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formation, human interactions, biology, and natural disasters

Soils of Australasia. formation, human interactions, biology, and natural disasters. By Kate Edwards, Tyler Huntley, Kerry Malm and Brian Murtaugh. Introduction. What is Australasia Wide range of soil formation and orders Specific soil formations in New Zealand. Introduction.

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formation, human interactions, biology, and natural disasters

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  1. Soils of Australasia formation, human interactions, biology, and natural disasters By Kate Edwards, Tyler Huntley, Kerry Malm and Brian Murtaugh

  2. Introduction • What is Australasia • Wide range of soil formation and orders • Specific soil formations in New Zealand

  3. Introduction • Acidic soils in Australia • Dipterocarp forests throughout the region • Natural Disasters in Indonesia

  4. The Formation of Raw Volcanic Soil in New Zealand

  5. Tongariro Volcanic Center • Located on New Zealand’s North Island. • Raw volcanic soil dominates the landscape which is formed in tephra also know as volcanic ash.

  6. Time and Parent Material • Time: Raw volcanic soils are a very heterogeneous group of soils and are extremely young. • Parent Material: Tephras of rhyolite, dacite and andesite

  7. Climate and Topography • Climate: Cold and high rainfalls. • Topography: Raw volcanic soil forms in the vicinity of the source volcano

  8. Biota • Organisms: Most soil animals and micro-organisms are concentrated in the topsoil. • Plant Life: Vegetation rapidly recovers on volcanic soils.

  9. Profile Characteristics • A horizon: is dark in color • B horizon:10-15cm thick • C horizon: is pale yellow-brown

  10. Distinguishing features of Raw Volcanic Soils • Naturally low levels of organic matter • Generally coarse in texture • Weakly weathered • Highly susceptible to erosion • Low bulk density • Well drained, very high macroporosity

  11. Acidic Soils of Australia Tyler Huntley

  12. Acidic Sulfate • Where: SE SW Australia • Acid Subsoils 23 million hectares in Aus. • 1/3 of Aussi covered • Acid sulfate soils once made up the sea floor, • Geologically • pH levels

  13. Agricultural • Increase in acidification • Soil nutrient uptake

  14. Construction • corrode metal pipes and dissolve concrete. • foundations of buildings

  15. Surface Water • Run-off • Consequences

  16. Prevention • Identifying them • Liming • Loss of crop production

  17. Lowland Dipterocarp forests Soil associations

  18. General Background • Where: South East Asia • Climate: very warm temperatures • Growth: year round • Use: timber industry, land degradation issues • Stand characteristics: uneven aged, multi-layered • Soils: strongly acidic, infertile, vulnerable to surface erosion

  19. Types of Soils • Ultisols – most common in SE Asia • Inceptisols • Very steep slopes • Oxisols • Characterized by • Morphology • Physiochemical properties • Clay mineralogy

  20. Soil Textures • Primary factor for vertical distribution and storage of C, N, and P • Coarse - clay content <35% • Thicker A and E horizons • More roots and animals • Larger volume of coarse pores • Fine – clay content >50% • Mostly kaolinite

  21. Soil Horizons • Typically A, Ag, Eg, E, Bt or Btg, Bg & C • No O layer • termites • A Horizon • 5 cm thick • Grayish with mottles edged with thin layers of iron oxide

  22. Soil Horizons • E Horizon • 3-60 cm thick • Grayish and rust colored mottles • Clay coated in finer soils • Lower limit of major root penetration and animals • B Horizon • Argillic (shallower in fine soils) • C Horizon

  23. Upper Horizons:Mechanical composition, bulk density and porosity • Clay eluviation and illuviation in every soil • Usually in fines • Bulk density increases with depth • Higher % coarse pores at surface • Higher % total pore space at surface • Water holding capacity correlated with total porosity

  24. Upper Horizons:Nutrient Cycling • Highest storage of total C, N and P in the 0-150 cm of soil • Increase with amount of clay • Same with available N • Sandy soils • Large amt of C, not N • Exchangeable Mg and K correlated with clay • AMOUNTS STILL VARY GREATLY, EVEN WITH SIMILAR CLIMATE AND VEG

  25. Charismatic Mega Fauna • Philippine Eagle • Flying lemur • Tarsier • Philippine Cockatoo • Flying foxes • Bats • Reptiles and amphibians

  26. Landslides in Indonesia

  27. Indonesia

  28. Climate • Tropical climate • Dry season June-September • Wet season December-March • Moderate temperatures • Large range of annual rainfall

  29. Topography • Indonesia has a wide range of topographic features

  30. Vegetation • Tropical plants • Flowering plants • Many trees

  31. Soils • Andosol (Andisols) • Very fertile • Used for horticulture and plantations • Regosols (Inceptisols) • Quartz sand not suitable for dry-land farming • Grumosols • High Ca & clay content • Used for crops in lowlands

  32. Latosol • Tropical rainforests • Lateritic • Tropical • High Al & Fe oxides • Hydromorph (Oxisols) • Alluvial • Podsol • Highly leached • Coniferous forests

  33. What is a landslide? • Material moving down a slope due to gravity • Many possible triggers • Look like an avalanche • 3 types • Slump • Flow • Lahar

  34. Indonesia Mt. Semeru

  35. Conclusion • The soils of New Zealand’s Central North Island is mostly volcanic in origin • Farmer’s crop yields are limited by the acidity of the sub soils in SE/SW Australia

  36. Conclusion • Subsoils are as important as topsoil in tropical Ultisols • Tropical and volcanic soils in combination with precipitation leads to more frequently occurring landslides

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