Question

A soil profile with labels O, A, B, C. O: top layer. A: second layer. B: third layer. C: bottom layer.
Examine the soil profile and use the drop-down menu to select what each label identifies.
Label O

Label A

Label B

Label C

Answer 1

Label O: O horizon — organic layer (leaf litter, decomposing organic matter)

Label A: A horizon — topsoil (mineral soil mixed with humus; zone of root activity)

Label B: B horizon — subsoil (zone of accumulation of clay, iron, and minerals leached from A)

Label C: C horizon — parent material (partially weathered rock or unconsolidated material)