Soils Up Close: The Soil Profile and Horizon Characteristics

1. Soils Up Close:The Soil Profile and Horizon Characteristics

2. I. The Soil Profile A. Profiles vs. Pedons Soil Profile: a two-dimensional body, commonly studied in artificial cuts. Soil Pedon: a three-dimensional body, with the same thickness as a profile, but with a surface area that ranges between 1 and 100 square meters. From: Birkeland, 1999

3. I. The Soil Profile B. Gaining the 3rd Dimension

4. I. The Soil Profile B. Gaining the 3rd Dimension • Roadcut/Construction Excavation

5. I. The Soil Profile B. Gaining the 3rd Dimension 2. Pit Excavation

6. I. The Soil Profile B. Gaining the 3rd Dimension 3. Soils Augering

7. The Soil Profile C. Major Components of Soil

8. The Soil Profile C. Major Components of Soil Mineral Matter 45% Organic Matter 05% Water 25% Air 25%

9. II. Soil Profile Horizons A. Master Horizons

10. I. The Soil ProfileA. Master Horizons……OAEBCR Solum Solum: Consists of the surface and subsoil layers that have undergone the same soil forming conditions. Epipedon: “over the soil"; the uppermost layer of soil that serves as the diagnostic horizon.

12. E R

17. E

18. E

20. “Zone of Leaching” Or “Zone of Eluviation”

21. Zone of illuviaton

22. Diagnostic properties (B horizon) • Thickness • Color • Texture • Structure

24. R

25. II. The Soil Profile C. Subhorizons

27. Subhorizons

28. Subhorizons

29. Subhorizons

30. Subhorizons

31. III. Soil Profile Characteristics

33. III. Soil Profile Characteristics A. Texture

34. III. Soil Profile Characteristics A. Texture • Major categories Boulder Stones Cobble Gravel Sand Silt Clay 600 mm 250 mm 76 mm 2 mm 0.05 mm 0.002 mm

37. < 0.002 mm Texture 0.062 to 0.05 mm 2.0 to 0.05 mm

38. < 0.002 mm Texture Common in B Horizons Common in A Horizons 0.05 to 0.002 mm 2.0 to 0.05 mm Common in A Horizons over Granites

39. III. Soil Profile Characteristics A. Texture 2. Importance of Texture in Soils Work

40. III. Soil Profile Characteristics A. Texture 2. Importance of Texture in Soils Work • Reflects character of Parent Material

41. III. Soil Profile Characteristics A. Texture 2. Importance of Texture in Soils Work • Reflects character of Parent Material • Affects processes within the soil

42. III. Soil Profile Characteristics A. Texture 2. Importance of Texture in Soils Work • Reflects character of Parent Material • Affects processes within the soil • Degree of horizon development (fine vs. coarse-grained soils) • Drainage properties • Engineering properties

43. III. Soil Profile Characteristics A. Texture 2. Importance of Texture in Soils Work • Reflects character of Parent Material • Affects processes within the soil • Degree of horizon development • Drainage properties • Engineering properties • Degree of chemical reactivity • Water retention

44. III. Soil Profile Characteristics A. Texture 2. Importance of Texture in Soils Work • Reflects character of Parent Material • Affects processes within the soil • Degree of horizon development • Drainage properties • Engineering properties • Degree of chemical reactivity • Water retention • Erositivity • Tilth

45. III. Soil Profile Characteristics A. Texture 3. Determining Texture

46. Qualitative Methods

47. Qualitative Methods

48. III. Soil Profile Characteristics A. Texture 3. Determining Texture

49. III. Soil Profile Characteristics A. Texture 3. Determining Texture

50. 20 ml pipette