Soil Science Overview

Overview of Soil Resources

• Soil is a vital natural resource that supports plant growth and is part of the regolith covering Earth’s surface.
• Regolith is composed of rock and mineral fragments.

Soil Composition

• Consists of mineral matter, water, air, and humus (organic materials).
• Humus adds crucial nutrients and improves soil structure.

Soil Formation Factors

• Parent Material: Source of weathered minerals; includes residual (from bedrock) and transported (deposited sediments).
• Time: Essential for weathering processes that form soil.
• Climate: Temperature and precipitation affect the type of weathering, whether chemical or mechanical.
• Organisms: Plants and animals contribute organic matter and influence soil properties.
• Topography: Slope affects soil quality; steep slopes often result in poorer soils, while flat areas can support richer soils.

Soil Profile

• Soil varies in composition and structure at different depths, creating distinct horizons.
• Soil profile: vertical section displaying all soil horizons; solum is the active "true soil."
• Topsoil (O and A horizons): Rich in organic material.
• Subsoil (B horizon): Contains fine clay and is known as the zone of accumulation.

Erosion and Human Impact

• Erosion is accelerated by several human activities:
  • Agricultural Depletion: Tilling loosens soil, increasing susceptibility to eroding agents like wind and rain.
  • Overgrazing Animals: Livestock can significantly reduce plant cover, leaving soil vulnerable.
  • Deforestation: Logging contributes to loss of vegetation and increases erosion.
  • Mining: Activities like strip mining disturb large areas, leading to erosion.
  • Development and Expansion: Urban growth can remove natural vegetation, worsening soil erosion.
  • Recreational Activities: Off-road vehicles and hiking can create trails that allow soil to erode.

Soil Conservation Strategies

• Agricultural Practices: Use tractors wisely to minimize soil disruption.
• Grazing Management: Limit animal access to vulnerable soil areas.
• Forestry Practices: Implement sustainable logging to protect soil stability.
• Mining Regulations: Avoid mining in high-risk erosion areas.
• Construction Guidelines: Consider natural landscapes during development to preserve soil health.
• Recreational Management: Encourage sticking to designated trails to minimize soil disturbance.

Inspirational Quote

• “The Nation that destroys its soil destroys itself.” - Franklin D. Roosevelt