Cooperative Extension
Statewide
1997 Cotton Management Economic Notes
The University of Arizona • College of Agriculture • Tucson, Arizona, 85721
Department of Agricultural and Resource Economics
August 12, 1997
the season." This date averaged
August 18 by the calendar for the
data shown.
Russell Tronstad
Extension Economist
Updated Irrigation Termination
The observed range in yield
increase or decrease is very dramatic.
In 1994, a Buckeye location experienced a 383 lb. yield increase by extending the
season 24 days while another 1995 study observed a 232 lb. yield decline. The simple linear
The decision of when to initiate irrigation
termination for Upland cotton continues to be
debated. Wide variations in yield changes from
one season to the next, new technologies, uncertain lint prices, and changes in lint quality from
"extending the season" make
Upland
the irrigation termination decision difficult.
400
Additional Yield. The figure
to the right shows additional
lint yield obtained from extending the season beyond initial
termination dates. Data was
obtained from experiments in
Central Arizona led by
Silvertooth and Husman. Upland varieties evaluated are
relatively indeterminate in nature. Timing for the first irrigation termination plot was targeted for approximately three
weeks after the onset of cutout or when the number of
nodes above the top, first position white bloom (NAWB) become less than 5. Days beyond this first termination date
are referred to as "extending
Recent Prices
94-2
96-4
350
Linear Curve
Fit with 1993
Data Excluded
300
250
70.29
74.79
74.78
74.50
67.32
91-1
96-2
92-1
200
96-3 89-1
150
92-1
91-1
94-2
100
50
93-3
0
-50
95-2 90-1 95-2
96-2
92-1
95-2 95-2
95-1
91-1
90-1
90-1
89-1
95-3
94-3
Legend
Year - Location
1:
2:
3:
4:
93-3
-150
93-3
95-4
93-3
-250
0
5
90-1
91-1 91-1
94-4
93-3
-200
95-1
91-1
92-1
93-3
93-3
-100
10
15
20
25
30
Maricopa Ag Center
Buckeye, site a
Buckeye, site b
Other Central AZ
35
40
45
Days Beyond First Termination Date
varieties were predominantly DPL 5415,DPL 90, NuCotton 33, HS 44, and other
*Upland
indeterminate varieties. The initial termination date was targeted for 3 weeks after the onset of cutout
and averaged August 18.
August 12 1997
Upland Pima (ELS)
(¢/lb)
Spot - uncompressed
Oct '97 Futures
Dec '97 Futures
Dec '98 Futures
Adj. World Price
Irrigation Termination Data* by
Year and Location
Yield Change (lbs./acre)
(¢/lb)
104.50
Note: Upland Spot for Desert SW grade 31-3, staple 35, add 300 points for
compressed bales, Pima Spot for DSW grade 03, staple 46.
curve fit above gives an estimate of what the
yield response is from extending the season.
The estimated line shown above does not include yield responses for 1993. That is, insect
pressures and other conditions for 1993 are
treated as out of the norm. The estimated fit also
gives equal weight to all remaining years rather
than equal weight to each plot or point of data.
After an initial 80lb. yield increase around day 10,
estimated yield increases at 3.0 lbs./day. More
flexible functional forms estimate a yield increase
plateau of around 145 to 150 lbs. 35 days beyond
Issued in furtherance of Cooperative Extension work, acts of May 8 and June 30, 1914, in cooperation with the U. S. Department of Agriculture, James A. Christenson,
Director, Cooperative Extension, College of Agriculture, The University of Arizona.
The University of Arizona College of Agriculture is an equal opportunity employer authorized to provide research, educational information and other services only to
individuals and institutions that function without regard to sex, race, religion, color, national origin, age, Vietnam Era Veteran's status, or disability.
Quality. Extending the season has
been known to reduce the number of
immature fibers and improve quality,
Increase in Production Costs* ($/acre)
$200
but extending the season also risks
$185
deteriorating quality with adverse
$170
weather and insect pressures. Lint
$155
quality changes have a dramatic imMaybe
$140
pact on profit since both the "base
Profitable
$125
yield" and additional yield are affected.
Unprofitable
Using a base yield of 1,200 lbs./acre,
$110
80 75 70 65
the figure in the lower right corner
$95
60
cents/lb.
gives the additional yield required to
$80
justify extending the season for a range
$65
of lint quality changes from -3¢/lb. to
Profitable
$50
+2¢/lb. A higher base yield would
$35
increase (decrease) the amount of
$20
additional lint required to break-even
$5
with a degradation (enhancement) in
5
35
65
95
125
155
185
215
245
275
305
335
365
lint quality. As highlighted with the
Additional Yield (lbs. lint per acre)
dashed lines below, the $80 cost
*Additional costs for ginning, harvest, and opportunity cost of money are accounted for in the figure.
Production Cost increases include water, insecticide, defoliation, and other growing costs.
increase illustrated earlier requires
188 lbs. instead of 146 lbs. to breakthe first termination date. But is this yield increase even with a 2¢/lb. quality degradation. That is,
profitable with higher production, harvest, gin- more than 188 lbs. of additional lint are required
before extending the season becomes profitable
ning, and other costs?
with a 2¢/lb. degradation in lint quality.
Production Costs. Extending the season will
increase the cost of insecticide applications, wa- Risk Return Assessment. The decision of when
ter, defoliation, and possibly other production to terminate also depends on other factors, includcosts. For illustration, say that two additional ing the amount of risk you are able and willing to
insecticide applications at $15/acre, two addi- take on. If your economics for extending the
tional irrigations at $19/acre, and increased defo- season look promising, a wise strategy may be to
liation costs of $12/acre are required. The figure diversify by extending the season on part of your
above indicates that for this $80/acre increase in acreage while terminating the rest.
production cost it would take
Yield Increases Needed to Justify Extending the Season with 70¢
146 lbs. of lint to just break-even
Cotton for Different Cost Increases and Changes in Lint Quality
from extending the season with
Increase in Production Costs* ($/acre)
70¢ cotton. These cost esti250
lbs. acre
300 lbs. acre
lbs./acre
mates may differ substantially $140
lbs./acre
even within a county due to dif- $125
200 lbs. acre
ferent water sources and insect
lbs./acre
lbs./acre
pressures.
$110
Lint Price (¢/lb.) Required to Justify "Extending
the Season" for Different Cost Increases*
250 lbs. acre
Harvest, Ginning and Finance.
Harvest, hauling, and ginning
costs are accounted for in the
above figure at $.20/lb. Additional cottonseed is assumed to
yield 160% of additional lint yields
with a value of $.05/lb. Extending the season also means that
the crop will be sold at a later
date, increasing finance
charges. Funds are charged at
an annual rate of 10% with a
base yield of 1,200 lbs., amounting to $4.83/acre for 21 days.
150 lbs. acre
$95
$80
lbs./acre
200
100 lbs. acre
$65
$50
150
50
$35
100
$20
0
$5
$-0.03
50
$-0.02
$-0.01
$0.00
$0.01
$0.02
Change in Lint Quality ($/lb.)
* Additional costs for ginning, harvest, and opportunity cost of money are accounted for in the figure.
Increase
in production costs are for water, insecticide, defoliation, and other growing costs.
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