How Soil Microbes Communicate: The Secrets of the Soil Sociobiome

0:00 Let them in.

0:14 Okay well welcome everyone we're going to give it about 30 seconds just to let everyone else in, and I'm also going to get this ready on Facebook, and we'll be ready to kick things off.

0:40 Okay well welcome everyone today for part one of our four-part series. Keith and I sat back and looked at all the webinars that we'd done and found that probably one of the most questions that came out of a webinar was the phosphorus paradox with Dr. Christine Jones, and just had a lot of great comments, some really good feedback from people saying that was excellent but it brought up a lot more questions. We needed some more in-depth details on a lot of the things that Dr. Jones is bringing up, and I know for me personally it kind of felt like you're peeling back a layer of an onion without knowing what the whole system is like. And I know that Christine you've alluded to that as well, the jigsaw puzzle, you know it's hard to see that whole picture.

1:28 So we wanted to make this a more in-depth kind of series. What we're going to do is focus on four different things each week, and we will have everything recorded so if you have to miss any of these for any reason they'll be on our website and on our YouTube page. The other thing that we wanted to do was include more Q&A at the end of this and just provide more time for you guys to ask those questions that you have. In addition to the longer presentations, what we're going to do is let Dr. Jones go for an hour till 6:30, and then we'll open it up to your audience questions. If you have any of those you can type those out in the chat bar, and we'll go from there. With that, Keith do you want to go ahead and introduce our speaker?

2:10 Yeah, thanks Noah. Well, like Noah said, we're just extremely proud and thrilled to have Dr. Christine Jones not only be with us again but to be with us for four sessions in a row. Very excited about it. Many of you have heard Dr. Jones before, and that's why we have so many people logging in. Just absolutely one of the top soil microbiologists, soil ecologists in the world. She is from Australia, and they are experiencing a little rain shower over there so she's excited about getting a little drink for her garden. But she's been over here to the States many times and has been here to our farm numerous times as well. So we just have the utmost respect not only for her as a person but certainly her as a scientist and the knowledge that she brings.

3:03 And one of the things that we really appreciate about her is that even though she's a scientist that knows all these sciencey things, she really speaks farmer language and it resonates with the producer. And so that's one of the things that we've just always enjoyed about her is how practical she is and the information that she's bringing to the table. So with that I'm going to get out of the way and I'm going to jump right in and listen with everybody else, because this topic today, the talk today, is a brand new one that I have never heard. So I'm really excited about hearing it. Dr. Jones, take it away.

3:44 Thank you very much Keith and thank you Noah, and great to meet everybody online. I've had a go at this. It's called The Secrets of the Soil Sociobiome. So I've been reading all kinds of really in-depth ecological articles about the science of how microbes communicate with each other and communicate with plants and how plants communicate with each other. And then I thought, now how am I going to put this into something that actually translates to something that's understandable? So I've had a go, and this is the first time I've actually given this webinar as well: The Secrets of the Soil Sociobiome. So we'll see how we go.

4:35 Sharing screen with the technology. It just takes a little minute. Sorry to come on. Move away, it's not letting me do it.

4:54 You are screen sharing. Yeah, I know that. What's the matter now? I can't get into the bit that I need to get into. Go away. Would you believe this? Sorry everybody, it's not actually letting me. There's something up the top. I can't get in.

5:31 Okay, let's see what happens if we do this. Can you see that? Can you see that? Yes. I'm really sorry, I don't know why all the icons that normally show up the top didn't want to show for me. So let's just see if I can now. Is that the next one? You can see the next one?

5:54 It says soil is by far the most biologically diverse material on Earth. Okay, so we're away. All right, Secrets of the Soil Sociobiome. So soil is incredibly biologically diverse and it's got all kinds of critters in it. I'm sure that everybody that's watching this today recognizes this fact that there are all kinds of amazing things in soil. It really is the last frontier when it comes to science and biodiversity. In all of our ecosystems, not just in our soil, biodiversity is actually the key factor in the effective functioning of living systems. It doesn't matter whether we're talking about the ocean or a forest or on our farms or in the soil, biodiversity is actually the key factor. We're realizing more and more as we look into the science of these things, and in terms of soil biodiversity, it is so important for nutrient cycling, for moisture retention, for resistance to pests and diseases, for crop and pasture productivity, for food security, landscape function. In terms of, we were just chatting before this session started about Australia's just had massive droughts and then massive floods. And it's also very important for carbon sequestration.

7:07 I'm not going to go into any of those things in any particular detail today. I mean, I'm sure you're all very well aware of why soil biodiversity is important. We're just going to go on and actually look a little bit more into, well, basically the secrets of the soil microbiome. But the Food and Agriculture Organization of the United States has estimated that the socioeconomic value of soil biodiversity exceeds 1,542 billion dollars. Which all I can say about that is that it's an awful lot of money. But in other words, this is very valuable for the things that are going on in the soil that we really don't know very much about are very important for us. So far so good. Soil biodiversity is important. Even the Food and Agriculture Organisation has recognised that it's worth its worst dollars.

7:57 But how do you get it? This is the practical part of the equation. How do we know that we have biodiversity in our soil? And if we don't have it, how do we get it? Well, there's lots of issues with trying to figure out what's actually going on in our soil. One of those is that less than one percent of soil microbes are culturable. And what that means is that you can take some soil and you could put it into petri dishes in a laboratory or something, and you could provide food for microbes, and less than one percent of the microbes that were in that soil would actually grow in that medium. So we can't culture them in a laboratory. We can't study them. It makes it very, very hard to know what is actually in your soil if 99 at least of the microbes there refuse to cooperate in terms of allowing us to study them. So number one, they can't be cultured in a lab, most soil microbes. And number two, the.

8:56 Majority of microbes in the soil at any one time are actually in a non-active state. In other words, they're dormant, which again makes it very hard to be able to detect unless they've been activated by something.

9:10 So the soil microbiome or the soil sociobiome is very difficult to study, and that difficulty has led us up several garden paths or taken us down the wrong track many times. We've had to rely on models and we still are relying on models to some extent to try and model what is actually going on in the soil. And the models that we've used in the past haven't really been correct because we haven't had the technical skills to actually detect what was in the soil.

9:41 Now in 1987 there was a paper published which is called the classic soil food web model. H.W. Hunt was the lead author of that, but there were quite a few authors on that paper. And that classic food web model unfortunately is still being used and still appears actually in a lot of USDA publications, but it was theoretical, was based on estimates. It was basically a theoretical calculation of the nitrogen transformations that take place in the soil through what was called the detrital food web, or if you like the decomposer pathway in the soil.

10:18 In other words, you have certain organic compounds in soil like soil organic matter for example, and it's broken down initially by fauna in the soil, and it's sort of broken into smaller and smaller components and goes through basically a food web where everything eats everything else. And nitrogen was thought to be released in the soil through that pathway. And some nitrogen definitely is released into soil through that pathway, but it is not the main pathway in soil.

10:51 And I'm going to talk about nitrogen in a couple of weeks time. We've got this going to be a webinar called the Nitrogen Solution, and I'll go into that in more detail. But we have become really hung up on this classical soil food web model, which in actual fact is now being shown through the advances in technology we have now is substantially revised. So there are lots of articles about soil food web revisited and soil food web challenged, et cetera.

11:26 So empirical studies—in other words, where we really do have data to go by—have found that if we're looking at carbon cycling, if we're looking at nitrogen transformations in soil, that most of these take place through the fungal energy channel. So it's not through the herbivory of bacteria, for example. Some does go through that channel, but the fungal energy channel is the one that's really important.

11:50 And the fungal energy channel, the main fungal energy channel, begins with labile carbon in the form of plant root exudates. In other words, we're talking about hundreds or sometimes even thousands of different carbon compounds that come out of plant roots for various reasons—sometimes to feed microbes, sometimes to signal to microbes. And how do we know that that fungal energy channel is operating? We look to see whether the roots of our plants have rhizosheaths. In other words, whether they have soil sticking to the roots. And then we know that that fungal energy channel is actually open and that the plant is actually channeling energy out into the soil ecosystem.

12:32 I've showed this slide many many times and I probably will show it many more times because it's one of my favorites. This is a high magnification photograph of what that actually looks like inside a rhizosheath. You can see there are lots of fungal hyphae in there, and they're not necessarily symbiotic fungi. In other words, they're not necessarily mycorrhizal fungi or Trichoderma or other fungi that form a very close relationship with plants.

13:04 The more research that's been conducted, the more we've been able to see that a lot of them are what are called saprotrophic fungi. So they're basically just feeding off those sugars that are coming out of plants. And it has been thought under the classic food web model that fungi derive most of their energy from sort of lignaceous material or materials that are difficult to decompose, like woody materials and things that the bacteria, for example, are not able to access. That's thought to have been the fungal pathway. And certainly you do see fungi decomposing those kinds of material.

13:42 And then it has been thought, well, if you wanted to have more fungi in the soil, you would have to have more of those less readily decomposable type materials in your soil. Well, the science shows that in fact the most prominent fungal energy channel is actually labile carbon—the kind of carbon that was thought to be what bacteria feed on. It feeds enormous numbers of fungi and many varieties of fungi.

14:11 And the more we look into it, the more we realize that these saprotrophic fungi are very very important, and they are moving carbon or moving labile carbon away from plant roots out into the soil food web as well—not just using it for themselves, but also feeding bacterial colonies. And in fact, we now know that the hyphae of fungi have their own bacterial rhizosphere, if you like. In the same way that plant roots have a sort of a coating of bacteria around them—bacteria that are actually feeding on exudates from the plant roots—the fungal hyphae that are associated with plant roots also have a coating, like a biofilm of bacteria around them, that are feeding on exudates from those hyphae themselves.

14:58 So the hyphae exude carbon as well as the roots exceeding carbon. So it's worlds within worlds. The closer we look, the more we see. And this is a lovely—I think I did show this one in the Phosphorus Paradox—a high magnification view of plant root with all the exudates around it. And you can see some of these droplets of exudate here are being cradled by fungal hyphae.

15:24 Now they could be any kinds of fungi. There's a whole lot of really beneficial fungi around plant roots unless we're using fungicides, of course. And it has been shown that fungicides of all the poisons that you would use on plants, fungicides are the most detrimental to the soil because, of course, they are preventing this entire fungal energy channel from even getting started.

15:49 And this is a very very well known slide. I've used it hundreds of times. Other people around the world use it hundreds of times from the Aberdeen Mycorrhizae Research Group. It's quite an old slide, but it just very neatly demonstrates how the hyphae, in this case of arbuscular mycorrhizal fungi, can move energy that's coming from photosynthesis being channeled into the soil by plant roots and can actually distribute that. They are the highway and the internet of the soil.

16:19 And we know this about mycorrhizal fungi, but we have to start thinking about lots of other kinds of fungi as well that we can't see as easily as we can see these ectomycorrhizal. And it's a close-up of a plant root coming down the center of the photograph here, and then everything else that you can see in that photograph—either hyphae of, in this case, ectomycorrhizal fungi—but they can certainly have a wonderful network throughout the soil.

16:48 So this fungal energy channel is the key pathway to support biodiversity in the soil because these fungal hyphae are keeping most other soil organisms alive through their energy networks and also joining plants through common mycorrhizal networks.

17:08 If I have time at the end of the presentation today I'll just give a little example of that, but messages can be transmitted from one plant to another through these highful networks as well as energy as well as water and nutrients. So the whole process of photosynthesis and plant root exudates are recognized as constituting the primary pathway for soil building.

17:32 So if you're still thinking in terms of the classic soil food web model, you need to just put that one aside and think about this fungal energy channel. So here we have a plant in the center of the diagram here with the root exudates coming down this primary pathway. The exudates do have to move through the microbial pool and talk about microorganisms a little bit more in a while, and this is at this stage it's all labile carbon.

18:00 But it is going to be processed through the soil microbiome and we want it to end up as being stable soil carbon down here. And our fungi and bacteria in this instance that's being called the microbial carbon pump are very important for the transformations that take place.

18:17 So over here on the left hand side where we have leaf litter and decomposing roots and there might be animal manures or there could be compost or whatever the sorts of organic matter actual matter itself that's composed of lignin and cellulose and hemicellulose, that decomposition pathway does feed into the stable carbon pathway in the form of the enzymes that microbes use while they're decomposing these materials can actually stimulate this other liquid carbon pathway, but it is peripheral to the main pathway. It's important, but what's happened now, you know, this is crazy, I've actually lost...

19:20 I must have touched something. Noah, I don't know what to do now. Is it just frozen? No, I think I must have moved my pointer and touched something. It's come up with a Zoom message that's got a leader in the 2020 Gartner magic quadrant meeting solutions. I think I might have to stop share. What could you guys, if you need to stop sharing here, I can maybe and then I'll have to stop share screen again. Maybe no, can you get rid of that what's in the background? Let me see if I can bring this up here, we go. Slideshow. I don't know why I'm having all these technical problems. There we go, should be right now, as long as I don't press on the wrong thing again. Can you see that now? Yes, yep, looks good on our end. Okay.

20:21 So here's a close-up of Scott Ravencamp holding a plant that's an old plant that's had lots of exudates coming out of the roots and it's created wonderful transformation for this soil which over here on the left hand side you can see that the soil in the absence of plants is very compacted and doesn't have any structure. So one of the important things about these exudates is what they can do to soil structure.

20:44 This is a highly magnified view actually of some sand that's been incredibly improved through soil fungi being supported through the soil through the liquid carbon pathway. So this soil has got nothing to do, this soil has had no plant residues or any organic matter added to it. The structure is just improved with fungal hyphae and the fungal energy channel. Over on the right hand side we have soil that's well aggregated through that pathway, and on the left hand side we have compacted soil where if our soil particles haven't been pulled together with fungal hyphae then we won't have those lovely spaces between them for air and water to pass through.

21:25 So we know that plant root inputs build carbon five to thirty times faster than carbon derived from above ground biomass, and this above ground biomass is of course the basis of the classical soil food web model which has now been let's just say revised. So when our fungal energy channel is operating, this is a photo from Derrick Axton's farm. It's a little durum wheat plant at a very young stage of growth. The seed is just here under my pointer. We have this fantastic seminal root system that's getting down really deep in a very short amount of time and great rises sheaths on the crown roots here of this plant.

22:09 And these plant root inputs, they're really the only way that we can build carbonate depth. We can put organic materials like we can have our crop residues near the soil surface or we can add compost or something at the soil surface, but if we want to build soils at depths, in this case we're looking at about twelve inches of depth, then we have to have plant roots at that depth and we have to have plant roots that are actively exceeding label carbon for that fungal energy channel.

22:37 So why have I used the term the soil sociobiome for today's webinar? Well, it's because what is actually happening in that soil that we can't see, when we look at it we just, well, basically we see a whole heap of dirt, I guess, is that we can't see unless we're looking for riser sheaths. We can't see that there's interactions taking place between plants and microbes and there's also many interactions taking place between microbes and plants. And I will give an example of one of those right at the end. And multiple interactions taking place between microbes and microbes. There's all these different levels of things going on in the soil and really it is a social world. It's unbelievable the amount of the chemical messages, the biochemical messages and the signals. There's probably thousands of scientific articles now published on just exactly how all of that messaging works in the soil.

23:41 But all of the interactions between plants and plants, plants and microbes, microbes and plants, and microbes and microbes, they all involve biochemical signaling. So you have to think of it in terms of these mostly single-celled things in the soil, little tiny cells too small for us to be able to see with the naked eye. And of course microbes can't see, they can't hear anything. They can't smell anything. I mean, you know, they don't have any of the senses that we as a human being have to be able to detect our environment and react, respond to our environment. The only thing that they can respond to, they can respond to temperature, they can respond to moisture, and they can respond to biochemical signaling. And the biochemical signals enable a microbe to know where it is in the soil and what it is that it needs to do, what its neighbors are, how many of them there are, and enables microbes to actually coordinate their behavior and achieve all kinds of amazing things in the soil like building aggregates for example or bringing nutrients to plants.

24:54 And these biochemical signals are very complex. There are thousands of them and it's really quite an extraordinary world. I don't know any simple way to explain it really, other than there are every biochemical signal has a different shape in it's a shape in terms of what it's made from, the atoms that it's made from, the elements that it's made from. And those shapes will fit into receptor sites both in the microbes that generated them and in other microbes that are able to receive them. And this is exactly the same way that biochemical signaling takes place in the human body or in any living system.

25:37 is that there will be biochemicals produced and organs if you like or cells that are able to either read those chemical signals or ignore them and if there is a receptor site then the signals can be read. I think I'll probably just leave it at that, but this is basically how the thousands of different chemicals are sorted in the soil. As you know, when there are so many things living in the soil and so many things, the only way that they can communicate with each other is through biochemical signals. It's just absolutely extraordinary how it all works.

26:18 But when you stop and think about it, it works the same way in our bodies, in our human bodies we have, you know, there's hundreds of different biochemicals floating around right now that are telling your liver what to do and kidney what to do and your heart what to do. And it's all regulated at that level without us really having to think about it.

26:38 But what we do know about plants now with the technology that we do have and the fact that we're able to interpret some of these signals is that plants function at their best when there is many different kinds of microbes living around their roots. And the best way to achieve that is by having many different kinds of plants growing together, because when we have them, every kind of plant is obviously supporting different kinds of microbes. And when we have the plants growing together, we want them to actually, we want root mingling. In other words, we want the roots to be mingled in the soil. They don't necessarily have to be touching each other, but the plants have to be close enough for the mycorrhizal fungi to be able to link them together in a common mycorrhizal network.

27:25 And even though there are plants that are not mycorrhizal, like brassicas for example, provided they're in a mix with other kinds of plants that are mycorrhizal, they will join into the common mycorrhizal network although they don't contribute to it. And they are still part of it and they're still joined to the other plants through that network.

27:46 So what effect does this root mingling of different plant species have on plant productivity, on immunity to pests and diseases, on tolerance to stress like droughts or water logging? As I mentioned before, here in Australia we've had massive droughts and now we're underwater and there's houses floating away and cattle floating away. But the things that live in the soil have to deal with all these stresses and these things come around in a cyclical nature. All around the world there's always various stresses, environmental stresses that plants have to deal with and microbes have to deal with as well.

28:27 So given that plants are in an environment that can be quite harsh at times, and given that we expect our plants to be productive, we want to be able to harvest them or we want to be able to graze them, it's very important to know what effect root mingling or the sharing of the sociobiome actually has on those functions.

28:53 So in this diagram here, I know it looks rather busy, and that's because I guess they're trying to put the plants a little bit in the background and bring the microbes to the foreground. On the left-hand side we have a bean plant and on the right-hand side we have a rice plant. So one is in the basic family and one is in the Poaceae family. And to get the maximum benefit from root mingling, we really want our plants to be in different families. So when I talk about putting different kinds of plants together, I mean plants that have got different functional traits or come from different plant families. So for example, if you wanted to put six different kinds of plants together, there's not a huge amount of benefit of putting six different grasses together. If you could put plants from six different plant families, then that's going to be much more beneficial.

29:52 So these days, when I'm not doing so many workshops and things, I don't get to use my voice a lot. So on the left-hand side we have our bean plant and you can see that there's a whole lot of microbes around the roots and they're obviously the rhizosphere microbiome. There's also microbes all over the plant on the leaves and the stems and the flowers and the fruits and they're the phylloplane microbiome. And then we have the endophytic microbiome, which is all the microbes that are actually inside the plant, the endophytes. And the more we look at these microbial interactions, the more we realize how important endophytes are. And most of the endophytes that are in the plant have actually come from the soil. So the plant has taken them up from the soil for some reason, for something that the plant needs. And quite often that could be to help the plant to deal with the nutritional stress of some kind or to deal with an environmental stress of some kind. It will take from the soil sociobiome, if you like, what it needs.

30:59 Now if we have different kinds of plants growing in close enough proximity for them to be able to share those microbes, what we will find is if there's different kinds of microbes under one kind of plant that aren't under the other or aren't in association with the other kind of plant, if they are able to mingle their roots or if they're able to be joined by a common mycorrhizal network, they're actually able to use the genetic material from another plant. So the microbes that are living in association with plants are able to, the genetic material that's in those microbes is able to be used by the plants for stress tolerance and also for the acquisition of nutrients. So plant productivity is very much influenced by diversity, by the biodiversity of the microbiome.

31:50 So if we have two plants, the same, for example two corn plants or two wheat plants growing side by side, they're going to have very similar microbiomes, in fact probably going to have identical microbiomes. And that's going to have a negative feedback effect on plant productivity. The microbiome is going to be able to detect that the microbiome that's next to it or near it is the same as itself and therefore it is a competitor. The microbiome is what will detect that this is competition. It's not the plant detecting that there's another plant it's competing with, it's the microbiome detecting there is another microbiome that it's competing with. And it basically won't cooperate, won't share resources.

32:43 If we have dissimilar microbiomes next to each other, so we have plants from different plant families next to each other and there are six or eight plant families that are quite commonly used in agriculture, there's no reason why you can't have six or eight families together that will have a positive feedback effect on plant productivity. And you'd wonder, well why, why would that be, that the microbiome when it detects that other microbiomes in its vicinity are dissimilar, why would it be that it will actually cooperate rather than refuse to cooperate? You know what, why does that cause that change? It's a change in behavior by the dissimilarity. The more dissimilar they are, the more they will cooperate. And this is because if we think of a diverse plant community, like a native prairie or something like that, where we have lots of different kinds of plants.

33:39 Plants growing together they will have different functional traits. In other words, they will respond to different environmental stimuli. Some may grow well when it's hot, some may grow well when it's cold. Some may prefer it when there's lots of soil moisture, others could be very drought tolerant. And that means that at some time of the year, almost any time of the year, there will be something that is able to grow.

34:04 If there is something in that plant community that is able to grow at most times of the year, and all the plants are connected underground by a common mycorrhizal network as well as other networks that's the one that we've most familiar with, but we now know that there's a lot of networking going on in the soil, then it means that there is energy coming into that microbial network continuously year round. If you only have one kind of plant, it's only going to grow productively at one time of the year or under one set of environmental conditions, and for the rest of the year the microbes in the soil basically starve.

34:42 So it is to the benefit of the soil microbial community to have as many different kinds of plants there as possible. And the microbial community at some level is able to detect that. And if the microbial community detects that there is a lot of difference between the plants, in other words the plants have dissimilar microbiomes, they're using dissimilar chemical messages, then the microbes cooperate and they have a positive feedback effect and they actually support each other. And this cooperation between the microbiomes, not between the plants, between the plants' microbiomes, actually has an effect on plant productivity.

35:37 I have mentioned this Yana biodiversity experiment many times before because it's probably the classic biodiversity experiment. It's run for at least 15 years in eastern Germany. And in this experiment they had four functional groups of plants: so they had grasses, legumes, tall herbs, and short herbs. So there's two different kinds of non-leguminous herbs. I think it's really important to get away from just grasses and legumes when we're looking at our mixes.

36:06 And they had one, two, four, eight, or sixteen different plant species. But remember that's four functional groups. So if they had sixteen plants, well let's say if they had eight plants, they didn't just have eight different grasses or eight different legumes. There was four functional groups in there, so there would have been two species from each of four functional groups. And I think it's the four functional groups, it's more important than the eight species. And they looked at biomass production and beneficial insects and microbial activity and water balance and carbon and nitrogen and phosphorus. And there's been hundreds of papers written out of this experiment.

36:38 But this is just an overview of the site. You'll notice that there's a river, the Yana River, just running around the back of this experimental area here. And I'll mention why that's important in a minute. But what they found is that when they had as the numbers of species went up in their experiments, they actually had a linear response in terms of plant biomass. So this is one species, two species, four, eight, or sixteen. And remember we've got four species they're from four different plant families. Where you've got eight, they're from four different functional groups, not just eight of the one kind of thing. And we've got this linear response. So the more diversity, the more functional diversity we have, the greater the biomass.

37:31 And that's going to be really important for a whole lot of reasons. Doesn't matter whether it's crop biomass or whether it's pasture biomass or even if you're just growing cover crop for soil protection or for feeding the soil microbiome. The more biomass you have, the more photosynthesis you're going to have, and the more that fungal energy channel is going to open. And in fact, it has been shown that there is a direct relationship between plant diversity and soil fungi. So forget all the stuff about fungal to bacterial ratios of one to one or whatever people talk about. You actually want them to be a lot more than one to one. And the way to open that fungal energy channel is through plant diversity.

38:18 So over here on the left we have just plants of two different functional groups, so it could be a grass and a legume for example. You will only ever be able to build soil towards certain depths with that limited amount of diversity. Over here where we have four functional groups and eight species, they're able to build. This community is able to build much deeper soil because these microbiomes are actually cooperating.

38:44 And this deeper soil proved to be very beneficial when that river did flood and the whole experiment went underwater. And it was sitting in water for several feet of water there. It was sitting in there for actually for several weeks. And the scientists thought that the entire experiment was going to be destroyed. But they found that the mixes that had the high diversity survived perfectly well the water logging, whereas the monocultures didn't. And the other side of that coin is that drought tolerance is much much higher where we have high diversity in terms of a lot of different functional groups. Again, your four functional groups.

39:32 So what happens when plants are in diverse communities is that they can respond to the drought by recruiting microbes from the microbiomes of dissimilar plants. This is where your dissimilarity becomes really really important in extremes of climatic extremes. This is where diversity really comes to the fore because, for example, in a drought situation you may have a plant, a species that of its own is not really very drought tolerant. But if it's growing next door to something that does have better drought tolerance, it's able to recruit microbes from beneath that other plant.

40:08 And when those microbes come as endophytes, they're taken up through the roots and they move into the plant, actually living inside the plants. So the plant has to feed them. So it means it has to photosynthesize more and produce more energy to actually like these have become borders or lodges, if you like, within the plant. And the plant is feeding those microbes. It's not going to do that unless it has a benefit from them being there. And those microbes will be able to bring about physiological changes within that plant that the plant's not able to bring about itself. For example, just produce enzymes or something that might thicken cell walls, reduce the amount of moisture that's lost through transpiration, and those kinds of benefits.

40:54 There's a lot of literature on this on how endophytes, beneficial endophytes, can actually provide drought tolerance to plants. So it's not a genetic thing, it's a microbial thing. And it comes again through diversity through the sharing of this rhizosphere microbiome. And we need to have root mingling for that to happen. So the higher productivity that we see in diverse plant communities is due to a

41:21 Whole lot of different factors. As Noah mentioned before, it's sort of like a jigsaw puzzle. We need to put all the different things together. You can't say it's just any one thing. For a start, we have lots of different families of plants and we're going to have variation in leaf architecture. Some things like the grasses, for example, are just going to have fairly narrow leaves sitting at say a 45 degree angle that really don't catch a lot of light. Other things like sunflowers, going to have big wide open leaves that do collect a lot of light. So this variation in leaf architecture results in more light interception and that means that photosynthesis is going to be proceeding at a higher rate. We have a higher photosynthetic capacity, which means there is going to be more carbon excluded into the soil.

42:09 More exudates means more microbes and more microbes is access to a larger gene pool. So when I say more microbes, I mean more different kinds of microbes because we have different kinds of plants. And then that's very important for our soil structure, for aggregate formation, because different kinds of bacteria and fungi and plant roots and plant root exudates and everything work together in a coordinated way to actually form aggregates.

42:36 Nitrogen fixing, which I'm going to talk about. I'm talking about free living nitrogen fixing and I'm going to talk about that in more detail in a couple of weeks time. Disease resistance, frost, drought and flood tolerance, all of these things come through microbial diversity, which in turn comes through plant community diversity. And these diverse systems are self-organizing. So the microbes actually know what to do and they know what to do because they have such complex signaling mechanisms that we're only just starting to figure out how this signaling works and how microbes produce these different signals, how they respond to them, how they know which ones to respond to.

43:32 Yes, it really is a very, very complex world under our feet, but it is a very, very well organized world. So just to give you one example of what I was saying, there's a whole lot of different levels of interaction. There's the interactions that are most commonly spoken about or that we've been aware of for the longest time have been the interactions between plants and microbes. We know that plants produce signals that stimulate various microbes and they stimulate microbes that they need for certain purposes.

44:10 Microbes also produce signals that can have either positive or negative effects on plants, so it can work both ways. And microbes also produce signals that can have positive or negative effects on other microbes. So we have all these levels of conversation going on. And I just wanted to give you one example. I think I may have mentioned this before in other webinars, but I haven't spoken about it recently, but it's the networking that goes on between trees in a forest, which is often attributed to the trees themselves, but has nothing to do with the trees really other than the fact that they're photosynthesizing. And it has everything to do with the common mycorrhizal network.

44:53 So this is one example here. We have a paper birch on the left hand side and a Douglas fir on the right hand side. The Douglas fir, you'd be more familiar with these trees than I am on these northern hemisphere trees, but the Douglas fir is going to remain evergreen. It's going to be able to photosynthesize at various levels throughout the year. Over on the left hand side, we have a paper birch which is going to lose its leaves in winter.

45:27 Now these trees are joined underground by a common mycorrhizal network and the fungal network in the soil is receiving all of its energy from photosynthesis. So in summertime when the paper birch has got leaves that capture a lot more light than the Douglas fir, most of the energy coming into the system is actually going to be from the paper birch. But the fungal network is channeling energy to, in this case, a seedling of a Douglas fir which is being shadowed by the paper birch in the summertime when it has leaves. So the seedling of the Douglas fir wouldn't be able to survive in the summertime because there wouldn't be enough light unless the fungal network kept it alive.

46:23 And this is often attributed to the tree actually being very benign and keeping another tree of another species alive, but it is the fungal network that is keeping a tree of another species alive. So why should the fungal network care whether a Douglas fir seedling survived or not? Well, it's going to care because in winter time, when the paper birch doesn't have any leaves and it's not photosynthesizing, the only energy that can come into that common mycorrhizal network is going to be from Douglas fir which is photosynthesizing over winter.

46:59 So it's a very simple example of just two species, but to show you the incredible power of the common mycorrhizal network and why the common mycorrhizal network actually behaves in that way because it is to the benefit of the microbes to keep as many different kinds of plants alive because that is going to ensure that there's going to be energy coming into the system for as many parts of the year as possible.

47:31 So when you ask the question who is directing traffic here, it is actually the microbes that are controlling what's going on, even though we look at those trees like absolutely huge trees. And the energy that's moving around in the soil under those trees is being directed by microbes. So that was really all I wanted to say about the soil sociobiome because the chemistry of it can get incredibly complex.

47:58 I guess if we look at things like insects, we probably see that this extraordinary chemical signaling going on between insects and plants and plants and insects and insects and other insects. I mean, isn't it amazing how pollinators can find they can go to a flower and then they can go back and tell others where the flower is and then they can all go find their way back even though it could be miles away? I mean, the signaling that we see in other ecosystems is just as extraordinary as the signaling that goes on in the soil, but we can understand it a bit better when it's something big that we can see.

48:38 And we understand that it's very complex, but it is also extremely well organized. So in the soil it is also very complex, but extremely well organized. And in the same way that insects and plants seem to be able to manage everything above ground, microbes and plants and there's also of course fauna in the soil, all our invertebrates in the soil, managed to get themselves organized and most of it is through some kind of biochemical signaling.

49:11 So that was all I really wanted to say. In technical terms, I'm happy to answer questions now. Not sure what I have to do. I think I have to stop sharing or do something. What have I done? Looks I can see you here just fine now. I'm going to use my privilege as the moderator and start off with a question that I have as far as I've heard the argument made as far as

49:43 Interseeding, which seems to be a hot topic over here, of people planting cover crops into their corn. I've heard the argument made that interseeding is maybe not the best idea because corn is still providing the most carbon. Carbon being the main factor there, but in what you're saying it really isn't so much about the carbon as much as the root types of having that cover crop in with the corn. Do you have any kind of thoughts on that? Would you argue against interseeding because carbon is more important than the soil biome?

50:26 So no, what you're saying is that there are a lot of exudates come out of corn roots. You're saying so that you could actually theoretically build soil faster. That really is going to depend on how the corn is grown because there's been some long-term studies that have been done in the United States. I think they're done at Illinois University. I'm not quite sure. They're called the Morrow Plots. I think the Morrow Plots are in Illinois. And those long-term studies were with corn but where nitrogen fertilizer had been used with corn, and I think that was something like 50 years or 70 years or some incredibly long time. The soil carbon levels had gone down.

51:06 Even though corn has the ability to produce a lot of root exudates, if it's grown with nitrogen fertilizer, that's not necessarily the case. You can still be losing soil organic matter. Soil organic carbon levels can be going down. So root exudates don't necessarily translate into stable soil carbon unless they are stabilized in the soil. And in order for the root exudates to be stabilized in the soil, they have to undergo microbial processing from lots of different types of microbes. And if you have a diverse plant community, you'll have all the different kinds of microbes that you need to actually stabilize that carbon.

51:47 It's all very well putting it there, like having exudation, but exudation doesn't necessarily translate to stability. So yes, diversity is very important. And I think you'll find that where people are interseeding corn, especially I think in the wide rows, I can see that that's gaining popularity, that you will definitely see much better improvements in soil structure, which is an indicator of soil carbon building. If you're getting more aggregate stability, then that's coming through carbon. It's carbon products that are actually the glues and gums that are sticking the soil particles together as soil carbon.

52:31 Okay, you could grow massive amounts of corn. Let's say you had irrigation and massive amounts of inputs. You could produce really high yielding corn and still have soil that's going backwards, which we know is why soil in many monoculture corn situations the soil is losing structure. It's becoming compacted over time. It's having all these soil degradation issues of a whole range of things.

53:03 Yeah, just because corn has the ability to exude a lot of carbon doesn't necessarily mean it builds soil, especially as a monoculture.

53:16 Okay, so I will open this up then to anybody else that has any questions. We have about 40 minutes here, so we've got plenty of time to get to those. Clay asks: What are the main challenges in pasture context to making use of the nutrients in the atmosphere? Above ground, is making use of atmospheric nutrients a goal worth pursuing?

53:41 I'm not really sure what you mean by atmospheric nutrients because the only, well, if you consider carbon to be a nutrient, it's a trace gas, 0.04 percent. Obviously that's a trace gas that we want to get into the soil. So photosynthesis is going to be absolutely key to that. So with pasture, if you're talking about pastured livestock, definitely you want your four functional groups in your pastures. You want to really be looking at your non-leguminous herbs in there as many of those as possible.

54:14 The only other element in the atmosphere that would be important would be nitrogen, obviously. 78 percent of the atmosphere is nitrogen. And you'd also be wanting to try to get as much nitrogen into the soil as possible. And that's going to come through maximizing or optimizing photosynthesis because the more root exudates you have, the more free-living nitrogen-fixing microbes are going to be activated through photosynthetic capacity and through root exudates. But I can't think of any other nutrients that would be in the air other than carbon and nitrogen.

54:53 Okay, this was in reference earlier you were talking about fungicides. So Jacob asked: Were you referring to fungicides both foliar applied and seed applied? Especially seed applied is obviously the most detrimental because we want a newly emerging seedling to be forming relationships with microbes. And we really want it to be pumping out exudates like a seed will start to feed microbes in the soil even before it's produced any leaves.

55:21 But foliar fungicides are also detrimental. And when all the research shows that the most detrimental chemical to the soil microbiome, fungicides are the most detrimental chemicals, plural. And if you have a sufficiently diverse soil microbiome, you actually won't need fungicides. When plants are attacked by fungi, it's a symptom. It's a symptom of lack of diversity in the soil microbiome. If a plant would be able to protect itself or it would be able to take up microbes that would help it to protect itself if it had access to those microbes. So it's really all about stimulating the soil microbiome rather than using a fungicide.

56:13 Okay, can you recommend any key research papers that would address the idea that the soil food web is incomplete or insufficient? Absolutely, I can. And I can send them to you, Noah, and then people can access them from you. There's been a whole series of it. It's mostly been undertaken in the UK. In fact, there's a whole book, I think. But there's certainly been some of those, you know, what's like a big review. A review will come out where there may be say, I think the one I was looking at last night, there was 12 chapters in it. And each chapter was written by somebody who was an expert in their field about their view of the soil food web and how the soil food web works.

57:03 And all of the 12 chapters in this review were looking at the fungal energy channel and the labile carbon inputs. And all of them have used terms like soil food web re-visioned or soil food web challenged or classic soil food web obsolete or whatever. So the classic soil food web, which unfortunately is still promoted in a lot of literature today, has been shown to not function as it was thought to or to function in a very minor way. I mean, yes, protozoa do consume bacteria and yes they do release some nitrogen in that process. But that's not the principal pathway in soil.

57:54 Okay, Steven asks—oh, go ahead. Yeah, I'll send them to you. Yeah, I mean not now. I can't do that, but I'll send it to you at the end of this.

58:05 Okay, that'll be perfect. And if anybody wants, if anybody wants that, I can email it to them. My email is Noah.

1:06:27 Because it won't ever reach a quorum because your body will prevent it from doing that. It's only when it actually reaches a quorum that it has an effect.

1:06:37 So it's detrimental or so pathogens, if you like, have to reach a quorum in order to express their pathogenicity or their virulence. And beneficial microbes have to reach a quorum in order to be able to express their beneficial effects that have a beneficial influence. So yes, quorum sensing is very important in all microbial communities in all habitats and for all kinds of microbes.

1:07:07 Larry says, what are some primary research gaps within regenerative agriculture that would lead to outcomes that would benefit producers? Off the top of my head, I couldn't really say. I think the biggest issue for people is actually moving away from high analysis fertilizers.

1:07:37 I think there's just this huge fear of the wheels are going to fall off if we stop using nitrogen, for example, seems to be the classic. In the United States, and here in Australia, the big fear for our farmers is actually phosphorus. If we stop using phosphorus because our soils are so very old and deeply weathered that the phosphorus is tied up, it's locked up with iron and other elements in the soil and plants have difficulty obtaining it. And people worry that if they don't use phosphorus that nothing will grow.

1:08:12 In the United States, the big issue seems to be nitrogen, which we are going to talk about. I think that's the biggest, well from my perspective anyway, just off the top of my head, is actually getting, helping people to transition away from using those kinds of products because they are definitely going to interfere with all that biochemical signaling that I was talking about that takes place in the sociobiome.

1:08:34 All those different kinds of microbes and all those, they talk about different trophic levels, there's different energy channels in the soil and different trophic levels. They all need to function as a whole. Everything needs to be interconnected and those signals need to get through. They need to be produced, they need to be responded to, they need to be received and responded to, and that can't happen if we're using high analysis fertilizers. We just throw the whole thing out. All those channels just become totally disrupted. All those channels of communication break down when we use either insecticides or fungicides or high analysis fertilizers. We interfere with that very intricate signaling that's going on in the soil.

1:09:22 And I think the biggest fear that producers have is of moving away from something that they know works, even if it results in dysfunctional soil. At least they still get a crop.

1:09:38 Yeah, and like you said, you will be addressing the phosphorus and nitrogen in the weeks to come. So like Gene asks, is there a fungi that can fix atmospheric nitrogen? I believe those are things that we'll be getting into in future webinars. So any questions, I think on that we can probably touch on. Well, I can't answer that one today. No, there is not a fungi that can fix atmospheric nitrogen, as only bacteria and archaea are the only microbes that can fix atmospheric nitrogen. But there are hundreds of species of those that can fix the atmospheric nitrogen.

1:10:20 Can you repeat again what you said about genetic material from microbes being utilized by plants? How does the genetic material of the microbe actually benefit the plant?

1:10:31 Okay, so what I mean is that it would be genetic material that the plant itself wouldn't possess. So the plant, I think drought tolerance is probably a classic example, and there's lots of science on that as well. If you want me to send you one of those or a couple of those articles, people can read them for themselves. For example, we have a plant in a situation where it's suffering from a moisture deficit. It's not able to tolerate that level of moisture deficit, so it's probably going to die. But if it has the ability to take microbes up from the soil that have the ability to influence physiological processes within the plant that would help it to utilize moisture more effectively, for example, there could be plants that can take up microbes that cause cell wall thickening, right? Cell wall thickening that within the plant wouldn't normally take place. It's because of some enzymes that the microbes are producing or some effect that the microbe is able to have on physiological processes within the plant.

1:11:47 And the plant is selective. Going to selectively take that microbe up from the soil only if it needs it. So if there's plenty of moisture, the plant will not have that microbe in its system. In a moisture deficit situation, the plant will signal to the microbe and will, what's the word for it? The plant will internalize those microbes. It will signal to those microbes and attract them around the roots, and when the microbes are really close to the roots, they can be internalized at the root tips. They can be taken into the plant as endophytes. Obviously the microbe is cooperating in that. It wouldn't allow the plant to take it up unless it was cooperative behavior. When it's inside the plant, it's going to be fed and housed by the plant basically. So all its nutritional needs are going to be provided by the plant. And in return for that, the plant's going to expect something from the microbe. And what the microbe can do for the plant is change its physiology so that it is now more drought tolerant or more tolerant of the moisture deficit. Then if moisture was supplied and the plant no longer needed that microbe, it may stop supporting it. And it's not going to be present anymore.

1:13:03 So you could analyze a certain species of plant in a situation where it wasn't suffering from moisture stress, and you would find that that particular microbe would not be in the plant. Then you subject the plant to moisture stress, and you find that that microbe that changes the plant's physiology is inside the plant. And it's taken it up from the soil. It's a microbe that normally lives in the soil. So what I mean by the genetic material is that the genes that the microbe possesses that enable it to, because microbes can switch genes on and off in plants as well as they can switch genes on and off in people. Microbes are very powerful, and the plant in a natural situation needs to be able to interact with the microbes in the soil to assist it in situations like that.

1:13:58 But there is plenty of literature on that, and I was just going to add that to my list here. I'll send you something, and then you can just, if you want, put those links up with the video or something. People can read more about it, like how it actually works.

1:14:14 It sounds like you need to just write a book. Ah, yeah, right. The problem is the book would be a different book every year because there's just so much information coming out that, I mean not that the information wouldn't be right, but what we wrote last year we'd know a lot more this year. Next year we'll know more again.

1:14:35 Yeah, and the number of cycles that are coming out on the soil microbiome are just incredible. I know the same thing with our.

1:14:44 Resource guide that comes out every year, and it seems like we're always saying we got to keep it the same length, but there's always just new information that comes out and it's like, well let's just add four, four pages and that turns to eight, and we try to make as much space for you as we can.

1:15:01 Annette asks if your soil is compacted, how would you aerate it to get the microbes thriving again? Yeah, again it's going to depend on the situation. Is it a cropping situation, a pasture situation, is that somewhere arable? I mean people will use soil aerators as a like a short-term, quick start way of getting air into soil. I mean obviously you need plant root exudates and you need microbial communities to rebuild aggregates, but the plants have got to be able to grow. And if the soil is really compacted, you just won't be able to get plants established in there. So I don't have problems with soil disturbance if it's a one-off thing. You're doing something to actually get you have to create an environment that plants can grow in in order for plants to be able to synthesize and produce exudates. And you can't expect them to grow in something that's like concrete.

1:16:02 The issue I have with soil disturbance is that someone will say okay my soil's like concrete, I'm going to go in and I'm going to rip it up and power harrow it and everything, and then if they've done nothing about plant cover, keeping the soil covered and having diverse covers, then it's just going to go back to being compacted again and then I want to come in and rip it all up again. So there's nothing wrong with doing that as a one-off and using it as a way to get good plant establishment and then for your root exudates to come in and do the work after that.

1:16:42 Robin says they have very mineralized soil. Robin says can you address whether that is a good thing or a bad thing and how I can address it if it's an issue? That's a term I never heard until I went to the United States, and I think mineralized soil means it doesn't have any organic matter left in it. In other words, it's just a whole stack of soil minerals. I think that's what he means. Soil minerals, basically that's just dirt, and it's not really fertile topsoil until we add organic matter or organic carbon, and that's going to come through plant root exudates. So if what he means by mineralized soil is soil that only has been, I mean that's what soil is made from, it's all made from minerals. But in order to have functional, high functioning soil, we want to have a whole lot of life in it as well as the minerals, and that life is going to come, can only come from plants really—plants and their exudates and all the microbial communities that those exudates support. So I'm not exactly sure of that question, but if he's been told he has mineralized soil, I think what he's been told is it's dysfunctional. It just is just a whole pile of minerals and it doesn't have any life in it.

1:18:17 Nisha says if you had a magic wand and could do one thing to stop climate change what would that be? I can't think of the name for that. There's a big ocean current that circulates around the world. Some people call it the Atlantic Conveyor, but it does have a more a scientific name than that. But the Atlantic Conveyor is another word for it. And it moves, actually I think the Gulf Stream that comes up the east coast of the United States is part of the Atlantic Conveyor. And sort of brings warm moist, obviously it's an ocean current, yes it is, but warm water up the east coast of the states, and then at some point in the north it takes a deep dive and goes down and sort of goes around. The Atlantic Conveyor is the chief determinant of global temperatures. So and there is evidence to suggest that that's actually slowing down, and at some point that will stall and will reverse so that all the cold water will well up and come in the other direction, so down the east coast of the United States, for example, instead of having warm water coming up from the south, you're going to have incredibly cold water coming down from the north, and that will generate an ice age. Who knows whether that's going to be in 100 years or a thousand years or ten thousand years. But the chief determinant of global temperatures is the direction of that major ocean circulation current. So there's nothing I could do to change that. It's going to change all by itself.

1:20:08 We have two questions in regards to getting off synthetic fertilizer in regards to adding either bio fertilizers, the anaerobic was brought up as well. Do you have any thoughts on adding to your soil to get away from chemical fertilization? There is no doubt that you can stimulate the soil. I don't, there's in my mind there's a lot of difference between a biostimulant and a biofertilizer. To me, and everyone defines this differently, but to me a biofertilizer is something that you would use in place of a synthetic fertilizer. So you might use something like fish hydrolysate or a compost or something like that in place of using a synthetic fertilizer. I would call that a biofertilizer. A biostimulant would be something that you would use to actually stimulate the microbes that are in the soil that are not active. So as I said, the majority of microbes in the soil are in a dormant state, and so one of the secrets, I guess, to the soil sociobiome is actually to activate those dormant soil microbes. And one way that we can do that is by using a biostimulant, and the best place to would have put a biostimulant is on a plant seed before you plant it.

1:21:37 What would a biostimulant entail? A biostimulant will be some product that actually has a whole lot of those signaling molecules in it that I talked about that microbes use to communicate with each other. So if the biostimulant was worm leachate, for example, or vermi liquid or whatever word you want to use to describe that, it will be something that it has passed through the gut of an earthworm so it comes through a fermented or fermentative anaerobic environment that's absolutely chock block with a huge diversity of very active microbes. So there's going to be a lot of chemical signaling molecules in that product. So what it means is that you're going to be applying the chemical signaling molecules that microbes use to communicate with each other. You're going to put those onto a plant seed, so as that seed is germinating, it is going to detect those signals because the only way that plants and microbes know what's going on in the soil is through chemical signaling. And it's going to detect those signals and interpret them to mean that it's in a very rich microbial environment, so it is going to respond by producing a lot more exudates to feed the microbes that its senses are there, even though the microbes aren't there, because any microbes that you put into the soil are immediately going to be consumed by residents or microbes. They're probably going to live for seconds, not even minutes. So if you put these microbial signaling molecules onto the seed.

1:23:21 The plant will respond and feed them, so it's going to produce more exudates. And then when it produces more exudates, it is actually going to feed residents or microbes that are going to respond in turn. And so you just set off a whole positive chain reaction of more microbes, means a healthier plant can in turn photosynthesize more, can in turn produce more exudates. Sort of plant intelligence and microbial intelligence and the whole interaction between those two things is stimulated by a biostimulant.

1:23:54 A biostimulant could be something that you could make on farm yourself. It could be something through Korean natural farming or it could be bokashi or it could be fermented compost, or you could have a worm farm or there's so many different ways that people can make biostimulants. But if it's a fermented environment that it was created in, then the abundance of microbes is going to be much higher than in an aerobic environment. So the density of microbial chemical, the chemical signaling molecules that you're applying is actually going to be higher. You're going to get more chemical signaling molecules from a fermented environment.

1:24:42 In regards to interceding cash crops and companion crops, is it best to do it in the same seed row or separate seed rows? This is in regards to what you mentioned with root mingling and stress tolerances. How close do those need to be and do you have any kind of thoughts on how you would plant interceding?

1:25:04 Again, that depends a lot on what the crops are and what equipment people have. I know Derek Axton is, well, last time I was speaking to him, he has sort of experimented with a whole range of either having plants in the same row or having them in separate rows. And for his purposes, he's found he's actually better off having the rows side by side. That's worked better for him. And because, as long as the plants are within a reasonable distance of each other, their roots are still going to mingle. They don't have to be in the same row. And they're going to be also joined by a common mycorrhizal network if at least one of the plants that is in there is mycorrhizal. If one of the species is mycorrhizal, then the whole field is going to become mycorrhizal.

1:25:56 In some situations, for example, our corn growers in the northern part of Australia—it's a hot part, and the southern part is down near Antarctica, that's a cold part—so we grow things like corn in the northern part. They have found that if they plant soybeans in with their corn, that they don't need to use nitrogen fertilizer. They get exactly the same yield by putting soybean in as they do by not using nitrogen fertilizer. And they've found that the soybeans actually work best in the row with the corn, so they're planted in the same row with the corn because they don't care whether the soybeans grow very much at all. All they really want is for the soybeans to have their root exudates to be mingling with corn root exudates.

1:26:39 So in that particular situation, they've found that having soybeans and corn in separate rows doesn't work as well as having the soybeans in the row with the corn. And in that situation, it was just a matter of throwing all the seed in together. Made it really easy. You didn't have to have specialized equipment or anything for doing that. So it's going to depend on the species. It's going to depend on your equipment and it's probably going to depend on whether you intend to harvest both of the crops or sometimes even more than two crops. You know, sometimes in polycrops, people are actually harvesting the crops separately and separating, or harvesting them together and then separating the seed. All those kinds of things, or you could even have your example of like relay cropping where you're going to harvest both of them but at various separate times, give different times of the year. You're going to harvest one thing to a totally different time of the year to the other. So it's a very complex situation. And that's a very rapidly evolving field that I think is the way the future of farming is definitely poly cropping with a whole lot of different variations on that theme. And we're seeing good examples of companion crops, companion cropping, even where you're still going to have your one cash crop. You're going to discard basically all of the other seeds, but your cash crop is actually growing better and yielding higher when it's got companions in with it. And that's just all planted in together. It's not in separate rows. Just all seeded in together.

1:28:14 Okay, and I want to be respectful of your time here so we don't go too long. Do you have time for a few more questions or do you need a heads up?

1:28:20 Yeah, I wasn't looking at the time, but that's fine. I'll get to a couple more and then we'll let you get out to your garden because we don't want to stop you from doing any of that.

1:28:35 Claire says that you elaborated, or can you elaborate on the fungal bacteria ratios not being so important? That was something that you mentioned. People often are worried about, but can you speak to that a little bit on why you don't think it's so important?

1:28:51 No, I actually do think it's incredibly important. But I think it's really important that there be more fungi than bacteria. Because in our healthy soil, where we're seeing where people are getting really good results, when they do a biomass on the fungi bacteria, they find they have more fungi than bacteria. I mean, the problem with the classic food web model is that for some strange reason, people are trying to keep that ratio at one to one. I've never really like there's been a theory out there that arable crops and pastures are going to function better if that ratio is one to one, and if for some reason it goes over, so you have like say two to one—in other words, twice, if the fungal biomass is double the bacterial biomass—people get concerned about it and start putting bacterial foods out like molasses and things, trying to increase the number of bacteria in soil. You want to get your fungal to bacterial ratio as high as you possibly can. Don't try and keep it at one to one. That's what I'm saying. I mean, I know a lot of them are less than one to one. Lots of there's plenty of situations where the fungal to bacterial ratio might be point three to one or something—in other words, fungi point three and to every one bacteria. That's woeful. When you, but you want to get it right over one to one. You don't want to hold it at one to one. You want it to be two to one or three to one or you know, even higher, as high as you can get it. Because those fungi are going to be your fungal energy channel. That's the pathway that's bringing energy into the whole soil ecosystem and feeding all your other microbial groups is through that fungal energy channel. So you have to just put out of your mind all that classic soil food web stuff because it doesn't work. Empirical studies, you know, the science actually shows that that model is outdated, but people still are clinging to that and thinking that they have this one-to-one ratio.

1:30:48 So this is kind of along the same lines of that ratio, but Steven says that he has a new pasture that's producing well under regenerative grazing, but it's developing more and more rose bushes.

1:31:01 Is that because of a higher fungal soil and does he need to worry about rebalancing his bacteria to fungi ratio?

1:31:10 Yeah, I can't answer that question. I don't know whether that's the reason, but I do know that last year I was doing some work in Namibia, which is a country in Africa, and they have about 60 million hectares, which I don't know what that is in acres but just double it, let's say 120 million acres, a little bit close enough, of degraded rangelands that has been encroached by shrubs or bushes. They call it bush encroachment in Australia. We call it shrub encroachment, but you would have to see the same thing in parts of the United States where you had things like creosote and those kinds of shrubs or bushes come into what originally was, if you went back 100 years or so, were perennial grasslands. Had been encroached by woody species. Let me just put it that way. Same thing has happened in Australia. Same things happen in many parts of Africa.

1:32:08 And these people in Namibia were thinking that the reason they had bush encroachment was because their stores were fungally dominant. I said, have you ever measured the fungal to bacterial ratio? And they said no, but we've just read in the literature that everyone's talking about fungal dominance will create bush encroachment. And I said, well, it's your grazing management that's created the bush encroachment because all their good perennials have been grazed out of the system. And then the only thing that can grow there now are these deep-rooted shrubs. So it's, you know, this hang-up that we have about fungal to bacterial ratios has caused people to go down the wrong track, not look at the actual management issues that are creating the problem. And changing, trying to, I mean, I don't know how you can ever change fungal to bacterial ratios anyway, other than all people will put bacterial foods out and encourage bacteria to try and get a one-to-one ratio. But encouraging it, they are going to encourage all the wrong kinds of bacteria in their soils and probably lead to more soil compaction.

1:33:20 Yeah, it's the wrong model. It doesn't work, and it's not a cause of woody weed encroachment. Let me put it that way. There's something else that's causing that. If you want to call the rose bushes, they are obviously an invasive woody shrub. It's not due to fungal to bacteria ratios. No, something else is causing it.

1:33:41 Okay, so fungi network increases through diversity of plantings and you have a healthy microbiome. Do you see nutrient densities in plants also increasing?

1:33:50 Yes. That's what I was hoping you'd say. That was the main reason you'd be doing that. Well, because at the end of the day, at some point in time we want our producers to be rewarded for producing nutrient-dense food because that will act as incentive to improve the soil microbiome and we'll also improve human health, obviously. That should be a great thing.

1:34:23 Where do all the fungal species come from once you have a diverse cover crop? Is there ever a need to apply microbiology through compost, compost tea? And I'm going to kind of add on to that because we get this question a lot of how long do I need to be applying inoculants or compost teas if I'm in a perennial system or if I'm continuous cover crops?

1:34:51 So in your experience, how long do you need to be applying these things? Again, it depends really. There's a lot of confusion about compost teas, compost extracts, if it's a brewed tea, and if people think they're applying microbes, I can tell you those microbes do not survive when you apply them to the soil if you're just spraying them out on pasture or spraying them out on soil. They're going to be consumed as just a food source that's going to be consumed by the soil microbiome. So I can't really answer that question. I think a biostimulant on a seed, if you're planting crops, a biostimulant on the seed is really beneficial because it really does kick-start that whole conversation basically between the plant and the resident soil microbes. A biostimulant by that I mean you're putting the chemical signature of compost or the chemical signature of very liquid or something. You're just using those chemical biochemical signaling molecules. In terms of spraying things out on pastures again, biostimulants yes, brewed products maybe not so much.

1:36:02 There was a question here I just gotta find it about, yes, you talked about plant exudates being the main channel for the transfer of carbon compounds to the soil. One of the things that we're told here in regenerative ag is that you must integrate livestock or manure. Can you do that without livestock and still increase soil carbon? Is the plant exudates enough, or do you have to have the livestock component?

1:36:30 No, yes, plant exudates are definitely enough. We're seeing huge improvements in soils with companion planting and multi-species covers in cropping areas where there are no livestock. Definitely, yes. Diversity is the key there.

1:36:54 Okay, well with that I think we'll wrap up. I know that we have some questions that we did not get to, so I apologize for that. The good news is we have Christine back with us next week and the following two weeks after that. I did keep a record of all these questions, so we'll see if we can get those answered later on. But if there's something really pressing that you want to get to this week, feel free to send me an email. My email is noah@greencoverseed.com, and I will get those answered. Well, I probably won't answer them, but I'll make sure that someone smarter than me gets them answered, and we'll get that over to you.

1:37:32 Thank you so much for your time this evening. I appreciate you coming on and sharing with us. Thank you to the audience for all your questions. It was great dialogue, and we look forward to seeing everybody next week. Christine, do you have any final thoughts?

1:37:48 I was actually thinking about my garden. No, we're sorry, because it was just coming up to just after 11am in the morning here. I was just looking at the window. The sun shining now, stop raining. It's the perfect garden time. Well, we'll let you go, but thank you so much for sacrificing your time with us this morning. That's right, but I'm going to send you a couple of links like to the soil food web information, to the functional diversity like how do you measure functional diversity, and also to how do plants access genetic material from the soil microbial pool to assist with drought tolerance and those kinds of things. So I've just written myself a list, and as you said, if any other questions come up, we can, we've got other sessions that we can deal with those or I can send you further information for those. So until next time, I'll go out and get some functional diversity happening in my vegetable garden.

1:38:45 That's right. Practice what you preach. Well, and I'll let you guys know next week is going to be the phosphorus paradox, and we actually had Christine on, was it November, to do that? And so we recorded it. What we're going to do is just, it'll be a replay of that webinar that we did, but she has been generous and kind enough to sacrifice her time to come on and answer some questions. That was obviously the reason we wanted to do this series. So she'll be coming on live if you guys want to ask your questions there as well next week. It'll be the same time at 5:30. Thanks again, and we'll see you all next week.