GLOSSARY
alluvium: A general term for all eroded material deposited or in transit by flowing
water, including gravel, sand, silt, clay, and all variations and mixtures of these.
bedrock: Solid earth materials (limestone, sandstone, shale, etc.) exposed at the
land surface or overlain by unconsolidated soil materials such as clay, sand, and
gravel.
economic injury level: The lowest number of pests that will cause damage (crop loss)
equal to the cost of prevention.
economic threshold: A pest density at which control measures should be applied to
prevent an increasing pest population from reaching the economic injury level. (Pest
control is used only when the benefits of control exceed (or are equal to) the costs of
control.)
entrained materials: Substances such as sediment and agricultural or industrial
chemicals which are transported in the flow of runoff waters.
ephemeral gully: Small erosional channels formed on cropfields as a result of
concentrated flow of runoff water. These channels are routinely eliminated by tillage of
the field but return following subsequent runoff events.
flocculation: To aggregate or clump together fine particles into larger masses
which eventually settle out of suspension. Chemical additives can be used to accelerate
the process.
groundwater: The supply of freshwater beneath the earth's surface, usually in
aquifers. Because groundwater is a major source of drinking water, there is growing
concern over areas where leaching agricultural or industrial pollutants or substances
from leaking underground storage tanks contaminate groundwater. Wells and springs are
supplied by groundwater.
infiltration: The downward entry of water into soil.
Integrated Crop Management (ICM): A comprehensive system that considers economics
and the environment when selecting pesticides and nutrients. ICM emphasizes a more
comprehensive systems approach toward agricultural production rather than concentrating on
the benefits of individual practices. ICM is an informed decision making process that
takes into account production practices, economics, soid and water quality, nutrient and
pest management.
Integrated Pest Management (IPM): A process (based on scouting) that anticipates
and prevents pests from reaching economically damaging levels. Pests are controlled by
using all suitable tactics, including natural enemies, pest resistant plants, mechanical
management, and judicious use of pesticides. IPM leads to an economically sound and
environmentally safe agriculture. It is a component of ICM and a water quality practice.
leach: The movement of soluble components, such as chemicals, through the soil
profile by the actions of percolating water.
loess: Fine-grained soil material, consisting predominately of silt-sized particles,
deposited by wind. Loess soils are usually well drained.
moderately permeable soils: Those in which water moves downward through the soil
profile at a rate of 0.6 to 2.0 inches per hour.
nonpoint source pollution: Pollution arising from an ill-defined and diffuse source,
such as runoff from cultivated fields, grazing land, or urban areas.
nutrient management: A means of making sure that nutrients added match, but do not
exceed, the needs of the crop. Soil test results are used as a guide in this system.
palustrine: All non-tidal wetlands dominated by trees, shrubs, persistent
emergents,
emergent mosses, or lichens.
percolation: The downward movement of water through soil. Percolation is measured in
terms of permeability by distance per time (example: inches per hour).
pesticide: A chemical (natural or manufactured) used to kill unwanted organisms.
Pests can include insects, weeds, fungi, rodents, and other types of organisms. Three of
the most common types of pesticides used in production agriculture are herbicides,
fungicides, and insecticides.
residuum: Materials resulting from the disintegration, decomposition, and
weathering of bedrock.
riparian corridor: Strips of land, often narrow, that border creeks, rivers, or
other laterally flowing waters.
runoff: The discharge of surface water by both sheet and channel flow, expressed in
units of volume (examples: gallons or cubic feet).
slowly permeable soils: Those in which water moves downward through the soil
profile at a rate of 0.06 to 0.20 inches per hour.
SOC (synthetic organic compounds): Manmade organic chemicals. Some SOC's are
volatile and evaporate; others tend to stay dissolved in water rather than evaporate out
of it.
soil mapping unit: A type of soil displayed on a soil map and the basis for
delineations on a soil survey map. They often contain small areas of different soils that
are not large enough to draw on a soil survey map. Soil mapping units are generally
designed to reflect important differences in use and management.
somewhat poorly drained soils: Those in which water is removed slowly enough that
the soil is wet for significant periods during the growing season.
stakeholder: People impacted by management efforts or natural events. Stakeholders
may or may not be decision makers. For example, the stakeholders in Higginsville City Lake
Watershed include all public water users (residential and business), all agricultural
producers in the watershed, federal, state, county, city, and other local government
agencies responsible for water resources, and people who use the lake for recreational or
other non-drinking water purposes.
surface water: All water naturally open to the atmosphere (rivers, lakes,
reservoirs, streams, impoundments, seas, estuaries, etc).
watershed: All land and water within the confines of a drainage divide. Watersheds
are defined by the collection area for a specified location on a stream, such as a dam,
mouth of a stream, or any single point on a stream or drainageway. A drainage area is a
watershed.
water quality practice: A specific treatment that has the effect of improving water
quality. Combining water quality practices can have an additive effect greater than the
sum of the each practice alone.
well drained soils: Those in which water is removed readily but not rapidly. Water
is available to plants throughout most of the growing season.
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