A soil profile is a vertical section of soil from its surface downwards. Soils have layers called horizons. Each layer is different from the one above and below it.
1 1 A horizon 2 2 B horizon 3 C horizon 3
Draw your own labelled diagram to describe the layers in a soil profile.
The A horizon is sometimes called the topsoil. It is the top and most fertile layer of soil (closest to the surface), usually dark in colour because it contains the most humus and plant litter. The B horizon is called the subsoil. It is found just below the topsoil, has less humus and is lighter in colour than the top soil. It may contain more stones than the top soil as it is closer to the bedrock (C horizon). The C horizon can be called the bedrock. It is a mixture of solid rock at its base and smaller rock pieces at its top.
A typical soil profile
Two Impacts on Soil Formation
1 Leaching Hard pan
Leaching occurs when there is a high amont of rainfall. The water percolates (soaks) down through the soil and washes important minerals and nutrients down into the B horizon.
