1. Soil is an important natural resource to life on earth!
III. Soil Formation
Soil is an important natural resource to life on earth!   

2. Soil is the loose covering of broken rock particles and decaying organic matter, overlying the bedrock of earth’s surface.

3. Burrowing animals, insects, bacteria, and fungi help add organic matter to soil

4. During development, soil forms in layers

5. Parent Rock
The solid bedrock from which weatherized pieces of rock first break off 

6. Residual Soil
Soil located above the parent material.

7. Transported Soil
Has been moved to a location away from its parent bedrock.

8. Soil Profiles
A soil profile is the vertical sequence of soil layers.

9. Topography
The topography of a region affects the thickness of developing soil.
In sloped areas, where runoff readily occurs, the coarser particles of soil remain on the slopes.
The smaller particles move downslope.

10. Soil Horizons
A distinct layer, or zone within a soil profile is called a soil horizon.
There are 3 major soil horizons: A, B, and C

11. Soil Types
Polar
Temperate
Desert
Tropical

12. Polar Soil Form at high latitudes (Canada, Antarctica)
Has good drainage
Shallow (only a few cm. deep)
Permafrost (frozen ground) is usually found beneath it.

14. Temperate Soil
Supports environments such as forests, grasslands, and prairies.
Lots of rainfall on this soil

16. Desert Soil
Receives low levels of precipitation. Less than 25 cm per year.
Has high levels of salts, light colored, and coarse
Supports only a limited amount of vegetation
Little or no organic matter
Very thin A horizon
Has abundant nutrients

18. Tropical Soil Found in High temperatures Heavy rainfall
Weathered and infertile soil 

20. Soil Textures
Particles of soil are classified according to size as being: clay, silt, or sand.
Clay is the smallest
Sand is the largest
Look at pg. 172 in book at Table 7-2 and pg. 173 Figure 7-24. 

21. Soil Fertility
Is the measure of how well a soil can support the growth of plants.

22. Factors that affect soil fertility are:
Availability of minerals and nutrients
Number of microorganisms present
Amount of precipitation available
Topography
The level of acidity

23. Soil Color
1. A soil’s composition and the climate in which it develops are main factors that determine the soil color.
2. Topsoil is usually dark-colored because it is rich in humus.

24. Soil Color Continued.. Color cannot predict fertility.
Red and yellow soils may be the result of oxidation of iron and minerals.
Grayish or bluish soils are common in poorly drained regions where soils are constantly wet and lack oxygen.