Soil, dirt, earth, muck – there are lots of words for soil. One we don’t often hear associated with soil is life.

Soil keeps us alive

Where would be without soil? According to one soil scientist, we’d be “hungry, thirsty, naked, homeless and breathless”. Our food comes from soil. Even fish and other things that live in lakes or the sea depend on soil. Nutrients wash off the land and into the water, helping things to grow.

Soil cleans and stores the water we drink. This might sound odd – wouldn’t soil make water dirty instead? When it rains onto streets, farms or other areas, water droplets can pick up pollutants from oil or cow poo. If this water goes straight into a stream or river, it carries the pollutants with it. If the water seeps into the soil first, the soil can hold on to these pollutants. Soil microbes recycle some of these pollutants – so soil can clean the water. We pump water from under the ground, clean it a bit more and then drink it or bottle it to sell.

Nature of Science

Cultural, economic and political factors influence how we use soil resources. Scientists provide information about soil and ecosystem benefits, but policy makers are responsible for land-use decisions such as road building or making land available for new housing.

Soil keeps us warm and dry

Much of our clothing comes from the soil. Cotton grows in the soil. Silk and wool come from animals (silkworms and sheep) that eat plants grown in soil. Buildings are made of wood, brick and concrete. Trees grow in soil. Bricks are made of clay from soil. Concrete uses sand and other minerals from the soil.

Soil helps us breathe

Even the air we breathe has a soil connection. Plants that make our oxygen grow in soil. Plants take water from the soil and combine it with CO2 and light to make their own food – and give off oxygen.

Soil means life for other things

Soil is a habitat for a wide variety of life. One quarter of the Earth’s biodiversity (living things) live in soil. This includes things we can see like insects, earthworms and rabbits. It also includes things too small for us to see like bacteriafungi and other microorganisms – billions of microorganisms! There are more tiny living things in one teaspoon of healthy soil than there are people living on Earth!

Soil recycles our wastes

Soil organisms break down wastes and recycle the nutrients. Think about a compost bin and how food scraps go in. Later, dark nutritious compost comes out. We add the compost to the soil to reuse the nutrients and keep the soil healthy. Imagine if our food scraps, dead leaves and cow poo stayed around forever!

Protect soil and protect life

We need to look after soil. Like water, it is a special resource. If we pollute it or lose it, we cannot buy or make more. Soil is lost when wind or water move it away (erosion). We can no longer use soil once we cover it with roads or buildings. Some types of farming can make soil unhealthy by removing too many nutrients or ruining the soil structure.

Healthy soil means healthy life.

Useful links

Watch Dr Dirt (Clay Robinson) as he compares the usable soil on Earth to an apple in this YouTube clip.

Visit the Soil Science Society of America website for short videos of the ways soils support humans and the environment.

    Published 30 June 2015