Question

Arrange the following soil horizons as they occur from top to bottom in a typical soil profile.
A. A horizon
B. B horizon
C. R horizon
D. O horizon
E. C horizon

• A. A, B, C, D, E
• B. D, A, B, E, C
• C. C, E, B, D, A
• D. A, B, E, C, D

Hint:

A simple mnemonic for the main soil horizons from top to bottom is "Old Ants Eat Big Crumbs of Rock". (O, A, E, B, C, R).

Answer 1

The Correct Option is B

Step 1: Identify the fundamental soil horizons. Soil scientists categorize soil into layers called horizons, each identified by a letter.

Step 2: Arrange the horizons from top to bottom.

1. O horizon: Surface layer abundant in organic matter (leaf litter, humus).

2. A horizon: Topsoil, combining minerals and humus; a zone of leaching.

3. E horizon: (Not always present, but often found beneath A): A zone of eluviation (leaching).

4. B horizon: Subsoil, where minerals and clays accumulate (illuviation).

5. C horizon: Parent material, consisting of weathered bedrock.

6. R horizon: Bedrock, the original, unweathered rock.

Step 3: Arrange the horizon sequence using the provided letters. The proper sequence, from top to bottom, is D (O horizon), A (A horizon), B (B horizon), E (C horizon), C (R horizon).