Soil Notes:


1. profile- vertical slice through rock, sediment, or 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. soil profile-the horizons of a soil

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

8. leaching-removal of minerals that have been dissolved in water, is chemical weathering that moves nutrients to lower levels of soil.  It helps enrich the lower horizons.

9. Factors affecting soil formation:

    a. climate

    b. length of time that rock has been weathering

    c. slope of the land

    d. type of rock

    e. type of vegetation


10. Composition of soil-rock, mineral fragments, organic matter, air and water.

11. organic matter slowly changes to humus.

12. soil profiles have layers called horizons. 

13. The top of the soil may be covered with litter, sometimes called the O horizon. 

14. The actual top layer of soil is called the A horizon.  The A horizon is also known as topsoil.  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.


15. The B horizon is known as the 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. 

is less fertile because contains less humus.


16. The C horizon 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. 

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

18. climate and other factors determine the type of soil that develops.

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

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

21. Soil structure describes the arrangement of particles in a soil