Soil Composition and Functions

The video tutorial covers the definition and types of soil, including sand, silt, and clay, and their particle sizes. It explains soil horizons and essential nutrients required for plant growth. The functions of soil in the ecosystem are discussed, along with important soil vocabulary. The presentation concludes with acknowledgments.

Which type of soil has the largest particle size?

• Gravel

• Silt

• Clay

• Sand

What is the size range of silt particles?

• 2 mm to 5 mm

• 0.05 mm to 2 mm

• Less than 0.002 mm

• 0.02 mm to 0.05 mm

What is the primary characteristic of the 'O' horizon in soil?

• Rich in minerals

• Made up of deposited sediments

• Composed of bedrock

• Contains undecayed organic materials

Which soil horizon is known for being rich in minerals?

• A horizon

• O horizon

• B horizon

• R horizon

Which nutrient category includes carbon, hydrogen, and oxygen?

• Micronutrients

• Air and water category

• Macronutrients

• Solid soils category

Which of the following is a micronutrient essential for plants?

• Calcium

• Iron

• Phosphorus

• Nitrogen

What is one of the key functions of soil in the ecosystem?

• Acts as a primary source of oxygen

• Serves as a medium for plant growth

• Provides energy for animals

• Regulates atmospheric pressure

Which term describes a mixture of sand, silt, and clay that is ideal for plant growth?

• Subsoil

• Topsoil

• Humus

• Loam

What is the role of humus in soil?

• Forms the bedrock layer

• Supplies nutrients to plants

• Acts as a water reservoir

• Provides structure to soil

Which layer of soil is primarily composed of rock?

• Organic layer

• Bedrock

• Subsoil

• Topsoil