What Is Soil Made Of?

Lesson Plan - Get It!

Audio:

Soil is used to grow most of the plants on earth.

This means all of the fruits and vegetables you eat come from plants that grow in soil. The wood that was used to make your house is made from trees that grow in soil. Without soil, we couldn't live!

• Do you ever wonder what is in the soil that grows our food?

To start, print the Graphic Organizer - KWL chart found in the Downloadable Resources section of the right-hand sidebar.

In the K column of the KWL chart, make a list of the things you already Know about soil. This can be what it is used for or where to find it or who needs it.

After you have created your list of what you know, move to the W column and write down what you Want to know about soil. As you complete the W column, think about:

• What you want to know and explore about soil.
• Making a list of at least three things you want to know about soil.

It is time to take a closer look!

There are both living and non-living things in soil. Without all these things working together, the soil that grows our food would not have enough nutrients in it to grow anything!

• Did you know that living and non-living things can work together?

Living Things in Soil

• Did you know worms are a very important part of our soil?

Worms act like tiny little helpers in the soil. They eat and break down all kinds of materials, like leaves and grass, into food for plants. Worms in your soil are the best thing you can have!

Ants also do an important job in the soil because they make tunnels that allow water to flow to the roots of plants. These tunnels also help move plant seeds from one place to another.

• Who knew that such tiny creatures could make such a big difference?

Another important living part of soil is bacteria.

A single bacterium is so tiny, you need a microscope to see it, but thousands and thousands of these tiny creatures also live in the soil. Bacteria are important because they change the soil's structure to make it possible for plants to grow.

Non-living Things in Soil

There are many non-living — meaning they were never alive — things in soil.

For example, water and air are two non-living things in soil that are very important. To see water in the soil, you may just see a difference in the color. Wet soil is often darker in color than dry soil.

Air is a non-living thing you cannot see, but it fills the tiny spaces in soil.

There are many rocks in soil, as well different kinds of sand. These are naturally occurring, meaning no person put them there; they are part of soil's natural composition.

There are other non-living things that end up in soil that are put there by human beings.

For example, some farmers use chemicals like pesticides to keep insects off their crops. These chemicals end up in the soil. Some people also use fertilizer to help their soil with vitamins and minerals.

In the winter, some places get snow and ice, and people put a chemical on the road to keep it from being slippery. This chemical, known as magnesium chloride, ends up in the soil. Some states use rock salt to help with icy roads, and that also makes its way into the soil.

As you can see, there are many different things that can end up in the soil that grows your food! Some things are good, and some things are bad. Keeping as much of the bad out of the soil as possible is important for the quality and nutritional value of the food we eat.

Now that you are a soil expert, see if you can answer the questions about soil in the Got It? section!