soils vocab Flashcards
organic matter
plant and animal residue in the soil in various stages of decompostion.
piping
formation of subsurface tunnels or pipe-like cavitites by water moving through the soil
subsoil
Technically, the B horizon; roughly, the part of the solum below plow depth
ABC soil
A soil having an A B and C horizon
Aggregate soil
many fine particles held in a single mass or cluster. Natural soil aggregates, such as granules, blocks or prisms, are called peds. Clods are aggregates produced by tillage or logging
conservation tillage
a tillage system that does no invert the soil and that leaves a protective amount of crop residue on the surface throughout the year
corrosion
soil-induced electrochemical or chemical action that dissolves or weakens concrete or uncoated steel
excess fines
excess silt and clay in the soil
weathering
All physical and chemical changes produced in rocks or other deposits at or near the earth’s surface by atmospheric agents. These changes result in disintegration and decomposition of the material.
Bottomland
the normal floodplain of a stream, subject to flooding
surface layer
the soil ordinarily moved in tilage, or its equivalent in uncultivated soil, ranging in depth from 4 to 10 inches. Frequently designated as the plow later of the Ap horizon
fast intake
the rapid movement of water into the soil
gravel
Rounded or angular fragments of rock as much as 3 inches in diameter. An individual piece is a pebble
root zone
the part of the soil that can be penatrated by roots
parent material
the unconsolidated organic and mineral material in which soil forms
reaction soil
a measure of acidity or alkalinity of a soil, expressed in pH values
crop residue management
Returning crop residue to the soil, which helps to maintain soil stucture, orgainic matter content, and fertility and helps to control erosion
pH value
a numerical designation of acidity and alkalinity in soil
runoff
the precipitation discharged into stream channels from an area. The water that flows off the surface of the land without sinking into the soil is called surface runoff. Water that enters the soil before reaching surface streams is called groundwater runoff or seepage flow from groundwater
contour stripcropping
Growing crops in strips that follow the contour. Strips of grass or close-growing crops are alternated with strips of clean-tilled crops or summer fallow
topsoil
The upper part of soil, which is the most favorable material for plant growth. It is ordinarily rich in organic matter and is used to topdress roadbanks, lawns, and land affected by mining
Alluvium
material such as sand, silt, or clay, deposited on land by streams
leaching
the removal of souble material from soil or other material by percolating water
subsurface layer
Any surface soil horizon below the surface layer
clay film
a thin coating of oriented clay on the surface of a soil aggregate or lining pores or root channels. Synonyms clay cloating and clay skin
Eluviation
the movement of material in true solution or colloidal suspension from one place to another within the soil. Soil horizons that have lost material through eluviation are eluvial; those that have received material are illuvial
geologic Terrace
an old alluvial plain, ordinarily flat or undulating, bordering a river, lake, or sea
tilth soil
the physical condition of the soil as related to tillage, seedbed preparation, seedling emergence, and root penetration
irrigation
application of water to soils
slope
The inclination of the land surface from the horizontal. Percentage of slop is the vertical distance divided by horizontal distance then multipied by 100.
fallow
cropland left idle in order to restore productivity through accumulation of moisture. Summer fallow is common inregions of limited rainfall where cereal grain is grown.
gully
a miniature valley with steep sides cut by running water and through which water ordinarly runs after rainfall. The distinction between a gully and a rill one of depth. A gully is a obstavcle to farm machinery and is too deep to be obliterated by ordinary tillage; a rill is of lesser depth and can be smoothed over by ordinary tillage
fine textured soil
sandy clay, silty clay, or clay
Bedding planes
fine strata less than 5 millimeters think, in unconsolidated alluvial, colian, lacustrine, or marine sediment
loam
soil material that is 7-27% clay particles, 28% -50% silt particles, and less than 52% sand particles
silt
As a soil separate, individial mineral particles that range in diameter from the upper limit of clay to the lower limit of very fine sand. As a soil textural class, soil that is 80% or more silt and less than 12% clay.
solum
the upper part of a soil profile, above the C horizon, in which the processes of soil formation are active. Th solum in soil consists of the A, E and B horizons.
Terrace
An embankment, or ridge, constructed across sloping soils on the contour or at a slight angle to the contour. The terrace intercepts surface runoff so that water soaks into the soil or flows slowly to a prepared outlet. Generally built for farming.