Soils Glossary
- columnar: A type of soil structure where the soil peds (or chunks)
are in the shape of a column with a rounded top.
- dissolution: Soils, among other compounds, start dissolving into
smaller units when placed in contact with water.
- diurnal cycle: A daily cycle, a basic repetition period of 24 hrs.
All processes that are dominated by the sun are diurnal. Tides, in contrast,
repeat cycle twice daily.
- eluviation: The removal or "exit" of materials from one horizon
which are then "illuviated" into a horizon below.
- erosion: The removal and movement of soil materials by water,
wind, ice, or gravity, as well as by human activities such as agriculture
or construction.
- evaporation: Water on the Earth's surface or in the soil absorbs
heat from the sun to the point that it vaporizes or evaporates and becomes
part of the atmosphere.
- friable: A type of soil consistence in which the soil ped "pops"
when squeezed between the thumb and fore finger withjust a small amount of
pressure.
- gravimetric: A weight-based measurement. In our case, soil moisture
content is determined by a series of wet and dry weights.
- ground litter: the covering over the soil in a forest made up of
leaves, needles, twigs, branches, stems, and fruits from the surrounding trees.
- horizon: An individual layer within the soil which has its own
unique charateristics (such as color, structure, texture, or other properties)
that makes it different from the others in the soil profile.
- humus: The part of the soil profile that is composed of decomposed
organic matter from dead and decaying plants and animals.
- illuviation: The deposit of materials carried by water from one
horizon into another within the soil (such as clay or nutrients in solution).
- in situ: In (its original) place. Thus the difference between an
in situ and a laboratory soil measurement is that the first is made with
little or no disturbance in the original soil profile while the second
requires considerable mechanical agitation and change of environment to
remove a sample to location away from the place of origin.
- lithosphere: The outer layer of soil and rock on a planet is
called the "lithosphere" after the Greek word "lithos" meaning "stone".
- metadata: Data about data. Beyond (typical) data requirements.
Soil moisture data requires metadata describing the vegetation cover and
possible sources of water in order to be interpreted properly.
- nomenclature: A particular naming convention agreed to by many
individuals or scientists.
- organic matter: any plant and animal material added to the soil.
- particle size distibution: The amount (percent) of each of sand,
silt, and clay in a soil sample. When the percents of each of these are
added together, they should sum to 100%.
- ped: A unit or 'chunk' of soil made up of individual particles
of sand, silt, clay, and some organic material that stick together into a
specific structure.
- pedogenesis: The formation of soil profiles depending on the 5
soil forming factors (climate, parent material, topography, organisms, and
time) to create the Pedosphere.
- Pedosphere: The thin outer layer of the Earth which is made up of
soil. The pedosphere acts as an integrator between the atmosphere, biosphere,
lithosphere, and hydrosphere of the Earth.
- prismatic: A type of soil structure in which the soil ped is in
the shape of a prism.
- soil consistence: How easy or hard it is for a soil ped to break
apart when it is squeezed.
- soil horizons: An identifiable soil unit due to color, structure,
or texture.
- soil profile: The "face" of a soil when it has been cut vertically
that shows the individual horizons and soil properties with depth.
- soil structure: The shape of soil units (peds) that occur
naturally in a soil horizon. Some possible soil structures are granular,
blocky, prismatic, columnar, or platy. Soils can also be structureless if
they don't form into peds. In this case they may be a consolidated mass
(massive) or stay as individual particles (single-grained).
- soil texture: The way the soil "feels" when it is squeezed between
the fingers or in the hand. The texture depends on the amount of sand, silt,
and clay in the sample (particle size distribution), as well as other factors
(how wet it is, how much organic matter is in the sample, the kind of clay, ...)
- transect: In any field (outdoor) study, a transect consists of
a line of study, often divided into intervals where observations or
samples are collected.
- transpiration: Water in plants escapes or transpires into the
atmosphere as the leaf stomates open to exchange carbon for oxygen.
- uniform: this term is used in its traditional sense that some
characteristic displays similar properties. Two related words are
homogeneous (distributed evenly) and normal (distributed about a central
mean value and described by a statistical equation).
v. Jun. 4, 1996