Lesson 6.01 Soil Composition

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1. Which of the following components of soil provides the physical support of plants that grow in it?
   1. inorganic material
   2. bedrock
   3. sand

   Answer: a. inorganic material - Inorganic material is provided by the parent material and makes up about 45% of the typical soil.

2. What is a layer of soil called?
   1. inorganic material
   2. soil profile
   3. soil horizon
   4. soil pH

   Answer: c. soil horizon - Horizons in the soil have different characteristics based on their location.

3. Which of the following is important for people in agriculture and construction to know about a regions soil?
   1. inorganic material
   2. soil profile
   3. soil horizon
   4. soil pH

   Answer: b. soil profile - A soil profile would be beneficial to agriculture and construction because it shows all the soil layers and how they are made up.

4. Which soil texture is composed of the largest particles?
   1. sand
   2. clay

   Answer: a. sand - Sandy soil has a gritty feel and is made up of larger sized particles.

5. Which soil horizon in a typical soil is nearest the top and has varying degrees of decomposing organic material?
   1. sand
   2. clay
   3. Horizon O

   Answer: c. Horizon O - This layer is the top layer that is very thin and dark.

6. Which of the following properties of soil is a chemical property/characteristic?
   1. sand
   2. clay
   3. Horizon O
   4. soil pH

   Answer: d. soil pH - Soil pH is a chemical property that describes how acidic of alkaline the soil is.

7. Which of the following soil types/textures has the greatest porosity?
   1. sand
   2. clay
   3. bedrock

   Answer: b. clay - Clay soil has the smallest particles with the most pores; however the pores are very small.

8. Which of the following soil types allows water to pass/infiltrate through it the quickest?
   1. sand
   2. clay
   3. bedrock

   Answer: a. sand - The pores in sandy soil are the largest of all soil types and lets water pass down or infiltrate through it at a faster rate than the other soils.

9. Which of the following is located below the C horizon and is the source of parent material for the soil?
   1. sand
   2. clay
   3. bedrock

   Answer: c. bedrock - Bedrock is solid rock that is either igneous, sedimentary, or metamorphic rock.