1. Soil Basics Score Four: Students, Schools, Streams, and the Bay
Sp. Ed, 9-12
Soil Basics
Interstate Commission on the Potomac River Basin – Score Four: Students, Schools, Streams, and The Bay
This PowerPoint is intended for use with ICPRB’s Score Four Lesson 1 of the soil series developed for Special Education, grade 9-12.
Score Four: Students, Schools, Streams, and the Bay
Rebecca Wolf and Nguyen Le
Interstate Commission on the Potomac River Basin
Rebecca Wolf and Nguyen Le
Interstate Commission on the Potomac River Basin

2. Soil: The Foundation For a Plant’s Success
Soil gives plants:
Food (nutrients & minerals)
Water
Oxygen
A place to grow!

3. It’s Not Just Dirt Soil is made of: Tiny particles called minerals.
Spaces between the minerals, known as pores.
Dead plants, animal matter, and worm droppings, called organic matter.
Living organisms, such as worms, insects, bacteria, and fungi.
Students might not know what a fungus is. Examples include mushrooms and toadstools. The part we see above ground is the fruiting body of an extensive system of underground roots.

4. Soil: It’s a Mix of Minerals
Three types of minerals make up soil:
Sand
Silt
Clay
To help students comprehend minerals, teachers can pass around samples of sand, silt, and clay, and soil from the campus that is a mix of sand, silt, and clay. It can help students to comprehend minerals, it they feel and discuss how soils in different area likely have different proportions of each of these minerals in them.

5. Pores – Where the Action Takes Place
Pores are spaces between soil particles.
Pores also are made by roots, insects, and worms.
Pores hold water and oxygen.
Pores provide habitat homes for organisms.
soil
Root
Pores filled with water and air
Pore spaces also exist between lumps of soil, called aggregates, and in bedrock. This presentation focuses on particles to introduce the concept.

6. Organisms Live in Healthy Soil
Microscopic organisms we can’t see with our eyes
Bacteria
Nematodes
Fungus
Some organisms we can see:
Additional Information:
Things we can’t see (microorganisms)
Bacteria, Algae, Fungus, Protozoa, Nematodes, and Arthropods – organisms with jointed legs, including insects, crustaceans, such as sow bugs (pill bugs), spiders.
10-25,000 arthropods in a square foot of forest soil. A billion bacteria in a teaspoon of healthy soil.
Things we can see:
Worms, insects, animals
A variety (diversity) of organisms in soil is necessary for healthy soil, as they are part of the food web and ecosystem. Competition among these species keeps harmful organisms under control.
The more species and more organisms, the better the soil is for plants AND clean water.
Worms
Springtails

7. Part 2: Soil Texture

8. More about Sand, Silt, and Clay Minerals
A grain of sand is rounded and big enough to see.
Silt is flat and can be seen with a microscope.
Clay is flat. It is so tiny, a special microscope is needed to see it.
If SAND were as big as a beach ball,
SILT would be the size of a frisbee,
And CLAY would be the size of a dime.
Teachers can bring in items to show relative size and shape of minerals. If sand particles were the size of a basketball, clay particles would be the size of a period at the end of a sentence.
A million grains of clay will fit in the space occupied by one average grain of sand.
Electron microscope image of clay (source: Well-sorted clay particles are sometimes compared to a deck of cards or stack of newspapers to help people understand their structure.

9. The feel of soil gives clues to what is in it.
The minerals in soil affect how it feels to the touch.
Some soils are mostly sand; some have lots of clay. Each feels different to the touch.
Have you noticed this?
The feel of a soil is called soil texture.
Photos:

10. Soil Texture Lab You will observe how different minerals feel.
You will use this information to guess what minerals are in your school soil.
How do you expect sand to feel like?
Why?
Sand is gritty. Sand feels different depending on where it is and how coarse (large) it is. Note that grains of sand are not all the same size. Think about the different types of sand on beaches. Sandy Point State Park feels coarse. The sand at Ocean City or on the Atlantic Oceans in Florida feels finer or softer. Why?

11. Definitions for teachers
Source (unless otherwise noted): Soil Health and Glossary, National Resources Conservation Service
Bacteria: Microscopic, single-celled organisms. They include the photosynthetic cyanobacteria (formerly called blue-green algae), and actinomycetes (filamentous bacteria that give healthy soil its characteristic smell).
Fungi: Multi-celled, non-photosynthetic organisms that are neither plants nor animals. Fungal cells form long chains called hyphae and may form fruiting bodies such as mold or mushrooms to disperse spores. Some fungi such as yeast are single-celled.
Mineral: A mineral is an element or chemical compound that is normally crystalline and that has been formed as a result of geological processes" (Source: Nickel, E. H., 1995). "Minerals are naturally-occurring inorganic substances with a definite and predictable chemical composition and physical properties." (Source: O' Donoghue,1990).
Organic matter: any material that is part of or originated from living organisms. Includes soil organic matter, plant residue, mulch, compost, and other materials
Silt: a granular material of a size between sand and clay, whose mineral origin is quartz and feldspar. Silt may occur as a soil (often mixed with sand or clay) or as sediment mixed in suspension with water (also known as a suspended load) in a body of water such as a river. (source: Wikipedia)

12. Resources for Teachers
Flow diagram for Texture by Feel. Commonly used in the field. Provided by the USDA Natural Conservation Resources Service. (Click here for a high-resolution version of the graphic.)
Soil Science Society of America provides an excellent bank of soils lessons for multiple grades covering texture, biology, chemistry, forensics, and more.
Basic Hydrologic Science Course Runoff Processes Section Four: Soil Properties. In depth explanations with public domain graphics.
Soil Biology Primer, Natural Resources Conservation Service, USDA.