GS - Global Soils

Question 1

Define:

Parent Material?

Answer 1

The source of the rock fragments that make up soil

Question 2

Define:

Organic Matter?

Inorganic Matter?

Answer 2

Everything but inorganic matter

Minerals, Sediment, Clay, Sand, Silt

Question 3

Define:

Silt?

And Sand? Sizes?

Answer 3

Slightly smaller than sand;
Made up of Quarts, Feltzspars, & Micha’s

Sand: 2.000-.005 mm ; Silt: 0.05 -.002 mm

Question 4

Define:

Clay?

Size?

Answer 4

Tiny collodial particles (more round than the flatter silt and sand)
Clay combines with water

Less than .002 mm

Question 5

Define:

Soil?

Avg Depth of Soil?

Answer 5

The thin surface layer made up of a mixture of weathered mineral particles, decaying organic matter, living organisms, gases, and liquid solutions

6 in.

Question 6

Define:

Regolith?

Nickname?

Answer 6

A layer of loose inorganic material and the principal product of weathering

‘Blanket Rock’

Question 7

Identify:

Makeup of Soil?

Answer 7

45% Minerals
25% Water
25% Air
5% Organic Matter

Question 8

Identify:

What are the 5 soil-forming factors?

Answer 8

1. Geologic
2. Climactic
3. Topographic
4. Biological
5. Time

Question 9

Explain:

Geologic Factor?

Answer 9

• Parent Material
• Chemical composition & physical characteristics -> Soil texture & texture
• Young soils reflect parent rocks
• Influence of parent material diminishes over TIME

Question 10

Explain:

Climactic Factor?

Why is it the MOST important?

Temperature & Precipitation relationships

Answer 10

• Temperature & Moisture
• DEEPEST soil in warm, humid areas
• SHALLOWEST in cold, dry areas
• Water introduces tiny particles and chemicals
• CLIMATE most IMPORTANT

WATER is the primary agent for soil development

H Temperature & Precipitation = Rapid Formation
L Temperature & Precipitation = Slow Formation

Question 11

Explain:

Topographic Factor?

Answer 11

• Thick soil in flat areas
• Thin soil on slopes

Question 12

Explain:

Biological Factor?

Most influential elemnt?

Answer 12

• Roots provide passageways for aeration and drainage
• Animals: compaction, waste, tunnels & burrows
• Microorganisms: Decompose organic matter

Bacteria in microorganisms

Question 13

Explain:

Time Factor?

Answer 13

• Slow development (Geologic time)
• Degradation can befast
• Erosion (Exposed Topsoil)
• Depletion of Nutrients

Question 14

Explain:

Histosols?

Developmental Pathway Factor? Where?

Answer 14

• Wet, Swampy, Waterlogged Areas
• Soil is:
  - Black
  - Acidic
  - Lacks Oxygen
  MUCK
• ‘LIVING TISSUE

Site-Dominated Pathway; Mid & High Latitudes

Question 15

Explain:

Gelisols?

Developmental Pathway Factor? Where?

Answer 15

• GELATO
• Cold Climates
• Minimum, Large Frozen Layer

Climate-Dominated Pathway; Arctic & Subarctic Regions

Question 16

Explain:

Mollisols?

Developmental Pathway Factor? Where?

Answer 16

- ‘Soft’
- Deep and rich A Horizon
-Enough precipitation to grow the grass but not enough for trees

Climate-Dominated Pathay - Central Asia, Great Plains, Argentina

Question 17

Explain:

Aridisols?

Developmental Pathway Factor? Where?

Answer 17

Dry
- Thin and Sandy
- Lack of Precipitation
- 1/8 of the Earth’s Length area

Climate Dominated - Desert and Semiarid Climates

Question 18

Explain:

Oxisols?

Developmental Pathway Factor? Where?

Answer 18

• Soils rich in oxygen
• High degree of mineral alteration and profile development
• In Tropics

Time Dominated - Warm & Moist Climates, Hawaii, Brazil, Equator Africa

Question 19

Explain:

Andisols

Developmental Pathway Factor? Where?

Answer 19

• ## Volcanic Ash of the Andes

Parent Material - Regions of Japan, Indonesia, Andes, Pacific NW

Question 20

Explain:

Vertisols?

Developmental Pathway Factor? Where?

Answer 20

• Swell and Crack b.c of clay
• CHURNS
• Needs a wet season and a dry season

Parent Material - Tropical Savannas & Subtropical Savannas