Soils Glossary
Acre
A unit of measurement of land. It is equal to the area of land inside a square that is about 209 feet on each side (43,560 square feet).
Bacteria
Microscopic organisms that live on water and on land. They help break down organic materials into simpler nutrients in a process called decay. Bacteria release nutrients to the soil.
Bedrock
A more or less solid layer of rock found on the surface of the land or below the soil.
Complex, Soil
A map unit of two or more kinds of soil in such an intricate pattern or so small in area that it is not practical to map them separately at the selected scale of mapping. The pattern and proportion of the soils are somewhat similar in all areas.
Contour Stripcropping
Growing crops in strips that follow the contour. Strip of grass or close-growing crops are alternated with strip of clean-tilled crops or summer fallow.
Drainage Class
Refers to the frequency and duration of periods of saturation or partial saturation during soil formation, as opposed to altered drainage, which is commonly the result of artificial drainage or irrigation but may be caused by the sudden deepening of channels or the blocking of drainage outlets.
Eluviation
The movement of material in true solution of 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.
Evaporation
Changing a liquid to a gas; for example, when water turns into steam or water vapor.
Fungi (plural of fungus)
A group of non-green plants, such as molds, and mushrooms, that live on dead or dying organic matter. Fungi release nutrients to the soil.
Humus
Highly decomposed plant and animal residue that is a part of soil.
Hydrologic Cycle
The cycle of water movement from the atmosphere to the earth and back again through these steps; evaporation, transpiration, condensation, precipitation, percolation, runoff and storage.
Illuviation
The movement of soil material from one horizon to another in the soil profile. Generally, material is removed from an upper horizon and deposited in a lower horizon.
Leaching
The removal of soluble minerals from soil by the downward movement of water.
Mineral
A naturally occurring inorganic substance with definite chemical and physical properties and a definite crystal structure.
Mottling, Soil
Irregular spots of different colors that vary in number and size. Mottling generally indicates poor aeration and impeded drainage.
Munsell Notation
A designation of color by degrees of three simple variables - hue. value, and chroma. For example, a notation of 10YR 6/4 is a color with hue of 10YR, value of 6, and chroma of 4.
Nematodes
Microscopic, elongated worms that live on other organisms in the soil.
Nutrient
A substance that supplies nourishment for an organism to live. It can be food or chemical depending upon the organism.
Nutrient Exchange
The process by which plant roots exchange an acid for nutrients from the soil.
Organic Matter
Plant and animal material in various stages of decomposition that may be part of the soil.
Parent Material
The earthy mineral and organic-from which soil is formed.
Percolation
The downward movement of water in soil.
Permeability
The quality of soil that allows air or water to move through it.
pH Value
A numerical designation of acidity and alkalinity in soil. (See Reaction, soil)
Pore Spaces
The area of the soil through which water and air move. The space between soil particles.
Precipitation
Rain, snow, and other forms of water that fall to earth.
Reaction, Soil
A measure of acidity or alkalinity of a soil. expressed in pH -values. A soil that tests to pH 7.0 is described as precisely neutral in reaction because it is neither acid or alkaline.
Regolith
The unconsolidated mantle of weathered rock and soil material on the earth's surface; the loose earth material above the solid rock.
Rock Fragments
Rock or mineral fragments having a diameter of 2 millimeters or more; for example, pebbles, cobbles, stones, and boulders.
Root Zone
The part of the soil that can be penetrated by plant roots.
Runoff
Water that flows off land into streams and other waterways.
Sand
As a soil separate, individual rock or mineral fragments from 0.05 millimeter to 2.0 millimeters in diameter. Most sand grains consist of quartz. As a soil textural class, a soil that is 85% or more sand and not more than 10% clay.
Silt
As a soil separate, individual mineral particles that range in diameter from the upper limit of clay (0.002 mm) to the lower limit of very fine sand (0.05 mm). As soil textural class, soil that is 80% or more silt and less than 12% clay.
Soil
A naturally occurring mixture of minerals, organic matter, water and air which has definite structure and composition and forms on the surface of the land.
Soil Color
The color of a sample of soil
Soil Horizon
A layer of soil that is nearly parallel to the land surface and is different from layers above and below.
Soil Mineral
That portion of the soil that is inorganic and neither air nor water.
Soil Survey
The identification, classification, mapping interpretation and explanation of the soil.
Soil Texture
The relative amounts of sand, sift, and clay in a given soil sample.
Subsoil
Technically, the B horizon; roughly, the part of the solum below plow depth.
Substratum
The part f the soil below the solum.
Subsurface Layer
Any surface soil horizon (A, E, AB, or EB) below the surface layer.
Surface Layer
The soil ordinarily moved in tillage, or it equivalent in uncultivated soil, ranging in depth from about 4 to 10 inches (10 to 25 centimeters). Frequently designated as the plow layer, or the Ap horizon.
Topsoil
The upper part of the soil, which is the most favorable material for plant growth. It is ordinarily rich in organic matter and is used to topdress road banks, lawns, and land affected by mining.
Zone of Accumulation
The layer in a soil into which soluble compounds are moved and deposited by water.
Zone of Decomposition
Surface layers in a soil in which organic matter decays.
Zone of Leaching
The layers in a soil from which soluble nutrients are removed by water.
A unit of measurement of land. It is equal to the area of land inside a square that is about 209 feet on each side (43,560 square feet).
Bacteria
Microscopic organisms that live on water and on land. They help break down organic materials into simpler nutrients in a process called decay. Bacteria release nutrients to the soil.
Bedrock
A more or less solid layer of rock found on the surface of the land or below the soil.
Complex, Soil
A map unit of two or more kinds of soil in such an intricate pattern or so small in area that it is not practical to map them separately at the selected scale of mapping. The pattern and proportion of the soils are somewhat similar in all areas.
Contour Stripcropping
Growing crops in strips that follow the contour. Strip of grass or close-growing crops are alternated with strip of clean-tilled crops or summer fallow.
Drainage Class
Refers to the frequency and duration of periods of saturation or partial saturation during soil formation, as opposed to altered drainage, which is commonly the result of artificial drainage or irrigation but may be caused by the sudden deepening of channels or the blocking of drainage outlets.
Eluviation
The movement of material in true solution of 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.
Evaporation
Changing a liquid to a gas; for example, when water turns into steam or water vapor.
Fungi (plural of fungus)
A group of non-green plants, such as molds, and mushrooms, that live on dead or dying organic matter. Fungi release nutrients to the soil.
Humus
Highly decomposed plant and animal residue that is a part of soil.
Hydrologic Cycle
The cycle of water movement from the atmosphere to the earth and back again through these steps; evaporation, transpiration, condensation, precipitation, percolation, runoff and storage.
Illuviation
The movement of soil material from one horizon to another in the soil profile. Generally, material is removed from an upper horizon and deposited in a lower horizon.
Leaching
The removal of soluble minerals from soil by the downward movement of water.
Mineral
A naturally occurring inorganic substance with definite chemical and physical properties and a definite crystal structure.
Mottling, Soil
Irregular spots of different colors that vary in number and size. Mottling generally indicates poor aeration and impeded drainage.
Munsell Notation
A designation of color by degrees of three simple variables - hue. value, and chroma. For example, a notation of 10YR 6/4 is a color with hue of 10YR, value of 6, and chroma of 4.
Nematodes
Microscopic, elongated worms that live on other organisms in the soil.
Nutrient
A substance that supplies nourishment for an organism to live. It can be food or chemical depending upon the organism.
Nutrient Exchange
The process by which plant roots exchange an acid for nutrients from the soil.
Organic Matter
Plant and animal material in various stages of decomposition that may be part of the soil.
Parent Material
The earthy mineral and organic-from which soil is formed.
Percolation
The downward movement of water in soil.
Permeability
The quality of soil that allows air or water to move through it.
pH Value
A numerical designation of acidity and alkalinity in soil. (See Reaction, soil)
Pore Spaces
The area of the soil through which water and air move. The space between soil particles.
Precipitation
Rain, snow, and other forms of water that fall to earth.
Reaction, Soil
A measure of acidity or alkalinity of a soil. expressed in pH -values. A soil that tests to pH 7.0 is described as precisely neutral in reaction because it is neither acid or alkaline.
Regolith
The unconsolidated mantle of weathered rock and soil material on the earth's surface; the loose earth material above the solid rock.
Rock Fragments
Rock or mineral fragments having a diameter of 2 millimeters or more; for example, pebbles, cobbles, stones, and boulders.
Root Zone
The part of the soil that can be penetrated by plant roots.
Runoff
Water that flows off land into streams and other waterways.
Sand
As a soil separate, individual rock or mineral fragments from 0.05 millimeter to 2.0 millimeters in diameter. Most sand grains consist of quartz. As a soil textural class, a soil that is 85% or more sand and not more than 10% clay.
Silt
As a soil separate, individual mineral particles that range in diameter from the upper limit of clay (0.002 mm) to the lower limit of very fine sand (0.05 mm). As soil textural class, soil that is 80% or more silt and less than 12% clay.
Soil
A naturally occurring mixture of minerals, organic matter, water and air which has definite structure and composition and forms on the surface of the land.
Soil Color
The color of a sample of soil
Soil Horizon
A layer of soil that is nearly parallel to the land surface and is different from layers above and below.
Soil Mineral
That portion of the soil that is inorganic and neither air nor water.
Soil Survey
The identification, classification, mapping interpretation and explanation of the soil.
Soil Texture
The relative amounts of sand, sift, and clay in a given soil sample.
Subsoil
Technically, the B horizon; roughly, the part of the solum below plow depth.
Substratum
The part f the soil below the solum.
Subsurface Layer
Any surface soil horizon (A, E, AB, or EB) below the surface layer.
Surface Layer
The soil ordinarily moved in tillage, or it equivalent in uncultivated soil, ranging in depth from about 4 to 10 inches (10 to 25 centimeters). Frequently designated as the plow layer, or the Ap horizon.
Topsoil
The upper part of the soil, which is the most favorable material for plant growth. It is ordinarily rich in organic matter and is used to topdress road banks, lawns, and land affected by mining.
Zone of Accumulation
The layer in a soil into which soluble compounds are moved and deposited by water.
Zone of Decomposition
Surface layers in a soil in which organic matter decays.
Zone of Leaching
The layers in a soil from which soluble nutrients are removed by water.
