Soil Microbiom and Trees

Talking Trees with Lillian Jadd . Welcome to Talking Trees , your daily journey into the intricate connections between nature and our well-being . In today's episode , we explore the concept of soil health within the broader One Health framework , highlighting the interdependence of human , animal , plant and environmental health .

Hey everyone and welcome to a deep dive into a world that's pretty much invisible but totally essential for the work that we do as arborists .

You got it . We're talking about the soil microbiome .

Right , the soil microbiome , all those billions and billions of tiny organisms living in the soil .

And I mean it when I say billions .

I bet you know I've been looking at some research papers lately on this topic soil microbiomes and one health Banerjee and van der Heiden . That was from 2022 , and also the concept and future prospects of soil health by Lehman and some others from 2020 .

Oh yeah , those are really interesting papers .

They are . They really highlight just how complex and important this whole world beneath our feet is .

Yeah , and they connect it to everything else too . You know , plant health , animal health , even human health . It's all connected , it's all part of what they call One Health .

Right One Health . So before we get too far ahead of ourselves , can you give us a little bit of a picture of just how much life is actually down there in the soil ?

OK , so imagine this All right the soil holds the largest amount of global biomass , except for plants , of course .

Of course .

So besides plants , soil has the most and bacteria are the most abundant , then fungi and archaea .

More than animals , oh yeah , way more .

The total number of microorganisms in a soil is larger than the biomass of all animals on earth .

Wow , that's amazing . So we're talking about like a whole universe under our feet , exactly . So how does all of this microscopic metropolis affect the trees that we work with every day ?

Well , soil microorganisms are basically essential for nutrient cycling . I mean they provide trees with 18 out of the 29 essential elements that they need to grow .

So it's not just about giving a tree the right fertilizer .

Nope , it's much more complex than that .

We have to think about the health of this entire community underground .

You got it . It's like an ecosystem .

An ecosystem , okay . So what about the rhizosphere ? I know that's important .

Oh yeah , the rhizosphere is super important An area right around the roots of a tree . It's just teeming with microbial activity , all kinds of bacteria and fungi interacting with those roots in all kinds of ways that we're still figuring out .

So you mentioned bacteria . What are some of the things that different bacteria do in this rhizosphere ecosystem ?

Well , take rhizobium bacteria , for example . They've got this symbiotic relationship with certain trees , where they convert atmospheric nitrogen into a form that the trees can actually use . It's like a natural fertilizer factory right there in the soil .

Wow , that's pretty cool .

It is , and then you've got fungi too . Fungi play a big role , especially

So it's like they're expanding the tree's feeding zone .

You could say that and in return the tree provides the fungi with sugars from a photosynthesis . So it's a win-win .

Mutually beneficial . Millions of years of evolution .

Yeah , it's pretty amazing . So are there specific types of mycorrhizae that are better for certain trees ?

That's a good question , you know , because I know there are different types of mycorrhizae .

Right . Well , like , for example , you have ectomycorrhizae . Those are commonly found on trees like pines and oaks and birches . They form this sheath around the root tips and their hyphae extend out into the soil .

It's creating a huge network , exactly .

And then you've got arbuscular mycorrhizae . Those are found on a lot of different trees , like maples and ash and fruit trees . They actually penetrate the root cells . They form these structures called arbuscules . Arbuscules , okay , and they actually penetrate the root cells .

They form these structures called arbuscules Arbuscules . Okay , and that's where the nutrient exchange happens . Wow , it seems like knowing the types of mycorrhizae that are associated with different tree species could really help us make better decisions about planting and care Absolutely .

The more you understand about these relationships , the better you can work with nature . Instead of against it Right it's about seeing soil as a living ecosystem , not just some dirt .

Yeah , and a healthy ecosystem is a resilient ecosystem .

Exactly which brings us to disease . Suppressive soils .

Disease suppressive soils . What are those ?

These are soils that have a community of microorganisms that are really good at keeping pathogens under control .

So they can actually prevent soil borne diseases or at least reduce their impact .

And get this . This ability to suppress diseases can last for over 40 years , even when pathogens are present .

That is incredible .

You could say that it's like a microclimatic army protecting your trees .

This whole soil microbiome is like a superpower .

It is . It's a superpower .

But I'm guessing there are things that we do that can mess it up .

Unfortunately , yes , some of the practices that are common in arboriculture can actually harm the very organisms that we're trying to protect .

Like what .

Well , things like excessive tillage and the use of synthetic pesticides can have a negative impact on the diversity and function of the soil microbiome .

So things that we think are helping could actually be hurting .

It's possible . And then there's also the issue of antimicrobial resistance .

Antimicrobial resistance .

Yeah , you know where the overuse of antibiotics in livestock can lead to resistant bacteria .

And that affects the soil .

Those resistant bacteria can end up in the soil and then you've got soil-dwelling mice that can pick up those microorganisms from the soil and then farm animals graze and they ingest soil .

Ingest soil .

Yeah , they eat it and it contributes to their rumen , microbiome .

Rumen microbiome what's that ?

It's the first compartment of a cow's stomach . It's full of microorganisms that help break down plant material .

Oh , okay .

And it's estimated that up to 3% of a cow's rumen microbiome can come from ingested soil .

So even a cow's digestion depends on healthy soil .

It seems so Wow it's all connected . It is , and just like those practices can affect soil health and tree health , they can also affect livestock health .

It all comes back to one health , doesn't it ?

Exactly , it's all part of the same web , so we're part of this web too , right ? Absolutely , we're connected to the soil through the food we eat and we're exposed to soil microorganisms through dust and even geophagy .

Geophagy what's ?

that that's the practice of eating soil or clay . It's more common than you might think , especially in certain cultures .

Interesting . So the health of the soil is directly connected to our own health . It is even in ways that we might not realize . We've covered a lot of ground here , this first part , from the abundance of life in the soil to the connections between soil microbes , trees , animals and even ourselves .

I think the most important takeaway is that soil is alive . It's not just dirt , it's an ecosystem , and it plays a vital role in the health of everything from the trees we care for to the food we eat , and as arborists , we have a responsibility to understand and protect this hidden world .

It's like we've been given a glimpse into this secret world .

Exactly .

And now we have a chance to become allies with the organisms that live there .

By working with them instead of against them .

Exactly , and by doing that we can improve the health of our trees and contribute to a healthier planet for everyone .

That's the goal , and now I want to learn more about how what we do as arboriculture and land management in general can actually unintentionally harm the soil

Right , we were talking about excessive tillage and synthetic pesticides earlier .

Exactly .

Can you talk a bit more about how those practices actually disrupt the balance of the soil microbiome ?

Sure . So tillage , especially deep tillage , can be incredibly disruptive . I mean , you're essentially like bulldozing a forest , you know . Yeah , you're uprooting trees , you're destroying habitats , you're scattering all the inhabitants , right , and it's kind of the same thing with tillage .

So we're basically destroying the home of all these beneficial microbes .

Yeah , you could say that .

What about synthetic pesticides ? How do they affect the soil ecosystem ?

Well , you know , pesticides are designed to target specific pests , but they often have unintended consequences . Right , they can also harm beneficial microbes , which can lead to a decline in biodiversity and overall soil health .

So it's like we're using a sledgehammer when what we really need is a scalpel .

Yeah , that's a good analogy .

So we need to be a lot more mindful about our approach . What are some things that we can do differently ? What are some alternative practices that we can use that will actually promote a healthy soil microbiome ?

Well , one of the most important things is reducing or even eliminating tillage . Okay , whenever possible .

Less killage .

Yeah , minimizing soil disturbance allows those microbial communities to thrive and it helps to maintain the soil structure .

Right , less disturbance , happier microbes .

Exactly . And then another really valuable tool is incorporating organic amendments .

Like what ? What kind of organic amendments are we talking about ?

Things like compost , biochar , well-composted animal manure these can really work wonders for your soil .

How do they actually help the soil microbiome ?

Well , they introduce a lot of diverse organic matter , which is like food for the microbes , and it improves the overall soil structure .

So it's like having a party and you're bringing all the good food .

Exactly the more diverse the food , the better the party .

Okay , so less disruption , more diversity . I'm seeing a pattern here . What about the types of trees that we plant ? Can that affect soil health ?

Oh , absolutely . Native trees have co-evolved with the soil microbes in their region Right and they form these complex relationships that benefit both the tree and the soil .

So when we choose native species we're kind of supporting those established partnerships .

Exactly . It's like choosing a dance partner who already knows the steps .

Okay , I like that analogy . So we should really be thinking about what the soil wants when we're selecting trees .

Yeah , it's all about recognizing that a tree is not just an individual . It's part of a whole web of interactions .

Right , it's part of an ecosystem .

Exactly , and by choosing trees that fit well with that existing soil ecosystem , we're really setting them up for success .

Okay , so we've talked a lot about building up the soil's natural defenses , but what about situations where we're already facing challenges like soil compaction or disease pressure ? How can we address those issues while still making sure that we're not harming the soil ?

Well , even in those cases we can use soil health focused solutions . So for compaction you can use aeration techniques to help improve drainage and oxygen flow .

OK .

That creates a more hospitable environment for those beneficial microbes .

So it's like we're giving the soil the tools it needs to heal itself .

Exactly , and when it comes to disease , remember those disease suppressive soils we talked about .

Yeah .

Well , by fostering a diverse and thriving microbial community , we can create conditions that naturally suppress pathogens .

How do we actually do that in a practical sense though ?

Well , diversity is key , so incorporating

It's kind of like building a diverse community . It is .

It is when everyone has different strengths and skills the community as a whole is stronger and more adaptable .

That's a great point . So instead of relying on chemical treatments to combat diseases , we can actually empower the soil to fight back naturally .

Exactly , and there are even biocontrol products available that introduce specific beneficial microbes to help combat certain pathogens .

Oh , wow . So it's like we're recruiting a specialized team of microbes .

That's a good way to think about it .

It all ties back to that one health concept , doesn't it ?

It does the health of the soil , the plants , the animals and us humans . It's all interconnected . When we take care of the plants , the animals and us humans , it's all interconnected .

When we take care of the soil , we're taking care of everything .

That's right . So , as we're wrapping up here , what are some of the key takeaways that you want our listeners to remember ?

Yeah , what are the big things ?

Well , first of all , I want everyone to remember that soil is alive , you know , it's not just dirt , it's an ecosystem , and it's an ecosystem that supports the health of our trees and the health of our planet . So by shifting our perspective , you know , instead of just treating individual trees , let's start thinking about nurturing that entire soil ecosystem .

The whole web . The whole web and by doing that we can unlock all kinds of benefits . You know , we can reduce our reliance on chemical inputs , we can make our trees more resilient and we can contribute to a healthier environment for everyone .

That's right . So let's go out there and let's do it .

This deep dive has been truly inspiring .

It has .

It feels like we've not only learned a lot , we've also been reminded of just how important it is to care for this world beneath our feet .

And that's what it's all about , you know empowering arborists to become champions for soil health . So keep learning , keep experimenting and keep sharing your knowledge with others , because together we can create a future where healthy soil is the foundation for thriving trees and a vibrant planet .

That's a great message to end on . Thank you so much for joining us on this deep

Thank you for joining us on today's exploration of soil health and its vital connection to the One Health Framework . We've delved into the remarkable role of soil microbiomes in sustaining ecosystems and discussed how robust soil health underpins sustainability and human well-being .