Exploring The Five Layers Of Soil And Their Importance

This video lesson explores the five layers of soil: O-horizon (organic layer), A-horizon (topsoil), B-horizon (subsoil), C-horizon (parent rock), and R-horizon (bedrock). Each layer is described in terms of its composition, characteristics, and role in supporting plant life. The O-horizon is rich in organic matter, the A-horizon is ideal for seed growth, the B-horizon contains mineral salts, the C-horizon consists of weathered rock, and the R-horizon is made of unweathered rock.

How many layers of soil are there?

• Five

• Four

• Three

• Six

What is the main component of the O-horizon?

• Water

• Unweathered rock

• Organic matter

• Mineral salts

Which layer is known for being rich in humus and minerals?

• O-horizon

• A-horizon

• R-horizon

• B-horizon

What type of organisms are commonly found in the A-horizon?

• Birds

• Large mammals

• Fish

• Microorganisms like bacteria and fungi

Which layer is more solid and less porous, making it suitable for the roots of big plants?

• O-horizon

• B-horizon

• C-horizon

• A-horizon

What is the C-horizon primarily composed of?

• Organic matter

• Weathered rock material

• Mineral salts

• Unweathered rock

Why is the C-horizon referred to as the parent rock?

• It is the topmost layer

• It is rich in humus

• It contains the most minerals

• The layers above originate from it

What is the R-horizon composed of?

• Weathered rock

• Organic matter

• Unweathered parent rock

• Mineral salts