weathering		a mixture of rock particles, minerals, decayed organic materials, water and air
erosion		same processes that operate today operated in the past
uniforitarianism		the removal of rock particles by wind, water,
mechanical weathering		a crumbly dark brown soil that is a mixture of humus, clay, and other minerals.
abrasion		grinding away of rock particles carried by water, ice, wind and gravity
ice wedging		a farmer plants different crops in a field each year
chemical weathering		the process that breaks down rock and other substances at Earth's surface
oxidation		Rock is phyically broken into smaller pieces
permeable		the tick mass of though roots at the surface of soil
soil		means that material is full of tiny, connected air spaces that allow water to seep through it.
Humus		formed by a loose layer of leaves that have been shedded.
fertility		Iron combines with oxygen to form rust
loam		is anything in the envirnoment that humans use
soil horizon		dark colored substance that forms as plant and animal remains decay
topsoil		soil that is made up of equal parts of clay, sand and silt.
subsoil		the measure of how well the soil supports plant growth.
litter		a layer of soil that differs in color and texture form the layers above or below it.
Decomposers		the process of ice wedging in rocks that deepen and widen cracks.
sod		farmers disturb the soil and its plant cover as little as possible
natural resource		ruined farmland in western Oklahoma
Dust Bowl		farmers plow their fields along curves of a slope
Soil Conservation		organisms that break down the remains of dead organisms
contour plowing		is the process that breaks down rock through chemical changes
conservation plowing		sol that usually consists of clay and other particles.
crop rotation		is the management of soil to prevent its destruction