|
F rI
W
February 1987
Floppy disc included with this
item has been shelved separately.
consult LUIS or ask circulation
staff for assistance.
Circular 742
Sugarcane Replanting Strategy Analysis
To Minimize Damage from New Pests
Central Science
Library
JAN 30 1990
University of Florida
I COMPUTER SERIES
Jose Alvarez and Barry Glaz
101 c t Extension Service / Intitute o Food and Agricultural Sleness / Univerity of Florid / John T. Woese, Dean
F636c
74?
guide
Trade names are used liberally in this document. Their mention is for illustrative purposes only and does not reflect any
preference, support, or relationship by or to the authors, The University of Florida, The Cooperative Extension Service,
and the U.S. Department of Agriculture, in any explicit or implicit manner.
SUGARCANE REPLANTING STRATEGY ANALYSIS
TO MINIMIZE DAMAGE FROM NEW PESTS
(C) 1986, IFAS, UF
Jose Alvarez and Barry Glaz
FOOD AND RESOURCE ECONOMICS DEPARTMENT
INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES
FLORIDA COOPERATIVE EXTENSION SERVICE
UNIVERSITY OF FLORIDA
AND
SUGARCANE FIELD STATION
UNITED STATES DEPARTMENT OF AGRICULTURE
ARS, SAA, CANAL POINT, FLORIDA
UNIVERSITY OF FLOID BRARI
ABSTRACT
This manual explains how to use the "Sugarcane Replanting
Strategy Analysis to Minimize Damage From New Pests"
microcomputer program. The objective of this software is to
present a general framework for evaluating alternative replanting
strategies by using variables such as average yield of the four
most widely used cultivars over a three year cycle, year in which
pest arrives, damage caused to susceptible cultivars and land
distribution among the cultivars. After completing the analysis,
input variables can be changed to determine their effect on the
total yield over a 20-year period and on the
yield/acre/year/crop. Although the program was developed for
Florida producers and uses the concept of "standard ton" as the
yield measure, it can be used in other areas by inputing yield
on a relative percentage basis or by using net tons or other
unit.
Keywords: Saccharum spp., sugarcane cultivar, microcomputer
IBM PC is a trademark of International Business Machines Corp.
TABLE OF CONTENTS
Page
INTRODUCTION . . .
HARDWARE REQUIREMENTS. .
GETTING STARTED. . .
RUNNING THE PROGRAM. .
PROGRAM FLEXIBILITY. .
ORDERING INFORMATION .
REFERENCES . . . .
APPENDIX: METHODOLOGY. .
. . . . . . . . . 6
. . . . . . . . . 6
. . . . . . . . . 8
. . . . . . . . . 16
. . . . . . . . . 17
. . . . . . . . . 17
. . . . . . . . . 18
SUGARCANE REPLANTING STRATEGY ANALYSIS
TO MINIMIZE DAMAGE FROM NEW PESTS
Jose Alvarez and Barry Glaz
(C) 1986, IFAS, UF
INTRODUCTION
Sugarcane producers throughout the world face the decision
of how to allocate their land among the different available
cultivars. The problem is aggravated by the fact that, in most
producing areas, there are only one, or perhaps two, outstanding
cultivars. Threats of new pests, or new races or strains of
previously existing pests, make producers reluctant to rely
exclusively on any one outstanding cultivar.
Florida producers are no exception. The relatively recent
experience with rust and smut, where a large percentage of the
commercial cultivars and clones in the early stage of a breeding
program were found to be susceptible to these pests, reinforces
producers' attitudes toward risk by relying on several cultivars
to minimize economic losses.
Growers' perceptions, however, seem to be unfounded. In a
recent article, Glaz et al. (1986) show that, under conditions
they considered normal, the most productive option was to grow the
highest yielding cultivar on 88% of the available land.
------------------ ----------------------------
Jose Alvarez is Area Economist, Food and Resource Economics
Department, University of Florida, Everglades Research and
Education Center, Belle Glade, FL. Barry Glaz is Agronomist,
USDA, Sugarcane Field Station, Canal Point, FL.
4
The objective of this Circular is to demonstrate a
microcomputer program. Sugarcane producers can use the program to
determine how to allocate their available land among different
cultivars when considering potential yield reductions from pests.
Although the mathematical model is fully described in the
Appendix at the end of this Circular, its basic assumptions and
constraints are now briefly explained:
1. The practice of successive planting (replanting soon after
harvesting) is always carried out with no land in fallow during
a 20-year planning horizon.
2. All seed cane is obtained from the plant-cane crop with
one acre of sugarcane used as seed planting 12.5 acres.
3. Four cultivars (two assumed to be resistant and two
assumed to be susceptible to new pests) are used on 300 acres of
land divided among the plant-cane crop and two ratoon crops.
The combined acreage of each pair of cultivars must be equal to
or greater than 0.64 acres.
4. Of the 100 acres in the plant crop, 92 acres are
harvested and 8 acres are used as seed cane.
5. After the arrival of the pest, between years 1 and 17,
replanting is carried out with seed from resistant cultivars
first, continuing with seed from susceptible cultivars if
necessary. No land is left unplanted, even if it must be
planted with seed cane of susceptible cultivars.
Although the program was developed for Florida producers and
uses the concept of "standard ton" as the yield measure, it can be
useful in other sugarcane producing areas by inputing yield on a
5
relative percentage basis or by using net tons or other yield
units.
HARDWARE REQUIREMENTS
The computerized "Sugarcane Replanting Strategy Analysis to
Minimize Damage From New Pests" program consists of this user's
manual and a distribution disk. To use this program, an IBM
Personal Computer, or compatible, with a minimum configuration of
64 Kilobytes of RAM and one disk drive is required. If printed
reports are desired, a printer is also needed.
GETTING STARTED
Before running the program for the first time, the user
should make a back-up copy of the distribution disk and store it
in a safe location. The instructions for duplicating diskettes
can be found in the operating system's manual of your
microcomputer.
The distribution disk contains one BASIC file called
CULTIVAR.BAS. To start a session with one disk drive, you must
first load BASIC by booting the DOS disk and after the A> prompt
typing BASIC and pressing the key. After the Ok prompt,
remove the DOS disk and replace it with the distribution disk,
type LOAD"CULTIVAR and press the key. Then type RUN or
simply press the (F2} key and the title screen will.show up on
the screen. In the case of two disk drives, boot the DOS disk in
drive A with the distribution disk in drive B and type BASIC
after the A> prompt and then . After the Ok prompt, type
6
LOAD"B:CULTIVAR and press the key. Then type RUN or press
the {F2} key. If your DOS disk does not have BASIC on it,
consult your BASIC manual to load it and then follow the
instructions to load CULTIVAR after the Ok prompt.
Some users may want to create a system disk that has BASIC
and the program file on it to avoid disk swapping. In addition,
creating an AUTOEXEC file will make the program easier to use.
To create an AUTOEXEC file, and thus a disk that will
automatically load the program, follow these instructions:
1. Create a disk with DOS and BASIC on it by following the
instructions in your operating system's manual.
2. Place the original distribution disk in drive A and the
new system disk in drive B.
3. From the A> prompt type: COPY *.BAS B:
4. Remove the original distribution disk and store it in a
safe location as a back-up copy. Place the new system
disk, which now contains the BASIC program file, in drive
A.
5. From the A> prompt type: COPY CON: AUTOEXEC.BAT
BASIC CULTIVAR
{F6}
Now when you turn the computer on, or issue the (Alt} {Ctrl}
(Del} reboot sequence on the IBM PC, or compatible, with the new
system disk in drive A, the program will automatically run.
Any screen of information displayed on the monitor can
easily be copied to a printer by pressing the SHIFT {(} {PrtSc}
keys. Since there are no hardcopy functions in the program, using
this method will be helpful for saving a printed copy of the
analyses. If at any point in the program you want to return to
the beginning, press {Ctrl} {Break} and then type RUN"CULTIVAR or
press the {F2} key.
RUNNING THE PROGRAM
The first screen displays the title and version of the
program. It also gives the user two options. The first one shows
the credit and disclaimer screens. Users are encouraged to select
this option when running the program for the first time. To read
this information, answer the MAKE SELECTION question *with the
number 1 and press . The credit screen will be displayed.
By pressing at the end of this screen, the disclaimer
screen will be shown. Pressing again will display the
assumptions of the program with some instructions. Pressing the
key again will take the user to the first input section.
If number 2 is selected from the title screen, the program will go
directly to the screen containing the assumptions and
instructions and then to the first input section.
The figures in the following example run are for
demonstration purposes and are always underlined to show that
they are provided by the user and not the computer. The first
input screen requests yield data for the four most widely used
cultivars:
ENTER THE 3-CROP AVERAGE YIELD DATA:
((PC+lR+2R)/3)
FOR CULTIVAR 'A' BEFORE PEST ARRIVES (STANDARD TONS/ACRE) ? 37
FOR CULTIVAR 'B' BEFORE PEST ARRIVES (STANDARD TONS/ACRE) ? 39
FOR CULTIVAR 'C' BEFORE PEST ARRIVES (STANDARD TONS/ACRE) ? 42
FOR CULTIVAR 'D' BEFORE PEST ARRIVES (STANDARD TONS/ACRE) ? 48
ARE THESE ENTRIES OK (Y/N) ? Y
The last line in the previous screen allows correcting the
information entered when necessary. Typing the letter N takes the
user back to the beginning of that section. If the entries are
correct, typing a Y allows entering data for the next input
section:
ENTER THE FOLLOWING INFORMATION:
YEAR IN WHICH PEST ARRIVES (#) ? 10
DAMAGE PEST CAUSES TO CULTIVARS 'C' AND 'D' (%)
(ENTER AS %. EX: 20, 15.52, ETC.) ? 20
ARE THESE ENTRIES OK (Y/N) ?Y
Finally, the program requests information related to how the
land is allocated among the four cultivars. If the four entries
do not add up to 100, or if the combined acreage of cultivars 'A'
and 'B' and of cultivars 'C' and 'D' are less" than 0.64 acres,
the program will display a message indicating the type of error
made and will give the user the opportunity of entering the
correct data:
ENTER THE FOLLOWING ACREAGE FIGURES:
FIRST RATOON CANE HARVESTED OF CULTIVAR 'A' IN YEAR ONE (# OF ACRES) ? 25
FIRST RATOON CANE HARVESTED OF CULTIVAR 'B' IN YEAR ONE (# OF ACRES) ? 25'
FIRST RATOON CANE HARVESTED OF CULTIVAR 'C' IN YEAR ONE (# OF ACRES) ? 25
FIRST RATOON CANE HARVESTED OF CULTIVAR 'D' IN YEAR ONE (# OF ACRES) ? J
ARE THESE ENTRIES OK (Y/N) ? Y
The computer now has all the information necessary to make
9
the calculations. After pressing the letter Y and the
key, the screen displays the yearly land distribution by
cultivar and crop:
**YEARLY LAND DISTRIBUTION BY CULTIVAR AND CROP**
CULTIVAR A CULTIVAR B CULTIVAR C
PC 1R 2R PC 1R 2R PC IR 2R
23.0 25.0 25.0 23.0 25.0 25.0 23.0 25.0 25.0
DISTRIBUTION REMAINS THE SAME UNTIL PEST ARRIVES
21.0 25.0 25.0 21.0 25.0 25.0 25.0 25.0 25.0
46.0 25.0 25.0 46.0 25.0 25.0 0.0 25.0 25.0
46.0 50.0 25.0 46.0 50.0 25.0 0.0 0.0 25.0
46.0 50.0 50.0 46.0 50.0 50.0 0.0 0.0 0.0
46.0 50.0 50.0 46.0 50.0 50.0 0.0 0.0 0.0
CULTIVAR
PC 1R
23.0 25.0
25.0
0.0
0.0
0.0
0.0
25.0
25.0
0.0
0.0
0.0
LAND DISTRIBUTION REMAINS THE SAME UNTIL YEAR 20
PRESS TO SEE THE RESULTS
Since eight acres of seed are needed, and there are 25 acres
of each cultivar in this example, year 1 shows that only 23 acres
of each cultivar are harvested. When the pest arrives in year 10,
since cultivars 'C' and 'D' are susceptible, their acreages remain
at 25 and all eight acres of seed cane are taken from cultivars
'A' and 'B'. Therefore, only 21 acres of these cultivars are
harvested in year 10. In year 11 the susceptible cultivars, 'C'
and 'D', have been totally phased out in plant cane. Therefore,
all 92 acres harvested from plant cane are derived from
cultivars 'A' and 'B'. First- and second-ratoon cane acreages
remain the same and second-ratoon acreages in year 12 also
YEAR
1
LAND
10
11
12
13
14
D
2R
25.0
25.0
25.0
25.0
0.0
0,0
remain the same. In year 13, cultivars 'C' and 'D' are no longer
being harvested. This distribution continues until the end of the
planning horizon.
-- After pressing the key the results of the analysis
appear on the screen:
**SUGARCANE REPLANTING STRATEGY ANALYSIS**
A. FIRST RATOON CANE HARVESTED OF CULTIVAR 'A' IN YEAR ONE 25 ACRES
FIRST RATOON CANE HARVESTED OF CULTIVAR 'B' IN YEAR ONE 25 ACRES
FIRST RATOON CANE HARVESTED OF CULTIVAR 'C' IN YEAR ONE 25 ACRES
FIRST RATOON CANE HARVESTED OF CULTIVAR 'D' IN YEAR ONE 25 ACRES
B. AVERAGE 3-CROP YIELD OF CULTIVAR 'A' BEFORE PEST 37 ST. TONS/ACRE
C. AVERAGE 3-CROP YIELD OF CULTIVAR 'B' BEFORE PEST 39 ST. TONS/ACRE
D. AVERAGE 3-CROP YIELD OF CULTIVAR 'C' BEFORE PEST 42 ST. TONS/ACRE
E. AVERAGE 3-CROP YIELD OF CULTIVAR 'D' BEFORE PEST 48 ST. TONS/ACRE
F. YEAR IN WHICH PEST ARRIVES 10
G. DAMAGE PEST CAUSES TO CULTIVARS 'C' AND 'D' 20 %
TOTAL YIELD FOR 20 YEARS FOR ALL CULTIVARS 230518 ST. TONS
YIELD/ACRE/YEAR/CROP 39.47 ST. TONS
LETTER TO CHANGE (A-G), R TO RERUN THE PROGRAM, X TO EXIT, OR Z TO END ?
The results show that, with the value of the variables
entered, the producer can expect a total yield of 230,518
standard tons during the 20- year planning horizon and a
yield/acre/year/crop of 39.47 standard tons. The last line on the
screen allows the user to. answer "what if" questions, rerun the
program, exit to DOS or end the program. Since the purpose of the
exercise is to compare different acreage allocations, yield
damages, etc., to arrive at the optimal use of the best available
cultivar(s), the LETTER TO CHANGE option is demonstrated below.
Let us assume that the user wants to consider an increase in
acreage of the best cultivar. To do that, s(he) has to answer A
to the "letter to change" question and then enter the new values
for the four cultivars:
LETTER TO CHANGE (A-G), R TO RERUN THE PROGRAM, X TO EXIT, OR Z TO END ? A
NEW FIRST RATOON CANE HARVESTED OF CULTIVAR 'A' IN YEAR ONE (# OF ACRES) 7 8
NEW FIRST RATOON CANE HARVESTED OF CULTIVAR 'B' IN YEAR ONE (# OF ACRES) ? 8
NEW FIRST RATOON CANE HARVESTED OF CULTIVAR 'C' IN YEAR ONE (# OF ACRES) ? 18
NEW FIRST RATOON CANE HARVESTED OF CULTIVAR 'D' IN YEAR ONE (# OF ACRES) ? 276
A new yearly land distribution appears on the screen:
**YEARLY LAND DISTRIBUTION BY CULTIVAR AND CROP**
CULTIVAR A CULTIVAR B CULTIVAR C
PC 1R 2R PC 1R 2R PC 1R 2R
7.4 8.0 8.0 7.4 8.0 8.0 7.4 8.0 8.0
DISTRIBUTION REMAINS THE SAME UNTIL PEST ARRIVES
4.0 8.0 8.0 4.0 8.0 8.0 8.0 8.0 8.0
46.0 8.0 8.0 46.0 8.0 8.0 0.0 8.0 8.0
46.0 50.0 8.0 46.0 50.0 8.0 0.0 0.0 8.0
46.0 50.0 50.0 46.0 50.0 50.0 0.0 0.0 0.0
46.0 50.0 50.0 46.0 50.0 50.0 0.0 0.0 0.0
CULTIVAR
PC 1R
69.9 76.0
76.0
0.0
0.0
0.0
0.0
76.0
76.0
0.0
0.0
0.0
LAND DISTRIBUTION REMAINS THE SAME UNTIL YEAR 20
PRESS TO SEE THE RESULTS
In year 1, 0.64 acres of cultivars 'A', 'B' and 'C', and 6.08
acres of cultivar 'D' are used as seed cane. (The figures shown on
the screen have been rounded to the nearest 0.1.) When the pest
arrives in year 10, the acreages for the susceptible cultivars 'C'
and 'D' remain at 8 and 76, respectively, while all seed cane is
12
YEAR
1
LAND
10
11
12
13
14
D
2R
76.0
76.0
76.0
76.0
0.0
0.0
provided by cultivars 'A' and 'B'. Thus, only 4 acres of these
cultivars are harvested in year 10. The susceptible cultivars 'C'
and 'D' have been totally phased out in plant cane in year 11,
with cultivars 'A' and 'B' providing all 92 acres of seed cane.
First- and second-ratoon cane acreages remain the same in year 11
as well as second-ratoon cane acreage in year 12. In year 13,
cultivars 'C' and 'D' are no longer harvested and this
distribution continues until the end of the planning horizon.
Changing the acreage in cultivar 'D' to 76, and the rest to 8
acres each, increases total standard tons to 242,705 and the
annual, per acre yield to 41.56 standard tons:
**SUGARCANE REPLANTING STRATEGY ANALYSIS**
A. FIRST RATOON CANE HARVESTED OF CULTIVAR 'A' IN YEAR ONE 8 ACRES
FIRST RATOON CANE HARVESTED OF CULTIVAR 'B' IN YEAR ONE 8 ACRES
FIRST RATOON CANE HARVESTED OF CULTIVAR 'C' IN YEAR ONE 8 ACRES
FIRST RATOON CANE HARVESTED OF CULTIVAR 'D' IN YEAR ONE 76 ACRES
B. AVERAGE 3-CROP YIELD OF CULTIVAR 'A' BEFORE PEST 37 ST. TONS/ACRE
C. AVERAGE 3-CROP YIELD OF CULTIVAR 'B' BEFORE PEST 39 ST. TONS/ACRE
D. AVERAGE 3-CROP YIELD OF CULTIVAR 'C' BEFORE PEST 42 ST. TONS/ACRE
E. AVERAGE 3-CROP YIELD OF CULTIVAR 'D' BEFORE PEST 48 ST. TONS/ACRE
F. YEAR IN WHICH PEST ARRIVES 10
G. DAMAGE PEST CAUSES TO CULTIVARS 'C' AND 'D' 20 %
TOTAL YIELD FOR 20 YEARS FOR ALL CULTIVARS 242705 ST. TONS
YIELD/ACRE/YEAR/CROP 41.56 ST. TONS
LETTER TO CHANGE (A-G), R TO RERUN THE PROGRAM, X TO EXIT, OR Z TO END ?
After increasing the percent damage from 20% to 25%,
the program shows a total yield of 241,509.8 standard tons
and of 41.35 standard tons/acre/year/crop. To avoid repetition,
the screen of this output is not shown.
13
Assume now that the producer wants to check the effect of
using the best cultivar almost exclusively, after changing pest
damage back to 20%. The following output screen shows the results
for 97 acres allocated to cultivar 'D': -
**SUGARCANE REPLANTING STRATEGY ANALYSIS**
A. FIRST RATOON CANE HARVESTED OF CULTIVAR 'A' IN YEAR ONE 1 ACRES
FIRST RATOON CANE HARVESTED OF CULTIVAR 'B' IN YEAR ONE 1 ACRES
FIRST RATOON CANE HARVESTED OF CULTIVAR 'C' IN YEAR ONE 1 ACRES
FIRST RATOON CANE HARVESTED OF CULTIVAR 'D' IN YEAR ONE 97 ACRES
B. AVERAGE 3-CROP YIELD OF CULTIVAR 'A' BEFORE PEST 37 ST. TONS/ACRE
C. AVERAGE 3-CROP YIELD OF CULTIVAR 'B' BEFORE PEST 39 ST. TONS/ACRE
D. AVERAGE 3-CROP YIELD OF CULTIVAR 'C' BEFORE PEST 42 ST. TONS/ACRE
E. AVERAGE 3-CROP YIELD OF CULTIVAR 'D' BEFORE PEST 48 ST. TONS/ACRE
F. YEAR IN WHICH PEST ARRIVES 10
G. DAMAGE PEST CAUSES TO CULTIVARS 'C' AND 'D' 20 %
TOTAL YIELD FOR 20 YEARS FOR ALL CULTIVARS 247800 ST. TONS
YIELD/ACRE/YEAR/CROP 42.43 ST. TONS
LETTER TO CHANGE (A-G), R TO RERUN THE PROGRAM, X TO EXIT, OR Z TO END ?
Total and relative yields increased again. But perhaps the
level of damage caused by the pest has been underestimated. For
that reason, let us consider a 5% increase in the damage caused
by the arrival of the pest. The variable G is typed and 25% is
entered:
LETTER TO CHANGE (A-G), R TO RERUN THE PROGRAM, X TO EXIT, OR Z TO END ? G G
NEW DAMAGE PEST CAUSES TO CULTIVARS 'C' AND 'D' (%. EX: 20, 15.52, ETC.) ? j
After pressing the key, the new results appeal on the
screen once the yearly land distribution has been shown:
**SUGARCANE REPLANTING STRATEGY ANALYSIS**
A. FIRST RATOON CANE HARVESTED OF CULTIVAR 'A' IN YEAR ONE
FIRST RATOON CANE HARVESTED OF CULTIVAR 'B' IN YEAR ONE
FIRST RATOON CANE HARVESTED OF CULTIVAR 'C' IN YEAR ONE
FIRST RATOON CANE HARVESTED OF CULTIVAR 'D' IN YEAR ONE
B. AVERAGE 3-CROP YIELD OF CULTIVAR 'A' BEFORE PEST 37 ST.
C. AVERAGE 3-CROP YIELD OF CULTIVAR 'B' BEFORE PEST 39 ST.
D. AVERAGE 3-CROP YIELD OF CULTIVAR 'C' BEFORE PEST 42 ST.
E. AVERAGE 3-CROP YIELD OF CULTIVAR 'D' BEFORE PEST 48 ST.
F. YEAR IN WHICH PEST ARRIVES 10
G. DAMAGE PEST CAUSES TO CULTIVARS 'C' AND 'DI 25 %
1 ACRES
1 ACRES
1 ACRES
97 ACRES
TONS/ACRE
TONS/ACRE
TONS/ACRE
TONS/ACRE
TOTAL YIELD FOR 20 YEARS FOR ALL CULTIVARS 245865.7 ST. TONS
YIELD/ACRE/YEAR/CROP 42.1 ST. TONS
LETTER TO CHANGE (A-G), R TO RERUN THE PROGRAM, X TO EXIT, OR Z TO END?
The answer shows that, with the new level of damage, the
1-1-1-97 allocation is still a
8-8-8-76 allocation. The last
higher-yielding option than the
exercise involves changing the
arrival of the pest from year 10 to year 7:
LETTER TO CHANGE (A-G), R TO RERUN THE PROGRAM, X TO EXIT, OR Z TO END ? F
NEW YEAR IN WHICH PEST ARRIVES (#) ? 7
Although yields are further reduced, the results indicate
that, with a 25% potential damage in year 7, the best cultivar
should still be relied upon and planted in more than half of the
available land:
The user may
time, until s(he)
the output screen
exiting to DOS or
an END OF PROGRAM
make as many changes as desired, always one at a
is satisfied with the result. The last line of
also gives the option of rerunning the program,
finishing the session. When the latter is done,
message is displayed.
PROGRAM FLEXIBILITY
Although the program is based on several assumptions, which
may seem to be rather restrictive, the user may use different
approaches to accommodate other scenarios. For example:
(a) Different 'loss rates per cultivar can be expressed
indirectly by assigning different original yield levels to the
cultivars.
(b) A different planning horizon can be used by increasing or
decreasing the pest damage proportionally if the user believes
that it is too long or too short, respectively.
16
**SUGARCANE REPLANTING STRATEGY ANALYSIS**
A. FIRST RATOON CANE HARVESTED OF CULTIVAR 'A' IN YEAR ONE 1 ACRES
FIRST RATOON CANE HARVESTED OF CULTIVAR 'B' IN YEAR ONE 1 ACRES
FIRST RATOON CANE HARVESTED OF CULTIVAR 'C' IN YEAR ONE 1 ACRES
FIRST RATOON CANE HARVESTED OF CULTIVAR 'D' IN YEAR ONE 97 ACRES
B. AVERAGE 3-CROP YIELD OF CULTIVAR 'A' BEFORE PEST 37 ST. TONS/ACRE
C. AVERAGE 3-CROP YIELD OF CULTIVAR 'B' BEFORE PEST 39 ST. TONS/ACRE
D. AVERAGE 3-CROP YIELD OF CULTIVAR 'C' BEFORE PEST 42 ST. TONS/ACRE
E. AVERAGE 3-CROP YIELD OF CULTIVAR 'D' BEFORE PEST 48 ST. TONS/ACRE
F. YEAR IN WHICH PEST ARRIVES 7
G. DAMAGE PEST CAUSES TO CULTIVARS 'C' AND 'D' 25 %
TOTAL YIELD FOR 20 YEARS FOR ALL CULTIVARS 237333.4 ST. TONS
YIELD/ACRE/YEAR/CROP 40.64 ST. TONS
LETTER TO CHANGE (A-G), R TO RERUN THE PROGRAM, X TO EXIT, OR Z TO END ?
<___________ ________________________-
ORDERING INFORMATION
For more information on this and other IFAS software, contact
the local county extension office or write to:
IFAS Software Communication and Distribution
G022 McCarty Hall
University of Florida
Gainesville, FL 32611
REFERENCES
Glaz, B., J. Alvarez and J. D. Miller. "Analysis of Cultivar
Use-Options with Sugarcane as Influenced by Threats of New
Pests," Agronomy Journal 78:3 (May-June 1986):503-506.
APPENDIX: METHODOLOGY
A. Introduction
To view the section of the program with the equations that
calculate total yield (in standard tons) for 20 years and
standard tons/acre/year/crop, after loading the program as
described in the "Getting Started" section, type LIST 710-2040
and press . To print out this section of the program, type
LLIST 710-2040 and press .
CULTIVAR uses a number of variables. In general, the
variables are repeated for each cultivar. Those associated with
cultivar A have an A included in their variable label, and those
associated with cultivars B, C, and D have B, C, and D in their
labels, respectively. Data for 4 cultivars must be entered for
CULTIVAR to function properly. After the user inputs the
necessary data, the program calculates the final values for
cultivars A, B, C, and D separately, and sums these values. These
sums are the values printed on the final output screen.
The user is cautioned that all calculations assume that
cultivars A and B are resistant to the new pest (their yields do
not decline) and cultivars C and D have yield losses because they
are susceptible to the new pest. Brief descriptions of the
cultivar A (a resistant cultivar) variables and of the cultivar D
(a susceptible cultivar) variables follow.
B. Description of Variables Defined by the User
1. Y1A = Yield of cultivar A.
2. Y7D = Yield of cultivar D before pest arrives.
3. Z = Year in which pest arrives.
4. FU = Percentage yield loss to cultivars C and D due to
new pest.
5. RA = First-ratoon cane harvested of cultivar A before
pest arrives (acres).
6. SD = First-ratoon cane harvested of cultivar D before
pest arrives (acres).
C. Description of Variables Calculated by CULTIVAR
1. PA = Acres harvested of cultivar A in plant
cane, in
any year before pest arrives.
2. PD = Acres harvested of cultivar
any year before pest arrives.
3. AZ = Acres harvested of cultivar
year = Z.
4. AlZ = Acres harvested of cultivar
year = Z + 1.
5. A2Z = Acres harvested of cultivar
year = Z + 2.
D in plant
A in plant
cane, in
cane in
A in plant cane in
A in plant cane in
6. AEZ = Acres harvested of cultivar A in first- or second-
ratoon cane in year = Z.
7. ARZ2= Acres harvested of cultivar A in first-ratoon
cane in year = Z + 2.
8. ZAR3= Acres harvested of cultivar A in first-ratoon cane
19
in year = Z + 3.
9. DZ = Acres harvested of cultivar D in plant cane in year
= Z.
10. DlZ= Acres harvested of cultivar D in plant cane in year
= Z + 1.
11. D2Z= Acres harvested of cultivar D in plant cane in
year = Z + 2.
12. DR2= Acres harvested of cultivar D in first-ratoon cane
in year = Z + 2.
13.D3ZS= Acres harvested of cultivar D in first-ratoon cane
in year = Z + 3.
Note: Examples of the calculations of the above variables are
shown in "A Calculation Example," or section D of th-is Appendix.
To calculate each of the above 11 variables, it was assumed that
"there are 92 and 100 acres harvested in the plant and two ratoon
crops, respectively, relative cultivar acreages will remain
constant until a new pest arrives, replanting will be carried out
to the fullest extent possible with resistant cultivars" (Glaz et
al., 1986) and all seed cane is from the plant-cane crop.
14. Y8D= Yield of cultivar D after pest arrives.
15. VlA= The number of years before the pest arrives
multiplied by PA.
16. V2A= The number of ratoon crops harvested before the
pest arrives multiplied by the number -of acres in
each of these crops plus AZ and AlZ.
17. V3A= Number of years that A2Z acres of plant cane are
harvested multiplied by A2Z, plus AEZ multiplied
20
by 5 (because there will be 2 first-ratoon and 3
second-ratoon crops with AEZ acres), plus ARZ2
multiplied by 2 (because there will be 1 first-
ratoon and 1 second-ratoon crop with ARZ2 acres).
18. V4A= Number of times that ZAR3 acres will be harvested in
first- or second-ratoon crops multiplied by ZAR3.
'19. WD = Total yield of cultivar D before pest arrives.
20. CD = Total yield of cultivar D after pest arrives plus
total yield of cultivar D before pest arrives.
21. DNR= Total 20-year yield of all 4 cultivars combined.
22.FDNR= Yield/acre/crop/year of all 4 cultivars combined.
D. A Calculation Example
a) The following data, normally supplied by the user, will
be used for this calculation example:
1. Z = 10
2. RA = RB = SC = 5
3. SD = 85
4. FU = 25
5. Y7D= 20
b) Calculations:
1. Y8D= 20*(100-25)/100 = 15 (line 1140 of program).
2. PA = (92/(l+(5/5)+(5/5)+(85/5)))
= 92/(1+1+1+17) = 4.6 (line 1160).
3. PD = (85/5)*4.6 = 78.2 (line 1190).
Note that PA = PB = PC = 4.6 and (4.6 3) + (PD = 78.2) =92,
the number of plant-cane acres harvested each year.
21
4. AZ = ((12.5 (5+5)) 100)/(12.5 ((1+(5/5))))
= 25/25 = 1 (line 1210).
5. DZ = (85/5) CZ
CZ 92/(1+85/5) = 5.1111
DZ = 17*(5.1111) 86.888 (line 1530).
6. A1Z- (S/(l+(5/5)))
S G/12.5
G (((5+5) 156.25)-100) 1462.5
S 1462.5/12.5 = 117 and 117>92, thus S=92
A1Z = (92/2) = 46 (lines 1250-1280).
A2Z = 46 (lines 1310-1350).
7. D1Z = (85/5) ClZ
ClZ = ((92-U)/((1+(85/5)))).
U-K/12.5
K=((156.25*(5+5))-100) = 1462.5
U = 1462.5/12.5 = 117 and 117>92, thus U=92
C1Z=((92-92)/((1+(85/5)))) 0
D1Z=0 (lines 1600-1640).
8. ARZ2=(100/(1+(5/5))) = 50 (line 1440).
9. D2Z- (85/5) C2Z
C2Z = (92-V)/(l+(85/5))
V=L/12.5
L=((1953.125*(5+5))-100) 19431.25
V=19431.25/12.5 = 1554.5 and 1554.5>92, thus V=92
C2Z = (92-92)/(1+17) 0
D2Z=(85/5)*0 0 (lines 1660-1700).
10. ZAR3=ARZ2 (line 1490).
22
11. D3Z5=D2Z (line 1790).
12. VlA=9*(4.6) = 41.4 (line 1820).
13. V2A = (2*(9)*5) + 0 + 46 = 136 (line 1830).
14. V3A = ((18-9)*46) + (5*5) + (2*50) = 539 (line 1840).
15. V4A=(36-((2*10)+1))*50 = 750 (line 1850).
16. WD=20*(((9*78.2))+(2*9*85)) = 44676 (line 1970).
17. CD = 15*(86.888+0+0+(5*85)+(2*0)+(2*0))+44676 = 52354.32
(line 1980).
This publication was produced at a cost of $176.24, or $1.76 per copy, to demonstrate the use of the sugarcane replant-
ing strategy analysis program. 3-100-87
COOPERATIVE EXTENSION SERVICE, UNIVERSITY OF FLORIDA, INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES, K.R. Tefertiller,
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 Congress; and is authorized to provide research, educational information and other services only to individuals and institu-
tions that function without regard to race, color, sex or national origin. Single copies of Extension publications (excluding 4-1 and Youth publica-
tlons) are available free to. Florida residents from County Extension Offices. Information on bulk rates or copies for out-of-state purchasers is
available from C.M. Hinton, Publications Distribution Center, IFAS Building 664, University of Florida, Gainesville, Florida 32611. Before publicizing this publication,
editors should contact this address to determine availability.
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