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Geology & Earth Sciences vocabulary · Soil

Soil horizon

Meaning in geology & earth sciences, with examples

nounCommon term

In geology & earth sciences, soil horizon means: One of the distinct layers in a soil profile, roughly parallel to the surface, that differs from the others in colour, texture or composition.

In Turkish: toprak horizonu, toprak katmanı

How it is used

Named with letters: O (organic layer), A (topsoil), E (leached layer), B (subsoil), C (weathered parent material) and R (bedrock). Students learn to say 'the B horizon is rich in clay'. Often shortened to 'horizon'.

Example sentences

  1. In this pit, the soil horizon below the topsoil is rich in clay.

  2. Each soil horizon is described by its colour, texture and thickness.

Common collocations

  • A horizon
  • B horizon
  • soil horizon boundary
  • organic horizon
  • soil profileA vertical section through a soil from the surface down to the rock beneath, showing its different layers, called horizons.
  • topsoilThe upper layer of soil, usually the top 5 to 30 cm, which is rich in organic matter and holds most plant roots and soil organisms.
  • humusThe dark, stable organic material in soil that forms when plant and animal remains decay. It holds water and nutrients and makes soil fertile.
  • clayVery fine mineral particles, smaller than about 0.002 mm in soil science, and the soft, sticky material they form when wet. Clay holds water and nutrients well.

More terms: Soil

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