Transcript Composition of Soil

Composition of Soil
By: Stephanie Bales,
Kelley Fox, and
Courtney Dunford
• Soil comes from rocks, minerals, and organic
materials
• Components of soil: mineral matter, air, water,
organic matter
• Cause of soil erosion: water, wind,
no vegetation
Words To Know
• Clay: fine grain soil that is pliable when moist but
hardens as it is heated
• Compost: decomposed organic material
• Loam: a soil containing clay, sand, silt and organic
matter
• Metric system: a system of measurement based on
powers of ten
• Sand: loose particles of broken rock
• Silt: particles of rock slightly larger than clay but
smaller than sand
• Topsoil: upper layer of soil, plant roots are typically
found here
Rock Material
• Stone, sand, silt and clay
• Comes from “parent rock”
• Parent rock determines the chemical back
bone of the soil
• It also determines the grain size
• Topography, time and climate effect
composition and the breakdown of the rock
• It may appear as pebbles, gravel, or as small
as particles of sand or clay.
Organic Material
• Plants, animals, fungi, bacteria and humans affect the
composition of the soil
• Decaying of once-living organisms (plants or insects)
• Fungi and bacteria affect the exchange of nutrients
between plants and soil
• Humans remove vegetation which causes erosion.
• This is plants or animals that have died and decayed
until they become part of the soil.
The amount of water in the soil is closely
linked with the climate and other
characteristics of the region. The amount of
water in the soil is one thing that can affect
the amount of air. Very wet soil like you
would find in a wetland probably has very
little air. The composition of the soil affects
the plants and therefore the animals that can
live there.
Layers of Soil
• Defined by color, size, texture, structure,
consistency, root quantity, ph and other
factors
5 Layers
• Top Layer – “O” – Organic
– Found in forest soils
– Made of dead leaves and debris
• 2nd Layer – “A” – Organic Material is mixed with Inorganic
Material
– Usually darker, and if it’s tere means the soil is fertile for plants
• 3rd Layer – “E” – result of acidic water running through 1st 2
layers
• 4th Layer – “B” – Minerals an clay grains accumlte here – can
be thick and tight – difficult for water to penetrate
• 5th layer – “C” – contains the parent inorganic material (rock)
• If there wasn’t soil there wouldn’t be plant life on the
surface of the land
Stages in the Formation of Soil
Stage 1
Stage 3
Stage 2
Stage 4