A profile of a typical grassland soil reveals vertical horizons.
- A horizon is the topsoil rich in decayed organic material (humus).
- B horizon is the subsoil that accumulates nutrients leached from above.
- C horizon contains parent material (rock), low in organics.
Sitting on top is a litter layer of organic matter that has not decomposed (detritus).
After decomposition, this litter may be incoporated into the topsoil as humus.