Irrigation Glossary

Fertigation Application of nutrients through an irrigation system.

Field capacity Moisture remaining in a soil following wetting and natural drainage until free drainage has practically ceased.

Final infiltration rate Rate that (irrigation) water enters the soil at the surface.

Fine sand Soil textural class.

Fine sandy loam Soil textural class. Loams are gritty, moist, and retain water easily. In addition to the term loam, different names are given to soils with slightly different proportions of sand, silt, and clay: sandy loam, silty loam, clay loam, sandy clay loam, silty clay loam, and loam.

FIPT Acronym for female iron pipe thread.

Fitting Any connector (except a valve) that lets you join pipes of similar or dissimilar size or material in straight runs or at an angle.

Flood irrigation Method of irrigation where water is applied to the soil surface without flow controls, such as furrows, borders or corrugations.

Flow rate Rate of flow or volume per unit period of time.

Foot valve Check valve used on the bottom of the suction pipe to retain the water in the pump when it is not in operation.

Free drainage Movement of water by gravitational forces through and below the plant root zone. This water is unavailable for plant use except while passing through the soil.

Frequency distribution Measurement and presentation of various fractions of total water applied for selected depth ranges referenced to average depth applied.

Friable Soil consistency term referring to the ease with which the soil aggregates may be crumbled (in the hand), i.e. a friable soil is easily crumbled in the hand.

Friction factor, Christiansen Friction factor or coefficient used in the Christiansen Procedure to determine pressure loss in a multiple outlet piping system.

Friction factor (lateral) {psi/100 ft, m /100 m} Factor used to size pipe.

Frost protection Applying irrigation water to affect air temperature, humidity, and dew point to protect plant tissue from freezing. The primary source of heat (called heat of fusion) occurs when water turns to ice, thus protecting sensitive plant tissue.

Frost heave The upthrust of soil caused when moist soil freezes. Supply lines that do not extend below the frost line are subject to frost heave.

Frost line The maximum depth frost normally penetrates the soil during the winter. This depth varies from area to area depending on location and climate..

Friction factor , Christiansen Factor used to account for multiple outlets on a lateral pipe when computing friction loss via the Christiansen Procedure. ach equation.

Friction loss Amount of pressure lost as water flows through an irrigation system (due to friction against the pipe walls). Also, referred to as pressure loss.

Full irrigation Management of water applications to fully replace water used by plants over an entire field.

Fungicide Chemical pesticide that kills fungi or prevents them from causing diseases on plants.

Furrow Small channel for conveying irrigation water down slope across the field. Sometimes referred to as a rill or corrugation.

Furrow dike Small earth dike formed in a furrow to prevent water translocation. Typically used with LEPA and LPIC systems. Also used in non-irrigated fields to capture and infiltrate precipitation. Sometimes called reservoir tillage.

Furrow irrigation Method of surface irrigation where the water is supplied to small ditches or furrows for guiding across the field.

Furrow stream Stream flow in a furrow, corrugation or rill.

Fuse A safety device, located in an electrical box that shuts off power when a circuit overloads.