What is a soil horizon?

Soil not only varies over the surface, but also changes as you dig deeper into the ground. Soil horizons are layers of soil that are approximately parallel to the surface.

These layers differ from other layers in physical, chemical and/or biological properties. Up to six horizons may be recorded for each soil component. This is true whether we are using SSURGO soils data or STATSGO soils data.

The map unit shown has been tilted back so that we can see the soil layers under the surface. Note that the different components each have different layers.