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July 1986


I Disk(s) under separate cover


Circular 720


A User's Guide to IRRIGATE
An Irrigation Decision Aid

Central Science
Library

JAN 30 1990

University of Florida \ COMPUTER SERIES


Mike Monson, W. G. Boggess, and J. W. Jones


101
F636c
720
guide


Extension Service / Institute of Food and Agricultural Sciences / University of Florida / John T. Woeste, Dean










Table of Contents


Introduction
Hardware and Software Rsequirements
Getting Started
Operating Conventions
Sample Run
Introductory Screens
Entering a Field Description
and Irrigation History
Entering a Rainfall History
running IRIGATE
Appendix A. Files on the Diskette
Appendix B. Crop Growth Stage Descriptions


UjVfASjjY









A User's Guide to IRRIGATE: An Irrigation Decision Aid
by
Mike Monson, W.G. Boggess, and J.W. Jones


IRRIGATE is a microcute program designed to provide information on
the profitability of an i1a n applcation during the qrowg season for
orn or soybean. The evaluatn is based on the value of the potential
increasee in yield from the irri consider previous rainfall and
S a ige testaage of e crop, probaly of rainfall, and the

The value of irrigation is based on its effect on soil water avail-
ability reactive to the crop's needs i a particular growth stage. By eval-
uatrg. irrigation, with the appropriate growth stage sensitivy t o water
ab ity, the user is better able to determine the crtlcal tlnes for

ihe irrigation decision is complex. You may not need t? irrigate the
day after a r nstom but what are the returns from irrigation if it rains
eay after? RFIG.TE is designed to quickl evauate different weather
and irrgatn possibilities before you ma a final irrigation decision.
IRRIGATE evaluates the effect of irrigation for three days after it is
applied, and assumes sufficient water availability for the reminder of the
season, and adequate fertilizer and pest control. The returns from
rrga n as predicted by the model therefore rre ent a maximum. value.
Srogw stage sensitivities to water valaility are for relatively
short peods of time and may underestimate the value o irrigation during
an d d drought.
Hardware and Software Requirements
This software requires an IBM1 PC or X? (or cm tible) computer with
at least 64K bytes of random aess memory. In iti he user needs
PC-DOS 2.0 or a more recent version (MS-DOS for ) and IBM BASIC
programming language.
Getting Started
mk IGA is distributed on a single diskette. The first step is to
make a workg diskette from the original. The following steps should be
used to make a working diskette:
1. FORMAT a new diskette wth, the /S option
2. Copy the distribution diskette onto the newly formatted diskette
using the ISKOPY command See Appendix A).
3. Copy the file "BASICA.CC rom e BASIC diskette using the COPY
crnmand.
4. Place the distribution diskette in a safe place
Details on the use of FORMAT, COPY and DISKCOPY commands are given in your
DOS manual.

IRRIGATE is run by placing the working diskette in the default disk
dri. Press the , , and keys, and the program will
=e A "break" will leave the computer in BASIC. Press the key to
restart the program.
Single character entries such as menu selections and responses to

1 IM is a registered trademark of International Business Machines, Inc.









If a printer is available and you wish to have a copy of a particular
screen for later reference, press the and keys for a
printout.
The following pages contain screen images from a sample run through the
program. Use responses are underlined in the following sample run. The
have been inserted to explain the operation of the software. Please work
through this sample to become familiar with IRRIGATE.
Sample Run
Once IRRIGATE starts, .the message "One moment, please" will appear on
the screen as the program is being loaded. This will be followed by:

EXECUTION MENU
OPTIONS:
A. Enter mdify field description
and/or rriation history
B. Enter or modify. rainfa history
C. Run IRRIGATE using: Field-
Rainfall history-
D. View Introduction
E. Quit (Return to DOS)
OPTION?->D Be sure the Caps Lock is on.

This is the Execution Menu. The function of each option is explained
below:
Option A: Vse this option to enter a new field description and
irrgation histo, or modify an existing such as
adding an i gton event. This oton is also used
to select the field and irigaton ry ouwish o
use with IRRIGATE. The last field selected with uh.s
tion n Option C as the field to be used with

Option B: Use this option to enter a new rainfall history or modify
an existing one, such as adding a rainfall event. This
option is also used to select the rainfall history you
wish to use with IRRIGATE. The last rainfall history
selected with this option appears in option C as the
rainfall history to e used with IRRIGAm. .
Option C: This ion runs he ion decision analysis using
the field and irrigation itory and rainfall history
shown. If either a field or rainfall history has not
been selected, the program runs Option A or B and returns
to the Execution Menu.
Option D: This option displays a description of IRRIGATE, its
purpose, acknowledigements and who to contact with
questions or for help with problems.
Option E: This option terminates the current session and returns
the computer to DOS and the "A>" prompt.
Enter "D" to view the introduction before using any other option. If
you et no response press te iput requests must be in capital letters.









Screen 1. Purpose of the program.


IRIATE"
A Microcomputer Irrgation Decision Aid
by
Mike Monson, W.G. Boggess, and J.W. Jones

Institute of Food and Aricultural Sciences
University of Florida
Gainesville, Florida 32611
(904)-392-1845
Cpyriht 1985 by IFAS, UF

This program was written to evaluate the profitability of irrigation
during the growing season for co o soybeans under alternative prices
weather forecasts, crop and so conditons. This evaluation is based
on a crp owth and so water balance simulation model using rainfall
and irrigafcon data provided by the user.
PRESS SPACE BAR TO CONTINUE:

Screen 2. Required inputs for the model.

The program initially requires inputs for:

Field description:
Select r proved for soil type, crop, planting date,
xum yield, and irrigation system.
Irrigation histo:
Matrcain a record. of the date and amount of irrigation applied

Rainfall history:
Maintain a record of the date and amonnt of rainfall 3ece4ved
for each field. A general rainfall history can be maintained
for use with all fields receiving identical rainfall.
The user inputs the potential irrigation decision date. IRRIGATE uses
the field description and irrqatioand rainfall histories to simulate crop
growth and soil water balance from planting to the current date.
PRESS SPACE BAR TO CONTINUE:









Screen 3. Output from the program.

The user verifies or provides alternate values for:
I. Crop status from simulation model
II. Short-term weather forecast
III. Input costs and crop price
IV. Irrigation amount to consider

IRRIGATE provides an economic evaluation of the profitability of irrigation
by calculating the expected returns from .irrigation. This recommendation is
based on the current crop status, potential yield increase,, crop and input
prices, weather outlook, and the cost and amount of irrigation considered.
Because IRRIGATE's recommendations depends on these factors the user
is encouraged to ccmpare recommendations with alternative values before
making a final decision.

data The best become familiar with GATE is by using the sample
data diskette with the User's Guide.
PRESS SPACE BAR TO CONTINUE:

Screen 4. Special acknowledgements.

ACMKOWLEDGEENTS
This software is based on the procedure presented by 0. P. Swaney,
J. W. Jones W. G. BoggeGs,. G. Wilerson, and J. W. Mishoe in 'Real-Time
ration .6isio Analysis Using Simulation', Transactions of the ASAE
26(1983) pp.562-568.
The authors wish to express appreciation to Dr. Jerry Bennet of the
Agronoy Department, University of lorida, for assistance in development,
evaluation, and testing of the program.
. Additional thanks to Nick Bretagna II, who developed much of the
initial programming.
For assistance, please contact:
Dr. W.G. Boggess
1099 McCarty Hall
University of Florida
Gainesville, Florida 32611
(904) -392-1845
PRESS SPACE BAR TO CONTINUE:









Screen 5. Disclaimer and condition of release.

DISCLAIMER
The University of Florida (UF), Institute of Food and Agricultural
Sciences (AS), and Flor.d Cooperative Extension Service (FCES) shall have
no liability or responsibility to coperator or any other person or
entity with respect to any. ability, loss, or damage caused or alleged
to be caused directly or i rectl y programs released by IFAS for sale or
for cooperative use including but nor limited to any interruption of
service, loss of business, or anticipatory profits or consequential
damages resultuing from use or. operation. And in no event shall FCES be
liable for loss of profits, indirect, special, or consequential
damages arising out of any breech of the agreement or obligations of this
contract.
CONDITION OF RELEASE OR SALE
All computer software distr' by IFAS or FCES are on an 'AS IS'
basis without warranty. Distribution or resale without written
per mission of the department of origin is not permitted.
PRESS SPACE BAR TO CONTINUE:

This is the last screen of the introduction. You will return to the
etion Menu. Select Option A to follow how a field description with
history is entered.
Entering a Field Description
The first step in using IRRIGATE is describing the field to be con-
sidered. Byselecting Option A from the Execution Menu, you can enter or
review a field description. This option provides menus for soil type,
crop, planting date, maximum yield, and irrigation system, as well as
recording the irrigation history associated with the field. Once entered,
this description is stored on t&e diskette for access by-IRA= There
should be enough room for at least twenty fields on the diskette (see
Appendix A).
After selecting Otion A the program requests a field name. Use
names with eight characters or less that you will remember.
Screen 1.
Enter Field file name:
Field-OOM

If the field description has already been entered and you are only
making somre changes or you wish to enter additional irrigation data, the
program will proceed to Screen. 8. The following screens illustrate how
the sample field CRN was entered.
Screen 2.
lerecogized. Would you


This indicates no file of the name you entered in Screen 1 was found.
If you mistyped the name,. edter "N" to return to Screen 1. If you are
entering a new field description, enter "Y" for:










Screen 3.
Field-C0RN
1. Soil type :
2. Crop :
3. Variety class
4. Planting date :
5. Maximum yield
6. srrrationsystem :
1 .ILoamy sands
2 .Coarse sands
3 .Wet loamy
4 .Sands
Specify soil type(l- 4 )->3

This is the table of characteristics that will describe the field.
Enter the number corresponding to the appropriate soil type. Then:
Screen 4.


Enter the number co ding to the crop planted. At this time
wheat and peanuts are not available. Next:

Screen 5.


Field-CRN
1. Soil type :
2. Crop :y
3. Varit class :
4. Planting date :
5. Max#=m. yield :
6. Irrigation system:
1 130-day
2 123-day
3 115-day
4 (N.A.)
Specify variety(l- 4 )->.


Wet loamy
Corn
0 / 0 / 0 (Too Early)
0


Enter the maturity class number that most closely corresponds to the
seed variety planted. Then:


Field-CORN
1. Soil type: e
2. Cro
3. Variety class :
4. Planting date :
5. Max#=lm yield :
6. Irrigation system :
1 .Soybeans
2 .Corn
3 .Peanuts(N.A.)
4 .Wheat(N.A.)
Specify crop type(l- 4 )->2


let loamy


0









Screen 6.
Specify the planting date:
->o / / <-

(Two digits, with zero for the first digit if number is 1 through 9,
please.)

Enter the number (01 to 12) of the month of planting. Then:

Specify the planting date:
->03 / 0 / <-

(TWO dgits, with zero for the first digit if number is 1 through 9,
please.)


The month you entered now appears. Enter the day of the month. Then:


Specify the planting date:
-> 03 / 06 / q5 <-

(Two gits, please.)

Enter the year, then:


Specify the planting date:
->03 / 06 /85 <-
-> Friday <-
This is all correct? (Y/N) ->X

The program calculates the weekday to help verify that the date
entered is correct. If you mistyped one of the numbers enter "'N" to
return to Screen 6. If all i correct, enter ."Y." ( ite: entr all
dates for irrigation and rainfall and irrigation decision date in a
similar manner. Sometimes the year will already be present to speed data
entry.) Next:










Screen 7.


As you car) see, the program calculated a maximum yield for the crop
based on the soil type, variety, and planting date. In the event that your
planting date falls outside the rane of data used in the model, "(too
early)" or "(too late)" will appear ter the planting date in the table.
The earliest and latest planting dates for corn are February 25 and April
25 and March 21 and July 19 for soybeans. The number in parentheses
afer the planting date is the Julian date or day of the year (January
1-1, December 31-365 or 366).
Don't worry if the maximum yield is incorrect because ou can c
.ts value later. Remember ths the maximum yield with sufficient f e
ilizer, pest control, and irrigation. Now enter the number corresponding
to the irrigation system most appropriate:
Screen 8.
Field-CORN
1. Soil type : Wet loamy
2. Crop: Corn
3. Variety class : 130-day
4. Planting date : 3 / B / 85 ( 65)
5. Maxmum yield : 211
6. Irrigation system: Center-Pivot,Medium Pressure (75 PSI)
Change any of the above?
(Entr 'N' or item # above)->N

Enter the number of any item you wish to change, one at a time, to
return to the appropriate previous step. You may want a printout of this
table for future reference. If everything is correct, enter "N" to
proceed with recording any irrigation data:

Screen 9.
IRRIGATION HISTORY-c0RN
DATE AMNT (INCHES)


Any further irrigation information? (Y/N) ->X


This is the irrigation history of the field. Of course, there is no
information for a new field. If you have no new irrigation data to enter at
this time, enter "N" to return t9 the execution menu. Enter "Y" to add any
new data or to edit existing irrigation data. The following steps
8


Field-CORN
1. Soil type: Wet loamy
2. Crop : Corn
3. Variety class : 130-da
4. Planting date : 3 / 85 (
5. Maximum. yield : 2
1 .CentegaPivon teum :
1 .Center-Pivot,Medimw Pressure (75 PSI)
2 .Center-Pivot,Low Pressure (40 PSI)
3 .Traveling Gun,Cable-Tow
4 .Traveling Gun,Hose-Tow
Specify irrigation system(1-4) ->1.


65 )









Ulvstrate how the irrigation history for this field was entered. If no
=rr4.gaton data has been entered, the program proceeds directly to add an
ir rgaon event if a "Y" is entered. Otherwise, the following will appear
at t bottom of the irrigation history display:

Change, Add, Insert, or Remove? (C/A/I/R) ->A

To add data enter "A." Then:

Specify Irrigation Date 1 :
->2 /IJ, / 85 <-
-> Sunday <-
This is all correct? (Y/N) ->Y

The program requests the date of .the next irrigation event. Enter the
month an day as previously shown. The year may already appear. Then:

Okay... On 3 / 10 / 85 ( 69 )
How much did you irrigate? (in.)


Enter the amount of irrigation applied. Next:

Okay... On 3 / 1 /. 85 ( 6)
How much did you irrigate? (in.)
his is all correct? (Y/N) ->Y

If the date or amount is incorrect, enter "N." If all is correct,
enter "Y." Then:

IRRIGATION HISTORY-CORN
DATE AUNT (INCHES)
# 1. 3 / 10 / 85 ( 69 ) 1.50
Any further irrigation information? (Y/N)->y

The addition you entered is now displayed. Enter "Y" to edit the
history. The edit line will appear at the bottom:











IRRIGATION HISTORY-CORN
DATE AMOUNT (INCHES)
# 1. 3 / 10 / 85 ( 69 ) 1.50
Change, Add, Insert, or Remove? (C/A/I/R) ->:

Enter "C" to change information in the irrigation history. The
following will appear beLow the history.

Which date # to change? (1- 1 )->.1

Enter the number you wish to change. Enter "0" to return to
Screen 9.

Old Date/Amount : 3 / 10 / 85 ( 69 ) 1.50
Specify Irrigation Date 1
->D3 /fU / 85 <-
-> Monday <-
This is all correct? (Y/N)->X

Enter the new date or the old date if you just want to change the
mount. Then:

Okay... On 3 / 11 / 85 ( 70 )
How much did you irrigate? (in.)



Enter the appropriate amount. Then:

Okay... On 3 / 11 / 85 ( 70)
How much did you irrigate? (in.)
->1
This is all correct? (Y/N)->X

tf the changes are correct, enter "Y" to return to Screen 9. If the
data s incorrect, enter "N." If an. event was left out, it may be inserted.
Assume that the current irrigation history consisted of two events.

















If an irrigation of 0.5 inches was applied on 3/15/85 but not
recorded, the history may be edited to include the event. Enter "Y" for
the edit options. The following will appear below the irrigation history:


Change, Add, Insert, or Remove? (C/A/I/R) ->I

You can insert the event by entering "I." Then:

Which date # to insert? (1- 2 )-> 2

The omitted event (3/15/85) should be second in the irrigation
history If you enter 0," the program returns to Screen 9. Enter the
appropriate number. Then:

Specify Irrigation Date # 2 :
->9 /.,U / 85 <-
-> Friday <-
This is all correct? (Y/N) ->

Enter the date to be inserted. Then:

Okay... On 3 / 15 / 85 ( 74)
How much did you irrigate? (in.) ->._5

Enter the amount. Next:

Okay... On 3 / 15 / 85 ( 74)
How much did you irrigate? (in.) ->0.5
This is all correct? (Y/N)->X

If all is correct, enter "Y" aid the inserted date will appear in
the irrigation history with subsequent irrigation events ren=m e ared.

11


IRRIGATION HISTORY-CORN
DATE AMOUNT (INCHES)
1. 3 11 85 70 1.00
2. 3 / 20 85 79 1.50
Any further irrigation information? (Y/N) ->











IRRIGATION HISTORY-CORN
DATE AMOUNT (INCHES)
1. 3 /11 /85 70 1.00
2. 3 15 85 74 0.50
3. 3 20 85 79 1.50
Any further irrigation information? (Y/N) ->

If an irrigation event was inadvertently entered in the history, enter
l"Y" to edit the story. Then:

Chane, Add, Insert, or Remove? (C/A/I/R) ->

Enter "R" to remove an event from the irrigation history.

Which date # to remove? (1- 3 )->2

Enter "0" to return to Screen 9. Enter the event number to be removed.

Old Date/Amount : 3 / 15 / 85 ( 74 )..... 0.50
Irrigation Date 2 to be removed
This is all correct? (Y/N)->Y

The irrigation event to be removed is displayed. Enter "N" if you do
not want this event removed. Enter "Y" to remove the event. Then:

IRRIGATION HISTORY-CORN
DATE AMOUNT (INCHES)
1. 3 11 85 70 1.00
2. 3 20 85 79) 1.50
Any further irrigation information? (Y/N)->N

The irrigation history is displayed with the event removed and subse-
nt irrigation events r bered. Enter "N" to return to the Execution
Up to 35 irrigation events ca. be entered per field. The field name
entered earlier should now appear in Option C as the field to use with
IRRIGATE.









Entering a Rainfall History
Rainfall histories should contain the dates and amounts for each
rainfall event that occurs on a field. However, rainfall histories are
recorded as files separate fro the field description and irrigation
history file (See Apendix A). If several fields receive identical rainfall,
one history with a different name can be maintained for use with each field.
If you hve not entered a field name during this session, the first
screen tha will appear when you select Option B from the Execution Mnu
be Screen 2. f you havealready entered a field from the ton
Menu (Option A), then the first screen after you select option B wil be:

screen 1..
w to use the Rainfall History for
Field-CPRN? (Y/N) ->_N

If Vou enter "Y" this verifies that the field description fie and
rainfall history have the same name. If you wish to use a raifall history
with a different name, enter "N." Then:

Screen 2.
Enter the Rainfall History you wish to
use->MPLE

SAMPLE is th name of an example rainfall history already recorded on
the diskette. Ths rainfall history can be used with either o the example
fields. If a rainfall history with the name entered here. is found, the
program proceeds to Screen 4. If you are entering a new rainfall history,
the program responds with:

That name #s not recognized, Would you
ike to initialize Rainfall History-SAMPTLE?(Y/N)-> I

This indicates that no rainfall history of the name entered was found
on the diskette. If you made a, typ error, as in this example, enter "N"
to return to Screen 2. If you wish toe a new rainfall history with the
name isplayd, enter "Y." From this point, enter rainfall information just
like irrigation data from the previous section.
Screen 4.
RAINFALL HISTORY-SAMPLE
DATE AMOUNT (INCHES)
# 1. 2 /28 / 80 ( 59) 1.20

#89. 11 / 22 / 80 (327 ) 0.05
Any further irrigation information? (Y/N) ->N

Up to 99 rainfall events can )be stored in a rainfall history. You can
press the Ctrl and Num Lock keys in combination to t;enoorarily stop the
display, Simly press the space bar to resume the display. The rainfall
events in SAMPLE are from Gainesville, 1980.









Running IRRIGATE
IRRIGATE is the actual irrigation decision evaluation section of the
a. Usi the characteristics and irrigation history of the field
select wSth. ion and the rainfall history selected wth Opton B a
potential irrigation is evaluated. The user specifies an irrigation date
and amount to oe considered. IRRIGATE siulates and yerifies the parent
state of the crop and soil water availabiliv at the time of the decision,
and requests user inrpt on weather conditions in the future. This
nfoKmuaonis used to predict the maximum potential increase in yield as a
result of the irrigation being considered.
If you ave not selected a gield and rainfall history to use before
selecting on C from the Execution Menu, the program will go to Option A
to select afield and return to the Ex tion Menu. A fie name will
appear in Option C. If you have not selected a rainfall history, the
program will go to Option B to select a .rainfall history and return to the
Execution Menu. The selected rainfall history will appear in Option C. Be
sure that the proper field and rainfall history are being used before
selecting Option C. Then:

Screen 1.
Enter the date for which the
irrigation decision is to be made
->.Q /1 / 85 <-
-> Monday <-
Tis is all correct? (Y/N)->Y

Enter the date you wish to consider just as you entered previous, dates.
If you have incorrectly entered the date, enter 'N." If you are using the
example rainfall history SAMLE the rainfall extends frog February through
November. However, IRRIGATE will only use the rainfall information between
the planting date and the decision date. If the decision date is correct,
enter "Y" and IRRIGATE will begin as follows:
Screen 2.
Field-CORN Rainfall History-EARLY Decision Date- 6 / 10
Now figuring soil water balance...
Now on Day: 66
Decision Day: 161
Current Growth Stage: 0 Month: 3

The field and irrigation history name, rainfall history, and decision
date are displayed at the top of -the screen. The current date being
simulated is displayed followed by the Julian date for the decision day.
The current growth stage displayed corresponds to those described in
B. The month is also displayed. After the crop has emerged (Growth
Stage 1) an additional line will be displayed:


I











Field-CORN Rainfall History-EARLY Decision Date- 6 / 10
Now figuring soil water balance...
Now on Day: 78
Decision Day: 161
Days Until Visible Wilt-15
Current Growth Stage: 1 Month: 3

A rough approximation of days until vi ible wilt occurs is displayed.
This number may increase or decrease depending upon rainfall, irrigation,
and crop growth. If the wilting point is reached, then:


Field-CRNM Rainfall History-EARLY Decision Date- 6 / 10
Now figuring soil water balance...
Now on Day: 149
Decision Day: 161
Days of Visible Wilt= 3
Current Growth Stage: 1 Month: 4

The number of days of visible wilt according to the simulation is
displayed. This number will increase until rainfall or irrigationn occurs.
As you use =RGAE, you may find that irrigation to avoid visible wilt is
not always profitable.
The days count up until the decision day is reached. Then:

Screen 3.
According to IRRGATE, now the crop
should be in Period 4 and display the
following characteristics:
Kernels in milk or soft-dough stage
Is this correct? (Y/N) ->Y

A verbal description of the calculated growth stage is displayed Since
the value of irrigation depends on the growth stage, it s important that
the correct stage is considered. If the displayeT stage is correct, enter
"Y" to proceed to Screen 4. If it is not correct,enter "N" to select a more
appropriate growth stage as follows:


Okay ... Select one:
3 : Tasseling cmlete; Blister kernels developing
4 :Kernelsn miU or soft-dough stage
5 : Kernels in hard-dough stage; Black layer present
Enter most appropriate #:->4










Enter the most appropriate growth stage number displayed that corres-
ponds to the actual stage of the crop. Then:
Screen 5.
According to IRRIGATE the crop has
exhibited visible wilt at midafternoon
for the past 7 days...
Is this correct? (Y/N)->X


The program displays the calculated days of visible wilt. This
indicates crop stress and may affect the value of irrigation. If this is
correct, enter "Y" to proceed to Screen 6. If not, enter "N." Then:

Oay.,.. for how many days has the
crop exhibited wilt?->2

Enter the actual number of days of observed visible wilt. Then:

Screen 6.
According tIRRIGATE 100 % of
the ground shaded by the crop.
Is this correct? (Y/N)->y

If this is correct enter "Y" to proceed to Screen 7. If not, enter "N"
for:


Okay... About what percentage of the
ground is shaded by the crop?->.1Q0

Enter the actual percentage of the ground shaded by the crop. Enter
"30" for 30%, not ".30." Then

Screen 7.
Over the next three days, do you expect
temperatures to be:
1.- Warmer than normal
2.- Normal
3.- Cooler than normal
Enter 1, 2, OR 3-> 2

The effect of irrigation depends on temperature. Enter your expecta-
tions for temperature over the next three days. You may wish to consult a
weather forecast for this and the following:










Screen 8.


Cloud cover also affects the value of irrigation. Enter your expecta-
tions of cloud cover for the next three days. Then:

Screen 9.
Statistics indicate that if it pains,
one should expect about 1.14 inches.
Is this correct? (Y/N) ->

This information is based on historical Florida weather patterns. If
this seems reasonable enter "Y" to continue to Screen 10. If you have
better information, enter "N." Then:


Statistics indicate that if it rains,
one should expect about 1.14 inches.
Okay... How much rain? (in.) ->1,;4

Enter the amount of rain you expect the field to receive if a rainfall
does occur. Then:
Screen 10.
Statistics also indicate that there is
a 60 % chance of rain over the next
three days.
Is this correct? (Y/N)->X

This is also based on historical data. If it seems reasonable, enter
"Y" to proceed to Screen 11. If not, enter "N." Then:

Statistics also indicate that there is
a 60 % chance of rain over the next
three days.
Okay... What chance of rain? (%) ->6Q

Enter your expectation on the probability of rain. You may have better
information from a weather forecast. Then:


Over the next three days, do you expect
the sky to be:
1.- Clearer than normal
2.- Normal
3.- Cloudier than normal
Enter 1, 2, OR 3-> 2









Screen 11.
Assuming you irigate, how much will
you irrigate? ( nes) ->

Enter the amount of irrigation you wish to consider. This amount
should be the amount delivered to the soil. Then:

Screen 12.
Enter expected selling price
of the crop ( for default value)
->2".75 Default=$3.00/Bu.


If the default price is O.K., just press the key. If not,
enter the correct price. Do not enter a "?" sign. Then:

Screen 13.
Enter the price of fuel ( for default)
->125 Default=$l. 10/Gal.

Press the key for the default price or enter the correct price.
Do not enter a "$" sign. Then:

Screen 14.
Enter the present wage rate ( for default)
->4.50 Default=$4.00/Hr.

Press the key for the default wage rate or enter the correct
price. Do not enter a "$' sign. Then:
Screen 15.
According to this data, the cost of
applying 1 inches of water per acre
IsS 6.97 Would you like to change
this value? (Y/N) ->f-

This value is based on data from the Irrigation Cost Generator2
developed at the University of Florida. This #s an estimate of variable
cost, including fuel, labor, repairs, and lubricants, and represents the
marginal cost of the irrigation being considered. If it is correct, enter
"Y" to proceed to Screen 16. If not, enter "N." Then:


kay... How much will it cost to apply 1
inch of water per acre?->6.97


2 d'Almada, P.J. G.D. Lynne, and A.G. Smaj strla, "A User's Manual for
the FARM Systems Lb Irrigati9n Cost. Generator, Economic Information Report
157, IFAS, University of Florida, Gainesville, Fla. 32611, Jan. 1982.
18










Enter the cost of applying the total amount of irrigation per acre you
specified. Do not enter a "$" sign. Then:
Screen 16.
IRRIGATE predicts the yield change from
irrigation as a percentage of. the maximum yield.
The mxi yield previously entered for this
fields 211 bushels.
Would you like to change this value? (Y/N) ->_

IRRIGATE predicts the increase in yield from irrigation as a percentage
of the maximum yield. You may wis1 to try different v .lues. This will not
change the maximum yield stored in the field description. If this is
correct, enter "Y" to proceed to Screen 17. If not, enter "N" for the
following:

IRRIGATE predicts the yield change from
irrigation as a percentage of the maximum yield.
The max yield previously entered for this
field is 211 bushels.
Would you like to change this value? (Y/N)->Y
New maximum yield->211

Enter the maximum yield you wish to consider. Then:
Screen 17.
Field-CORN Rainfall History-EARLY Decision Date- 6 / 10
CROP STATUS
1. Growth Stage: Kernels in milk or soft-dough stage
2. Days of Visible Wilt 7 Days
3. Ground Cover 100 %
Chane any of the above?
(Enter or item # above)->_N

If you wish to change any crop status information entered earlier,
enter the appropriate numer to return to one of the previous steps. If
there are no changes, enter "N." Then:

Screen 18.
Field-CORN Rainfall History-EARLY Decision Date- 6 / 10
WEATHER CONDITIONS
1. Temperature Normal
2. Cloud Cover Normal
3. Probable Rain 1.14 inches
4. Rainfall Probability 60 %
Change any of the above?
(Enter WN or item # above)->N





If you wish to change any of the weather information entered earlier
enter the appropriate number to return to one of the previous steps. If
there are no changes, enter "N" to continue:
Screen 19.
Field-CORN Rainfall History-EARLY Decision Date- 6 / 10
PRICES AND COSTS
1. Amount of Irrigation. 1 inches
2. Irrigation Cost ( 1 in.) $ 6.97 /Acre
3: Crop are 2.79 .B5 ,
4. Fuel ce 1.25 /Gal.
5. Wage Rate 4.50 /Hr.
6. Maximum Yield 211 B./Acre
Change any of the above?
(Entr N or item # above)->_N

The irrigation amount, cost, prices, and maximum yield entered earlier
are dispy If any are incorrect, enter the appropriate number to
return to one of the previous screens. If there are no changes, enter "N"
for the following:
Screen 20.
Field-ORN Rainfall History-EARLY Decision Date- 6 / 10
Now figuring soil water balance...
working on no rain or irrigation
Nr on raiU wi, no. rrgation..
Wor.ng on Irrigatin .wth no rain
Wor ix on both irrigation and rain

IRRIGATE simulates the future under the four alternatives shown.
IRRIGATE assumes that the irrigation amount being considered is allied on
the first day, and the rainfall occurs on the second day. From these four
alternate futures, the following is calculated:
Screen 21.
Field-OQR Rainfall History-EARLY Decision Date- 6 / 10
SUMMARY EVALUATION: No Rain With Rain
2nd Day 2nd Day
Yield Difference /
from Irrigation 4.81 B./A. 2.96 B./A.
x Crop Price $ 2.75 /B. $ 2.75 /B.

Gross Return $ 13.22 /A. $ 8.14 /A.
Var Irr. Cost -$ 6.97 /A. -$ 6.97 /A.
1 in./Acre)

Net Return $ 625 /A. $ 1.17 /A.
x Probability 40 % 60 %

Expected Return- $ 2.50 /A. $ 0.70 /A.
PRESS SPACE BAR TO CONTINUE

Th' s is a summary table showing the y2eld difference as a result of
irrigation without and with the expected rainfall. The variable cost of
irrigation is subtracted from the grss returns to give the net returns.
The net return without rain, is nultip.iedby the proba.lLty of no rain, and
the net return with rain is multiplied by the probability of rain. This
20


I









yields the expected net return from irrigation. The expected return from
irrigation is positive with or without rain. IRRIGATE makes the following
recommendation:

Screen 22.
Field-OMRN Rainfall History-EARLY Decision Date- 6 / 10
p increase in profits if you
irrigate today is : $ 3.20/A
The todel recamewnds that you irrigate today
Enter "Y" to change any factors and reevaluate the decision.
Enter "N" to return to the Execution Menu. (Y/N) ->Y

IRRIGATE recommends irrigation and displays the expected increase in
profits. Remember that IRRIGATE assumes sufficient water, fetl izer, and
Spn l ithe future, so this value represents the expected
This recommendation depends on factors. By entering "Y" you an
return to Screen 17 to quickly reevaluate the irrigation decision with
changes in these factors. For example, enter "N" at Screen 17. At Screen
18, change the temperature forecast to "Cooler than Normal" and the cloud
forecast to "Cloudier than Normal" so the "Weather Condition" menu looks

Screen 18.
Field-CON Rainfall History-SAMPLE Decision Date- 6 / 10
WEATHER CONDITIONS
1. Temperature Coole than normal
2. Cloud Cover Cloudier than normal
3. Probable Rain 1.14 inches
4. Rainfall Probability 60 %
Change any of the above?
(Enter 'I or item # above)-> N

Make no changes at Screen 19. Now look at the evaluation:
Screen 21.
Field-CORN Rainfall History-SAMPLE Decision Date- 6 / 10
SUMMARY EVALUATION: No Rain With Rain
2nd Day 2nd Day
from Irrigation 2.72 B./A. 1.34 B./A.
x Crop Price $ 2.75 /B. $ 2.75 /B.

Gross Return 7.48 /A. $ 3.68 A.
Var Irr. Cost 6.97 697
( 1 n./Acre)

Net Retun $40.51 /A. -$ 3.29 /A.
x Probability 40 % 60 %

Expected Return= $ 0.22 /A. -$ 1.93 /A.
PRESS SPACE BAR TO CONTINUE









You can see that irrigation would be profitable only if no rain occurs
for the next three days. IRIGATE's recommendation is:
Screen 22.


When the expected profitability of irrigation is dependent on the
Balla probabitmfiRGATE displays the expected change -nprofits from
irrgaton. This may be positive or negative. IRRIGATE recurends
irrigation if the probability of rainfall is less than a breakeven
percentage th expected profit from irrigation without rain equals the
expected oCsf= f d~oes rain.
Enter "Y" to return to Screen 17 and change the observed days of
visible wilt to "O." Leave the other factors in Screens 17, 18, and]19 as
they are. Now look at the results:
Screen 21.


Field-Corn


SUMMARY EVALUATION:

Yield Difference
from Irrigation
x Crop Price

Gross Return
-Va;. Irr. Cost
(1 in./Acre)

Net Retun
x Probability

Expected Return-
PRESS SPACE BAR TO


Rainfall History-SAMPLE


No Rain
2nd Day


1.39 B./A.
$ 2.75 /B.

S3.82 /A.
-$ 6.97 A.


-$ 3.15 /A.
40 %

-$ 1.26 /A.
CONTINUE


Decision Date- 6 / 10


With Rain
2nd Day


0.54 B./A.
$ 2.75 /B.

$ 1.48 /A.
-$ 6.97 /A.


-$ 5.49 /A.
60 %

-$ 3.29 /A.


In this example, there is not a sufficient increase in eld to cover
the cost of irrigation even if it does not rain. IRIGATE gives the
following tion:
Screen 22.
Field-Corn Rainfall History-SAMPLE Decision Date- 6 / 10
ct decrease in profits if you
rigate today is: $ -4.55
The model recommends that you do not irrigate today
Enter 'Y' to change any factors and reevaluate the decision.
Enter 'N' to return to the Execution Menu. (Y/N) -> N


ion Date- 6 / 10


Field-Corn Rainfall History-SAMPLE Decis:
pted chang e in profits if you
t today is: $ -1.71
he model recomends hat#yov irrigate today
the probability of rainfall Is less than 14%
Enter "Y" to change any factors and reevaluate the decision.
Enter "N" to return to the Execution Menu. (Y/N)-> Y










If IRRIGATE determines that irrigation would not be profitable with or
without ra n, the expected decrease in profits is displayed with a
recommendation not to irrigate.
Obviously, the economic evaluation of an irrigation decision during the
growing season depends on many variables. IGA can hep, you consider
these many factors before you make a final irrigation decision. If you
enter "N" you will return to the Execution Menu to consider another field or
exit the program.









APPENDIX A.
Files on Diskette
By selecting Option ] from the Execution Menu, you can use DOS to
examine the files you copied to your work diskette. At the "A>" prompt,
type "DIR ." The following will be displayed:


The files with the extension "DAT" are data used to calculate the
growt stage dates for the soybean maturity group or corn variety used as
thefile name. The extension "FLD" is used or the field description and
iigat on. history files with the field name as the file name. Rainfall
histories have the extension "WAI." You can use this procedure to view any
field names or rainfall histories you enter later. "BASICA CM" is the file
you copied from the BASIC diskette. ,"IRRIGATE BAS" is the actual program.
"AUTOEXEC BAT" is used to automatically run the pro "CmMMAND CoT" is
the DOS system copied by the FORMAT command. All files except those with
the "FLD" or "RAI" extension are necessary for the diskette to work as
described.
Note: IRRIGATE is saved as an ASCII file. In order to speed up
loading of the program, you may folow these steps:
1. Proceed as described earlier and start the program.
2. Once the Execution Menu appears, ressthe and
keys. A message "Break in 40110" followed by the "OK" prompt will
3. a M VE"IRRIGATE". An "OK" prompt will then appear..
4. PLess the key. If the program does not work as described,
repeat the procedure in "Gettig Started" and ignore this note.


A>DIR
Volume in drive A has no label
Directory of A:\
COMMAND OCM 17792 10-20-83
V DAT 316 1-01-80
VI DAT 316 1-01-80
CORN FLD 79 1-01-80
VII DAT 316 1-01-80
VIII DAT 316 1-01-80
123-DAY DAT 306 1-01-80
115-DAY DAT 306 1-01-80
SAMPLE RAI 2072 1-01-80
130-DAY DAT 306 1-01-80
SOYBEAN FLD 125 1-01-80
IRRIGATE BAS 41604 1-01-80
BASICA COM 26112 10-20-83
AUTOEXEC BAT 17 1-01-80
14 File(s) 239616 bytes
A>


12: 00p
5:17a
5:17a
12:52a
5:17a
5:17a
5:17a
5:17a
12:39a
5:17a
1: 05a
3:15a
12: 00p
12:07a
free










APPENDIX B.
Growth Stage Descriptions for Soybeans
Period Description
0 Plants have not ye emerged
1 : Vegetative growth is coinuing; No flowers
2 : Flowering is occurring; Pods have not yet
beg to set
3 : Ps ae setting; Flowering continues
4 : Flowering has stopped; Pods are filling
5 Pods are yellowing; More than half the leaves
are yellow
Growth Stage Descriptions for Corn
Period Description
0 : Plants have not et emergd.
1 : Vegetative growth s continuing No tassels
2 : Tassels are apearn; No erne development
3 : Tassel ing corplete; sister kernels developing
4 Kernels inmlk or soft-dough stage
5 : Kernels in hard-dough stage; Black layer present









































































COOPERATIVE EXTENSION SERVICE, UNIVERSITY OF FLORIDA, INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES, K.R. Telartler.
director, In cooperation with the United States Department of Agriculture, publishes this information to further the purpose of the May 8 and
June 30, 1914 Acts of Congrees; and is authorized to provide research. educational information and other services only to hniduals and htitu-
tions that function without regard to race, color, a or national origin. Single copies of Extension publications (excluding 4-H and Ybuth publica-
tions) are available free to Florida residents from County Extesion Offices. Information on bulk rames or copies for out-of-state purchasers is
available from C.M. Hinton, Publications Distribution Center, IFAS Building 664, University of Florida, Gainewville. Florida 32611. Beore publiing this publition.
editors should contact this address to determine availability.