Understanding the Role of Soil Microbes with Laura Decker
Summary
TLDRLaura Decker, from Prolific Earth Sciences, discusses the importance of soil microbes and their crucial role in sustainable agriculture. She explains how conventional farming practices using chemical fertilizers and pesticides have disrupted the symbiotic relationship between plants and microbes, leading to soil degradation. Decker emphasizes the need to rebuild a balanced microbial community by reducing chemical inputs and fostering conditions for microbes to thrive. This includes using cover crops, implementing microbial inputs, and adopting bio-stimulants that enhance soil structure and nutrient availability. By understanding the significance of a healthy soil microbiome, farmers can reduce input costs, increase crop resilience, and potentially earn carbon credits, making farming more profitable and environmentally sustainable.
Takeaways
- 🌱 Microbes have a symbiotic relationship with plants, feeding each other and contributing to soil health.
- 🚜 Conventional agriculture with chemical fertilizers and pesticides has disrupted the natural microbial communities in the soil.
- 💪 Healthy soil relies on diverse microbial communities for plant immunity, nutrient cycling, soil structure, and carbon sequestration.
- 🌳 Microbes help build soil structure by secreting sticky substances that bind soil particles together, creating pockets for air and water.
- 🍽️ Microbes create both fresh and stable soil organic carbon (food stores) for plants and themselves.
- 🌻 A balanced, diverse microbial community is key for optimal plant growth, immunity, and weed control.
- 🚫 Direct microbial inputs may not work if the soil conditions are not suitable for microbial growth.
- 🌏 Microbial communities can vary widely based on soil composition, climate, and region.
- 📈 Monitoring changes in microbial biomass over time is more important than the absolute number.
- 🔬 The microBIOMETER helps farmers and growers assess their soil microbial health and the impact of their practices.
Q & A
What is the main topic of this presentation?
-The main topic of this presentation is the importance of soil microbes and their role in agriculture, with a particular focus on how they contribute to soil health and plant growth.
What are the negative effects of conventional agriculture on soil microbes?
-The extensive use of chemical fertilizers, herbicides, and pesticides in conventional agriculture has led to a decline in soil microbe populations. The chemical fertilizers provide nutrients in a readily available form, reducing the symbiotic relationship between plants and microbes, and the herbicides and pesticides can directly harm the microbes.
How do microbes contribute to plant health and soil structure?
-Microbes provide immunity to plants against pathogens, help plants acquire essential nutrients and minerals, digest plant litter and convert it into soil organic carbon, communicate soil conditions to plants, and build soil structure through the secretion of sticky substances that bind soil particles together.
What is the relationship between root structure and microbes?
-Plant roots serve as a means of communication between plants and microbes. When plants are fed chemical fertilizers, they have a decreased need for microbes, leading to reduced root structure. A diminished root structure then creates a vicious cycle, as fewer roots mean less decomposition and less soil organic carbon for microbes to thrive.
What is the importance of microbial diversity in soil?
-Microbial diversity is crucial for a healthy soil ecosystem. Different microbes have different functions, and a diverse microbial community can provide a wider range of benefits to plants, including micronutrients, immune responses, and resilience to pathogens and environmental stresses.
How do microbes build soil structure?
-Microbes secrete a sticky substance called EPS (extracellular polymeric substances) that binds to soil particles, creating small cavities or "caves" around them. These caves can hold oxygen, water, and other microbes, forming soil aggregates. As microbes die, their bodies become soil organic carbon, further contributing to soil structure.
What is the difference between fresh and stable soil organic carbon?
-Fresh soil organic carbon is readily available for microbes and plants to consume, similar to food in a refrigerator. Stable soil organic carbon is more complex and needs to be broken down further, like food in a freezer that needs to be defrosted and cooked before it can be consumed.
What is the purpose of priming meals in soil?
-Priming meals, such as compostees or other inputs with sugars and microbes, can provide a burst of readily available food for soil microbes. However, if the existing soil cannot sustain microbial life, these microbes will eventually die off when the priming meal is consumed, leading to a temporary boost in microbial activity.
How can microbial inputs like mycorrhizal fungi or compostees affect soil microbial communities?
-The success of direct microbial inputs, such as mycorrhizal fungi or compostees, can vary. If introduced to soil that cannot support microbial life, the added microbes may not survive. However, research is ongoing to understand how microbial populations vary across different locations and how to effectively introduce beneficial microbes.
What is the purpose of the microBIOMETER product mentioned in the presentation?
-The microBIOMETER is a product developed by the presenter's company, Prolific Earth Sciences, that allows farmers and growers to test their soil microbial biomass in real-time, over time. This enables them to assess the impact of various practices and products on their soil microbiome and make informed decisions to improve soil health.
Outlines
🧫 Introduction to Soil Microbes and Their Importance
Laura Decker, an employee at Prolific Earth Sciences, introduces herself and explains the importance of microbes in soil. She discusses how conventional agriculture, with the use of chemical fertilizers, herbicides, and pesticides, has disrupted the symbiotic relationship between plants and microbes, leading to soil degradation. Microbes play a crucial role in providing nutrients, immunity, decomposition, and soil structure. A healthy soil relies heavily on a diverse microbial community.
🌱 Microbial Communities and Their Layered Interactions
Decker explains that microbial communities are extensive and layered, with each microbe having limited DNA and the ability to produce only one or two compounds. Microbes rely on each other's byproducts to thrive, creating a chain reaction where one microbe's growth enables another's. As the microbial community becomes healthier, it becomes more diverse, resilient, and beneficial to plants. A diverse microbial population is essential for providing various micronutrients, immune responses, and other benefits to plants.
🧪 Microbes and Soil Structure
Decker discusses how microbes play a crucial role in building soil structure by secreting a sticky substance called EPS, which binds soil particles together, creating aggregates and pockets for water, oxygen, and other microbes. This process helps prevent erosion, increases water-holding capacity, and improves soil resistance to drought. As soil structure improves, it becomes easier for microbes to thrive and contribute to further soil development. Decker emphasizes the importance of soil organic carbon, both fresh and stable, as a food source for microbes and plants during times of stress.
🌳 Building a Balanced Microbial Community
Decker acknowledges the difficulty in providing a simple solution for building a balanced microbial community, as it depends on factors like soil, climate, and crop type. The goal is to create optimal conditions for microbes to thrive by providing the right food and environment. Practices like cover cropping, where plants are grown continuously, help feed microbes and support the symbiotic relationship between plants and microbes. Decker discusses various types of inputs, including chemical fertilizers, microbial inputs, and biostimulants, and their effects on microbial communities.
🔍 Assessing Microbial Health and Diversity
Decker addresses questions about optimal microbial biomass and fungal-to-bacteria ratios, stating that it depends on factors like soil composition, pH, compaction, organic carbon stores, temperature, salts, crop history, and water availability. The important metric is not the absolute number but the change in microbial population over time, indicating whether practices are improving or harming the soil microbiome. Decker introduces Prolific Earth Sciences' microBIOMETER, a tool that allows farmers and growers to test microbial biomass in real-time and assess the impact of various inputs on their soil microbes.
Mindmap
Keywords
💡Microbes
💡Soil Structure
💡Symbiotic Relationship
💡Chemical Fertilizers
💡Soil Organic Carbon (SOC)
💡Microbial Diversity
💡Cover Crops
💡Microbial Inputs
💡Bio-stimulants
Highlights
Microbes and plants have a symbiotic relationship, where microbes feed plants and plants feed microbes.
Extensive use of chemical fertilizers, pesticides, and herbicides has reduced the growth of microbes in the soil.
Healthy soil is deeply reliant on the microbial community, which provides immunity to pathogens, minerals and nutrients, decomposition of plant litter, and builds soil structure.
Microbes help build soil structure, which increases water holding capacity, prevents erosion, and makes plants and soil resistant to drought.
Microbial communities are extensive and layered, with each microbe producing compounds that support the growth of other microbes in a chain reaction.
A diverse and resilient microbial community is essential, as microbes barter micronutrients and chemicals among themselves.
Microbes attach themselves to soil particles and secrete a sticky substance called EPS, which creates soil aggregates and holds oxygen and water, building soil structure.
Soil structure is important for mitigating drought risk, as it can hold more water.
Microbes make soil organic matter from plant material, which becomes fresh and stable carbon stores that are crucial for plant and microbial food security.
Building a balanced microbial community depends on creating optimal conditions for microbes to thrive, which varies by soil climate and crop.
Cover crops are important for keeping microbes healthy, as they allow plants and microbes to continue feeding and supporting each other.
Microbial inputs like mycorrhizal fungi and compostees have varying success, and direct microbial inputs may not work if the soil cannot support microbial life.
Bio-stimulants create environments that help microbes grow, perpetuating a system that reduces reliance on expensive chemical fertilizers.
The optimum microbial or fungal to bacteria ratio depends on various factors like soil composition, pH, compaction, organic carbon stores, temperature, salts, crop history, and water availability.
The microBIOMETER allows farmers and growers to test their microbial biomass in real-time to assess the impact of practices and products on their soil microbiome.
Transcripts
My name is is Laura Decker. I work
with a company called Prolific Earth Sciences,
and we make the microBIOMETER which
is an in-field test for soil microbes.
And Trevor asked me to come give
a quick little talk about the importance of microbes
and the role, a little bit more scientific
based, of microbes in the soil.
I think sometimes when we talk to people,
we sort of assume that everyone is on
the same page with microbes,
and understands fully what they do
and why they want them. So this is just
a quick
overview of
some of the important parts
of the soil microbe cycle.
Next slide.
So,
in conventional, what I call conventional
agriculture, which has been agriculture used
sort of traditionally in the United States
which uses perhaps
some irrigation, perhaps some chemical
fertilizers, herbicides and pesticides
and what we've been learning, as
the soil starts to degrade naturally,
is a lot of that is because the chemicals,
NPK, that we have been feeding
the crops, which have been incredibly
effective, essentially
in increasing yield, which has been a
wonderful thing... What it has done
is taken away the role of the microbes
in the soil. So plants and
microbes have a symbiotic relationship.
Microbes feed plants and plants
feed microbes. But plants,
like all of us, are a little bit lazy, and if
you do put down chemical fertilizers,
it's much more readily available to the plant.
So instead of... for them bartering
with the microbes, and working
that relationship, they will just eat up
the chemical fertilizers that
have been put down.
So really the effect of
the extensive use of chemical
fertilizers, and frankly pesticides
and herbicides, is that the microbes
have not been
growing the way they used to, or
in a system that's sort
of untouched by agriculture.
Next slide.
A healthy soil is deeply
reliant on the microbial community,
and I can't go into all of these, but I'll do a
couple of them today. One is
that microbes give
and provide immunity to pathogens
to plants. This is
a presentation in itself, how
microbes and plants communicate
the existence of pathogens,
and how microbes feed
plants immune
chemicals to help them with that. Plant
also gets the required
mineral and nutrients from microbes
that mine it from the soil, or create
it and trade it with the plant.
Microbes also digest the litter.
So, as the roots of plants
that are left in the soil start to decompose,
those microbes will eat those and decompose
them and turn them into soil organic
carbon, which we'll talk about later,
as an important part of
the food stores for microbes
and plants in the soil.
Microbes also feed information
to plants about the soil conditions.
Okay,
and more importantly, I think we'll
talk about this a lot more, is that microbes
help build soil structure. We know soil
structure is incredibly important for a lot
of different reasons.
It helps prevent erosion.
It increases the water holding
capacity
of soil. It makes plants and
soil resistant to drought,
and it also increases the oxygenation in
soil... erosion.
And then also,
and I'm not gonna hit on it now because
it's sort of controversial, a little hard,
but sequestering carbon is one of the things
that microbes can
help do. And I certainly hope
this is certainly...
there we go... something that could be
talked about later, that when we talk about making
farming more profitable, right,
we talk about reducing
input costs and also
hopefully we will, at some point, be talking
about farmers, not just
farming crops but farming carbon
to make farming
more lucrative.
Next slide.
So this is just a picture of a control
plant. You can see the roots down there...
that says, here's a control plant on the first
one. And then you can see the root structure
if the plant is fed chemical
phosphate, nitrogen, ammonium
and Potassium. And you can see
that really what happens is the plant
is like "Oh I have all the food I need,
I don't need microbes to help me." So
the roots are how the microbes
and the plant communicate. And so
there's a decreased root
structure.
Decreased root structure then creates
essentially a vicious cycle. If there's
fewer root structure,
roots also break up soil, aerate
it, do all that good stuff. But also roots
decompose in the soil, make soil organic
carbon which we'll talk about later.
Next slide.
One of the things to understand about
microbial communities is that they're
very extensive,
and they layer. A microbe
has very very little DNA.
So each microbe can only make
one or two compounds, ok? So,
and what we like to say, is that
if you have a... like this is a Petri
dish, I don't know if anyone has kids in school,
but they always do this, right? You take a clean
Petri dish and you put your hand on
it. The first thing that will happen
is one microbe will start to grow,
and it'll look like a certain color, and
then as that microbe grows, it
starts creating the enzyme,
the chemical, and the food that another microbe
needs. So that microbe will perhaps
have a spore there, but until
it gets woken up by another microbe,
it can't thrive. So there's
a chain reaction.
Bacteria A can't grow until
bacteria
have provided the food. So
as your microbial community
gets healthier, it gets more diverse
and bigger. So it's not like
you can just,
in one day, get the microbial community
back up, you have to build it layer
by layer. So just as the
plants and the microbes barter micronutrients
and chemicals,
so do microbes, okay. So microbes,
you need to have a diversity of microbes.
Now there are, I don't even know
if millions is the right word to use, but many,
many, many kinds of microbes. We
know almost nothing about them. We know
that some are good and some are bad,
but we don't quite know. And the other
thing we don't quite know, is how
do they vary across the globe and
in different areas? Right, so
that's one area that's getting kind of exciting
right now. But what we do know is the bigger
your microbial population becomes,
the more diverse it comes and
the more diverse it is, the more
resilient it is, and the healthier
it is. So
this is just sort of a primer on
why you want a large microbial
community, right? Not just because you want a lot
of the same microbes, but you want lots
of different microbes to provide
micronutrients and
different immune responses to your plant.
Next slide.
Soil structure. I think we talked a little
bit about this. This is kind of cool.
I think people, you can look at soil
and know if it has good soil structure or not,
right? You don't need to run any
fancy tests. But the way microbes
build soil structure is that microbes are
sort of running around in the soil.
and they get eaten by other
microbes by nematodes, by all kinds
of things. It's sort of a tough world
underground, these microbes.
So they attach themselves to soil particles
by secreting a sticky substance called
EPS, ok? And what
that does is make a little cave around
them, right?
That cave can hold oxygen and
water and other microbes and
soil debris. When the microbes
die, right, their bodies
become soil carbon, but the sticky
substance remains, okay, creating
soil aggregates and
soil carbon from their dead bodies
in it. Next.
So here's a little life cycle
of a soil aggregate. You could see on
the top left, they start forming,
right, a microbe will start secreting the substance,
it'll bind to soil particles.
It'll maybe have some roots going through
it or some old debris, maybe other
microbes will join them, then it'll be
stabilized, right? Will be this nice little
home. It's got a pocket for
a little bit of oxygen, a little bit of water.
And that's one of the things why soil
structure is so important for mitigating drought,
risks because you can hold a lot more water
if you have structure. And
then they disintegrate. These are... it's a very,
very fast cycle. Some microbes
reproduce every 15 minutes or so.
So there's a lot happening down there.
When they disintegrate, the sticky substance
is still there. But again, the bodies
of those microbes
become food for new microbes.
So again, it's just a virtuous
cycle as soil structure gets to get built,
it becomes easier to build it with
all those microbes.
Next slide.
Microbial food security.
So...
our carbon stores. So there's a lot
of talk about soil, organic carbon, both
fresh and soluble. Fresh,
I think about, is sort of the food in
your fridge, right? You can just grab it and eat it
and stable is like the stuff in your freezer,
right? You have to defrost it and cook it, okay?
So soil microbes
make soil organic matter
from plant material that's being broken
down and it becomes sort of fresh
and then it goes down, it becomes stable.
Ok.
That is incredibly important because
when soil and plants become stressed,
right, they'll eat up the fresh soil
organic matter, but they need additional stores
in your soil, which is why you
can't rebuild your soil structure
in a year. Right?
You need to work on those
stable stores
of carbon in your soil. This
is also gonna be the key to
hopefully getting growers
and farmers access to soil carbon
credits, right? So to be paid
to make the soil healthier to have
carbon sequestered will also
cut back on your input costs.
Right? And hopefully make
everything more profitable, which is ultimately
the objective.
Next slide.
This is just a funny picture of sort of a priming
meal. One of the things that we, we talk
about is that the effect of priming.
When you have soil that can't
sustain microbial life, right...
and you throw down what would essentially
be sort of an easy meal, right? The
equivalent would be feeding you a bowl of cereal,
right? You prime it. You can eat it right
away but the food is gone. So
sometimes compostees
can have this effect, right? Compostees
will have sugars in
it and microbes in it. You can put
it down
and it'll give you a burst of microbial
activity, right? Because there's microbes with
readily available food. But
over time those microbes
won't have anything to eat in the existing
soil and they will die. So when
we talk about building soil organic
matter, it's so that you have stores
of food for those microbes and
the plants. Next.
Building a balanced microbial community. I wish
I could tell you a super easy way to do it.
I can't, I'm actually not an agronomist.
We work on making the test.
But we will say it depends a lot on your
soil climate and your crop, okay?
When we talk about
healthy soil, the goal is to create optimal
conditions for microbes to thrive
in the soil. When your microbes
are thriving, your plants do
better both in terms of
growth, immunity,
and weed
control.
The microbial community can
thrive and survive itself, given the right
food and environments, okay.
Again, this is not a one size fits all,
this is sort of where the till,
no-till debate comes in. It's
not really meaningful at a high level,
but at a field
level, it might make a difference
for you to decide, is tilling the right thing
to do, selective tilling or no tilling.
And feeding the microbe will enable the
microbial community to start rebuilding
the cycle of healthy soil
and a healthy symbiosis
between plants and microbes.
One of the most important things
we talk about to keep microbes healthy
is cover crops right? Or to keep something
growing on the soil all the time
so that those plants and microbes can
continue to feed each
other, support each other and grow,
okay. Next.
So, this is just a discussion
of sort of very high level about the different
kinds of inputs there are. Chemical
fertilizers, we all know about them, MPK.
They're expensive and because of the activities
in Europe, are getting even more expensive
and perhaps even going to be quite
difficult to get. So,
and also the regulatory
and public pressure on reducing
chemical inputs and herbicides and
pesticides is getting pretty strong.
So, for a lot of different
reasons, we need to find
solutions that are more cost-effective,
and easier to do.
Certainly chemical fertilizers are effective
with judicial use. There's absolutely
no debate on that. Microbial
inputs is one other area that people are
working on. The example would be mycorrhizal
fungi, additive compostees...
people have
differing success with direct
microbial inputs. I think I covered
it before. If you put microbes
down on soil that can't support
microbial life, they will die.
Okay, so, you know, it's like
taking people and throwing them in the desert and
saying, good luck, they just can't do
that. They need to have water and food
and houses and things like that.
So often,
that doesn't work, sometimes
it does.
And the research is ongoing and unclear
about how much microbial populations vary
by location.
The other thing we know is that
microbes and bacteria and
fungi are all over the place.
We kind of want to say, like, it
literally falls from the sky. There
are microbes everywhere. You don't necessarily
have to worry about putting them into the soil,
although there certainly are times when
it makes sense, but you do need to
work on
making the soil a good home
for those microbes, okay.
And the third category, and it
uses different names, but we
call them for the most part bio stimulants
like Rhyzogreen®, right? These
are inputs that
create environments that microbes do
better in, okay. So they work because
they provide better conditions for microbes
to grow.
You need to, you need to make sure that they don't
just give you a 2-week boost in microbes
but they help microbes build
over time. And as the microbial
population will grow, the
plants will grow and you'll
have a community that is getting stronger
both in terms of above the ground, and below
the ground.
So a product that perpetuates a system
that reduces reliance on expensive
chemical fertilizers, right, as
the microbes grow and they can mine
the phosphorus and the nitrogen that's naturally
in the soil, and they can fix nitrogen
from the environment
and put it back into the soil, then
you will have a much more profitable and healthy
growth. Next slide.
What is the... this is the other question we get a lot, what's
the optimum microbial or fungal to
bacteria level? And our answers
to all these questions are, it depends! It's
really, really hard to know. There
are lots of different levels
of microbial biomass and fungal to bacteria
ratios for different kinds of soil. It depends
on where you are. Different soils have
different capacities. I live in the pacific
northwest.
Okay, even our most
terrible soil here is
teeming with life. We
have a lot of very temperate climate, we have
a lot of organic biomass in the
soil. And so that's naturally
the case. If you live in the desert,
right, it's gonna be a little bit different, even
if you've done the most
wonderful stewardship of your
land, you're not probably going to get the same levels
I get in my front yard.
So the limits and the
the things that determine how high your
microbial count can go is soil
composition.
The pH of the soil, both natural
and created, so depending on what you've been doing
to your soil, the compaction of
your soil. Again, some soil is more compact
than others, and then we've also done things
in the last
hundreds of years to create different
soil compactions.
How many stores of soil organic
carbon is in the soil? Both naturally
and created. Temperature and the season.
The salts and other chemicals that have been in the
soil, either naturally or things
that we've put down, either
on purpose or from residual
industry, your crop history and
your water availability. So the important
thing when you think about microbes, and I know Trevor
showed a bunch of numbers, is not necessarily
the number right? But it's the change
in the number. Are you taking the dial
and making your microbial population
stronger and more diverse so that
your plants can be healthier,
and mine naturally
the chemicals in the soil and the air.
Next.
And so I'll just tell you a little bit about
our company. We make the microBIOMETER.
We did it so that farmers and growers can
just go out in the field and test their microbial
biomass in real time over
time, to sort of see what's happening,
and to assess products
like Rhyzogreen®, and fertilizers,
to see what are they doing to my soil
microbes, right? Once I understand
how important it is for my crops to have
healthy soil microbiome. What
are my practices doing
to impact that? Am I making the situation
better or worse?
So that's just sort of why we're here
and why we talk about soil all
the time, because we get a lot of questions from
people,
about interpreting their results.
And that is it. I think I tried to go as quickly
as I can through some of that. We
have more content, you can do the next slide,
on our website and blogs and
videos that actually are a lot
more scientific based.
But I didn't want to bog and anyone down
with tables and charts,
but I'm happy to take any questions
that anyone would have.
Either here or
offline.
There has been a couple of questions
come in, and I wanted to address
them. One is,
when there's increased
nutrient value in the plants,
is it gonna attract insects?
And I'm gonna throw that to Laura.
I'll just put my 2 cents in
first. We have measured brix
on plants consistently
and we know, B-R-I-X,
that the higher the brix, the more
resilient
that plant is against weed
pressure, insect pressure and disease
pressure.
That is not something
we came up with. That is
just one of the principles...
the healthier the animal,
or the human, or the plant, the
more resistant and resilient
they are
to different pressures. But I'd like to throw that
to Laura. I would say exactly
the same thing. I mean that's sort of funny
to think that like a healthier you know,
crop would be more,
would would taste better to the bugs.
We do know that when you have healthier
plants, particularly that
are relying on microbes for their immunity,
they are naturally more immune.
But
I don't have any direct science
or done any studies for that. I just know
that the people who studied it have have
have got at least anecdotal and real
evidence that that's the case.
We've done one study. I mean
we did it inadvertently in North
Dakota where there was
a treated part of the field and a control,
and the control had much worse
Grasshopper invasion
versus the treated.
So I believe it.
The basics in terms of,
you know we work in animal health, have
done for 20 years, a healthy calf
or a healthy child.
They are naturally more resilient
to the disease pressure
and insect pressure,
weed pressure.
And I will also say that the more
plants, like people, are exposed
to pathogens, the healthier their immune
system is, so if you have a system that
is sterile,
then the plants don't have any natural
immunity and anything that comes by
will be much more virulent than it would
if you know, just like kids in day
care. Right? They have higher
immune systems.
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