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  • For most of my life, I've given little thought to the soil.

  • To me it was the flat surface that I walked on.

  • I've been thinking a lot more about it these days and what I learned has

  • surprised me.

  • I learned that soil is like the earth's skin

  • that lies between the

  • sky and it's rock core.

  • It's where plants keep tenuous grip with their roots,

  • as they harvest the sun's energy with their leaves.

  • I begin to realize that soil is alive.

  • That a handful of good soil contains more living things than all the human

  • beings that were ever born.

  • It dawned on me that without soil

  • life as we know it would not exist.

  • If soil is alive

  • I wondered if soil could die.

  • I visited with Pam Thomas and spoke to her about this.

  • A recent historical example is the Dust Bowl.

  • In the early part of the 1900's homesteaders plowed

  • millions of acres of prairie lands in order to plant crops, mostly wheat, because

  • wheat was bringing very high prices during the

  • World War one wheat boom.

  • Well because of this intensive cultivation

  • uh... the delicate balance - the ecosystem- was essentially destroyed - you know you

  • had the plants, the animals and the micro-organisms

  • to the point of where the soil no longer was able to function.

  • So as the wet years of the twenties gave away to the

  • drought of the

  • thirties,

  • the soil, which

  • no longer had the natural anchors to keep the soil in place, became very

  • susceptible to wind erosion.

  • In fact in the nineteen thirties

  • dust storms would start the great plains and would move cross-country to places like

  • Boston and DC....

  • Meanwhile in the southern US piedmont,

  • plowing and monoculture crops destroyed soil,

  • causing massive gully erosion.

  • Some of these gullies are still visible today.

  • No wonder FDR said that

  • "the nation that destroys its soil, destroys itself."

  • These were dramatic examples of soil destruction,

  • and I got to thinking how we were doing today.

  • We're still losing soil today. It's not as obvious to us today as it was in the Dust

  • Bowl thirties

  • but it's an ongoing crisis because....

  • the bottom line is, we are feeding more and more people on fewer and

  • fewer acres.

  • We're literally losing ground.

  • The nationalist Aldo Leopold warned us that one of the dangers of

  • living away from the land

  • is that we are inclined to think that our breakfast comes from the grocery store ...or a carton.

  • This got me to wondering how much soil we had to feed

  • our planet.

  • My soil scientist friend Jackie helped me understand this. Imagine for a moment

  • that the earth is this apple... seventy-five percent of the earth is covered by water...

  • Now half of the dry land on our planet is too hot or too cold

  • to produce food for humans.

  • Of this amount, about half is too rocky, steep or too shallow to produce

  • food.

  • It doesn't take a rocket scientist to figure that there's not much left

  • over.

  • And then what we have left is under pressure from things like urban sprawl

  • and erosion.

  • It takes five

  • hundred years to form an inch of soil,

  • something that can be destroyed in a few minutes,

  • and that worries me.

  • Leonardo DaVinci said that we know more about the movement of celestial bodies

  • than about the soil underfoot...

  • I'm guilty as charged

  • but i'm not going to leave it that way.

  • Join me in the rest of the series to find out what soil really is and what it

  • means to us...

  • perhaps if we learned more about soil we'd be better eqiupped to take care of the

  • planet.

  • If life is we know it depends on the soil,

  • it stands to reason that what happens below the soil's surface has a profound

  • influenced on what happens above the surface.

  • My knowledge of soils needed to run deeper.

  • The people that could help me do this were the soil scientists -

  • their work is to look beneath the surface into this life-giving, yet unseen

  • world.

  • Each day in the field is an adventure of discovery for them -

  • they have their own vocabulary and they love the feel of dirt in their hands.

  • this was the soils dream team, and they would be my teachers for the

  • next few weeks.

  • Dennis is a veteran who has mapped over a million acres of soils in his lifetime.

  • Lance and Emory are also seasoned soil explorers who have discovered a new soil

  • series that bears their respective names.

  • This was going to be fun.

  • the first thing they showed me was how the soil was formed.

  • This happens when weather and living plants and animals breakdown loose rock,

  • called parent material.

  • Parent material is typically weathered bedrock that over time becomes the main

  • mineral component of the soil.

  • It looks like rock when you dig it out, but as you can see

  • it's very fragile

  • massive structure, breaks easily.

  • Dennis took me to a road cut to show me that overtime, soil is formed in layers called horizons.

  • These horizons tell us about their history

  • and they can also give us clues about their future.

  • This is the A Horizon or the surface layer.

  • Look at all those roots in there.

  • That's wonderful.

  • Dark colors caused by the organic matter in there.

  • In here we have what's called the E Horizon, capital E.

  • Fairly light in color,

  • more sandy in texture

  • and down below it,

  • is our B Horizon

  • that contains much more clay and you can see

  • it's much more red down here, too.

  • Each soil horizon has unique properties

  • like depth, color or clay content.

  • When these horizons are layered on top of each other over time,

  • they form soil

  • profiles which can be identified by name.

  • they are often named for the place they were first identified, like Norfolk

  • or Durham.

  • When it comes to looking below the soil's surface, nothing is as effective as a

  • good old-fashioned soil auger.

  • You'll never find these guys in the field without one-

  • I guarantee it.

  • Now I began to see how soil profiles can tell their story,

  • layer by layer.

  • this is a soil profile

  • put into a long tray so we can look at it a little

  • easier that pulling it out with the auger.

  • In this hand here

  • you'll see this is the A Horizon

  • and you'll see it is much darker cause it contains

  • organic matter in here.

  • This is the A Horizon or the surface layer. This is eight or ten inches below the surface

  • and see how red this is?

  • All soils contain iron and we

  • know if we put a piece of iron

  • outside for two weeks it turns rusty.

  • This is rusty soil.

  • Rusty soil, how about that?

  • So each color has a different meaning-

  • bright reds and yellows mean that a soil is well-drained

  • there's more oxygen

  • in the soil to oxidize or rust the iron in the soils.

  • Grey colors on the other hand, mean the soil is waterlogged for most of the year

  • because there is less oxygen to get at the iron.

  • A dark brown color means more organic matter

  • which is mostly in the A Horizon or topsoil.

  • we can use the Munsell Color book to classify the exact color of the soil.

  • We take the

  • soil ped

  • and put it behind the book

  • and find the colorship that it most resembles.

  • I'm going to say that it's that color there

  • 2.5 YR 4 8

  • 2.5 YR 4 8 by the way

  • is a more precise way of saying "red".

  • Dennis also pointed out to me that soil depth is another way

  • to identify soils.

  • This is the "Cecil series" because the clay content

  • extends below a thirty inch depth.

  • If this clay content decreased above a a thirty inch depth

  • it's called the "Pacolet series".

  • They're kissing cousins.

  • Whoa! kissing cousins?

  • It turns out that if two soils have similar color and clay content,

  • but different depths,

  • they'd be named differently.

  • At this point I knew enough to see how you could identify a specific soil series.

  • I was now ready for Lance and Emory to show me their newly discovered soil -

  • it's named the Brewback series.

  • Right there, about 22 inches

  • we just starting to barely nip on the CR material.

  • You can hear the grind and feel it in the auger.

  • Right here we have the A Horizon.

  • It's about six inches thick and it's a fine, sandy loam.

  • Then we get into the B Horizon, which is a heavy clay.

  • And here, about

  • twelve or fifteen inches, we have the uh...

  • the grey colors

  • coming in, and for a Brewback soil we have to have the grey colors within

  • the top ten inches of the B Horzion.

  • As we move on down the profile about twenty inches, we get the sandy, clay loam,

  • which is the B-C horizon, which is a transition between the B Horizon and the parent material.

  • By this time, I had seen a few soil series,

  • each with its on color, depth, and clay content -

  • each with its own personality if you will. It turns out that soil scientists have

  • identified and mapped over nineteen thousand different soil series in the

  • country.

  • That sounds like a huge effort -

  • I had to find out who was doing the work

  • and why it is so important.

  • I found out that the massive effort of identifying and mapping soils

  • is known as the soil survey.

  • The body of information resulting from this ongoing effort, also known as

  • the soil survey,

  • is available in hard copy and online at the web soil survey.

  • It's an inventory of soil maps, soil properties, suitabilities and

  • limitations.

  • I was reminded that what happens beneath the surface of the soil ultimately

  • affects everything above its surface.

  • Everything.

  • That's what makes the soil surveys

  • so important to any land management decision, from farming to disaster

  • recovery planning.

  • I drove out to Lee County to find out

  • who the people were behind all this work,

  • and how soils were mapped.

  • Charlie is a soil scientist who is responsible for the upkeep of about

  • eleven million acres of soil survey.

  • Most of this...all of

  • South Carolina has been mapped,

  • so what we're doing is updating all

  • the older soil surveys.

  • He offered to take us through the process of making a soils map in the

  • field,

  • and I asked him to sketch out the day for us.

  • One of the things we do,

  • when we go through the process of making the soil map

  • is to stand and just look at the area

  • and take in the whole landscape itself. and you can see out in this part of the world,

  • that some areas of it are concave, some of it are more convex.

  • So essentially what we do

  • is to stand out here and note where these areas are,

  • dig the holes,

  • identify the soils,

  • and label them on the map using alpha-numeric symbols.

  • The finished product looks like this.

  • This is the same area that we're standing in, and

  • we can see that these soil lines delineate the different tones on the map.

  • The first hole we dug was on a slight rise...

  • we then moved over to a slightly lower area only three hundred feet away and dug another hole.

  • Charlie showed me the

  • difference between the two soils that was so close to one

  • another, and how

  • land form influenced them.

  • This soil in the front,

  • is the "Rains Series".

  • This soil in the back is the "Nolfork Series" that we looked at earlier.

  • One of the first things we notice is that the surface of the "Rains" is darker

  • and that is reflected by the tones on the map.

  • The other obvious thing is that the subsoil is much grayer.

  • Where the "Norfolk" series is dominately brown, the "Rains" is dominantly gray.

  • The grayer