1. Soils & Biology

2. Soil

3. Soil isn’t dirt, but the accumulation of decayed material over time

4. Soil is a Fundamental Part of the Ecosystem
The living systems above and below the ground are based on the properties of the soil.

5. The Study of Soil is called Pedology
Soil—a natural body of solids, liquid, & gases, with horizons (layers) & the ability to support plants
color
texture
structure
roots
pores
other features

6. Composition of Soil by Volume
Ideal Fertile Soil
Mineral 45%
Organic Matter 5%
Ideal Fertile Soil
Water 25%
Air %

7. Classification Systems Of Soil
Texture Criterion: diameter of soil particles
Soil Texture: gravel >2 mm
sand ~2 mm
silt ~0.05 mm
clay < mm

9. Soils Perform Several Vital Functions
Sustaining plant and animal life below and above the surface
Regulating and partitioning water and solute flow
Filtering, buffering, degrading, immobilizing, and detoxifying
Storing and cycling nutrients
Providing support to structures

10. Soils Also Have Scientific Names
Like plants and animals, soils are classified
The system is called Soil Taxonomy
The highest level is the soil order (12)
The lowest level is the soil series, often a place name

11. Soil Studies Include Other Fields
Science
ecology, biology, chemistry
Social Studies
world trade, land use
Mathematics
soil loss over one hectare
History
US settlement, dust bowl
Art
soil crayons, acrylic paints

12. Soil Assessment is Also Important to Minimize Risk

16. Soils Are Alive Organism Types Roles & Benefits bacteria decomposition
fungi
protozoa
nematodes
arthropods
earthworms
Roles & Benefits
decomposition
release nutrients
create pores
stabilize soils

17. Organic Matter
microorganism
soil animal
organic manure

18. Soil pH Value The best pH value for plants is 6.5
climate: high temperatures and humidity change pH
microorganisms: bacteria
environment: acid rain

19. Soil Tests for Quality: physical, chemical, & biological

20. Physical Tests - Soil Density & Texture
Fill a graduated cylinder with ¾ water
Add 2-3 teaspoons of soil.
Shake well.
Allow to settle, and measure the relative percentages of each level - look at particle size differences – sand, silt, and clay layers.

21. Permeability Assemble filter paper, funnel, and beaker.
Add two teaspoons of dry soil.
A ml of water & start timer.
Record time elapsed when water stops dripping

22. Other Laboratory Tests Include Checks For Soil Nutrients (N, P, K) and pH.

23. Most kits based on simple extraction methods, combined with color charts for interpretation.pH
Nitrogen (NO3)
Phosphorus
Potassium

24. All Right, Lets Play in the Dirt!