4.2 Soil Formation & Erosion

Question 1

Soil Horizons

Answer 1

Soil horizons are distinct layers of soil that form as a result of various processes such as weathering, organic matter accumulation, and leaching. Each horizon has unique characteristics that influence the movement of water, nutrients, and organisms within the soil.

Think of soil horizons like layers in a cake. Just as each layer contributes to the overall taste and texture of the cake, each soil horizon plays a role in determining the fertility and composition of the soil.

Question 2

O Horizon (Humus)

Answer 2

Surface litter, like leaves and other decaying matter

Question 3

A Horizon (Topsoil)

Answer 3

The A Horizon contains a mixture of organic materials with minerals

Question 4

E Horizon (Eluviated)

Answer 4

The E Horizon, also known as the eluviation horizon, is a soil layer that is characterized by the leaching or removal of minerals and nutrients due to water movement. It is typically found below the O Horizon and above the B Horizon.

Imagine you have a bowl of cereal with milk. As you eat the cereal, some of the milk gets absorbed into the cereal, leaving behind a drier layer at the top. This drier layer represents the E Horizon where minerals and nutrients have been washed away.

Question 5

B Horizon (Subsoil)

Answer 5

The B Horizon, also known as subsoil, is a soil layer that accumulates minerals and nutrients leached from upper layers. It often contains clay particles and has less organic matter compared to the A horizon.

Think of your bedroom closet. You have shelves where you store items like books or clothes. Over time, dust settles on these shelves representing accumulated minerals in the B horizon.

Question 6

C Horizon (Parent Material)

Answer 6

The C Horizon, also known as parent material, is an unweathered soil layer composed of rock fragments and partially broken-down minerals. It serves as the source for the development of upper soil horizons.

Imagine you have a bag of mixed nuts. The whole nuts represent the rock fragments in the C horizon that haven’t undergone much weathering yet.

Question 7

Bedrock

Answer 7

Solid rock that lies beneath the parent material and soil

Question 8

Water Quality

Answer 8

Water quality refers to the chemical, physical, biological, and radiological characteristics of water that determine its suitability for specific uses. It encompasses factors like pH levels, dissolved oxygen content, presence of pollutants or contaminants, and overall ecological health.

Question 9

Erosion

Answer 9

Erosion is the geological process in which earthen materials are worn away and transported by natural forces such as wind or water. A similar process, weathering, breaks down or dissolves rock, but does not involve movement.

Question 10

Weathering

Answer 10

Weathering describes the breaking down or dissolving of rocks and minerals on the surface of the Earth. Water, ice, acids, salts, plants, animals, and changes in temperature are all agents of weathering.