If enough of the topsoil blows or washes away we are left with subsoil . The subsoil is the layer below the topsoil. It is usually lighter in color and less productive than topsoil. Utah Agriculture in the Classroom Minerals here are not in a form that are easy for plants to use. The subsoil is mostly made up of clay or sand and has very little organic material.
Plants grow poorly in subsoil.
That's why farmers must work hard to conserve their topsoil. Between the subsoil and the bedrock is a layer of small rocks that have started to break off the bedrock. This layer is called the parent material of the soil. That is because most of what makes up the soil was once part of the rock.