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The problem, and large opportunity of manganese availability

Most agricultural soils today do not supply adequate levels of manganese to a crop. This is a foundational problem, because of the need for manganese in the water hydrolysis process at the beginning of photosynthesis.

When water is absorbed from the soil, and used for photosynthesis, the first step in the process is that the water molecule needs to split into H and OH, hydrogen and hydroxyl. This process is called water hydrolysis. Without this crucial first step, the photosynthesis process is blocked or greatly reduced. The water hydrolysis process is completely dependent on manganese to function. The macro ingredients needed for photosynthesis are chlorophyll, sunlight, water, carbon dioxide, and manganese. Even if we have generous levels of the first four, when manganese is low, it becomes the bottleneck that slows down the photosynthesis process.

We observe inadequate manganese levels in plants almost universally. You can observe it visually, quite easily in most plant species. The leaf vein should be at least as dark green as the area between the veins. When the veins are lighter in color than the area between the veins, this is an indicator of a low-level ‘hidden hunger’ manganese deficiency, and manganese being a limiting factor in the photosynthesis process. You can observe this easily on most plants, crops, cover crops, and so-called ‘weeds’.

I have learned from experienced agronomists that this systemic challenge with manganese has not been present historically. We now know that glyphosate, AMPA, some other pesticides, and oxidizing microbial communities all contribute to manganese being chelated and oxidized in the soil, and not available for plants to absorb. Many soil have generous levels of manganese in the profile, it only needs to be released. I will be hosting a webinar on Friday June 19th at 11 AM EDT describing the cultural management practices and tools that can be used to release the locked up manganese in the soil profile. You can sign up to attend here.

Robert Kremer discussed these interactions in our fascinating podcast interview:

John: In our experience working with many different farms, I would say, just off the top of my head, that greater than 90 percent of the farms we work with have experienced severe manganese deficiencies. I wonder about the long-term effects of this. When you have glyphosate accumulation, you have this shift in the fusarium population, and you have oxidizing organisms that are immobilizing manganese. What are the long-term implications of that manganese immobility in the soil profile? How long does it take before that manganese might be released and converted back into a form that the plants can actually utilize?

Robert: Yeah, that is a concern. I think there are several issues here. You have the effect of the shift in the balance of the microbial diversity. It’s shifted toward a lot of manganese oxidizers, causing manganese not to be available. I think that over time, if one were to alter the management to include, let’s say, cover crops—or at least different crops within the rotation—this could stimulate other types of microorganisms that will help free that manganese, or that will at least compete with those oxidizers to reduce their impact. So that would be one possibility. And how long that will take, it’s hard to say. It may take a couple of seasons, or maybe less. That’s something that really needs to be looked into. 

The other issue is something we mentioned previously: how much manganese can be immobilized or chelated by the residual glyphosate and the residual AMPA? That, I think, is a very serious issue—especially in soils where the texture is such, or the level of phosphorus is so low, that you don’t have any competition with the glyphosate or AMPA. They will obviously chelate or immobilize manganese as well. I don’t think we have any real good information on how long that can happen or what the extent of that situation is as far as tying up manganese over the long term. Taking all that together—the shift in the microbes, the residual glyphosate and AMPA, and the basically continuous corn-soybean rotation—if that continues, the manganese problem may persist.

John: When you speak of bringing crops into a rotation to help reduce some of that manganese and to increase its availability, what are some crops that are really effective at having a reducing effect and shifting the biology and the availability of manganese in the soil profile?

Robert: I don’t have any specific ones in mind, but certainly when you have a diversity of cover crops in a mix, there will be some that will support different microbial communities that are able to mobilize these micronutrients, and others that can actually mobilize the nutrients themselves. A common example is the use of buckwheat, or some of the brassica crops, which can mobilize phosphorus or neutralize nitrates. 

And then let’s say you add something like sorghum to the rotation—grain sorghum or sweet sorghum. From my experience, sorghum has a keen ability to host a lot of mycorrhizal fungi in its root system. And mycorrhizae are very adept at mobilizing many nutrients—not just phosphorus. If you could add a crop like that, or other crops that can host mycorrhizae, that would be a very good way to get around the manganese problem, to improve regrowth, and to improve the overall diversity of the microbial community.

Low level manganese deficiency in peaches:

2020-06-11T06:52:31-05:00June 11th, 2020|Tags: , , , |

Cell division for fruit size and quality

Potential fruit or grain size is determined during the cell division period immediately after pollination. The cell division process can continue for as little as 5 days, to as long as 40 days, but most crops have a 10-14 day cell division window. During this window, the cells in the embryo are rapidly dividing, 2-4-8-16-32-64 and so on. At the end of this 10-14 day window, cell division stops completely, and the remainder of the fruit fill or grain fill period is focused on cell expansion, filling each cell with proteins, sugars, and water.

Fruit that are tightly packed with more smaller size cells are firmer, store better, are crisp, and crunchy. Fruit with more cells can be much larger in size when all the cells are filled with water and nutrients. Fruit with more cells are resistant to cracking and splitting. In general, almost all the fruit quality characteristics we seek can be improved by increasing the number of cells formed during the cell division period, with the exception of some fruit where excessive size is a negative.

The nutritional factor which limits the number of cells formed during the cell division period is calcium, because calcium is needed to form the cell membranes for all the rapidly dividing cells in the fruit embryo.

An easy step to produce exceptional quality and yield is to ensure a peak of available calcium during the cell division period.

This means any soil applications of calcium need to be timed so the peak of the release curve coincides with the crops peak demand curve during cell division. Applying gypsum or limestone on tree fruit in the spring is much less effective than a fall application, because it doesn’t release quickly enough to be available during cell division right after pollination.

In almost all cases, when fruit express physiological symptoms of inadequate calcium, which we call blossom end rot, bitter pit, or cork, it is because there is inadequate calcium supply during the cell division period.

Quite often, this inadequate calcium level in the plant or in the embryo may not be the result of low calcium in the soil. Poor calcium absorption can be the result of excessive potassium, low boron, or low manganese availability in the soil. Any of these conditions will limit calcium absorption, and thus negatively impact fruit quality.

I have been framing the discussion around fruit, but these concepts hold equally true for grain crops.

These grapes are still 3-4 weeks from harvest, and each berry is about 60% of mature size. When was the last time you bought grapes like these? Would you like to grow crops at an equivalent level of health and quality? If so, managing calcium and the associated nutrient interactions during the cell division stage becomes a top priority.

The first thing you will cut is all potassium applications until after the cell division stage is completed. To achieve this, you likely needless fertilizer application, not more. And most likely also timed very differently.

2020-06-09T20:19:17-05:00June 10th, 2020|Tags: , , , , , |

Oats, a very effective disease suppressive cover crop

Many have observed the plant performance improvements of crops being grown after oats. It is fairly common to observe not only an increase in disease resistance, but also a yield increase because of the increased manganese availability, which increases a plants (and animals) reproductive performance.

But there is another very important point hidden in this dialogue. Before crown rust was a significant challenge, oats did not have a reducing/disease suppressive effect. The plant secondary metabolite profile of oats changed once they were bred to be resistant to crown rust. This change in the metabolite profile resulted in a changed profile of root exudates, which converted a plant with a former oxidizing effect on the soil redox environment – a disease enhancer, to a reducing effect, or disease suppressive.

This means we need to consider the possibility that some plants which currently have an oxidizing effect, such as modern wheat, can be shifted to having a reducing/disease suppressive effect when we change the plant metabolite profile. We know we can change the plant metabolite profile significanly based on how we manage plant nutrition. Breeding is not the only pathway, and certainly a slower pathway, to developing crops which produce a disease suppressive microbiome.

From our interview:

John: You spoke briefly about the use of crop rotations and that 85 percent of the effect, 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?

Don: Again, that’s going to depend on your disease and your overall soil biology. For instance, if you’re dealing with take-all, Gaeumannomyces graminis—the root and crown rot of cereal crops—you’ll find that brassica species have a suppressive effect. Perhaps the best cover crop overall is oats—another cereal crop. When we bred crown-rust resistance into oats, this also gave us an oat crop that provided disease control—take-all control—for our wheat and barley.

The reason is that crown-rust-resistant oats also produce a glycolcyanide root exudate that suppresses the manganese-oxidizing organisms. If you suppress the manganese-oxidizing organisms, you also suppress 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.

The shikimate pathway is a pathway that gives tolerance or resistance to take-all, because that’s where the lignotubers are formed. Lignification and callousing—all of those materials are produced through the shikimate pathway. And manganese is a very critical component in that pathway—at six or seven different steps in the pathway. If you inhibit the availability of manganese—if you have a good, strong mineral chelator that ties up manganese—you’re going to increase take-all, because you reduce the functional availability of manganese for the plant in its own defenses.

A plant like rye is very efficient in the uptake of manganese and other micronutrients. Rye takes care of itself with its resistance to take-all pathogen, but it doesn’t do anything for a subsequent crop. It 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 wheat-rye cross, if it doesn’t contain that section of the rye chromosome that is responsible for micronutrient uptake, then the triticale will be as susceptible to take-all as a wheat crop.

You don’t get a crop-rotation benefit out of rye like you do from oats. The root exudate of oats has a very strong antimicrobial compound against the manganese-oxidizing organisms that make manganese less available. You’ll see that effect—that change in the soil biology—carry on for two or three wheat crops after an oat crop. Subsequent crops will have very little take-all. Oats probably has the most dynamic effect in this regard.

Brassica species—canola or mustard—also produce quinolones and some other materials that have a similar ability to reduce take-all as the glycoprotein in oats. Following canola, you’ll see an increase in some of the other diseases. It’s not just influencing one particular disease. If you’re using Roundup-ready canola, genetically engineered canola—where you’re adding a very strong mineral chelator, because that’s how glyphosate works, by tying up those minerals in the physiology of the plant—if you’re growing Roundup-ready canola and applying glyphosate, it’s going to move 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 head scab and the toxins of that particular plant pathogen. So, you’re changing the dynamics of the system with the particular management tools that you use. 

Condensed harvest window on blueberries

When plants have a surplus of energy, reproductive buds are all large and uniform in size, blossoms all pollinate at the same time, and fruit all mature in a condensed window. For machine-harvested blueberries, this can mean harvesting 90% of the crop in a single pass. For fresh-market, hand-picked berries, this can mean harvesting the entire crop in 4-6 passes over as many weeks. You can calculate the increased labor efficiency and reduced harvest costs.

2020-06-01T20:34:21-05:00June 2nd, 2020|Tags: , |

Discontinuing all pesticide applications at once

The most intriguing element of the interview with Michael McNeill was the suggestion that you should stop all pesticide applications all at one shot. I know it can be done because this was the approach we took on our farm years ago, but I have been hesitant to recommend that leap to others.

Our approach in our consulting work has been that we have to earn the right to discontinue pesticide applications by producing such a healthy crop, it becomes resistant to possible pests, and you no longer need the pesticides. Of course, achieving that outcome is made much more difficult from the continued pesticide applications.

We also have slightly different contexts. We are working with many high-value crops, with more intense pesticide applications, where we don’t have the luxury of making any mistakes. Of course, broadacre producers would say they don’t have the luxury of making any mistakes either.

In practical application in the field, I am comfortable making recommendations to discontinue the use of fungicides and insecticides when we have sap analysis reports, and we can observe the nutritional profile of the crop is not conducive to infection.

In any case, who can argue with success?

From the Regenerative Agriculture Podcast with Michael McNeill:

John: Michael, what is the one action that you would advise all growers to take right now that could make the biggest difference in their operations?

Michael: Stop poisoning the soil.

John: I guess that’s easy!

Michael: It’s real simple—just stop.

John: That sounds simple. It sounds easy to do—but how? How do you manage that?

Michael: It is a challenge, if you’ve spent most of your life doing things one way. Stopping doing something is not necessarily easy. But that’s the one action growers need to take to be successful.

John: Are there transition steps that can be taken to move away from that? What are what are some of your growers who have moved away from using herbicides doing?

Michael: I have seen a full array of actions—from taking baby steps to jumping off the cliff—100 percent stop. And I have seen growers—from the smaller, 300- to 400-acre growers to the 10,000- to 15,000-acre growers—step off the cliff. And it’s worked really well for them. I was really concerned about some of the larger growers, but I found that they had the management ability and the resources to make it happen. And once they understood what they were doing and why they were doing it, they were very successful.

And I think that’s something that most people don’t believe. I get that thrown in my face almost every day. “I can’t do that—I have too big an operation.” And I really enjoy throwing it back—”Well I know somebody who has.” Those successful large growers have not necessarily added more hired men or anything. The one thing that they have added—if they’ve made a mistake or a failure—they’ve had to employ a large number of people for a short period of time to hand-weed a field. If they made a mistake, that’s the only fix there is.

John: I’m struggling with this a little bit myself as well. So, when you use the words “stepping off a cliff,” are you talking about eliminating 100 percent of all herbicide applications right out of the gate? What does that mean, exactly?

Michael: All pesticide applications.

John: Aren’t you going to lose your crop to potential disease and insect pests when you do that?

Michael: When you do that, you’d better have read that book that I just suggested (Mineral Nutrition and Plant Disease – Datnoff, Elmer, Huber )—so that you understand that you need to have the right micronutrient balance to keep that plant healthy enough to protect itself. And you can do that through starter fertilizers, foliar feedings—multiple foliar feedings—you can pull it off.

John: What are some of the failures of growers who have tried to do this, and what has been their degree of success?

Michael: By and large, I have had all successes. I’m trying to think of a failure, but I really can’t think of any. I make sure they really understand and know what they’re doing when they do it. I’ve had a few where they missed a field or two, timing-wise—a rain caught them and they didn’t get the weeds taken care of when they should have. But they were able to get it cleaned up—to the point where it did not suppress yield.

John: Wow. How do their yields compare?

Michael: I think that their yields have been going up. That’s what’s been somewhat shocking. I want to be sure it’s attributed to that—not just necessarily a good growing season. Because we’ve had some good growing seasons recently. But their yields have continued to climb quite rapidly. They’ve moved to a different yield plateau.

John: So you’re saying that their yields are actually higher now than they were when they were using herbicides and pesticides regularly?

Michael: Yes.

John: Well, that’s exciting, because those are the same types of things that we’ve observed in the fruit- and vegetable-production world. And those are really the types of regenerative systems that we seek to create and to establish, and I absolutely agree with you that those are possible.

From a management perspective, the one piece we often do a bit differently on fruit and vegetable crops we work on is that we don’t usually advise people to “step off the cliff,” to borrow your terminology. Rather, we advise growers to manage nutrition and to regenerate soil health to a higher plateau of performance—to the point where growers earn the right to eliminate pesticides. Then, all of a sudden, we don’t have problems with powdery mildew anymore. We don’t have problems with spider mites anymore. We don’t have problems with leafhoppers anymore. When we get to that much higher plateau, and we no longer have the problems, then we start cutting and eliminating pesticide applications.

It seems a bit scary to me—when you’re managing a crop that is really valuable—to suggest eliminating all pesticide applications immediately. But obviously, you’ve been successful in doing so.

Michael: Yes, it’s worked. And it was really scary when I first started doing that. But I’ve learned the few things that you have to be sure to accomplish: getting the soil as healthy as you can, and helping the plants be as healthy as you can. And that’s pretty hard to do when stepping off the cliff. But it can be done.

2020-06-08T11:49:26-05:00May 29th, 2020|Tags: , , , |

The effectiveness of microbial inoculants in fixing nitrogen

Soil biology can ‘fix’ and supply more nitrogen, and faster, than they are often given credit for.

The wheat field section on the right received an October application of AEA’s soil primer, which includes bacterial inoculants and stimulants. By March the following year, soil analysis reported an additional 80 units of N available for the crop.

To achieve these results, the soil must have adequate microbially active carbon, good gas exchange, and good moisture levels.

Soil microbial populations can regenerate quickly when given the right environment and support. Regenerating soil health can be accelerated to a few years, it is not a process that needs to take decades to achieve a significant turn around.

2020-05-28T07:05:35-05:00May 28th, 2020|Tags: , , , |

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.

What healthy peas actually look like

These are fresh market hand-picked peas grown with Advancing Eco Agriculture nutrition and biology management systems, after three months of treating compacted mostly dead soils.

We know that plants routinely are only photosynthesizing at 15%-20% of their inherent capacity. Increasing this performance level to 60+% is a realistic objective for field-scale agriculture. The steps to achieving these results include expanding leaf width, increasing leaf thickness, increasing chlorophyll concentrations, ensuring generous levels of manganese for water hydrolysis, and supplying adequate CO2, in addition to the obvious needs for water and sunlight.

How much more photosynthates would you expect these leaves to produce above the average in a 24-hour photoperiod?

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: , , |
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