Chapter 2 Key Terms Flashcards
Erosion
The group of processes whereby earth or rock material is worn away, loosened, or dissolved and removed from any part of the earth’s surface.
Clay
A size term denoting particles, regardless of mineral composition, with diameter less than two microns.
Horizon
A layer of soil, approximately parallel to the surface, having distinct characteristics produced by soil-forming processes.
Internal drainage
The relative degree of downward movement of water in a soil. Also called permeability.
Loam
Soil that consists of less than 52 percent sand, 28 to 50 percent silt, and 7 to 27 percent clay, resulting in a soil texture ideal for gardening.
Organic matter
Matter found in, or produced by, living animals and plants, which contains carbon, hydrogen, oxygen, and often nitrogen and sulfur.
Ped
A unit of soil structure such as an aggregate, crumb, prism, block, or granule, formed by natural processes (in contrast with a clod, which is formed artificially by compression of a wet clay soil).
Permeability
The capacity of soil or rock for transmitting a fluid. Degree of permeability depends upon the size and shape of the pores, the size, and shape of their interconnections, and the extent of the latter.
Porosity
Refers to the extent of voids or openings in the soil that exist between soil particles and soil peds or clods. These pores hold water and air for absorption by plant roots. About half of soil volume which is in a good physical condition for plant growth is pore space.
Sand
In soil science, a group of textural classes in which the particles are finer than gravel but coarser than silt, ranging in size from 2.00 to 0.5 millimeters in diameter. It is the textural class of any soil that contains 85 percent or more of sand and not more than 10 percent of clay.
Silt
A textural class of soils that contains 80 percent or more of silt and less than 12 percent clay.
Soil
The mineral and organic surface of the earth capable of supporting upland plants. It has been (and is being) formed by the active factors of climate and biosphere exerting their influence on passive parent material and topography over neutral time.
Soil profile
A vertical section of a soil. The section, or face of an exposure made by a cut, may exhibit with depth a succession of separate layers although these may not be separated by sharp lines of demarcation.
Soil structure
The arrangement of primary soil particles into compound particles or aggregates that are separated from adjoining aggregates.
Texture
The relative portions of sand, silt, and clay particles in a mass
