Activities

1. What are the components of soil?
   
   
2. Describe how soil forms and becomes fertile.

3. What affects the color of the soil?
   
   
4. What affects the texture of soil?
   
   
5. How does rainfall affect soil fertility?

6. Construct a paragraph that answers the following:

• • What is soil erosion?
  • What factors affect soil erosion?
  • What are dangers of soil erosion?

Answer Key/Rubric

1. Soil is made of weathered rock, water, air, and the remains of living organisms.
   
   
2. When rocks break down into smaller pieces, mosses and other basic plants begin to form.  When they grow, they break down the rock even more, releasing minerals.  Soil begins to form, and continues to as weathering continues. Larger plants have the ability to grow since dead plant and animal material provide nutrients for the soil. The more nutrients in the soil, the more fertile the soil.

3. Soil’s color is affected by the minerals that make up the type of rock it is formed from.  For example, iron-rich rocks produce a reddish soil.  Color is also affected by the amount of organic matter in the soil.  The more organic matter, the darker the soil.
   
   
4. Texture can be affected by the minerals present in the rock that makes up the soil. Pieces of rock that have not been weathered as much make for a coarser soil.  Texture can also be affected by climate.  Weathering occurs faster in area with more rainfall, which usually results in smaller rock remains.  In dry climates such as deserts, the weathering process is slow.
   
   
5. In warm climates with a lot of rainfall, the minerals are drained into the subsoil. The topsoil therefore lacks minerals, and is not very fertile.  In dry climates, since there is little rainfall, the water evaporates quickly, and the minerals that were dissolved in the water collect at the soil’s surface (not into the subsoil).

6. Acceptable responses must include:

• Explanation of soil erosion
• Factors that effect of soil erosion
• Dangers of soil erosion

Sample response: Soil erosion is the transferring of soil from one place to another by agents such as wind and water.  If soil is too dry, the wind can blow it around, removing minerals from the soil, affecting the growth of plants due to lack of nutrients.  The shape of a land can also affect soil erosion due to water.  Moving water has the ability to wash away the nutrients in soil.  If water is moving down a mountain, for example, the nutrients in the soil are carried with the water. The soil on the tops of hills and mountains therefore is less fertile than the flat land beneath it.

Soil erosion can be dangerous because if the soil is not fertile, then there is no soil to grow plants in.  If there are no plants, this can affect the food that people and animals are able to eat.  Another danger is that excessive dust can be damaging.  It can affect one’s health, breathing and take a toll on machinery (see the 1930s Dust Bowl).