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: Define the master soil horizons.
Soil scientists classify soil into layers or horizons. The main (master) horizons are designated by letters.

Step 2: List the horizons in order from the surface downward. 1. O horizon (D): The surface layer, rich in organic matter (leaf litter, humus). 2. A horizon (A): Topsoil, a mix of minerals and humus. Zone of leaching. 3. E horizon (not in this specific list, but often present below A): Zone of eluviation (leaching). 4. B horizon (B): Subsoil, zone of accumulation (illuviation) where minerals and clays from above are deposited. 5. C horizon (E): Parent material, weathered bedrock from which the soil is formed. 6. R horizon (C): Bedrock, the unweathered parent rock.

Step 3: Form the sequence based on the given letters. The correct order from top to bottom is D (O horizon), A (A horizon), B (B horizon), E (C horizon), C (R horizon).