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

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

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

10. Fundamental Components of Soil

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

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

13. Components of Soil Liquid ~ 25% 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 Organic: decomposed plant and animal material Mineral: Sands, silts, clays, oxides (Al and Fe) • reactivity • Water movement/retention

15. Organic

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

17. Vegetative Influences Forested Deciduous Coniferous Grasses

18. Organic Matter Generalizations • 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

19. Mineral

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

22. Soil Formation and Morphology Basics

23. Processes Additions Losses Translocations Transformations

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

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

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

27. Soil Master Horizons

28. Master Horizons [ A horizon

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

30. Master Horizons A horizon [ B horizon

31. The B Horizon • 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

32. Master Horizons A horizon B horizon [ C horizon

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

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

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

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

37. The R Horizon R horizon limestone

38. The O Horizon • 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.

39. O Horizon

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

41. Soil Profiles

42. Delineating Soil Horizons

43. Criteria for Characterizing Soil Horizons • Color • Texture • Density • Structure • Organic matter • Mineralogy • Chemistry

44. Soil Physical Properties

45. Soil Color

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

47. Soil Color Determination

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

49. Soil Color

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