Mycorrhizal Fungi: How They Feed Your Plants and Boost Soil Health

0:00 Okay, I'm growing some mycelium in my lab right now and I've been making pots out of it. So I grow mycelium on sawdust and then I dry it. And then once I bake it in the oven, it's hard as a rock and never takes on water again. I'm just interested in mycelium as a construction styrofoam replacement for styrofoam. I've just been messing around with it, super strong.

0:30 It'd basically be like chitin, just like crab shell, wouldn't it? It's hard as a rock once you dry it and it's light as a feather.

0:43 I'm gonna kick it off here, you guys, so we can. Okay, we'll pick this conversation up later. Yeah, that might be part of the questions. That's a very interesting concept there. Thank you guys for tuning in here, and as we let people get started, I just want to kick things off. Just letting you know everybody is muted here right now. We're gonna let our presenter speak for about 45 minutes and then we'll open it up to audience questions around 6:15. And so if you do have questions during the webinar, if you're watching on Facebook you can type them out there or in the Q&A portion or chat on Zoom. Really excited this evening to talk about biology, and with that we got an expert in that. He was showing me his door behind him right there has a mushroom on it, so clearly something that he's passionate about. And we made sure to find somebody that knows what they're talking about.

1:44 Dale, do you want to go ahead and introduce our speaker this evening?

1:48 Sure. I guess I could give you all a little of the history between us. I used to work for this guy in a roundabout way. He started the company Mycorrhizal Applications and selling mycorrhizal inoculants. I believe you were the first commercial mycorrhizal inoculant on the market. Maybe, maybe I am, but first one I was ever aware of. And I had a customer who had his fields inundated with the floods along the Missouri River and just had a completely dead soil, nothing was growing, no life whatsoever. So we were searching. He asked me, you know, what should I put back in here as far as microbes? I said, well, I'd start with mycorrhizal fungus. It's the most important microbe that you lose in this kind of situation. With a long discussion, he said, where do you get it? I said I have no idea, I'll see what I can find out. That led me to Mycorrhizal Applications. And so that just kind of started our journey together, and it's been pretty good ever since. I don't want to take up too much of your time going on and on. I want to give you as much time to talk as possible. Mike Amaranthus, founder of the first commercial mycorrhizal inoculant, and I'll let you explain everything else.

3:28 Thanks, Dale. There we go, share screen.

4:01 Perfect. Well, first, thank you for the invitation. I enjoy talking about mycorrhizae. I've been involved with mycorrhizae as a researcher and a college professor for 44 years, and it's been a lot of discovery, a lot of trial and error, a lot of error at the beginning, but a lot of real successes over the last 20, 25 years. So I'll share some of that with you, and I'm looking forward to your feedback and your questions on how you feel like this could be adapted to your particular situation. I'm retired. We sold Mycorrhizal Applications in 2015, and I'm still doing some writing, some papers for journals, but I'm basically retired. I have a laboratory in my home. I still do research for the fun of it, but I'm no longer part of the company. But I do enjoy talking to people about mycorrhizae and can share some of my experience.

5:08 So today I'm going to talk about mycorrhizae as a sustainable solution to some of the problems facing farmers in today's landscape. Can you see that okay, Noah?

5:23 Yes, it looks great. Yeah, so you can see here the brown part of the screen that you see are actually root tips, and the white filaments that you see are actually the mycorrhizal fungi.

5:37 A healthy soil can have in a teaspoon of soil several miles of mycorrhizal hyphae. They're basically the roots of roots. They're the fine attachments to roots that forage in the soil for water and nutrients to bring back to the plant host. And in exchange, the plant produces photosynthetic sugars that feeds the fungus. So it's a mutually beneficial relationship. The fungus depends on the plant and the plant depends on the fungus.

6:10 I was a researcher for many years and I published over 100 papers. A lot of the scientists, we like to talk to each other. Unfortunately, it gets so full of jargon and so complicated that no one can understand what you're talking about. You publish in these real obscure journals, which again are very technical. How I want to focus my next 10 years is actually bringing information to the people on the ground where it really matters.

6:39 Mycorrhizae is not rocket science. Mycorrhizae is common to the roots of plants that chloroplasts are to the leaves of plants in natural systems. So in these natural ecosystems, mycorrhizae are very much the rule and not the exception.

6:57 Mycorrhizal fungi really have two phases. They have an external exploration phase you see on the left of the figure, and then they've got a spore production phase on the right of the picture. They explore into the soil, they're attached to the roots, they go out in this fan-like kind of array exploring for resources such as moisture and nutrients to absorb and then transport back to the plant. So they're actually doing the foraging out there and they produce powerful enzymes that can extract tightly bound nutrients in the soil such as phosphorus and iron and calcium. These enzymes actually dissolve those tightly bonded chemicals and bring it back to the plant. And then the spore production phase is sort of the babies of the fungus. When you buy inoculum, it contains root fragments that contain these spores and other structures and the spores themselves. That's actually the products that you use to inoculate.

8:04 Inside the roots, we've actually measured the biomass of well-colonized roots of agricultural plants and there's actually more fungal biomass in these roots than there is plant biomass. You can see a cross-section of a root that's been heavily colonized. You see little spider webby kind of look like little oak trees inside the roots. Well, those are the arbuscules. The important mycorrhizae for agricultural crops are called arbuscular mycorrhizal fungi. Arbuscular mycorrhizae is the colonized root. Those little spider web clouds that you see inside the root cells are actually the endomycorrhiza or arbuscular mycorrhizae. But you really don't need to know the names. Just agricultural crops primarily form with these endotypes.

8:56 There's over a hundred thousand studies of mycorrhizae. The first work was really done with nutrient uptake, primarily phosphorus. And then later, the next decade they did a lot of work on water uptake by mycorrhizae and drought resistance. But there's been a lot of documented research that shows enhanced flowering and fruiting, better yields, and improved plant establishment of plants that are transplanted with mycorrhizae.

9:25 What I want to talk about is some issues facing farmers that are maybe a little different than the typical nutrient and water kind of discussion. We'd actually talk about how mycorrhizae improved soils. Dale is a big proponent of how mycorrhizae influenced the structure of soil and soil quality. You could also say that mycorrhizae actually improve water quality by their abilities to take nutrients out of water and put it into plants instead of aquifers and groundwater. I just wrote a paper for the Fungi journal that talks about how mycorrhizae put carbon into soils, which is a big issue right now with increased levels of carbon dioxide in the atmosphere.

10:13 Talk about how mycorrhizae supply phosphorus to plants anyway just to cover some global issues. Fossil fuel use and impact—you know agriculture is a big part of that. I think agricultural produce produces more fossil fuel emissions than the transportation sector so it's a large producer of CO2.

10:43 Farmers are seeing increased costs of water and fertilizer, off-site impacts of some farm practices, there's limited expansion opportunities to increase the amount of agricultural lands and production. And this is all offset by demand for food and protein by an increasingly affluent world population that wants to eat higher on the food chain and more protein, which requires more inputs. And then the offsite impacts of agriculture that obviously concerns include changes in water quality and habitat loss and the production of greenhouse gases.

11:30 The soil health you see in the middle here is really mycorrhizae play a big part in soil health when they're present. And the mycorrhizae affect the chemical, the biological and physical part of soils and soil health obviously feeds into soil productivity which influences food quality and environmental quality. And ultimately human health is determined by the health and productivity of soils and the quality of food. So these things are all tied together. Mycorrhizae are what we consider keystone species in the health and productivity of soils.

12:10 Soil is the foundation of agriculture. When I was trained in soil science back in the early 70s, basically all they talked about was the physical properties of soils like sand, silt, clay and there was very little known about the biological aspects of soil. It was amazing how little—I mean we spent three years studying soils and an afternoon studying soil biology. So there just really wasn't very well known and there wasn't a lot of research back then on the importance of a living soil in terms of agricultural production.

12:51 In fact my first job coming out of the University of California was to be in charge of the tree production for reforestation efforts in the Pacific Northwest. And at the time we were producing like 180 million trees and they look great at the nursery for a while. They had big beautiful tops because we were fertilizing the out of these trees. So they had big tops but they had very limited root systems because we were feeding these trees so much fertilizer. And because there was so much fertilizer we had all kinds of problems with diseases. We had to fumigate the soils because there were so many problems with soil-borne pathogens. We were on this treadmill where we were spending all kinds of money to produce these trees. And then once they left the nursery and got planted in the forest and these clear cuts, we were having 60 or 70 percent mortality—60 or 70 of the trees were dying because they didn't have any root systems. I mean they looked fine but the roots looked terrible.

13:56 I kept asking the experts what to do and the experts at the time told me we'll just add more fertilizer. And it seemed like we were having more problems the more fertilizer we added because we ended up with major salt issues and so on. I finally found a professor that had an alternative way of approaching things. His name was Jim Trappy at Oregon State University. And he told me instead of adding more fertilizer to these soils that are at totally super high levels of fertility but stunted trees at this point, go on the forest and collect these mushrooms and truffles and put them in a blender and spray them over these nursery production beds. And your trees will grow normally. And I thought what the heck, who is this guy, spooky guy, you know. I thought how come I've never heard anybody even talk about this before—adding mycorrhizae to the soil to improve plant performance. But I was desperate at the time to do this so I went out in the forest and I grabbed these puffballs and these mushrooms and these truffles and put them...

15:09 Them in the blender and put them in a big 150 gallon tank and sprayed it over these beds and within two weeks these trees were grown normally and their roots began to branch and we had feeder root production again. And over time we did all 150 million trees at the time we were growing and our survival rates went up to 90 percent in the field and I was after that I mean I was just sold on mycorrhizae.

15:38 It was sort of happenstance serendipity that I found this professor and we're still friends. He's in his 90s but I mean I was hooked at that point. So I went from this pretty standard soil scientist just adding chemicals to the soil to these the real soil biologists at that point and I've never looked back.

16:00 And you know the healthy soils really are the soils that are rich with life and a lot of the problems associated with growing go away when you have a nice balance of soil organisms in the soil that are doing the heavy lifting for the ag community.

16:17 Unfortunately there's a lot of practices that actually impact mycorrhizal populations in particular in soils. Leaving soils bare the mycorrhizae depend on energy from the plant to sustain their populations and so if you have a long fallow period of bare soil or tilling you tend to reduce or in many cases eliminate mycorrhizal populations from fields so they are very fragile. The endomycorrhiza there's no septum between the cells so when you break them up into little pieces with tilling they die pretty rapidly so they're very sensitive to tilling effects and a lack of cover.

17:04 But they do play a really significant role in soil structure and stability. It's a great photo of a mycorrhizally active soil and see the sand grains all stuck together by these threads. The mycorrhizae produces sticky glue called glomalin which is a glycoprotein it's kind of an organic sugar that the mycorrhizae uses to stabilize it as it grows between soil pores and that residue that's left on in soils after the mycorrhizae turn over and form new mycorrhizae really helps stick soil particles together and it's really important in soil structure which is of course important to soil productivity because plant roots need water and air to breathe.

17:58 Just a comparison of a well-structured soil and a non-structured soil and here you can actually see a picture of the sticky glue the glomalin the green material and the glomalin is really an important carbon source in the soil but also an important structural source for promoting really good soil structure.

18:18 Just a comparison of a root profile of a massive compacted soil on the left versus a well aerated well-structured soil on the right so it makes a big difference for the roots ability and mycorrhizae ability to go out and explore the soil for nutrients and water to make it available to the plant. So it's important for accessing all of your soil as they have good soil structure well structured soil versus a platy soil.

18:50 But the mycorrhiza are also our carbon sink and a good way of taking soil carbon dioxide out of the atmosphere and fixing it in an organic source in the soil profile.

19:04 I don't think there's any question that the CO2 levels in the atmosphere are increasing dramatically. It's gone from 280 parts per million to over 400 parts per million today over in the industrial age and I think nine of the 10 hottest years have happened in the last decade so it's a big issue. I know the Paris panel for climate change and the Paris accord is calling for an increase in soil carbon content. They estimated that a point four percent, four parts per thousand increase in soil carbon would equate to 75 percent of the total total CO2 emissions released annually on the planet so it's amazing what a small increase in soil carbon could do in terms of decreasing the impact of CO2 emissions today. It's just a great opportunity.

20:09 And I know in parts of Europe they've already implemented programs to add more carbon to soil and you guys are probably bigger experts on adding carbon to soil than I am with green cover seed and all of the cover crops et cetera and minimal till.

20:28 Kinds of efforts are excellent ways of improving the carbon content of your soils, and mycorrhizae are another tool in your tool belt to do that.

20:39 So there's as much carbon in the atmosphere as equal to the same as the carbon content in the soil. There's three times as much carbon in soil than all the vegetation on earth. Soil carbon is a huge reservoir of carbon on the planet—three times as much carbon in soil than all the vegetation on earth. So how that reservoir carbon changes in the soil is a big impactor on CO2 levels in the atmosphere.

21:14 It's interesting in glacial ice they can track when they first started Mesopotamia, when they first started cultivating soils, because it released a lot of carbon dioxide even those initial attempts at cultivation. They can track the CO2 in ice based on the advent of primitive agriculture, and then of course they've been tracking it ever since, and even annually looking at CO2 levels with cultivation in the northern hemisphere.

21:48 So it's a big opportunity not only to capture CO2 but do it in a way that improves soil productivity. Thirty percent of the world's soil carbon is manufactured by mycorrhizae and associated organisms. You can see the difference between these dark soils versus the light soils, and that dark color that you get in soils, in many, in most cases, is this organic covering caused by humic residues in the soil.

22:25 It's a big part of what we see when you look at the soil and you sort of look at its productivity, and that deep dark rich color is, in a large part, due to the activity of these mycorrhizal fungi.

22:38 This is a picture of the Rodale Institute. They have this farm systems trial. Many of you may have heard about the trial or seen the data. They compared conventional agricultural methods with organic methods, which include cover crops, compost additions, and mycorrhizal fungi, and in 20 years you can see the difference between the conventional soil on the left and the organic soil on the right. In that Rodale Institute study they added a thousand pounds of carbon per acre per year to their soil with the organic methods, and if you multiply that over millions of acres of farmland in North America, it adds up very quickly in terms of its impact on CO2 emissions.

23:29 I want to talk a little bit about mycorrhizae and water quality. Mycorrhizae, they create this basically this web in the soil, and they can act as a net to prevent the ability of nutrients to leach out of the soil. They're basically a lifeline from the roots into the soil, and they can extract a lot of nutrients before they go into groundwater or wash into lakes and streams. So it's the way natural systems prevent nutrient loss.

24:10 Natural ecosystems are famous for their ability to recycle nutrients and not have losses of nutrients into waterways, and a lot of that is the web of life, the soil biology that keeps all the nutrients on site.

24:29 There's a need to deliver nutrients more efficiently. First of all, fertilizers are expensive, and about half the nitrogen fertilizer that's used is not utilized by plants. So you've got a lot of leachates going into the Mississippi River basin and ultimately to the Gulf of Mexico, and it's created this huge hypoxia zone that extends from Texas to Florida where the nutrients cause bloom of algae, and when the algae decomposes, it utilizes the oxygen in the water. So there's no oxygen available for aquatic life.

25:10 One pound of phosphorus in the water produces 250 pounds of algae. So any way we can minimize the movement of nitrogen and phosphorus into waterways is going to reduce algae production and ultimately help protect aquatic systems. And if you really had to pay to process to take all these nutrients out of water, it'd be extremely expensive. It's a lot more cost effective to reduce the amount of nutrients going into these waterways, and it is to clean up water, which is a very expensive process.

25:50 Interesting about 2003, I worked with researchers at the University of California and we actually demonstrated the red areas you see are these are actually in the movement of amino acids into a fungal hypha here. And the mycorrhizal fungi have this unique ability to actually absorb organic nutrients out of the soil in this case in the form of arginine and glycine amino acids.

26:18 So the ability of mycorrhizal fungi that are attached to the roots to uptake organic forms of nitrogen is a huge advantage to the plant. You want to get as much nitrogen as possible in the plant and doing it in the organic phase is a lot less leachable than the nitrate stage which tends to end up in water sources. So this is a great advantage for crops to have the ability to take nitrogen out of organic matter in an organic phase and use it for productivity plant growth and productivity.

27:01 And we participated in a few studies where we looked at different rates of fertilization and the red areas are the amount of nitrates ammonium and phosphate actually leached into these lysometers, these little catchment basements we had at the bottom of the pots. And the green areas was the amount of nutrients we caught in mycorrhizal systems compared to the orange, the brown bars which are the system. But I mean we showed between a 30 and 50 reduction at the full rate of fertilizer in the amount of nutrients being lost out of the system which is significant and other researchers have had similar results from similar studies.

27:53 If we captured all our fertility on site we wouldn't have to use as much fertilizer. I think this is pretty well documented. This is actually lemon on the left with no nutrients. Obviously you can't grow plants without nutrients very effectively, but here's the half the nutrient rates and you can see the plants on the right were treated with mycorrhizae with half the nutrient levels and at the full nutrient level there's really very little difference in the terms of productivity between mycorrhizae grown at half nutrient level and mycorrhizae growing at the full nutrient level. And we've seen this a lot with farmers where they can cut their fertility, you know, 20 to 40 to 50 depending on their soil conditions and see the same productivity with at a fraction of the cost of fertilizer because many of these soils are already rich with fertilizer. It's just the plant can't access those nutrients in the soil because it doesn't have this extended root system.

28:56 And I know Green Cover Seed promotes use of cover crops and that really benefits the soil because you're pumping energy into the soil for all kinds of critters in the soil, not only mycorrhizal fungi but other beneficial insects, which create like a root mycorrhizal canopy which really keeps the soils well aggregated, keeps pumping carbon in the soils, support the activities of these biological organisms and improves the ability of soils to capture nutrients and prevent nutrient losses.

29:37 It was really the first worldwide web. And it's amazing how much biomass is being produced beneath the soil surface. You can actually see the mycorrhizae with a 20 or 30 power microscope. You can see the sticky little threads on the microscope so it doesn't really require expensive equipment. If you dig in your soils you can by pulling the soil out you can see how the soil particles sort of are stuck to the roots or just off the roots. That's a good sign that you've got healthy soils and a lot of mycorrhizal activity.

30:16 I want to talk a little bit about phosphorus. Phosphorus is one of those nutrients that's tightly balanced in the soil. The mycorrhizae produce an enzyme called phosphatase which is very good at dissolving phosphorus in a mineral form and making it available for absorption by the mycorrhizal filaments. About 15 percent of the phosphorus that's in the soil is actually utilized by plants annually so 85 percent is not available. And they usually roots alone without the mycorrhizae only use phosphorus in this narrow band of about one to two millimeters surrounding the soil root surfaces so it's not very good at exploring pools of phosphorus in the soil.

31:05 That are beyond the app where the roots are actually residing and phosphorus is the finite non-renewable resource. It's mined and it's estimated that U.S. phosphorus reserves will be used up by 2050. So it's a non-renewable resource. We got to be pretty clever about how we can serve phosphorus considering it's not a, it's not a renewable resource.

31:37 And as we have increased demands for food and fiber in the next three to four decades, it's going to take a lot of phosphorus to produce those plants that we need in the quantities that we need. So the big question is do we have enough phosphorus to feed future generations? It's just the phosphorous production curve. We're at the almost at the peak now, 2021. And the phosphorus supply is likely to decline as the reserves decline over time, and the peak phosphorus production is supposed to happen in 2033. Morocco, I think, is the biggest reservoir of phosphorus in the world, and the U.S. supply is supposed to be depleted largely by 2050.

32:32 So we really want to rely on foreign countries for our phosphorus fertilizer? I think that's kind of a bad, both politically and economically for the people in the food production services.

32:47 This is what phosphorus looks like in your soil. This is a calcium phosphate crystal. You see they're like little rocks, and so mycorrhizae by squirting these enzymes on these rocks actually dissolve the rocks and then it absorbs the phosphorus out of those calcium phosphate bonds. Absorbs them into the mycorrhizal threads and then transports it back to the plant roots.

33:11 Just some mycorrhizal colonies and some petri dishes with different forms of insoluble phosphorus. And these halos around these colonies are where the mycorrhiza is producing the enzyme to dissolve the phosphorus to make it available. And in these boxes without mycorrhizae, the narrow phosphorous depletions is zoned versus the roots with endomycorrhizae. You can see the mycorrhizae by getting out to these pools can actually search for pools of phosphorus and use the enzymes to unleash the phosphorus for the plant. This is very similar to iron, manganese and calcium. There's calcium phosphatase that's also used to break calcium apart.

33:59 And some agricultural practices use tremendous amounts of phosphorus like potato production, and we can really conserve the amount of phosphorus that we have to put into these systems and reduce the offsite impacts of these huge amounts of phosphorus that are in the system by adding mycorrhizae to these production fields.

34:24 This is where, like I said, I've been involved in with mycorrhizae for 43 years, actually a little bit longer than that. I started growing mycorrhizal inoculum in my garage for some of the field trials that we were doing. There was no commercial sources for mycorrhizal fungi, so we would basically grow it in our garage for the studies. And I really grew to like it and enjoy that part of the science is producing mycorrhizae. So it goes back a long time with me, and this is where it all started. By the end, I think mycorrhizal applications was producing over a million pounds in St. Louis, Oregon and India. But this is where it all started in my garage about 37 years ago or so.

35:22 And this is what, this is how it looks like in the production phase of the mycorrhizae. You can see these roots here and then the threads are the mycorrhizal hyphae, and then the little balls that you see are the spores being produced. So this is a production bag, what's going on inside the bag.

35:42 Electron micrograph of what this looks like under higher magnification. This is a 600 times photograph of a root. You see this spores or the seeds of the mycorrhizae bursting out of the root. It's what it looks like. It more like a hundred power. It's probably 75 power here. The root fragment. You can see all the mycorrhizal spores packed into the root fragment.

41:16 Tool to solving some of the world's environmental problems, and some of these regenerative ag farms are really improving their soil conditions and their productivity at the same time. So it's not either or—it's not a zero-sum where something has plus one, something else has minus one. You can use this one plus one equals three: symbiosis or synergistic effect. And it's more about understanding the whole process.

41:50 Like we needed quality production of mycorrhizal inoculant, and I think there are some companies that are doing that based on what I've seen in these products. There's some good companies producing quality products, and you can formulate it for different kinds of crops. You can use different species of mycorrhizal fungi—I mean, there's a lot of research now into individual species and what they might do in terms of creating more of a beneficial effect.

42:21 And then you need technical support—you need people like Green Cover Seed that are out there meeting with the farmers and looking at the particular problems and issues to make sure you've got the right formulation and a concentrated formulation that's going to work for your conditions out there and make it easier to apply.

42:46 So thank you—I know I ran through that pretty fast. I'm probably pretty excited about answering some individual questions out there. We used to have a motto at Mycorrhizal Applications: 'To change your world.' And I think in a large way, the inoculum production can be a tool for farmers to utilize to change the world.

43:10 And if you're looking for more information, I think mycorrhizae.com is the Valence mycorrhizal application site—it's a good source of information on mycorrhizae. Data has been with the company since the very beginning. She's a good resource for information and studies for particular crops. And mycorrhizalonline.com is another option for people needing smaller amounts of mycorrhizae. Talk to Zachary down there—they're a good source of information and a good source of inoculum for smaller-scale kinds of projects.

43:52 With that, I'll turn it back over to Noah and Dale. Thanks for your attention—appreciate it.

43:59 Yeah, thank you. We've got already quite a few questions here, so we'll probably just dive right into those for the next 15 minutes or so. Randy asks: how deep of tillage affects mycorrhizae? Shallow versus deep?

44:17 Generally, the mycorrhizae population is 90 percent in the top four to six inches. So if you're tilling that deep, you are adversely affecting about 90 percent of your population. I have seen examples where they survived at lower depths and then grown back up into the surface if conditions were right, but if you're tilling four to six inches deep, you're eliminating most of the population.

44:48 Can you apply mycorrhizae as a seed treatment as well as a fungicide, or is that counterintuitive? Well, somehow Dale is more of an expert on this than anybody, but there are certain fungicides that are present on seed that do not affect mycorrhizal fungi. Yeah, they have a pretty good list that Valence has that can tell you which fungicides adversely affect. Many do not affect mycorrhizae, yeah, so there's an option.

45:20 And you know, I've always been a proponent for putting mycorrhizae on seed. It's a very inexpensive way to do it—the seed is the carrier. The mycorrhizae, there's a little bit of phosphorus in seed, so when the seed germinates, it'll use the phosphorus that's stored in the seed. And then the seedling, once it uses all that phosphorus, the young seedling will actually go through a stunted phase where it doesn't have enough of a root system to get phosphorus out of the soil. That's why you usually put phosphorus down in a band right next to the seed so they can more quickly access the phosphorus in the soil. So by putting the mycorrhizae on the seed, the mycorrhizals right where it needs to be. Those first few feeder roots the seed will produce exudates that cause the mycorrhizal spores or seeds to germinate. So the closer you get the mycorrhizae to—

46:14 The seed and the emerging root system, the more successful the and the quicker the relationship. So I'm a big promoter, probably putting my horizon on Steve.

46:24 Yes, I can answer the interaction between seed treatment and mycorrhizal fungi. There's about oh I don't know about 10 different modes of action that affect or that are used in seed treatment fungicides. Of those I know about eight out of the ten, roughly or have zero or actually sometimes even a stimulatory effect on mycorrhizal fungi.

46:59 The two fungicide classes and this would include both seed treatment and foliar that do harm mycorrhizal fungi: benamil or ben late, which is used in vegetable crops, it is not used in field crops, is highly toxic to mycorrhizal fungi. And so is captain. And now captain is not toxic as a seed treatment, it is, but like with everything else the dose makes the poison. So you just cannot get enough on the seed. It doesn't move very far from the seed and so you've got this little tiny toxic area, but they occupy a very tiny portion of the total soil.

48:03 Captain is toxic in furrow but not on the seed and there are no field crops in which we apply captain in furrow. Benamil, now that's not to say that some of these foliar fungicides, the foliar fungicides we typically use, the strobo learns and the tetrazoles, they can affect some of your other beneficial fungi but do not move down to the roots or through the soil to affect mycorrhizal fungi.

48:43 So if you do have fungicide treated seed that is not an issue with mycorrhizal fact. None of the commercial seed treatments affect colonization of mycorrhizal fungi.

49:00 Dennis has I'm looking to better understand the benchmarks or the indicators and how to use them. For example he says the total live microbial biomass or a sap analysis. I've heard that we should reach 6000 grams or nanograms before trying to decrease synthetic inputs. Can you touch on kind of benchmarks on how to gauge where you're at and there was even some questions about how to test that as well?

49:25 Yeah those tests really don't aren't in aren't good to determine your mycorrhizal populations. So I can't address that particular level and what that might mean. But there's a simple colonization test for mycorrhizal fungi and the cost is not that high to determine what your mycorrhizal percentages are on your roots.

49:51 But the best measure is this colonization test and basically what the lab will do is it takes a cross section of maybe half inch of feeder roots and they cook it in koa, potassium hydroxide, it clears all the tannins out of the roots. And then they stain it with the best is just indian ink. So they'll soak the roots, the clear roots in indian ink and the chitin in the mycorrhizal tissue picks up the indian ink and you look at the percentage of your root that's colonized by a mycorrhizal fungi and it's in a petri dish with a grid and every time the root crosses the grid line you mark whether or not it's got mycorrhizal structures in it.

50:42 So say if you've got 100 roots in your plate and 50 of the intersections of those 100 potential intersections have mycorrhizae and you're 50 colonized, which is really high level for agricultural areas. So it's a simple test, it's less than 100 bucks, it's reliable, it's repeatable and there are several labs that do it now.

51:09 So that's the best test in terms of of micro fungal populations. In terms of like the mycorrhizal population, yeah and Ward Laboratories, which a lot of our customers use because they're right in our backyard here, Ward Laboratories is offering a mycorrhizal colonization test and I think they're doing it for I don't know what they're charging for that, my understanding is they're very reasonable with it.

51:36 So the thing too when you get your results back is that most of the benefits of the mycorrhizal relationship occurs when 20 percent of the root is colonized. So if you get

51:53 You know a level of five percent colonization that's inaccurate and inadequate, and you'll get a big increase in productivity in your plants by going from five percent to twenty percent. But if you're at thirty five percent to fifty percent, you're not gonna see any difference in plant productivity at those levels. So you really wanna get up to that twenty level and you'll see noticeable gains in plant productivity by trying to get up to that twenty level. So if you get results back and says twenty two colonized, you're good. That's not a bad level, that's a good level because there's of course roots that don't get colonized. You're looking at the root lengths and stuff. Usually by twenty, that's a good level in terms of plant production.

52:46 If one is planting covers and no-tills every year, how long does one need to add mycorrhizae fungi? Well, again Dale probably has more practical experience than I do, but you probably only have to do it once and just occasionally monitor your populations.

53:03 I would agree with that. As long as you can keep live roots in front of it. I've seen some studies on fallow periods how long of a fallow period. Someone else asked a question, what other than telogen chemicals are detrimental? Fallow is very detrimental. I've seen some research that a fallow period, especially during the summer when things are respirating rapidly, that a fallow period of more than a month will basically kill it off. So as long as you are continually cropping and not having fallow periods, you can maintain it indefinitely.

53:56 I had two questions about the effects of glyphosate. Well, it's been mixed. It can be negative. You look at the literature and there's a lot of studies and the results have been really mixed. It's one of those things where I don't know if it's the soil conditions or the level glyphosate or what the issues is, but Dale might have more geographically a better information for the Midwest.

54:29 Yeah, what I have seen, and like you said, the research results are mixed. Some people say it kills it all and others say has no effect. When I started sorting those, it appeared the researcher had either had an agenda to prove that glyphosate is harmless or glyphosate is evil. When you have a roundup ready crop that tolerates glyphosate, the mycorrhizal fungi don't seem to be affected. However, if you have mycorrhizal fungi on a crop or a plant susceptible to glyphosate, it kills the hyphy. If you killed it with tillage, you would also kill the hyphy. It appears to be more of the loss of the host plant rather than a direct toxicity of the glyphosate.

55:40 I even saw one study where there was a pretty significant increase in mycorrhizal colonization due to glyphosate applications on roundup ready crops. And the only thing I can explain that outcome is that when crops become deficient in certain nutrients, they will release the signaling compound that trigger colonization. There's quite a bit of evidence that when you apply glyphosate to roundup ready crops, they become deficient because it ties up some of the pathways that are responsible for moving micronutrients within the plant. So applying roundup to a roundup ready crop will usually trigger a micronutrient deficiency for a period, and that may actually trigger more of the signaling compounds to increase colonization. It's not a huge effect, but I think the bottom line is that if you are inoculating roundup ready crops, supplying roundup isn't going to hurt them. And if you are applying roundup to susceptible plants, you can have some issues with mycorrhizal fungi. But again, it's the fallow period that it's the death of the host plant that is the far greater concern rather than direct toxicity of glyphosate.

57:25 Okay, when picking out an inoculant, what are some things to consider or look out for when selecting which one to choose?

57:33 Well I think the big thing is the concentration in the application. So you don't want it if it's a seed, some of the inoculums are seed coatings and they're formulated in terms of their concentration and the sticker, etc. to be used for that application. So make sure that you're using it correctly based on what it's used for.

57:58 I've seen like people use granular inoculum and just spread it on the surface of their soil. And even though the granular inoculum was pretty high quality, the fact that it's not going to do very well on the surfaces. So it's got to get down where the root activity is. So make sure it's not just that it's used appropriately. I think that's the biggest thing—is that sometimes they're not used in the right way and you know you want to get as close to the root systems as possible.

58:29 Okay, I have time here for one more question. You kind of mentioned the rates on that, but what rate are you looking for and then what's the best way to apply those to the seed? Well Dale might want to comment on you know the rates used for cover crops. I know that different plants have different mycorrhizal affinities and so the rate would really depend on the mycorrhizal. Like all the legumes love mycorrhizae, so you tend to be, you can kind of use less inoculum because there's a lot of affinity between the plant need and the mycorrhizal inoculum.

59:14 You could add a million propagules per square inch for a canola field and you're not going to get any mycorrhizae because canola doesn't form the relationship with the mycorrhizal plants. And there's some plants that only form a weak relationship. So in terms of the cover crops, what are you recommending Dale? And I know we used to recommend, but you may have refined it.

59:34 Yeah, I mean we're still going with 90 to 100,000 propagules per acre. Just like with any other crop, you know, we just with 150 different species of cover crops, it's an infinite number of mixtures—5, 6, 10, 20 species in a mix. It's just impossible to develop different recommendations for all those combinations. So what you're trying to do is you're just trying to use the seed as a carrier to get good distribution across the acre.

1:00:14 So what will happen is that the mycorrhizal activity, once it starts, will spread from plant root to plant root. So those threads, as it goes out from one root, will grow across to an uncolonized root and link the mycorrhizae between plants. So you're growing plants in a row, they'll grow up and down the row and then cross over between rows and colonize it. So you're really using the seed as a carrier to get good distribution across that field.

1:00:49 So as the growing season goes on, the mycorrhizal spreads through the field. We've seen that, you know, for decades.

1:00:58 Yeah, well, with that we'll wrap up. I know there's a couple questions that I didn't get to. Feel free to email those to me if you want those answered. I can pass those on to Dr. Mike. So my email is just noah@greencoverseed.com, and I believe your contact info was there at that last slide as well, Mike. So if you want to just email him directly you can do that as well.

1:01:24 Next week we've got Rob Myers. We'll be going over cover crops and the economics of improving your bottom line using those cover crops. So we're excited to wrap up season three. But Mike, thank you so much for your time this evening. That was very informative. I learned a lot, so I appreciate that.

1:01:44 And do you have any final final words of wisdom for us this week? Well, you guys are the experts on your situation and stuff. So it's not rocket science. And there's some really good available information online, or you know, email us if you have particular questions. But I think part the whole agricultural community are the experts and it's really an opportunity to do something really good for the farm and for the environment.

1:02:15 Absolutely. Yeah, well thanks again for your time. I really appreciate that. If there are people on here that you want to share this with—your family or your friends or maybe it's a landlord—we are recording this. So I'll have this posted later in the week that you can share with your friends. And thanks again Mike for your time.

1:02:31 Thank you Dale, and we'll see you guys all next week. All right, thank you. Take care. Email those questions. Absolutely. Yep. Take care, you guys.