4.3 Soil Composition and Properties

Describe similarities and differences between properties of different soil types.

• Water holding capacity—the total amount of water soil can hold—varies with different soil types. Water retention contributes to land productivity and fertility of soils.
• The particle size and composition of each soil horizon can affect the porosity, permeability, and fertility of the soil.
• There are a variety of methods to test the chemical, physical, and biological properties of soil that can aid in a variety of decisions, such as irrigation and fertilizer requirements.
• A soil texture triangle is a diagram that allows for the identification and comparison of soil types based on their percentage of clay, silt, and sand.
• Enduring understanding ERT-4: Earth’s systems interact, resulting in a state of balance over time.