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Why product performance varies according to plant health

Sometimes products are applied to a crop at a fraction of the label rate and produce a large crop response.

In other instances, products may be applied at rates several times higher than label rates, but only produce a minimal response.

It is a common observation that products perform differently on farms in the same neighborhood.

Depending on the product we are evaluating, there can be a number of contributing factors that produce these different outcomes. The macro factors include:

  • soil physical structure,
  • soil mineral balance,
  • soil microbial populations,
  • plant health,
  • tank mix formulation
  • plant species present and stage of development,
  • climate conditions

Of these seven macro factors, the impact of pre-existing plant health on product performance is often not considered. We have observed significantly different product performance results at different stages of plant health. The healthier plants become, the fewer inputs are required, and the greater crop response is produced by those inputs.

I put together a 10-minute audio clip and diagram on Kind Harvest to describe what we are observing. You can find it here.

 

2020-11-10T08:15:31-05:00November 10th, 2020|Tags: |

Launching KindHarvest, the agriculture social network

Every person knows something I don’t know. Every grower has observed or experienced something I would like to learn. The ability to exchange ideas and information is very important in agriculture. We need to share our knowledge with others online as well as in person. You would think in 2020 this would be easy, but it seems to have gotten more difficult.

Mainstream social media platforms are noisy. They are often an echo chamber that does not provide thoughtful answers. They are designed to be addictive and keep us hooked, because our attention is the product they are selling. The exchange has degraded to the point where it can’t be called a conversation anymore.

There is widespread discontent from folks who are tired of censorship and the invasion of our privacy for the purpose of feeding us ads.

We need better. So we are building it.

KindHarvest is the agriculture social network. Our intent is to bring together like-minded people and provide a space for networking, thoughtful conversations, and exchange of ideas.

You can find valuable answers and connect with colleagues from around the world better than you have been able to on other platforms.

On KindHarvest we bring together the best features you are familiar with. You can exchange instant messages with a circle of friends. You can tag people in posts and updates. You can contribute to discussion forums. You can create and join groups. You can find others with shared interests and connect. You can participate in and create in-depth courses. You can write in-depth articles that everyone can see. You can create an archive of documents and files you want to share and reference.

We respect your privacy. On KindHarvest you are the customer, not the product. Our terms of engagement are easy: Be Kind.

Click here to join in, share your insights, ask questions, and invite your friends that you would like to see here as well. Thanks for showing up, and making a positive difference in the world!

Welcome to KindHarvest!

2020-11-09T06:38:59-05:00November 9th, 2020|

Thinking deeper on the disease triangle

Elementary discussions of plant pathology describe the disease triangle almost without fail.

It has become a standard inclusion in many presentations, and a quick image search will find hundreds of graphical designs that have been developed to describe the idea.

The foundational idea appears quite simple at first glance. For a ‘dise-ease’ to express itself requires a combination of three elements:

  1. a susceptible host,
  2. a potentially pathogenic organism,
  3. the proper environment,

This seems like an obvious and simple explanation. We accept it without much question and move on to the next part of the discussion, which usually revolves around controlling ‘pathogens’ when the combination of these three elements is met.

Rather than moving immediately to the control conversation, and assuming an infection has occurred that we have no influence over, we might dig a bit more deeply into each of the three elements. When we understand these three elements fully, they will give us all the information we need to prevent any ‘dis-ease’ from expressing in the first place. Prevention is often easier and more effective than a cure.

When we consider the definition of a ‘susceptible host’, what are the parameters that define a susceptibility? What are the differences between susceptible and resistant cultivars? Does the organism require a certain amino acid and carbohydrate profile that some cultivars do not provide? What are the resistance mechanisms that are present in some cultivars, and in some growing conditions, but not in others?

What defines a ‘potential pathogen’? We know from the research being conducted on the microbiome, as well as the work described by James White and Don Huber in our podcast discussions, there is no correlation between the presence of a potential pathogen and an actual infection. Soil organisms that might become pathogenic (such as fusarium and verticillium) actually develop symbiotic relationships with plants when the plant has a healthy, disease suppressive microbiome. For an organism to infect a plant and produce disease requires compromised soil biology, and a compromised microbiome.

What defines a ‘proper environment’? Our first thoughts generally go to the external climate, humidity and temperature. What about the plants internal environment, and the soil environment? From Olivier Husson’s breakthough work on the biophysical environment required by different organisms, we know that each organism requires the plant and soil to be in a specific redox state. The plant pH and redox, and soil pH, redox, and paramagnetism each need to be within a defined zone before an organism can infect a plant and produce disease.

The solution to effective disease prevention is actually very straightforward. We need to understand exactly what defines a susceptible host, a disease conducive microbiome, and the internal plant ‘environment’ for each pathogen. When we understand these elements, it becomes very easy to manage the crop in a way that prevents these organisms from producing disease, even when the organism is abundantly present, and the climatic environment is considered ideal for disease expression.

For which ‘disease’ organisms would you like to understand the elements of the disease triangle more deeply?

2020-11-03T16:18:21-05:00November 4th, 2020|Tags: , |

Managing airborne diseases with nutrition

It is possible for plants to become completely resistant to disease when we manage nutrition well. On the surface, this sounds like a bold statement. When you dig deeper to understand the enzyme interactions and infection pathways of different infectious organisms, it becomes clear how nutritional imbalance is a foundational cause that allows these organisms to express themselves and produce active infections.

In this discussion, I ask Don Huber how to develop disease resistance to airborne pathogens. To dig deeper into this subject, the best reference book available is Mineral Nutrition and Plant Disease. It is a very inexpensive book for the money it can save growers.

John: You and I have spoken before about the capacity of nutritionally sound plants to become resistant to soilborne pathogens and organisms residing in the soil. We haven’t spoken about airborne pathogens, such as bacterial and fungal pathogens. How can we develop plants that are resistant to those organisms?

Don: You’ll see the same thing there. Pathogens are looking at the plant and they’re attracted to it as a food source―a nutrient source.

Also, some of them actually require specific nutrients in order to cause disease. Several of the rusts, for instance, require an exogenous source of zinc on the leaf―an available source of zinc―before the spores will germinate and produce an infection. If you don’t have exudation of those minerals on the leaf, those pathogens are much less severe because they don’t have that specific nutrient resource.

Now, some of the pathogens can change that nutrient availability. A lot of bacterial pathogens―black rot and some of those organisms that produce siderophores, which are essentially chelators to increase the solubility and availability of iron—you’ll see that those siderophores are able to actually cause a depletion or a deficiency of available iron in the infection site for plant functions―for energy relationships―that iron is involved in.

It’s important to maintain the availability for the plants, in spite of the siderophore production by the pathogen. If we can block that siderophore production, we block the disease-causing mechanism for that particular pathogen―that particular organism―whether it’s black rot or rust.

John: How do you block the siderophore production?

Don: We do that with some of the antibiotics that we use for bacterial disease control―whether it’s in humans or animals or plants. A lot of those are blocking siderophore production by the pathogen. You see that with fire blight on apples and pears and with black rot pathogens―Erwinia and Pseudomonas and Xanthomonas―that produce those siderophores.

We also block them nutritionally by compensating for the plant and keeping the plant’s metabolism and defense reactions fully active, so that in spite of what the pathogen is doing, we keep enough active and available nutrients for the plant that this doesn’t have an effect. The pathogen’s reduction is compensated for so that it can’t compromise the resistance of the plant.

John: It’s my understanding that many bacterial and fungal pathogens require a specific amino acid, or perhaps a general amino acid and carbohydrate profile, to be within the plant. When we change the amino acid profile, it’s possible to change susceptibility or resistance to some of these organisms, and that is one of the mechanisms by which different varieties are resistant or susceptible. Is that a correct understanding? Can you explain that a little bit?

Don: Yes, in part. The early fungicides that we used for apple scab, for instance, didn’t have any direct effect on the fungus. Their effect was changing the amino acid profile in the plant so that asparagine was no longer available or released onto the leaf surface. So the pathogen never had the essential amino acid it required for establishment and infection.

We see that with a number of amino acids. Certain amino acids will increase disease severity. Others will be a very strong inhibition of it. One of the techniques that I developed early on in my career was aminopeptidase profiling, where we could actually identify microorganisms just by their amino acid profile. When we had very difficult organisms to culture, all we had to do was run the aminopeptidase profile on that particular organism. Just with adding three or four amino acids to a little bit of sugar and minerals, all of those organisms that we had considered obligate, or very fastidious organisms, could be grown in a simple, well-defined culture media.

I’ve done that for the rusts and the mildew pathogens, as well as for many of the human pathogens. Wilford Lee has five patents for human pathogens―just patenting the media for their culture in the laboratory. I don’t know of any organism we have followed that system on, that we haven’t been able to culture in the laboratory so that we can do other studies. It was one of the grant proposals that Bruce Hemming and I had submitted to the Florida Citrus Foundation so that we could start getting information on control of HLB―greening disease on citrus. They could never get funding to do that.

Specific amino acids can be very inhibitory. That’s one of the things for the rusts and the mildews. Most people who have been trying to develop media for those obligate organisms want to make sure they don’t leave something out. The problem is that they throw everything in the mix except the kitchen sink, and one or two amino acids work every bit as effectively for some of those obligate pathogens in stopping their growth as any of our fungicides. That’s a very sensitive relationship.

It’s not a matter of making sure you have everything there―it’s making sure that some of those natural products and metabolites aren’t present to support the virulence mechanism of the pathogen. We see that with Fusarium and with a lot of the other pathogens―that nitrogen metabolism is very critical for them. One of the reasons you see shading controlling greening disease is that with shading you block photorespiration that provides those nitrogen intermediates for the pathogen.

2020-10-02T06:08:39-05:00October 2nd, 2020|Tags: , , , |

Managing shoot growth, terminal buds, and biennial bearing

For many perennial fruit crops, we can use shoot growth as an indicator of overall plant energy and vigor. It is common for shoot growth to slow down, and sometimes even stop completely, setting a terminal bud, during the fruit fill period.

When this occurs, it is an indicator that the plant is not producing enough photosynthetic energy to both fill fruit and develop growth, so it will sacrifice the new growth to be able to reproduce.

When we manage plant nutrition to optimize photosynthesis, it is possible to restart healthy new shoot growth, without the addition of nitrogen.

On these apple trees in Michigan, the trees set terminal buds on new growth tips in late June, during early fruit fill. We started working with this block this year and recommended foliar nutrient applications designed to increase photosynthesis to increase sugar production for the heavy fruit load.

Incredibly, the shoots that had set ‘terminal’ buds began regrowing! Perhaps terminal buds aren’t so terminal after all when supported with enough energy and the needed nutrition. These shoots continued to have healthy growth with tightly spaced nodes through the fruit fill period.

When trees have continuous healthy shoot growth with tightly spaced nodes, it is indicator they have enough energy to also set fruit buds for the following year, and we can effectively prevent biennial bearing.

2020-10-01T06:02:58-05:00October 1st, 2020|Tags: , , |

Improving liquid manure

We are recognizing that liquid manure often has a very negative effect on soil biology and soil health. It may deliver nutrients, but it comes with a long list of possible negatives.

It is often in an anoxic state (deeply anaerobic), where the organic residues contained within it are putrified rather than fermented. (which is the source of odor and microbial toxins)

The microbial activity which might be present in the liquid manure has often been suppressed or even shut down completely as a result of this anoxic state, along with the presence of antibiotics.

Liquid dairy manure generally contains quite a high salt content, which has a negative effect when applied to the soil.

In some cases, cleaners and antimicrobial chemicals from milking parlor waste wash-water are also put into the lagoon or pit. (Which is a very, very bad idea, and will increase weed pressure of velvetleaf and other weeds dramatically where this is applied to soil).

Often, when liquid manure is applied, dead earthworms can be found on the soil surface the next day. Might this be a signal that this product is harmful to soil biology?

The odor is also an indicator of fermentation and decomposition gone wrong.

It doesn’t need to be this way.

It is possible to turn liquid manure lagoons into fermentation tanks that turn this valuable nutrient source from something that is harmful to soil biology to a fermentation broth that is very beneficial to soil biology.

When healthy fermentation is taking place in a liquid manure pit there is no odor near the pit, and there is no odor when it is spread. It may still smell slightly like manure when spreading, but there is no ‘stink’ that spreads for hundreds of yards.

When healthy fermentation is taking place, there is no crust on top of the liquid manure, and there is no accumulation of sludge at the bottom. All the solids are consumed, fermented, and the entire lagoon turns into a nice consistent liquid.

Imagine turning all the liquid manure into a fermented product that resembles concentrated compost tea. This is what is possible, and it is a much more valuable nutrient source than anoxic liquid manure that suppresses biology.

A number of manure treatment products are on the market, with varying degrees of effectiveness. Old-time treatments that have been reported over the years include adding yeast, adding molasses, and adding hydrogen peroxide. These can still be effective sometime but seem to be less effective as more GM grains are used as feed, and more antibiotics are present. Here are three AEA products I have worked with for this purpose that I know work very effectively.

The first one is HumaCarb. HumaCarb is not as effective as the other two products in triggering healthy fermentation. It does improve fermentation, but not so actively that it drives the digestion of accumulated sludge. HumaCarb is unmatched in its ability to bind odor-causing compounds, and it does so fast. In one case, a neighboring farm was spreading liquid hog manure on an AEA customers farm, and the odor was drifting to the house a quarter-mile away. The AEA customer asked him to take some HumaCarb back and mix it in before continuing to spread. HumaCarb was added to the liquid pit at a rate of 1 gal/10,000 gallon of liquid manure, lightly mixed in, and then immediately resumed spreading. The very next load, (20 minutes later) the odor was eliminated completely. The following day there were no dead earthworms where the treated manure was applied, where the soil was covered in dead earthworms where the first load had been spread. Obviously, it was binding more toxic compounds than just the odors. Depending on the manure concentration, HumaCarb is commonly added at concentrations ranging from 1/5000 to 1/15,000.

The second product is Rejuvenate. Rejuvenate does not bind odors as rapidly as HumaCarb, and delivers the best results when it is added some time before spreading. Rejuvenate activates and amplifies the existing organisms in the liquid manure and speeds up fermentation. When Rejuvenate is added the crust is quickly dissolved, and some sludge is digested as well. When it is added in advance, as the manure lagoon is filling, it will prevent the development of odor simply by facilitating good fermentation. It is usually added at similar rates as HumaCarb.

When there is accumulated sludge a microbial inoculant called OP8 is the heavy hitter. OP8 can digest accumulated sludge that is feet deep, and it will do so quite rapidly. Usual recommended rates are 1-2 ounces per 100,000 gal, depending on sludge accumulation.

Rejuvenate and HumaCarb are not microbial inoculants, they only speed up the microbes that are already present. OP8 is an actual inoculant.

For the most rapid digestion and highest quality conversion from liquid manure to liquid gold, use a synergistic stack of all three.

Imagine liquid manure that truly smells good, is good for the soil, and has no chance of killing anyone from inhaled gasses? Imagine how much additional value you bring to your soil and crops when you add a product that drives soil health instead of reducing soil health?

2020-10-03T08:46:52-05:00September 28th, 2020|Tags: , , , |

Nutrition management for apple scab

Some apple varieties are quite susceptible to apple scab, while others are resistant.

Plant sap analysis indicates the resistant varieties are much better at absorbing cobalt than the susceptible varieties in the same soil conditions. They will often show 2-3x higher cobalt levels.

When we balance all the other nutrients and apply foliar applications of cobalt to susceptible varieties, apple scab is not present.  We have implemented this treatment successfully on enough different apple varieties on enough different orchard blocks to be confident of its success.

Many other diseases have similar correlations to nutritional imbalances and can be managed effectively by managing nutrition.

Preventing and reversing scab infections can occur very quickly. We expect to see reduced pressure within weeks of the first application. In several cases, we have been able to eliminate all the later scab treatments after cobalt was applied in the spring, within several weeks of beginning to work with a block for the first time. This reduced the pesticide budget requirements by $500.00-$600.00 in the first year.

Like any trace mineral, cobalt can easily be overdone. Don’t attempt treatments without using sap analysis to evaluate progress and nutritional balance.

Not all diseases respond this quickly to nutrition management, but many do. When we begin managing nutrition differently, we can dramatically reduce fungicide and insecticide applications on most crops.

These Gala apples had severe scab pressure in a mild scab year in the year before treatment. In the current year, they had no scab, in spite of heavy scab pressure.

2020-09-25T06:52:03-05:00September 25th, 2020|Tags: , , |

Unhealthy plants create unhealthy soils

The popular narrative is that healthy soils produce healthy plants. 

This is correct but incomplete.

We need to ask the question, what creates healthy soils? “Healthy plants”, is the right answer. 

Without the contribution of plants, soil is just decomposed rock particles; sand, silt, clay.

Plants contribute the carbon, the sugars, the energy that serves as a fuel source, and substrate to develop microbial populations that build organic matter and mineralize nutrients and make them available to plants. The humic substances and humus clay complex are the result of plant contributions to the ecosystem.

Healthy plants create healthy soil.

The key adjective in this statement is ‘healthy’. Unhealthy plants do not create healthy soil. In fact, the opposite. 

Unhealthy plants create unhealthy soil. 

In this post a few days ago, Robert Kremer described how the root exudates of GMO crops can increase the virulence of soil-borne pathogens. But wait, root exudates are supposed to be a good thing, no?

The influence of root exudates on soil microbial communities is determined by the complexity and quality of the compounds they transmit through the root system, not only the quantity of exudates. 

Unhealthy plants will transmit simple carbohydrates, non-reducing sugars, amino acids, and other compounds in ratios that enhance the virulence of pathogens, by providing them with a ready food source. 

Healthy plants at higher levels on the plant health pyramid transmit more complex carbohydrates, reducing sugars, polysaccharides, enzymes, and complete proteins, as well as plant secondary metabolites. 

Unhealthy plants may also transmit some of these compounds, but in different ratios from healthy plants. 

The different ratios of complex carbohydrates, enzymes and secondary metabolites produce a different microbial community response in the rhizosphere. 

Unhealthy plants that transmit a lot of simple sugars favor the development of a disease enhancing soil microbial community. They increase the virulence of disease pathogens present in the soil. 

Healthy plants that transmit more complex compounds favor the development of a disease suppressive soil microbial community. They decrease the virulence of disease pathogens in the soil, and actually convert them to have a symbiotic relationship with the plant instead of a pathogenic one. 

While healthy plants create healthy soils, unhealthy plants create unhealthy soil. This is why focusing on optimizing plant health in the current growing season provides such big soil health rewards. 

GMO crops generally have different carbohydrate and amino acid profiles from their non-GM counterparts, which produces a different soil microbial community. 

2020-09-25T11:44:39-05:00September 24th, 2020|Tags: , , |

Residue digestion and nutrient delivery

When fungal activity looks like this beneath the tree row, how long do you suppose leaf residue will be around to carry over disease to the next season?

How will this fungal activity compete with Armillaria and other potential pathogens in the rhizosphere? How will it influence nutrient availability?

From our observations and experience, soil biology can deliver essentially all of a plant’s macronutrient requirements without any added fertilizer, provided that the nutrients are already present in the soil’s native geological profile. When we farm the biology, we no longer need to import fertilizers that are generally already locked up in our soils.

It may not be wise to simply discontinue fertilizer applications if the soil biology is severely compromised. They need to deliver whatever does not come from imported fertilizers in order to maintain or increase yields and quality, and in challenged soils they are often unable to do so.

2020-09-22T16:43:18-05:00September 23rd, 2020|Tags: |

How GMO’s can influence soil microbiology

On several occasions, we have observed GMO corn crops and GMO corn stalk mulch produce a soil environment that enhanced disease, sometimes dramatically. Why would it be the case that GMO crops produce a disease enhancing soil environment, where non-GMO corn produces a disease suppressive environment?

Other research has identified that GM plants have altered carbohydrate and amino acid profiles in the root exudates, which seems to be a probable mechanism for producing an altered rhizosphere microbiome.

Robert Kremer and I approached this conversation in our podcast interview:

John: Earlier you mentioned the impact of genetically modified plants themselves, apart from glyphosate and AMPA. How do GMOs impact the soil’s microbial community?

Robert: Well, there’s not a lot of information. We found with soybean, for example, that genetic modification can have what are called pleiotropic effects—indirect effects due to the genetic modification that are in addition to the intended effect. In other words, effects that are in addition to the effect of making the plant resistant to glyphosate. And so there are things that can happen in the root system—with some of the early genetically modified soybean varieties, anyway—that even without being treated with glyphosate, the roots seemed to release a lot more carbohydrates or soluble carbon and amino acids. This is problematic because it attracts a lot of microbes that readily use this material, and many of those can be potential pathogens. So you have a potential problem not only with some root pathology, but it’s also possible to build up these segments of the microbial population and carry them over from year to year.

Another situation where we find these effects is in corn. Not in all varieties, but in many varieties that had been genetically modified to be resistant to insects using Bt, there was a side effect where some of the corn stocks would have a lot more lignin than others. Lignin is very difficult to decompose. That’s one of the reasons we sometimes see a lot of that residue being carried over for two or three years in the field—there’s so much lignin that it can’t decompose very fast.

And I think there are other situations that can occur. I had a Brazilian student here who looked at some of the nutrient composition. Some of the omega fatty acid ratios were changed in soybeans due to the genetic modification; that kind of thing. Now, I can’t say for sure if that has changed with some of the more recent cultivars, because I haven’t been looking at that very closely over the last few years. But, as you know, in our commodity agriculture, these varieties change almost from year to year. Some of the varieties that we were using fifteen years ago are not available anymore. So that’s always another problem. You just don’t know whether the effects of these newer varieties are any better or any worse unless somebody has a research program that’s addressing it.

John: Your first point is very intriguing. In essence, what you’re describing is that these crops and these plants may have the capacity to actually develop a disease-enhancing soil profile—which is interesting when you consider the long-term implications.

Robert: Right. That was a completely unexpected result that we had. And we were comparing it to some of the old non-GMO varieties like Williams 82 and Maverick, and they had much lower soluble carbon and amino acid release. So it was quite interesting, to say the least.

2020-09-21T20:35:48-05:00September 22nd, 2020|Tags: , , , |

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