Soil Processes

Soil formation (genesis) is brought about by a series of specific changes that can be grouped into four broad soil processes as noted in the image below:

Additions:

Addition of material to the developing soil profile from outside sources, such as organic matter from leaves, dust from the atmosphere, or soluble salts from groundwater. Click the links to below to view the video clips:

a. organic examples

b. mineral example

Translocations:

Translocation (transportation) of inorganic and organic materials from one horizon to another, either up or down (material is primarily moved by water but may also be moved by soil organisms). Click the links below to view the video clips:

a. pedoturbation

b. clay accumulation
c. argillipedoturbation
d. cryoturbation
e. elluviation and illuviation

Transformations:

Transformation of soil constituents from one form to another, such as through mineral weathering and organic matter breakdown. Click the links below to view the video clips:

a. example in a Gleysol
b. example in a Brunisol

Losses:

Loss of material from the soil profile by leaching to groundwater, erosion of surface material, or other forms of removal (often transformation and translocation result in the accumulation of material in a particular horizon). Click the link below to view a video depicting erosion of an Organic soil.

These processes of soil genesis, operating under the influence of environmental factors, give us a logical framework for understanding the relationships between particular soils and the landscapes and ecosystems in which they function.

This approach is known as internal process modeling. In analyzing these relationships for a given site, ask yourself the following four questions:

  1. What are the materials being added to this soil?
  2. What transformations and translocations are taking place in this profile?
  3. What materials are being removed?
  4. How have climate, organisms, topography, and parent material at this site affected these processes over time?