How Plant Diversity Replaces Nitrogen Fertilizer

0:06 We are live on Facebook. I think so I'll give people about 30 more seconds just to start logging in and we'll go ahead and get started.

0:39 Okay we're good to go here. Thank you everybody for tuning in this week. This is week three of our webinar series we have one last session here next week on April 20th so we are at the halfway mark but we have plenty of good information left. In fact some of the best is yet to come. So I'm looking forward to this talk it's one that I've heard a couple different times but there's always a bunch of questions that I have afterwards so I'm really looking forward to the Q&A on this one particularly.

1:14 If you have questions during the webinar you can either put them in the Q&A or in the chat box that way we can record those questions and I can pass them on to Christine later. If we're not able to get to those we're going to let Dr. Jones go until about 6:30 and then open it up to your questions so in the meantime everybody is going to be muted.

1:40 To kick us off Keith do you want to go ahead and introduce Christine for the third time?

1:44 Sure yeah thanks Noah. For those of you that are joining us for the first time welcome and for those of you that are joining us as a repeat watcher thank you for coming back. Again our guest is Dr. Christine Jones one of the world's preeminent soil microbiologists from Australia. Christine has been a frequent speaker in the United States so I would say over the last four or five years especially.

2:14 And Christine I don't know exactly what made you famous over here but for me what really put you on my radar and why we really were excited about getting you to write for our soil health resource guide it's this topic right here. Your article that you had on your website entitled 'Nitrogen: The Double-Edged Sword' was just really a game changer for myself and lots of other people. That's one of the first talks that I heard you give over here in the states and really before I had ever met you or ever knew you.

2:50 And so your thoughts on this concept of nitrogen to me is just it's some of your best work I think and it's certainly some of your most widely known work. So I'm really excited to have the have our folks who are tuned in here the ones who will be the many thousands who will be watching this on our YouTube channel later on. It's a great topic so pay close attention ask lots of questions we're in for a great ride.

3:19 Dr. Jones I turn it over to you.

3:22 Thank you very much Keith for that fantastic introduction and thank you very much Noah for your great introduction as well. And it's always honestly just an enormous pleasure to be part of the Green Colouring team and have this opportunity to talk about one of my favorite topics which is nitrogen. So if I can we're going to have a perfect day today where everything is going to go absolutely flawless.

3:58 Now so what you can see in front of you there is a dinitrogen molecule in other words two atoms of nitrogen bound together by a triple bond and this is the form that nitrogen occurs in in the earth's atmosphere. Last week we talked about phosphorus fertilizer and the points that I made about phosphorus is that it's relatively immobile in the soil. In other words wherever you put it that's pretty much where it stays.

4:40 Only about 10 to 15 percent of the phosphorus fertilizer that is supplied is taken up by plants in the year of application which means that 85 to 90 percent of our fertilizer additions are immobilized. In other words they're fixed in the soil. Bound phosphate has a negative charge it's highly reactive and it is going to bind with elements in the soil that have a positive charge such as iron and aluminum. And in alkaline soils with calcium.

5:14 And even though a lot of the phosphorus that farmers have added to their soils has not been taken up by plants provided they haven't lost the soil through erosion they have now actually formed a large phosphorus bank. And that phosphorus is going to be able to be accessed at some later stage using microbial intermediaries and we'll talk about how we're going to activate the soil microbiome. So you haven't actually lost that unless you have lost the soil and if you've been using phosphorus fertilizer the good news is that most of it is still there and you can access it later.

5:54 The news with nitrogen is not so good. Nitrogen fertilizers, I'm talking about inorganic forms of nitrogen now like nitrate and ammonium, it's highly mobile in soil it doesn't actually bind to soil particles and stay there. Only about 10 to 40 percent of the nitrogen that's applied as fertilizer is taken up by plants usually because they're just not able to take up such massive amounts of nitrogen particularly if it's applied like pre-plant.

6:24 In fact sometimes in Australian situations we've seen when quite a lot of nitrogen has been like pre-loaded sometimes like say six weeks before a crop is planted and we go and measure the soil the day that the crops being planted and none of the nitrogen that was pre-loaded is there it's all gone by the time the crop is even planted. And then of course the seedlings come up in their nitrogen diffusion.

6:46 But even under ideal conditions somewhere between 10 to 40 percent is taken up by plants the other 60 to 90 percent goes somewhere else into the water up into the air and it's going to cause a problem. It's a very significant environmental pollutant all around the world and nitrogen is very rapidly transformed. It occurs in several different chemical formations and it can move from one of those to another one very very quickly.

7:18 And it does not the nitrogen fertilizer that you apply to your soil does not accumulate and form a nitrogen bank like a phosphorus fertilizer does. In fact the more fertilizer nitrogen you use as a general rule the less nitrogen you have in your soils.

7:39 Now if we're looking at this in terms of energy use efficiency and fossil fuel use all those kinds of things the production of nitrogen fertilizer has a is a very highly energy demanding process and it uses six times more energy like per tonne of fertilizer than the production of phosphorus fertilizer. And producing nitrogen fertilizer also emits large amounts of methane which is another greenhouse gas. So if it is possible for anything to be more detrimental than phosphorus fertilizer then nitrogen fertilizer is it.

8:17 So why do we use it? Well Keith in his introduction to last week's webinar on the phosphorus paradox said we're never going to run out of nitrogen and that is just so true. But 78 percent of the atmosphere is dinitrogen which is that molecule that I showed right at the beginning, two nitrogen atoms joined covalently joined with a triple bond. That means in metric terms that we have 78,000

8:50 Tons of nitrogen gas sitting above every hectare of land. And I do the math on that, that equates to 70 million pounds per acre. So we have 70 million pounds of dinitrogen gas sitting above every acre of land. There is really no need to go out and buy it, especially when we see all the downsides of using inorganic nitrogen fertilizer. But the problem is that all of that nitrogen that's in the atmosphere, that giant nitrogen, is relatively inert and it's not directly available to plants.

9:30 Sometimes you'll hear people say legumes, for example, can fix nitrogen. Well, legumes can't fix nitrogen. Legumes can form a symbiotic relationship with rhizobia bacteria that can fix nitrogen. So it's always going to be a microbe that's in association with the plant, not the plant itself. And so as with phosphorus, as we discussed last week, it's going to be microbes and their enzymes. It's going to be microbial enzymes that are going to be the key to accessing nitrogen.

10:06 In this case, the microbes are called diazotrophs. The diazotrophs are bacteria and archaea that are able to break that triple bond between two nitrogen atoms and actually convert that relatively inert dinitrogen—which is why they're called diazotrophs—into a plant-available form. But the trick here is that diazotrophs utilize the enzyme that they use is called nitrogenase. There are a whole range of nitrogenases, sometimes they're called dinitrogenase, and sometimes they're called nitrogenase reductase, but basically it's a group of enzymes called nitrogenases. That is the enzyme that breaks that bond in the inert dinitrogen gas.

10:58 Nitrogenase, the enzyme that microbes use, is inhibited by oxygen. So the only place in the soil or in a plant where diazotrophs are able to break that triple bond and convert inert dinitrogen gas into nitrogen in a plant-available form is in specialized what we call microaerobic fixation sites. In other words, microaerobic means there is a little bit of oxygen there, but not a lot. It's not anoxic and it's not anaerobic, but it's not aerobic either. It's a low partial pressure of oxygen. And these specialized fixation sites are inside root sheaths and inside water-stable aggregates.

11:51 So if we want to know whether our plant community or our soils are able to fix nitrogen or able to support free-living nitrogen-fixing bacteria and archaea, we just need to look to see whether the plants have root sheaths or whether water-stable aggregates are forming in that soil. And if you are building topsoil, if you have evidence when you go out with a spade and dig a hole, like visual soil assessment is going to tell you a lot more than sending a sample to a lab. You need to look to see are these things happening in my soil? Do my plants have root sheaths? Is whatever it is that I'm doing, is it forming water-stable aggregates in this soil? Can I see evidence of aggregation? And if you can, if soil building is taking place, then nitrogen fixing is taking place, because as I explained last week, the humic molecules that are involved in that whole soil-building process are a combination of carbon and nitrogen—carbon and nitrogen in the same molecule. So you know that nitrogen fixing is happening if you're building soils, and that's probably all you really need to know, because that will certainly tell you more than a lab test will tell you.

13:06 The bad news is that the formation of root sheaths on our plants and the formation of water-stable aggregates is inhibited by the use of high-analysis inorganic nitrogen fertilizer. So what do I mean by inorganic nitrogen fertilizer? I'm talking about things like nitrates, ammonium products like anhydrous ammonia, or urea or nitram. Now, anything that's got any form of nitrate or ammonium in it is going to be an inorganic nitrogen fertilizer. And if a lot of that is applied—and I'll talk about at the end of this presentation, I'll talk about what I mean by a lot, because in actual fact a little bit can be stimulatory. It's one of those things where the concentration effect is very important. But if people are using high amounts, and I mean if you're using anything over 50 pounds per acre, it's too much, and it is actually going to inhibit root sheath formation and the formation of water-stable aggregates.

14:09 So then natural, free-living nitrogen fixing can't happen. So in other words, the more we use nitrogen fertilizer, the more we lose it. And there's plenty of research evidence around that. And the unfortunate thing about the research is that there have been millions of dollars of money go into research into nitrogen dynamics in agricultural soils every year. There's probably millions of dollars spent, and every year farmers around the world spend over 100 billion dollars on nitrogen fertilizers. And all this research and all this money that's spent on fertilizers is mostly under conditions that are not supporting activities of free-living nitrogen-fixing bacteria and archaea. So if you're reading a paper about nitrogen dynamics in agricultural soils, well, for a start, if synthetic or high-analysis inorganic nitrogen fertilizer has been applied, then what you're looking at is irrelevant to a situation that's going to be supportive for free-living nitrogen-fixing bacteria.

15:19 If the research was conducted in soils that have been kept in storage for a long time and they're not biologically active, the results of that research are going to be virtually meaningless. If the research has been conducted in a monoculture, the results of that research are going to be virtually meaningless. In other words, we can probably discard about 99.9 percent of the research that's ever been undertaken into nitrogen dynamics in agricultural soils. So we have to go back to ground zero and start again, and look at this with a totally like we need to start with a blank canvas and figure out what is actually going on in our soils.

16:04 Now, I showed this photograph last week or the week before, but it's about this—is what a lot of scientists will see when they're studying plants in the glass house or in the laboratory. They'll see plants that have clean white roots like that, which means that they're not looking at plants in a situation that is going to support free-living nitrogen-fixing bacteria and archaea, because there is nowhere in that environment for nitrogenase, the enzyme that is going to convert atmospheric nitrogen into a plant-available form. There is nowhere in that environment for nitrogenase to be able to function, remember it's inhibited by oxygen. So if we have clean white roots like that with no root sheaths, there is not going to be any nitrogenase active. So here are some photographs taken in the field. This is a fence-line comparison. On one side, on the left-hand side, we have a farmer that

17:05 Has been using a nitrogenous fertilizer under an oat crop and on the right hand side we have the same soil, the same crop planted at the same time, everything the same where they have not used any nitrogen fertilizer. And you can see the difference. On one side we have bare roots. It's going to be lots of oxygen around those roots and it's not possible for free living nitrogen fixing bacteria to help that crop.

17:30 On the right hand side we have the formation of aggregates around the roots. You'll also notice there's fungal hyphae in that photo and fungi are very important. They're plant associated fungi. They're supported through that fungal energy channel that I'm going to mention a little bit later. Are very important for creating the structures in soil that we need for free living nitrogen fixing to take place.

17:55 This was something that really brought the whole issue home to me very clearly. This is Sarah and Ilka in Finland and they were converting their farm to organics and they were doing a trial with something like 20 different organic fertilizers that were all carbon-based fertilizer like different kinds of compost.

18:15 And we were looking at the roots of the wheat plants to see whether these fertilizers, these biological fertilizers, what difference they were making to the riser sheaths on the plants. And what we found was that every single one of the 20 treatments that we looked at had beautiful riser sheaths on the crown roots that were the roots coming out of the crowns of the plants but below the seed, all of the roots were completely white and clean and had no soil sticking to them whatsoever.

19:00 Here we have our wheat seed here and these amazingly clean white roots, seminal roots coming down from the seed. Didn't wash these plants, just dug them out, shook the soil off them. And these beautiful riser sheaths on the crown roots. And it was I've never seen it like that before.

19:21 And here's another one, here's the seed here. These are incredibly clean roots and these beautiful riser sheaths here, all on the same plant. And I was just totally puzzled. I couldn't figure it out because they were converting to organic so I assume that they weren't going to be using any nitrogen fertilizer.

19:40 And we went back and had some lunch and talked about it and in the end I said to Sarah, you know look, you haven't used any nitrogen fertilizer here, have you? And she said oh yes, the scientist that was helping us set up this trial and conduct this research in a way that was going to give us meaningful results said that because these biological fertilizers that we were using which was a range of different kinds of compost had different carbon to nitrogen ratios, and in order to take that out of the experiment as a factor we needed to apply nitrogen to everything to equalize the amount of nitrogen in the plot. So all of the treatments had 80 units of N placed under the seed.

20:20 So if you want to see what nitrogen placed under the seed does to wheat roots, there, there it is. Absolute classic here are the seeds, nitrogen placed under the seed, there is no possibility for any nitrogen fixing to happen in that environment. But up here where the crown roots are in contact with the various forms of compost that they were using, beautiful riser sheaths. And there will be free living nitrogen fixes living inside those riser shifts because it's a micro-aerobic environment, a low partial pressure of oxygen.

20:59 And in fact if nitrogen hadn't been placed under these seeds there would have been riser sheaths on these roots here as well. So in the secrets of the soil, two weeks ago I talked about the fungal energy channel and I showed this photograph. I think I probably showed it every time, I might even show it again next week. I just love it so much.

21:19 So over here on the left we have a plant root and on the right we have soil particles. And this is what we would be able to see if we used a microscope to look in underneath or look into a riser sheath. We see all these fungi, this fungal hyphae that are extending from the plant root out to the riser sheath. And of course they're helping to bind the soil particles that are clinging to the roots to create that riser sheath in the first place.

21:47 But this space inside here, this is going to be a low oxygen environment. It's going to be low partial pressure of oxygen in here. And there are going to be literally trillions of bacteria and archaea, all feeding on root exudates. But also, even some of them will be forming biofilms on the hyphae of this fungi. And it's a very, very rich environment for free living nitrogen fixes.

22:15 If you think about it, we have this belief that number one we have to add nitrogen for plants to grow because we know that they do need nitrogen and number two that legumes are the only plants that form a relationship with nitrogen fixing bacteria. Well if you really think about that, if legumes were the only plants that were able to form a relationship with nitrogen-fixing bacteria, that would probably be about the only plants that would be on the planet because no other plants would be able to survive.

22:46 And yet you can go to plenty of environments and look into the plant community and see there are no legumes there. And everything else is nice and green and everything else is growing perfectly well. So obviously every single green plant has the capacity to form a relationship with free living nitrogen fixing bacteria. Otherwise it couldn't be green because the chlorophyll, the pigment that makes a plant green, is actually part of a protein complex. So it can't be green unless the plant is able to access nitrogen from somewhere.

23:20 So the plant is going to access that nitrogen through microbial intermediaries. And they need a specialized environment in which to thrive. They need an environment where there's lots of energy coming in. And that energy is going to come through that fungal energy channel through plant root exudates. And they need some kind of a structure like a riser sheath or a water stable aggregate, that's a root supported water stable aggregate. In other words, it's going to be fine feeder roots coming into that aggregate and actually building that aggregate.

23:54 And in those environments the plant is going to be able to obtain all of the nitrogen that it needs. And I think I also used this slide last week. This is just the brown bit down the center is actually a plant root and all the creamy network here are the hyphae of, in this case ectomycorrhizal fungi, but there are a lot of the other fungi that are in soil we can't see with the naked eye or even under a microscope. We can't see them. And yet this is what it's going to look like in the soil when the fungal energy channel is open and operating.

24:32 So these fungi, this fungal hyphae, are going to be taking energy that was derived from photosynthesis.

24:38 That the plant has channeled down to its roots and is pumping out into the soil sociobiome through this fungal hyphae. It's going to be taking that energy out to colonies of bacteria and archaea that are going to be able to fix nitrogen in water stable aggregates. And so the plant associated fungi in this fungal energy channel are going to be transporting energy to nitrogen fixing bacteria and archaea because remember that production of the nitrogenase enzyme and the breaking of that triple bond actually requires quite a lot of energy and they're also going to be transporting organic nitrogen back to plant roots.

25:20 So there was a question came up. I'm not sure whether it was last week or the week before about our fungi able to fix atmospheric nitrogen. Well the answer is no. But fungi are very, very important. Plant associated fungi are very important for bringing nitrogen back to plants and they will bring it back in the organic form. They're going to bring it back as amino acids and the reason they transport it as amino acids is because that is the most efficient way, energy efficient way to transport them. And then once they're inside the plant, the plant can very easily assemble amino acids into complete proteins. It doesn't take much energy for the plant to make all the proteins that it needs from amino acids.

26:03 If the plant takes up inorganic nitrogen as we are led to believe by just about every textbook that you read about nitrogen, will say that plants prefer to assimilate nitrogen, usually as nitrate. Nitrate would be the preferred option and then ammonium would be the second preference. Well that's actually not true. That's only because people have looked in environments where that's really been the only options that plants have had. If they take inorganic nitrogen up into the leaves and the stems, they then have to produce a whole lot more carbohydrate to add to that nitrogen, that inorganic nitrogen, to transform it into organic, into amino acids and into protein. It requires a huge metabolic cost to the plant to transform inorganic nitrogen into protein and often the plants are not able to do it. So there the nitrogen remains in an inorganic form in the plants. And that's when we have livestock that suffer from nitrate poisoning or we have even metabolic issues in livestock from consuming plants that are very high in nitrates.

27:20 We actually don't want any nitrate in soil in plants in our animals or in our water. And the way to avoid having nitrate in any of those environments is not to use it in the first place. And if we are supporting that whole fungal energy channel and that sociobiome, even though the bacteria and the archaea are going to fix nitrogen as firstly as ammonia and then very rapidly convert that to ammonium, it is then going to go into microbial biomass. It's going to be part of the bodies of all the things that live in soil. And it's going to be in that microbial biomass in the amino form. So it's going to be organic. It won't show up on a soil test as available. And I have seen multiple soil tests where the soil has virtually no detectable end. A leaf test will show that there's virtually no inorganic end in the leaves. And if an agronomist looked at that soil test and that leaf test, they would say this plant is not capable of producing anything. And yet those particular plants will have some of the highest grain yields in the district and the highest protein content in the grain in that district. And that is because in the soil and in the plant the nitrogen was in an organic form. It's not leachable. It's not mobile unless it's transported by fungi. And that is the form we want all of our nitrogen to be in. And it will be if we are. All we need to do as farmers is support that fungal energy channel.

29:03 I've also said multiple times in the past that 85 to 90 percent of plant nutrient acquisition has microbially mediated us because I like using lots of big words. But even when we apply synthetic fertilizers to soil as a general rule, they cannot get into plants unless there's some kind of transformation takes place in the microbiomes. The microbes are just so incredibly important for plant nutrient acquisition. And as I mentioned last week or the week before, we need lots and lots of different kinds of microbes living in all the different compartments if you like of the soil and the plants. We want we want microbes around the rhizosphere. We want microbes in the stems and the leaves, the fruits, the flowers. And we actually want to incorporate, we want the plant to incorporate microbes into the seed and carry those through to the next generation in its core microbiome. And ideally a lot of those microbes would be bacteria and archaea that have the ability to fix atmospheric nitrogen and they're going to interact with a whole lot of other microbes that are in that sociobiome.

30:13 Because it's never a case of one single microbe acting alone. And this has been the issue with a lot of research. There has been a lot of research into trying to isolate individual nitrogen fixing bacteria or even individual isolates of some that are better able to fix nitrogen than others, even within one species of nitrogen fixing bacteria. But a lot of that has not come to anything because you can't just apply one species of bacteria to soil or one species of bacteria to seeds or to plants and expect it to be able to function. It requires that work as a team so bacteria and archaea and fungi, everything that lives in soil, works together. It is a sociobiome. We just need to create the right conditions for all of those bacteria to work together and we'll get the desired result.

31:37 And we have to remember what I have already mentioned before is that we want different kinds of plants that have different functional traits. In other words, they come from different plant families because if the microbiomes of all the plants that are growing together in a community are similar, in other words if we have a monoculture of something, then the microbiomes have a negative feedback effect on nutrient acquisition. A microbiome will recognize that the neighboring microbiomes are the same as it and it will not cooperate with those neighboring microbiomes and will be very competitive for nutrients. If we have dissimilar microbiomes, in other words we have plants with different functional traits, they're from different plant families growing together in a community and the microbiomes of the plant detect that the others around it are different to itself or dissimilar to itself, there will be a positive feedback on nutrient acquisition and plants will actually exchange nutrients through the common mycorrhizal network and will help each other. Some plants that are able to like there might be some plants with deep tap roots that are able to access minerals.

32:48 From the subsoil while others have shallow fibrous root systems not able to access those same particularly trace elements. Those things can be shared through the common mycorrhizal network provided the plants have dissimilar microbiomes. So it's really important that we look at those functional groups, and in our mixtures, this is some place that you may put in a pasture. But in our cover crop mixes or in our companions, when we need to look at having different plant families to obtain the best outcome in terms of nitrogen fixing. So we could have a plant community. I know that there are legumes in that particular diagram, so we have plantain, red clover, chicory, pea, ryegrass, swiss, and which you will call alfalfa, beets, fescue, daniel and coxwood in that diagram. I'd like to see a lot more diversity than that, but that's a start. And quite a few of those things are legumes. Will red clover, pea, and alfalfa are legumes, but we could take the legumes out of that system and just have if we have at least four plant families in there, it will be equally as good at fixing nitrogen. In fact, diverse systems with no legumes, provided we have four functional groups—at least four functional groups—will fix more nitrogen than a system with legumes.

34:16 So people talk about how many species should I have in a mix? And you know, maybe six species in mixed orange species in a mix, and I said, well, if they're all legumes, it probably will have a negative effect. You want, you know, four plant families and two species from each or something like that.

34:32 So here's a practical example of that. This is a cover crop demonstration I saw on a research farm in Ontario in Canada. And there were strips probably about 20 yards wide, I guess, of a whole lot of different cover crop species planted as monocultures and then mixes of those right up to something like I think a 12-way mix.

34:56 So in this example here we're looking at just radish grown on its own. And all of these plots actually received a base application of an MPK fertilizer, so it has been fertilized, but it's very nitrogen deficient. And right next to it on the right hand side was done it again was a mix of radish with or planted at the same time, everything the same. Radish with a little bit of oats and sunflower and phacelia.

35:32 So you can see the radish leaves in here are all beautiful and green. I'm sure you all recognize oats. There's a celia plant here and sunflower here. So what we have is not a huge amount of other things in there, just a smattering of other kinds of plants in there, but we actually have four plant families in that particular case. So even though in this research they were looking at all these different combinations and different mixes, there wasn't any emphasis on functional dissimilarity. It just so happened that in this particular case there were four plant families in this mix, and there is no obvious signs of lack of nitrogen.

36:16 And the other interesting thing about this photograph is there are no legumes in this mix. So we have sunflower and asteraceae, oats in poachy, radish in brassicaceae, and phacelia in embarrassing. We don't have any legumes in there, and there is no nitrogen deficiency. So if I just splice those photos and put them side by side, you can see the huge difference. Plants were much larger and obviously not nitrogen deficient, and yet the whole trial received the same basal application of nitrogen.

36:50 So high analysis fertilizers are merely a substitute for plant diversity. So it's not really going to be that hard for us to wean off nitrogen once we start looking at plant diversity. Once we start looking at plant diversity.

37:10 I think I need to get a new mouse. We're having a mouse played here in Australia at the moment, so maybe I can go and get one of those.

37:18 The antibiotic experiment. I know I mention it every time. It's just because there is so much good research that has been done there and so much great information. But when they looked at one, two, four, eight or sixteen different plant species and four functional groups—the functional groups were grasses, legumes, tall herbs and short herbs, and the tall and short herbs were non-leguminous—and they looked at biomass production, beneficial insects, or microbial activity, water balance, soil carbon, nitrogen, and this is just an overview of the site, but the one particular bit of this experiment that I want to talk about today is the nitrogen part of it.

37:57 So with those different numbers of plant species, remember all four functional groups. So eight plant species, for example, was two species from each of four functional groups. Sixteen plant species was four species from each of four functional groups, not just any 16 plants. And this is a multi-factorial experiment where they've looked at zero, 100 or 200 pounds of nitrogen per acre per year. It was actually kilograms of nitrogen per hectare, but kilograms per hectare and pounds per acre roughly equivalent. And it's multifactorial, so you might have just a monoculture with one species with no nitrogen or 100 pounds per acre or 200 pounds per acre, right up to 16 plant species with no nitrogen, 100 or 200 pounds of nitrogen per acre. And what they found in this experiment was that if they had 8 or 16 plant species with no nitrogen, it produced more biomass, like it produced a greater plant yield than one or two species with 200 pounds of nitrogen per acre per year.

39:05 If you have a monoculture with 200 pounds of nitrogen per acre per year, it is not able to produce as much as a diverse polyculture with no nitrogen. And this result has been replicated around the world in many, many different experiments. There's research underway in Ireland at the moment, for example, looking at mostly pastures for sheep and for dairy and for beef cattle. And they're finding there that they can completely eliminate nitrogen through plant diversity. In fact, even something like 350 kilos per 350 kilos of N per hectare, which is something like 760 kilograms of urea well per hectare—like let's say nearly 800 pounds of urea per acre, nearly 800 pounds of urea per acre—cannot produce as much yield as having a plant community with four functional groups. I think this is really—I keep saying it and I'm going to say it again: the way of the future is going to be polycultures in every aspect of agricultural production. And I'll talk more about that next week when I'm talking about orchards and venues.

40:32 So if levels of microbial diversity have been reduced in soil through—think of all the things that we do in agriculture: bare fallows. We don't have any photosynthesis, so we're not supporting any microbes. We use high rates of nitrogen fertilizer that we know throw the soil completely out of balance, inhibit root exudation. And if we've inhibited root exudation, then we're not supporting microbes. Fungicides—what are fungicides going to do to the fungal energy channel? Obliterated. Pesticides are highly toxic. We really don't want to be using.

41:05 Pesticides in agriculture, anyway if we can avoid it. An inappropriate grazing management, which I'm not really going into in these webinars because we're talking about cropping situations. But if we are removing all the photosynthetic capacity of the pasture by overgrazing it, then there's not going to be enough carbon being channeled to the soil to support the soil microbiome. So within any of those situations, and those situations occur throughout the world in nearly all of our agricultural soil, biological nitrogen fixation is going to be inhibited. And that is why farmers have had to resort to using inorganic nitrogen fertilizer because they have not supported the natural process in soil and probably haven't realized that even something like a bare fallow, for example, is going to have a hugely detrimental effect on the nitrogen dynamics in your soil.

42:02 So how can we increase microbial diversity? In other words, how can we go the other way? Or we just need to reverse all of those things. We need to make sure that we have year-long green. Make sure that we never have bare ground and we want that year-long green to be biodiverse. So we want a minimum of four plant families in our biodiverse year-long green cover. And we can also, particularly in the transitioning process when we're weaning off nitrogen, use microbial stimulants. They're particularly effective on the seed because they're going to mimic the microbial signaling that will take place in a diverse soil microbiome. So as I've explained in previous webinars, plants use chemical signals or biochemical signals to communicate with soil microbes. Microbes use biochemical signals to communicate with plants and microbes use biochemical signals to communicate with each other. And those biochemical signals are going to be very rich in mediums like in the gut of an earthworm or in a fermented compost or something like that. We can just take a dilute extract of those kinds of materials and we will be taking out the chemical signaling molecules or the auto-inducers, if you like, and applying those to seeds. We're not going to be applying microbes to seeds. We're just going to be applying the signaling molecules from microbes to seeds and the seeds will interpret those as an inner microbially rich environment. And they'll produce lots of exudates to support those microbes and just kick start the whole microbial diversity. Just kick start that whole process of plants supporting microbes and microbes supporting plants.

43:57 If you have been using a lot of nitrogen fertilizer for quite a while, you're going to have very low levels of natural free-living nitrogen-fixing bacteria in your soil. They do take a while to replicate. With phosphorus it's not an issue because the microbes that are involved in phosphorus acquisition can very rapidly build up in soil. It just takes the free-living nitrogen fixers a little while, something like about three years. So if you've been using a lot and you don't want your yields to decline in the first year, it's best if you just reduce it by about 20%. But also if you don't put it on the seed and don't put it anywhere near the seed, so you're going to reduce it. But you're also going to not put it in the soil. You'll use it as a foliar or you will use an organic form of nitrogen like fish hydrolysate or something like that. In year two you can reduce it another thirty percent. In year three, another fifty percent. So let's say you were using a hundred pounds per acre. In the first year you just go down to 80 pounds per acre. In the second year you could drop it to 50. In the third year, down to 25 pounds per acre. And then indefinitely, if you feel that your plants do need a little bit of inorganic nitrogen, you can use five pounds per acre with no detrimental effects on the soil microbiome.

45:22 So just to give you an example, five pounds of nitrogen per acre would be say 25 pounds per acre of sulfate of ammonia because it's 20% nitrogen. So you need to look at the product you're using and what percentage of it is nitrogen. So when I say five pounds of nitrogen per acre, I mean the nitrogen itself. The sulfate of ammonia is quite a useful inorganic nitrogen fertilizer to use because a lot of soils are slightly deficient in sulfur, especially if you're a long way from the sea. So it doesn't hurt. I'm not saying that all inorganic fertilizers are bad. And if they're used at very low rates, they're not bad. But what we are seeing in agricultural systems around the world is that in the early days, maybe the 1970s, 1980s, people were using relatively small amounts of nitrogen fertilizer. And now they're using massive amounts. So over time the amount that's being applied has been increasingly increased and that's because plants haven't been responding to it. So people have been put in a situation of putting more and more on, trying to actually get a response or even to maintain yield. So the idea is that we need to cut that back. But you don't have to eliminate it completely.

46:39 And if you can find organic forms of nitrogen, for example fish hydrolysate, they're not going to inhibit the functioning of the soil microbiome. But again, don't need to apply a whole heap. The application rate for fish hydrolysate will be something like 10 liters per hectare, which is probably about 10 pints per acre. We're not talking about putting gallons of this stuff on. And always use plant leaf tests to see whether your plants need nitrogen or not. And if they do, apply it as a foliar only if they need it. And so over time, by cutting back, by introducing diversity, by making sure you never have bare soil, all of these things—it's like a jigsaw puzzle. You need to put all the pieces in place. And you need to keep monitoring and see how you're going. And if you do leaf tests and your plants need nitrogen, then apply it because we don't want you to be losing yield. But if you apply it as a foliar, it's not going to have an effect on the soil microbiome. And plants can take it up through their leaves. We just want to keep everything fully functional and we just want to transition nice and smoothly into a situation where you don't need to use any at all. And you'll be building soil. That'll be one of the great things. You need to go out with a spade, dig holes, look to see whether your soil is aggregating, look for riser sheets, all these positive things that over time will give you, as a farmer, incredibly positive feedback about how your soils are going and how everything is working together as it should in your soils. And you'll, as a person, feel more connected to what it is that you're doing rather than just going out applying lots of fertilizer, then having to use fungicides, then having to use insecticides, then worrying about all the pests and diseases and the cost associated with producing a crop. And you know, what if the price falls? What if it cost me more to put this crop in than what I get back for it? It's a very stressful situation. And that situation can be just turned around.

48:54 To one that is a very pleasant experience to actually see that you're building soil and that your plants don't need any inorganic fertilizers. So that's the end of my formal part of my presentation, and I'm now open for questions.

49:17 I don't know why that one picture gets me every time, but the wheat with the nitrogen underneath is just such a telling image. I mean, you know they say a picture's worth a thousand words. I don't know how you can get around that. I just love that picture. So thanks for putting it in there. I appreciate that. You can show that anytime. It comes, I use it every time now whenever I talk nitrogen. I can't help using that one. But I mean, you could show a fence line effect like this soil came from this side of the fence and this came from that side. And I mean it would also be easy to manipulate that, you know, you could choose where you did it. But we dug those wheat plants out of every single one of those 20 test plots, and every single one had that same thing. I was like, what is going on here? And I kept saying to Sarah, you know, have you used something, some kind of herbicide that would have a residual effect, or some kind of poison in this soil? We just couldn't figure it out.

50:23 Well, I'm going to go ahead. We've got plenty of questions to get to, so I'm going to jump right into it. What I wanted to try and do this evening is try and bunch some of these questions up so we can get to as many as possible. So if you're typing a question out and I don't address it read it exactly the way that you say it, that's kind of what I'm trying to do is get things more on themes here this evening. But I thought this was kind of funny. Shorty said, can you explain what a funny protein is?

50:52 Yeah, a funny protein is not a complete protein. That was a term that Jerry Brunetti came up with. So a funny protein is when a plant takes up inorganic nitrogen but is not able to complete the process of converting that into a protein. It remains in the plant in an inorganic form. What happens is that if you send leaves off or you know a plant tissue test to the lab to have like a forage analysis or something done on it, all they are going to do is measure the amount of nitrogen that's in that plant and multiply it by a factor. In Australia the factor is 6.25. So they will say every unit of nitrogen is equivalent to 6.25 units of protein. So just say for example there was 2 nitrogen there, it's going to come out at you know 14 or something protein. But that nitrogen might not be protein. And so that's what we call funny protein. It's not. It's what the lab will tell you it was protein, but they didn't measure protein. They just measured nitrogen. We see it time and time again, particularly in forage samples where farmers have used a lot of urea or something to try and get their grass to grow. And the grass will grow taller and it will look green, but the livestock don't do very well on it. They're in fact going to do better on shorter grass that has got complete proteins. So yeah, that's what funny protein is. Jerry Brunetti came up with that.

52:24 Okay, I have two questions here in regards to sap analysis. John Kemp champions plant sap test has a more accurate look into what the plant contains in nutrients. Do you have any opinion on sap tests?

52:39 They're used pretty widely in like intensive horticultural situations. For example, in Europe where you've got big tunnels and you're producing thousands of lettuces and tomatoes and things like every day. And it's a way of very closely monitoring what's happening in the plant. In fact, in some of those situations there will be a sap test done basically every day to find out what's going on in the plant. And it does give you a more immediate idea of whether that plant actually needs something at that time. I think that if you're focusing on the fungal energy channel and getting the soil sociobiome up and running and you're looking at to see whether plants have got riser sheets and whether aggregates are forming, you don't need a constant looking at sap. I think in a horticultural situation, maybe yes. High value horticultural crops would justify that. But if you're growing field crops or pastures, I think a leaf test is perfectly fine.

53:46 Albert says, can you clarify that if you have companion plants without a legume, that the bacteria is still fixing nitrogen and making it available for the plants? Can I confirm that? Well, yes, the research shows that in fact if we have four functional groups without legumes, we'll fix the soil. We'll fix more nitrogen. Or the soil sociobiome will fix more nitrogen than one that has legumes in it. That's what the research shows. We're better off without legumes. But I mean, we've used legume lithiums in a way to me are almost like a de facto form of nitrogen fertilizer. We've got a system that's not working. We've usually got a monoculture, and we'll put a legume in there because the bacteria that are associated with that legume can fix nitrogen. So it kind of gets us out of the situation where things aren't working properly. But if we're in a situation where everything is working properly and we've got enough functional diversity in our plant community, we honestly do not need legumes in there, and they in fact can be detrimental to that whole process. They're not necessary when we have everything functioning properly.

54:59 So kind of along the same lines, can bacteria feed nitrogen to the plants without fungi? How can we increase the fungi in our soils, and is there an ideal ratio that you're trying to aim for?

55:12 Yeah, we talked about fungal to bacterial ratios last week, I think, or the week before. I would definitely like to see a ratio of more than one to one. I'd like to see fungal to bacteria being more like two to one. But in answer to the question, bacteria can definitely feed nitrogen directly to plants, and there'll be bacteria all around the roots in a healthy soil. There'll be biofilms of bacteria all around plant roots, particularly the young roots, young actively growing roots. If you've listened to any of James White's webinars—and I think you've had Professor James White actually with Green Cover has presented a webinar—on how plant roots can internalize bacteria that contain nitrogen and strip them of that nitrogen, and then that's the rhizophagy cycle that he talks about. So that is one way that plants can obtain nitrogen from bacteria. But they can also internalize nitrogen-fixing bacteria and just maintain them within the entire plant, like in the leaves or somewhere. They don't have to be down in the roots as nitrogen-fixing endophytes.

56:20 Okay, are the Janelia trials measuring plant biomass or crop yield? And I'm going to add on to that, is there a good place to go for the research on those Janelia trials? Is there some YouTube videos or anything?

56:35 Yeah, if you just put that into Google, just put 'JANIO biodiversity experiment YouTube,' there is a little YouTube video I think it's about seven or eight minutes. It's absolutely fantastic. It's one of my go-to. Yeah, if somebody wants to know.

1:05:07 Up microbes from the soil if it needs to as endophytes, beneficial endophytes, and that's something I am going to be talking about next week. So that's actually probably a good segue into what I'm going to be talking about next week. If we have in a horticultural situation we have some perennial plants, like our fruit trees or our grapevines or whatever they might be, and in the inter-row we can have this multi-species cover crop that is going to create a diverse microbiome in the inter-row that our perennial plants are able to tap into and they can actually take endophytes from that inter-row and use them to combat diseases in the perennial plants themselves. And that's something I will talk about next week. It definitely happens in diverse systems, so diversity is going to be the key there.

1:06:02 Okay, this is a rather interesting question, something I have not thought about here, but Dede says great to see you Christine. Researchers are saying that the reason plants are higher in carbohydrates and also lower in nutrients than they used to be is because of the increased levels of CO2 in the atmosphere. But it sounds like plants are trying to process inorganic nitrogen in a not available form might be part of the issue. Do you have any thoughts on that?

1:06:37 Oh, it's too complicated for me. Oh, I just think, you know, if plants are taking up inorganic nitrogen, that's going to be an issue for just about everything that you can think of, including human nutrition, animal nutrition. Yeah, global climate, everything. It's all—there is nothing I have nothing good to say about inorganic nitrogen, and we do not want to have it in our soil. We don't want to have it in our plants. But I can't directly answer that question, sorry.

1:07:13 Have you heard or have any thoughts on adding humic acid to nitrogen fertilizer in the transition period to buffer those negative effects? I have heard of people doing that and I'm just not really sure about that one. That's another one I don't know whether that's just a sales pitch or whether that actually works. You're better off just using an organic nitrogen fertilizer, as I said, something like fish hydrolysate. You don't have to buffer anything then, and it will still be—those amino acids will be taken, absorbed by plant leaves. You will still get the nitrogen effect. The plants will still benefit from the nitrogen in that, and why don't we just avoid inorganic nitrogen altogether or more or less altogether.

1:08:10 Willie asked: do the free living nitrogen fixing bacteria increase in fixing capacity as the diversity increases? Do the free living fixers have the same fixing capacity as do the legume associated fixers? I'm trying to wrap my head around that one as well. That came from Willy Pretorius. I know who that came from. He's always asking a hard question. What was the first question again? Do the free living nitrogen fixing bacteria increase in their fixing capacity as diversity increases? Do they get more efficient as your diversity increases? Well, I mean the answer to that question is that as plant diversity increases, microbial diversity increases, and microbes function better in diverse teams. You know, when there's some microbes that can do one thing and others that can do another and they work together, then the overall efficiency of the system improves. Teamwork in the microbial world is always going to be better than one micro trying to do everything on its own. So even though the efficiency of one particular species of nitrogen fixing bacteria may not necessarily increase when you have a whole lot of different species also, they're going to be working with phosphorus solubilizing bacteria and they're going to be working with bacteria that are able to activate trace elements and minerals and all those sorts of things. The whole teamwork is what's going to be important, and you're going to lift the energy level of the whole system to a higher level. And yes, it will fix more. I mean, it's going to be able to—when the sociobiome is really functioning effectively, it's going to be able to fix all the nitrogen that a big crop like corn, for example, needs. So yes, it is going to be able to. You know, I can't really see why you would want to be relating that to what can legumes, you know, how much nitrogen can write. I mean, we know that the rhizobium associated with legumes, for example, are hugely affected by the environment that the legume is growing in and how much nitrogen fertilizer you use. If you put nitrogen fertilizer on a legume, the rhizobium bacteria in the nodules stop fixing nitrogen. And the same thing is going to happen to the sociobiome. If we add nitrogen fertilizer, then any free living nitrogen fixing bacteria in there that are capable of fixing nitrogen are going to stop doing it simply because the nitrogen is already available. So I'm still not quite sure about that question. I'd have to say it's a typical South African question.

1:10:52 We are listening the other day about does it really matter. Just get that soil building happening and get those riser sheets and get those aggregates forming because there are going to be so many physical, biological, chemical benefits to the whole ecosystem. Okay, and if you can see soil building happening, then everything else is going to happen too.

1:11:18 I'm beginning to learn there's two kinds of people in this space. Those that really want to understand every detail what's happening, and then there's people like me that are like, well, I think this works, I'm going to just go for it. I'm with you now. All you need is a spade. There you go. Clara is actually in Ireland, so she is wondering if you know where in Ireland that experiment on plant diversity was conducted or how she can find out more on that.

1:11:50 Okay, so the guy that did the first experiment that I was referring to was Thomas Maloney, and he did the experiment while he was with Chigaski and he did it as his PhD. So if you Google Tom Maloney, and it was with pastures that were grown for silage, but if you want the link, how about I send you that link now. So I think Peace might have already found the one to the In-a-Biodiversity experiment, but I'll send you the link to that Irish research because it was really insightful. They used, I'm pretty sure it was 320 kilos per hectare of N. And then as a follow-on from that, there was the Smart Grass project, which was looking at how much forage can you produce in a diverse pasture without using nitrogen just to try and help Irish livestock producers move away from using nitrogen because it was so detrimental to the wider environment, particularly to the water. And then that transformed into Smart Sward. So it started off as Smart Grass, and then they realized, hey, it's not actually about grass, it's about all the other things, and it's now called the Smart Sward project. So if she Googles Smart Sport to find out, a lot has been undertaken by the University College of Dublin in Dublin and in combination with Chagask and several other organizations. Smart Grass, Smart Sword, and Thomas Maloney will find it, and I think Thomas Maloney.

1:13:22 He's actually with our seed company now. He might be a competitor for green color, DLS seeds or something like that, I think. He's weak.

1:13:36 Randy says how late is too late to tissue test. Gosh, you know if your plants look perfectly healthy and they're a good green color, you probably don't need to do a tissue test at all. I mean you would only do it if you thought that there was some issue, I think. You know it's going to cost you money to go out and collect samples and send them off. Really, from the day the plants germinate you need to be looking at their roots to see are they forming riser sheets. They're not forming riser sheets and the ceilings don't look all that good, well you want to be doing tissue tests, you know probably when they're three or four weeks old.

1:14:27 Josh has an observation that his cool season annuals tend to grow more slowly than his neighbor who does apply inorganic nitrogen. Is the release of nitrogen through the organic process temperature dependent at all, and if so what temperature does it typically start to catch up with nitrogen fertilizer. His cool season annuals—what is he using them for? Is this for grain production or is he talking about it past? Can you just start, can you read that question again please now. Yeah, and Josh, if you are, if you're on, it'd be great if you could type in as well what the goal is on that crop that you're growing. Just as I've noticed my cool season annuals grow more slowly in cool weather than my neighbors in organic nitrogen supplemented cereals. So definitely a cereal but I'm not sure if it's a wheat or rye.

1:15:22 All right, now that's a really good observation, and then he's just put grazing there. All right, well if it was for the grain and that was something I should have mentioned: if you're going to transition from a high input system to one that's going to be more supportive of the soil biome, in the early stages of growth your crops are not going to look like your neighbor's crops across the fence because they've basically put them on steroids. They've just given them lots of water-soluble nitrogen, lots of water soluble nitrogen, and they're going to grow lots of leaves in a really short amount of time. They're going to have a dysfunctional root system and they're going to probably fall over the first plant pathogen that comes through, the first lot of some kind of fungal pathogen. They're going to be susceptible to it, or if there's an insect pest they're going to be susceptible to it.

1:16:13 Your plants, if you've got let's just call it a biological system, are going to invest a lot of energy into producing roots and riser sheets and supporting the soil microbiome. They're going to be very resilient plants, are going to be very nutrient dense plants. When it gets to right through to the final stage of yield, you'll find that even though you're, if we're talking about a cereal now that's been grown for grain, even though in the early stages your neighbor's going to be laughing at you, your neighbor is not going to be laughing at you when you're harvesting that crop because you're going to have nutrient dense grain. It's going to be plumper, it's going to be heavier. The falling numbers are going to be higher. All those things, I don't know what kind of tests you use in the United States but the protein content is going to be higher. Everything about that grain is going to be more robust and it's going to be more nutrient dense, and the plants are going to be more resilient.

1:17:06 If there's a drought or if there's water logging or any kind of stress or a late frost or something like that, so it's like the hare and the tortoise basically. At the end of the race your grain is going to be superior to your neighbors and you're going to have more money in the bank than your neighbor.

1:17:23 Now if this is for grazing it might well be that the cool season annuals might only be let's say half the height of the neighbors, but they could have double the nutrient density. You'll find that if you're testing brix, probably need to hop over the fence and measure brix levels on your neighbors cool season annuals. You might find that if they're using high nitrogen fertilizers that their brix circles might be two or three, something like that. Yours might be fifteen or sixteen, which means that you have far more protein and energy and vitamins and minerals and everything in your pasture even though it's shorter.

1:18:03 The feed conversion efficiency is going to be much greater and your livestock will actually do better on less. If you like, then it's like you could have more and more of something that's got nothing in it. I mean just imagine like say a huge pile of lettuce. Like if you're a person and you just come into the dining table, it's just covered in a huge pile of lettuce, it's got nothing in it, or a small bowl of salad that's got lots of different herbs and nutrient dense foods. You know, like it's not the volume that's important, it's how much nutrient is actually in there.

1:18:37 So if it's biologically grown and it's grown in soil that's supportive of the microbes that are able to access the nutrients that and the trace elements the plant needs, it can be half the height but still more productive in terms of livestock production. If you're looking at live weight gains, they're correlated almost directly with brix. So he needs to get a refractometer, measure the brix levels of his crop and the brix levels of the neighbors now.

1:19:07 If your crop is only half the height of the neighbors and the brix levels are the same, you have a problem because you have something that hasn't grown as well and it's also not functioning either. So that's maybe when you need to do some tissue tests and find out what it hasn't got in it and start thinking about why. But I think you'll find the brix levels will be much higher in the shorter plants, which means that the energy and the protein and the minerals and trace elements will be great for your livestock if it's for grazing.

1:19:37 And also if there's cereals, why has he not got four functional groups in there. So I'm glad you brought up four functional groups and we did touch on this last week and the week before that, but there tends to be a lot of questions around this topic of four groups. A lot of people are asking, well, Matthew first asks are legumes in your plant community bad, which I'm assuming the answer is no, but I'll let you address that. And what are some examples of the companions, especially in pastures? I'm getting a lot of questions for those four functional groups. Do you have any examples of plants that they can be putting in there?

1:20:18 Okay, if we just go back to the Irish research, the four functional families that they've used for pastures—so this is for livestock production—have been grasses and legumes. The legumes in that case are clovers and also alfalfa and bird's foot trefoil, sandpoint, all those kinds of things. They're all legumes even though they're different species, they're still in the one functional group. And then they've got chicory in there, which is in Asteraceae, which is in the daisy family, and plantain, which is in Plantaginaceae. So they're four different plant families that have been throughout all of the Irish research. I don't know whether it was good luck or good management, but I love the Irish so I'll say probably both.

1:21:11 They've got four functional groups in there and it has just worked extremely well. My question is, is maybe that all you need? The photograph I showed before, of a cover crop situation where there was radish, which is in Brazil Casey, switches in poaching, sunflowers in asteroids in the daisy family, and then facilia which is in braginase, we had four functional groups there and that looked incredibly healthy.

1:21:39 So my question is, did we actually need to go more than that? Did we need to have any more than four species, provided that they were from four functional groups? I mean, it might even come back to, as long as you've got four functional groups, you've got enough. But certainly in the Irish situation, they do only have four functional groups and they've found that they've been able to cut nitrogen out of the system completely and still maintain yield, and that's for grazing.

1:22:09 And there are some Irish dairy farmers that have gone up to 20 species. So they start putting in a whole lot of herbs, like sheep's parsley for example, which is in parsley, it's in apac, the carrot family. They use burnet, which is also quite commonly used in the United States, and that's in the rosaceae family. So it's, believe it or not, in the same family as apples and roses and those kinds of things. So that's a very different functional group.

1:22:38 I think one of the reasons burnet is so popular and so widely used in pastures, it's got condensed tannins in it, it's anthelmintic, it stimulates feed conversion efficiency. It's an incredible plant for including in pastures. So I would definitely be putting chicory and plantain in there and burnet in addition to whatever grasses and legumes. Yeah, small burnet, I see Kate's put a comment there. Good, you put it in your mixes, that's great. That would be the one. If the Irish were going to put something else in there, I would put burnet in there.

1:23:23 So this is not necessarily in regards to nitrogen, but you made a comment there about maybe those four to eight species is all we need. How does that differ then? I've heard your talk and I believe we have that on our YouTube page about the quorum sensing, and you've talked there about the number 12 being kind of an important species, and maybe we're going back to we don't need to understand it, just plant it, move on. But seem to be kind of two different things that we're saying there. Do you want to comment on the quorum sensing aspect?

1:23:54 That's really good point, Noah, because originally when people started experimenting with different numbers of species, you know, like Gabe Brown would have been one of the leaders in that, putting in different species, and Jay Fuhrer, putting in different numbers of plants together. And they did that experiment in the early civil conservation district, when was that, back in 2006 or something, where they had that six-way mix that was so incredibly drought-tolerant compared to all of their monocultures. And that was when people really started looking at, okay, so do you need six species, do you need eight species? And then farmers in New Zealand started using 12 species.

1:24:33 They were using 12 plant species and getting incredible results from it. And we're thinking, okay, so maybe you do need to have 12. But then when you looked at the 12s that they were using, probably four of those were grasses, four might have been legumes, so there's eight out of the twelve. And then the other four would have been things like chicory and plantain and maybe burnet and sheep's parsley.

1:24:56 So that in actual fact, even though they had 12 species, they may have only had four functional groups. There's been some really good research results coming out of England where people have had six plant families or sometimes even eight plant families in a cover, and you know, getting rapid soil building and phenomenal crops. The follow-on crop has been phenomenal.

1:25:21 So I'm thinking that in the early days we thought it was all about species. But then if you say a 12-way mix is going to be beneficial for your soil, I then notice that some farmers would go out and get six grasses, I'm talking again about pastures, six grasses and six legumes, because it's really easy to get six legumes. There's all these different clovers that you can get, and you know, throw in alfalfa and sandpoint and whatever. And before you know it, it's easy to get six legumes. It's very easy to get six different grasses.

1:25:50 And I think I've got a 12-way mix, but they've actually only got two functional groups. So it could well be that someone else who just has four functional groups and four species, like a grass, a legume, and chicory and plantain for example, may do just as well. And it looks like the results that are coming out of the Smart Grass project and the Smart Sport project in Ireland tend to back that up, because they only do have four functional groups in there.

1:26:20 I'm sure there's advantages to having more species. So some of the dairy farmers for example who are putting in 20-way mixes and they've got all these pasture herbs in there, it's going to have to be beneficial, you would think, for animals to have that wide diversity, you know, of plants, because every plant is going to have different vitamins and minerals. Like, there's going to have to be some kind of incremental benefit from having more species in there. But I think the main benefit is going to come from four functional groups. And that's something that we've only come to realize, or perhaps I've only come to realize, in the last two years, 12 months to two years.

1:26:59 So some of my old videos, I mean, this is the problem with the internet these days. You can go back to a video that was made in 2010 or something like that. You know, that's 11 years old now. And there's probably nothing really fundamentally wrong with any of the information, but we have moved on. You'd hope, you know, like, even next week, hopefully we'll know more than we know this week. And the week after, we'll know more. So the more we're seeing, and the more diversity experiments that are being conducted around the world, and the more farmers are experimenting with these things, the more we're seeing is, 'Go, what, how can we distill the absolutely essential information out of this?' And the essential information seems to be, it's not so much about the number of species you have, but the number of diverse functional traits you have.

1:27:53 In other words, what's a functional trait? Like, and we want, in the literature they talk about asynchronous functional traits. In other words, plants that don't grow at the same time and have the same kind of root structure or photosynthetic pathway. Like, in the early days, you may remember, I'll go back to Gabe Brown again, talking about warm season, cool season grasses and broadleafs and grasses. Like that's what we thought was important. But in actual fact, you could have 12 species that fit within those categories and still only have two functional groups, because you may just have grasses and legumes. The chances are though, you're going to have some brassicas in there.

1:28:40 Because your cool season broad leaves are probably going to be brassicas, so you may have three functional groups. But just think how much further could you go by just throwing in another one. And that's why I think when we talk about things like flax or linseed, which is the same thing, which is in lenacie, a very different plant family to all of the others. Or something like well for celia in Virginia, a very different plant family to our grasses and our legumes. And we talk about the benefits we see putting something like flax into a companion crop mix. Is it because the flax is amazing? There is no doubt about it, has an incredible root system. But is it just the fact that flax is an amazing plant and it's non-competitive and it's a great companion? Or is it that flax is so different to everything else? It's in a completely different family. It's not like any other family that we're using. And it gives us that functional diversity. It's probably a mixture of both things. Flax is great, it's mycorrhizal, has an incredible root system. But it's also providing a lot of functional diversity. And that may be where the key to including things like flax and the cilia is. Are they exceptional plants in their own right, or is it that they are so different to everything else?

1:30:08 So in our companions, I would definitely be looking at just putting some really different things in there in our companion crops. Because you know, you can put things in there that won't be competitive with the cash crop. I mean, I'm sure we'll get to the stage where we can find companions for all of our cash crops. I know there's lots of other things that we've been thinking about, like interceding and all of that, that we'll be able to just grow companions in with cash crops with no problems whatsoever. They won't be competitive, they will actually be cooperative. And we will get higher yields.

1:30:40 Functional diversity is something it's going to be very important, I believe. We just probably don't know enough about it at the moment. So if I ever wanted to correct anything that I've said in the past, I would now correct that. You probably don't need, especially don't need 12 species if they're six of my grasses and six of them are legumes. That's not going to get you very far. You've only got two functional groups.

1:31:09 Okay, we are past seven, but I want to get to this last question here because I think it's important. And that is, what are some good soil biology or soil ecology books that you recommend for anyone who's wanting to learn more?

1:31:27 The top of my head I can't think of one. I'm sorry. Okay, I'll think of one for you. It's called our Soil Health Resource Guide, where Christine has written articles. We have lots of good information you can request one for free on our website.

1:31:44 You're right now, I agree. I was sort of thinking of a book, you know, by Chelsea Green or something or other like that. But yes, the Soil Health Resource Guide, I'll give it, you know, 20 out of 10. There you go. It's not technically a soil ecology book. But we got it, we got Christine's approval. So that's all we need.

1:32:06 Thank you so much. That was excellent, as always. And the presentation went smoothly, I thought it was great. So we've got one last session here that we're going to do next week. I do not remember what the title is off the top of my head. I know what the topic is. But you want to tell everybody what we're going to be talking about next week?

1:32:26 Yeah, it's something about cover crops and something about horticulture. But the emphasis was about carbon, I think it was. Cover crops for carbon storage in horticultural soils or something like that. And I will definitely be talking about carbon sequestration. But the more I look into this, into diversity and endophytes and all that sort of thing, and the huge plant protection benefits that we can get from having a diverse cover crop in the inter-row in a horticultural situation.

1:32:58 So one of the main things I'm going to talk about next week is how plants can actually access those microbes that are in the soil. So we've got soil living microbes that are internalized by plants and become endophytes. I think that's extraordinary. That something that's living in the soil is taken into the plant and becomes, and it's going to be nurtured by the plant because it's going to give the plant protection against pests and diseases. But the plant can't get those microbes to help it to protect itself if we have their interest.

1:33:35 So we need covered inter-rows for carbon storage, and we need diversity in that ground cover in the inter-row. Because we know microbial soil plant diversity is going to increase microbial diversity, is going to increase carbon storage. And that's what originally, like a month ago or so, I said I was going to talk about. And I still am. I'm also going to add to that, like how those perennial plants are going to be able to access the microbes that are growing underneath our annual cover crop that's in the interior. And actually internalize those microbes and use them for plant protection.

1:34:13 Well, there you go. The good news is, if you guys are on this webinar, I will automatically sign you up. But if there is somebody that you think would benefit from this next week's webinar, you can email me at Noah, that's N-O-A-H, at greencover.com. And I can send you a link that you can send your family, friends, anybody that would be interested. And I can get you the link to register for that. This webinar is recorded, so we'll have that uploaded on Thursday morning for you to share as well.

1:34:44 I think that about wraps us up for this evening. Thank you so much for joining us, and thank you, Christine, for your time. We really appreciate it, and hope you have a great rest your week.

1:34:56 Thank you very much, Noah. And again, it was a huge pleasure to be part of your webinar series today. I said I was going to send you two links. One was to the owner experiment, I think Keith found that one. Can you remember what the second one was? Was it something to do with the Irish research? Maloney's research? Yeah, it's fantastic. Absolutely fantastic research. So I'll do that now, and you'll be able to add that to the page.

1:35:24 Thank you very much, Noah. Great to work with you, as always. Very happy to know I ordered that book you recommend himself. We'll use it, Dale. Read it. Good. I want to hear of a dramatic improvement by next week. Okay, it looked like Arnold Schwarzenegger's younger days then. No, no, no, no, no. We just want you to have a mobile back. We want your back. That would be a great start. Yes, yes. And you can be eternally grateful to me.

1:36:02 Okay, Dale. Now you at least have to tell people what the book is. Otherwise, I will get emails saying I heard at the end of the webinar there was a book. I'll trim this part out anyway. But you might as well tell people what the book is. It's a book by Robin, R-O-B-I-N. Robin is a male. Robin McKenzie, Treat Your Own Back. If anyone has any problems with bulging discs, it is absolutely fantastic. I got it for six dollars and 39 cents on World of Books. Read it and use it.

1:36:40 What do you say? Well, I can't think of a better way to end the webinar. I'm just going to end it with fix your own back and have a great rest your week. Take care guys. Okay, bye.