Topsoil, the upper mostof the three major soil horizons.
To make air available to soil.
In general, an atmosphere is a blanket of gases surrounding a planet. Unless otherwise identified, however, the term refers to the atmosphere of Earth, which consists of nitrogen (78%), oxygen (21%), argon (0.93%), and other substances that include water vapor, carbon dioxide, ozone, and noble gases such as neon (0.07%).
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.
A combination of all living things on Earth—plants, mammals, birds, reptiles, amphibians, aquatic life, insects, viruses, single-cell organisms, and so on—as well as all formerly living things that have not yet decomposed.
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 earthsystem, 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, but 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.
Loose earth that has been moved into place by a backhoe or some other earthmoving machine, usually as part of a large construction project.
The upper part of Earth's continental crust, or that portion of the solid earth on which human beings live and which provides them with most of their food and natural resources.
Unincorporated, often partially decomposed plant residue that lies at the top of soil and eventually will decay fully to become part of it.
The entirety of Earth's water, excluding water vapor in the atmosphere but including all oceans, lakes, streams, groundwater, snow, and ice.
The removal of soil materials that are in solution, or dissolved inwater.
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 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.
One of the three major types of rock, along with igneous and metamorphic rock. Sedimentary rock typically has its basis in the deposition, compaction, and cementation of rock that has experienced weathering, though it also may be formed as a result of chemical precipitation. Organic sediment also may be a part of sedimentary rock.
The process of erosion, transport, and deposition undergone by sediment.
Layers of soil, parallel to the surface of Earth, that have built up over time. They 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 configuration of Earth's surface, including its relief as well as the position of physical features.
The breakdown of rocks and minerals at or near the surface of Earth due to physical, chemical, or biological processes.
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