APES Unit 4

What is soil comprised of?

Humus (organic parts), nutrients, water, air, and living organisms

What are the 4 soil horizons?

O-Horizon: Layer of nutritious organic material above soil

A-Horizon: Topsoil made of humus and minerals from the parent material

B-Horizon: Subsoil layer of minerals with little organic matter

C-Horizon: The least weathered layer closest to parent material

What are two causes of soil degradation?

A loss of topsoil from tilling/lack of vegetation, or the compaction of soil casued by machines/livestock/humans

What are the three particles that make up soil in order from largest to smallest in size?

sand, silt, clay

What are factors that increase nutrient availability in soil?

Organic matter, decomposers, clay, bases, humus

What are factors that decrease nutrient availability in soil?

Acids, excessive water, excessive farming, topsoil erosion

What are factors that increase H2O holding capacity in soil?

Aerated soil, compost, clay, root structures

What are factors that decrease H2O holding capacity in soil?

Compacted soil, topsoil erosion, sand, root loss

What are the layers of the Earth’s atmosphere, from closest/most dense to farthest/least dense?

Troposphere, Stratosphere, Mesosphere, Thermosphere, Exosphere

What is Insolation?

The amount of exposure to the sun’s rays that an area receives

Which area of Earth has higher insolation? Why?

The equator has higher insolation because the sun’s rays strike it perpendicularly due to the Earth’s tilt, creating concentrated energy in one point.

What is the difference between a Solstice and an Equinox?

A solstice occurs when the Northern (June) or Southern (December) Hemisphere is at its most tilted point towards the sun and an equinox occurs when neither hemisphere is facing the sun more than the other.

What does it mean to have a high or low albedo?

A surface with a high albedo is able to reflect more light while a surface with low albedo absorbs more light.

What is the rain shadow effect?

When warm, moist air from the ocean travels up the windward side of a mountain, and moves down the other side of the mountain as dry air. This causes one side of the mountain to have lush vegetation while the other side experiences desert conditions.

What are the characteristics of the El Nino Southern Oscillation?

Trade winds are weaken and reverse directions going from West to East, upwelling is suppressed on the West Coast of South America, leading to hotter and drier conditions in Australia

What are the characteristics of the La Nina event?

Trade winds are much stronger than normal, upwelling is increased on the West Coast of South America, leading to warmer and rainier conditions in Australia