Download All About Worms by Rosemarie Pagano Soil Composition (The dirt

All About Worms
by Rosemarie Pagano
Unit 3: Soil Composition
“The earthworm plows the whole world with his tunnels, drains and aerates the earth . . .
If you ever buy any land, be sure it has plenty of earthworms toiling and moiling all day
so that you can sit down and relax.” Will Cuppy, 1949
Dear Worm Amigo,
You’ve complete two weeks of Wormology! Great job. Let’s recap what we’ve learned so far.
Lumbricus terrestris is a fabulous soil aerator, making it not only a good worm but a great worm.
We studied the “wormology” and uncovered fascinating facts about how he/she moves and
grooves, feeds, and feels.
I also uncovered a common myth, which I believed for a long time, and that is when it rains
earthworms come out of their burrows to keep from drowning. I’d put on my raincoat and boots
and run around the yard scooping them up and bringing them to safety! That wasn’t necessary.
Here’s what I learned:
Do you remember that earthworms need moisture in the soil to breathe? Even the mucus layer,
produced by the clitellum, helps them to stay moist. These two factors, moisture in the soil and
the mucus, allows oxygen to dissolve and pass into the worm through their main organ, the skin.
One reason they come out of their burrows, when it rains, is to find a mate. Their glandular
secretions, from the clitellum, are what attracts them to each other. Another reason is the CO₂
levels build up in the burrows, due to respiration, which forms a weak acid solution. They don’t
like an acidic environment, again, because of their sensitive skin.
Well, I am glad I got the facts. A junior scientist never stops learning!
See you soon,
RBW₂
Soil Composition
(The dirt on dirt!)
We’re going to get down and dirty to see where worms live and the “waste” they produce. I hope
you get outside, with your magnifier, to see worms in their natural habitat.
The soil is a treasure trove of nutrients made of decaying organic matter. As animals and plants
die and decompose, they are broken up into smaller particles called humus. This dark organic
part of the soil holds water, feeds plants, and keeps the soil from getting too hard for plants to
grow in. Another part of soil is made up of inorganic matter like rock particles. These particles
used to be large rocks or stone and, over time, erosion by wind and water produced soil particles.
Take a look at a sand particle. Doesn’t it look like a tiny rock?
The earthworm eats and breaks down large pieces of decaying matter. They eat bits of rock (the
gizzard uses this to grind the food) and humus, digest what they can, and deposit the rest as
waste. This waste is called castings which is just a fancy name for worm poop!
Grab a handful of soil and smell it. Take a good look at it and crumble it between your fingers.
Different places have different types of soil. It might look sandy, muddy, or like clay. The local
weather, the types of animals and plants in the area, and the kind of rocks in the soil all
determine what it looks like. Soil that looks red means there is iron in the rocks. Here in Illinois,
rotted leaves, roots, stems, and dead insects make up our black soil that is great for growing
because it is rich in humus.
That’s not all. The soil gets help from living organisms. We can’t ignore the important job of
fungi, mold, bacteria, and last but never least, earthworms. The earthworm works like a tiny tiller
burrowing through the dirt, allowing oxygen and water to get down deep. This helps plants to
absorb the water and oxygen. Earthworms bring soil from deeper levels to the top and top soil
down low again. Plant roots get down into the soil easier if they follow a burrow made by an
earthworm. Lumbricus terrestris paves the way! Earthworms come out of their burrow at night
looking for food. They will pull plant matter, like grass clippings, down into the burrow, eat it,
and deposit the waste back on the surface of the soil. The waste, or castings, is turned into
nutrients for the lawn. Wow! These tremendous recyclers work nonstop in their silent “dirty”
world.
The Worm Composting Ecosystem
Worm Amigos!
Listen up. This is my favorite subject. According to Dictionary.com, vermiculture is the raising
and production of earthworms and their by-products. The best worms for composting are in the
second group of terrestrial earthworms, the Shallow Soil Dwellers. I like to call them “Rock Star
Decomposers.” This is Eisenia fetida commonly known as the Red Wiggler, Manure worm,
Tiger worm, Garlic worm (remember stinky worm slime?), and Brandling worm.
Their by-product is vermicompost or worm poop, but I think it is fancier to call it “black gold.”
This is what I sell at the flower show. The gardeners like to sprinkle it around their plants to give
them a power-packed boost of nutrition. Buying a bag of worm poop doesn’t have a nice ring to
it, but “black gold” sounds much more valuable, don’t you think?
Red Wigglers are voracious eaters and process a large amount of organic waste daily into
vermicompost. They reproduce rapidly. They are hardy and can handle a variety of conditions.
You won’t find these worms in the garden or lawn because they like places that are rotting—like
manure and decaying plants and animals. That’s why they can thrive in a controlled
vermicompost system like a worm bin.
Let’s talk about worm bins. Organic (food) waste goes in and vermicompost can be harvested
and sprinkled on lucky plants and flowers. Sounds easy? Well, there’s a lot of action going on in
this complex ecosystem. Let’s look at the other two key players and what they bring to the worm
bin.
1. Microbes or microorganisms (bacteria, fungi, protozoan, actinomycetes). These
organisms, in a worm bin, really do most of the work. You might say, “out of sight, out
of mind,” but these invisible powerhouses of activity are really the primary decomposers.
A. Bacteria. They are everywhere! These tiny single-celled organisms, typically rod or
sphere shaped, hang out in every habitat imaginable. Bacteria have numerous jobs in
the biosphere, but in the worm composting arena they are primary decomposers.
When they join forces with fungi, watch out! They break down organic matter and if
we didn’t have these tiny team players we’d be up to our necks in waste. Yikes!
Aerobic (needs air) bacteria in our worm bins is what we aim for because that will
result in a properly functioning system. Stinky smells usually come from anaerobic
(no air) bacterial activity which happens and unfortunately can cause parents to
threaten to end the fun. I’ll tell you about my experience with “stinky” later on.
Earthy smelling, glorious, rich, vermicompost is the result of bacterial activity that
has gone right. It’s taken me much trial and error, and some mishaps, to get to this
stage.
B. Actinomycetes. We can’t forget this unique soil bacteria that shares some features
with the fungi. Actinomycetes have a filamentous morphology which means they can
spread out wherever they live. They can be either aerobic or anaerobic. The typical
rod and sphere bacteria aren’t the only divas in the decomposing show. These
spreaders have super rock star capabilities as brilliant decomposers.
C. Fungi. There are many fungi that are microscopic but I, as a Worm Whisperer, am
familiar and always on the lookout for the visible “fun-guys” like the fuzzy mold on
old bread. Fungi can be more visible because they form complex structures. The
fuzzy stuff is the “mycelium that is made up of a mass of hyphae that form the
vegetative part of a fungus” (Dictionary.com). Mushrooms are fungi with fruiting
bodies. Fungi breaks down material and provides a source of food for the worms.
They like an acidic environment so if I see a lot of “fuzzy” it means an overgrowth of
fungi due to overfeeding. Remember—worms don’t like acidic environments. So, this
is not a healthy worm bin.
D. Protozoans. We see these single-celled organisms in pond water. Paramecia and
amoeba are part of this group and are important in compost ecosystems and in garden
soil. I call them “bacteria slayers” because they act as predators and keep bacteria
from taking over. While they are showing bacteria who’s boss, they are returning
valuable nutrients to the environment. The worms thank the paramecia and amoeba
for their important work by eating them!
2. Other Invertebrates. These “dirty denizens” are decomposers but they can get out of
hand and cause trouble. Here’s a list of the most common “nasties.”
A. Arthropods. This group has body segments like a worm but a semitransparent horny
substance called chitin forms an outer covering (exoskeleton). Unlike worms, they
have jointed limbs and their chitinous shell can be shed and replaced by new growth.
This large group includes insects, spiders, and other arachnids like scorpions, mites,
ticks, and daddy long legs. They have no antennae and eight legs.
B. Insects. This group includes fruit flies, fungus gnats, soldier flies, ants, and various
types of beetles like the rove beetle.
C. Centipedes and millipedes.
D. Sowbugs.
E. Springtails.
My friend Cathy at www.cathyscomposters.com has great video shots of worm bin action. Those
crazy springtails clean out a worm cocoon. Not to be missed!
http://www.youtube.com/watch?v=Yj-_8LGLTcM
http://www.youtube.com/watch?v=weu2NYrvIro
SchoolhouseTeachers.com note: Parents should closely monitor children’s use of YouTube and Wikipedia
if you navigate away from the videos and articles cited in these lessons. We also recommend viewing the
videos on a full screen setting in order to minimize your students' exposure to potentially offensive ads.
Guess what, Worm Amigos? In our Week 4 lesson, I am going to tell you all about how you can
have your own recyclers work for you and produce “black gold.”
Bye for now!
RBW₂