Label a Soil Profile - Worksheet | Teach Starter - Free Printable

The soil profile worksheet shows a cross-section of soil with distinct layers. I need to identify the standard soil horizons from top to bottom and match them to the visual representations in the diagram.

Let me work through this step by step:

1. Top layer (Layer 1): Shows plants, grass, roots, and organic matter on the surface. This is the O Horizon (Organic Layer) or sometimes combined with the A Horizon. It contains leaf litter, decomposing plant material, and living organisms.

2. Second layer (Layer 2): Shows darker soil with some roots extending down and small organisms/worms. This appears to be the A Horizon (Topsoil). It's rich in organic matter mixed with mineral soil, dark in color, and where most plant roots grow.

3. Third layer (Layer 3): Shows lighter colored soil with small particles/dots. This is the B Horizon (Subsoil). It has less organic matter, more clay and mineral deposits that have leached down from above. It's typically lighter in color than the A horizon.

4. Fourth layer (Layer 4): Shows larger rocks and stones with some soil between them. This is the C Horizon (Parent Material). It consists of partially weathered rock and mineral material that hasn't been fully broken down into soil yet.

5. Bottom layer (Layer 5): Shows solid bedrock/large rocks. This is the R Horizon (Bedrock). It's the solid rock layer beneath all the soil layers.

Now let me verify this against standard soil profile knowledge:
- O Horizon: Organic matter, leaf litter (topmost)
- A Horizon: Topsoil, dark, rich in organic matter
- E Horizon: Eluviation layer (sometimes present, light colored) - may not be shown here
- B Horizon: Subsoil, accumulation of minerals
- C Horizon: Parent material, weathered rock
- R Horizon: Bedrock

Looking at the image again:
- Layer 1 (top): Plants/grass/roots visible → O/A Horizon
- Layer 2: Darker soil with worms/roots → A Horizon (Topsoil)
- Layer 3: Lighter speckled soil → B Horizon (Subsoil)
- Layer 4: Rocky with some soil → C Horizon (Parent Material)
- Layer 5 (bottom): Large solid rocks → R Horizon (Bedrock)

For coloring guidance:
- O/A Horizon (top): Dark brown/black (rich organic matter)
- A Horizon: Dark brown
- B Horizon: Lighter brown/tan/reddish
- C Horizon: Gray/light brown with rocks
- R Horizon: Gray/solid rock color

Final Answer:

Soil Profile Layers (from top to bottom):

1. O Horizon / A Horizon (Top Layer) – Contains plants, grass, roots, and decaying leaves. Color this layer dark brown or black.

2. A Horizon (Topsoil) – Rich, dark soil with roots and small organisms like worms. Color this layer dark brown.

3. B Horizon (Subsoil) – Lighter-colored soil with fewer roots; minerals collect here. Color this layer light brown or tan.

4. C Horizon (Parent Material) – Mostly broken-up rock with some soil. Color this layer gray or light brown with rocky texture.

5. R Horizon (Bedrock) – Solid rock at the very bottom. Color this layer gray.