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Soil--Lithosphere. Mrs. B-Z. Soil--definition. Complex mixture of eroded rock, mineral nutrients, decaying organic matter, water, air, and billions of living organisms. Indirect resources from soil. Provides us with wood, paper, fiber, and medicines. Direct benefits of soil. Purifies water

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  1. Soil--Lithosphere Mrs. B-Z

  2. Soil--definition • Complex mixture of eroded rock, mineral nutrients, decaying organic matter, water, air, and billions of living organisms

  3. Indirect resources from soil • Provides us with wood, paper, fiber, and medicines

  4. Direct benefits of soil • Purifies water • Decomposes biodegradable waste

  5. We Study Soil Because It’s A(n) Great integrator Medium of crop production Snapshot of geologic, climatic, biological, and human history Producer and absorber of gases (CO2 and others) Waste decomposer Medium for plant growth Source material for construction, medicine, art, etc. Medium of heat and water storage Filter of water and wastes Home to organisms (plants, animals and others) Essential natural resource

  6. Hydrologic Cycle and the Soil Soil Properties that are part of the hydrologic cycle. Color Moisture Temperature Structure pH Texture Horizon Depths Bulk Density

  7. Soil Forming Factors Biota Parent Material Topography Climate (The first four factors over) Time These five factors work together to create a unique soil profile made of layers called horizons.

  8. Soil Characterization • Ways to Describe soil: • Zones or Layers of Soil • Material contained in Soil • Soil Texture • Soil Structure • Soil Color • Soil Permeability • Soil pH

  9. Soil horizons • Zones of mature soil • layers

  10. Finding and Describing Horizons Soil Pit Technique First, obtain permission to dig a pit. Obey any and all safety precautions requested, and ask about power and water lines. Arid climate soil in New Mexico, USA Forest soil in Florida, USA

  11. Soil profile • Cross sectional view of the horizons

  12. Soil Profile Comparison Forest soil in Florida, USA Forest soil in Tallinn, Estonia Soil profiles in different geographic regions will be similar if the five soil forming factors act on those soils in the same way.

  13. Humus • Partially decomposed matter found in top soil • Organic layer

  14. A horizon • Top-most layer • Top soil

  15. B-horizon • Subsoil • Soil’s inorganic material broken down • Clay, sand, silt, and gravel

  16. C horizon • Parent material • Usually bedrock or some type of rock

  17. Soil texture • Determined by different sizes and types of minerals

  18. Horizon Properties Soil Texture (continued) To Determine Soil Texture

  19. loams • Soils with roughly equal amount of clay, sand, silt, and humus

  20. Horizon Properties Soil Texture (continued) To Determine Soil Texture

  21. Soil structure • How particles are organized and clumped together

  22. Horizon Properties Soil Structure With Structure Granular Blocky Columnar Prismatic Platy

  23. Horizon Properties Soil Structure (continued) Without Structure Single Grained Massive See hands for relative size Pencil is 19 cm

  24. Soil porosity • Measure of the volume of pores or spaces per volume of soil and average difference between spaces

  25. Soil permeability • Average size of spaces or pores

  26. Horizon Properties Soil Color Munsell Notation Hue Value Chroma

  27. Horizon Properties Soil Color (continued) 1 3 2 4

  28. Horizon Properties Soil Consistence Loose* Friable * Soils with “single grained” structure always have loose consistence. Firm Extremely Firm

  29. coin Clay (feels sticky) Horizon Properties Soil Texture Relative Size Comparison of Soil Particles barrel plate Silt (feels floury) (< 0.002 mm, USDA) (< 0.002 mm, ISSS) (0.05 - 0.002 mm, USDA) (0.02 - 0.002 mm, ISSS) Sand (feels gritty) (2.00 - 0.05 mm, USDA) (2.00 - 0.02 mm, ISSS)

  30. Horizon Properties Test For Free Carbonates This is strong effervescence.

  31. Infiltration • Downward movement of water through soil

  32. leaching • Water dissolves materials in the upper layers and the solution is carried to the lower areas

  33. pH • Acidity or alkalinity in water solutions

  34. Environmental Problems with Soil Soil Erosion Famine/Hunger

  35. Soil erosion • Movement of soil components especially surface litter and top soil • Caused by • Water • Wind • How much soil is there? http://soil.gsfc.nasa.gov/app_soil/hmsoil.htm

  36. Problems with erosion • Feed millions more people with billions metric TONS less of top soil each year • 75 billion metric tons of soil erodes every year • How long does it take for one inch of top soil to form? • http://soil.gsfc.nasa.gov/inch/soiltime.htm

  37. Soil Conservation • Reducing erosion • Restoring fertility

  38. Conservation-tillage farming • Disturbing the soil as little as possible when planting • This holds in more moisture as well.

  39. Contour Farming • Planting crops in rows according to the contour of the land

  40. Strip Cropping • Alternating a crop that needs to be in rows (like corn) with one that does not (like grass).

  41. Windbreaks • Long rows of trees are planted to partially block the wind from eroding the soil

  42. Alley Cropping • Several crops are planted in strips or alleys between trees or shrubs (wind breaks).

  43. Restoring Fertility • Organic Fertilizer—from plant and animal materials • Commercial Fertilizer—produced from minerals

  44. Crop Rotation • Corn, tobacco, and cotton deplete soil nutrients so farmers rotate these from growing in the same plot of land two seasons in a row. The next season a legume will be planted instead like barley, rye, or soybeans.

  45. How is food produced • Industrial Agriculture—uses large amounts of fossil fuels, water, commercial fertilizers and pesticides

  46. How is food produced • Plantations—industrialized in tropical, developing countries (coffee & bananas)

  47. How is food produced • Traditional—enough for yourself and your dependents • More human labor

  48. Green Vegetation • More energy is given off than was used to produce it

  49. Livestock • Three units of energy put into every unit of energy produced.

  50. World Food • Under-nutrition—enough food to survive but not the right food groups • Malnutrition—not enough food to survive

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