by Melissa Jaramilllo and Julie Snyder
Earthworms! At first glance, they seem wiggly, slimy and maybe a little scary. But they're really very interesting and useful organism.
Have you ever held one in your hand? It stretches forward and then pulls itself in tightly, stretches forward and pulls in. And in no time at all it has moved across your hand! Earthworms use these tiny muscles to dig through soil. While most of us know that earthworms burrow in the soil, we're not so sure how that helps keep soil and plants healthy. Here are two ways:
- Those tunnels help aerate (or allow air to move through the soil and reach plant roots) the soil. The same tunnels also help to drain water from the soil and carve paths for plants roots.
- They eat and break down dead plant material like dried up leaves (humus). They also leave castings (manure) behind. These castings are sources of nutrients for plants. Turning humus into a rich soil helps plants get the right nutrients. Plants need nutrients like people need vitamins!
Watch earthworms at work!
For this activity, you'll need:
- Two clear quart-sized jar
- Organic matter -- brown leaves, twigs or dead plant matter
- Soil -- two different types
- Earthworms (find some in the garden or buy at a bait store)
- Dark construction paper
- Rubber bands
- Cheesecloth or thin netting
In each of your jars, put about two inches of sand in the bottom. Then layer two inches of soil, followed by two inches of the other soil. Finally, spread your humus at the top. Last year's dried leaves work best, crushed into small pieces, but not powdered.
Drop your earthworms into one jar, cover the top with netting or thin cloth and wrap black construction paper around the jar to keep it dark, like underground. Hold the construction paper and cheesecloth in place with rubber bands. Do not add worms to your second jar; just cover it and wraps it with construction paper. This jar is your "control."
Keep the soil moist, but not soggy. Worms absorb the oxygen found in air through their moist skin.
The next few days, remove the black paper for a peek at your earthworm farm. Is there a difference between the control and the farm? Have your hard-working earthworms have tunneled and mixed up the different layers of soil? Has anything happened to your organic material? Are there any changes in the control?
Return your worms to the garden or extend your experiment to a worm bin!
- Use different species of worms to see how they differ in their affects
- Use different types of leaf litter (keeping the worms species the same) to see which the worms eat fastest (ie. maple vs. oak, or maple vs. pine)
- Start a worm bin for your family's vegetable peelings and other organic material
Some neat worm facts:
- Earthworms are members of the phylum Annelida, or ringed animals. They are fairly simple life-forms, put together from a number of disklike segments stuck together like a long flexible roll of pennies.
- If it is too dry or too cold earthworms know what to do! They burrow deeper into the soil. They may also coil into a slime-coated ball and go into a sleep-like state called estivation. It's similar to hibernating!
- Scientists believe the worms probably were brought here from Europe by settlers. Most likely "they came with the settlers in ship ballast, seed stock, potted plants and who knows what else," says Dr. Dennis Linden, a soil scientist who works at ARS' Soil and Water Management Research Lab in St. Paul, Minn.
- There are about 50,000 worms in every acre of soil.
- Earthworms don.t have lungs or gills. They breathe through their skin.
- The study of worms is called helminthology. Our experiment could have been called, "A lesson devoted to helminthology!"
Julie Snyder is a mom of six, interested in kids, pregnancy, birth, people and lives in the outlying Seattle area. Melissa Jaramillo is mom to many. She's passionate about building, encouraging, and strengthening families on this adventure known as parenthood!
Copyright © Melissa Jaramillo and Julie Snyder. Permission to republish granted to Pregnancy.org, LLC.