Visual Dictionary Online


Powered by

soil profileclick to hear

Soil usually has four main layers; it varies in total thickness from several inches to several feet, depending on the area.
soil profile bedrock subsoil plant litter topsoil

bedrock click to hear

Rock that forms the bottom layer of soil; its physical and chemical breakdown enables the upper layers to develop.

subsoil click to hear

Third layer of soil to which the roots extend; contains little organic matter but many nutrients leached from the topsoil.

plant litter click to hear

Upper layer of soil, composed of recently fallen animal and vegetable scraps or those in the early stages of decomposition.

topsoil click to hear

Second layer of soil, dark in color and rich in organic matter; it contains almost all of the soil’s animal and vegetable life.