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How to reduce herbicide application rates

The soil health challenges of glyphosate use are becoming well known. Don Huber has reported that even a single application of ten ounces per acre is enough to alter the microbial community in favor of oxidizing – disease enhancing organisms.

I am not aware that any other herbicide is known to have the strong antibiotic effect of glyphosate, though each has it’s own set of environmental and public health challenges.

Some growers have figured out how to eliminate herbicides altogether. Other growers are still on the pathway of figuring it out.

Robotic weed control technologies are being developed that may make herbicides obsolete in the future, but they are not here yet.

Given this state of affairs, it would seem wise to figure out how we can apply the smallest amount of active ingredient possible and maintain or improve effectiveness.

When we describe designing nutrition applications, we find that we get the greatest performance when we use synergistic stacks of products from different categories, for example: bacterial inoculant, fungal inoculant, microbial stimulant, microbial food source, plant nutrients, plant stimulants.

We can use this same concept to reduce the required rates of herbicides. Some growers have reported reducing rates by upwards of 80% and maintaining effectiveness using a combination of different strategies.

The practices which are known to improve herbicide performance include:

  • removing all minerals from the water, particularly carbonate and bicarbonate
  • acidifying the water
  • premixing the herbicide with a vegetable oil
  • adding sugar to the spray solution
  • adding fulvic acid to the spray solution
  • structuring the water

Each of these practices increases the effectiveness of any material added to a spray solution (including foliar sprays). When we stack practices together, the improvement in results can compound.

When we stack these practices together, they need to be added in the right sequence, much the same as products should be added to a spray tank in the correct sequence. Here is the sequence that I have observed to be the most successful:

  1. Demineralizing the water, most commonly using reverse osmosis (RO). RO is very inexpensive for the reduction in active ingredients it can produce. This step alone can account for a reduction of 30-40% in product required.
  2. Structuring the water after it has been through an RO device and demineralized.
  3. Premixing the herbicide with vegetable oil 50/50 on a volume basis, and then add to the tank. The theory is that coating the compounds with vegetable oil will improve their absorption by the crop. I have some question marks about how this might work, and how much it actually does, but growers are reporting observable improvements.
  4. Add any acidifying agents to tank, such as ammonium sulfate. This may require much less than you expect when you use RO water to reach a low pH.
  5. Add fulvic acid to improve leaf absorption.
  6. Add sugar to contribute stickiness, and improve leaf absorption.

Exercise caution when using this approach with selective herbicides. The applied products will be much more effective, and can easily damage the non-target species. Test how much application rates need to be reduced, they will almost certainly need to be reduced to avoid burn.

I have observed complete weed control with 8 ounces of RoundUp per acre, roughly 4 ounces of active ingredient glyphosate per acre.

What practices have you used to reduce application rates while improving effectiveness?

2021-02-08T11:08:40-05:00February 10th, 2021|Tags: , |

Soil glyphosate limiting manganese availability

We have observed many soils that do not deliver manganese well in spite of having large manganese reserves in the soil profile. In most cases, this is a result of manganese oxidation. Manganese oxidation can result from chemistry interactions, but a great deal of manganese oxidation occurs as a result of fusarium overgrowth from accumulated glyphosate applications.

Here are some thoughts Robert Kremer shared in our conversation on our podcast interview:

John: Coming back to the conversation about glyphosate and AMPA, how does glyphosate—and the accumulation of glyphosate and AMPA over extended periods—impact overall soil health?

Robert: We know that there are some indirect effects of continuous use of glyphosate on soil health, because we usually measure a lot of the biological parameters when we set up soil assessments. We see that there are some effects on some of the beneficial bacteria that are involved in plant growth promotion, such as producing plant growth regulators that stimulate root growth and other beneficial bacteria that will produce pathogen-suppressive compounds. We’re noticing that glyphosate tends to suppress those beneficial groups of bacteria, so that has an effect on subsequent plant growth as well. So we feel that there’s a problem there.

I briefly mentioned the effect on some of these microorganisms that are known to cause certain micronutrients to be immobilized, and therefore not available for plant uptake. One of these is manganese. And manganese, of course, is very important for the activity of many enzymes that are involved in many of our metabolic pathways. If it’s tied up, you may have poor photosynthesis. You may have poor amino acid formation because you don’t have enough of it to satisfy the needs of the enzyme.

We’ve found, for example, that fusarium that will colonize the roots of plants that are treated with glyphosate. Fusarium is a manganese oxidizer, so it will immobilize manganese. If it’s on the root system, manganese is not going to be taken up. And if it’s built up in the soil—whether there’s a genetically modified crop there or not—it’s going to remain in the soil. It’s going to continue to immobilize manganese. If you don’t have a lot of available manganese, that’s going to affect the overall soil health as well.

There are a lot of other things. Glyphosate may exchange with phosphorus in the soil, and then you have problems with either excess phosphorus, or, if phosphorus isn’t being taken up by the plants, it can become an environmental problem. We discussed the quality of the organic matter, because we basically just use two crops as the source of the organic residues being returned to the soil. If we don’t have the microbes there to decompose them, or if there’s not a diverse enough quantity of organic substances to help build up soil organic matter, then that will affect soil health as well, because—like I mentioned before—organic matter is one of the key indicators for good soil health.

2020-07-20T22:09:29-05:00July 21st, 2020|Tags: , , , |

Embracing the connection between agriculture and public health

My first introduction to the concepts and ideas behind regenerative agriculture was from a three day course with Arden Andersen fifteen years ago. Arden spent the first entire day describing the modes of action of various pesticides and how they influence our bodies and hormonal system. We were the pesticide distributors for the local region at the time and the information was eye opening for us. Over the next several years, I studied the modes of action of pesticides, and learned as much as I could about their impact on ecosystems, animals, and people. 

It can be challenging to have a conversation about the impact these compounds are actually having, particularly when we feel we are still dependent on them in some way. It can be hard to hear about the negative impacts they have, and the long term consequences. 

I believe it is much more powerful and useful to be for something than to be against something.  I do not believe that GM crops and pesticides are needed to develop regenerative agriculture ecosystems with much higher production and quality than is mainstream today. I don’t believe it useful to be constantly describing the negative impacts they can have, but to instead focus on the opportunities and untapped potential other practices and products can bring. 

With that being said, I believe it is valuable for us to understand the modes of action of different pesticides, and their individual and collective impact on public health. Farmers can have a tremendous positive impact on public health, because we can grow healthy food that boosts people’s immunity and prevents them from becoming ill. On the other hand, we can also choose to grow food that is laced with toxins with a long list of known and unknown negative impacts. 

In conversations with podcast guests over the last several years, we have made passing comments about some of the known impacts of pesticides and glyphosate on soil and plant health, but have never really discussed the impacts on human health. In this episode with Zach Bush, I chose to talk about the human health impacts of pesticides and glyphosate in particular, since it has become so controversial in recent years. 

This discussion is not a condemnation of those who feel the need to use these toxins, but an effort to bring more clarity and light to the discussion. It is valuable for us to understand, and once we understand, to make responsible decisions when we know the health implications. 

I tremendously enjoyed this discussion because of the heart and empathy Zach brings to any conversation, and I am sure you will to. Please let me know what you think. 

You can listen to the episode and read the show notes here.   

2020-06-16T08:00:42-05:00June 16th, 2020|Tags: , |

Developing disease suppressive soil

Diseases and insects only become a problem when plants are unhealthy, lacking nutritional integrity and microbiome integrity. The tools of nutrition management and microbiome management are so effective, they have been and are used as management protocols for bio warfare weapons mitigation.

From the Regenerative Agriculture Podcast with Michael McNeill:

John: Michael, we’ve been circling around this topic of soil health and the impacts of tillage, herbicides, animal manures, cover crops, and so forth. At the beginning, you mentioned that there’s a correlation between soil health and the diseases that are present. You mentioned some work you were doing in Maryland—studying diseases as a weapon. What did you learn from that experience? And how does all of that tie into what we’re talking about?

Michael: Let’s say you want to use a fungal disease as a weapon—that you can get this disease introduced into the soil. Not only does it kill a crop this year—it’ll continue to kill it into future years. So hey, that’s a pretty good weapon—you shut down a people’s food supply. They have a problem.

Well, if you have good pseudomonas bacteria in the soil, they act as a policeman in the soil, if you will, and they’ll take out the pathogenic fungi that can arise. But if you use products like glyphosate—that’s an antibiotic type of product—you’re going to kill all the pseudomonas, and then you have no protection. And it’s very easy to get a huge population of fusarium going in the soil, which probably is a pathogenic fusarium—or pythium or phytophthora. You’ve lost the natural balance. If you have that balance, though, the pathogenic fungi are not going to do much to you. Your good bacteria will clean it right up.

John: So you can actually have a disease-suppressive soil where you don’t have challenges with those pathogenic fungi. I think I also heard you mention that you were working on developing solutions to those diseases as weapons. What were the types of solutions that you were working on?

Michael: There are all kinds of approaches. If you need a fast cure, of course you’ve got to look at chemistry and the fungicides and that sort of thing. But what you find is that if you get the soil contaminated, how do you fix it? Because if you put anything on it, you’re going to kill everything in the soil. Using a soil sterilizer is not necessarily a great idea. But there is microbial life in the soil that will hold everything in balance. And if you have the right nutrition available, everything will take care of itself.

I’ll use you as an analogy, John. If your nutrition gets pretty poor, you’re going to get pretty run down, and you’re going to be very susceptible to all kinds of diseases. Would you agree?

John: Oh, I think that’s just the story of the people who are trying to sell me supplements. (Sarcasm, I take many supplements, and believe they are important.)

Michael: That’s funny—but when that occurs, you can take this supplement or this drug to prevent the disease, but you’re still improperly nourished. You’re going to get another disease, and then you’re going to get another disease. But if you get your nutrition back and properly balanced, and everything is at the correct level, your immune system starts to function properly. A good share of your immune system is in your digestive tract—there are a lot of microbes working for you.

And the soil is no different. You get those microbes working for you, you’re going to stay healthy. The soil is going to stay healthy, and so are the plants.

John: Are you saying that when you manage the nutritional balance of the soil and the microbial population of the soil, that it’s possible to grow crops that don’t have disease?

Michael: Yes. When a plant is perfectly healthy, it’s very hard to get a disease to invade it, and an insect will not even stop to look at it. Why is that? It’s because an unhealthy plant cannot convert the sugars it’s produced into complex sugars—starches and lignin—which insects and diseases can’t use. They can use simple sugars and the nitrate nitrogen in the plant. The nitrate nitrogen is taken up by the plant, and it’s immediately converted into amino acids and proteins in a healthy plant. An unhealthy plant—a plant that does not have the right mineral balance to make all those processes and cycles work—will have a pretty heavy load of nitrate in it—a fantastic food for the insect. They can detect that, and they will land on that plant and feed on it. Disease and insects are Mother Nature’s garbage collectors—getting rid of the bad stuff, the weak plants.

Impacts of glyphosate residue on seed germination

Some new research1 describes the impact of pre-emerge glyphosate applications on seedling development and yields, and the impact of prior year appplications. The conclusion: you certainly want to avoid any application until well after seedling emergence, and prior year applications are probably impacting your current yields. It seems we need to begin using alternatives immediately.

The article itself is a great read, here are a few excerpted highlights:

  • The seed germination of faba bean, oat and turnip rape, and sprouting of potato tubers was delayed in the greenhouse experiments in soils treated with GBH (glyphosate based herbicide) or with pure glyphosate.
  • The total shoot biomass of faba bean was 28%, oat 29% and turnip rape 58% higher in control compared to GBH soils four weeks after sowing.
  • Grazing by barnacle geese was three times higher in oats growing in the GBH soils compared to control oats in the field. 
  • Our results indicate that the use of GBH, as well as surfactants and other ingredients of commercial herbicide products, have different effects on the seedling establishment of seed- and vegetative-propagated crops.
  • In all the studied seed-propagated crops, germination was faster, and in turnip rape and oats the total germination percentage was higher in the C soils compared to the pure G- or GBH (Roundup)-treated soils.
  • seed-propagated crops with limited endosperms as an energy source are likely to be exposed to GBH residues in soils following water imbibition at the beginning of the seed germination.
  • Our results suggest that the use of GPH may have unintended and undesirable consequences for farmers. The speed of germination and early growth may be crucial for the plants, depending on the abiotic and biotic environmental factors. Especially in spring, earlier individuals may benefit from moisture and a lack of competition. Thus, delayed germination and weakened growth of seed-propagated crops in GBH-contaminated soils may invalidate the intended crop protection if targeted weeds get a head start in early spring.
  • The use of GBH may increase the yield loss caused by flea beetles and further challenge spring-planted oilseed rape and turnip rape cultivation
  • Glyphosate can enhance the attractiveness of plants to vertebrate herbivores. In the field experiment, the oat plants growing in GBH-treated experimental plots experienced heavy barnacle geese grazing while the adjacent plants in C plots were only mildly grazed. 
  • Glyphosate is known to inhibit the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) in the shikimate acid pathway, thereby interfering with the production of tryptophan, phenylalanine or tyrosine, which are precursors of proteins and other molecules, including growth promoters (e.g., indoleacetic acid, IAA) or secondary compounds with known importance for plant defense against herbivores (e.g., tannins, anthocyanins, flavonoids, and lignin.
  • Overall, the effect of pure glyphosate was weaker compared to that of the commercial formulation (Roundup Gold) containing the same amount of glyphosate. This supports other studies suggesting that other ingredients in GBH, such as surfactants, solvents, and preservatives, could also cause adverse effects on non-target organisms.
  • Our results clearly demonstrate that the use of GBH has detectable effects on crop plant germination and growth, and their quality to herbivores, even though we used field-realistic concentrations of GBH and the experimental plants were introduced into the soil after a two-week withholding period.
  • In contrast to seed-propagated crops, GBH treatment boosted the growth of vegetatively propagated potatoes, and glyphosate appeared to accumulate in the potato tubers. This leads to the critical question of whether the residues in potatoes have consequences for the subsequent year’s yield.
  • These results emphasize the importance of a more comprehensive understanding of the effects of GBH on the productivity of crop plants and their chemical ecology, affecting their pest and pathogen resistance and thus the need for crop protection.
  1. Helander, M., Pauna, A., Saikkonen, K. & Saloniemi, I. Glyphosate residues in soil affect crop plant germination and growth. Sci. Rep. 9, 19653 (2019).

 

2020-03-16T13:54:09-05:00January 14th, 2020|Tags: , , , , |

Terminating cover crops with glyphosate

For those who are yet undecided,

Evidence continues to accumulate regarding the pronounced negative effect of glyphosate on soil health, and how it leads to disease enhancing soils.

A new paper recently published describes how using glyphosate to terminate an oats cover crop alters the soil microbial profile as compared to a cover crop that is mowed1.

The conclusion? Glyphosate alters the microbial community dynamics, some species become more dominant, while others are suppressed. Not a surprise. We know from prior work by Huber et. al. that glyphosate applications shift the microbial population in the direction of a disease enhancing environment.

A second recent publication describes how minerals are lost from cover crops sprayed with glyphosate and don’t seem to remain plant available in the soil profile.2

If you want to develop disease suppressive soil that prevents possible infections of soil-borne bacteria or fungi, there doesn’t seem to be a place for glyphosate in the toolbox.

1. Allegrini, M., Gomez, E. D. V., Smalla, K. & Zabaloy, M. C. Suppression treatment differentially influences the microbial community and the occurrence of broad host range plasmids in the rhizosphere of the model cover crop Avena sativa L. PLoS One 14, e0223600 (2019)..

2. da Costa, J. V. T. et al. DECOMPOSITION AND NUTRIENT RELEASE FROM CROTALARIA SPECTABILIS WITH GLYPHOSATE APPLICATION.

2020-03-16T13:49:21-05:00January 3rd, 2020|Tags: , , , |
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