Full Product Manual

Table Of Contents
GLOSSARY
E
Glossary Page 95
1/2" polyethylene
tubing
a low-volume distribution component typically used to bring water from a Schedule 80
riser into a hydrozone.
1/4" distribution
tubing
a low-volume distribution component typically used to bring water directly to plant roo
t
zones; also known as “spaghetti” tubing.
allowable depletion (also known as Management Allowable Depletion) the percent of soil moisture that an
irrigator will allow to be depleted before irrigating again; selection of a low allowable
depletion requires more frequent irrigation of smaller amounts. A higher allowable
depletion will require fewer irrigations of larger amounts. Generally, allowable
depletion should not exceed 30-50 percent for a low-volume irrigation system.
base plant the plant that requires the least amount of water in a given planting scheme, typically
is the predominant plant in a dense planting scheme.
capillary action the primary force in spreading water horizontally through soil.
compression fitting a fitting used to connect 1/2" poly drip tubing in a low-volume system; compression
fittings are attached to the outside of the tube so that the connection becomes tighter as
the pressure increases.
control zone in a low-volume system, a collection of components that controls the flow and pressure o
f
water to the hydrozone; the control zone includes a ball valve, an in-line WYE filter, a
remote control valve and a pressure regulator.
controller a device that automatically opens and closes the valves in an irrigation system accordi
n
to a pre-set program.
crop coefficient
(also known as the Plant Factor, or K
c
)
an adjustment factor used to equate actual plant- water use to referenced PET; a given
plant type may use less water than the referenced ET rate for an area. Multiplying the
plant's crop coefficient by the referenced ET rate adjusts ET to the actual plant water
use. Crop coefficient values are not widely available for landscape plants, but they are
grouped into one of three categories: low, medium or high water usage. See Chapter 4 fo
r
information on calculating crop coefficients.
distribution
component
a low-volume irrigation component that brings water to the individual hydrozones and
plants; distribution components can include 1/2" polyethylene tubing, 1/4" spaghetti
tubing, compression fittings and flex risers.
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