Soil
The part of the regolith that supports the growth of plants.
Regolith
The layer of rock and mineral that covers most of Earth's land surface.
Soil Horizons
Layers of soil.
Soil Profile
The vertical section through all the soil horizons.
O horizon
Organic materials (Humus).
A horizon
Topsoil, mineral with humus.
E horizon
Eluviation, leached mineral and little organic.
B horizon
Subsoil, considered as the zone of accumulation.
C horizon
Parent rock, partially altered parent and weathered material.
R horizon
Bedrock, unweathered parent material.
Soil Conservation
Keeping soil healthy by preventing erosion and using smart farming techniques.
Crop Rotation
The practice of planting different crops on the same field in different years or growing seasons.
Conservation Tillage
Disturbing the soil less when planting to keep it in good shape and prevent erosion.
Terraces
Flat areas built on a hillside to hold rainwater and prevent it from running downhill.
Counter Plowing
Channeling rainwater to prevent it from running straight downhill and carrying away soil.
Wind Breaks
Rows of trees planted between fields to break or reduce the force of winds that can carry off soil.
Mechanical Weathering
Causes rocks to crumble, often through the actions of water, frost wedging, abrasion, pressure, and expansion/contraction.
Frost Wedging
Physical weathering that breaks down rocks through the freezing and thawing process.
Abrasion
The physical process of rubbing, scouring, or scraping whereby particles of rock are eroded away by friction.
Pressure
The propagation of fractures near the surface of solid rock due to expansion related to the release of confining pressure.
Expansion & Contraction
Rocks expand when heated and contract when cooled due to daily and yearly cycles of heating and cooling at Earth's surface.
Biological Weathering
Weathering caused by plants and animals.
Chemical Weathering
Results from chemical reactions between minerals in rocks and external agents like air or water.
Dissolution
Some minerals dissolve in water while others do not.
Hydrolysis
Water reacts with a mineral to form a crystal structure.
Oxidation
The reaction of rock minerals with oxygen.
Carbonation
The process where rock minerals react when carbon dioxide and water combine to form carbonic acid.