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

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

The Formation of Raw Volcanic Soil in New

Zealand

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.

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

Climate and Topography

• Climate: Cold and high rainfalls.

• Topography: Raw volcanic soil forms in the vicinity of the source volcano

Biota• Organisms: Most soil animals and

micro-organisms are concentrated in the topsoil.

• Plant Life: Vegetation rapidly recovers on volcanic soils.

Profile Characteristics• A horizon: is dark

in color• B horizon:10-

15cm thick• C horizon: is pale

yellow-brown

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

Acidic Soils of Australia

Tyler Huntley

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

Agricultural

• Increase in acidification

• Soil nutrient uptake

Construction

• corrode metal pipes and dissolve concrete.

• foundations of buildings

Surface Water

• Run-off• Consequences

Prevention

• Identifying them

• Liming

• Loss of crop production

Lowland Dipterocarp forests

Soil associations

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

Types of Soils

• Ultisols – most common in SE Asia• Inceptisols

– Very steep slopes

• Oxisols• Characterized by

– Morphology– Physiochemical properties– Clay mineralogy

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

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

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

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

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

Charismatic Mega Fauna

• Philippine Eagle• Flying lemur• Tarsier• Philippine Cockatoo• Flying foxes• Bats• Reptiles and

amphibians

Landslides in Indonesia

Indonesia

Climate

• Tropical climate

• Dry season June-September

• Wet season December-March

• Moderate temperatures

• Large range of annual rainfall

Topography

• Indonesia has a wide range of topographic features

Vegetation

• Tropical plants

• Flowering plants

• Many trees

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

• Latosol– Tropical rainforests

• Lateritic– Tropical– High Al & Fe oxides

• Hydromorph (Oxisols)

• Alluvial

• Podsol– Highly leached– Coniferous forests

What is a landslide?

• Material moving down a slope due to gravity

• Many possible triggers

• Look like an avalanche

• 3 types– Slump– Flow– Lahar

IndonesiaMt. Semeru

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

Conclusion

• Subsoils are as important as topsoil in

tropical Ultisols

• Tropical and volcanic soils in combination

with precipitation leads to more frequently

occurring landslides