Download as a group

SOIL
WHAT IS SOIL?
• SOIL IS A MATERIAL THAT FORMS THE CRUST OF THE
EARTH.
• IT COMES FROM THE WEATHERING OF ROCKS AND
DECOMPOSITION OF ORGANISMS.
• IT IS FORMED VERY SLOWLY.
WHAT’S IN SOIL?
• MINERALS
• ORGANIC MATTER
• AIR AND WATER
• LIVING ORGANISMS
SOIL IS FOUND IN LAYERS
CALLED HORIZONS
SOIL-NOTICE THE
LAYERS IN THE SOIL
O HORIZON
(GREEN)
• O = ORGANIC
• THE TOP, ORGANIC LAYER MADE
UP MOSTLY OF LEAF LITTER AND
HUMUS.
• HUMUS IS DECOMPOSED
ORGANIC MATTER.
A HORIZON
(DARK BROWN)
• A = TOPSOIL.
• DARK COLORED
• WHERE SEEDS GERMINATE AND
ROOTS GROW. THIS IS
GENERALLY THE MOST
PRODUCTIVE LAYER OF SOIL.
B HORIZON
(LIGHT BROWN)
• B = SUBSOIL
• LIGHTER COLORED
• CONTAINS CLAY AND
MINERAL DEPOSITS (IRON,
ALUMINUM, ETC)
C HORIZON
(TAN)
• C = PARENT MATERIAL
• LAYER OF LARGE
UNBROKEN ROCKS
R HORIZON
(BLACK)
• R = BEDROCK.
• THE SOLID ROCK
THAT IS UNDER
THE SOIL
• AREAS WITH A
LOT OF
HUMUS AND
TOPSOIL ARE
GREAT FOR
GROWING
PLANTS.
Desert Soil
(hot, dry climate)
Grassland Soil
(semiarid climate)
Alkaline,
dark,
and rich
in humus
Mosaic
of closely packed
pebbles and
boulders
Weak humusmineral mixture
Dry, brown to
reddish-brown, with
variable accumulations
of clay, calcium
carbonate, and
soluble salts
Clay,
calcium
compounds
Forest litter
leaf mold
Acidic
lightcolored
humus
Humus-mineral
mixture
Light-colored
and acidic
Light, grayishbrown, silt loam
Iron and
aluminum
compound
s
mixed with
clay
Tropical Rain Forest Soil
(humid, tropical climate)
Acid litter
and humus
Humus and
iron and
aluminum
compounds
Dark brown
firm clay
Deciduous Forest Soil
(humid, mild climate)
Coniferous Forest Soil
(humid, cold climate)
SOIL LAB ONLINE
• TOMORROW YOU WILL MEET IN THE COMPUTER LAB (229) AND
COMPLETE A SOIL WEBQUEST.
• YOU WILL LEARN HOW RAINFALL AFFECTS TOPSOIL DEPTH.
REMAINDER OF THE PERIOD
• ANSWER THE REVIEW
QUESTIONS AS A
GROUP.
• USE THIS DIAGRAM TO
LABEL THE LAYERS
PICTURED IN #4. YOU
WILL STILL NEED TO
NAME AND DESCRIBE
THEM (EXCEPT LAYER E)