Transcript soil overview

Soil
The Thin Layer Providing Life
What is soil?
• Layer on the earth’s crust that provides a
combination of resources.
What is the importance of soil?
• Soil forms a very
thin interface
between the
continental crust,
which is about 50
miles thick, and
the atmosphere,
which is about 170
miles deep.
How does soil help support life?
• The atmosphere, crust, and soil
interact to provide these nutrients.
▫ Proper oxygen
▫ Proper temperature
▫ Water
▫ Carbon
▫ Other various nutrients
How does soil help support life?
• Oxygen—needed for adequate root
growth.
• Temperature—determined by the
amount of heat the soil absorbs from
the sun and the amount it loses to
the atmosphere. Temperatures
within a particular range are needed
for plant growth and seed
germination.
How does soil help support life?
• Water—utilized for growth of plants.
• Carbon—utilized in the form of organic
matter in the soil.
• Nutrients—provided as minerals.
Nitrogen is one mineral made available
and recycled through decaying material
in the soil.
How does soil help support life?
• Anchorage
▫ Helps to
hold plants
in place so
they can
grow
Soil Components
• Solid portions (50 percent of soil volume)
▫ Mineral matter
 45 percent of the soil
 Inorganic material originating from rock.
 Determine the soil’s ability to hold water and
provide nutrients
 Sand, silt, and clay
▫ Organic matter
 5 percent of the soil
 Partially decomposed plant and animal matter
 Contributes to the soil’s fertility as well as improved
aeration and water-holding capacity
 Gives soil its dark color
Soil Components
• Pore space (50 percent of soil volume)
▫ Air
 25 percent of the soil
▫ Water
 25 percent of the soil
 When it rains, water will enter the soil or flow off the
soil’s surface.
• There is a constant fluctuation in the amount of
air and water found in the soil.
Living Organisms Found in Soil
• Forms of life in soil include:
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Earthworms
Insects
Bacteria
Fungi
Other organisms
Bacteria and Fungi
• Break down organic matter and release
nutrients
• Have symbiotic relationships with plants.
▫ Symbiosis is the living together of unlike
organisms where both organisms benefit.
 fungi get glucose and sucrose from plant roots
 plants are assisted in the absorption of water and
minerals
Animals and Insects
• Earthworms, ants, crawfish, moles, and other
organisms improve the soil tilth (the ease with
which soil can be worked).
▫ create openings in the soil as they tunnel
▫ enhances drainage and improves air exchange