1. Soil Quality
7-4.4 Explain the effects of soil quality on the characteristics of an ecosystem.

2. INTRODUCTION
Soil is one of the most valuable abiotic factors in an ecosystem because everything that lives on land depends directly/indirectly on soil.
Soil effects types of plants that can grow in an ecosystem  which directly impacts the types of other organisms that can live there.
If the soil quality changes in any of its properties, the ecosystem will also change.

3. SOIL QUALITY Based on qualitative properties that can be observed
Such as:
soil profile
composition
texture
particle size

4. SOIL PROFILE Each layer is called a horizon Bedrock Parent Material
Label the horizons
Organic Layer
Each layer is called a horizon
Label the Horizons from the Word Bank below…
Bedrock
Parent Material
Subsoil
Topsoil
Horizon A aka
Horizon B aka
Horizon C aka
Horizon D aka

5. SOIL PROFILE
Top Soil
Nutrient rich layer most suitable for the growth of plants
Contains a mixture of:
clay
humus (decayed organic material)
minerals

6. SOIL PROFILE Subsoil Area where groundwater can collect and flow
Lighter in color because mostly made up of minerals such as sand, pebbles, clay or silt
Minerals from the topsoil layer gradually make their way down into the subsoil
because they are heavier than decomposing organic matter higher up the soil profile.
The thickness of subsoil layers varies widely but it's usually deep enough to cover the root systems of large shrubs and trees.

7. SOIL PROFILE Parent Material Bedrock
formed of small rocks and large stones or pebbles.
usually free of plant and tree root systems
Bedrock
solid rock that is gradually weathered and broken up to produce the mineral content of the soil layers sitting above it
depth of the bedrock varies by location, and in some areas the bedrock is exposed above ground level
Bedrock is usually found between 5 feet and hundreds of feet below the topsoil horizon.

8. Litter (dead stuff on top) decomposes into more humus
Litter  Humus

10. SOIL COMPOSITION Composition = Mixture of: what makes up the soil air
water
rock particles/minerals
humus:
decayed organic material
makes soil more fertile
organic- anything that is or was alive
“OM”= Humus, Decayed organic material
What does the zig-zag between air and water mean?

11. SOIL COMPOSITION silt clay sand What does weathered mean?
Broken down by wind, rain, ice, gravity, heat, pressure, chemicals
Weathered bedrock material provides what three things in soil?
sand
silt
clay
The combination of these materials in soil determine the soil type and affects the type of plants and animals that can grow/live in it.

12. Other things that can affect soil components include:
SOIL COMPOSITION
Other things that can affect soil components include:
type of plants
climate
time
slope of the land

13. SOIL TEXTURE Texture depends on the SIZE and PROPORTION of particles.
Texture names are based on the % of:
SAND, SILT, CLAY
Texture names include:
LOAM
*garden, little sand
SANDY CLAY LOAM
SILT LOAM
CLAY
SAND
Soil texture affects the amount of WATER absorbed
Which affects use by plants and animals

15. As water empties from a mountain stream, its velocity starts to decrease. The largest size particles, like sand, are the first to drop out of suspension (Site A). Fine, clay size particles can be carried further away from the base of the slope before they are deposited. As a result, coarse textured soils tend to be found near the base of the mountain and fine textured soils are located further away (Site C).

16. SOIL PARTICLE SIZE Particles- soil “parts”
clay
silt
fine sand
course sand
2 mm gravel/pebbles
SOIL PARTICLE SIZE
Particles- soil “parts”
Effects how fast water can move through or be absorbed and used
Aka soil permeability

17. Soil Components Separated
If this soil sample is 50% sand, 30% silt, and 20% clay, what soil texture is it?
Use the Soil Textural Triangle.
____________________________________

18. Soil Quality is based on:
Permeability pH

19. Permeability & Porosity
Permeable
How freely water flows in soil
Calculate the rate of drainage
Porosity
Open air spaces (PORES) in soil
The higher the porosity, the less or more permeable?

21. Soil Descriptions

23. pH good soil pH is between 4 and 10 Plants enjoy pH 5 to 7
Regardless of the nutrients present in the soil, if the pH is not suitable those nutrients will be inaccessible to the organisms
LIME can be a fertilizer that can alter pH to make the nutrients more accessible
added to make more basic
(brings pH up or down?)

25. Farmer Tackett took a pH soil sample in 9 evenly spaced plots as shown below. Place a smiley face in Soil Plots where you predict plants would best grow, and a frown face in Soil Plots where you think plants would grow the least. 6 8 9 5 7 3

27. According to the soil profile, in which layer are most of the soil’s nutrients most likely found? ____
What layer is called parent material? ____
What layer is called bedrock? ____
What layer is called subsoil? ____

28. A B C D Which rock type is the:
1. most permeable (rapid flow of water passing through)? _____
2. least permeable (slowest flow of water passing through)? ___
3. moderately permeable? ______

29. 1. Which of these things is a primary ingredient of humus?
A) Dead plant material
B) Minerals
C) Metals
D) Rocks from earth’s crust
2. What effect do plants’ roots have on rock?
They break it apart
They cause to to undergo chemical change
They hold it together
They weather it
3. Why is topsoil darker than other levels of soil?
It contains all the darker-colored minerals
It contains bits of burned trees
It contains more organic matter
It contains volcanic rock