1. Anyone who did not attend Lecture I, see me after class for materials and course basics

2. Soil Basics

3. Arcanum Mysterious knowledge known only to the initiated ?

4. What is Soil?

5. It is not Dirt

6. What is Soil? …unconsolidated surficial material Short-sighted Engineer, 1985

7. What is Soil? A dynamic natural body composed of mineral and organic materials and living forms in which plants grow. The collection of natural bodies occupying parts of the earth’s surface that support plants and have varying properties due to the integrated effects of climate and life acting upon geologic materials, mediated by relief (topography) and time Brady and Weil, 2000

8. Agronomist Forester Horticulturalist Engineer Environmentalist Ecologist What is Soil?

9. Medium for plant growth Regulator of water supplies Recycler of raw materials Habitat for soil organisms Engineering medium Functions of Soil

10. Fundamental Components of Soil

11. Solids Voids Avenues Storage Distribution Movement Interactive Media Minerals Organic matter Reactivity Idealized Surface Soil

12. Gases~ 25% Components of Soil Oxygen: Carbon Dioxide: Atmosphere Soil Atmosphere 21% 0.038% 5-10% 0.3-3% Microorganisms tend to reduce oxygen and enrich carbon dioxide

13. Liquid ~ 25% Components of Soil Dissolved and Suspended Constituents Nutrients Metals Salts Acids/Bases Organic Compounds Contaminants Gases Solid Phase

14. Components of Soil Mineral + Organic ~ 50% Solid soil particles and organic matter Mineral:Sands, silts, clays, oxides (Al and Fe) Organic:decomposed plant and animal material reactivity Water movement/retention

15. Organic

16. > 20% O.M.< 20% O.M. Mineral Soil Organic Soil Organic Matter 5% >50%

17. Vegetative Influences Deciduous Coniferous Grasses Forested

18. Organic Matter Soil color – the darker the color, the more OM. Soil structure – cementing agents, fibers. Soil nutrients –organically derived (P, S, N, Ca, Mg, K). Energy sources – energy for soil organisms. Soil Water – increases water holding capacity Soil reactivity – increases chemical reactivity of soils Generalizations

19. Mineral

20. Components of Soil Mineral ~ 45% Rocks, stones, gravel, particles, aggregates Particles:primary minerals (quartz, feldspars) secondary minerals (clays, oxides) Rocks Primary MineralsSecondary Minerals Can be highly reactive

22. Soil Formation and Morphology Basics

23. Additions Losses Translocations Transformations Processes

24. Soil as a Natural Body Parent Material Bedrock Additions Losses Translocations Transformations Bedrock Differentiation

25. Soil Profile Soil Profile – 2D representation of a vertical section of soil from the surface to its deepest layers. The Essentials of Soils Differentiation of layers Is highly variable.

26. Soil Horizons Roughly parallel layers in the soil with varying composition and properties

27. Soil Master Horizons

28. Master Horizons A horizon [

29. topsoil/plow layer. Accumulates organic material Often darker than soil below. high in plant roots, biotic activity Zone of gas and water exchange The A Horizon A horizon

30. Master Horizons A horizon B horizon [

31. - Accumulates material transported from above, or forms in place. (translocation, transformation) - Zone of Illuviation (translocation). - clays, O.M., Fe/Al oxides, salts good soil structure Strong color development Potentially high reactivity B horizon The B Horizon

32. Master Horizons A horizon B horizon C horizon [

33. -Weakly altered by soil forming processes. -Closely resembles parent material C horizon The C horizon

34. Master Horizons A horizon B horizon C horizon E horizon

35. Eluviation - Zone of Eluviation The E horizon E horizon A horizon B horizon Eluviation = exit Illuviation = into Organic matter Clay Carbonates Fe, Al oxides color (Illuvial) (Elluvial)

36. Master Horizons A horizon B horizon C horizon E horizon R Horizon Florida?

37. R horizon The R Horizon limestone

38. Surface Horizon Organic horizon Non-mineral dark-colored Often called peat, muck Some are very fertile, valuable In some countries, O horizon used as fuel. The O Horizon

39. O Horizon

40. A horizon B horizon C horizon E horizon R Horizon O horizon Soil Horizons Master Horizons O organic A topsoil E elluvial B developed C parent material R bedrock O horizon A horizon B horizon E horizon

41. Soil Profiles

42. Delineating Soil Horizons

43. Criteria for Characterizing Soil Horizons ColorTextureDensityStructure Organic matter MineralogyChemistry

44. Soil Physical Properties

45. Soil Color

46. Mineralogy of the soil/parent material Relative amount of organic matter or iron Hydrology of the soil Oxygen status Soil Color Determinants

47. Soil Color Determination

48. Value Chroma Hue Munsell Soil Color dominant spectral color; related to the wavelength of light. Related to the proportions of red to yellow. related to total amount of light reflected. measure of the strength of spectral color

49. Soil Color

50. Hue = 10 YR Value = 6 Chroma = 3 Munsell Color 10 YR 6/3

52. Summary Hue dictates dominant spectral color for a given page. Low value indicates dark soil colors. (O.M.?) High chroma indicates strong color expression 10YR 3/6

53. Communication Water table depth Oxygen status Development decisions

54. Criteria for Characterizing Horizons ColorTextureDensityStructure Organic matter MineralogyChemistry