Soil Flashcards
The top layer of earth’s surface, consisting of disintegrated rock and decayed organic matter suitable for the growth of plant life.
Soil
The fertile surface layer of soil, as distinct from the subsoil.
Topsoil
The bed or layer of earth immediately beneath the surface soil.
Subsoil
Perennially frozen subsoil in arctic or subarctic regions.
Permafrost, pergelisol
The unbroken, solid rock that underlies all unconsolidated material on the earth’s surface, such as soil, clay, sand or rock fragments.
Bedrock
Soil containing a large amount of organic matter, usually very compressible and having poor load-sustaining properties.
Organic Soil
A diagram of a vertical section of soil from the ground surface to the underlying material, showing a succession of horizons developed by weathering, deposition, or both.
Soil Profile
Any of a series of relatively distinct layers of soil or its underlying material found in a vertical section of land.
Horizon
A single bed or layer of sedimentary earth or rock having the same composition throughout, lying between beds of another kind.
Stratum
A process for determining the particle-size distribution in an aggregate, soil or sediment.
Soil Analysis
A numerical classification of soil by texture, used by the US Department of Agriculture. 1 - Gravel
2 - Sand
3 - Clay
4 - Loam
5 - Loam with some sand
6 - silt-loam
7 - Clay-loam
Soil Class
A large, naturally rounded rock, lying on the surface of the ground or partially embedded in it.
Boulded
A naturally rounded stone, smaller than a boulder and larger than a pebble, used for rough paving, walls, and foundations.
Cobble, Cobblestone
Small pebbles and stones, or a mixture of these with sand, formed either naturally or by crushing rock, esp such material that will pass a 3in sieve and be ratained on a no.4 (4.8mm) sieve.
Gravel
Gravel having one or more fractured faces produced by mechanical crushing.
Crushed Gravel
Stone having well-defined edges produced by the mechanical crushing of rocks or boulders.
Crushed Stone, Crushed Rock
A small-diameter, natural gravel, usually 1/4” to 3/8” (6.4 to 9.5mm) in size, screened to specification.
Pea Gravel
A small, rounded stone, especially one worn smooth by the action of water.
Pebble
A loose, granular material resulting from the disintegration of rocks, consisting of grains smaller than gravel but coarser than silt.
Sand
A well-graded, naturally occurring sand often used as a base or subbase material, having about 10% clay or just enough to make the mixture bind tightly when compacted.
Sand Clay
Loose sedimentary material consisting of fine mineral particles between 0.002mm and 0.05mm in diameter.
Silt
A natural, earthy material that is plastic when moist but hard when fired and is used for making brick, tile, and pottery, composed mainly of fine particles of hydrous aluminum silicates less than 0.002mm in diameter.
Clay
Soil containing 27% to 40% clay and 20% to 45% sand.
Clay Loam
A clay formed by the decomposition of volcanic ash, having the ability to absorb large amounts of water and expand to several times its natural volume.
Bentonite
