APES - MODULE 20 Unit 4 Test

igneous rock

form from magma

sedimentary rock

form from sediments are compressed over a long period of time

metamorphic rock

transformed rocks by intense heat, pressure

physical weathering

breakdown of rocks/minerals from water/wind/temperature variations

chemical weathering

breakdown of rocks/minerals by chemical reactions. ex: reactions w water, oxygen, etc…

what can dissolve rock?

acid rain

erosion

process of natural forces like water, wind, and ice breaking down and moving rocks and soil from one location to another

how does soil form?

• Climate

• Organisms

• land shape

• Parent Material (the original rock)

• Time

benefits of soil

• filters water

• help plant growth

• Habitat for a variety of organisms

• Breaks down organic material & recycles nutrients

soil horizons in order to (from top to bottom)

• O

• A

• E

• B

• C

• R

O HORIZON

organic matter (humus)

A HORIZON

topsoil (rich in nutrients and organic matter, that is vital for supporting plant growth)

E HORIZON

Leaching: process where a substance, such as a mineral or pollutant, is dissolved or washed away

B HORIZON

subsoil:mineral material with very little organic matter

C HORIZON

weathered rock: least-weathered soil horizon

R HORIZON

bedrock

soil erosion

from contact against wind and water, as well as increases in human activity, affects on topsoil

How is soil productivity characterized?

• water holding capacity

• nutrient availability

porosity

the air space of soil

permeability

ability of water to move through the soil

most permeable to least permeable

sand, silt, clay

cation exchange capacity (CEC)

ability of a particular soil to adsorb and release cations (+ charged ionsnutrients and ions commonly identified in soils)

nutrients and ions commonly identified in soils

• Nitrogen

• Phosphorus

• Potassium

• Calcium

base saturation

proportion of soil bases to soil acids – too many acids can be harmful to plant nutrition.

biological soil properties

fungi, bacteria, and protozoans (single-celled eukaryotes)