Download - Soil Formation Notes
Soil
• The loose, weathered materials on Earth’s surface in which plants grow. • Soil is a mixture of rock particles,
minerals, decaying organic matter, water, and air.
Bedrock
• The solid layer of rock beneath the soil• When bedrock is exposed to Earth’s surface, it
weathers into soil
Humus
• Humus is the dark colored, decayed organic material in the soil.
Fertility
• Fertility is a measure of how well the soil supports plant growth
Loam
• Soil that is equal amounts of clay, sand, and silt is called loam.
Topsoil
• Topsoil is the top layer of soil. • Topsoil is also called the A Horizon of soil.• Topsoil is brown and crumbly, and is a mixture
of humus, clay, and minerals.
Subsoil
• Subsoil is made of clay and other particles that have been washed down from the A horizon.
• Subsoil is also called the B Horizon of soil.
C Horizon
• The C horizon contained partially weathered rock only.
Bedrock
• The bedrock layer is solid rock.
