LFS:SoilWeb/Soil Classification/Soil Formation Processes

Soil formation (genesis) is brought about by a series of specific changes that can be grouped into four broad processes:

• Additions: Addition of material to the developing soil profile from outside sources. Examples of added material include organic matter from leaves and roots, dust from the atmosphere, and soluble salts brought into the soil by groundwater.
• Losses: Loss of material from the soil profile by leaching to groundwater, erosion of surface material, or other forms of removal.
• Translocations: Translocation or transportation of inorganic and organic materials from one horizon to another, either up or down. Within the soil profile, material is primarily moved by water but may also be moved by soil organisms (e.g., earthworms, ants) or through events such as windthrow.
• Transformations: Transformation of soil constituents from one form to another, such as through mineral weathering and organic matter breakdown.

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:

• What are the materials being added to this soil?

• What transformations and translocations are taking place in this profile?

• What materials are being removed?

• How have climate, organisms, topography, and parent material at this site affected these processes over time?

RELATED LINK: Soil Formation and Soil Processes, VSSLR This resource provides students with interactive, video and text-based information to assist them in understanding soil formation concepts. It features examples of soil processes, from each of the four groups, that occur in some soil types in British Columbia. In addition, the resource also allows students to relate soil formation to various management issues as presented in introductory soil science courses.