Question

Explain the four main horizons in a soil profile.

Answer 1

Four main horizons

1. O-horizon: Surface layer of fresh and recognisable dead organic matter (litter); very rich in life.
2. A-horizon (topsoil): Mineral layer with roots and partly decomposed organic matter (humus).
3. B-horizon (subsoil): Contains iron and aluminium compounds, clay and humus. The A and B horizons together form the true soil.
4. C-horizon: Less-weathered parent rock material.