Everglades Experiment Station
Belle Glade, Florida
Mimeographed Report No. 16
(Chemistry and Soils)
*?;-
FERTILIZER EXPERIMENTS WITH TOMATOES, SQUASH AND OTHER VEGETABLE CROPS
ON SUNNILAND FINE SAND OF THE INDIANTGWN AREA
W. T. Forsee, Jr., and James C. Hoffman
June 30, 1948
T:Vrtilizer Experiments with Tomatoes and Other Vegetable Crops on the Sandy Soils of
the Florida Lower East Coast Area, 1948.
W. T. Forsee, Jr., and James C. Hoffman
I Introduction
The experiments reported here are a continuation of the work reported last
year in the mimeographed report, "A Preliminary Study of Tomato and Other Vegetable
Crop Problems in the Ft. Pierce Stuart Area". The area chosen for these experiments
was a ten acre plot about two miles southeast of Indiantown, Martin County, Florida.
The field had been previously planted to tomatoes (2 crops), green beans (2 crops),
and squash (3 crops). The last crop of tomatoes was in 1943.
The soil is a Sunniland fine sand with a pH of about 6.00, calcium and mag-
nesium levels of about 350 and 25 pounds per acre respectively and an organic matter
content of approximately 0.65 percent. There are several small spots within the area
where there is a thin layer of marl at depths of 6 to 24 inches. At such localized
spots the pH is quite high and the calcium level is correspondingly higher than average
II Fertilizer Tests with Early Yellow Crookneck Squash
Two tests were made with squash, one fall planting and one spring planting.
Planting was made on beds eifht feet apart, two rows per bed. The plots ware laid out
in a combination Latin square split plot design. The five main treatments were as
follows:
A. Check
B. 2 percent soluble MgO in mixed fertilizer
C. Gypsum broadcast at 1000 pounds per acre
D. Dolomite "
E. Basic slag "
Each main treatment was superimposed with two sub-treatments, namely, (1) no
minor elements and (2) minor elements consisting of 0.3, 0.4, 0.2, 0,12 and 0.3 percent
CuO, MnO, ZnO, B203 and Fe203 respectively, in the mixed fertilizer. All plots re-
ceived a 4-8^$ fertilizer, 750 pounds per acre in the bed before planting and 750 as a
single side application about two weeks after planting.
The total yields in bushels per acre of eight pickings for the fall crop
were as follows:
Main Minor Element Sub-treatment
Treatment (1) Without (2) With Average
A Check 168 178 173
B Soluble MgO 136 152 144
C Gypsum 160 166 163
D Dolomite 127 151 138
E Basic Slag 140 151 145
Average* 146 159
* Difference required for significance = 10
Page 2.
The total yields in bushels per acre of nine pickings for the spring crop
were as follows:
Main Minor Element Sub-treatment
Treatment (1) Without (2) With Average
A Check 301 278 289
B Soluble MgO 268 297 282
C Gypsum 277 248 262
D Dolomite 260 264 262
E Basic Slag 270 269 269
Average 275 271
Although not statistically significant, the highest yielding treatment for
both trials was the Check. Minor elements increased the yield for the fall crop but
not the spring crop. Analysis of data from individual plot yields indicated a ten-
dency for squash yields to decrease as the pH increased above 5.75. On the basis of
these tests it would seem best not to use any liming material, gypsum or soluble mag-
-'esia for squash if the soil pH is 5.75 or above. The use of minor elements in the
.'*bilizer is recommended.
III Fertilizer Tests with Tomatoes
The soil treatments for the tomato experiments were the same as those for
squash. The variety used was T1724-1-2, a wilt resistant variety from the U.S.D.A.
Vegetable Breeding Laboratory, Charleston, South Carolina. Plants were transplanted
to the field spaced 36 inches apart on beds eight feet apart. Fertilizer was applied
at the rate of 750 pounds per acre in the bed before transplanting and 1,500 pounds
side dressed on either side in two equal applications.
The fall planting was severely damaged by the January 15 freeze. The total
yields in field crates per acre of four pickings for the spring crop were as follows:
Main
Treatment
A Check
B Soluble MgO
C Gypsumn
D Dolomi te
E Basic Slag
Averagei~-
Minor Element Treatment
(1) Without (2) With
542 570
511 563
528 54h
574 603
62h 631
556 582
Difference required for significance = 45
**I = 25
The variations of tomato yields with treatment are highly significant. Basic
S ave the highest yield both with and without minor elements. Dolomite produced
Second highest yield. Treatments including minor elements in all cases yielded
better than those without minor elements. A careful study of the yield data from all
the plots indicated a tendency for tomato yields to increase as the pH increased from
5.h0 to 7.00.
Average *
556
537
536
588
627
I
Page 3.
Fruit from these plots had a tendency to become soft after picking and break
lown severely during shipment. In order to determine the relationship of this quality
,to treatment, one box of fruit was saved from each of the fifty plots during the fourth
picking. The fruit was picked, washed, and sorted one day. The next day it was run
over the belt at the packing house and waxed and immediately placed in a refrigerated
car. The tomatoes were removed from the car after six days and allowed to stand at
.::ospheric temperature for three more days. Ten days after picking the tomatoes were
examined for spoilage and internal quality. A four inch rain had occurred four days
prior to picking and all the fruit had become very badly water soaked. This condition
tended to mask out treatment differences. However, in spite of this, some highly sig-
nificant and valuable data were obtained.
The fruit was first examined for any type of spoilage visible from its ex-
terior. The spoilage showed no significant variations with treatment. Twenty-five
fruit from each lot were cut in half and examined first for puffiness. This examina-
tion showed no significant differences with treatment. The cut fruit was next examined
for internal break down. Such deterioration consisted of soft light colored, yellow or
sometimes brown necrotic spots on the linings of the walls between or around the out-
sides of the seed sections. Many of the fruit showing these symptoms had a strong
odor and taste of over-ripe tomatoes.
The percent of fruit from each treatment showing such deterioration were as
follows:
Main Minor Element Treatment
Treatment (1) Without (2) With Average*
A Check 50 42 46
B Soluble MgO 38 44 41
C Gypsum 46 38 42
D Dolomite 36 32 34
E Basic Slag 30 16 23
Average 40 34
Difference required for significance = 11
The variations of percentage deterioration with treatment were highly signi-
ficant. Fruit from the basic slag plots was statistically more sound than that from
any other treatment. Dolomite ranked second with a grade significantly better than the
check and somewhat superior to the soluble magnesia and gypsum treatments. The minor
element treatments as a whole were better than those that did not include minor ele-
ments but the differences between averages were not quite enough for significance.
The differences in fruit deterioration with treatment seem quite remarkable when the
best treatments.are compared to the check. For example, the basic slag treatment with
minor elements, Treatment E(2), showed only 16 percent breakdown as against 50 percent
for the check without minor elements, Treatment A(1).
Page h,
The results of this experiment with tomatoes substantiate those obtained
last year in the experiments conducted in St. Lucie County. In both experiments the
application of liming materials as soil amendments increased the yields and quality
with basic slag leading. Basic slag with minor elements gave the greatest yield of
the highest quality fruit. On the basis of results of these two experiments it is
recommended that tomatoes grown on the sandy soils of the lower East Coast of Florida
be fertilized as follows:
For pH below 5.10, use 2,000 pounds per acre of basic slag or dolomite.
For pH 5.10 to 6.10, use 1,000 pounds per acre of basic slag or dolomite.
For pH 6.20 and above, use no liming materials. When no dolomite or basic
slag is applied, use 2 percent soluble MgO in the mixed fertilizer.
The following fertilizer formula is recommended for tomatoes:
4-8-8/0.3/O.4/0.2/0.12/0.3, the last five figures refer to CuO, MnO,
ZnO, B203 and Fe203 respectively.
IV Miscellaneous Tests and Observations
Observation trials were made with several vegetable crops planted on a plot
half of which had been treated with dolomite and gypsum at the rate of 1000 pounds of
each per acre. A 4-8-8 fertilizer containing minor elements and soluble magnesia was
used to fertilize all the plantings. The soil characteristics were similar to those
described for the tomato and squash fertilizer experiments. Peppers, eggplant,
tomatoes, and watermelons showed a marked response to the soil amendments. Sweet
corn showed no response. Green beans showed a slight negative response. Lima beans
and cucumbers showed a marked decrease in yield with the dolomite, gypsum treatment.
Tomato seedlings for transplanting were successfully grown on old land by
the following recommended procedure: Apply liming materials as needed, turn up beds
and fertilize with a complete fertilizer well ahead of sawing. Raise the water table
so as to thoroughly moisten the soil and reestablish capillarity before seeding.
After seeding, cover the beds with a thin layer of coarse sawdust and maintain at
optimum moisture until seedlings appear. The sawdust mulch was shown by experiment
to be very beneficial in obtaining rapid, uniform and a high percentage germination
of seed. Recommended methods for the control of diseases and insects must be main-
tained until the seedlings are transplanted.
A preliminary study of transplanting methods indicated that the application
around the roots of the plant of moist soil from the furrow adjacent to the bed or
watering with starter solution was much superior to watering with plain water. Regard-
less of the method of transplanting the seedlings started much more rapidly and matured
about one week earlier when the beds had been fertilized prior to transplanting.
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