Lecture 9 Pedogenic Processes and Soil Horizons

Flashcards covering key concepts related to pedogenic processes and soil horizons, including definitions and important terms.

Pedogenesis

The process of soil formation.

Pedology

The study of the formation, characteristics, and distribution of soils.

Eluviation

The removal of soil material in suspension or solution from the upper soil profile.

Illuviation

The accumulation of soil material from upper soil horizons by the movement of water.

Transformations

A pedogenic process involving the chemical or physical modification of soil constituents.

Translocations

The movement of organic and inorganic materials within or between soil horizons.

Additions

Inputs of materials to the soil profile from outside sources.

Losses

The removal of materials from the soil profile due to various processes.

A Horizon

The layer at or near the surface formed by the addition, mixing, and transformation of organic matter.

B Horizon

The layer that has undergone substantial modification from the original parent material.

C Horizon

The horizon that resembles the parent material with little to no soil formation.

A horizon suffixes

Suffixes used to describe additional features of the A horizon, including Ap, Ah, Ae.

B horizon suffixes

Suffixes used to describe additional features of the B horizon, including Bt, Bn, Bm.

C horizon suffixes

Suffixes used to describe additional features of the C horizon, including Cca, Ck, Cg.

Organic Horizons

Horizons that contain 17% or more organic carbon and form in wetlands.

Oi, Om, Oh

Classification of organic horizons according to their degree of decomposition.

L, F, H

Classification of organic horizons in well-drained sites; L is litter, F is fermented, H is humic.

Horizon Ap

disturbed by human activities, top layer

Horizon Ah

rich with organic material

Horizon Ae

eluviation horizon, where minerals and nutrients are leached from the soil. Lighter in color, platy structure

Horizon Bt

enriched with clay due to illuviation. Forms below Ae

Horizon Bn

accumulation of sodium, prismatic or columnar structure

Horizon Bm

minimally altered

Horizon Bf

iron enriched

Horizon Cca

enriched with carbonates

Horizon Ck

contains Ca and Mg (limestone)

Horizon Cg

evidence of mottling and gleying due to water saturation

Chernozem, Vertisol, Solonetz

Grasslands soil classification

Luvisol, Brunisol, Podzol

Forest soil classifications

Gleysol, Organic

Wetlands soil classifications

Regosol

undeveloped soil

Cryosol

Tundra

Chernozem diagnostic horizons

Ah, Ap, Ae

Vertisolic diagnostic horizons

Bss or Css (slickensides), Bv (vertic horizons

Solonetz diagnostic horizons

Bn, Bnt

Luvisol diagnostic horizons

Bt

Brunisol diagnostic horizons

Bm

Podzol diagnostic horizon

Ae and Bf

Gleysolic diagnostic horizons

Bg, Cg

Organic diagnostic horizons

O

Regosolic diagnostic horizon

no B horizon

Cryosolic diagnostic horizons

By, Cy, Cz