Formation of Soils from Parent Materials

A set of vocabulary flashcards based on the lecture on soil formation and classification.

Pedogenesis

The process of soil formation, which begins when horizons not present in the parent material start to appear in the soil profile.

Genetic Horizon

A distinct layer in the soil profile that has a specific significance in soil formation and classification.

Four Basic Processes of Pedogenesis

Losses, Translocations, Additions, and Transformations that contribute to soil development.

A Horizon

The topsoil layer, rich in organic matter, darker due to minerals and organic materials.

E Horizon

A zone of intense leaching where clay, Fe, and Al-oxides are eluviated, leaving larger particles and resistant minerals.

B Horizon

The subsoil layer characterized by accumulation of minerals and less organic matter compared to the A horizon.

C Horizon

The regolith layer, which is unconsolidated material that resembles the parent material with minimal alteration.

R Horizon

The consolidated bedrock layer, unaltered parent material, and typically impermeable.

Master Horizons

The primary soil layers that distinguish the vertical order of soil profiles: O, A, E, B, C, R.

Illuviation

The process of accumulation of material (like clays or minerals) in a lower horizon after being leached from upper horizons.

Eluviation

The process of leaching out of soluble substances like clay and minerals from the topsoil.

Soil vs. Sediment

Soil is a dynamic system that supports plant life and consists of organic and inorganic components, whereas sediment is composed of particles that have been weathered from rocks and do not necessarily support life.

Organic Layer (O Horizon)

Layer of organic material, primarily consisting of undecomposed to partially decomposed plant materials.

Lowercase Letter Symbols

Subordinate distinctions within master horizons indicating various specific characteristics (e.g., 'a' for decomposed organic matter).