Glossary

This section identifies words, terms, or phrases that are used within the National Handbook of Conservation Practices. These terms best represent the technical information presented in the standards. All significant terms that may have a meaning more specialized or more restrictive than the common dictionary meaning are defined here for clarification for the user of the standards and to best represent the intended use of terms within the NRCS standards.

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Glossary of Landform and Geologic Terms (PDF; 5,259 KB)

 

Absorption	The physical integration of a liquid into the pore spaces of a solid, such as water being absorbed into a sponge.
Aeration	A process causing intimate contact between air and a liquid by one or more of the following methods: (a) spraying the liquid in the air, (b) bubbling air through the liquid, and (c) agitating the liquid to promote absorption of oxygen through the air liquid interface.
Aeration, soil	The exchange of air in soil with air from the atmosphere. The air in a well-aerated soil is similar to that in the atmosphere; the air in a poorly aerated soil is considerable higher in carbon dioxide and lower in oxygen.
Aerobic	Having or occurring in the presence of free oxygen.
Agricultural waste management system	A combination of conservation practices to collect, transport, store or treat, and apply animal waste, and the management that, when applied, will protect the resource base.
Agricultural wastes	Wastes normally associated with the production and processing of food and fiber on farms, feedlots, ranches, ranges, and forests which may include animal manure, crop residues, and dead animals; also, agricultural chemicals, fertilizers, and pesticides which may find their way into surface and subsurface water.
Alluvium	Sediment deposited by streams and rivers.
Ammonia volatilization	The loss of ammonium to the atmosphere
Ammonium	Anion (NH4+) derived from ammonia (NH3)
Anaerobic	The absence of molecular oxygen, or growing in the absence of oxygen.
Anaerobic digester	A heated, airtight apparatus that facilitates anaerobic digestion.
Anaerobic digestion	Conversion of organic matter in the absence of oxygen under controlled conditions to such gases as methane and carbon dioxide.
Anaerobic lagoon	A structure o treat animal waste by predominantly anaerobic biological action using anaerobic or facultative organisms, in the absence of air, for the purpose of reducing the organic matter in wastes.
Artesian well	A well deriving its water from a confined aquifer in which the water level stands above the ground surface; synonymous with flowing well.
Available forage	That portion of the forage production that is accessible for use by a specified kind or class of grazing animal. It is the consumable forage stated in digestible dry matter per land unit area that can be removed by grazing livestock without damage to the forage plants.
Available nitrogen	Form of nitrogen that is immediately available for plant growth (NO3-) or (NH4+)
Available phosphorus	Forms of phosphorus that can be immediately used for plant growth.
Available water capacity (available moisture capacity)	The capacity of soils to hold water available for use by most plants. It is commonly defined as the difference between the amount of soil water at field capacity and the amount at wilting point. It is commonly expressed as inches of water per inch of soil. The capacity, in inches, in a 60-inch profile or to a limiting layer is expressed as inches. 12 inches
Base flow	Water that, having infiltrated the soil surface, percolates to the ground water table and moves laterally to reappear as surface runoff.
Bedrock	The solid rock that underlies the soil and other unconsolidated material or that is exposed at the surface
Benchmark	(1) A permanent reference point.(2) In range inventory, it is used as a point where changes in vegetation through time are measured.(3) In soils, it is used to designate a major soil series that is representative of similar soils.(4) In economics, data that are used as a base for comparative purposes with similar data.(5) A surveyor’s mark made on a permanent landmark that has known position and altitude.
Best Management Practice(s) (BMP)	A practice or combination of practices found to be the most effective, practicable (including economic and institutional considerations) means of preventing or reducing the amount of pollution generated by non-point sources to a level compatible with water quality goals.
Biological wastewater Treatment	Forms of wastewater treatment in which bacterial or biochemical action is intensified to stabilize or oxidize the unstable organic matter present. Oxidation ditches, aerated lagoons, anaerobic lagoons and anaerobic digesters are examples.
Biomass	The total amount of living material, plants and animals, above and below ground in a particular area.
Boulders	Rock fragments larger than 2 feet (60 cm) in diameter
Broadcast seeding	Process of scattering seed on the surface of the soil prior to natural or artificial means of covering the seed with soil.
Cabling	The use of a large cable pulled between two large tractors (usually crawler tractors) to pull sown or uproot brush.
Carbonate	Sediment formed by the organic or inorganic precipitation from aqueous solution of carbonates of calcium, magnesium, or iron.
Certified seed	Seed produced from foundation or registered seed that is available for consumer use. It carries a tag signifying it is high quality seed.
Chiseling	Breaking or loosening the soil, without inversion, with a chisel cultivator or chisel plow. A practice used for cropland, grassland or pasture renovation.
Clay (size)	The mineral soil particles less than 0.002 millimeters in diameter.
Clay (texture class)	As a soil textural class, soil material that is 40 percent or more clay, less than 45 percent sand, and less than 40 percent silt.
Coarse-grained soil  (textured class)	In the USDA Soil Classification System, a texture group consisting of the sands and loamy sands texture classes.
Coarse-grained soil (engineering)	The minus 3-inch (75-mm) fraction of soil having a gradation such that more than 50 percent by dry weight is retained on the No. 200 (75-um) sieve.
Coliform bacteria	A group of bacteria predominantly inhabiting the intestines of man or animal, but also found in soil. It includes all aerobic and facultative anaerobic, gram-negative, non-spore-forming bacilli that ferment lactose with production of gas. This group of “total” coliforms includes Escherichia coli, which is considered the
Community (Plant)	An assemblage of plants occurring together at any point in time, while denoting no particular ecological status. A unit of vegetation.
Composting	A process of aerobic biological decomposition characterized by elevated temperatures that, when complete, results in a material that is relatively inert, safe, and makes an excellent soil conditioner.
Cone of depression	A depression in the ground water table or potentiometer surface that has the shape of an inverted cone and develops around a well from which water is being withdrawn. It defines the area of influence of a well.
Confined aquifer	A formation in which the ground water is isolated from the atmosphere at the point of discharge by impermeable geologic formations. Confined ground water is generally subject to pressure greater than atmospheric.
Conservation cropping sequence	An adapted sequence of crops designed to provide adequate organic residue for maintenance or improvement of soil tilth and for other conservation purposes.
Conservation plan	A record of the client’s decisions and supporting information, for treatment of a unit of land or water as a result of the planning process, that meets FOTG quality criteria for each natural resource (soil, water, air, plants, and animals) and takes into account economic and social considerations. The plan describes the schedule of operations and activities needed to solve identified natural resource problems, and take advantage of opportunities, at a resource management system level. The needs of the client, the resources, and Federal, State and local requirements will be met.
Conservation practice	A specific structural, managerial, or cultural treatment of natural resources commonly used to meet a specific need in planning and carrying out soil and water conservation programs.
Contamination	The degradation of water quality as result of natural processes and/or the activities of people. No specific limits are established because the degree of permissible contamination depends upon the intended end use or uses of water.
Conventional tillage	Those primary and secondary tillage operations that are considered standard for the specific location and crop.
Cost effectiveness	A term used to economically compare agricultural no point source control alternatives. It is generally expressed as dollars per unit pollutant load reduction.
Cover crop	A close-growing crop, whose main purpose is to protect and improve the soil and use excess nutrients or soil moisture during the absence of the regular crop, or in the no vegetated areas of orchards and vineyards.
Critical area	An area to be treated with special consideration because of inherent site factors, size, location, condition, values, or significant potential conflicts among uses.
Crop residue	The portion of a crop remaining after harvest of seed or other primary plant parts. It may be managed for grazing and/or ground cover and to replenish soil organic matter levels.
Crop rotation	A planned sequence of crops.
Cropland	Land used primarily for the production of cultivated crops.
Deciduous (plant)	A plant whose parts, particularly leaves, are shed at regular intervals or at a given stage of development.
Decision maker	An individual, group, unit of government, or other entity that has the authority by ownership, position, office, delegation, or otherwise to decide on a course of action.
Deep percolation	The downward movement of water through the soil and below the root zone.
Denitrificaiton	The chemical or biological reduction of nitrate or nitrite to gaseous nitrogen, either as molecular nitrogen (N2) or as an oxide of nitrogen (N20).
Detention pond	A water impoundment made by constructing a dam or an embankment, or by excavating a pit or dugout usually to provide temporary storage of runoff.
Direct runoff	Both surface flow and the interflow component of subsurface flow
Dissolved oxygen (DO)	The molecular oxygen dissolved in water, wastewater, or other liquid; generally expressed in milligrams per liter, parts per million, or percent of saturation.
Diversity	A measure of the number of species and their relative abundance in a community.
Dormant	(1) A living plant that is not actively growing aerial shoots.(2) A pesticide application made on crop plants that are not actively growing.
Dormant seeding	Planting seed during the fall when seeds will not germinate until next spring.
Drill seeding	Planting seed directly into the soil with a drill in rows, usually 6 to 24 inches apart.
Drip line	The area under the outermost branches of a tree or shrub.
Drouth (drought)	(1) A prolonged chronic shortage of water. (2) A period with below normal precipitation during which the soil water content is reduced such an extent that plants suffer from lack of water; frequently associated with excessively high temperatures and winds during spring, summer, and fall in many parts of the world.
Effluent	The liquid discharge of a waste treatment process.
Erosion	The wearing away of the land surface by water, wind, ice or other geologic agents and by such processes such as gravitational creep.
Erosion (accelerated)	Erosion occurring more rapidly than geologic erosion, mainly as a result of the activities of man or other animals or of a catastrophe in nature, for example, fire that exposes the surface.
Eutrophicution	A natural or artificial process of nutrient enrichment whereby a water body becomes abundant in plant nutrients and low in oxygen content.
Evapotranspiration	The loss of water from an area by evaporation from the soil or snow cover and transpiration by plants.
Exotic	An organism or species that is not native to the region in which it is found.
Fault	A fracture or a zone of fractures along which there has been displacement of the sides relative to one another parallel to the fracture.
Fertilizer value	An estimate of the value of commercial fertilizer elements (N, P, K) that can be replaced by manure or organic waste material. Usually expressed as dollars per ton of manure or quantity of nutrients per ton of manure.
Field moisture capacity	The moisture content of a soil, expressed as a percentage of the oven-dry weight, after the gravitational, or free, water has drained away.
Fine textured soil	Sandy clay, silty clay, and clay.
Flooding	The temporary covering of the soil surface by water that flows over it from any source, such as a stream, irrigation canal, tidal action, or runoff from adjacent or surrounding slopes.
Flushing system	A system that collects and transports or moves waste material with the use of water, such as in washing of pens and flushing confinement livestock facilities.
Fluvial	Pertaining to or produced by the action of a stream or river.
Forage	All browse and herbage that is available and acceptable to grazing animals or that may be harvested for feeding purposes. Act of consuming forage. Syn. graze.
Ford	A constructed or natural stream crossing for equipment, humans, or animals at a point where water is shallow, footing is firm, and banks are low or inclined for easy approach and exit. The bottom of the channel and approaches are either naturally or artificially paved to facilitate ease of crossing and to reduce muddying of the water.
Geographic Information System (GIS)	A spatial type of information management system that provides for the entry, storage, manipulation, retrieval and display of spatially oriented data.
Global Positioning System (GPS)	A computer based receiver system that uses satellite transmissions to determine precise latitude and longitude readings at any location in a field. This system is used to map crop yield, soil fertility, weed infestations, soil type, and other yield influencing differences. It then forms the basis for variable rate applications of fertilizer and pesticides. Application equipment is guided by a georeferenced program to deliver different application rates as it traverses back and forth across a field.
Grassed infiltration area	An area with vegetative cover where runoff water infiltrates into the soil
Green manure	Any crop or plant grown and not harvested that is used to improve the soil’s organic matter content and structure. It may or may not be incorporated by tillage.
Ground water	Subsurface water that is in the zone of saturation. The top surface of the ground water is the water table. Source of water for wells, seepage, and springs.
Ground water table	The surface between the zone of saturation and the zone of aeration. The surface of an unconfined aquifer.
Guide	A detailed summary of information or series of options that does not recommend a specific course of actions.
Head	Energy contained in a water mass; expressed in elevation (feet) or pressure (pounds per square feet).
Head loss	That part of head energy, which is lost because of friction as water flows.
Herbaceous	Vegetative growth with little or no woody component. Non-woody vegetation, such as graminoids and forbs.
Herbicide	A chemical used to kill or inhibit the growth of plants.
Horizon, soil	A layer of soil, approximately parallel to the surface, having distinct characteristics produced during soil-forming processes.
Hydraulic conductivity	The rate of flow of water in gallons per day through a cross section of one square foot under a unit hydraulic gradient, at the prevailing temperature (gpd/ft2). In the SI system, the units are m3/day/m2 or m/day.
Hydraulic gradient	The rate of change in total head per unit of distance of flow in a given direction.
Hydrologic condition	Description of the moisture present in a soil by amount, location, and configuration.
Hydrologic soil groups	A classification system used by the Natural Resources Conservation Service to group soils according to their runoff producing characteristics. The chief consideration is the inherent capacity of soil bare of vegetation to permit infiltration. The slope and kind of plant cover are not considered, but are separate factors in predicting runoff. Soils are assigned to four groups. In-group A is soils having a high infiltration rate when thoroughly wet and having a low runoff potential. They are mainly deep, well drained, and sandy or gravelly. In-group D, at the other extreme, are soils having a very slow infiltration rate and thus a high runoff potential. They have a clay pan or clay layer at or near the surface, have a permanent high water table, or are shallow over nearly impervious bedrock or other material.
Indicator species	(1) Species that indicate the presence of certain environmental condition, range condition, previous treatment, or soil type. (2) One or more plant species selected to indicate a certain level of grazing use.
In filtration rate	The rate, at which water penetrates the surface of the soil at any given instant, usually expressed in inches per hour. The rate can be limited by the infiltration capacity of the soil or the rate at which water is applied at the surface.
Karst topography	A type of topography that is formed in limestone, gypsum, and other similar type rock by dissolution and are characterized by sinkholes, caves, and rapid underground water movement.
Lagoon	A shallow impoundment made by excavation or earthfill for the purpose of waste treatment.
Landscape	The environment, both natural and built, that surrounds us.
Landscape quality	A composite of those landscape conditions and perceived values that provide diverse and pleasant surroundings for human use and appreciation. Recognized components of landscape quality include visual resource, landscape use, viewscape, and visibility.
Leaching	(1) The removal of soluble constituents, such as nitrates or chlorides, from soils or other material by the movement of water.(2) The removal of salts and alkali from soils by irrigation combined with drainage.(3) The removal of a liquid through a non-watertight artificial structure, conduit, or porous material by downward or lateral drainage, or both, into the surrounding permeable soil.
Limestone	A sedimentary rock consisting chiefly of calcium carbonate.
Limiting nutrient	Nutrient that restricts plant growth.
Liquid manure	A mixture of water and manure that behaves more like a liquid than solid, generally less than 5 percent solids.
Livestock waste	A term sometimes applied to manure that may also contain bedding, spilled feed, eater, or soil. It also includes wastes not particularly associated with manure, such as milking center or washing wastes, and milk, hair, feathers, or other debris.
Manure	The fecal and urinary excretions of livestock and poultry.
Mechanical solids separation	The process of separating suspended solids from a liquid-carrying medium by trapping the particles on a mechanical
Microclimate	Climate as experienced at the scale of a particular site. Includes such elements as solar orientation, wind direction, temperature, and precipitation.
Monitoring	Systematic collection of data on a routine basis and the analysis of these data for an understanding of the changes that may occur in the sampled environment.
Mulch	Any substance that is spread on the soil surface to decrease the effects of raindrop impact, runoff, and other adverse conditions and to retard evaporation.
Municipal waste	Solid and liquid fractions of wastes produced by a municipality. Municipal wastes may be treated or untreated and may be either used or disposed of.
Native species	A species, which is a part of the original fauna or flora of the area in question.
Nitrogen	A chemical element commonly used in fertilizer as a nutrient, which is also a component of animal wastes. As one of the major nutrients required for plant growth, nitrogen can promote algae blooms that cause water body eutrophication if it runs off or leaches out of the surface soil. Nitrogen is immediately usable for plant growth in available forms (NO3-) or (NH4+)
Nitrogen cycle	The succession of biochemical reactions that nitrogen undergoes as it is converted to organic or available nitrogen from the elemental form. Organic nitrogen in waste is oxidized by bacteria into ammonia (NH3).If oxygen is present, ammonia is bacterially oxidized first into nitrite (NO2-) and then into nitrate (NO3-).If oxygen is not present, nitrite and nitrate are bacterially reduced to nitrogen gas, completing the cycle.
No point source (NPS)	Entry of effluent into a water body in a diffuse manner so there is no definite point of entry.
No-till	A planting procedure that requires no tillage except that done by a coulter or disk opener in the immediate area of the crop row.
Noxious weed	An unwanted plant specified by Federal or State laws as being especially undesirable, troublesome, and difficult to control. It grows and spreads in places where it interferes with the growth and production of the desired crop.
Nutrients	Elements required for plant or animal growth, including the macronutrients (nitrogen, phosphorus, and potassium), which are the major nutrients required and micronutrients, which include a number of other elements that are essential but needed in lesser amounts.
Organic matter	The organic fraction of the soil exclusive of undecayed plant and animal residue.
Overgrazing	Grazing that exceeds the recovery capacity of the individual species or the plant community.
Pasture	(1) Grazing lands comprised of introduced or domesticated native forage species that are used primarily for the production of livestock. They receive periodic renovation and/or cultural treatments such as tillage, fertilization, mowing, weed control, and may be irrigated. They are not in rotation with crops.(2) A grazing area enclosed and separated from other areas by fencing or other barriers. The management unit for grazing land.(3) Forage plants used as food for grazing animals.(4) Any area devoted to the production of forage, native or introduced, and harvested by grazing.
Percolation	The downward movement of water through soil.
Percolation rate	The rate of movement of water under hydrostatic pressure down through the interstices of rock, soil, or filtering media except movement through large openings, such as caves.
Permanent wilting point	The moisture content of soil, on an oven-dry basis, at which a plant (specifically a sunflower) wilts so much that it does not recover when
Permeability	The quality of the soil that enables water to move downward through the profile.  Permeability is measured as the number of inches per hour that water moves downward through the saturated soil.  Terms describing permeability are: Very slow less than 0.06 inches/hr Slow 0.06 to 0.2 inches/hr Moderately slow 0.2 to 0.6 inches/hr Moderate 0.6 to 2.0 inches/hr Moderately rapid 2.0 to 6.0 inches/hr Rapid 6.0 to 20 inches/hr
Pesticide	Any chemical agent such as herbicide, fungicide, or insecticide, used for control of specific organisms.
pH	The negative logarithm of the hydrogen ion concentration.  The pH scale ranges from zero to 14.Values below 7 are considered acidic and those above
Phosphate	Phosphate ions exist in water as H2PO4 – or HPO4-2Otherwise phosphate is an ester or salt of phosphoric acid, such as calcium phosphate rock.
Phosphorus	One of the primary nutrients required for the growth of plants.  Phosphorus is often the limiting nutrient for the growth of aquatic plants and algae.
Point source	The release of a contaminant or pollutant, often in concentrated form, from a conveyance system, such as a pipe, into a water body.
Pollution/polluted	The presence in a body of water (or soil or air) of a substance (contaminant) in such quantities that it impairs the body’s usefulness or renders it offensive to the senses of sight, taste, or smell.  In general, a public health hazard may be created, but in some instances only economic or aesthetics are involved, such as when foul odors pollute the air.
Pond	A water impoundment made by constructing a dam or an embankment, or by excavating a pit or dugout usually to supply drinking water for livestock and or wildlife.
Ponding	Standing water on soils in closed depressions.  Unless the soils are artificially drained, the water can be removed only by percolation or evapotranspiration.
Porous dam	A runoff control structure that reduces the rate of runoff so that solids settle out in the settling terrace or basin.  The structure may be constructed of rock, expanded metal, or timber arranged with narrow slots.
Potassium	One of the primary nutrients required for the growth of plants.
Profile, soil	A vertical section of the soil extending through all its horizons and into the parent material.
Pumping test	A test that is conducted to determine aquifer or well characteristics
Rangeland	Land on which the historic climax plant community is predominantly grasses, grasslike plants, forbs, or shrubs.  Includes lands revegetated naturally or artificially when routine management of that vegetation is accomplished mainly through manipulation of grazing.  Rangeland includes natural grasslands, savannas, shrublands, most deserts, tundra, alpine communities, coastal marshes, and wet meadows.
Reclamation	Restoration of a site or resource to a desired condition to achieve management or stated goals.
Reduced tillage	A management practices whereby the use of secondary tillage operations is significantly reduced.
Resource base	The combination of soil, air, water, plants, and animals that makes up the natural environment
Resource Management System (RMS)	A combination of conservation practices and resource management, for the treatment of all identified resource concerns for soil, water, air, plants, and animals, that meets or exceeds the quality criteria in the FOTG for resource sustainability.
Ridge planting	The practice of growing a row crop on the ridges between the furrows.
Riparian	Area, zone, and/or habitat adjacent to streams, lakes, or other natural free water, which have a predominant influence on associated vegetation or biotic communities.
Root zone	The part of the soil that can be penetrated by plant roots.
Ruminant	Even-toed, hoofed mammals such as cow, goat, or sheep, having a 4-chamber stomach; and chewing a cud consisting of regurgitated, partially digested food, i.e., ruminantia
Runoff	The part of precipitation or irrigation water that appears in surface streams or water bodies; expressed as volume (acre-inches) or rate of flow (gallons per minute, cubic feet per second).
Salt	A compound made up of the positive ion of a base and the negative ion of an acid.
Salvage value	The value remaining in a piece of equipment or other asset at the end of its intended useful life.
Sampling	Collection of a small part of an entity and drawing conclusions about the whole. In water quality considerations, sampling consists of collecting a representative part of a water body for testing from which conclusions can be drawn about the water body as a whole.
Sediment delivery	Sediment arriving at a specific location.
Sediment yield	Quantity of sediment leaving a specified land area.
Seed inoculation	Treatment of legume seed with rhizobium bacteria before planting to enhance subsequent nitrogen fixation.
Seep	Wet areas, normally not flowing, often created when the elevation of the lateral flow of underground water intersects ground level, as on a hillslope.Occasionally seeps occur from water arising from water arising from an underground source.
Sewage sludge	Settled sewage solids combined with varying amounts of water and dissolved materials that are removed from sewage by screening, sedimentation, chemical precipitation, or bacterial digestion.
Sheet erosion	Soil erosion occurring from a thin, relatively uniform layer of soil particles on the soil surface. Also called inter-rill erosion.
Site design	A careful search among physical elements to plan for human and animal occupation and utilization of a site so that comfort, profitability, and usefulness are maximized and harmful stress is reduced.
Slope	The inclination of the land surface from the horizontal. Percentage of slope is the vertical distance divided by horizontal distance, then multiplied by 100.Thus, a slope of 20 percent is a drop of 20 feet in 100 feet of horizontal distance.
Sodicity	The degree to which a soil is affected by exchangeable sodium. Sodicity is expressed as a sodium adsorption ratio (SAR) of a saturation extract.
Soil	A natural, three-dimensional body at the Earth’s surface.  It is capable of supporting plants and has properties resulting from the integrated effect of climate and living matter acting on earthy parent material, as conditioned by relief over time.
Soil amendment	Any material, such as lime, gypsum, sawdust, or synthetic conditioner that is worked into the soil to make it more amenable to plant growth. Amendments may contain important fertilizer elements, but the term commonly refers to added materials other than fertilizer.
Soil and water conservation practices	The manipulation of such variables as crops, rotation, tillage, management, and structures to reduce the loss of soil and to conserve water.
Soil organic matter	The organic fraction of the soil that includes plant and animal residue at various stages of decomposition, exclusive of undecayed plant and animal residue. Often used synonymously with humus.
Soil reaction	Numerical expression in pH units of the relative acidity or alkalinity of a soil. The range in soil pH is 0 to 14.0A pH of 7.0 is neutral.
Soil test	A chemical and physical analysis of a soil used to estimate its nutrient supplying power. It must use chemical extraction techniques appropriate for the elements being extracted and the soil being examined. For the results to be interpreted properly, the test procedures must also be calibrated against nutrient rate experiments in the field and in the greenhouse.
Solid manure storage	A storage unit in which accumulations of bedded manure or solid manure is stacked before subsequent handling and field spreading. The liquid parts, including urine and precipitation, may or may not be drained from the unit.
Spatial	The occupied space relationship between a soil and soil map unit to the landscape or geomorphic surface on which the soil or map unit is located.
Specification	An explicit set of requirements to be satisfied by a material, product, system, or service, such as construction. It also identifies the methods for determining whether each of the requirements is satisfied.
Standard	A statement of acceptable quality or technical excellence in terms of both form and function (performance), usually expressed in terms of limits, i.e. minimum or maximum.
State Technical Committee	A technical committee in each State to assist in the technical considerations and to develop the technical guidelines necessary to implement the conservation provisions of the Food Security Act of 1985, as amended. The State Technical Committee is composed of representatives from Federal Agencies, Private Interest members, State Departments, Agencies and Other outside Groups.
State Technical Guide Committee (STGC)	The STGC is a committee of principal NRCS staff responsible for the approval and distribution of State-developed, State-supplemented, or field office-supplemented FOTG materials. The STGC is also responsible for quality assurance activities to ensure the completeness and currency of FOTG materials
Stock pond	A water impoundment made by constructing a dam or by excavating a dugout or both, to provide water for livestock and/or wildlife.
Stream classification	The identification of specific channel categories, types, or characteristics so that consistent descriptions and assessments of the conditions and potential for the stream can be developed.
Structural controls	Candidate measures that require capital investment, construction activities, and consequently, certain economic risks.
Subsoil	Technically, the B-horizon; roughly, the part of the solum below plow depth.
Subsurface runoff	Water that infiltrates the soil and then moves laterally below the surface; includes baseflow and interflow.
Succession	The progressive replacement of plant communities on an ecological site that leads to the climax plant community.
Suitability	(1) The adaptability of an area to grazing by livestock or wildlife.(2) The adaptability of a particular plant or animal species to a given area.
Surface layer	The soil ordinarily moved in tillage, or its 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 “A horizon." Some water quality models refer to surface layer as the first few centimeters of soil.
Suspended solids	(1) Undissolved solids that are in water, wastewater, or other liquids, and are largely removable by filtering or centrifuging.(2) The quantity of material filtered from wastewater in a laboratory test, as prescribed in APHA Standard Methods for the Examination of Water and Wastewater or similar reference.
Texture, soil	The relative proportions of sand, silt, and clay particles in a mass of soil.
Tilth, soil	The physical condition of the soil as related to tillage, seedbed preparation, seedling emergence, and root penetration.
Total solids	The total amount of solids in a waste, both in solution and suspension.
Toxicity	Degree of harmful affects an element or compound may have on a living organism, plant, or animal. Excessive amount of toxic substances, such as sodium or sulfur that severely hinder establishment of vegetation or severely restrict plant growth.
Understory	Plants growing beneath the canopy of other plants. Usually refers to grasses, forbs, and low shrubs under a tree or shrub canopy.
Universal Soil Loss Equation (USLE)	An empirical equation estimating the amount of soil loss. Used for the evaluation of a resource management system for water erosion control. The revised equation is called RUSLE.
Vadose zone	The zone containing water under less pressure than that of the atmosphere, including soil water, intermediate vadose water, and capillary water. This zone is limited above by the land surface and below by the surface of the zone of saturation, that is, the water table.
Vector	A bearer or carrier such as an organism (often an insect) that carries and transmits disease-causing microorganisms.
Vegetative practices	Practices that are directly concerned with the use and growth of plants. These include such practices as prescribed grazing and livestock exclusion.
View	A scene observed from a given vantage point; can be preserved, neutralized, modified, or accentuated.
Viewshed	All the land and landscape elements that make up or affect a view from a given location or point; delineated by the horizon/silhouette line, enclosure by built or natural elements.
Vista	A confined view generally toward a terminal or dominant element or feature; may be natural or structural; may be created in its entirety and is therefore subject to close control.
Volatile solids	Readily vaporizable solids. Those solids that are combustible at 6000C.
Volatilization	The loss of gaseous components, such as ammonium nitrogen, from animal manure.
Warm-season plant	(1) A plant that makes most or all its growth during the spring, summer, or fall and is usually dormant in winter.(2) A plant that usually exhibits the C-4 photosynthetic pathway.
Waste management system	See Agricultural waste management system.
Waste storage pond	An impoundment made by excavation or earthfill for temporary storage of animal or other agricultural waste.
Waste treatment lagoon	An impoundment made by excavation or earthfill for biological treatment of animal or other agricultural wastes. Lagoons can be aerobic, or facultative, depending on their loading and design.
Water budget	An irrigation tool that keeps track on a daily basis of the amount of plant available water in the soil over a 12-month period. It sums soil water depletion by evapotranspiration using one of the climatonomic estimators and deducts water inputs from precipitation or irrigation. This yields the amount of irrigation water that needs to be applied to bring the soil back to field capacity within the root zone of the crop being irrigated. Water applications in excess of field capacity are assumed lost to percolation or rum-off.
Water management system	A planned system in which the available water supply is effectively used by managing and controlling the moisture environment of crops to promote the desired crop response, to minimize soil erosion and loss of plant nutrients, to control undesirable water loss, and to protect water quality.
Water quality	The excellence of water in comparison with its intended use or uses.
Water table	The surface between the vadose zone and the ground water; that surface of a body of unconfined ground water at which the pressure is equal to that of the atmosphere.
Watershed	(1) A total area of land above a given point on a waterway that contributes runoff water to the flow at that point.(2) A major subdivision of a drainage basin.
Wetlands	Areas characterized by soils that are usually saturated or ponded; i.e., hydric soils, and that support mostly water-loving plants; i.e., hydrophytic plants.
Yield	(1) The quantity of a product in a given space and/or time.(2) The harvested portion of a product.
Zoning (rural)	A means by which governmental authority is used to promote a specific use of land under certain circumstances. This power traditionally resides in the state, and the power to regulate land uses by zoning is usually delegated to minor units of government, such as towns, municipalities, and counties, through an enabling act that specifies powers granted and the conditions under which these are to be exercised.