1. Soil forms when weathered parent material interacts with environment.
Soil Formation
Soil forms when weathered parent material interacts with environment.

2. Soil environment includes:
Climate and weather
Animals
Microbes
Human use
Hazards ( natural and unnatural )
Topographical relief

3. rates of soil formation
Slow Fast
~ 1 cm/1000 yr ~ 30cm/50yr

4. Hans Jenny
1941: soil is open system, properties are functionally related; system changes when property(ies) change(s).
Jenny’s CLORPT equation
s = ƒ (cl, o, r, p, t)

5. 1. CLIMATE 2. ORGANISMS 3. RELIEF 4. PARENT MATERIAL 5. TIME

6. 1. CLIMATE …determines speed, character of soil development:
type and rate of weathering
living organisms and plants found in an area

7. components of climate :
1. Temperature
-for every 10°C , biochemical rxn rates 2X
2. Effective precipitation
(water that moves through entire soil column, including regolith)
-depth of water = depth of weathering
-water moves soluble & suspended materials

8. (Fig. 2.15)

9. Effective precipitation
-a) seasonal distribution -b) temperature, evaporation -c) topography -d)permeability

10. a) Seasonal distribution of precipitation:
Location B
600 mm/yr
Location A
600 mm/yr
100mm
50mm
6 rainy months only
Every month

12. b) Temperature and evaporation:
Location A
hot
Location B
cool
High
evapotranspiration
Low
evapotranspiration
600 mm
600 mm
Lower effective ppt
Higher effective ppt

13. Topography:
concave or
bottom of slope
(receiving)
level
slope

14. Permeability:

15. 2. Organisms plant and animal
(Living plants and animals on and in soil)
-type of vegetation influences soil type
-base pumping
-sources of organic matter
-nutrient recycling
-vegetation prevents erosion

16. Type of vegetation influences soil type

17. Base pumping
Deciduous trees are more effective base pumpers than conifers .
-needles are hard to
break down
-basic cations leach
away: soil is acidic
-deciduous litter is easy to break down
-cations (bases) are released so surface soils are not acidic

18. Macroanimals (insects, mammals, gastropods, earthworms)
mix, bind soil; create channels for air, water

19. crotovinas

20. Macroanimals (insects, mammals, gastropods, earthworms)
mix, bind soil; create channels for air, water
Microanimals (nematodes, protozoa)

21. Macroanimals (insects, mammals, gastropods, earthworms)
mix, bind soil; create channels for air, water
Microanimals (nematodes, protozoa)
Macroplants (the green plants)
provide organic matter, roots create channels, adsorb nutrients, release CO2, stabilize, protect from erosion

22. Macroanimals (insects, mammals, gastropods, earthworms)
mix, bind soil; create channels for air, water
Microanimals (nematodes, protozoa)
Macroplants (the green plants)
provide organic matter, roots create channels, adsorb nutrients, release CO2, stabilize, protect from erosion
Micro “plants” (fungi, bacteria, actinomycetes, algae)
decomposers

23. 3. Relief/Topography
important for rate of runoff, erosion, drainage

25. Flat valley floors and flat ridge tops: soil accumulates; (deepening>removal)
Slopes: (removal> deepening)

26. Vertical Zonation
soils, climate, vegetation change with elevation

27. 4. Parent Material
Determines texture, types of weathering, mineral make-up

28. weathering
Physical (Mechanical): disintegration of parent material; increases surface area:
surface area increases by same factor as particle size decreases
Chemical (Biogeochemical) : primary minerals are broken down and secondary minerals are formed

31. Chemical (biogeochemical):
Physical:
1. Freeze/thaw
2. Exfoliation
3. Abrasion
4. Salt wedging
Chemical (biogeochemical):
1. Hydrolysis: minerals react with H2O
H+ replace soluble parts; OH- combine with mineral cations
2. Hydration: mineral combines with H2O
3. Oxidation: mineral combines with O2 (lose electron)
Reduction: loss of O2 (gain electron)
4. Carbonation: oxides combine with acids to make carbonates
5. Complexation: organic acids form organic complexes with metal cations

33. Freeze / Thaw

36. Chemical (biogeochemical):
Physical:
1. Freeze/thaw
2. Exfoliation
3. Abrasion
4. Salt wedging
Chemical (biogeochemical):
1. Hydrolysis: minerals react with H2O
H+ replace soluble parts; OH- combine with mineral cations
2. Hydration: mineral combines with H2O
3. Oxidation: mineral combines with O2 (lose electron)
Reduction: loss of O2 (gain electron)
4. Carbonation: oxides combine with acids to make carbonates
5. Complexation: organic acids form organic complexes with metal cations

37. 2. Exfoliation

40. Chemical (biogeochemical):
Physical:
1. Freeze/thaw
2. Exfoliation
3. Abrasion
4. Salt wedging
Chemical (biogeochemical):
1. Hydrolysis: minerals react with H2O
H+ replace soluble parts; OH- combine with mineral cations
2. Hydration: mineral combines with H2O
3. Oxidation: mineral combines with O2 (lose electron)
Reduction: loss of O2 (gain electron)
4. Carbonation: oxides combine with acids to make carbonates
5. Complexation: organic acids form organic complexes with metal cations

41. 3. Abrasion (wind, water, ice)

43. water

44. ice

45. Chemical (biogeochemical):
Physical:
1. Freeze/thaw
2. Exfoliation
3. Abrasion
4. Salt wedging
Chemical (biogeochemical):
1. Hydrolysis: minerals react with H2O
H+ replace soluble parts; OH- combine with mineral cations
2. Hydration: mineral combines with H2O
3. Oxidation: mineral combines with O2 (lose electron)
Reduction: loss of O2 (gain electron)
4. Carbonation: oxides combine with acids to make carbonates
5. Complexation: organic acids form organic complexes with metal cations

46. 4. Salt Wedging

47. 5. Time
Amount of time soil has been exposed to weathering and soil forming processes influences soil properties.
Jenny’s staircase
Ohio/Ky.

49. 4 soil forming processes: (pedogenic)
Transformation

51. 4 soil forming processes:
Transformation
Translocation

53. 4 soil forming processes:
Transformation
Translocation
Addition

55. 4 soil forming processes:
Transformation
Translocation
Addition
Loss