Understanding Soil Composition and Structure

The video explains the importance and composition of soil, detailing its components: minerals, organic matter, water, and air. It introduces the concept of soil profiles and horizons, describing each layer's characteristics and functions. The O horizon, or litter, contains organic debris, while the A horizon, or topsoil, is rich in organic matter and minerals. The E horizon, or eluvian layer, is where substances are leached out, and the B horizon, or subsoil, accumulates materials like clay. The C horizon consists of parent material, and the R horizon is the bedrock. The video concludes with additional resources for further learning.

What percentage of soil is composed of minerals?

• 5%

• 45%

• 15%

• 25%

Which component of soil is responsible for its organic matter?

• Decaying plants and animals

• Water

• Minerals

• Air

What does a soil profile represent?

• A horizontal layer of soil

• A type of soil horizon

• A vertical section showing different layers

• A mixture of minerals and organic matter

Which horizon is known as the litter layer?

• A Horizon

• B Horizon

• O Horizon

• C Horizon

What is the main function of decomposers in the A horizon?

• To break down organic matter

• To form bedrock

• To add minerals

• To remove water

What is the E horizon also known as?

• Parent material

• Eluvian layer

• Subsoil

• Topsoil

Which horizon is characterized by a reddish or brown color due to less humus?

• B Horizon

• O Horizon

• A Horizon

• C Horizon

What is the C horizon primarily composed of?

• Parent material

• Bedrock

• Organic matter

• Topsoil

Which horizon is referred to as the bedrock?

• B Horizon

• A Horizon

• C Horizon

• R Horizon

What type of rock can be found in the R horizon?

• Silt

• Sandstone

• Clay

• Humus