Water-Plant-Soil Relations - ag.arizona.edu

Design Step 3:

„ Each hydrozone
the plant with the

– highest water req
– lowest water req
– perennial?

Irrigate Base Plant

has a base plant. Is it
e

quirement? OR
quirement? OR

Choosing the B

Base Plant

Choosing Emis

„ You need to cons

– types of planting
– size of planted a
– soil type and infil
– traffic patterns
– maintenance
– watering window
– cost

ssion Devices

sider

g
area
ltration rate

w

Emitters - Types

Drip

Dense shrubs X
Single shrubs X
Small trees
Large trees X
Ground cover
Container
plants

Bubbler Micro- Drip
Spray Tube

X XX

X
XX

X

Emitter - Spaci

„ Depends on

– planting density
– soil type
– emitter flow rate
– minimum desired

ing

d watering depth

Emitter Spacing

„ According to Rai

– dripline
– low-volume sprin
– micro-spray pop-

„ Note

– minimum recomm
– maximum emiss
– recommended e

g - Dense Plantings

in Bird, best choices

nklers
-ups

mended watering depths
sion device spacing
emitter spacing

Emitter Spacing

„ According to Rai

– emitters
– bubblers
– pressure compen

„ Note

– the finer the soil,
runoff

– the more daily w
greater the flow r

– may need “wells

g - Sparse Plantings

in Bird, best choices

nsating emitters
, the greater the chance of
water a plant needs, the
rate required
s” or “troughs”

Emitter Placem

Tree

Emissio
Device
End Closure

ment

Shrub
¼ " Distribution Tubing
½" Distribution
Tubing

on
es

Emitter Placem

„ Use at least 2 em
„ Place emitters ev
„ Place emitters 3/

plant’s trunk and
„ Use stakes and c

hose/tubing for lo

ment Guidelines

mitters per plant
venly around plant
/4 the way between
d its dripline
caps at end of spaghetti
onger reliability

Calculating We

Wetted Area (ft2) =
Emitter Spacing

OR
Table 5-8, p. 40 ha

patterns and thei

NOTE: minimum we
the area of the pla

etted Area

= Emitter Spacing (ft) x
(ft) x 0.7854

as common spacing
ir wetted area

etted area should be 1/2
ant’s mature canopy.

Calculate numb

Minimum # emitter
Minimum Wetted A
Area Wetted by Em

ber of emitters

rs =
Area (ft2)
mitter (ft2)

Step 4. Calcula
Time

„ Determined by t
„ Process

– calculate run tim
– determine maxim
– determine irriga

ate System Run

the base plant

me per day
mum run time
ation interval

Calculate Syste

„ General Formula

Run Time per Day = W

„ Dense Plantings

Run Time per Day = W

„ Sparse Plantings

Run Time per Day = W

em Run Time

a

Water Requirement
Flow Rate

Formula

Water Requirement (in/d)
Adjusted EDR (in/hr)

s Formula

Water Requirement (gal/d)
Adjusted Flow (gal/h)

Example

You determined th
requirement for t
hydrozone is 0.2
are irrigating in Y
emitters spaced
Calculate the sys

hat the water
the base plant in your
2 inches per day. You
Yuma with 1.0 gph
18 inches apart.
stem run time.

Determine Max

= length of time the
deep percolation

„ Need to know

– flow rates of emi
– allowable deplet

• % soil moisture
deplete before w

• ROT: MAD app

Max Run Time = 0

ximum Run Time

e system runs before
n losses occur

itters
tion of soil

that you will allow the plants to
watering again = MAD
proximately 30-50%

0.000361*C*AW*D*S2
q*e

Example

You are irrigating in
18 inches in coar
emitters spaced
MAD is 35%. Wh
system run time

n Yuma to a depth of
rse soil with 1.0 gph
18 inches apart. Your
hat is the maximum
needed?

Determine Irrig

„ Compare calcula
per day to maxim

– calculated MUST
– if calculated MOR

to run system mo

Max Irrigation Inter

Maximum run time/Ca

gation Interval

ated system run time
mum run time

T be less than maximum
RE than maximum, need
ore than once each day

rval (days)=

alculated run time per day

Step 5. Irrigate
Plants

„ Already know syst
select emission de
the proper amount
base plants

„ May need to add m
emission device to
to plant during sys

e “Non-Base”

tem run time, therefore
evices that will supply
t of water to the non-

more than one
o get amount of water
stem run time

Design Step 6:

Lay Out System

„ Placing emitters
„ Checking hydraulics

Tips for Laying
Tubing

„ Use PVC to bring
„ Attach ½" tubing
„ Keep ½" tubing ru
„ Don’t exceed 4.0

Out Distribution

g water to hydrozone
to riser
uns at 250' or less
GPM flow in ½" tubing

Using In-Line T

Tubing

„ Tubing spacing is
same as emitter
spacing

„ Lay out tubing in a
loop (prevents
clogging)

„ Use flush caps
„ Install supplemental

emitters in tubing
for non-base plants

Irriga

ating Trees

Irrigating
Slopes



Container Plan

„ Run tubing up
through bottom of
planter

„ Attach multiple
emitters or bubbler

„ Run lateral tubing
along beam with
distribution tubing t
the plant

nts

r
to

Step 7. Calcula
Hydraulics

„ Make sure that th
pressure and flow
parts of the lands

– Pressure is influe
elevation and los
friction between
components.

– Flow is influence
emission devices

ate System

here is sufficient water
w available to irrigate all
scape.

enced by changes in
ss of pressure due to
water and system

ed by the number of
s on the lateral.