[The Cooperative Soil Survey] Soils Tutorial: Glossary

Glossary

Definitions from the Soil Science Society of America (SSSA)

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

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.

Impervious soil A soil through which water, air, or roots penetrate slowly or not at all. No soil is absolutely impervious to air and water all the time.

Infiltration The downward entry of water into the immediate surface of soil or other material, as contrasted with percolation, which is movement of water through soil layers or material.

Infiltration capacity The maximum rate at which water can infiltrate into a soil under a given set of conditions.

Infiltration 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.

Intake rate The average rate of water entering the soil under irrigation. Most soils have a fast initial rate the rate decreases with application time. Therefore, intake rate for design purposes is not a constant but is a variable depending on the net irrigation application.

Interfluve The area between two adjacent streams flowing in the same general direction or any elevated area between two drainageways.

Irrigation Application of water to soils to assist in production of crops.

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.
Impervious soil	A soil through which water, air, or roots penetrate slowly or not at all. No soil is absolutely impervious to air and water all the time.
Infiltration	The downward entry of water into the immediate surface of soil or other material, as contrasted with percolation, which is movement of water through soil layers or material.
Infiltration capacity	The maximum rate at which water can infiltrate into a soil under a given set of conditions.
Infiltration 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.
Intake rate	The average rate of water entering the soil under irrigation. Most soils have a fast initial rate the rate decreases with application time. Therefore, intake rate for design purposes is not a constant but is a variable depending on the net irrigation application.
Interfluve	The area between two adjacent streams flowing in the same general direction or any elevated area between two drainageways.
Irrigation	Application of water to soils to assist in production of crops.