fv2 - soil formation

AP Environmental Science: Unit 4 – Earth Systems & Resources

Topic: 4.2 Soil Formation and Erosion

Page 1: Soil Formation

  • Importance of Soil Formation

    • Essential for plant growth and environmental health.

    • Different soil types have varying properties and nutrients.

    • Protecting soil is crucial for ecosystem stability.

  • Process of Soil Formation

    • Parent Material: The initial material that breaks down to form soil.

    • Weathering: Gradual breakdown of parent material into smaller particles.

    • Deposition: Introduction of particles from other locations.

    • Vegetation Growth: Initial moss and small plants contribute to soil development.

    • Soil Horizons Development: Interaction of plants and organisms leads to the formation of distinct soil layers.

  • Soil Horizons

    • O Horizon (Humus): Surface litter, including decaying leaves and organic matter.

    • A Horizon (Topsoil): Mixture of organic materials and minerals, crucial for plant growth.

    • E Horizon (Eluviated): Zone of leaching where nutrients move from upper to lower horizons.

    • B Horizon (Subsoil): Accumulation zone for minerals like iron; impacts nutrient availability.

    • C Horizon: Weathered parent material located above bedrock.

    • Bedrock: Solid rock beneath the soil layers.

Page 2: Soil Erosion and Water Quality

  • Significance of Soil Protection

    • Soil is vital for environmental health and must be safeguarded.

    • Erosion can occur due to wind and water, especially in the absence of vegetation.

  • Consequences of Soil Erosion

    • Historical example: The Dust Bowl in the US.

    • Erosion leads to loss of fertile topsoil, hindering plant growth.

    • Impacts water quality by reducing soil's ability to filter pollutants.

  • Role of Soil in Water Quality

    • Soil, with vegetation, filters water, ensuring cleaner water supplies.

    • Lack of soil and vegetation can lead to unfiltered water with higher pollutant levels.

Page 3: Key Terms to Review

  • C Horizon: Layer of weathered parent material, located below the B horizon and above bedrock.

  • Soil Erosion: Movement of soil from one location to another due to natural forces, leading to loss of fertile topsoil.

  • Soil Horizons: Distinct layers within soil profiles with varying physical and chemical properties, formed through weathering and organic matter accumulation.

  • Water Quality: Refers to the characteristics of water in relation to its suitability for various purposes, including drinking and supporting aquatic life. Good water quality is essential for ecosystem health and human