1. 5.2 Soil

2. Regolith
• The layer of rock and mineral fragments that
nearly everywhere covers Earth’s surface

3. Soil
• A combination of mineral and organic
matter, water, and air.

4. Soil Horizon
• A layer of soil that has identifiable
characteristics produced by chemical
weathering and other soil-forming processes

5. Soil Profile
• A vertical section through a soil showing its
succession of horizons and the underlying
parent material.

6. Pedalfer
• Soil of humid regions characterized by the
accumulation of iron oxides and aluminum-
rich clays in the B horizons.

7. pedocal
• Soil associated with drier regions and
characterized by an accumulation of calcium
carbonate in the upper horizons

8. laterite
• A red, highly leached soil type found in the
tropics that is rich in oxides of iron and
aluminum.

9. Key Concept
• Soil is the part of the regolith that supports
the growth of plants

10. Key Concept
• Soil has four major components: mineral
matter, or broken-down rock; organic
matter, or humus, which is the decayed
remains of organisms; water; and air.

11. Key Concept
• The most important factors in soil formation
are parent material, time, climate, and slope.

12. Key Concept
• Soil varies in
composition, texture, structure, and color at
different depths.

13. Key Concept
• Three common types of soil are
pedalfer, pedocal, and laterite.

14. Key Concept
• However, human activities that remove
natural vegetation, such as
farming, logging, and construction, have
greatly accelerated erosion.