Transcript Soil Layers - Harperclass

What Are Some Types of
Soil?
Third Grade
Humus
The part of soil made
up of broken down
pieces of dead plants
and animals
Sand
Soil with grains of rock
that you can see with your
eyes alone.
Silt
Soil with grains of rock that are too small
to be seen with your eyes alone.
Clay
Soil with very, very
tiny grains of rock.
(has smallest grain of rock)
• The main difference between sand,
silt, and clay soils is their grain
size. They are also made up of
different minerals.
• Smallest to largest rock particles.
clay, silt, sand
Loam
Soil that is a mixture of
humus, sand, silt, and
clay.
Most soils found on farms
are loam.
Soil Layers
Topsoil
Subsoil
Bedrock
Topsoil
Topsoil has a lot of humus.
Many small animals, such as
ants and earthworms, live in
topsoil
Subsoil
The layer underneath
topsoil. Subsoil does
not have a lot of
humus, but it does have
small rocks in it.
Bedrock
If you dig deep enough into the soil,
you will reach solid rock. This solid
rock is called bedrock. Most small
rocks in soil come from the bedrock
underneath it.
All soils have water, humus, air,
and small pieces of rock.
• Soils are different by colors,
textures, rock sizes, and
different abilities to hold water.
How Do Rocks
and Soil
Change?
Weathering
The breaking down of
rocks into smaller pieces.
Example: rocks splitting
Erosion
The movement of
weathered rock and
soil.
Examples of erosion
• A river carries soil away.
• Wind blows sand from a sand dune.
• The ocean knocks over a sand castle.