Soil Notes:  

1. profile- vertical slice of soil

2. soil-mixture of weathered rock, decayed organic matter, mineral fragments, water and air, soils are made from weathered rock fragments.

3. organic matter is anything that used to be alive, plants, animals, and such.

4. humus-dark colored material that forms when organic matter partly decays, the very small particles of decayed plant and animal material found in soil.

5. horizon-layer of soil

6. litter-leaves, twigs, and other surface organic material

7. leaching-water moves nutrients to lower levels of soil.  It helps enrich the lower horizons.

8. there are many different types of soil in the U.S.

9. Factors or things that affect soil formation:

    a. climate

    b. length of time that rock has been weathering

    c. slope of the land (hilly or flat)

    d. type of rock

    e. type of vegetation  

10. soil profiles have layers called horizons. 

11. O horizon-the top of the soil may be covered with litter, sometimes called the O horizon. 

12. A horizon or Topsoil-the actual top layer of soil is called the A horizon.  Topsoil always contains more humus and fewer rock and mineral particles than the other layers of soil.  Is dark in color because of the humus.  

13. B horizon or subsoil and is found beneath the A horizon.  It will be lighter in color and contains less humus.  The B horizon contains some nutrients and materials brought down by leaching.  As we know, leaching is the removal of minerals that have been dissolved by water. 

14. The C horizon or parent material is made of partially weathered rock and is the bottom horizon in a soil profile.  It is often the thickest layer and is NOT really part of the soil.  Beneath this layer is bedrock. 

15. topsoil can take hundreds and thousands of years to form.

16. Soil texture describes the amounts of soil particles of different sizes that a soil contains.

17. Soil can be composed of sand, silt, and clay. 

18. Sand is small, coarse-grained pieces of rock. You can see and feel the individual pieces. Sand feels gritty. It does not stick together


19. Silt is very soft and could be described as powdery. The particles of silt are so small that you would only be able to see them with a microscope. Water soaks into silt easily. Silt particles do not stick together.


20. Clay is even finer than silt. Clay particles fit closely together. Clay sticks together very well and will form clods. Soil that contains a great deal of clay would be described as heavy. Clay traps water


21. Loam is a soil that is a mix of sand, silt, and humus. Great for growing!