Unit 21: Formation of Soils

Soil regime

A set of environmental conditions that occurs over substantial areas and favors certain processes of soil formation.

Soil air

Air that fills the spaces among the mineral particles, water, and organic matter in the soil; often contains more carbon dioxide than atmospheric air does.

The process of illuviation adds particles in the ____ layer

B

Which layer best represents the weathered bedrock layer

C

Soil profile

Entire soil horizons from top to bottom.

Transported parent material

Material deposited by wind, water, mass movement, or glacier ice.

Soil

Mixture of fragmented and weathered grains of minerals and rocks with organic matter and variable proportions of air and water, has a fairly distinct layering or horizonation, its development is due to processes that are active just below a vegetation-covered land surface.

Which of the following soil horizons when reading from left to right indicate the correct order from top to bottom

O, A, E, B, C, R

Renewable resource

One that can regenerate as it is exploited.

Nonrenewable resource

One that with continued use will ultimately be exhausted (metallic ores and petroleum are good examples).

Parent material

Rocks of the Earth, and the deposits formed from them, from which a soil has formed.

Transformation

Soil formation process involving the weathering of rocks and minerals' decomposition of organic material, or other changes in the materials already present in a particular soil horizon.

Residual parent material

Soil parent material that is formed in place though weathering of the local bedrock.

Illuviation

Soil process in which downward-percolating water carries dissolved material and colloid-sized particles of organic matter and minerals into the B horizon, where these materials are deposited in pore spaces and against the surfaces of soil grains.

Addition

Soil-layer formation process involving the addition of matter to the soil, added can be organic matter from plants, dissolved ions in rainfall, dust particles from the air, and sediment eroded from soils farther uphill.

Soil horizon

Zone in a soil that is more or less parallel to the ground surface and differs from other horizons above and below it in terms of texture, color, structure, or other properties. The differentiation of soils into horizons is called horizonation.

The soil resides at the intersection of which spheres

atmosphere, lithosphere, lithosphere, hydrosphere, biosphere, lithosphere

The process of transporting particles from a higher layer to a lower layer is called ____.

eluviation

A soil profile shows a sequence of layers called ___.

horizons

Decomposed organic matter form a dark, top layer of soil is called

humus

Depletion

oil-layer formation process involving the loss of soil components as they are carried downward by water, plus the loss of other material in suspension as the water percolates from upper to lower layers

Where would soil formation be relatively rapid

on a tropical volcanic island.

Soil is a(n) ____ resource

renewable

Which of the following is NOT a component of soil

rocks

Eluviation

soil process that involves downward transportation of dissolved material and microscopic, colloid- sized particles of organic matter, clay, and oxides of aluminum and iron, usually from A or E horizons into B horizons.

Steep-sided mountainous soils tend to be ____ in depth.

thin

Which of the following is NOT a major factor in soil formation

tractors

The soil formation process involving the introduction of dissolved and suspended particles from upper layers into lower ones is called

translocation

Parent material of soil is generally

weathered bedrock