Transcript (rock, sand, clay, silt), air, water, and organic material.

The product of
weathering
Soil is the loose
top layer of our
planet's crust. It is
dirt in which plant
life can grow
Made up of minerals (rock, sand,
clay, silt), air, water, and organic
material.
When a plant or animal dies, it
is broken down leaving
behind organic material
The decay left behind from
non-living things like rocks
Soil is formed slowly as rock is
weathered into tiny pieces and
mixes with the organic and
inorganic material.
Weathering, erosion, and
decomposition of animals and
plants continue to happen until
the soil is mature
Mature soil is made of
layers called horizons
They range from organic
upper layers to rocky
layers underneath
4 Soil Horizons:
•O Horizon
•A Horizon
•B Horizon
•C Horizon
2 inches down
Top, organic layer
of soil, made up of
leaves and humus
(decomposed
organic matter)
10 inches down
Called topsoil;
plants root and
grow here; made
of humus and
rock
30 inches down
Called subsoil;
usually broken up
when water from
A horizon moves
through it
40 inches down
Called
substratum;
contains
weathered
bedrock; mostly
rock
2 inches down
Top, organic layer of soil,
made up of leaves and
humus (decomposed
organic matter)
10 inches down
Called topsoil; plants root
and grow here; made of
humus and rock
30 inches down
Called subsoil; usually
broken up when water from
A horizon moves through it
40 inches down
Called substratum;
contains weathered
bedrock; mostly rock