Don't Wash That Dirt Away

“Aw, Mom,” a boy groans. He doesn't want a bath. His sister pouts when told to wash her dirty hands. Would everyone be happy if there were no dirt? Not farmers. They couldn't plant their corn. Not earthworms. They couldn't dig their holes.

An earthworm's home, and the dirt around it, can be called a factory. This factory makes a special kind of dirt called topsoil.

Millipedes, spiders, and many other tiny insects live in a worm's home. It's like an insect highway. We might call the walls plain old dirt, but they are really tiny bits of stone piled one on another. The pieces of rock are held together by a kind of cement called humus. It is made of dead and decayed bodies of plants and tiny animals.

Small plants such as fungi and algae supply food for the hungry travelers. Fungi are the kind of plants that grow on moldy bread. Algae grow in damp places. When the roots of plants die, they leave paths for water. Air also comes down the same pathways.

As the water trickles down, it washes the sides of the tiny stones. It washes over the humus and gathers minerals. This is called soil solution. It is full of the nutrients that plants need.

The soil solution, humus, and tiny rocks combine to make topsoil. Without topsoil, there could be no plants. Without plants, there could be no animals on land. Without topsoil, Earth would be an almost lifeless globe revolving in space.

there is cross sectioned picture of topsoil.

Activity

  1. How might the topsoil in a desert be different from the topsoil found in a rainforest? Write a few sentences explaining your answer.
    Answer: Answers will vary but could include that the topsoil in a desert would probably contain little water because deserts do not get much rain. With little water, there would probably not be very many plants or insects. The topsoil in a rainforest would have a lot of plants and insects in it because a rainforest gets a lot of rain.
  2. Imagine you want to plant a garden in soil that is very sandy. What might you add to the soil to help your garden grow? Write a sentence or two to explain your answer.
    Answer: Answers will vary but could include that darker soil that is rich in humus could be mixed into the sandy soil to help the garden grow. Live earthworms could also be added to the soil to help get water and air down to the plant roots.

Activity

  1. How might the topsoil in a desert be different from the topsoil found in a rainforest? Write a few sentences explaining your answer.
    Answer: Answers will vary but could include that the topsoil in a desert would probably contain little water because deserts do not get much rain. With little water, there would probably not be very many plants or insects. The topsoil in a rainforest would have a lot of plants and insects in it because a rainforest gets a lot of rain.
  2. Imagine you want to plant a garden in soil that is very sandy. What might you add to the soil to help your garden grow? Write a sentence or two to explain your answer.
    Answer: Answers will vary but could include that darker soil that is rich in humus could be mixed into the sandy soil to help the garden grow. Live earthworms could also be added to the soil to help get water and air down to the plant roots.