1. Chapter 12
Soils

2. Soils
Although soil is a part of the lithosphere – the land, we will cover it now with a focus on the soil/water interaction.
Forming Factors
Geologic
Climatic
Topographic
Biological
Chronological
Components
Inorganic
Organic
Soil Air & Water
Properties
Color
Texture
Structure
Moisture
Aroma

3. Zone of Plant Growth & Interface
Soil is a thin surface layer that of mineral and organic material that is capable of supporting plants
It is characterized by its ability to produce and store plant nutrients due to water, air, sunlight, rocks, plants, & animals
It functions as an inter-face between atmosphere, lithosphere, hydrosphere, and biosphere.

4. Soil and Regolith Soil is the topmost layer of the regolith
Average depth 6 in.
Composition:
Weathered mineral particles
Decaying organic matter
Living organisms
Gases
Liquid solutions

5. Weathering
Ocean worked rock - 8 feet high – Tumbo Island

6. Soil-Forming Factors There are five soil-forming factors: Geologic
Climatic
Topographic
Biological
Chronological

7. Soil Development

8. Geologic Factor Parent material
Disintegrated, decomposed near Earth’s surface
Influences characteristics of soil
Over time, significance of parent material diminishes
Large particles=porous soil
Minute particles=fine textured soil

9. Climatic Factor Temperature Moisture
Processes accelerated by higher temps & moisture
Slowed down by low temp and lack of moisture
Moisture moves materials around – vertically and horizontally

10. Topographic Factor: Erosion
Slope and drainage enable:
Lowering of bottom layer Lowering of top layer-erosion

11. Topographic Factor: Slope
Flat land = slow erosion = deepest soils Steep slope = fast erosion = thin soil

12. Biological Factor: Animals
Soil= ½ mineral ½ air and water
Living and dead plants, animals make it more than dirt

13. Chronological Factor Develops from sediments quickly
From bedrock slowly
Warm moist environment promotes soil development

14. Soil Components
Inorganic Materials
Organic Matter
Soil Air
Soil Water

15. Pore Spaces

16. Soil Water

17. Forms of Soil Moisture

18. Eluviation and Illuviation

19. Idealized Soil Profile