soil is the top layer of the earth. the soil layer of the earth is...
TRANSCRIPT
SoilPresentation.notebook
1
March 20, 2014
Oct 711:47 AM
Soil is the top layer of the earth. The soil layer of the earth is approximately
3 meters (10 feet) thick.
Oct 712:31 PM
Soil is composed of rock particles, minerals, decayed or decaying organic material, water, and air.
SoilPresentation.notebook
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March 20, 2014
Oct 712:44 PM
Decayed organic material (once living organisms) such as plants or animals is broken down by decomposers. Decomposers can include bacteria, fungus, insects, and animals.
This decomposed material will be turned into hummus, which can be used by plants and animals to sustain life.
Oct 712:51 PM
Fertile soil is soil that which can support plant growth. Loam is the best soil for growing many plant types. Loam is made up of almost equal parts of clay, sand, and silt.
SoilPresentation.notebook
3
March 20, 2014
Oct 712:55 PM
Different size particles in soil can be identified by their diameter: Clay is less than 1/256 mm Silt is between 1/256 and 1/16 mm Sand is between 1/16 mm and 2 mm Gravel or Pebbles are larger than 2mm
Oct 712:59 PM
If you took a soil profile (cut about 2 meters of the top of the earth) you would find different layers or horizons. These horizons have soil that differs in texture and color.
SoilPresentation.notebook
4
March 20, 2014
Oct 71:04 PM
Horizon O contains living organisms and decaying organic material.
It is a very small percentage of the soil layers and is usually the darkest layer.
Oct 71:07 PM
Horizon A is also called “topsoil”. The topsoil is made up of minerals and decomposed organic matter and it is also very dark in color.
This is the layer that many plants roots grow in.
SoilPresentation.notebook
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March 20, 2014
Oct 71:11 PM
Horizon B is also called “subsoil”. The subsoil is composed of clay and mineral deposits.
It contains less organic materials than the layers above it.
Oct 71:14 PM
Horizon C is also called the "regolith”. This layer is made of slightly unbroken rock.
Only a little organic material is found here. Plant roots are not found in this layer.