1. Soil as a System A.S: Topic 7: A – D
Topic 7: Lithosphere
Soil as a System
A.S: Topic 7: A – D

2. Lithosphere - Litho = Stone/Rock
- The thin crust between the mantle and the atmosphere.
- Made up mostly of oxygen(47%), silicon(28%), aluminum(8%) and iron(5%).
- Only the top 1% of the lithosphere interacts with the biosphere and is influenced by the atmosphere and hydrosphere = soil (a very thin bridge between the biosphere and the lithosphere)

3. Soil: Abiotic & Biotic Aspects
- Abiotic Factors: a mixture of rock, mineral particles, inorganic nutrients, water, and air in the spaces between the soil particles.
- Biotic Aspects:
- Plants and animals help to make new soil
They defecate, die, and decompose, adding organic matter.
Organic matter helps deliver the right amount of moisture and nutrients to plants.
- Plants roots hold soil together, which reduces erosion.
- Bacteria and Fungi aid in decomposition and weathering, therefore they aid in the formation of soil.
- Soil is their habitat.

4. Soil as a System What kind of system is soil?
Inputs –weathering of parent material, precipitation, infiltration of water, heat, acid deposition, decomposition, organism movement, and nutrients (cycles).
Outputs –leaching, uptake by plants, erosion, nutrients (cycles), evaporation, heat, percolation of water, and organism movement.
Storage – = heat (affecting atmospheric temperature), nutrients, biotic organisms
Inputs = weathering of parent material, precipitation, infiltration of water, heat, acid deposition, decomposition, organism movement, and nutrients (cycles).
Outputs = leaching, uptake by plants, erosion, nutrients (cycles), evaporation, heat, percolation of water, and organism movement.
Storage = heat (affecting atmospheric temperature), nutrients, biotic organisms

5. Soil Profile (See Soil Profile handout)
- Layers of soil are called Horizons
- Humus =decomposing organic material; dark brown or black in color

6. Soil as a Resource - Why is soil considered a resource?
- Soil is considered a non-renewable resource. Why?

7. How does Soil Structure Affect Primary Productivity?
What is Primary Productivity again?
See table handout.
Primary production is responsible for most of the life on Earth. This is the process by which plants convert the carbon dioxide that they have absorbed from the atmosphere and ocean into various other chemical substances. These chemical substances then provide the structure from which an ecosystem can emerge as animals of various kinds consume plant nutrients and develop a food chain. The factors affecting primary productivity are as complex as natural ecosystems are.

8. Composition of Loam Soil

9. Measuring Soil Texture
- Soil Texture = the relative make up of the soil in regards to particle size:
Percentages of sand, silt, and clay
- Method for measuring soil texture:
Begin by drying the soil out.
Then pass it through a series of sieves with decreasing mesh sizes.
This will separate the soil by size.
Use a Soil Texture Triangle diagram to determine the type of soil you have.

12. Measuring the Slope - The steepness of an area.
Why would this be an important factor to measure for soil?
- Can be measured by measuring the rise (height) and the run (length).
Use a tape measure and a field level.

14. Measuring Soil Moisture
- How could you measure how much moisture is in a sample of soil?