EARTH: Soil science and composting

Teacher Background

Soil Science and Compost

We might think soil is just dirt that we have to clean off our shoes before going inside. But it’s much more than that. The soil in a garden is alive and breathing. We could think of it as the earth’s skin. Earth has many layers like a big cake. Dead plants and animals, squirming worms and crawling insects on the top and crumbled rocks and sands at the base – yum!

What is Biodegradable?

We use materials that come from the earth every day, for everything we do. Some of these materials such as metals and plastics have been extracted from deep under the soil. They are non-biodegradable, which means they don’t decompose, although many of them can be recycled.

The materials we are going to study more closely in this module are biodegradable. If something was living or originally came from organisms living on or above the soil then it is biodegradable and it does decompose. Another way of saying it is that biodegradable material can be digested by the earth; examples include, food scraps, grass clippings, paper and wood.

Dirt for dinner

Because all the food we eat, including animal products and processed food comes originally from the soil, it makes sense that it can also be returned to the soil. Sadly most of it goes to landfill where it is treated with chemicals and compressed and all the goodness it contains that could have been fed back to earth gets wasted.

Why compost?

There are billions of people on earth and all of them have to eat. That means a lot of food has to be grown in the soil to feed these people. The soil gets tired and worn
out and loses its nutrients, the parts of the soil that help plants grow. Compost returns those nutrients to the soil and helps feed the living organisms that keep the soil healthy and alive. We need healthy soil to grow healthy plants to feed healthy people and animals. Composting is nature’s way of recycling.

Composting also means less resource-use

Reducing the amount of waste that goes into landfill and recycling our food scraps and garden waste into compost uses fewer natural resources, which means less green house gases and less carbon in the air.

So composting also equals carbon busting!