Topsoil, the upper mostof the three major soil horizons.
To make air available to soil.
Subsoil, beneath topsoil and above regolith.
The solid rock that lies below the C horizon, the deepest layer of soil.
The changes that particular elements undergo as they pass back and forth through the various earth systems and particularly between living and nonliving matter. The elements involved in biogeochemical cycles are hydrogen, oxygen, carbon, nitrogen, phosphorus, and sulfur.
Regolith, which lies between subsoil and bedrock and constitutes the bottommost of the soil horizons.
Organisms that obtain their energy from the chemical breakdown of dead organisms as well as from animal and plant waste products. The principal forms of decomposer are bacteria and fungi.
A chemical reaction in which a compound is broken down into simpler compounds or into its constituent elements. In the earth system, this often is achieved through the help of detritivores and decomposers.
Organisms that feed on waste matter, breaking organic material down into inorganic substances that then can become available to the biosphere in the form of nutrients for plants. Their function is similar to that of decomposers;however, unlike decomposers—which tend to be bacteria or fungi—detritivores are relatively complex organisms, such as earthworms or maggots.
A community of interdependent organisms along with the inorganic components of their environment.
The movement of soil and rock due to forces produced by water, wind, glaciers, gravity, and other influences. In most cases, a fluid medium, such as air or water, is involved.
A state of heightened biological productivity in a body of water, which is typically detrimental to the ecosystem in which it takes place. Eutrophication can be caused by an excess of nitrogen or phosphorus in the form of nitrates and phosphates, respectively.
Unincorporated, often partially decomposed plant residue that lies at the top of soil and eventually will decay fully to become part of it.
A notable topographicalfeature, such as a mountain, plateau, or valley.
The removal of soil materials that are in solution, or dissolved inwater.
The transfer of earth material down slopes by processes that include creep, slump, slide, flow, and fall. Also known as mass movement.
A naturally occurring, typically inorganic substance with a specific chemical composition and a crystalline structure.
At one time chemists used the term organic only in reference to living things. Now the word is applied to most compounds containing carbon, with the exception of carbonates (which are minerals) and oxides, such as carbon dioxide.
Mineral fragments removed from rocks by means of weathering. Along with organic deposits, these fragments form the basis for soil.
A general term describing a layer of weathered material that rests atopbedrock.
Material deposited at or near Earth's surface from a number of sources, most notably preexisting rock. There are three types of sediment: rocks, or clastic sediment; mineral deposits, or chemical sediment; and organic sediment, composed primarily of organic material.
The process of erosion, transport, and deposition undergone by sediment.
The application of principles for maintaining the productivity and health of agricultural land by control of wind-and water-induced soil erosion. The term also may be applied more broadly to encompass the maintenance and protection of non agricultural soils.
Layers of soil, parallel to the surface of the earth, which have built up over time. These layers are distinguished from one another by color, consistency, and composition.
A cross-section combining all or most of the soil horizons that lie between Earth's surface and the bedrock below it.
The breakdown of rocks and minerals at or near the surface of Earth due to physical, chemical, or biological processes.
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