1. Environmental science
Soil
Environmental science

2. Pre Test
What is the difference between Soil Profile and Soil Horizons? 01
Which horizon accumulates organics and clays by the movement of water. 02
What are 5 soil forming factors 03
What horizons are considered Master horizons 04

3. Soil Forming Factors Weathering of minerals i.e. parent material
Climate
Biota (living plants/animals and the decomposition of organic matter)
Typography
Time
Soil and Our Environment p , Text p. 292

4. Weathering Breakdown of parent material in soil formation by physical and chemical breakdown
Mechanical Weathering
Freezing and Thawing (ice expansion)
Uneven Heating
Abrasion – ice, water and wind
Shrinking Swelling
Root activity
(Cornell University)
Chemical Weathering
Oxidation
Hydrolysis
Acidic rain

5. Climate Dry, cold climates Warm wet climates Slower Soil Formation
Slower weathering (depending on parent material)
Slower decomposition
Warm wet climates
Faster weathering (depending on parent material)
Faster decomposition
Text, p. 292
Slower Soil Formation
Faster Soil Formation

6. Biota Interaction of soil organisms such as plants, animals, microbes
Burrowing animals (gophers, earthworms, ants, etc.)
help mix nutrients
Plant Roots
some can reinstate soil nutrients
Breakdown parent material
Microorganisms (bacteria, fungi, protists)
Decompose organic matter
Text p 292, Soils and Our Environment p. 20

7. Typography The lay of the land (climate has an effect) Steep hillsides
Developing soil profiles
Nutrients are unable to be leached to lower horizons
Aspect – SW slopes receive more sun causing dry/arid
Rolling Hills
Deep soil profiles because water leaches materials to lower horizons
Good A,O Horizons
Valleys or Depressions
Rich organic soils
Salt marshes
Soils in Our Environment p. 22, Text 297

8. Time It takes a minimum of 1 year to develop 1” of top soil
Depends on Climate, Parent Material, Organisms, Topography
Effects the amount of time the soil is formed.
NRCS Soil Formation