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Now we're gonna talk about the last component and that's soil structure.
Soil structure is the arrangement of the sand, silt and clay particles in a soil.
There are actually six types of soil structure that you can have.
The first structure is granular structure.
It's these fine particles, which are actually stuck together
by organic matter, and fungal hyphae and things like that.
Gives you good granular structure.
So the more organic matter that you have,
the better your granular structure is going to be.
The next type of structure that you have is something called platy structure.
Looks just like a series of plates.
The technical term for it is actually lenticular structure.
And what's interesting about having platy structure in your soil is that,
think about it for a minute.
You have a water droplet, water coming down hitting the top of this plate.
It has to move in a horizontal direction, Right?
Falls, hits the next plate, has to move in another horizontal direction.
So when you have lots of platy structure in your soil,
chances are you're gonna have a poorly drained soil situation.
And actually, you can get platy structure to form in your soil,
by the type of tillage practice that you do.
You do a lot of mobile plowing or conventional tillage,
you're gonna get the formation of platy structure.
So in the B horizon we actually have two types of structure.
We have what is called subangular blocky structure,and angular blocky structure.
And with subangular blocky structure,
the edges of the blocks are actually rounded off.
Versus angular blocky structure where you have these sharp angles,
which occur in the blocky structures.
Also in the B horizon, you could have what is called prismatic structure.
And prismatic structure is long in the vertical direction,
sort of short in the horizontal, it's got sharp edges.
You can also have prisms that are smaller.
You can have small prisms, you can have large prisms.
The size of the structural unit is pretty irrelevant, because
you can have all sorts of different sizes for these different types of structures.
The other type of structure that we have in the B horizon,
is something called columnar structure.
And columnar structure is not so common here in Indiana, but we do see it.
It's where you have a lot of salt in your soil.
And what happens is that, that salt causes the tops of the prisms to disperse
and sort of round off and you end up with what's called columnar structure.
What's the situation down in the C horizon, where the parent material is?
Actually we do have what is called structuralist units in the C horizon.
And usually that consists of sand or
it consists of a massive type of structure,
everything just kind of glued together.
So let's conclude by looking at the soil structures in a soil monolith or
soil profile.
Top of the soil profile, the A horizon, that's where you find granular structure.
In the E horizon, that's principally where you're gonna find platy structure.
Down here below the E horizon going into the B horizon,
that's where you have subangular blocky.
In the B horizon itself, this is prismatic structure.
And down below, this is where we find angular blocky structure.
And then, as I mentioned in my discussion, in the C horizon, there's no structure.
It's a structureless condition, but we have a massive condition in the C horizon.
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