1. Soil and Soil Profiles

2. Warm up Take out your homework
Title your table of contents and corresponding page soil profiles
Copy the objective from the board
Go to our website and investigate the two links

3. What is Soil
Soil is a mixture of weathered rock particles and other materials
Soil is made up 4 materials
Weathered rock particles (main ingredient)
organic matter 5 % - Decayed organic material is called Humus
water %
air %
Soils differ depending on what types of rock the rock particles come from (granite vs limestone etc)

4. Bill Nye
2 minutes

5. What makes soil different
kind of rocks in the area
climate / weather patterns
Landforms (mountains ; valleys etc)
vegetation
animals and other organisms
time

6. Soil Horizons

7. O horizon
This is the top layer of soil that is made up of living and decomposed materials like leaves, plants, and bugs. This layer is very thin and is usually pretty dark. - It is also referred to as “litter” and contains Humus

8. A horizon
This is the layer that we call "topsoil" and it is located just below the O Horizon. This layer 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.

9. B Horizon
This is the layer that we call "subsoil" and it is located just below the A Horizon. This layer has clay and mineral deposits and less organic materials than the layers above it. This layer is also lighter in color than the layers above it.

10. C Horizon
This is the layer that we call "regolith" and it is located just below the B Horizon. This layer is made up of slightly unbroken rock and only a little bit of organic material is found here. Plant roots are not found in this layer.

11. R Horizon
A mass of rock such as granite, basalt, quartzite, limestone or sandstone that forms the parent material for some soils – if the bedrock is close enough to the surface to weather. This is not soil and is located under the C horizon.

12. Three main soil ingredients
Clay
Sand
Silt
Loam - a mixture of sand, clay and humus
Humus - decaying plants and animals and living organisms

13. Properties of Soil
Texture - This is determined by the size of weathered rock particles it contains
These are classified into three types sand, silt and clay.
Sand particles are the largest and clay are the smallest

14. Properties of Soil Pore space - the amount of space between particles
These spaces are caused by water and air. Soils range from % pore space

15. Properties of soil
Chemistry - This is the nutrients that come from minerals in the soil
Farmers can change the chemistry of the soil by adding lime to reduce acidity.

16. Properties of Soil
Color - Most color comes from iron compounds and humus.
High Iron = red
High humus = black

17. Homework
soil - who needs it New Mexico State 14.23
soil - 4 mnutes