Slo-Mo Soil

 Originally Written May 15, 2020, during a time of ample water.  Rewritten December 31, 2022, for our drought situation. 

Slo-Mo Soil

 

One of the world’s greatest resources moves at its own pace.

When I worked in Wisner, I would drive a half hour one way down the same highway.  During that time, Nebraska raised the speed limit on many of the highways, theoretically lowering the amount of time needed to spend on the road on your way to your destination, but also increasing the chances of something not-to-pleasant happening.  It seems that as time passes, so does everyone’s insistence upon going faster.  As the character Brooks found in the movie The Shawshank Redemption when he was released from prison, the world has progressively got itself into a hurry. 

We also don’t want to wait.  Fast food, instant drinks, guaranteed delivery times, drive-up services, overnight orders, no appointments needed.  We call the postal service “snail mail” because it isn’t electronic, and who writes a letter by hand anymore?  Speed and online dating have been available for years.  Technology does everything now—there’s even an app available for crop scouting.  Too bad it can’t actually walk out there and tell you what’s wrong with your crop. 

Some of the best things aren’t created overnight, though.  There’s nothing like a well thought out, hand-written card sent by mail, addressed to only you, your name written in ink on the envelope.  And although you might meet someone online or via a quick date, can you really get to know them in one date?  It takes time to know someone.  A good wine must age.  So must a good personality. 

 

Soil knows this, too.  It takes a LOT of time to create soil in the first place.  Soil comes from a “parent material”, which is ancient windblown, rain-washed, weather-worn, and time-stamped minerals and materials.  We’re talking eons here.  It takes so long, we consider soil one of our limited resources: because we can’t recreate it in our lifetime. Or several lifetimes.

 

Organic matter content in soil is related to many positive qualities—including aggregation, water infiltration, water holding capacity, soil structure, biological processes, long term nutrient content and capacity, and yield response.  Organic matter is a mix of decomposing manure and plant material, earthworm casts, microbes, invertebrates, and humus.  It takes time to build.  Years, in fact.  You can’t just dump some manure on a field, wait a year, and expect organic matter to jump up significantly.  Soil takes time.  It’s not in a hurry.  You can’t honk a horn at it, flip it off, pass it in the passing lane, or tail it bumper-to-bumper.  It will still take its own time. 

That manure you applied and that old plant matter and those dead critters (microbes, invertebrates, insects, arthropods) in the soil will eventually break down and change into that lovely organic matter to help you out.  It takes chemical and physical reactions that we can’t rush—and we can’t duplicate, either.  We have to feed the system, and create the right circumstances to allow the processes to happen.  But it will happen. 

 

There is a difference between surface and ground water.  Since groundwater is held in the ground, and soil is the ground, recharging or a change in groundwater takes a long time to show up as well.  Recharging the groundwater from the drought of 2012 was just regaining strength in 2020; groundwater levels were rising until our current drought situation, which depleted it considerably.  And the crazy weather we had in 2019?  That was mostly surface water changing through flooding.  In years we have extra surface water: give it time, and extra water hanging about in the surface trickles down into the groundwater, too, and we’ll have more of it in stores—if it doesn’t all run away first.  But it will be accounted for.  Soil just takes time. 

Soil isn’t one big block of solid mass—there are very small “holes” in it, too, and that’s where the air and water are held.  Gradually, the water on the surface travels down to the storage area—the groundwater.  Little by little, if it isn’t used right away for another part of the water cycle, water drops from one “hole” to the next via gravity and osmosis until it is collected into the aquifer.  Then it can be stored until needed later.  That’s a good thing, right?  It just takes time.  Which soil knows it has.  There’s always time for soil.  We as humans just don’t think we have any. 

 

Perhaps we need to take a page out of soil’s instruction book and learn to wait a bit.  What’s another couple of minutes, of hours, of weeks, of years? 

After all, the best things come to those who wait.  Or so I’ve been told. 

 

Thanks for reading,

Julie S. Paschold

May 15, 2020

Rewritten December 31, 2022

Soil Organisms

I spent a full busy day digging in my soil after a long awaited rain, and I thought it was good to revisit what was in the brown stuff that was all over my hands, and supporting my new bushes and fall bulbs as they await the upcoming winter.

What critters are in soil, and what do they do?

Soil may seem like just something to hold up houses or a place for our plants to grow, but there’s a whole world of living critters down there working hard in their individual niches—each critter has an important job that contributes to the health of the soil.  But what are these critters, and what do they do?

1. Animals

a. Burrowing Animals:     These are larger animals, like rodents, moles, badgers, rabbits, armadillos, and such.  They dig into the soil, so can aerate the soil.  But because of their large size, and because some of them also destroy vegetation, they can be more detrimental than helpful at times.    

b. Earthworms: These worms feed on plant residues, and their secretions create aggregates that aerate the soil and increase water filtration and root penetration.  

c. Arthropods & Gastropods: Arthropods are mites, millipedes, centepedes, and insects, including larvae.  Gastropods are snails and slugs.  These critters feed on plant residue and decaying vegetation, breaking it down.  They can also burrow into the soil, aerating it.  Some of these critters can be pests, feeding on living plants.  

d. Nematodes: Nematodes are tiny worms that come in several species, and eat a variety of diets.  Some nematodes eat decaying vegetation, helping to create organic matter.  Some prey on bacteria, fungi, and algae, controlling populations.  And some nematodes are parasites to plant roots.  

2. Plants

a. Plant Root Systems: Every plant has a root system that grows into soil, doing more than anchoring the plant from being blown over or washed away.  Root systems have root hairs and mucous that create ecosystems for microorganisms.  Roots also utilize and circulate water and nutrients in the soil.   

b. Algae: Algae are microorganisms that carry on photosynthesis.  These guys are in the soil in moist areas, and produce organic material.  

3. Fungi

a. Fungi: Fungi are organisms that do not create their own food, but live on dead or living plant and animal tissue.  These include mushrooms, molds, yeasts, and rusts.  They are integral in decomposing organic matter, and the soil contains an abundance of the critters growing within it.  Some fungi can be predators on living cells, creating diseases.     

b. Mycorrhizae: Mycorrhizae is an association between fungi and plant roots.  This is a symbiotic relationship that is integral in assisting with nutrient utilization.  

4. Protista

a. Protista are one celled organisms such as protozoa and slime molds.  They feed on bacteria, keeping the populations in check.  

5. Monera

a. Bacteria: Bacteria are single celled organisms that are the most abundant critters in the soil.  They have many functions, including creating organic matter by breaking down dead tissue, nutrient cycling, and fixing nutrients.  These are very important critters that we would not be able to exist without.  Some, however, can cause diseases to plants and animals.  

b. Actimomycetes: Actinomycetes are a series of branched cells that function similar to bacteria, but work together instead of being on their own as single cells.  They also break down dead tissue, recycle nutrients, and create organic matter.  

6. Viruses

a. Viruses technically aren’t living in the full sense of the word because they are not complete cells, and cannot replicate on their own.  This is why they need to invade other cells to use their replication systems.  Most viruses cause diseases and they can help control population sizes, but they do not usually survive long in the soil.  

So the next time you step out on to that blackish brown stuff holding up your plants, think of all the living things under your feet—and say a little thank you for all of their work.  

Thanks for reading.

Julie S. Paschold

Written July 20, 2020

Reference: Soils in Our Environment, Seventh Edition, by Raymond W Miller & Roy L Donahue, 1995.

Beyond the Horizons: Eating Your Soil

 

Beyond the Horizons—Eating Your Soil

Do you really understand what is under your feet… and what it took to get it there?

 

When I was young, I didn’t ponder on the purpose of that dark stuff under the grass.  It was something that got stuck under my fingernails and was fun to dig up and find bugs in.  It was everywhere—even in the house, if you didn’t wipe your feet. 

So when I opened my textbook on my first day of Soil Science 101, I was nervous.  I knew that there was more to soil than a block of dark matter that held roots and water.  I barely knew anything about farming, much less the intricate details of the teeming ecosystem underneath the crops I was learning about. 

But you know what?  The book actually had some familiar words!  Soil really isn’t that different from you or I in some regards, believe it or not. 

In my first blog, we established that soil is NOT dirt, and that dirt is soil where you don’t want it.   

But what is soil?

Soil is the natural medium for the growth of land plants. 

Therefore, not all of earth’s land surface is covered with soil.  If it can’t grow plants, it isn’t soil.  What isn’t soil?  Polar ice, high elevation areas, hardened lava, salt flats, and bare rock mountain slopes.  If an area has anything that would make a plant recoil its little roots and say “Nope, not going there”—that is not soil. 

Sounds simple, right?  Well, enter NASA and explorers asking about mineral substrates on other planets.  Have you read or seen “The Martian”?  Is that soil?  It isn’t on earth….is oxygen required to make something soil?  I’m not going down that path—that’s for another day and another argument. 

Where did soil come from?

Well, where did YOU come from?  Your parents, right?  Soil has a parent, too—the substance from which the soil was made is called its parent material.  Most soils came from minerals and rocks.  Parent materials go through chemical and physical processes called weathering over many, many years to create loosened material.  In this case, weathering doesn’t mean a soil is checking the radar or the forecasted high temperature.  It means a rock is being worn down into something useful to a plant.  So your mom isn’t the only one who is worn down.  And mom?  Next time you’re frazzled, you can say you are being weathered!  Ha! 

Why aren’t all soils the same?

You may have noticed that not all soils look alike.  Some are deep, almost black, crumbly, and grow just about anything.  Others are light tan, grainy, and seem to blow around too much.  Some soils are red, some salty, some deep, some barely there.  How a soil forms depends on these factors:

·         Parent Material: You aren’t the only one who inherited things from your parents!  Properties such as rates of weathering, nutrient composition, and particle size depend on the substances that the soil came from. 

·         Climate: Precipitation and temperature are the main things in a climate that affect how a soil develops. 

·         Biota: This is a fancy word for living things and their waste, including dead parts and poop of plants and animals of all sizes—even the ones you can’t see. 

·         Topography: This is how the earth’s surface is shaped.  A soil will be affected by how level or sloped the land is, elevation, and even what direction the soil is facing on the slope (does it see lots of sunshine, or is it hidden from the light and heat?). 

·         Time: A soil can take 200 to thousands of years to develop. 

What does a plant need from soil?

So if soil is a medium or substance that can grow plants, what is needed in order to call it soil?  Soil provides the following growth factors to plants:

·         Support: No, not positive affirmations, or tight pantyhose.  Plants need help standing up, and soil provides support as the roots grow into the substrate. 

·         Oxygen: It’s often misunderstood that a plant only gives off oxygen.  It is true that oxygen is a product of photosynthesis, but a plant also needs to breathe, and oxygen is required for this.  Roots need oxygen in the soil.  Little tiny spaces between the loosened parent material hold air that contains oxygen. 

·         Water: Part of those tiny spaces between soil particles hold water, too, and the roots absorb the water as they need it. 

·         Proper temperatures: The roots can’t freeze or fry.  Temperature requirements depend on the species. 

·         Nutrients: Plants require 16 nutrients, 13 of which are supplied by the soil, either by sticking to the soil particles themselves or being dissolved in the water in the pores. 

A soil has layers?

Nope.  And yes.  But read on. 

First, you have the weathering, or creation of small particles.  Then, you have soil development.  These two put together are called soil formation.  It doesn’t all happen at once.  If you dig a deep hole, from the top all the way down to the parent material at the bottom, you would see what looks like layers of soil.  But they aren’t layers. 

Layers are for cakes.

Don’t eat it.  It’s not a cake. 

These areas of variation are called horizons.  The horizon with the least amount of formation will be at the bottom, and the most developed horizon that will grow the best plants will be at the top. 

What kind of horizons are present depends on where you are.  Most soils in my area, the midwestern United States, have an A horizon (the topsoil, where you would find the roots and the most critters crawling around and where a farmer would till and plant crops), a B horizon (a little less developed than the A horizon), and a C horizon (resembles the parent material, but has started to break down).  There are many versions, amendments, subgroups, and additions to this basic idea. 

I can friend a soil on Facebook?

Ha.  Caught you there.  You know when you see someone that is particularly good looking from the side, and think, “nice profile”?  Well, a soil has a profile, too.  Does that mean it can fill out information on Instagram and post silly photos and quips? 

          “The earthworms are tickling me particularly vigorously this morning”

          “This rain is really bringing me to field capacity”

I heard you groan. 

We were just talking about the soil’s profile earlier and you didn’t even know it.  Remember that hole you dug from the top of the soil all the way down to the parent material so you could look at the horizons?  The collection of horizons is the soil’s profile.  A soil profile is a vertical section of the soil through all its horizons and extending into the parent material. 

 

Now that you’ve become a little more familiar with soil, I hope it makes you feel more grounded.  (You’re supposed to laugh here). 

And I hope since you learned that soil has a parent that it has worn down just like you, you’ll feel a little closer to it.  So the next time you see its profile exposed, you can tell it, “Gee, I like you’re A horizon”.  (Ahem….laugh again, please). 

 

Thanks for reading!

 

November 8, 2019

Julie S. Paschold

Reference: Soils in Our Environment by Raymond W. Miller & Roy L. Donahue. 1995. Prentice-Hall, Inc. Englewood Cliffs, NJ