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Title: The effects of drip irrigation rates on watermelon yields
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Permanent Link: http://ufdc.ufl.edu/UF00065269/00001
 Material Information
Title: The effects of drip irrigation rates on watermelon yields
Series Title: Bradenton GCREC research report
Physical Description: 9 leaves : ; 28 cm
Language: English
Creator: Clark, Gary A
Maynard, Donald N., 1932-
Gulf Coast Research and Education Center (Bradenton, Fla.)
Publisher: Gulf Coast Research and Education Center
Place of Publication: Bradenton FL
Publication Date: 1994
 Subjects
Subject: Watermelons -- Water requirements -- Florida   ( lcsh )
Microirrigation -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references (leaf 4).
Statement of Responsibility: G.A. Clark and D.N. Maynard.
General Note: Caption title.
General Note: "March 1994."
 Record Information
Bibliographic ID: UF00065269
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 68638896

Table of Contents
    Historic note
        Historic note
    Front Cover
        Front cover
    Main
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
Full Text





HISTORIC NOTE


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not reflect current scientific knowledge
or recommendations. These texts
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Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
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site maintained by the Florida
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Copyright 2005, Board of Trustees, University
of Florida




s-cs
L7-3 l


Gulf Coast Research
and Education Center
_Marston Sc enc
1AY 2 0 1994
S- Udniversity of Florida


5007 60th St. E., Bradenton, Florida 34203-9324








UNIVERSITY OF Gulf Coast Research and
TRTTA Education Center
FRIDA 5007 60th Street East
L Bradenton, FL 34203
Institute of Food and Agricultural Sciences

GCREC Research Report BRA1994-3 (March)

THE EFFECTS OF DRIP IRRIGATION RATES ON WATERMELON YIELDS

G. A. Clark' and D. N. Maynard2

Seasonal water requirements for watermelon vary from 16 to 24 inches. Early in
the season, the water requirement is approximately 40% of potential ET and during
fruit development may exceed 100% of potential ET (Doorenbos and Kassam, 1979;
Ritter et al., 1985).

The effects of drip and overhead irrigation on watermelon yields were compared
at Leesburg and Gainesville (Elmstrom et al., 1981). Early yields were increased
at Leesburg with drip irrigation compared to overhead or no irrigation. Total
yields were greater with irrigation, regardless of source, than with no
irrigation. There was no yield response to irrigation at Gainesville, presumably
because of the higher waterholding capacity of the acid, flatwoods soil used
there. Overall, water use was reduced by about 40% with drip compared to
overhead irrigation.

An identical trial conducted in the spring 1992 season (Maynard and Clark, 1993)
showed that the performance of the five watermelon varieties in the trial with
respect to yield, average fruit weight, soluble solids concentration and presence
and severity of hollowheart was in relation to performance in previous trials
(Maynard, 1992). Total yields were strongly affected by irrigation levels in
four of the five varieties with highest yields occurring at the 2X level which
was equivalent to 7.3 inches for the entire season. For the most part, other
parameters measured in this trial were not affected by irrigation level.

The objectives of this study were to further quantify the effects of three rates
of drip irrigation on watermelon yield, average fruit weight, soluble solids
concentration, and the incidence and severity of hollowheart.

Materials and Methods

Soil samples from the experimental area were obtained before fertilization and
analyzed by the IFAS Extension Soil Testing Laboratory (Hanlon and DeVore,
1989):pH = 7.1 and Mehlich I extractable P = 25, K = 20, Mg = 91, Ca = 612, Zn
= 6.5, Cu = 2.6, and Mn = 3.0 ppm. Soil at the site was EauGallie fine sand.

'Associate Professor of Agricultural Engineering and Extension Irrigation
Specialist.
Professor of Horticultural Sciences and Extension Vegetable Specialist.








The experimental area was prepared in early February 1993 by incorporation of 7
lb 0-20-0 and 6 lb 18-0-25 per 100 linear bed feet (Ibf). This preplant
application provided 52-68-73 lb N-P20-K 0 per acre. Beds were formed and
fumigated with methylbromide:chloropicrin (67:33) at 2.15 lb per 100 Ibf. Drip
irrigation tubing (Roberts Ro-Drip, 12-inch emitter spacing, 0.5 gpm/100 ft
nominal discharge) was installed during bed formation in the bed center
approximately 1-inch below the soil surface. The final polyethylene-mulched beds
were 24-inches wide and 8-inches high and were spaced on 9-ft centers, with four
beds between drainage ditches which were on 41-ft centers.
'Crimson Sweet', 'Jack of Hearts', 'Mickylee', 'Royal Jubilee', and 'Sangria'
watermelon seeds were planted in a peat-lite mix in No. 150 Todd planter flats
on 5 February and the transplants were grown by a commercial plant grower. The
plants were transplanted on 8 March in holes punched in the polyethylene at 3 ft
in-row spacing. Extensive plant loss occurred in the 'storm of the century' on
13-14 March which necessitated considerable resetting of transplants during the
following week. The 36-ft long plots had 12 plants each and were replicated four
times in a randomized complete block design.
All plots were drip irrigated for 30 minutes per day (725 gal/acre/day) for 21
days for crop establishment. This run time was sufficient to allow applied water
to move from the dripper to the transplant location. For the remainder of the
season, scheduled applications were based on ratios of calculated Penman
reference evapotranspiration (ETo) (Burman et al., 1980) using atmospheric data
collected at a weather station approximately 50 feet from the experimental plots.
Calculated Penman ETo data, irrigation Level 1 target application ratio, and
applied irrigation amounts for Levels 1, 2, and 3, are shown in Table 1. Drip
irrigation applications for Levels 2 and 3 were planned to be approximately 2 and
3 times the Level 1 application amount. A faulty valve resulted in 3.7 inches
of water being applied to Level 2 plot in week 5 when only 0.2 inches should have
been applied. This may have caused leaching of granular fertilizer from these
plots. Seasonal applied irrigation amounts totaled 3.2, 9.2 (including excess
water applied in week 5), and 8.4 inches for the Level 1, 2, and 3 treatments,
respectively. Additional fertilizer was applied through the drip system to
provide 95-0-95 lb N-P20s-K20 per acre. Total fertilizer application was 147-68-
168 lb N-P2O0-K20 per acre. Watermelon fruit were harvested on 3, 9, and 18
June. Some fruit in most plots were damaged from feeding by racoons. If the
fruit was marketable in other respects, the average weight of fruit in that plot
at that harvest date was assigned to the damaged fruit for estimation of yield.
Marketable melons (U.S. No. 1 or better) according to U.S. grades (U.S. Standards
for Grades of Watermelons, 1978) were separated from culls and counted and
weighed individually. Soluble solids determinations were made with a hand-held
refractometer on two fruit from each replicate of the 12 treatments on every
harvest date when that variety was harvested, and the incidence and severity of
hollowheart were recorded for these fruits. The resulting data were subjected
to an analysis of variance and mean separation of variety data was by Duncan's
multiple range test. Regression analysis was used for separation of irrigation
rate data.









Results and Discussion

February, March, April, and May of 1993 were slightly cooler than the 39-year
average (Stanley, 1993) while June was somewhat warmer (Table 2). Except for
April, rainfall in the spring of 1993 was less than for the 39-year average.
Aside from the 'storm of the century' on 13-14 March which caused extensive plant
loss, there were no serious adverse weather effects on the watermelon crop.

Early yields ranged from 0 for 'Royal Jubilee' to 169 cwt/acre for 'Sangria'
(Table 3). Early yield of 'Mickylee' was similar to that of 'Sangria'. Average
fruit weight ranged from 14.0 lb for 'Mickylee' to 22.5 lb for 'Crimson Sweet'.
Soluble solids ranged from 11.4% in 'Crimson Sweet' and 'Mickylee' to 11.8% in
'Sangria', exceeding the 10% specified for optional use in the U.S. grades (U.S.
Standards for Grades of Watermelons, 1978). The incidence of hollowheart varied
from 22% for 'Sangria' to 78% for 'Jack of Hearts'. The severity of hollowheart
was greatest in 'Jack of Hearts' with 0.62 inch wide fruit cracks.

Total yields ranged from 461 cwt/acre for 'Jack of Hearts' to 612 cwt/acre for
'Royal Jubilee' (Table 3). Average fruit weight for the entire season, ranged
from 11.5 lb for 'Mickylee' to 24.4 lb for 'Royal Jubilee'. Soluble solids of
all varieties exceeded the optional requirement of 10% specified in the U.S.
grades (U.S. Standards for Grades of Watermelons, 1978). The incidence and
severity of hollowheart was highest in 'Jack of Hearts'.

The fruit weight distribution (Table 4) of the varieties included in this trial
are related closely to average fruit weight (Table 3). Fruit weights are
consistent with the inherent qualities of these varieties, i.e. 'Royal Jubilee'
> 'Crimson Sweet' > 'Sangria' > 'Jack of Hearts' > 'Mickylee'.

Significant quadratic responses to irrigation level occurred for total yield of
'Crimson Sweet', 'Jack of Hearts', 'Royal Jubilee' and 'Sangria' but not for
'Mickylee' (Table 5). However, excess water applied to Level 2 plots in week 5
may have leached granular fertilizer from the bed causing subsequent adverse
effects on growth and development. Average fruit weight (Table 6), incidence
of hollowheart (Table 7), and severity of hollowheart (Table 8) were not affected
by irrigation level. A significant quadratic response for soluble solids of
early harvested 'Crimson Sweet' and 'Mickylee' occurred (Table 9).

The five watermelon varieties included in this trial performed as expected in
respect to yield, average fruit weight, soluble solids concentration, and
incidence and severity of hollowheart. Of the parameters assessed in this trial,
only total yields were significantly affected by irrigation level. In three
varieties 'Crimson Sweet', 'Jack of Hearts', and 'Sangria', highest yields
occurred at irrigation Level 1. On the other hand, highest yields of 'Royal
Jubilee' occurred at irrigation Level 3. Performance of watermelons grown at
irrigation Level 2 may have been adversely affected by the excessive water
application in week 5. By way of comparison, the highest total yields of four
of the five varieties occurred at irrigation Level 2 in the spring 1992 trial
(Maynard and Clark, 1993).








NOTE

The information contained in this report is a summary of experimental results and
should not be used as recommendations for crop production or water allocations.
Where trade names are used, no discrimination is intended and no endorsement is
implied.

LITERATURE CITED


Burman, R. D., P. R. Nixon, J. L. Wright, and
requirements (Chapter 6) in: M. E. Jensen
farm irrigation systems, Monograph No.
Agricultural Engineers, St. Joseph, MI.


W. 0. Pruitt.
(ed.) Design and
3. American


1980. Water
operation of
Society of


Doorenbos, J. and A. H. Kassam. 1979. Yield response to water. FAO Irrig.
Drain. Paper 33. FAO, Rome.


Elmstrom, G. W., S. J. Locascio, and J. M. Myers.
drip and sprinkler irrigation. Proc. Fla.


1981. Watermelon response to
State Hort. Soc. 94:161-163.


Hanlon, E. A. and J. M. DeVore. 1989. IFAS extension soil testing laboratory
chemical procedures and training manual. Fla. Coop. Ext. Circ. 812.


Maynard, D. N. (ed.) 1992.
Fla. Agr. Expt. Sta.


Maynard, D. N.
yields.


Vegetable variety trial results in Florida for 1991.
Circ. S-384.


and G. A. Clark. 1993. Drip irrigation rates affect watermelon
GCREC Res. Rept. BRA1993-4.


Ritter, W. F., T. H. Williams, and R. W. Scarborough.
for corn, soybeans, and vegetables in Delaware.
463.


1985. Water requirements
Del. Agr. Expt. Sta. Bul.


Stanley, C. D. 1993. Weather report for 1992. GCREC Res. Rept. BRA1993-1.
U.S. Standards for Grades of Watermelons. 1978. U.S.D.A., Washington, DC.








Table 1. Irrigation treatment Level 1 application ratios, and average daily
levels of calculated Penman ETo and applied drip irrigation amounts
for irrigation levels 1, 2, and 3. Spring 1993.

Weeks of Application Penman ETo Level 1 Level 2 Level 3
season ratio ---------------- qal/acre/day -----------------

4 0.08 3750 280 700 670
5 & 6 0.10 4490 440 680' 1160
7 & 8 0.11 4815 510 1010 1400
9 & 10 0.19 5140 980 2000 3000
11 & 12 0.23 5350 1240 2540 3730
13 & 14 0.22 5350 1190 2400 3630


'Plots receiving irrigation Level 2 received approximately 100,000 gallons per
acre during week 5 due to a faulty valve.






Table 2. Temperature and rainfall at the Gulf Coast Research and Education
Center from 8 March to 18 June 1993 and 39-year monthly averages
(Stanley, 1993).

Average Temperature (oF)
1993 39-year average Rainfall (in.)
Month (date)' Max. Min. Max. Min. 1993 39-year average

March (8-31) 76 55 77 55 1.46 3.40
April 80 57 82 60 4.33 1.68
May 86 64 87 64 1.53 3.16
June (1-18) 93 70 89 70 0.83 7.97

11993 data are for the dates shown; 39-year averages are for the entire month.








Table 3. Yield, average fruit weight, soluble solids, and the incidence and
severity of hollowheart of five watermelon varieties averaged over
three drip irrigation rates. Gulf Coast Research and Education
Center. Spring 1993.

Early Harvest1
Hollow-3
Avg. Soluble Hollow- heart
Weight fruit solids heart avg.
Variety (cwt/A)2 wt (Ib) (%) (%) (in)

Royal Jubilee NM4 -
Crimson Sweet 100 b 22.5 a 11.4 a 57 a 0.32 b
Sangria 169 a 22.1 a 11.8 a 22 bc 0.28 b
Mickylee 136 ab 14.0 b 11.4 a 33 b 0.24 b
Jack of Hearts 100 b 14.5 b 11.5 a 78 a 0.62 a
Total Harvest

Royal Jubilee 612 a 24.4 a 11.3 ab 28 b 0.30 b
Crimson Sweet 510 b 19.8 b 11.2 b 35 b 0.24 b
Sangria 491 b 19.8 b 11.6 a 24 b 0.24 b
Mickylee 472 b 11.5 c 11.4 ab 33 b 0.19 b
Jack of Hearts 461 b 13.4 c 11.8 a 72 a 0.55 a

'Harvested 3 June.
2Acre = 4840 Ibf.
3Average width of fruit cracks of fruit with hollowheart.
SNot mature.
5Mean separation in columns within harvests by Duncan's multiple range test,
5% level.

Table 4. Fruit weight distribution of the total harvest of five watermelon
varieties averaged over three drip irrigation rates. Gulf Coast
Research and Education Center. Spring 1993.

Fruit Weight (Ib)
<5.0 5.1-10.0 10.1-15.0 15.1-20.0 20.1-25.0 >25
Variety Percentage of fruit

Crimson Sweet 0 b 3 c 21 c 35 a 22 b 19 b
Jack of Hearts 0 b 15 b 58 a 24 ab 3 c 0 c
Mickylee 4 a 41 a 36 b 14 b 4 c 1 c
Royal Jubilee 0 b 0 c 4 d 17 b 34 a 45 a
Sangria 0 b 3 c 15 c 36 a 30 ab 16 b

iMean separation in columns by Duncan's multiple range test, 5% level.









Table 5. Early and total yields of
levels of drip irrigation.
Spring 1993.


five watermelon varieties grown at three
Gulf Coast Research and Education Center.


Irrigation Level
Variety 1 2 3 Response'
Early Harvest -------------(cwt/A) --------------

Crimson Sweet 110 105 84 NS
Jack of Hearts 93 113 94 NS
Mickylee 130 156 122 NS
Royal Jubilee NM3 NM NM
Sangria 186 179 141 NS
Total Harvest
Crimson Sweet 675 407 449 Q*
Jack of Hearts 543 397 444 Q*
Mickylee 580 405 433 NS
Royal Jubilee 652 472 711 Q**
Sangria 594 380 500 Q**


'Harvested 3 June.
Acre = 4840 Ibf.
3Not mature.
4NS = not significant,
quadratic response at


Q* = quadratic response
1% probability level.


at 5% probability level, Q** =


Table 6. Average fruit weight of five watermelon varieties grown at three
levels of drip irrigation. Gulf Coast Research and Education Center.
Spring 1993.

Irrigation Level
Variety 1 2 3 Response3
Early Harvest' ----------------(b)-----------------

Crimson Sweet 20.0 22.4 25.1 NS
Jack of Hearts 14.2 14.5 14.7 NS
Mickylee 13 2 14.6 14.2 NS
Royal Jubilee NM NM NM
Sangria 23.2 21.9 21.3 NS

Total Harvest
Crimson Sweet 21.5 18.1 19.7 NS
Jack of Hearts 14.1 12.6 13.4 NS
Mickylee 12.4 10.8 11.5 NS
Royal Jubilee 26.4 23.1 23.6 NS
Sangria 19.2 19.8 20.4 NS


'Harvested 3 June.
2Not mature.
NS = not significant.









Table 7. Incidence of hollowheart of five watermelon varieties grown at three
levels of drip irrigation. Gulf Coast Research and Education Center.
Spring 1993.

Irrigation Level
Variety 1 2 3 Response
Early Harvesti -----------------(%)---------------

Crimson Sweet 28 63 80 NS
Jack of Hearts 62 85 88 NS
Mickylee 40 33 25 NS
Royal Jubilee NM2 NM NM
Sangria 25 30 10 NS

Total Harvest
Crimson Sweet 25 48 34 NS
Jack of Hearts 69 78 68 NS
Mickylee 43 32 24 NS
Royal Jubilee 33 30 20 NS
Sangria 18 34 19 NS

'Harvested 3 June.
2Not mature.
3NS = not significant.


Table 8. Severity of hollowheart of five watermelon varieties grown at three
levels of drip irrigation. Gulf Coast Research and Education Center.
Spring 1993.

Irrigation Level
Variety 1 2 3 Response
Early Harvest' ----------------(in.) --------------

Crimson Sweet 0.42 0.23 0.31 NS
Jack of Hearts 0.55 0.51 0.81 NS
Mickylee 0.0? 0.24 0.37 NS
Royal Jubilee NM NM NM
Sangria 0.04 0.32 0.47 NS

Total Harvest
Crimson Sweet 0.25 0.16 0.31 NS
Jack of Hearts 0.53 0.50 0.63 NS
Mickylee 0.20 0.19 0.19 NS
Royal Jubilee 0.28 0.33 0.28 NS
Sangria 0.28 0.19 0.26 NS

'Harvested 3 June.
2Not mature.
3Average width of fruit cracks of fruit with hollowheart.
4NS = not significant.









Table 9. Soluble solids of five watermelon varieties grown at three
drip irrigation. Gulf Coast Research and Education Center.
1993.


levels of
Spring


Irrigation Level
Variety 1 2 3 Response
Early Harvest' ------------------(%)---------------

Crimson Sweet 11.0 10.7 12.5 Q*
Jack of Hearts 11.7 11.2 11.6 NS
Mickylee 11. 10.7 11.5 Q**
Royal Jubilee NM NM NM --
Sangria 12.1 11.6 11.7 NS

Total Harvest
Crimson Sweet 11.3 10.9 11.3 NS
Jack of Hearts 11.9 11.7 11.7 NS
Mickylee 11.7 11.1 11.5 NS
Royal Jubilee 11.4 11.3 11.2 NS
Sangria 11.6 11.3 12.0 NS

'Harvested 3 June.
2Not mature.
NS = not significant, Q* = quadratic response at 5% probability level, Q** =
quadratic response at 1% probability level.







The Gulf Coast Research and Education Center


The Gulf Coast Research and Education Center is
a unit of the Institute of Food and Agricultural Sci-
ences, University of Florida. The Research Center
originated in the fall of 1925 as the Tomato
Disease Laboratory with the primary objective of
developing control procedures for an epidemic out-
break of nailhead spot of tomato. Research was ex-
panded in subsequent years to include study of sev-
eral other tomato diseases.

In 1937, new research facilities were established
in the town of Manatee, and the Center scope was
enlarged to include horticultural, entomological, and
soil science studies of several vegetable crops. The
ornamental program was a natural addition to the
Center's responsibilities because of the emerging in-
dustry in the area in the early 1940's.

The Center's current location was established in
1965 where a comprehensive research and extension
program on vegetable crops and ornamental plants is
conducted. Three state extension specialists posi-
tions, 16 state research scientists, and two grant
supported scientists from various disciplines of
training participate in all phases of vegetable and
ornamental horticultural programs. This interdisci-
plinary team approach, combining several research
disciplines and a wide range of industry and faculty
contacts, often is more productive than could be ac-
complished with limited investments in independent
programs.


The Center's primary mission is to develop new
and expand existing knowledge and technology, and
to disseminate new scientific knowledge in Florida, so
that agriculture remains efficient and economically
sound.

The secondary mission of the Center is to assist
the Cooperative Extension Service, IFAS campus
departments, in which Center faculty hold appropri-
ate liaison appointments, and other research centers
in extension, educational training, and cooperative
research programs for the benefit of Florida's pro-
ducers, students, and citizens.

Program areas of emphasis include: (1) genetics,
breeding, and variety development and evaluation;
(2) biological, chemical, and mechanical pest manage-
ment in entomology, plant pathology, nematology,
bacteriology, virology, and weed science; (3) produc-
tion efficiency, culture, management, and counteract-
ing environmental stress; (4) water management and
natural resource protection; (5) post-harvest physiol-
ogy, harvesting, handling and food quality of horti-
cultural crops; (6) technical support and assistance to
the Florida Cooperative Extension Service; and (7)
advancement offundamental knowledge ofdisciplines
represented by faculty and (8) directing graduate
student training and teaching special undergraduate
classes.


Location of
GCREC Bradenton


IFAS IS:
" The Institute of Food and Agricultural Sciences,
University of Florida.
" A statewide organization dedicated to teaching,
research and extension.
J Faculty located in Gainesville and at 13 research
and education centers, 67 county extension
offices and four demonstration units throughout
the state.
O A partnership in food and agriculture, and natural
and renewable resource research and education,
funded by state, federal and local government,
and by gifts and grants from individuals, founda-
tions, government and industry.
IJ An organization whose mission is:
Educating students in the food, agricultural,
and related sciences and natural resources.
Strengthening Florida's diverse food and
agricultural industry and its environment
through research.
Enhancing for all Floridians, the application
of research and knowledge to improve the
quality of life statewide through IFAS exten-
sion programs.




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