LFS:SoilWeb/Soil Classification/Pedogenesis

Pedogenesis is the study of the processes that lead to the formation of soil and was first explored by the Russian geologist Vasily Dokuchaev, the so-called grandfather of soil science, who determined that soil formed over time as a consequence of climatic, mineral and biological processes. In 1941 the Swiss scientist Hans Jenny expanded Dokuchaev’s findings by adding relief/topology as a factor of soil formation and separating the biological processes into the fauna and flora coming up with the equation:

Soil = f(C, PM, R, O, V, T)

where C = regional climate; PM = parent material; R = relief; O = fauna; V = biota; T = time.

Pedogenesis can be illustrated using the example of ecological theatre and the evolutionary play proposed by Hutchinson (1965). Soil forming factors can be envisioned as setting the stage or conditions for soil formation (the ecological theatre). The play that is enacted within the theatre is the processes that interact over time to modify the original solum. When we dig a soil pit, we peek into a moment taken from the play and view the imprint of all that has occurred up to that moment. Human intervention in the play can be either as actor or co-director, re-defining the plot and changing the scope of the theatre.

Pedogenesis is the relationship between soil forming factors and processes.

Soil formation factors and processes combine to affect the overall soil body, which is recognized and described as a pedon. The resulting soil properties (thickness, colour, texture, structure, chemical properties of horizons) are used to classify the soil. These properties, in combination with other land attributes and economic considerations, may be used to interpret soil suitability for particular uses. Monitoring soil changes through selected attributes (so called soil quality indicators) should be carried out periodically to determine soil quality and to provide feedback into management practices, so that the role of "director" in the evolutionary play is carried out responsibly. Also review Soil Quality.

Reference Hutchinson, G.E. (1965). The ecological theatre and the evolutionary play. Yale University Press, New Haven, CT: USA.