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hello everybody this is our lecture on
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soil organic matter and right here on
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the title page I just want you guys to
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notice it says adapted from the
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University of Minnesota Extension pub
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publication called soil organic matter
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does matter and so I've also put that
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publication in as a reading on the in
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the module so if you have time and you
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want more information or you want more
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detailed information or you have like a
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question and you're not sure I would say
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read that publication and then let me
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know if you still have any questions
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after this lecture or after reading that
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publication so let's start with kind of
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the easy stuff what is soil organic
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matter so the kind of textbook
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definition of soil organic matter would
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be the organic fraction of the soil that
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includes plant animal and microbial
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residues in various stages of
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decomposition biomass of soil
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microorganisms and substances produced
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by plant roots and other soil organisms
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and you guys know I'm not huge fans of
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big long complicated definitions so how
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about just the material and soil derived
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from other living organisms this is
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mostly gonna come from plant tissue but
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that's what we're talking about so when
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we say this plant animal microbial
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residues in various stages of
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decomposition its material in soil
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derived other living organisms and it
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can be in various stages of
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decomposition so where does it come from
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so all organic matter comes from plant
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tissue when you think about it so even
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if it's like let's say it's some sort of
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a dead animal or or feces from a dead
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animal what is that animal eating
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they're either eating plant tissue or
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they're eating another animal the was
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that other animal eating is probably
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plant tissue so the idea is that all
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organic matter really comes from from
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plant tissue and then the microbes in
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the soil decompose organic matter
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to sustain their life process that's how
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they that's how they get energy that's
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how they tell they sustain life so in
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this little graphic that I put in here
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so step one the plant matters turned
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into soil and so then we have nutrients
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and carbon then you have soil microbes
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releasing stored nutrients from the
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plant matter and making them the
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nutrients available then the nutrients
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are released by the microbes and taken
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up by the plants and then the microbes
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will generate more organic matter and
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then continue the cycle of building and
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storing nutrients in the soil and so
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that's how this kind of cycle just keeps
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going of microbes eating and and
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creating soil organic matter so what is
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soil organic carbon because some people
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use those terms similarly well soil
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organic carbon makes up the majority of
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soil organic matter so about 58% so
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almost 60% of soil organic matter is
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soil organic carbon so that's why you'll
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see them kind of used interchangeably
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the rest of soil organic matter is made
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of hydrogen oxygen nitrogen and
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phosphorus if you wanted if you saw
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numbers for soil carbon at soil organic
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carbon as opposed to soil organic matter
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you can just multiply your soil organic
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carbon number by 1.7 and that would be
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what your soil organic matter is until
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on the right-hand side here I've got a
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little diagram showing just the idea of
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kind of a simplified carbon cycle of the
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idea of the carbon going into the plant
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via photosynthesis and then the roots
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releasing some carbon compounds and then
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that's how we get carbon into the soil
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because soil holds carbon well and then
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organic matter and through decomposition
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carbon is released back into the
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atmosphere in the United States this is
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kind of what it looks like in terms of
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soil organic carbon so you can see high
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amounts of carbon in
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the kind of Great Lakes area down at the
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Gulf of Mexico and then like the East
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Coast and the Pacific Northwest those
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are kind of our higher areas in terms of
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organic carbon so levels of organic
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matter so when we're talking about the
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majority of mineral soils they'll have
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usually somewhere between trace amounts
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so not zero but a little bit above 0 to
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20% soil organic matter in the mineral
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soil if they have greater than 20%
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organic matter and it goes to a depth of
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16 inches that's what's called peat or
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muck and there's a picture of peat or
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muck on the right-hand side there and
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those would fall into the soil order
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histah cells there's 12 soil orders and
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histah soles is one of them and histah
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cells have a high organic matter content
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and no permafrost because these are in
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cold cold much colder areas they're
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usually saturated year-round but a few
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are freely drained and they are commonly
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called bogs Moors pits or MUX because
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you can see what the soil looks like and
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if that soil is wet it's gonna be pretty
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pretty mucky pista Sol's form in
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decomposed plant remains that accumulate
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in water forests litter or moss faster
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than they decay these soils are drained
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in exposed to air microbial
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decomposition is accelerated and the
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soils may subside dramatically histah
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cells make up about 1% of the world's
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ice-free land surface so not a whole lot
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of area is covered by this sort of soil
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that's really high in organic matter so
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most of the soils you're gonna get
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somewhere between 0 and 20 percent of
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the soil sets of the organic matter in
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those soils but in these specific Kista
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Sol's these peat or mucks you're gonna
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have more than 20% so we've talked
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before about the idea of the O layer and
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the o layer being the organic layer and
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so how how do we define an organic layer
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as you know like how is an organic layer
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or no layer different from the topsoil
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the a layer and the the difference is
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that the to be and a layer it's got to
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have greater than 20% soil organic
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carbon by the weight of the soil and so
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that's that's the idea if it's got
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greater than 20% it's going to be an O
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layer but then you also see in this
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graphic on the right you see those
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different little lowercase letters and
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so those are sub layers and the sub
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layers the three that we'll talk about
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are the oh I the Oh II and the Oh a so
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oh I is slightly decomposed you can
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still identify the plant and animal
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material an OE layer is inter
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intermediately decomposed you can kind
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of identify some plant parts a know a
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layer is highly decomposed you can't
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identify the original source of the
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material and so it's so looking at this
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picture on the right there's an OE layer
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so I'm assuming if we could get closer
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up on that we'd be able to see some sort
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of maybe plant roots or or twigs or
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something that's that's an obvious plant
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part whereas in those Oh a layers we're
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probably not going to be able to
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distinguish anything or really see and
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know exactly where it came from so when
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we try and look at the the
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classifications of organic matter it's
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important to remember that not all
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organic matter is created equal
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so a good example is like in the animal
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carcass versus a large log that log
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there's gonna be different chemicals
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between the carcass and the log there's
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going to be definitely different
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decomposition rates may be certainly
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between like I think the paper gives the
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example of a mouse carcass versus a
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large log on the ground and that log is
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going to take a long time to decompose
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that mouse carcass is gonna decompose
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very quickly but there's a lot more
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probably for the soil or a lot more to
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be gained in organic and that large log
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than there is in that little mouse
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carcass and so it's it's a
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according to just kind of remember that
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it's not all the same but we do classify
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soil into basically - or soil organic
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matter into two main categories and so
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those two categories are active and
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stable and so active organic matter
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that's the portion of organic matter
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where it's actually decomposing so the
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idea that it's that it's active like
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it's actively decomposed so it's not
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it's not it hasn't finished decomposing
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it's still working its way where you can
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still see some of it so if we were
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talking about this in a in the old layer
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this would be an O I or an OE because we
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can still see some of the stuff that it
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came from we could still see what the
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what the material was before it it's
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just for ganic matters this this type of
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organic matter really fuels microbial
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activity because you get a lot of the
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release of the nutrients into the soil
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because this the active organic matter
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is easy for microbes to digest and use
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for their metabolism so they're able to
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eat it and give energy and then want to
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keep working fresh crop residues a
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really good source of acts of organic
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matter active organic matter contains
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sugars oils cellulose and proteins so
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those are excellent sources of energies
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and energy and nutrients for soil
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organisms and this can really change
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growing season the growing season
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because it's definitely not always the
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same amount of active organic matter
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every single year your stable organic
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matter that's that's your organic matter
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that's already decomposed so that would
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be that Oh a
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[Music]
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designation where you can't really
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recognize what it came from it's it's
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just kind of organic matter this makes
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up the majority of soil organic matter
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so anywhere between 60 to 90 percent of
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the total so you're active organic
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matter is going to be anywhere between
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40
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to 10% of your soil organic matter
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whereas your stable organic matters can
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be anywhere between 60 to 90 percent of
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the total as soil organisms digest and
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decompose the material several things
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are going to happen that the chemistry
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of the organic matter is going to be
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modified and the nutrients are going to
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be removed as the microbes decompose the
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material and the organic matter is gonna
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stick to soil particles which is going
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to become a really important idea the
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big thing is that state stable organic
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matter accumulates when active microbes
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continually are decomposing organic
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matter so when they are continually
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decomposing organic matter you can just
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kind of start building up organic matter
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and building up organic matter and
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building it up and building it up and
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building it up and that's that's when
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everything's going good we're going to
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talk about that in in depth a little bit
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more later on as to why there's when
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that's going good it's good it's but
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when it's not going good it's actually
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pretty bad for the soil so here is the
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the cycle of organic matter where you
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start off with fresh residues or what we
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call kind of plant material and all that
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stuff that comes from soil organisms so
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something dies whether it's the plant or
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an animal or its poop or any of those
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things so within days you're gonna get
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some release of co2 and and some of it
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going back into soil organisms within
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months the same thing within years the
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same thing but after years you're gonna
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start to see organic matter get
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protection and aggregates which we'll
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talk about in in the next slide and then
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after decades they start getting fixed
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to soil particles so they actually stick
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to soil particles and that's where we'll
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go from the active organic matter where
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it's it's decomposing to the stable
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organic matter where it's completely
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decomposed and all you can see is
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organic matter
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or actually I guess it's it's the
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aggregates is another slide but we'll
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get there
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houmous we talked about you miss in
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terms of organic matter humans is what
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they used to think stable organic matter
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was but now it's it's a major form of
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organic matter in the soil but stable
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organic matter comes from my cold real
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microbe really derived complex our
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microbial microbial ease derived
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products that can be simple or complex
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and so houmous is still used and
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sometimes you'll see people talking
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interchangeably with stable organic
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matter and humans but really humans is a
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complex table pool of organic matter but
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it's not saying the same thing as stable
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organic matter now we get to aggregate
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and aggregation so as soil particles
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stick and bind together they form
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aggregates active and stable organic
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matter can be trapped in these
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aggregates so if we look at the picture
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on the Left those kind of the when the
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soil binds together like that
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that's aggregation so when this happens
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though the soil particles are going to
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act like armor and protect the organic
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matter from decomposers which is great
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because that's how we get and go from
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this active organic matter it's a stable
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organic matter and we get stable organic
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matter once we have that to then start
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building up because it's protected from
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the decomposers and so soil organic
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matter accumulates during long periods
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of time like we just showed in the cycle
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from years to decades to centuries and
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the majority of soil organic matter is a
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result of decomposition and aggregation
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that has occurred during a long period
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of time and what usually that's when
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we're talking about you know decades to
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centuries and even longer healthy soil
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has a mix of active and stable organic
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matter and a steady supply of organic
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inputs such as crop residues and manure
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will help build and maintain
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stable organic matter pools and provide
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a wide array of benefits to the soil so
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the the active and stable organic matter
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getting trapped in these aggregates may
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sound almost like a bad thing but really
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it's fantastic for them because they get
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protection from decomposers and this is
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how we start really building up organic
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matter in the soil and so and that's
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something we want because we know that's
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how the plants get their nutrients so
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what are some of the benefits of soil
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organic matter we're going to go over
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six benefits we're gonna go over water
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retention and drainage soil structure
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nutrient cycling and retention cation
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exchange capacity microbial diversity
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and resiliency in crop yield in terms of
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water retention and drainage soil
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organic matter increases the ability of
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a soil to receive and hold more water so
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the particulate organic matter in soil
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serves as lightweight low-density
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bulking agent so basically think of a
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sponge and so if if this particulate
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organic matter acts like a sponge it's
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gonna help the soil create and maintain
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large pore spaces that allows water to
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infiltrate and drain and and also small
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pore spaces that the water can hold on
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to so basically imagine sticking a
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sponge that into your soil or letting a
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spongy material get into your soil
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that's going to bring in water it's
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gonna hold water and it's going to
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basically swell up and just keep water
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in there so soil organic matter because
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of the way it is being lightweight and
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low density it just has this great
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ability to just take in water and hold
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on to it which we know especially for
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sandy soils or clay soils those can be
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kind of an issue so definitely something
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that we would want to have in our soil
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definitely a benefit in terms of our
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soil structure we talked about this
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before this idea of the aggregation
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active organic matter
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specifically though forms sticky
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substances that help soil particles hold
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together so that helps soil develop and
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maintain that aggregate structure but
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doing this also feeds the microbes that
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help them grow and metabolize so in
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terms of soil structure the physical
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benefits better aeration so better the
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pores are open to where air can come in
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and out very easily better friability so
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the idea of the soil being able to come
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apart easier but not not to where it's
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just falling apart but that a can
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it's got like a plastic nature to it
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it's it can be moved and shaped easier
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less crusting so it doesn't get hard it
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gets it can be kind of softer it doesn't
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get really that hard type of soil that
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we see a lot when we think about
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compaction issues the way soil can get
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can get really hard and kind of loses
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that moisture uses the aeration and the
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moisture in the soil and then better
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water infiltration drainage and
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retention the biological benefits from
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having organic matter in there is that
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there's now a home for microbes worms
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and insects so we get the whole soil
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food web started and then we also it
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helps that that not only in providing
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that home for those species but then
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that allows those species to do what
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they do in terms of building up more
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organic matter and bringing in and
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working their way through the soil food
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web and creating that whole fertile
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ecosystem that that we want the other
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biological benefit is food storage
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because of the way organic matter is
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structured it's going to be a slow
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release of food for the microbes so it's
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going to shoot the microbes around if
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it's healthy organic matter and let them
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get some food but then have this kind of
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consistent source of food
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nutrient cycling and retention so active
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organic matter is full of fresh
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accessible nutrients so as the soil
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organisms break down and decompose soil
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organic matter the nutrients will be
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consumed by the soil organisms and then
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released into the soil solution so
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remember we're a soil solution is just
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we're talking about water and soil
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mixing together just like we did in lab
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we just took when we were testing our
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water we just put a little bit of soil
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in there put some water in there or
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sorry when we're testing our pH put a
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little soil in there put our little
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water in there and then we made a little
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soil solution that's what's happening in
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the soil as the water and the water and
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the air get in the pores they're
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creating that soil solution and so the
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nutrients basically get loosened up and
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get put into the soil solution and then
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the organisms will be able to get them
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for their from there also because
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they're put into that soil solution
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they're free for uptake by plants and
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other organisms or they can be lost to
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leaching or volatilization meaning that
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sometimes they don't get picked up and
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they just kind of disappear they get
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leached down farther down into the soil
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or they volatilize and work their way
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back into other inorganic forms and so
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as long as active organic matter is
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decomposing it'll provide the slow and
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steady supply of nutrients into the soil
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solution which is absolutely what we
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want because that's that cycling of
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nutrients and match the fertile soil
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that we're looking for cation exchange
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capacity which is something we talked
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about before the idea of the plant for a
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plant to be able to get nutrients the
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way that they're the nutrients are
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available is as an ion and the cation is
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a positive charged ion so the exchange
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capacity of the cation exchange capacity
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is just looking at how easily can these
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cations go from the plants to the soil
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and so soil organic matter provides
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between 20 and 80 percent of the cation
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exchange capacity and
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mineral soils so there are really a
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driver of this exchange of this exchange
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of ions in the soil and in general the
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higher the organic matter content in the
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soil the higher the cation exchange
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capacity and the more likely the soil is
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actually going to retain nutrients and
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be healthy and fertile and have
00:22:31
nutrients available a higher cation
00:22:35
exchange capacity also allows the soil
00:22:37
to be more resistant to rapid and large
00:22:39
changes and protects nutrient
00:22:42
availability and health in the soil so
00:22:44
remember with pH we know that you have
00:22:48
to you have to do things like adding
00:22:52
fertilizers or trying to reduce acidity
00:22:55
if your soil doesn't fall within that
00:22:58
really nice six and a half to seven and
00:23:00
a half pH range where we we know plants
00:23:04
do best because it's the best for it's
00:23:07
ideal for plant growth and so you know
00:23:11
if you have a soil and you finally get
00:23:13
it into that that proper range or the
00:23:17
soils already in that proper pH range
00:23:19
having a really high cation exchange
00:23:23
capacity really makes it easier for that
00:23:25
soil to stay in that range for longer
00:23:28
and resist changes based on something
00:23:32
like you know having a drought or I'm
00:23:36
dealing with farming or having something
00:23:38
where it might change the the pH of the
00:23:43
soil it's it's more likely to be more
00:23:46
resistant to that change if it's got
00:23:47
that higher cation exchange capacity in
00:23:50
so having more organic matter is gonna
00:23:53
make that easier in terms of microbial
00:23:58
diversity and resiliency soil microbes
00:24:01
are important for driving nutrient
00:24:03
cycles and influencing the availability
00:24:04
of the nutrients to the plant organic
00:24:08
matter provides a source of nutrients
00:24:09
and energy to the microbes so that in
00:24:12
soil organic matter is important for
00:24:15
creating and maintaining soil microbial
00:24:17
habitats so not only is the organic
00:24:20
matter giving nutrients and enemy2
00:24:23
nutrients and energy
00:24:24
to the microbes it's also creating and
00:24:27
maintaining the habitat and so if we
00:24:30
want to have a lots of microbial
00:24:32
diversity we're going to need a variety
00:24:33
of habitat conditions so soil organic
00:24:37
matter is gonna maintain these aerobic
00:24:39
and anaerobic conditions wet in dry
00:24:42
conditions in the soil nutrient rich in
00:24:44
nutrient conditions and large and small
00:24:47
pore spaces and it's going to help
00:24:48
maintain these conditions in the soil so
00:24:50
that it can have lots of microbes and
00:24:53
have this kind of resiliency organic
00:24:56
matter helps create a mix of these
00:24:57
conditions and a variety of homes to
00:25:00
support the diversity that we rely on
00:25:02
for soil function and if you're saying
00:25:04
well how does it create these different
00:25:06
conditions how does it create this
00:25:08
diversity remember it that among all the
00:25:14
different types of soil or layers of
00:25:17
soil organic matter is a layer soil
00:25:20
that's under constant change all the
00:25:22
time it's not going to be the same
00:25:24
because it's having the microbes
00:25:28
decomposing constantly and having fungus
00:25:31
and mycelia
00:25:32
doing some decomposition and it's always
00:25:36
kind of in the state of changes and and
00:25:39
this fluctuation so it can create it can
00:25:42
have large and small pore spaces and
00:25:44
nutrient rich and nutrient ditions and
00:25:46
web and dry conditions and aerobic and
00:25:48
anaerobic condition because it's always
00:25:50
changing there's always there's never a
00:25:53
consistent amount of organic matter
00:25:55
because it's always in flux with that
00:25:58
idea of active organic matter where it's
00:26:00
going through the decomposition phase
00:26:02
plus you also have the stable organic
00:26:05
matter where that's already gone through
00:26:07
that phase and so that mixing of those
00:26:10
two things plus the idea that you're
00:26:12
you're going through that constant
00:26:13
change allows for you to have that
00:26:16
variety of habitat conditions which then
00:26:18
allows for you to have species diversity
00:26:20
in the soil and then our last benefit is
00:26:26
crop yield and crop yield the big thing
00:26:29
with that is it's only up to a certain
00:26:31
point that organic matter really helps
00:26:35
out with yield but the
00:26:38
the real thing to think about is that if
00:26:40
organic matter is already helping with
00:26:42
productivity and structure and soil
00:26:45
health then it's definitely probably
00:26:48
gonna help with with the yield that you
00:26:50
get from your crop and the idea of
00:26:53
having more organic matter is definitely
00:26:55
better than having less organic matter
00:26:58
it just might be that there's a certain
00:26:59
point and get to where you have enough
00:27:01
organic matter but definitely you would
00:27:05
notice a difference if you didn't have
00:27:06
enough we're getting matter for your
00:27:09
crop so how do you build soil organic
00:27:16
matter well that's the idea of the
00:27:19
microbes and the Oregon and the organic
00:27:22
matter coming together and being really
00:27:25
important for productivity and health of
00:27:27
the soil so for the microbes to grow and
00:27:30
do their many jobs and they're the
00:27:32
drivers of the the soil ecosystem
00:27:36
they're gonna need food a place to live
00:27:40
and then the freedom from drastic
00:27:43
physical and chemical disturbances so
00:27:45
basically almost like any of us they
00:27:49
they want they want food so they have
00:27:51
energy to work they want a house so they
00:27:54
don't have to worry about where they're
00:27:55
gonna live or what's gonna happen and
00:27:57
they don't want to be bothered they want
00:28:00
to just have the freedom that do what
00:28:01
they do and if the soil and soil organic
00:28:04
matter can provide those three things
00:28:06
for the microbes they will just go nuts
00:28:08
and be building building organic matter
00:28:12
these same characteristics provide
00:28:14
conditions for increasing soil organic
00:28:17
matter as well and so to build basically
00:28:21
the idea that you want to think about is
00:28:23
to build organic matter you got to build
00:28:25
the below ground habitat so if the
00:28:27
microbes are incorporating active
00:28:29
organic matter into their bodies stable
00:28:32
soil matter pool will also grow so the
00:28:38
idea is that if these microbes are
00:28:41
incorporating active matter and going
00:28:44
through this process of decomposition
00:28:46
then that active matter eventually will
00:28:48
become stable or get better and
00:28:50
when you have more and more stable
00:28:52
organic matter then that'll just keep
00:28:54
pulling up and you'll just keep adding
00:28:55
and adding and adding organic matter
00:28:58
another thing is to have plants in the
00:29:02
soil and so because living roots really
00:29:06
keep microbes happy it's a high quality
00:29:07
food source it kind of boosts their
00:29:10
activity it's just a quick delivery of
00:29:12
nutrients to them so if you have
00:29:15
something planted in the ground the
00:29:17
microbes become even more happy and are
00:29:20
willing to work and build more organic
00:29:22
matter these pictures just kind of tell
00:29:28
the same thing hopefully in a quicker
00:29:31
quicker way so four steps to building
00:29:34
soil organic matter this says in the
00:29:36
south but really anywhere minimize soil
00:29:39
disturbance keep the soil covered with
00:29:41
living roots so you know plants sitting
00:29:44
there on the soil jack up your diversity
00:29:47
so all sorts of different plants with
00:29:49
different atriums are going to make it
00:29:52
easier to have more nutrients available
00:29:55
for your microbes and then focus on soil
00:29:57
resiliency how do you make your soil
00:29:59
stronger and better and healthier and on
00:30:03
the right they're managing soil organic
00:30:05
matter is the key to air and water
00:30:07
quality so if we want to have healthy
00:30:09
air and healthy water and productive
00:30:11
soil we need to have soil health and we
00:30:14
need to manage for that soil health but
00:30:19
if we can build soil organic matter then
00:30:21
we can definitely destroy soil organic
00:30:24
matter so what what kind of things do we
00:30:27
do that would end up destroying soil
00:30:29
organic matter so the biggest thing is
00:30:31
that soil organic matter builds when the
00:30:34
soil is occupied by vegetation and not
00:30:36
disturbed that's kind of what we were
00:30:38
just talking about before so well how
00:30:42
would we destroy it well then obviously
00:30:43
if we don't have education and we
00:30:45
disturb the soil that's where we're
00:30:47
gonna run the problem so some sort of
00:30:49
physical disturbance where we're
00:30:51
disturbing the soil like when the land
00:30:54
is tilled soil structures that holds and
00:30:58
protects that organic matter we talk
00:30:59
about that with the aggregates providing
00:31:02
armors for the
00:31:04
organic matter when that's broken and
00:31:06
disturbed then the organic matter is
00:31:10
that was protected is now exposed to
00:31:13
these composers and so we can leave that
00:31:16
organic matter that way and then also
00:31:17
just the idea that the soil becomes so
00:31:20
aerated that you get this rapid loss of
00:31:22
carbon as carbon dioxide a loss of
00:31:26
carbon dioxide into the atmosphere if we
00:31:29
would we remove residues so the idea
00:31:33
that if the soil isn't occupied by
00:31:35
vegetation we take all the vegetation
00:31:37
off residues are just basically the idea
00:31:39
of what's left over after a harvest so
00:31:41
if we take off everything off of the
00:31:44
surface that's going to make it hard to
00:31:47
build the soil organic matter because we
00:31:49
don't have that source of material that
00:31:52
really helps kind of boost up the
00:31:54
microbial activity so we really need to
00:31:56
be cautious about how much residue we
00:31:58
removed from the field erosion then of
00:32:01
course would then be a problem because
00:32:03
topsoil has the highest concentrations
00:32:05
of soil organic matter in the soil but
00:32:07
then topsoil is also the layer that is
00:32:09
subject to wind and water erosion so if
00:32:12
the topsoil would were to disappear then
00:32:14
we'd also lose the majority of our
00:32:16
organic matter the other the other way
00:32:21
to destroy soil organic matter is if our
00:32:24
carbon to nitrogen reach ratios aren't
00:32:27
where they need to be and this really
00:32:29
influences decomposition speed so a
00:32:33
residue with a carbon to nitrogen ratio
00:32:35
of 25 to 1 is the perfect balance as we
00:32:38
can see in this graphic on the top right
00:32:41
it's the perfect balance but energy and
00:32:44
nutrients for the soil microorganisms if
00:32:47
though you get it higher - higher when
00:32:51
you get like 400 to 1 in terms of more
00:32:54
carbon then then you have nitrogen it's
00:32:59
not gonna provide enough nutrients to
00:33:00
support high microbial activity and
00:33:03
biomass basically the microbes can't get
00:33:05
big and they can't work they're gonna
00:33:07
the everything's gonna kind of slow down
00:33:10
and the microbes there's not going to be
00:33:12
enough enough material available for
00:33:16
them
00:33:17
so then they're gonna just start looking
00:33:19
around and saying I need more nitrogen I
00:33:20
need more nitrogen I gotta go find
00:33:22
nitrogen so they're gonna go take up any
00:33:24
nitrogen that they can find
00:33:26
so those soil solution stuff that maybe
00:33:28
would be going to the plant or going to
00:33:31
the soil now all of a sudden is going to
00:33:33
the microbes because they don't have
00:33:34
enough nitrogen for that for them so for
00:33:37
themselves and they don't have enough
00:33:39
nitrogen to survive and they're like nah
00:33:40
forget that I mean go get some nitrogen
00:33:43
so they'll go find as much nitrogen as
00:33:46
they can find to to survive so we call
00:33:49
that immobilization or where nitrogen is
00:33:52
immobilized because the microbes don't
00:33:55
have enough so they're gonna just
00:33:56
scavenge up all the free nitrogen and
00:33:58
then we're gonna see a lack of nitrogen
00:34:00
going to our plants or being in the soil
00:34:04
where as residues lower than 25 to 1
00:34:07
manure and alfalfa those are good
00:34:10
examples with manure being 20 to 1
00:34:13
carbon to nitrogen 12 to being close to
00:34:16
1 they'll supply plenty of nutrients
00:34:18
kill microbes so decomposers have all
00:34:20
the nutrients they require so they're
00:34:22
gonna remain active and the decompose
00:34:24
there's will the decomposition is going
00:34:28
to occur it quickly so surplus nitrogen
00:34:30
then we'll be mineralized so the idea
00:34:34
that it's it you'll have this surplus
00:34:36
nitrogen and it's going to just kind of
00:34:38
become mineralized it's going to be
00:34:39
available and do any kind of free
00:34:41
nitrogen so if you have too little
00:34:45
nitrogen the microbes are gonna go all
00:34:48
over the place to try and take up
00:34:50
nitrogen and you're going to end up with
00:34:51
problems if you have too much nitrogen
00:34:53
that's also coming be a problem although
00:34:56
much less of a problem because it's just
00:34:59
gonna be the idea that there's free
00:35:00
nitrogen around and it's kind of more
00:35:02
like nitrogen is not getting used up
00:35:04
it's just mineralized and and maybe
00:35:06
being leached or volatilize so how can I
00:35:15
sum this whole thing up soil organic
00:35:17
matter matters a lot it's responsible
00:35:20
for maintaining a healthy productive
00:35:22
soil especially just in the idea of
00:35:25
providing food and a house for microbes
00:35:27
and microbes we know are important to
00:35:30
the function
00:35:31
healthy soil which means soil organic
00:35:33
matter is important to the function of
00:35:35
the function of healthy soil which means
00:35:37
that these the idea of organic matter
00:35:41
and microbes are really key drivers of
00:35:44
the soil ecosystem soil organic matter
00:35:47
also helps protect our soils from
00:35:49
erosion losses through the idea of water
00:35:52
retention and drainage and soil
00:35:54
structure and that nutrient cycling
00:35:58
through the through the plant and the
00:36:02
soil practices that are good for
00:36:04
building and maintaining organic matter
00:36:06
in the soil result in a cascade of
00:36:08
benefits that complement one another and
00:36:11
keep the soil healthy and it's really
00:36:12
just a very good example of an ecosystem
00:36:15
of everything having to work together
00:36:17
and work in balance and being harmony
00:36:19
for you to get the best results and then
00:36:23
soil managed with the organic matter in
00:36:25
mind as a soil that will be strong
00:36:26
healthy and resilient long into the
00:36:30
future and so that's all I've got to say
00:36:35
pretty much about the idea of soil
00:36:37
organic matter I'll just leave you with
00:36:38
what I thought was kind of a very cool
00:36:42
little graphic in that most the time you
00:36:45
see these kind of release
00:36:48
you know circular cycle graphics but the
00:36:51
thing that I thought that was
00:36:52
interesting about this one was the idea
00:36:54
of all those hands being in there and
00:36:56
the idea that you know since we are here
00:37:00
and we are the ones using the soil and
00:37:02
causing some of this loss and are the
00:37:06
ones using these plants and putting
00:37:07
different plants in the ground we really
00:37:09
have to think about how we have our
00:37:11
hands in the soil and how we are doing
00:37:13
this and are we managing the soil the
00:37:16
right way and are we thinking about how
00:37:18
important soil organic matter is and
00:37:21
where organic matter fits in terms of
00:37:24
this whole cycle so hopefully you guys
00:37:28
enjoyed that and I will talk to you next
00:37:31
time
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