SOIL … It’s more than just dirt! Learn all that you ever wanted to know about the stuff beneath your feet.

What is soil? Soil is formed as a result of weathering. It is made from particles of rocks, minerals, dead plants and animals, living organisms, gasses and water. The particles of rocks and minerals have broken away from larger ones through weathering. Most of these pieces are very small.

What’s an organism, and what is it doing in my soil? Organisms are living plant or animal life. They are very important to soil. Some of them are decomposers.

Decomposers These are tiny organisms that break down dead animals and plants into NUTRIENTS! NUTRIENTS are substances needed by living things. The decomposers take dead organisms and turn them into nutrients that plants and animals can use for food. Without decomposers, plants can not grow.

Soils have layers If we dig a hole in the ground, we can see that the soil has layers. We can look at these layers in a cross section. These cross sections are called Soil Profiles.

Soil Profile They show us the different layers of soil. Topsoil Subsoil Bedrock

Bedrock Let’s start from the bottom. Bedrock is the solid rock that lies underneath the soil. It can be within inches of the surface, or many feet below. Because it has no nutrients, and it is tightly packed, there is no organic mater here. (organic mater is things that are or were alive.) Bedrock

Subsoil The stuff in the middle. Subsoil is just below the topsoil. It is made up of tiny particles of rocks and minerals mixed with larger ones. It has very few organisms in it because it is tightly packed, and has few nutrients.It is hard for plants to grow there. Subsoil

Topsoil This is the good stuff! Topsoil is finer than subsoil, and is usually darker in color. That is because it is loaded with nutrients and organic matter. It has an abundance ( a lot) of organisms.

Why is topsoil cool? Without topsoil, plants have a very hard time growing. They just can’t get what they need from subsoil. Topsoil forms over a long period of time. In Utah, it takes about 1,000 years to create 1 inch of topsoil.

What is topsoil made of? 45% : Minerals (clay, silt, sand, gravel, rock) 25% : Water (Sometimes a little more or less) 25% : Air (organisms need this) 5% : Organic Matter (Both living and dead organisms)

We Must Save The Topsoil! If topsoil is cleared of plants to hold it down, it can be swept away by erosion. When this happens, it is very hard to grow plants there again. We must protect topsoil from erosion by making sure that the plants holding it down are healthy. That’s the end. Now, go dig a hole.