SoilJordan Del Guercio

Ryan Lee

Matt Jun

Nick Tang

APES Per. 5

Importance of Soil• provides physical support and nutrients

for plants, allowing them to live

• greatly affects both above-ground and below-ground ecology

• above-ground usually affects plants

• below-ground affects organic matter and decomposers

Earth’s Spheres• lithosphere – inorganic, rocky

crust

• hydrosphere – water

• biosphere –all living organisms

• atmosphere – air that surrounds planet

• each sphere contains a different amount of soil

Amount of Soil• lithosphere – soil is present, but it lacks nutrients and minerals

• hydrosphere – none

• biosphere – soil is present to support living organisms such as plants

• atmosphere – none

Soil Formation• soil forms

spontaneously from rock, which fragments as a result of heat, cold, wind, rain, hail and ice

• it is formed under high temperature and pressure

Factors of Soil Formation

• climate

• topography

• organisms

• time

• parent material

Climate• the quality of soil at the end of the soil formation process depends on the climate

• temperate regions: able to absorb nutrients, swells under moisture

• hot/humid regions: arable but easily dried, not able to hold nutrients

• cold regions: soil is similar to sand

Soil in a Temperate Climate

• contains minerals and nutrients that help plants grow

Soil in a Humid Climate

• easily dried, not able to hold minerals or nutrients

Topography• steepness of the soil’s location can affect runoff of water and vegetation

• parent material needs to lie undisturbed

Parent Materials• Geological material where soil horizons

form, made of weathered minerals

• Physical weathering: materials are broken down, usually occurs due to temperature

• Chemical weathering: parent material releases minerals and nutrients

Soil Structure• O-Horizon – where the nutrients come

from

• A-Horizon – nutrients absorbed by lower horizons, rich in organic matter

• B-Horizon – where nutrients are accumulated

• C-Horizon – withered soil

• R-Horizon – unexposed parent material

Loam• mixture of sand, silt and clay

• 40% sand, 40% silt, 20% clay

Loss of Soil• produced naturally at a rate of  1mm in 200-400 years

• soil is currently being lost as much as 40 times as much of its natural replacement rate

Desertification•Desertification is the persistent degradation of dryland ecosystems by climatic variations and human activities

Desertification•Desertification occurs as a result of a long-term failure to balance human demand for ecosystem services and the amount the ecosystem can supply

Causes of Desertification

•Poor management of agriculture•Globalization•Population growth

•Desertification effects a wide range of services provided by ecosystems to humans

Effects

Such as: food and water, climate regulation, and soil conservation

Sediments

• Soil erosion occurs when particles are transported down-hill towards ever faster flowing rivers

• In slowly moving waters, silt and sand are deposited with some mud, creating very fertile soil.

• In the sea, thick layers of sediment are formed as water is squeezed out and the sediment compacted to form sedimentary rocks.

The End of the Soil Cycle

• When subjected to extreme pressure, by being pushed deep down, or by colliding forces, sediment rock will metamorphose into new, harder rock forms like gneiss, schist, greywacke and marble. These weather like the original igneous rocks, to form sand, silt and clay.

Works Cited