Controlling Soil Erosion

Introduction:

Erosion is the loss of soil from land.  Wind and water are constantly eroding soil.  Soil erosion is a major problem in poor countries along with rich countries such as the United States.  Erosion occurs when soil is transported from one location by wind and water and moved to a new location, such as lakes and rivers.  Soil erosion is a natural process that usually occurs slowly enough that new soil can be made to replace it.  Accelerated erosion is caused by human impact on land use such as over grazing and poor farming practices.  Erosion decreases soil fertility and this causes a decrease in crop production.  It takes 20 to 1200 years to form one inch of topsoil.  The process of erosion can be sped up depending on how fast the water is flowing over the land, the amount of vegetation on a slope also effects the amount of erosion.  Dense vegetation will decrease the amount of erosion by helping to slow the force of the water running down the slope.

 

National Standards Addressed:

The standard of Motions and forces in the category of Physical Science is addressed in this lab.  This lab shows how the motion and force of water running down a slope can cause serious erosion problems.  It also demonstrates the effect of the force of the rainfall on erosion.

 

Objectives and Benchmarks:

This lab will show students the effects of erosion on a slope.  At the end of this lesson the students will be able to discuss the importance of preventing erosion.  They will also be able to describe several factors that lead to increased erosion.

 

Materials:

4 Cafeteria Trays                Sod            Loose Dirt           

Watering Can with Sprinkler Spout            One-Liter Container

2 Tablespoons Food Coloring

           

Advanced Preparation:

Cut two squares of sod to fit across the top of the cafeteria trays.

 

Procedure:

This lab works best as a demonstration with class participation.  First put the sod in the top of the tray.  Have a student pour water over the sod using the watering can to simulate rain.  Observe the runoff that ends in the bottom of the tray.  Repeat this procedure using the loose dirt.  Observe the runoff and compare the runoff from the sod to that of the loose dirt.  Repeat the procedure but increase the angle of the tray.  Observe the differences and make any comparisons and contrasts.  Next, use a one-liter container to pour water onto the sod or loose dirt instead of the watering can.  Repeat the steps from above.  Pour the food coloring onto the sod and then use the watering can to simulate rain.  See the effects of dumping chemicals onto the earth's surface.

 

Things to Consider:

What effect did the grass have on the erosion?

What effect did the slope have on erosion?

What effect did the force of water have on erosion?

 

Possible Integration:

This activity can be integrated with English and the students can write a report on erosion in different parts of the world.