Soil

Soil

The following power point was adapted from Ryan P. Murphy. A full collection of his amazing power points can be found

at: http://sciencepowerpoint.com/index.html

SOIL

http://www.youtube.com/watch?v=Uv1btp3E8qk

Weathering is the process that will, overtime, create soil.

Soil is a mixture of weathered rock and decaying organic material.

Soil Formation

•Soil is formed as rock is broken down by weathering and is mixed with other materials on the surface by burrowing animals. •Soil is constantly being formed wherever bedrock is exposed. •Bedrock is the solid layer of rock beneath the soil.

Five Factors That Affect Soil Formation

1. Climate: temperature and rainfall

2. Plants and animals3. Topography: flat lands

are more fertile than hilly lands

4. Parent material 5. Time: more time =

healthier soil

Four Steps To Soil Formation1. Bedrock disintegrates

Four Steps To Soil Formation1. Bedrock disintegrates2. Parent material forms

Four Steps To Soil Formation1. Bedrock disintegrates2. Parent material forms3. Organic matter collects forming humus

Four Steps To Soil Formation1. Bedrock disintegrates2. Parent material forms3. Organic matter collects4. Thick vegetation grows and gives back to the soil

Soil Composition•Soil is a mixture of rock particles, minerals, decayed organic material, air, and water. •The type of rock particles and minerals depends on the bedrock that was weathered and the type of weathering. •Sand, Silt, and clay make up the portion of soil that comes from weathered rock.

Humus•Decayed, organic material in soil•Dark in color•Forms from decaying plant and animal material•Creates spaces in soil for air and water•Rich in nutrients that plants need to grow

Color Of Soil- helps determine what soil is made of and its health

Black Soil• Lots of organic matter (carbon)• May be poorly drained• Usually fertile

Brown Soil• Lots of sand and clay• Well drained• Good soil

Light brown, white, orange, red, yellow

• Many compounds present (iron, manganese, sulfur)

• High is salt• Not as healthy• Iron turn rust color

when it mixes with oxygen (oxidation)

Particles of Soil

• The type of soil depends on its particles• The combinations of particle size can

determine how well plants grow in soil

Soil Texture and Particle Size• Gravel: 2-7.5cm

Soil Texture and Particle Size• Gravel: 2-7.5cm• Sand: 2-.125mm

Soil Texture and Particle Size• Gravel: 2-7.5cm• Sand: 2-.125mm• Silt

Soil Texture and Particle Size• Gravel: 2-7.5cm• Sand: 2-.125mm• Silt• Clay

Soil Horizons•Soil Horizon is a layer of soil that differs in color and texture from the layers above or below it.

• O – organic layer (leaves, pine needles, twigs, decay)

• A – Top Soil: dark color is from the mixing of humus with weathered materials

• E – Eluviated zone; movement of dissolved materials from A horizon

• B – Sub Soil; Illuviated zone – contains soil materials leeched from above

• C – Parent Material; partially weathered mineral particles

• D/R - Bedrock

Rate of Soil Formation

•Depends on climate and type of rock•Weathering occurs most rapidly in a warm, rainy, climate•Some rocks, like limestone, weather faster than other types of rock, like granite.