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OPTION - UNIT 7 GEOECOLOGY

OPTION - UNIT 7 GEOECOLOGY. THE NATURAL ENVIRONMENT. Syllabus Links - Soils. Core: 1.2 Weathering and Erosion Core: 1.7 Human Interaction Core: 2.2 Physical Processes Irish regions European Regions Continental / sub-continental region Core: 3 Fieldwork.

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OPTION - UNIT 7 GEOECOLOGY

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  1. OPTION - UNIT 7 GEOECOLOGY THE NATURAL ENVIRONMENT Revised Geography Syllabus

  2. Syllabus Links - Soils • Core: 1.2 Weathering and Erosion • Core: 1.7 Human Interaction • Core: 2.2 Physical Processes • Irish regions • European Regions • Continental / sub-continental region • Core: 3 Fieldwork Revised Geography Syllabus

  3. Syllabus Links - Biomes • Core: 2.2 Continental / sub-continental region • Elective: 4.5 Environmental Impact Revised Geography Syllabus

  4. 7.1 SOILS – Development • Weathering of Rocks in Situ • Re-deposited Weathered • Material Revised Geography Syllabus

  5. 7.1 SOILS – Development - Profiles General O Organic Layer consists of plant litter and humus Not present in cultivated fields A Topsoil consists of humus and minerals The ploughed layer B Subsoil low in organic material C Transition Area between soil and parent material consists of partially disintegrated bedrock R Bedrock Revised Geography Syllabus

  6. 7.1 SOILS – Development - Profiles Brown Earth Source ENCARTA Tropical Red Soil Revised Geography Syllabus

  7. 7.1 SOILS – Development • COMPOSITION • Mineral Matter • Organic matter • Water • Air • CHARACTERISTICS • Texture • Colour • Structure • Water Content • Organic Content • Water Retention • Etc. Revised Geography Syllabus

  8. 7.1 SOILS: Composition Revised Geography Syllabus

  9. 7.1 SOILS: Characteristics – Texture • Texture refers to the proportions of sand, silt and clay present. • Texture determines the percolation and water retention qualities of the soil which influences the ability of the soil to retain nutrients • Texture also determines how roots of plants are able to penetrate the soil Revised Geography Syllabus

  10. 7.1 SOILS: Characteristics - Texture Particle Size Clay: Less than 0.002mm Silt: 0.002 – 0.02mm Sand: 0.02 – 2.0mm Revised Geography Syllabus

  11. 7.1 SOILS: Characteristics – Determining Soil Texture 100 • Fill a screw topped clear glass jar two thirds full with soil • Add water until jar is almost full • Shake the jar for 1 minute approx. • Leave the jar to settle for 24 hours Clay 90 80 Silt 70 Fine Sand 60 50 40 30 Coarse Sand 20 10 0 Revised Geography Syllabus

  12. 7.1 SOILS: Characteristics - Texture Sample Sand 70% Clay 20% Silt 10% Revised Geography Syllabus

  13. 7.1 SOILS: Characteristics – Texture • Sandy Soils • Generally loose coarse particles easy to cultivate • Good drainage and aeration • Prone to leaching • Poor water retention makes them prone to drought • Easily eroded by water when wet and wind when dry • Silty Soils • Generally loose finer particles • Better water retention than the coarser sandy soil • Tend to lack nutrients which hinders seed germination • Easily eroded by heavy rainfall Revised Geography Syllabus

  14. 7.1 SOILS: Characteristics – Texture • Clay Soils • Very fine bonded particles • Poor drainage and aeration • Prone to water-logging • Sticky when wet • Very hard when dried out • Loam Soils • Equal proportions of sand, silt and clay • Good drainage and aeration properties • Retain nutrients and moisture • Easily cultivated Revised Geography Syllabus

  15. 7.1 SOILS: Characteristics – Structure • Structure refers to the shape and size of the solid grains of the soil • Structure determines • How easily soil is worked for agriculture • How it resists erosion • How easily air, water and living organisms can circulate through the soil Revised Geography Syllabus

  16. 7.1 SOILS: Characteristics – Structure • Single Grained Structure • Associated with sandy soils • Water, air and organisms can pass through it easily • Roots can spread out into the soil easily • Water retention is poor - Nutrient retention is poor • Prone to leaching • Vulnerable to drought Single grained Revised Geography Syllabus

  17. 7.1 SOILS: Characteristics – Structure • Crumby Structure • Associated with good agricultural land – loam soils • Water, air and organisms can pass through crumby soils easily • Roots can spread out into the soil easily • Water retention is good as it is soaked up by the crumbs of soil – Nutrient retention good Crumb : 1 - 5mm Revised Geography Syllabus

  18. 7.1 SOILS: Characteristics – Structure • Massive Structure • Usually associated with clay type soils • Water, air and organisms can not pass through this type of soil easily • Roots have difficulty penetrating the large lumps of clay • Soils are often waterlogged after periods of rain • Soil dries into hard clumps after a dry period Massive Revised Geography Syllabus

  19. 7.1 SOILS: Characteristics – pH value pH = potential Hydrogen ions pH value of 7 = neutral Revised Geography Syllabus

  20. 7.1 SOILS: Characteristics – pH value • pH is a measure of acidity or alkalinity • Low pH value = Acidic Soil • Leached by heavy rainfall - lacks calcium, nitrogen, magnesium and potassium – stunted growth • Discourages living organisms – reducing rate of plant breakdown • Formation of peat • At very low pH levels aluminium is dissolved by acids – poisonous to some plants Revised Geography Syllabus

  21. 7.1 SOILS: Characteristics – pH value • High pH value = Alkaline Soil • Develops on limestone landscapes – high concentration of calcium • Deficiency of iron and boron – distorted growth • pH 7 = Neutral Soil • Neutral or slightly acidic soil is most suitable for farming • Encourages growth of bacteria – vital for releasing nutrients from organic material Revised Geography Syllabus

  22. 7.2 SOILS – Influences Affected by: • Immediate Environment • Processes Including Human Interference Revised Geography Syllabus

  23. 7.2 SOILS – InfluencesImmediate Environment • Topography • Altitude • Slope • Aspect • Climate • Global Pattern of Soils • Parent Material • Rock type Revised Geography Syllabus

  24. 7.2 SOILS – Global Climate Types Revised Geography Syllabus

  25. 7.2 SOILS – Global Patterns Revised Geography Syllabus

  26. 7.2 SOILS – European Patterns Revised Geography Syllabus

  27. 7.2 SOILS – InfluencesImmediate Environment - Topography Horizon Formation Revised Geography Syllabus

  28. 7.2 SOILS – InfluencesProcesses incl. Human Interference Human • Over-cropping • Over-grazing • Desertification • Conservation Natural • Weathering • Soil Erosion • Leaching • Humification • Podzolisation • Laterisation • Calcification Revised Geography Syllabus

  29. 7.2 SOILS – InfluencesProcesses - Weathering Revised Geography Syllabus

  30. 7.2 SOILS – InfluencesProcesses - Erosion Revised Geography Syllabus

  31. 7.2 SOILS Influences - Processes • Humification – organic matter rots to form humus • Calcification – very little leaching allows calcium to accumulate close to the surface forming fertile soil • Salinisation – moisture is brought to the surface by capillary action, but evaporates quickly and the dissolved salts are deposited in the upper layer of soil Revised Geography Syllabus

  32. 7.2 SOILS Influences – Processes • Leaching – rainwater carries soluble minerals and organic matter down through the soil profile • Podzolisation – leaching by acidic water which can dissolve almost all the soil constituents, may leave the A Horizon infertile and grey in colour • Laterisation – leaching by non-acidic water leaves iron and aluminium close to the surface giving the soil a reddish colour • Gleying – lack of oxygen in waterlogged soils slows down the rotting process and organic matter accumulates at the top of the profile Revised Geography Syllabus

  33. 7.2 SOILS – Influences Human Interference Human • Over-cropping • Over-grazing • Desertification • Conservation Revised Geography Syllabus

  34. 7.2 SOILS – Human Interference Clearing Bush-land in Australia Revised Geography Syllabus

  35. 7.2 SOILS – Human Interference Erosion caused by raindrops on bare land Revised Geography Syllabus

  36. 7.2 SOILS – Human Interference Erosion caused by tilling dry land Revised Geography Syllabus

  37. 7.2 SOILS – Human Interference Erosion caused by wind Source: Seafriends.org.nz Revised Geography Syllabus

  38. 7.2 SOILS – Human Interference Livestock Damage Source: Seafriends.org.nz Revised Geography Syllabus

  39. 7.2 SOILS – Human Interference Soil Protection Source: Seafriends.org.nz Revised Geography Syllabus

  40. 7.2 SOILS – Human Interference Erosion caused by tilling hill slopes Source: Seafriends.org.nz Revised Geography Syllabus

  41. 7.2 SOILS – Human Interference Contour ploughing Strip cropping Source: Seafriends.org.nz Terracing Paddy (Padi) fields Revised Geography Syllabus

  42. 7.2 SOILS – Human Interference Soil Protection Source: Seafriends.org.nz Revised Geography Syllabus

  43. 7.2 SOILS – Human Interference Revised Geography Syllabus

  44. 7.2 SOILS – Human Interference Revised Geography Syllabus

  45. 7.2 SOILS – Human Interference Revised Geography Syllabus

  46. 7.2 SOILS – Human Interference Desertification– Europe Revised Geography Syllabus

  47. 7.2 SOILS – Human Interference Revised Geography Syllabus

  48. 7.3 BIOMES – World Regions Characterised by inter-relationships of: • Climate • Soils • Plants • Animals Revised Geography Syllabus

  49. 7.3 BIOMES – World Climates Types Revised Geography Syllabus

  50. 7.3 BIOMES – World Regions Revised Geography Syllabus

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