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Page 1: SOILS Most important result of weathering and Erosion is soil Soils - soil science = PEDOLOGY Residual soil - soil made from local bedrock (weathered material)

SOILS• Most important result of weathering and Erosion is soil

• Soils - soil science = PEDOLOGY

• Residual soil - soil made from local bedrock (weathered material)

• Transport soil - soil that was moved by wind, water, ice, or gravity (weathered and eroded material)

Page 2: SOILS Most important result of weathering and Erosion is soil Soils - soil science = PEDOLOGY Residual soil - soil made from local bedrock (weathered material)

SOIL • Factors determining soil makeup

1. Climate - Rainfall amount and temperature (most important)

2. Parent Rock - Type and chemical composition

3. Vegetation - Roots and Leaves

4. Topography - hilliness, etc.

5. Time - how long to develop

Page 3: SOILS Most important result of weathering and Erosion is soil Soils - soil science = PEDOLOGY Residual soil - soil made from local bedrock (weathered material)

MATURE VS. IMMATURE SOIL

Mature soil is soil that is fully developed! Has a distinguished A,B, and C horizon.Forest soil, Grassland soil, and Tropical Soil

Immature soil is soil that is not fully developed! Does not have a distinguished A,B and C horizon. Ex. Desert soil, Arctic soil

Page 4: SOILS Most important result of weathering and Erosion is soil Soils - soil science = PEDOLOGY Residual soil - soil made from local bedrock (weathered material)

PEDALFERS VS. PEDOCALS• Pedalfers - Found in eastern half of U.S. where rainfall exceeds 25 inches/year

a. Ped - soil / Al - aluminum / Fe - ferrum - iron al from clay , fe from iron oxide

2. Pedocals -

Page 5: SOILS Most important result of weathering and Erosion is soil Soils - soil science = PEDOLOGY Residual soil - soil made from local bedrock (weathered material)

SOILS PROFILE

• Soil Profile - a cross reaction of soil down to the bedrock. Almost all soils show a “profile” of 3 distinct layers or zones (A,B,C)

A. “A (horizon)” topsoil, gray or black, has humus

B. “B (horizon)” subsoil, more clay is washed down

C. “C (horizon)” Rock fragments and slightly weathered bedrock

Note: More detailed description in your packet.

Page 6: SOILS Most important result of weathering and Erosion is soil Soils - soil science = PEDOLOGY Residual soil - soil made from local bedrock (weathered material)

SOIL TYPES AND CLIMATE• Soil types and climate

1.Most important factor affecting soil is the climate

A. Tropical soil - Warm and wet, speed up chemical weathering. Thus soil forms more quickly. Infertile due to leaching because of rain (high temp. and heavy rainfall). Note: 3 meters

B. Grassland soil - enough rain for grass but not trees. Thick A horizon and very fertile. Note: 1 meter

C. Forest soil - Humid regions with cool season. Well developed horizons. Less than 1 meter. Not very fertile.

D. Arctic soils - High elevation and latitude. Very few layers, shallow. Permafrost.

Page 7: SOILS Most important result of weathering and Erosion is soil Soils - soil science = PEDOLOGY Residual soil - soil made from local bedrock (weathered material)

SOIL CONSERVATIONB. SOIL CONSERVATION

1. Soil Erosion - movement of topsoil by water and wind 4 bill tons (water), 1 bill tons (wind) = loss of topsoil

REDUCE IT!!!!

1. Windbreaks (level plains)

2. Contour farming (plant parallel to land contours

3. Terraces (flattened slopes)

4. Strip cropping

5. No till

Page 8: SOILS Most important result of weathering and Erosion is soil Soils - soil science = PEDOLOGY Residual soil - soil made from local bedrock (weathered material)

RATES OF SOIL FORMATION

• Factors of Rates of Soil Formaiton

1. The rocks themselves - Igneous and metamorphic most resistant, sedimentary least resistant because of pores.

2. Surface Area

3. Climate - Warm and wet = chemical weathering

Cold and Dry = mechanical weathering

4. Topography

5. Biological Factors


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