A loose
soil constituent composed of
grains of rock and minerals with diameters ranging between 0,05 mm
and 2 mm.
Sand is larger than silt
and smaller than gravel.
Sand is a naturally occurring granular and unconsolidated
material of very diverse
composition, found on beaches, in
deserts, and in soil, resulting
principally from rock disintegration composed by finely divided rock,
especially quartz (that may include
disintegrated shells and coral).
Sand ranges in diameter from 0,05 mm (very fine) to 2 mm (very coarse).
An individual particle in this range size is termed a sand grain.
The next smaller size class is silt:
particles below 0.05 mm down to 0.005 mm in size. The next larger size
class above sand is gravel, with
particles ranging up to 64 mm.
(2) Sand
[ Geography ]
A tract of land covered
with sand, as a beach or desert.
Often used in the plural.
Sandy
(Adjective)
Synonym: Arenaceous
Resembling or containing
sand; or growing in sandy areas.
Course textured, granular
soil, in consistency. Describes
dry, light, friable, large-grained and free-draining
soil, low in nutrients,
derived from quartz or other
rock.
Because of the relative large size of sand particles (0.05-2.0 mm),
sandy soils have trouble holding water
and nutrients. They are commonly
deficient in calcium and
magnesium. Adding
humus to sandy soils can help. When
mixed with a heavier soil (one
that is largely comprised of clay),
sand can help provide aeration.
Sand is also commonly mixed with seed for broadcasting and is a
component in some potting-mix.. Most sand grains consist of
quartz.
As a soil textural class,
a sandy soil has more than 85% of sand and not more than 10%
clay.
Some species of climbing
plants develop holdfast roots which help to support the vines on
trees, walls, and rocks. By forcing their way into minute pores and
crevices, they hold the plant firmly in place.
Climbing plants, like the poison ivy (Toxicodendron
radicans), Boston ivy (Parthenocissus
tricuspidata), and trumpet creeper (Campsis
radicans), develop holdfast roots which help to
support the vines on trees, walls, and rocks. By forcing their
way into minute pores and crevices, they hold the plant firmly
in place. Usually the Holdfast roots die at the end of the first
season, but in some species they are perennial. In the tropics
some of the large climbing plants have hold-fast roots by which
they attach themselves, and long, cord-like roots that extend
downward through the air and may lengthen and branch for several
years until they strike the soil and become absorbent roots.
Major references and further lectures:
1) E. N. Transeau “General Botany” Discovery Publishing House,
1994
