ESM 120 Final

Calcification

accumulation of calcium carbonate in the subsoil. Calcium carbonate dissolves, because of carbonic acid (H2CO3) reacting with the calcium carbonate. Calcium carbonate then precipitates. This is common in deserts and dryer grasslands: arid environments (B climates). Soil orders: aridisols and mollisols.

Salinization

accumulation of soluble salts (ie NaCl, NaHCO3, gypsum (CaSO42H2O)). Occurs in arid environments because there's not enough water to leach out those salts. Soil orders: aridisols.

Spodosols

acidic soil order with subsurface accumulation of Al and Fe; occurs in the Taiga, mid-latitude forests,

B

arid climate

Aridisols

arid soils; occur in grasslands, deserts,

Csa

central valley climate (ie Davis)

CSb

coastal climate

BWk

cold desert climate

BSk

cold steppe climate, also cool grasslands

Melanization

darkening of the soil by the accumulation of decomposed organic matter (being decomposed by bacteria and fungi). (Humus is the decomposed organic matter). Typically in grasslands. Soil order: Mollisols.

Mollisols

fertile soil order, found in grasslands and some cold deserts

Alfisols

high fertility soil order, found in tropical savanna and mid-latitude forests

Gelisols

high latitude permafrost soil order; occur in the tundra

H

highland climate

Oxisols

highly weathered, fertile soil order with an accumulation of Iron and aluminum oxides; found in the tropical rainforest

BWh

hot desert climate

BSh

hot steppe climate

Cfa

humid temperate climate with hot summer

E soil horizon

light-colored, non-pigmented mineral particles formed by eluviation (which means to wash out soluble components)

C soil horizon

little or no alteration by soil-forming processes; can be soft or weathered bedrock or unconsolidated material, such as alluvium. Partially altered parent material.

Ultisols

low fertility soil order with subsurface clay accumulation; occurs in mid-latitude forests and tropical seasonal forests

C

mesothermal climate

D

microthermal climate

A soil horizon

mineral soil horizon mixed with organic matter (very decomposed organic matter)--dark because of the organic matter

Podzolization

"under ash." It has a gray-colored E horizon because it's strongly eluviated. Podzolization is the process by which iron and aluminum are stripped out of surface horizons and added to the B horizon. The movement of iron and aluminum under the influence of organic matter. Produces a Bs horizon. Occurs in cool, humid climates: the Taiga (Boreal forest). Soil orders: spodisols.

Lessivage

"washing out." Clay washes out from the surface to the subsurface. Clays are eluviated from the A and E horizon, and illuviated to the Bt horizon (t for tonne=clay). Occurs in the midlatitudes, typically in forested environments. Very common just away from the equatorial zone (where there is seasonal drying--because of the movement of the ITCZ). Not common in deserts, though, because it's not wet enough. So it's in more humid midlatitudes: forests, grasslands. Associated soil orders are alfisols and ultisols.

Af

"wet," tropical rainforest climate

R soil horizon

Unweathered parent material--hard bedrock

O soil horizon

organic material

Histosols

organic soils; found in the Taiga

E

polar climate

Vertisols

shrink-swell clay soils; found in the tropical savanna

Gleization

soil is becoming grey because of reducing conditions; the result of anaerobic respiration (anaerobic because the soil is saturated with water, so there is little oxygen). Electron acceptors are iron and manganese. Soil is saturated with water. Most commonly found in the tundra (because of the permafrost). Water sits there in the summer. (Gellisols are frozen soils)

Entisols

soil order with little soil development; occur in deserts

Andisols

soil order with volcanic ash influence

Inceptosols

soil order with weak soil development; found in midlatitude forests

B soil horizon

subsoil; soluble compounds accumulate here (that have been washed in); formed by illuviation

Laterization

the mobile constituents of the soil (like dissoved calcium carbonate) have leached out, leaving the iron and aluminum oxides (which have low solubility). Fe2O3. (Sesquioxides have one and a half oxygen atoms per metal atom). Aluminum oxides and Iron oxides accumulate. Found in the tropics, because there is so much precipitation that there is lots of leaching. It is leaving behind iron and aluminum sesquioxides! This soil order is called oxisols.

A

tropical climate

As

tropical climate with a dry season in the summer

Aw

tropical climate with a dry season in the winter

Am

tropical monsoon climate