Everglades Station Mimeo EES65-29 1nTUR &
RESPONSE OF ESCAROLE TO pH ADJUSTMENT AND SOME T ER .
:NUTRITIONAL FACTORS ON NEW SAWGRASS PEAT IaQ
.H.. W. Burdine and V. L. -Guzman 2/ /
Work at the Everglades .Experiment Station by -Forsee and..Wolf esta shed the
response of leafy crops to pH and levels of P and K and correlated these with soil
tests. From this work, recommendations'for soil treatment and fertilization can be
made for these crops, with a high degree of success.
The recent expansion, of sugarcane acreage qn the older and warmer soil near
the Lake has pushed much of the vegetable industry out on new sawgrass land. In
many cases the pH on this new land ranges from 6.50 to 7.50. Leafy.crops such as,
escarole carry a smaller profit margin and some growers have felt that the expense
of lowering the pH with applications of agricultural sulfur was prohibitive. In
many cases poor growth, poor color, yellowing of lower leaves have occurred:on these
areas. It was felt that some work should be done to determine the elements most
likely to be limiting at these pH levels.
It is generally known that for some crops, one of the elements most likely to
be limiting on land where the pH is above 5.85-6.00 is manganese. Many growers
apply nutritional manganese sprays or dusts, but it is not known whether or-not -
other factors also limited by pH also affect yield and quality. Phosphorus avail-
ability is known to be affected by pH levels within the above pH ranges, but phos-
phorus seems to be readily available on.new soil, and somewhat larger amounts -are
not excessively expensive. It has long been known that copper, zinc and boron must
be added to soils in the area. Following initial adequate applications of zinc and
copper no known deficiencies of these elements have occurred. Zinc and 'copper is
also routinely applied in pest control programs for most of these crops. Boron is
routinely applied in annual fertilizer applications, as has been the case with
A winter and spring grown experiment was established on new land, slightly over
1 mile south of the Bolles Canal. The land had had recommended rates of copper and
zinc applied the previous season. It was covercropped to Sesbania and flooded for
the previous summer and early fall. A factorial experiment with 3 sulfur, 3 potassi-
um, 3 phosphorus treatments, with 3 replications was established and the fertilizer
treatments broadcast applied and disked in'eatly January 1964. The field was planted
to escarole January 7, and harvested on April 1 and 2, 1964. The plots were split
-and one-half of each plot received five applications of foliar manganese as 1 lb.
Manganese sulfate (32.5% Mn) in 100 gallons of water each week beginning February
I/ The writers acknowledge and appreciate the assistance given in this study by
grower-cooperators, A. Duda-and Sons, particularly to Mr. Warren Battle:and -
A. B. Collins, who furnished the experimental site,.sulfur used, and labor
used in the conduct of this experiment.
2/ Associate Soils Chemist and Associate Horticulturist, Everglades Experiment
Station, Belle Glade, Florida.
An accidental side dress application of 500 lbs. 5-14-20 with micro-nutrients
was made by the grower, and tillivated in on February 18 bringing treatment levels
up to the following amounts of materials applied in all combinations.
Sulfur Phosphorus Potassium
1. None 1. 70 lbs. P205/A. 1. 200 lbs. K20/A.
2. 2000 lbs./A. 2. 170 Ibs. P205 /A. 2. 300 lbs. K20/A.
3. 4000 lbs./A. 3. 270 lbs. P205 /A. 3. 400 Ibs. K20/A.
The following micro-nutrients were included uniformly in the fertilizer mix-
tures, in the broadcast treatments + the accidental side dress.
MnO 13.0 Ibs./A.
B203 9.1 lbs./A.
Disease control was done by the grower with routine Nabam + ZnS04 sprays.
Disease control was very good. The plot was harvested April 1 and 2, 1964.
Table 1. Soil Test Data.
SO No Sulfur Before treatment
No Sulfur At end of Experiment
S 2000 lb. Sulfur Before treatment
2000 lb. Sulfur At end of Experiment
S 4000 lb. Sulfur/Acre-Before
S 4000 lb. Sulfur/Acre-End
Yields were not significantly effected by phosphorus and potassium levels alone,
although there were potassium x pH interactions.
Table 2. Pounds per acre of trimmed marketable escarole as influenced by pH, potas-
sium and manganese applied to the foliage.
pH at .200 lbs. K20 300 lbs. K20 400 lbs. K20 pH and
Harvest per acre per acre per acre Mn ave.
6.63 No Mn 17,317 18,211 19,151 18,226
Mn 23,721 22,987 26,067 24,258
6.14 No Mn 21,413 20,381 21,802 21,199
Mn 24,576 24,202 25,295 24,691
5.64 No Mn 22,903 24,600 20,106 22,536
Mn 24,317 26,143 23,041 24,500
There was a significant potassium x pH interaction, in which the response was
linear at the pH levels of 6.63, but quadratic at pH.of,5.64,(Table 2).
Color Rating: Ratings were made for depth of green color. These ratings were
separated from lower leaf chlorosis. Each plot was rated as follows:
1. poor color
2. fair color
3. good color
4. excellent color
Phosphorus level effects were not significant, Potassium levels, pH and manganese
effects were significant (Table 3).
Table 3. Average color ratings of escarole at different pH and potassium levels
with and without manganese applied to the foliage.
Ave. pH at spray 200 Ibs. 300 lbs. .40.l.Ibs.. ..... pH..and
Harvest Mn K20/A. K20/A. K20/A. Mn/acre
6.63 No Mn 1.7 2.0 21' .. 1.9
n" 2.8: 3.3 33 .6 3.2
6.14 No Mn 2.3 2.6 2.8 2.6
M.n ':*.3.2 3.1. 3.7 3.3
5.64 No Mn 2.7 3.2 3.1 3.0
Mn 3.2 3.3 3.5 3.4
Manganese, pH, and potassium affected significantly the intensity of dark
.green color at harvest. Manganese foliar sprays on this new soil improved color
even at the lowest pH level. ...... .......
Lower leaf chlorosis: This condition is frequently seen on new land, especially
in the latter part of'the growing season. Plots were rated for the severity of this
malady from 1 = None ,---- to8 = very severe. ..
Average ratings are given in Table 4. Again phosphorus effects were not signi-
Table 4. Average ratings of chlorosis appearing on bottom leaves
pH and potassium levels, and manganese foliar sprays.
as affected by
p.H at Mn Foliar 200 lbs. 300 lbs. 400 lbs. Ave. for pH
Harvest Treatment K20/A, K20/A. K20/A. & Mn treatment
6.63 No Mn 4.7 2.8. 2.7 3.4
Mn 5.1 3.0 3.4 3.9
6.14 No Mn 3.8 3.4 1.6 2.9
Mn 3.9 3.4 2.0 3.1
5.64 No Mn 3.6 3.3 3.7 3.5
Mn 3.7 3.7 4.3 3.9
K Ave. 4.1 3.3 2.9
Increasing potassium levels significantly reduced lower leaf chlorosis, whereas
manganese levels significantly increased it. This may have been due to the large
growth response to manganese applied to the foliage, indicated in Table 1.
Hollowstem incidence: All plots showed some tendency to hollowstems. Some
individual plants showed severe hollowstem, but the average intensity of plants
exhibiting the disorder was not severe.
Data is presented showing percentage of plants exhibiting the disorder in
Table 5. Percentage of plants exhibiting very slight to very severe hcilowstem
symptoms as influenced by pH, potassium level and manganese foliar sprays.
Table 5. Percentage of plants showing hollowstem (or a tendency toward hollowstem).
pH at Mn foliar 200 lbs. 300 lbs. 400 Ibs. Ave.for pH
Harvest Treatment K20/A. K20/A. : K20/A. & Mn treatment
6.63 No Mn 55.0 49.9 53.7 52.8
Mn 73.7 72.1 82.0 75.9 64.5
6.14 No Mn 54.4 57.0 56.8 56.0
Mn 72.0 65.6 66.8 68.1 62.1
5.64 No Mn 47.9 54.5 54.7 52.4
Mn 55.5 57.5 47.8 53.6 53.0
Ratings for hollowstem. severity were:
to 8, very severe hollowness resulting
1 = dark ring only, 2 slight depression ----
in a cull plant.
Table 6. Average severity per plant of plants' showing hollowstem or a tendency to
pH at Mn foliar 200 lbs. 300 lbs. 400 lbs. Ave. for
Harvest Treatment K20/A. K20/A. K20/A. pH and Mn
6.63 None 1.9 1.6 1.7 1.7
Mn 2.6 2.3 2.5 2.5 2.1
6.14 None 1.7 1.6 1.7 1.7
Mn 2.4 2.1 2.0 2.2 1.9
5.64 None 1.5 1 1. 1.8 1.7
Mn 1.9 1.7 1.7 1.8 1.7
Only the effects of manganese and pH are significant.. The effects of manganese in
increasing both the percentage and severity of the disorder is probably due to the
growth response indicated in Table 5 and 6.
Effects of Treatment on Maturity: Very obvious differences were observed on
heart development between treatments. Differences were,observed from practically
no heart curling on the high.pH plots receiving 70 Ibs. P205/Acre and no supple-
mentary manganese, to a type of heart development rated as overmature on plots
where the pH was low and supplementary manganese was applied. Each plot was rated
for relative maturity by Mr. A. B. Collins, grower of the escarole according to the
following guide: : .
Slightly over mature*
.Over mature :
Very over mature
4* The Key Number
For this data, potassium effects were slight, overall phosphorus;effects small,
however along with pH and manganese phosphorus levels significantly affected ma-
turity. The large effects were due to pH and manganese treatments. Average relative
maturity ratings as indicated by heart development due to phosphorus pH and manganese
treatments are given in Table 7.
Table 7. Average maturity ratings based on heart development as
phorus rates, pH and manganese treatment.
affected by phos-
pH at Mn Foliar Lbs. P205 used per acre Ave. for
Harvest Treatment 70 170 270 pH & Mn
6.63 None 2.6 3.4 3.2 3.1
Mn 3.5 4.9 4.6 4.3
P Ave. 3.1 4.1 3.9 3.7
6.14 None 3.2 4.4 4.1 3.9
Mn 4.5 4.6 6.0 5.0
P Ave. 3.8 4.5 5.0 4.4
5,64 None 4.5 4.7 4.8 4.7
Mn 5.3 5.1 5.4 5.3
P Ave. 4.9 4.9 5.1 5.0
1. Manganese, outside regular P and K fertilization seems to be the element
most likely to be limiting growth of escarole on high pH soil provided adequate
zinc, copper and boron are used in fertilizer mix. Data here indicate that yield
and color intensity is improved on new land by manganese sprays even where pH is
lowered with a sulfur. Yields with adequate P and K fertilization were as high
at pH of 6.63 as at 5.64 with foliar manganese, applied weekly, the last 6 weeks of
the growing period. Hollowstem data indicated that under some conditions some
other factor may be important, and is also affected by pH.
2. Potassium levels significantly increased the intensity of the green color
along with foliar applied manganese and pH.
3. Lower leaf chlorosis was decreased with increasing potassium levels, but
increased by foliar manganese, possibly due to the increased growth obtained by
applications of foliar manganese.
4. Hollowstem percentage and intensity were increased by foliar manganese,
and decreased as the pH was lowered.
5. pH, phosphorus and manganese foliar sprays greatly affected relative heart
6. The best guide to fertility practices is obtained from a soil test.