1. Let's dig up our
knowledge on
soil

2. Soil Soil is one of the most important of Earth’s resources.
It is sometimes called the “outer skin” of the Earth, like the skin of a fruit.
This layer provides a soft cushion covering much of the hard rock surfaces of the planet. (Do Apple Demonstration)

3. The Earth’s System Oceans Lakes Rivers Soil too rocky Soil too wet
Arctic, Antarctic, deserts, swamps, & mountains
Rivers
Soil too rocky
Soil too wet
Soil too hot
Soil for growing
Developed by man

4. Post Apple Demonstration Questions
Based on what you have seen, why do you think soil is an important natural resource?
Soil is necessary for plants to grow because it hold nutrients they need and gives them support.
Soil is also needed to grow food for animals, including humans.
There is a limited amount of soil. If the soil was covered by buildings and roads there would be no place to grow food or for animals to graze.

5. Applying what you have learned…
Post Apple Demonstration Questions
Applying what you have learned…
What role does soil play in helping to maintain life on Earth?
Soil is essential to plants because it holds nutrients they need and provides then with support.
Soil is also necessary to grow food for animals, including humans.

6. What is Soil?
You know what soil looks like…but where does it come from?
Weathering breaks down rocks, then
particles of rock mix with decaying plants and animals and their waste products to form soil.
Soil is a mixture of many materials, including sand, silt, clay, water, fungi, bacteria, and decayed plant and animal material (humus).

7. What is Soil?
All soil is comprised of solids (rock and mineral and organic matter), liquid (water), and gas (air).
Plants need all 3 forms of matter to survive.
Plants get their nutrients from the materials and minerals that have dissolved in the water. The water is then stored in in some of the air spaces.
Air is necessary in soil so that the roots have room to grow.

8. Sand, Silt & Clay Sand is any small stone particle in the soil.
Silt feels smooth and powdery.
Clay is the smallest type of particle found in soil.
If a particle of sand
were the size of a basketball,
and clay would be
the size of a golf ball.
then silt would be the size of a baseball,

9. Types of Soil
There are many different types of soils, based on the unique mix of ingredients each contains.
Each type of soil has its own:
color
texture
Ability to hold water
Ability to support life
The make-up of a particular soil influences the types of plants and animals that can live in it.

10. Four Main Properties of Soil
Soil Color
Can range from light yellow or red to dark brown or black.
The types of rock particles found in the soil greatly affect its color.

11. Four Main Properties of Soil
Soil Texture
Texture is how something feels.
Grainy
Slippery
Fine
Course
Smooth
Soil texture is based on how large the pieces of clay and other particles in the soil are, and how much decayed material there is.

12. Four Main Properties of Soil
Stores Water
Soil is able to hold (retain) water because of its clay and dead plant and animal matter
These materials take in absorb water
Soils with larger amounts of clay and decayed material hold more water than sandy soils do.

13. Four Main Properties of Soil
Supports Life
Soils contain different chemicals, like salts and nutrients
These chemicals come from rock particles or from decayed plants and animals
A soil’s chemicals and ability to absorb water affect its ability to support life.

14. A Profile of Soil
The type of soil differs from place to place, even in different parts of your own backyard.
This is one reason why different areas grow different plants.
Even in a single place, the soil is made up of several layers.

15. Layers Topsoil The top layer of soil. Only a few centimeters thick.
Topsoil contains rotting plant and animal materials called Humus.
Topsoil also contains bits of weathered rock.
Tree roots break up rocks in this layer.
Earthworms, insects, and snails live in this layer because it is close to the air and contains nutrients.
Lower layers contains more sand and rock.

16. Subsoil The second layer of soil. It is mostly made up of small rocks.
Subsoil forms as larger rocks are broken up.
Since the subsoil is near the surface, temperature changes help weather the rocks in this layer.
It is the layer where the most weathering of rocks happens.
Tree roots also break up rocks in this layer.

17. Bedrock This is the bottom most layer.
It is mostly made of solid rock.
Rocks slowly widen and break up the top part of the bedrock.
Bits of rock break off.
Over time, these rock bits become part of the upper layers of soil.
How layers of soil form

18. Conserving the Soil Soil is a very important resource.
A resource is a source or supply from which benefit is produced.
To preserve the soil against erosion, farmers practice soil conservation.
Soil conservation is doing things to prevent soil from being eroded.
Farmers plant crops to hold the soil together against the wind or heavy rains.
Farmers also plow across hills and slopes instead of up and down to reduce soil erosion from running water.

19. Conserving the Soil Supports Life
Soils contain different chemicals, like salts and nutrients
These chemicals come from rock particles or from decayed plants and animals
A soil’s chemicals and ability to absorb water affect its ability to support life.
Are you a Soil Genus?

21. Cool Soil Websites Erosion Weathering Pictures
Weathering Pictures

22. Notes on Soil What is soil?
Soil provides a soft cushion that covers much of the Earth’s hard rock.
Without soil, the Earth’s land surface would be barren rock and sand, which could not support many forms of life.
Soil is essential to plants since it stores the nutrients they need and provides then with support.
Soil is a mixture of several different types of materials, including crushed rock particles and decayed materials.

23. Properties of Soil Notes.
Properties of Soil
There are many different types of soils, based on their unique mix of ingredients
Color- Soil can vary from yellow or red to dark brown or almost black
Texture- Soil texture is based on its ingredients, such as sand, clay, and humus.
Stores Water- Soil can hold varying amounts of water, depending on how much clay and decaying material it has.
Supports Life- Soil Contains different chemicals that allow it to support plant life.