Soil Unit Terminology List
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Required Terms:
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Acid Precipitation:
Rain, sleet, or snow that contains a high concentration of acids
due to air pollution
Bedrock:
Solid rock underlying soil
Chemical weathering:
During this process, the mineral composition of the rock is
changed due to the influence of water, oxygen, and carbon
dioxide.
Climate:
The average weather conditions in an area over time.
Desertification:
The process by which fertile land becomes desert, typically as a
result of drought, deforestation or unsustainable agricultural
practices
Differential Weathering:
The process by which softer, less weather resistant rocks wear
away and leave harder, more weather resistant rocks.
Erosion:
The carrying away of rock and soil particles by moving water, ice
and/or gravity.
Geologic History:
A measure of time used by geologists and other scientists to
describe the timing and relationships between natural events
which occurred in Earth’s history.
Ground water:
Water located beneath Earth’s surface, contained in the porous
spaces of soil and crevices of rock.
Humus:
Dark, organic material formed in soil from the decayed remains
of plants and animals
Infiltration:
The process by which water on the ground surface enters the
soil.
Inorganic:
Made from materials that were never living things
Land Degradation:
Reduction or loss of the biologic or economic productivity of
land, usually as a result of unsustainable land use.
Leaching:
The removal of substances that can be dissolved from rock, ore,
or layers of soil due to the passing of water.
Mechanical Weathering:
The breakdown of rock into smaller pieces by physical means.
Organic:
Made from materials that were once living (plants, animals)
Parent Rock:
A rock formation that is the source of soil
Permeability:
A rock that will allow water to pass through it such as limestone.
Porosity:
A measure of the ability of water to pass through a substance
because of tiny pores that allow fluids or gasses to pass through
Soil:
A loose mixture of rock fragments, organic material, water and
air that can support the growth of vegetation
Soil Conservation:
A method to maintain the fertility of soil by protecting it from
erosion and nutrient loss
Soil Fertility:
Soil with the characteristics to support life, including nutrient
content, acidity, and water.
Soil Horizons:
A layer in a soil profile.
Sustainable:
Conserving an ecological balance by avoiding depletion of
natural resources