Explain the term- pedon and polypedon

The characteristics of soil do not change vertically downwards only, there are lateral variations also as soil is a three dimensional body. Therefore, a three dimensional sample within a soil, called a  pedon, is chosen as a unit to represent the nature and arrangement of horizons and variability in the properties of soil.

A group of similar pedons that are surrounded on all sides by "non-soil" or by pedons of unlike character is called a  polypedon. A schematic s ketch of a soil pedon in relation to the soil, polypedon and soil profile is shown in Fig. In the following subsection you will study about the characteristics of profile of a given soil. It is important for the classification of the soil as well as in putting the soil to an appropriate use.