Chapter 15 The Geography of Soils Flashcards
1
Q
Soil
A
Natural surface layer of Earth
- Composed of mineral and organic matter (50%)
- Composed of air and water stored in pore space between soil particles (50%)
- Essential to life on Earth and society
- Plant growth/Habitat for animals and organisms
2
Q
What factors form soil?
A
- Parent material (rocks)
- Climate
- Biological Activity
- Relief and Topography
- Time
3
Q
Soil Forming Factors:
Parent Material
A
Weathered bedrock, rock fragments,and sediment determine soil types
4
Q
Soil Forming Factors:
Climate
A
- Soils are influenced by temperature and precipitation
- Determine chemical reactions, organic activity, movement of water within soils
5
Q
Soil Forming Factors:
Biological Activity
A
- Vegetative cover dies, decomposes, and
incorporates into soil - Burrowing insects and animals rearrange soils; incorporated after they die
- Microorganisms contribute
- Humus
- Decomposed organic matter; a vital component of soil
6
Q
Soil Forming Factors:
Relief and Topography
A
- Influences the type of soil and its thickness
- Steep slopes; less soil
- Flat land; more soil
7
Q
Soil Forming Factors:
Time
A
- Soils take thousands of years to develop
- Soils develop more quickly from sediment than bedrock
- Soils develop faster in warmer, humid climates
8
Q
Soil Profile
A
Vertical section of soil layers
9
Q
Soil Horizon
A
Individual layer of soil within a profile
10
Q
Horizons
A
O, A, E, B, C, R
11
Q
Soil Profile and Horizons:
O Horizon
A
- Top of soil profile
- Organic material
- Nutrient rich
12
Q
Soil Profile and Horizons:
A Horizon
A
- Top soil; where plowing and pasturing occurs
- Dark colored
- Nutrient rich
13
Q
Soil Profile and Horizons:
E Horizon
A
- Leached layer
- Clays, oxides, and organic matter are washed downward by water
- Light colored
14
Q
Soil Profile and Horizons:
B Horizon
A
- Accumulation layer of clays,
aluminum, iron
15
Q
Soil Profile and Horizons:
C Horizon
A
- Weathered parent material; regolith
- Plant roots and soil microorganisms
rare
