistic figure?” And he said “You’re all pessimists. The biochemical genetics of the corn plant are about 1100 bushels.” That’s what we could do if we managed the 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. The limiting factor is the innovation of man. And as long as we’re doing okay—as long as we don’t have that burr under our saddle to look at both the genetics and the environment—we won’t have the need to maximize the expression of that genetic material.

John: What yields did you end up achieving on your yield trials?

Don: We could get 400 bushels. We had farmers that were getting 350. Of course, the average was still 75 bushels. They were doing three or four or five times what the average was on a major piece of land. They were able to do it because they recognized that they were managing an ecology. They started out with the soil. They had a beautiful soil.

I remember visiting Herman Warsaw’s farm. 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 very well. In some of his neighbors’ fields you’d get the probe down three or four inches and you’d have to really put some pressure on it. To get it down a foot and a half you’d be driving it in.

I can’t tell you how many of the old ping tubes are still sitting out there in the field. Those were tubes that you could drive into the soil to collect soil samples—at three and four feet. And we had to get it into our soils using a sledgehammer. Then the problem was pulling it out. You would tear the metal off of the tube with a jack, and finally you’d just crimp it over so that it wouldn’t tear up the tire, and then you left it. A lot of them are still sitting out there in those fields because we didn’t have that concept— the soil wasn’t a major part of the management program. In general, we would look at the nutrients and forget that all parts of the ecology needed to be managed—to have better percolation, to have biology, to have air exchange—and most things have to take place if you want to capitalize on the genetic potential of the plant.

John: What were the plant populations that growers were using to achieve 350-plus bushels per acre?

Don: You had the old Pioneer 3532 seed—a hybrid that picked up 95 percent of its nitrogen by tasseling time and then merely recycled it. On sandy soils it was a great hybrid because you couldn’t maintain your nitrogen availability in those sands. It would take it up and store it, but it had a yield potential of about 125 bushels 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 exudate with high population. It had a fixed ear. So, as you increased the population, you still maintained that same ear length. It wasn’t big like your higher-yield hybrid, but it was very stable and it tolerated high populations. So they got the yield up by increasing population.

With our other varieties—our high-yielding varieties that were hybrids—there you had a flex ear that related to the environment more dynamically. The higher the yield potential, the more nitrogen you want as ammonium. For the 3532 variety a 50-50 ratio of ammonium/nitrate was optimum for it. And you get into the higher yield and the 250- to 300-bushel yields, you want 75 to 80 percent of your nitrogen as ammonium and only 10 to 20 percent as the nitrate source of nitrogen, because you want as much photosynthesis as possible to go into the kernel. When the plant utilizes nitrate nitrogen—and most plants can utilize either form equally well—it takes 15 to 20 percent of your photosynthate to reduce nitrate nitrogen back to the amine form so that the plant can utilize it.

And so the higher your yield potential, the more ammonium nitrogen you want—to provide those amino acids for that growth, and your enzymes and everything—and less 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 carbohydrates—if you have a high uptake of ammonium nitrogen, nitrate will tend to balance that—but also as a stable form of nitrogen. If you run short, then you can use some of that photosynthate.

If you have molybdenum and your other nutrients available, you have part of the function of your nitrate and nitrite reductase enzymes. Again, you have a different physiological pathway. And if you’re saying, “Well, I’m going to get most of mine from an ammoniacal source,” you may forget that you also have to have molybdenum 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.

Those are some of the things you could do to enhance that overall photosynthetic efficiency—the form of nitrogen is going to influence your soil biology and your buffering capacity in those areas.

2020-04-25T14:20:06-05:00April 27th, 2020|Tags: , , , |

Eliminating the need for fertilizers with a larger root zone

A common theme from many pioneers in the regenerative ag space is that you can develop soil biology to the point where you can eliminate fertilizer applications and maintain or even increase yields. Here is Michael McNeill’s perspective on the possibilities.

From the Regenerative Agriculture Podcast with Michael McNeill:

John: We’ve been talking about a number of different things that you seem to have a very different framework on. What are some things you believe to be true that many other people don’t believe to be true?

Michael: I believe that the soil can grow an extremely healthy, high-yielding plant with minimal additions of inputs. There are plenty of minerals in the soil if you treat it properly. I think most people would disagree with me on that. They have “proven” that you have to put on fertilizers to get good yields.

John: Wow.

Michael: I’m going to stick with that, because I’ve proven it to myself—that you can do that.

John: So you’re saying that you can actually grow healthy, high-yielding crops without adding fertilizers?

Michael: Yes.

John: How do you do that? How does that work?

Michael: That’s a complex question with a very complex answer. But the key is creating healthy soil that allows plant roots to go deep into the soil, to extract the minerals they need. There’s a vast sea of minerals that are available. If you’re starting to see suppression of crop yield, and then you add fertilizer, and the yield comes back—that’s because you’re only using the top few inches of the soil. The roots are not healthy enough to penetrate deeper—to actually mine the minerals that are there. Our soil is nothing but minerals.

John: This is something that I’ve talked about as well. And the question that I often get is, “Aren’t you going to deplete the soil of minerals if you’re not adding fertilizers?”

Michael: Well, my quick reply to that is, “Try and take all the salt out of the ocean.” You can deplete minerals in a rooting zone—I’ll grant you that. But what you need to do is expand your ability to search in a bigger rooting zone. And you need to add mycorrhizae into that equation, because you want a really big rooting zone. Let the mycorrhizae work for you.


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