Soil Erosion: What it Is and How it Affects Our World

Soil erosion happens when soil is carried by the wind or water from one place to another. Erosion is a natural process, but human activities can sometimes make it worse. When people remove trees or plants from an area, the plants' roots aren't there to hold the soil in place anymore, so it's more likely to erode away. And whenever people do things to change the shape of the landscape, like building roads and bridges, it can change how the wind and water move as well as reduce the amount of vegetation, both factors that can increase soil erosion.

Why Is Soil Erosion a Problem?

You only have to look back to the 1930s to see the worst example of how soil erosion can hurt us. In that decade, soil erosion and droughts led to crop failures and severe dust storms. Farmers tore up acres of grassland to plant crops, taking away the deep-rooted plants that had held the topsoil in place. Then, when a drought came and the crops died, the soil blew away. Without healthy topsoil, new plants can't grow. This problem remains today; when erosion leads to the loss of topsoil, crop yields fall and our food supply suffers.

Water can also erode the soil, and this water eventually ends up in rivers and streams, carrying the soil with it. This sediment then precipitates out of the water, making the water shallower and clogging the waterway over time. This causes harm to the ecosystem, killing the fish that live there, and it can also lead to flooding.

What Can We Do to Prevent Soil Erosion?

One of the most important things that people can do to prevent soil erosion is to plant grasses, shrubs, and trees that can help to hold the soil in place. Farmers should also use cover crops and crop rotation to keep their soil healthy. People can also pay attention to the runoff on their property when it rains and take action to redirect it and slow it down. The best way to do this is by constructing a rain garden that can encourage the water to seep into the soil instead of washing the soil away.

Experiments to Help Kids Understand Soil Erosion

Simulating Wind Erosion

Materials:

• A small bowl
• Sand
• Fan

Instructions:

• Fill the bowl with sand and place it in front of the fan.
• Turn on the fan and watch what happens to the sand.

The sand will be blown away by the fan because there's nothing to hold it in place.

Understanding Water Erosion

Materials:

• Two identical baking trays
• Soil
• Water
• Small plants or grass
• Measuring cup

Instructions:

• Place the baking trays side by side on a flat surface. Put some soil in both of them. Add the plants or grass to one of the trays.
• Hold up one end of the tray with soil on it so it's tilted, then pour a cup of water onto the tray at the top end. Watch what happens to the soil.
• Repeat this process using the tray with soil and plants on it and watch what happens.

When the water is poured over bare soil, it gets washed away. But when you pour water over soil that has plants holding it in place, a lot less of the soil will erode.