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Irrigation Glossary <br />rieja c.apacity trc.} Page 3 of 7 <br />Maximum amount of water that a soil can hold indefinitely against gravity. Put another way <br />it is the amount of water left in the soil after all the free water has had a chance to drain out <br />through the force of gravity. [%. in/ft, m1m]. <br />Flood Irrigation <br />Also known as wild flood irrigation. Water is turned into a field without any flow control such <br />as furrows, boarders or corrugations. This is the least efficient, least uniform and least <br />effective method of irrigation. <br />Flume <br />Flow measuring device for open channel flow. Water travels through a restriction and the <br />flow rate is determined using the water height on a staff gauge. <br />Full Cover <br />The point in the plant's growth stage where the canopy covers all available ground space <br />and using all available sunlight. Usually referrs to row crops. <br />Friction loss <br />Pressure tosses caused by friction of the water on the pipe walls and turbulence inside the <br />pipe. Friction losses are a function of the pipe length, the pipe's inside diameter, the pipe <br />material, and the flow rate. [psi/100ft, ft/100ft, kPa/100m] <br />Furrow Irrigation <br />Also known as rill irrigation. Water is applied to row crops in small ditches or channels <br />between the rows made by tillage implements. <br />Gated Pipe <br />Portable pipe that is placed at the top of the field. It has small gates in the sides that are <br />opened to allow water to flow into furrows. <br />' Hand Move <br />Typically 30 to 40 foot sections of portable aluminum sprinkler pipe with a sprinkler in each <br />section and that is moved manually. Labor requirements are higher than for all other <br />agricultural sprinkler systems. <br />Herd <br />Another term that irrigation designers use for pressure. See conversions. [ft or m of water] <br />Infiltration Rate <br />Rate at which water can enter the soil. Usually measured in units of depth per unit time <br />[in/hr, mm/hr] <br />Intake Rate (Basic) <br />Rate at which water enters the soil after infiltration has decreased to a low and nearly <br />constant value. This value should be used for sprinkler and drip irrigation system designs. <br />[in/hr, mm/hr] <br />Irrigation Efficiency <br />Proportion of the water that is beneficially used to the irrigation water applied. [%, decimal] <br />Irrigation Scheduling <br />Process of determining when to irrigate and how much. This can be done by monitoring the <br />soil, the crop, or calculating water use (evapotranspiration). The goal is to schedule <br />irrigation timing and amounts such that the soil' water content remains between field <br />capacity and the management allowable deficit- <br />nttp://irrigation.wsu.edu/glossary.php <br />tn1200s <br />82