1. Soil .

2. What is soil? 
Soil is the loose material on Earth’s surface where plants can grow

3. Why should you care about soil?
One of Earth’s most valuable natural resources
Everything that lives on land, including humans, depends directly or indirectly on soil

4. What is Soil Fertility?
A measure of how well plants should grow in the soil
A measure of how nutrient-rich the soil is
The more humus there is in the soil, the more fertile it is!

5. Value of Soil
Fertile soil is valuable because there is a limited supply and takes a long time to form
Soil value goes down when it loses its fertility and/or when topsoil is lost due to erosion
Fertility loss – from exhaustion - George Washington Carver developed new crops and farming methods to help restore soil fertility to South (peanuts =legumes-add nitrogen that plants need)

6. Con’t Loss of topsoil – water and wind erode exposed topsoil
Plant cover helps protect it
Dust Bowl – end of 1800’s , years of droughts, almost all Great Plains turned into farms or ranches, wind storms blew topsoil creating giant dust storms

7. What is it made of (what is its composition?)
Soil is a mix of rock particles (weathered bedrock), minerals, decayed organic material, water and air
Weathered bedrock = sand, silt and clay
Humus = decayed organic material
Dark colored material plants need
Contains nutrients

8. How Does Soil Form?
Forms as rock is broken down by weathering & mixes with other materials on surface.
Constantly being formed where ever bedrock is exposed

9. What is a soil profile?
A soil profile refers to the layers of the soil
These are known as Horizons O, A, B, C and R

10. The O horizon is made of decaying plant and animal remains
The O horizon is made of decaying plant and animal remains. It stands for organic matter.
Bedrock is under the C Horizon. It is called the R Horizon.
Textbook pg. 120

11. Litter It’s on top of the first layer of soil—the O horizon
Contains grass, plants, and animals

12. Horizon A; Topsoil 1st layer of soil
Darkest layer of soil (dark brown or black)
Contains humus, plant roots, small animals, water, and nutrients for plant growth
The darker the soil, the more nutrients it contains

13. Horizon B; Subsoil 2nd layer of soil Lighter in color (reddish brown)
Fewer nutrients and water
Limited plant growth

14. Horizon C; Parent Material
3rd layer of soil
Lightest in color (gray)
No nutrients, animals, or plant growth
Contains weathered rock and sediment

15. In the order they form 1st = Horizon C 2nd = Horizon A 3rd =Horizon B
It forms as bedrock weathers and rock breaks into small particles
2nd = Horizon A
Forms as plants add organic material to the soil and plant roots weather pieces of rock
3rd =Horizon B
Forms as rainwater washes clay and minerals from the A horizon to the B horizon

16. How is Humus Formed? Decomposition
Organisms that live in soil (decomposers) break down dead plant remains, dead plant roots, other dead organisms into humus
Decomposers = fungi, bacteria, worms & other organisms

17. What is Soil Texture & Why is it Important?
Describes the feel of the soil and the size of the soil particles
Smallest particles to largest =
Clay – Silt – Sand – Gravel (pg. 119)
Important for plant growth
Clay holds lots of water so plants could drown
Sand lets water pass through quickly so plants could die of thirst
Loam (=parts clay, sand & silt) is best for most plants

18. The soil must be mixed & aerated
Earthworms dig down and mix humus with the other parts of the soil
Burrowing mammals (mice, moles, prairie dogs, gophers, etc.) also dig and break up hard, packed soil and mix in humus
(pgs )

19. pH A measure of how acidic or alkaline (basic) a material is 7=neutral
0-7 = more acidic (lower number = more acidic)
7-14 = more basic (higher number = more basic)
Different plants need different pH levels
If too acidic then add lime
If too basic then add sulfur

20. Moisture
Loam is about 25% water, and is the best soil for growing most types of plants

21. What does the color of soil tell us?
Generally, the darker the soil, the more nutrients it has. Darker soil usually means it has more humus in it.

22. So what is soil conservation and stewardship
Stewardship = to take good care of something.
Soil stewardship reminds us of our responsibility to care for our soil resources
Soil conservation = management of soil to prevent its destruction

23. Humans can affect the quality of the soil
Soil quality can affect human health
Humans are responsible for monitoring and maintaining soil quality
Avoiding pollution
Chemicals
Animal and human waste
Soil Conservation

24. 3 Methods of Soil Conservation
Contour Plowing
Farmers plow fields along curves of slope to help slow runoff of extra rainfall
Prevents extra rainfall from washing soil away

25. Conservation Plowing (Low-Till or No-Till Plowing)
Farmers leave dead weeds and stalks in ground
Try to disturb soil and plant cover as little as possible

26. Crop Rotation
Farmer plants different crops in a field each year so same nutrients are used up every year
After planting crops that use a lot of a certain nutrient, plants crops that put back that nutrient the next year

27. Terraces
Flat, step-like areas built on a hillside to prevent rainwater from running downhill

28. Wind Breaks
Rows of trees between fields to “break” or reduce the force of winds.

29. Cover Crops or Vegetative Cover
Planting crops all year long so fields are never left bare and the plants hold the soil in place.

30. Responsible Land Use Things that increase soil erosion:
Logging, mining and construction
Animal grazing
Growing crops
Recreation
Off road vehicles