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 Title Page
 Credits
 Table of Contents
 Description of white bud of...
 Distribution of white bud...
 Experiments on methods of correcting...
 Field experiments on the use of...
 Experiments on the use of zinc...
 Summary
 Literature cited














Group Title: Bulletin - University of Florida Agricultural Experiment Station ; 292
Title: use of zinc sulphate under corn and other field crops
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Permanent Link: http://ufdc.ufl.edu/UF00027676/00001
 Material Information
Title: use of zinc sulphate under corn and other field crops
Series Title: Bulletin - University of Florida Agricultural Experiment Station ; 292
Physical Description: Book
Language: English
Creator: Barnette, R. M.
Camp, J. P.
Warner, J. D.
Gall, O. E.
Publisher: University of Florida Agricultural Experiment Station
Publication Date: 1936
 Record Information
Bibliographic ID: UF00027676
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.

Table of Contents
    Title Page
        Page 1
    Credits
        Page 2
    Table of Contents
        Page 3
        Page 4
    Description of white bud of corn
        Page 5
        Page 6
        Page 7
    Distribution of white bud of corn
        Page 8
    Experiments on methods of correcting white bud of corn
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
    Field experiments on the use of zinc sulphate under corn
        Page 20
        Page 21
        Page 22
        Page 23
        Page 24
        Page 25
        Page 26
        Page 27
        Page 28
        Page 29
        Page 30
        Page 31
        Page 32
        Page 33
        Page 34
    Experiments on the use of zinc sulphate under other field crops
        Page 35
        Page 36
        Page 37
        Page 38
        Page 39
        Page 40
        Page 41
        Page 42
        Page 43
        Page 44
        Page 45
        Page 46
        Page 47
        Page 48
    Summary
        Page 49
        Page 50
    Literature cited
        Page 51
        Page 52
Full Text


Bulletin 292


UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATION
GAINESVILLE, FLORIDA
WILMON NEWELL, Director





THE USE OF ZINC SULPHATE UNDER

CORN AND OTHER FIELD CROPS


R. M. BARNETTE, J. P. CAMP, J. D. WARNER and 0. E. GALL


Fig. 1.-Typical field response to the application of zinc sulphate by corn
grown on soil producing white bud. All three rows were fertilized with
a 5-5-5 fertilizer at the rate of 445 pounds per acre. The rows on left and
right received in addition 12 pounds per acre of zinc sulphate.


Bulletins will be sent free to Florida residents upon application to
AGRICULTURAL EXPERIMENT STATION
GAINESVILLE. FLORIDA


March. 1936







EXECUTIVE STAFF

John J. Tigert, M.A., LL.D., President of the
University
Wilmon Newell, D.Sc., Director
H. Harold Hume, M.S., Asst. Dir., Research
Harold Mowry, M.S.A., Asst. Dir., Adm.
J. Francis Cooper, M.S.A., Editor
Jefferson Thomas, Assistant Editor
Clyde Beale, A.B.J., Assistant Editor
Ida Keeling Cresap, Librarian
Ruby Newhall, Administrative Manager
K. H. Graham, Business Manager
Rachel McQuarrie, Accountant

MAIN STATION, GAINESVILLE

AGRONOMY
W. E. Stokes, M.S., Agronomist"
W. A. Leukel, Ph.D., Agronomist
G. E. Ritchey, M.S.A., Associate*
Fred H. Hull, Ph.D., Associate
W. A. Carver, Ph.D., Associate
John P. Camp. M.S.. Assistant
ANIMAL HUSBANDRY
A. L. Shealy, D.V.M., Animal Husbandman**
R. B. Becker, Ph.D., Dairy Husbandman
W. M. Neal, Ph.D., Asso. in An. Nutrition
D. A. Sanders, D.V.M., Veterinarian
M. W. Emmel, D.V.M., Asst. Veterinarian
N. R. Mehrhof, M.Agr., Poultry Husbandman
W. W. Henley, B.S.A., Asst. An. Husbandman
Bradford Knapp, Jr., M.S., Asst. An. Husb.
P. T. Dix Arnold, B.S.A.. Assistant Dairy
Husbandman
L. L. Rusoff, M.S, Laboratory Assistant
Jeanette Shaw, M.S., Laboratory Technician
CHEMISTRY AND SOILS
R. W. Ruprecht, Ph.D., Chemist**
R. M. Barnette, Ph.D., Chemist
C. E. Bell, Ph.D., Associate
R. B. French, Ph.D., Associate
H. W. Winsor, B.S.A., Assistant
ECONOMICS, AGRICULTURAL
C. V. Noble, Ph.D., Agricultural Economist*
Bruce McKinley, A.B., B.S.A., Associate
Zach Savage, M.S.A., Associate
A. H. Spurlock. M.S.A.. Assistant
ECONOMICS, HOME
Ouida Davis Abbott, Ph.D., Specialist"*
C. F. Ahmann, Ph.D., Physiologist
ENTOMOLOGY
J. R. Watson, A.M., Entomologist**
A. N. Tissot, Ph.D., Associate
H. E. Bratley, M.S.A., Assistant
HORTICULTURE
A. F. Camp, Ph.D.. Horticulturist**
G. H. Blackmon, M.S.A., Horticulturist and
Associate Head of Department
A. L. Stahl, Ph.D., Associate
F. S. Jamison, Ph.D., Truck Horticulturist
R. J. Wilmot, M.S.A., Specialist, Fumigation
Research
R. D. Dickey, B.S.A.. Assistant Horticulturist
PLANT PATHOLOGY
W. B. Tisdale, Ph D., Plant Pathologist*
George F. Weber, Ph.D., Plant Pathologist
R. K. Voorhees, M.S., Assistant***
Erdman West, M.S., Mycologist
Lillian E. Arnold, M.S., Assistant Botanist
Stacy O. Hawkins, M.A., Assistant Plant
Pathologist
SPECTROGRAPHIC LABORATORY
L. W. Gaddum, Ph.D.. Biochemist
L. H. Rogers, M.A., Spectroscopic Analyst


BOARD OF CONTROL
Geo. H. Baldwin, Chairman, Jacksonville
A. H. Wagg, West Palm Beach
Oliver J. Semmes, Pensacola
Harry C. Duncan, Tavares
Thomas W. Bryant, Lakeland
J. T. Diamond. Secretary, Tallahassee

BRANCH STATIONS
NORTH FLORIDA STATION, QUINCY
L. 0. Gratz, Ph.D., Plant Pathologist in
Charge
R. R. Kincaid, Ph.D., Asso. Plant Pathologist
J. D. Warner, M.S., Agronomist
Jesse Reeves, Farm Superintendent
CITRUS STATION, LAKE ALFRED
A. F. Camp, Ph.D., Horticulturist in Charge
John H. Jefferies, Superintendent
W. A. Kuntz, A.M., Assoc. Plant Pathologist
B. R. Fudge, Ph.D., Associate Chemist
W. L. Thompson, B.S., Asst. Entomologist
EVERGLADES STATION, BELLE GLADE
A. Daane, Ph.D., Agronomist in Charge
R. N. Lobdell, M.S., Entomologist
F. D. Stevens, B.S., Sugarcane Agronomist
Thomas Bregger, Ph.D., SugarcanePhysiologist
G. R. Townsend. Ph.D., Assistant Plant
Pathologist
J. R. Neller, Ph.D., Biochemist
R. W. Kidder, B.S., Assistant Animal
Husbandman
Ross E. Robertson, B.S., Assistant Chemist
B. S. Clayton, B.S.C.E., Drainage Engineer
SUB-TROPICAL STATION, HOMESTEAD
H. S. Wolfe, Ph.D., Horticulturist in Charge
W. M. Fifield, M.S., Asst. Horticulturist
Geo. D. Ruehle. Ph.D., Associate Plant
Pathologist
W. CENTRAL FLA. STA., BROOKSVILLE
W. F. Ward, M.S.A., Asst. An. Husbandman
in Charge*

FIELD STATIONS
Leesburg
M. N. Walker, Ph.D., Plant Pathologist in
Charge
W. B. Shippy, Ph.D,. Asso. Plant Pathologist
K. W. Loucks, M.S.. Asst. Plant Pathologist
J. W. Wilson, Ph.D., Associate Entomologist
Plant City
A. N. Brooks, Ph.D., Plant Pathologist
Cocoa
A. S. Rhoads, Ph.D., Plant Pathologist
Hastings
A. H. Eddins, Ph.D., Plant Pathologist
Monticello
G. B. Fairchild, M.S., Asst. Entomologist***
Bradenton
David G. Kelbert, Asst. Plant Pathologist
C. C. Goff, M.S., Assistant Entomologist
Sanford
E. R. Purvis, Ph.D., Assistant Chemist,
Celery Investigations
Lakeland
E. S. Ellison, Ph.D., Meteorologist*
B. H. Moore, A.B., Asst. Meteorologist*
W. O. Johnson, B.A., Asst. Meteorologist*
R. T. Sherouse, Asst. Meteorologist*
M. L. Blanc, Asst. Meteorologist*

*In cooperation with U.S.D.A.
Head of Department.
** On leave.














TABLE OF CONTENTS
Page
Introduction ........ ........ 5
Description of White Bud of Corn 5
Distribution of White Bud of Corn ..... ..8
Some Other Types of Chlorosis of the Corn Plant.. ..........
Experiments on Methods (,f Correction of White Bud of Corn 9
(a) With Compounds of less common elements and a mixed inorganic
fertilizer ............ .. ...... .. ........ 12
(b) With animal manures..... ...... ... ..... 12
(c) W ith crude organic materials ..... ... ........ ...... 12
(d) By soil management......... ..... .... .. .. ..... 15
Field Experiments on the Use of Zinc Sulphate under Corn... 20
With fertilizer mixture containing organic ammonia source 20
W ith urea as a side-dressing ............................ .. 21
Rates of application.... ... ....... ..... ..... .. 23
W ith nitrate nf soda as a side-dressing .................. ........ 25
Effects of separate and combined applications with fertilizer mix-
tures containing superphosphate ... ........ ......... 27
R esidual effect ............ .................. .. .... .. ....... ......... .... 34
Experiments on the Use of Zinc Sulphate under Other Field Crops 35
Peanuts ............. ........ ................ .. 35
O ats ........... ... ..... .. 38
Velvet Beans .... .. ..... 39
Cowpeas .... .. .... ...... ... 41
Pearl Millet ......... ....... 45
Miscellaneous field crops .... ... 47
Summary..... ........ .. .. 49
Literature Cited 51









A


Fig. 2.-Seedling stage of white bud in the corn
plant. Corn planted April 7, photographed April
24, 1934. (After Soil Science.)


Fig. 3.-Advanced stage of white bud of the
corn plant. Long Island Beauty planted February
4 and photographed April 24, 1934. (After Soil
Science.)







THE USE OF ZINC SULPHATE UNDER CORN
AND OTHER FIELD CROPS

R. M. BARNETTE, J. P. CAMP, J. D. WARNER and 0. E. GALL

The past several years have marked the introduction of com-
pounds of some of the so-called secondary plant nutrients or
less abundant elements into the fertilizing programs of a number
of Florida crops. Among the most important of the recent
findings is the observation by Mowry (5)1 that zinc sulphate will
correct a malnutrition of the tung tree when applied to acid
mineral soils. The experiments of Mowry on the tung tree
have been enlarged upon and reported by Mowry and Camp (6).
In addition to these studies, systematic studies have been con-
ducted to determine the effect of compounds of less abundant
elements on the growth and for the correction of certain physio-
logical disturbances of a number of field crops. One of the most
important results of these experiments has been the observation
that zinc sulphate when applied to acid mineral soils will correct
a form of chlorosis of the corn plant called white bud and will
give increased yields of corn on lands on which the disease
occurs. It is the purpose of this bulletin to give an account
of experiments conducted on the use of zinc sulphate and other
methods for the correction of white bud of corn and for the
stimulation of growth of some other field crops.

DESCRIPTION OF WHITE BUD OF CORN
A chlorosis or yellowing of the corn plant, usually called white
bud, has been known to occur in the fields of central, north and
northwest Florida for a number of years. In affected soil areas
symptoms of white bud begin to appear within a week or two
after the emergence of the corn seedlings. The full develop-
ment of the chlorophyll in the older leaves of the seedlings
scarcely takes place before light yellow streaks appear between
the veins. Small white spots of inactive or dead tissue develop
rapidly in the leaves, while some small white areas that never
have chlorophyll often are present. The unfolding buds have

Acknowledgments: The authors wish to thank Dr. G. F. Weber and Mr.
D. G. A. Kelbert for taking the photographs used in this bulletin. Mr.
W. E. Stokes and Dr. R. W. Ruprecht assisted in planning the experiments
and preparing the manuscript.
1 Italic figures in parentheses refer to "Literature Cited" in the back
of this bulletin.





Florida Agricultural Experiment Station


leaves that are white to light yellow in color. This latter char-
acteristic has given rise to the use of the term white bud by
farmers. Some of these symptoms are shown in Figure 2.
An advanced stage of white bud is illustrated in Figure 3.
The plant had lower older leaves which were partially dead. In
many places the tissue had fallen away or contracted so as to
give the leaves a distorted appearance. The upper leaves had
yellow striping between the veins. The internodes of the plant
were definitely shortened and growth was stunted.


Fig. 4.-White bud (left) and healthy corn leaves of the same age.
Planted February 4 and photographed April 24, 1934.

Typical specimens of injury to the leaves of the affected corn
plants are compared with a healthy leaf in Figures 4 and 5.
The blades photographed for Figure 4 are the same age. The
blade on the left is a close-up view of the striping shown in the
plant photographed for Figure 3. The contrast between the
chlorotic and healthy leaves is evident. Figure 5 illustrates the
more advanced stages of leaf injury. These affected leaves
usually are the lower leaves of the chlorotic plant. They vary
in color from bronze to gray and, as stated above, often are
distorted with areas of dead tissue. These leaves usually are
dead before the maturity of the plant.





The Use of Zinc Sulphate Under Field Crops


Fig. 5.-Advanced stages of injury to leaves of chlorotic corn plants
compared with a healthy leaf. Corn planted March 3 and photographed
April 24, 1933. From left to right: Reddish bronze color over the entire
leaf; light slate colored leaf which is practically dead; healthy leaf; leaf
is green about midrib with slate colored edges; and dead straw-colored leaf
which has been depleted of chlorophyll with the exception of green streaked
midrib. (After Soil Science.)

Examination of the root systems of white bud plants and
apparently healthy plants has shown that both develop healthy
root systems during the early stages of growth.
Tests of different varieties of corn on the Experiment Station
farm have shown that those yielding best on the poorer sandy
soils are more resistant to white bud than the high yielders
on more fertile soils.' However, even the more resistant varieties
show white bud symptoms on severely affected soil areas.
From observations on the Experiment Station farm, the date
of planting apparently has no definite effect on the ultimate
development of white bud in the corn plant. The earlier plant-
ings in February and March grow slower and the symptoms may
be observed more readily than in plantings made in April, May
and June.
There is a seasonal variation in the intensity of white bud
of corn in most fields, but this variation has not been correlated
with any weather or soil factor. In fields where white bud does
1 Observations by Dr. F. H. Hull, Associate Agronomist.





Florida Agricultural Experiment Station


not develop too severely, the corn plants may show the chlorotic
condition in the early stages of growth and later develop into
apparently healthy plants. It has been observed that even this
transitory seedling stage of chlorosis may stunt the growth and
decrease the yield of corn. In severely affected fields, the corn
plants never recover completely from physical symptoms of
malnutrition.
An entire field of corn may show symptoms of white bud in
varying degrees, but there are generally areas in which plants
are more severely affected than in others. Such areas usually
are not distributed uniformly over the field and are irregular
in shape. Up to the present no correlation has been detected
between the location and distribution of these severely affected
areas and any soil characteristic.

DISTRIBUTION OF WHITE BUD OF CORN
During the late spring of 1934, a general survey of the more
accessible corn fields of central, north and northwest Florida
was made to ascertain the severity of white bud. Observations
extended from the southeastern part of Marion County to the
northwestern part of Santa Rosa County. Very few sections
were found to be free from white bud of corn. The chlorosis
was most widely distributed in the fields which had been cropped
every year. These areas embrace some of the best general
farming land in the state. They include the loamy phases of
the Norfolk, Orangeburg, Greenville and Tifton soil series.
On the poorer sandy soils where "land resting" is practiced,
the occurrence of white bud is limited. "Land-resting" consists
of alternating fields between cultivated crops and a fallow of
volunteer weeds and grasses in a two or three year rotation. This
rotation is a long established practice in the general farming
areas located on the sandier soil types.
With the exception of observations made in areas practicing
"land resting", there appeared to be no general correlation be-
tween any cultivation, fertilization or cropping system and the
occurrence of white bud in the corn fields.
At Gainesville, on the Experiment Station farm, white bud
of corn has developed severely on continuously cropped lands
despite the liberal use of commercial fertilizers and the incor-
poration of heavy summer cover crops of crotalaria and beggar-
weed. The soil types are Norfolk medium fine sand and Hernando
medium fine sand. Some areas on the farm have been affected





The Use of Zilu Sulphate Under Field Crops


so severely that corn fails to grow. Pathologic and genetic
studies have failed to couple this disturbance of the healthy
growth of the corn plant with a disease organism or with a
genetic factor.

SOME OTHER TYPES OF CHLOROSIS OF THE CORN PLANT
Before considering the corrective measures to be used for
white bud of corn, attention is called to several other types of
chlorosis which may resemble white bud in some respects. Jones
(4) reports a type of chlorosis of corn which was found due
to a deficiency of magnesium. Cooper and Moore (2) likewise
describe a chlorosis of corn plants brought about by a deficiency
of magnesium in the Coastal Plains of South Carolina. Skinner
and Ruprecht (8) report a chlorotic condition of the corn plant
growing on marl soils. This chlorotic condition was corrected
through the use of manganous sulphate. Pettinger, Henderson
and Wingard (7) describe three types of chlorosis of corn plants
grown in sand cultures with nutrient solutions. One type was
attributed to a deficiency of magnesium, another to a deficiency
of manganese, and a third to an excess of sodium in the nutrient
medium. In central, north and northwest Florida on well drained
acid soils, the prevalent type of chlorosis is white bud., To date,
the type of chlorosis produced by a deficiency of magnesium
has not been observed in Florida, and -the chlorosis produced
by a manganese deficiency has been observed only on marl soils
and on organic soils deposited on marl and definitely alkaline in
reaction. These types of chlorosis, due to their more or less
specific occurrence, should not be confused with white bud of
corn.
EXPERIMENTS ON METHODS OF CORRECTING
WHITE BUD OF CORN
Because of the severity of white bud of corn in the fields of
the station farm at Gainesville, experiments were started in
1931 to find the cause and cure of this disease. Warner (9)
reports from those experiments that a crude manganous sul-
phate, which was later found to contain zinc, partially overcame
white bud and that stable manure completely overcame it.
A more intensively controlled experiment was initiated on
an area of Norfolk medium fine sand and Hernando fine sand
on the Experiment Station farm in 1933. The experimental area
had grown corn plants in 1932 which were affected severely





Florida Agricultural Experiment Station


with white bud. Barnette and Warner (1) have reported an
account of those experiments. As the details have been de-
scribed, their report is summarized here.
Two general sets of soil treatments were used in the experi-
ment. The first involved the use of a mixed inorganic fertilizer
made from nitrate of soda, superphosphate and muriate of pot-
ash, with and without the addition of inorganic compounds of
some of the less abundant elements. The second involved the
use of a variety of organic materials in some cases in combina-
tion with inorganic compounds of some of the less abundant
elements. The different treatments and their rates of application
per acre are given in Table 1.
TABLE 1.-TREATMENTS APPLIED IN STUDIES OF CHLOROSIS OR WHITE BUD
OF CORN.
MATERIALS APPLIED TO SOIL
Lbs. per acre
Nothing No special treatment

MIXED INORGANIC FERTILIZER AND SUPPLEMENTS
8-8-4, Nitrate of soda, superphosphate, muriate of potash
8-8-0 + 200 lbs. muriate of potash
8-8-0 + 375 lbs. sulphate of potash-magnesia
8-8-4 + 400 lbs. Epsom salts
8-8-4 + 50 lbs. manganous sulphate
8-8-4 + 200 lbs. manganous sulphate
8-8-4 + 1,000 lbs. dolomitic limestone
8-8-0 + 200 lbs. muriate of potash and 200 lbs. manganous sulphate
8-8-4 + 20 lbs. zinc sulphate (ZnSO4.7H20)
8-8-4 + 500 lbs. flowers of sulphur
8-8-4 + 500 lbs. flowers of sulphur and 50 lbs. manganous sulphate
8-8-4 + 1,000 lbs. basic slag
8-8-0 + 375 lbs. sulphate of potash-magnesia and 200 lbs. manganous
sulphate
0-8-4 + 50 lbs. manganous sulphate and 178 lbs. calcium nitrate

ORGANIC MATERIALS AND SUPPLEMENTS
21/2 tons air-dried chlorotic Crotalaria spectabilis (broadcast)
22 tons air-dried healthy Crotalaria spectabilis (broadcast)
2 V tons natural leaf mold from mixture of hardwoods and pine (broadcast)
2 tons natural leaf mold (broadcast) and 50 lbs. manganous sulphate
(in row)
4 tons stable manure (horse)
2 tons chicken manure (without litter)
400 lbs. Peruvian guano
5 tons acid peat from localized peat deposit near LaCrosse, Fla.
5 tons acid peat and 50 lbs. of manganous sulphate
5 tons alkaline peat from Everglades Station, Belle Glade, Fla.
5 tons alkaline peat and 50 lbs. manganous sulphate
5 tons alkaline peat and 20 lbs. zinc sulphate (ZnSO..7H0)
5 tons alkaline peat and 1,000 lbs. basic slag
Formulas stated in following order: NH--P20--KzO. All mixed fer-
tilizer applied at rate of 400 lbs. per A.










O

1 !
N








Fig. 6.-Effect of zinc sulphate in combination with an inorganic fertilizer on the development of the corn plant on soil
areas which produce chlorotic plants. Whatley's Prolific corn, planted April 7 and photographed June 22, 1933. Left, no
treatment; center, 400 pounds per acre of an 8-8-4 inorganic fertilizer made from nitrate of soda, superphosphate and mu-
riate of potash applied in the row; right, 400 pounds of the inorganic fertilizer and 20 pounds per acre of zinc sulphate
(ZnSO4.7H0O) applied in the row. (After Soil Science.)





Florida Agricdultral Experiment Station


The fertilizers, organic materials and supplements were ap-
plied in the row except where otherwise indicated. Whatley's
Prolific corn was used in the experiment. This study of the
corrective measures for white bud of corn and other observations
on white bud falls naturally under several heads which will be
discussed separately.
a. Use of Compounds of Some Less Common Elements with a
Mixed Inorganic Fertilizer
The only inorganic fertilizer combination which brought about
a healthy development of the corn plants was 400 pounds of the
8-8-4 mixture with 20 pounds of "chemically pure" zinc sulphate
(ZnSO4.7HO) per acre. As may be seen from Figure 6 the
plants receiving this treatment made a healthy growth as com-
pared with the stunted growth of the plants receiving no fer-
tilizer and those receiving 400 pounds of the mixture without
the zinc sulphate. The yields of corn on the zinc sulphate treated
plots were the highest of the plots receiving the inorganic com-
binations. The plants of the plots receiving an application of
400 pounds per acre of an 8-8-0 inorganic mixture with an ad-
dition of 375 pounds of commercial sulphate of potash-magnesia
and 200 pounds of commercial manganous sulphate were the
only other plants among the plots receiving inorganic combina-
tions showing substantial recovery from white bud and an in-
creased growth. The crude manganous sulphate when tested
was found to contain appreciable quantities of zinc.
b. Use of Animal Manures
Stable manure applied at the rate of 8,000 pounds per acre
in the row brought about a healthy development of the corn
plant, produced the most vigorous growth and the highest yield
of corn. Chicken manure applied at the rate of 4,000 pounds
per acre in the row stimulated growth and caused a very large
increase in yield. Both of these manures when tested spectro-
graphically1 showed relatively large quantities of zinc. Figure
7 shows plants grown with these manures in comparison with
those grown on an untreated plot.
c. Use of Crude Organic Materials
Natural leaf mold collected from a mixture of hardwoods and
pines when applied broadcast at the rate of 5,000 pounds per
acre, and when applied in combination with 50 pounds per acre

1 All spectrographic tests were made in the Spectrographic Laboratory
of the Florida Agricultural Experiment Station under the direction of Dr.
L. W. Gaddum.


























Fig. 7.-Effect of manures on the development of the corn plant on soil areas which produce chlorotic plants. Whatley's
Prolific corn planted April 7 and photographed June 22, 1933. Left, no treatment; center, 8,000 pounds of stable manure
per acre applied in the row; right, 4,000 pounds per acre of chicken manure without litter applied in the row.


a

~2ri





Florida Agricultural Experiment Station


of the commercial manganous sulphate in the row produced
healthy corn plants and increased the grain yield.
Figure 8 shows the growth of corn on the leafmold plots
compared with the growth on an untreated plot.



















Fig. 8.-Effect of leafmold from combined pine and hardwood hammock
on the development of the corn plant on soil areas which produce chlorotic
plants. Whatley's Prolific corn planted April 7 and photographed June 22,
1933. Left, no treatment; right, 5,000 pounds per acre of leafmold applied
broadcast and worked into the surface soil.

Alkaline peat at the rate of 10,000 pounds per acre in the
row and in combination with 50 pounds per acre of commercial
manganous sulphate caused some improvement in the chlorotic
condition of the corn and an increased yield. The alkaline peat
plots with the 20 pounds per acre of "chemically pure" zinc
sulphate (ZnSO4.7HsO) produced the most vigorous plants of
the peat series, increased plant growth, and gave the second
highest grain yields of the experiment.
Figure 9 shows the plants grown with alkaline peat alone
and those grown with alkaline peat and zinc sulphate. The
application of alkaline peat in combination with 1,000 pounds
per acre of basic slag in the row caused an accentuation of the
chlorotic condition and a greatly decreased yield.
Acid peat, chlorotic Crotalaria spectabilis, healthy Crotalaria
spectabilis, and Peruvian guano failed to prevent the chlorotic
condition of the corn or to increase plant growth and corn yields.






The Use of Zinc Sulphate Under Field Crops


Fig. 9.-Effect of alkaline peat in combination with zinc sulphate on
the development of the corn plant on soil areas which produce white bud.
Whatley's Prolific corn planted April 7 and photographed June 22, 1933.
Left, 10,000 pounds of alkaline peat from Belle Glade, Fla., applied in the
row; right, 10,000 pounds of alkaline peat and 20 pounds of zinc sulphate
(ZnSO..7H,O) applied in the row. (After Soil Science.)

Ashes of all the organic materials were tested spectrographic-
ally for the presence of zinc. All contained appreciable quantities
of zinc. The interesting and perhaps practical aspect of these
observations is that only certain of them were found to produce
healthy corn plants on areas affected with white bud.
d. Soil Management as a Corrective Measure for White Bud
of Corn
In addition to the experiment reported by Barnette and War-
ner (1), a rotation experiment of corn interplanted with peanuts
has been conducted on the Experiment Station farm for the
past few years. This experiment afforded an opportunity for
the study of the effect of several soil management and cropping
systems on the occurrence of white bud of corn. The experiment
is located on a field from which a crop has been removed annually
for a number of years. White bud of corn had been very severe
in the field for the past four or five years. The soil of this field
is classified as Norfolk medium fine sand and Hernando medium
fine sand.






Florida Agricultural Experiment Station


The rotations which are being compared in this field are:-
1. A two-year fallow of volunteer weeds and grasses followed
by corn interplanted with peanuts.
2. A one-year fallow of volunteer weeds and grasses followed
by corn interplanted with peanuts.
3. A planted summer cover crop of crotalaria (mixture of
C. spectabilis and C. striata) followed by corn interplanted
with peanuts.
4. Corn interplanted with peanuts and crotalaria grown an-
nually with a winter cover crop of rye or oats.
5. Corn interplanted with peanuts grown annually.
Each plot is 35 feet wide and 740 feet long. The plots are
laid out side by side in the order named. Each of the plots is
quadruplicated, making four tiers of the plots in the field. No
commercial fertilizers are used in the experiment. Corn and
peanuts are planted in 7 foot rows in each plot. In addition,
peanuts are planted in the middles. The middle three rows of
each plot are used for measurements.
In 1933, the plots were grown to volunteer and planted summer
cover crops or to corn and peanuts as indicated. In 1934, corn
and peanuts were planted on all plots except the two-year fallow
plots. Whatley's Prolific corn was planted in March. Counts
of the percentage of chlorotic plants and of the number of corn
plants were made on April 28 and June 20, 1934. The results
of these counts are given in Tables 2 and 3.
The results show that "resting the land" or permitting it to
lie fallow to volunteer weeds and grasses has reduced materially
the percentage of white bud corn plants in the plots. The in-
corporation of a relatively heavy planted cover crop of crotalaria
had not been as effective as the fallow in reducing the white
bud of corn. The corn on the plots planted to corn and peanuts
annually showed by far the largest percentage of white bud.
The count of the number of plants on April 28 (Table 3) shows
that in the early growth stages there was a uniform stand of
corn over all the plots. The count on June 20, after all replanting
had been done and the corn was approaching maturity, shows
that the stand of corn on the plots planted yearly to corn and
peanuts had been materially reduced in comparison with that
produced on plots which had remained fallow the previous year.
The plots on which the high yielding summer leguminous cover
of crotalaria had been grown and incorporated also showed a
decrease in number of plants.






'TABLE 2.-1 PERCENTAGE OF WHITE l3lrI CORN PLANTS IN PILOTS OF "LAND RESTING" EXPERIMENT.


Rotation



"Rested" to weeds and grass in 19313.
Corn and peanuts in 1934.

Cover crop of crotalaria in !:933.
Corn and peanuts in 1934.

('Corn, peanuts and cr(ttalaria iln 1933 and 1i931.

Corn and pealuts in 19;33 and 1934.


Tier
1E

49.4


7(6.2


83.5

88.0


April 28, 19i4

Tier Tier Tier
2 4

:1!.2 4.1.7 :17.2


Aver-
age

42.6


79.4 71.3


85.4 75.3

41.6; 78.14


June 20, 1934

Tier Tier Tier Tier Aver-
1E 2 3 41 age

21.6 11.6 9.4 I 5.2 1 1.9


50.5 14.; 2(;.0 9.5 25.2


(6 1.:; 37.6 36(;. 11.5 36.S

56<.3 52.5 38.4 18.4 41.4


TABLE 3.--IREATIVE STAND OF CORN PLANTS ON BASIS OFi "RESTED" PLOTS IN "LAND RESTING" EXPERIMENT.


Rotation



"Rested" to weeds and grass in 193:3.
Corn and peanuts in 1934.

Cover crop of crotalaria in 1933.
Corn and peanuts in 1934.

Corn, panluts and crotalaria in 19;33 and 19-l4.

Corn and peanuts in 1933 and 193,1.


Tier
1 E

11)1)


April 28, 1934

Tier Tier Tier
2 3 4

100 100 1(00


95.2 9!8.6;


101.4

103.9!


o 91.8

00.4


Aver-
age

100


102.0 96.9 98.2


99.2 100.4 100.2
1.4 98.8 101.1
102.4 98.8 1 101.1


June 20, 1934

Tier Tier Tier Tier Aver-
SE 2 3 4 age

100 100 100 100 100


88.5 94.1; 94.8 92.7 92.7


81.3 75.8 83.8 89.5 82.6

77.5 77.8 8.1.2 82.4 80.5






Florida Agricultural Experiment Station


In 1935, the plots "rested" two years to weeds and grasses
and the annually planted plots of this rotation experiment were
grown to corn and peanuts. Counts of the number of corn plants
on the plots were made on April 14 and June 12. The relative
stand of corn on the basis of the number of plants on the "rested"
plots is given for these two dates in Table 4. The stand of corn
on all the plots was fairly uniform on April 14. The count made
on June 12 shows that the relative stand of corn had been
materially reduced on the annually planted plots. White bud
was very severe on these annually planted plots while it was
not severe enough to reduce the stand on the "rested" plots.
Some white bud occurred in the "rested" plots but the plants
grew out of the early symptoms of malnutrition. The plots
"rested" two years to weeds and grasses appeared much healthier
than the annually planted plots during the entire growing season.
Additional information on the reduction of the stand of corn
in fields where white bud occurs was obtained from a field which
had been planted to corn and peanuts annually for a number
of years. The occurrence of white bud in the field was very
irregular. The south portion of the field was not nearly so
severely affected as the north portion. The south portion had
received an application of stable manure in 1931. The field had
been cropped annually to corn or corn and peanuts since that
date. In 1935, the corn was planted in five foot rows, three feet
in the drill. The number of corn plants was counted in 10 row
plots on April 13 and again on June 11. The total number of
plants on these plots for the two dates and the percent reduction
of the stand between April 13 and June 11 are given in Table 5.
These data show very little reduction of the stand in the south
portion of the field but a very severe reduction in the plots to
the north. The reduction of the stand was as much as 64.0
percent in one of the plots. The average percentage reduction
of the corn stand for the field was 23.3 percent.
From these data it is evident that corn plants may die from
white bud in severely affected areas and thus grain yields may
be very materially reduced.
"Resting the land" and the use of animal manures and certain
types of rough organic materials appear useful in controlling
the white bud condition of corn. However, the use of zinc sul-
phate appears to offer some economical advantages. For this
reason, a number of field experiments were conducted during













"Re
Cor

Cor
Oat

Cor


TABLE 4.-RELATIVE STAND OF CORN PLANTS ON BASIS OF "RESTED" PLOTS IN "LAND RESTING" EXPERIMENT. 1935.

April 14 June 12
Rotation
Tier Tier Tier Aver- Tier Tier Tier Ave
1E 2 3 age I E 2 3 ag

sted" to weeds and grass in 1933 and 1934. 100.0 100.0 100.0 100.0 100.0 100.0 100.0 10
n and peanuts in 1935. I

n, peanuts and crotalaria in 1933, 1934 and 1935. 92.6 102.3 92.2 95.7 79.6 82.3 74.4 7:
s in winter of 1934.

n and peanuts in 1933, 1934 and 1935. 100.2 103.5 94.5 99.4 81.1 78.9 77.1 7


r-
e

0.0


8.8


9.0


TABLE 5.--VARIABLE REDUCTION OF CORN STAND IN A FIELD AFFECTED WITH WHITE BUD.

Plot Numbers South to North
Plants per Plot I I I I I I
1 2 :1 1 5 6 7 8 9 10 11 12 13 14 15 16


April 13, 1935 1075 1077 1085 080 1077 1074 1072 1073 1063 1064 1070 1063 1048 1059 1058


June 11, 1935 1053 1060 1045 1030 1044 1009 997 919 849 858 773 498 383 507 527 605


Percent reduction of stand 2.1 1.6 3.7 4.6 3.3 6.3 7.2 14.3 20.9 19.3 27.4 53.5 64.0 51.6 50.2 42.8

Average-23.3('; reduction of stand.






Florida Agricultural Experiment Station


1934 and 1935 to test the value of zinc sulphate for correcting
the white bud condition of corn and stimulating the growth of
other field crops on land producing white bud of corn.

FIELD EXPERIMENTS ON THE USE OF ZINC SULPHATE
UNDER CORN

With Fertilizer Mixture Containing Organic Ammonia Source.
Experiments have been conducted on the Experiment Station
Farm at Gainesville where white bud of corn has developed
irregularly over all the corn fields. The soils of the fields are
Norfolk medium fine sand and Hernando medium fine sand. One
field had been cropped continuously for a number of years. On
the west half of the field the corn was a complete failure in 1933,
due to the severe development of white bud. On the east half
of the field the corn grew very irregularly in 1933. Some areas
showed severe white bud symptoms while other areas produced
apparently healthy corn.
In the spring of 1934 the field was laid out so that the rows
ran east and west. Twelve four-row plots were given row ap-
plications of 445 pounds per acre of a 5-5-5 fertilizer mixture
made from nitrate of soda, cottonseed meal, superphosphate and
muriate of potash mixed with 12 pounds per acre of zinc sulphate
(89C ZnS04)1. Sixty percent of the ammonia of the mixture
was derived from nitrate of soda and 40 percent from cottonseed
meal. Single rows between the plots receiving the application
of zinc sulphate were fertilized with the mixture without zinc
sulphate. These plots were replicated 11 times in the field. The
fertilizer was applied in the row a few days before the corn
was planted.
Whatley's Prolific corn was planted in March, 1934, and har-
vested in September. The field was divided into east and west
halves for harvesting, and the weights of the slip-shucked corn
of the individual rows were taken. The average yields of corn
calculated in bushels per acre are given in Table 6, while Figure
1 shows the typical response of the corn plant to the application
of zinc sulphate to the severely affected soils of the west half.
The application of 12 pounds of zinc sulphate (89% ZnSO4)
increased the yield of corn 31.59 percent on the better half of
the field and 74.47 percent on the more severely affected half.

1 A very pure grade of zinc sulphate (89% ZnSO) was used in all field
experiments.






Thc(' of Zia-c S>ulphatc Utider Field Crops


TABLE 6.-AVERA(;E YIELDS OF CORN GROWN ON EXPERIMENT STATION
FARM WITH AND WITHOUT ZINC SULPHATE.

East side of field West side of field
showing spotted showing severe
white bud condition white bud condition


Without zinc sulphate 12.85 bu. A 9.01 bu.'A

With zinc sulphate
(12 pounds per acre in the row) 16..1 bu. A 15.72 bu.'A

Increase in yield due to zinc
sulphate :1.5 ', 74.47'

NOTE: A general application of 445 lbs. per acre of a 5-5-5 fertilizer
was made.

With Urea as a Side-Dressing.-In another experiment in 1934
zinc sulphate was used where urea was tested as a side-dressing
material for corn. The field in which this test was conducted
had been cultivated annually for a number of years. Corn grown
on the land in 1933 had shown very severe injury from white
bud and the urea side-dressings gave no measurable increase in
yield. The soil for the most part is Norfolk medium fine sand.
The plots were three corn rows wide with border rows sepa-
rating all plots. A general application of 400 pounds per acre
of a 0-4-4 fertilizer made from superphosphate and muriate of
potash was made in the row. Whatley's Prolific corn was the
variety grown. The entire field was divided into 13 blocks, each
of which contained four plots. Each of the following four treat-
ments was represented in each block, being allotted at random
to one of the four plots: (1) nothing; (2) 15 pounds per acre
of zinc sulphate applied separately in the drill before planting;
(3) 65 pounds per acre of urea as a side-dressing when the corn
was about half-grown; (4) 15 pounds per acre of zinc sulphate
in the row and the 65 pound-per-acre urea side-dressing when
the corn was half-grown. The average yields of the corn har-
vested from the plots have been calculated in bushels per acre
and are given in Table 7.
On the basis of the corn yields obtained with the 0-4-4 formula
without zinc sulphate, a side-dressing with urea as the source
of ammonia increased the grain yield 0.79 bushels per acre, while
15 pounds of zinc sulphate per acre increased the yield 2.65












TABLE 7.-EFFECT OF ZINC SULPHATE ON YIELD OF CORN FERTILIZED WITH A 0-4-4 MIXTURE AND SIDE-DRESSED WITH UREA.

Apparent
Corn Apparent Apparent increase
Urea and Zinc Sulphate Applications yield increase increase due to zinc
(in addition to the 400 pounds per acre of 0-4-4) bu. per due to zinc due to and Urea
acre sulphate Urea combined
Bu./A Bu./A Bu./A
None. (i.e. the 0-4-4 only) 9.29 .85"


15 pounds per acre zinc sulphate


65 pounds per acre urea side-dressing


15 pounds per acre zinc sulphate and
;5 pounds per acre urea side-dressing


11.94 .85 2.65


10.08 -+ .85


16.22 .85 6.14


Standard deviation, based on analysis of variance
L. S. D. -= 2.49 bu. per acre. (See Note)
NOTE: "Least significant difference", indicating the magnitude of difference required for odds of 19 : 1 that the "true"
difference is greater than zero: estimated by taking the product of the standard deviation of a difference and the appropri-
ate value of t. From R. A. Fisher's table.


0.79



4.28


6.93






The Use of Zinc Sulphate Under Field Crops


bushels, and the zinc sulphate and urea together increased the
yield 6.93 bushels. On the basis of the corn yields with the 0-4-4
formula with zinc sulphate, the side-dressing of urea increased
the yield 4.28 bushels per acre. On the basis of the corn yields
with the 0-4-4 formula without zinc sulphate plus the urea side-
dressing, the addition of zinc sulphate increased the yields 6.14
bushels per acre. These results emphasize the specificity of the
action of the zinc compound and the dependence of a favorable
action of one plant nutrient on the presence of an adequate
available supply of other required elements.
Rates of Application.-Two field experiments on the Experi-
ment Station farm serve to give an idea of the effect of various
rates of application of zinc sulphate on the yield of corn. One
of these tests was conducted on a field of Norfolk and Hernando
medium fine sands which had been cultivated annually for a
number of years until 1933, when it was allowed to lie fallow
to weeds and grasses. In the spring of 1934 the field was planted
to a number of field crops including corn. Zinc sulphate was
applied at the rates of 0, 5, 15 and 60 pounds per acre. Each
treatment was replicated six times.
Zinc sulphate applications were made in the row on March 29.
A 4-4-4 fertilizer, made from nitrate of soda, superphosphate
and muriate of potash, was applied in the row at the rate of 400
pounds per acre on March 31. The corn was planted on April 7,
and side-dressed with nitrate of soda at the rate of 100 pounds
per acre on May 31. The corn was harvested September 25.
In 1935, the zinc sulphate and fertilizers were applied at the same
rates to the same plots and the experiment repeated. The aver-
age yields of the six replicated plots for 1934 and 1935 have
been calculated in bushels of corn per acre and the results are
given in Table 8.
As may be observed from this table, five pounds of zinc sul-
phate per acre applied in the row brought a 31.47 percent increase
in the yield of corn in 1934. The higher amounts of zinc sulphate
did not materially increase the yield of corn over that obtained
with the five pounds per acre rate. Very few of the physical
symptoms of white bud were apparent in this field during the
1934 growing season.
During the 1935 growing season, plants on the plots receiving
no zinc sulphate showed definite physical symptoms of white
bud, especially during the early growth stages. The application
of five pounds of zinc sulphate per acre increased the corn yield






Florida Agricultural Experiment Station


38.05 percent. The 15 pound application increased the yield
49.94 percent and was thus definitely better than the smaller
application. The 60 pound application failed to increase the
yield over that obtained with the 15 pound application.

TABLE 8.-EFFECT OF VARYING AMOUNTS OF ZINC SULPHATE ON THE YIELD
OF CORN GROWN ON NORFOLK AND HERNANDO MEDIUM FINE SANDS.

19341 19352
Application of Zinc Sulphate |
per Acre Corn I Corn
yield I Increase yield Increase
Bu./A % Bu./A %

None 11.63 17.16

5 pounds 89% zinc sulphate 15.29 31.47 23.69 38.05

15 pounds 89% zinc sulphate 15.77 35.59 25.73 49.94
III
60 pounds 89% zinc sulphate 15.67 34.73 25.40 48.02


1 A general application of 400 lbs./A. of a 4-4-4 mixture was made.
2 Zinc sulphate and fertilizer were re-applied.

In 1935, an additional field of Norfolk and Hernando medium
fine sands was used to study two rates of application of zinc
sulphate. The field was divided into 50 plots, each of which
was 70 feet long and 19.67 feet wide. Whatley's prolific corn
was planted in 2.8 feet checks. Zinc sulphate was applied in
the row at two rates, 12 and 36 pounds per acre, four days before
a general application of 600 pounds per acre of a 2-4-4 mixed
fertilizer composed of nitrate of soda, superphosphate and
muriate of potash was made. The corn was planted five days
after the general fertilizer application. There were 10 plots
without zinc sulphate, and 20 each with 12 and 36 pounds per
acre. The plots were placed in randomized blocks.
Average yields per acre of corn are recorded in Table 9. Twelve
pounds of zinc sulphate per acre applied in the row increased
the yield of corn 11.03 bushels per acre, while 36 pounds increased
the yield 11.61 bushels. From these experiments on the rate
of application of zinc sulphate it appears that an economical rate
for these soil types lies between 10 and 20 pounds per acre.





The Use of Zinc Sulphate Under Field Crops


TABLE 9.-EFFECT OF VARYING AMOUNTS OF ZINC SULPHATE ON THE YIELD
OF CORN GROWN ON NORFOLK AND HERNANDO MEDIUM FINE SANDS.

Application of Zinc Sulphate per Acre Corn yield Increase

Bu.'A Bu.'A

None 12.70

12 pounds of 89% zinc sulphate 23.7: 11.0:

36 pounds of 89% zinc sulphate 24.31 11.;1

Note: A general application of 600 lbs., A. of a 2-4-4 mixture was made.

With Nitrate of Soda as a Side-Dressing.-Mixed fertilizers
are not used commonly on corn on the sandy soils of Florida.
Frequently the only fertilization that the corn receives is a side-
dressing of nitrate of soda or some other quickly available
nitrogenous material. In 1935, two tests were conducted on
sandy soils to determine the effect of applying zinc sulphate
under the corn before planting and side-dressing with nitrate
of soda.
A field in which white bud of corn had been very severe was
located near Lee, Madison County. The soil is a Norfolk fine
sand which has been kept in culture annually for a number of
years. White bud had developed so severely in previous years
that it was difficult to maintain an adequate stand of corn and
the yields were very low. Ten plots were laid out in the field.
The plots were 100 feet long and eight rows wide. Alternate
rows of each plot received an application of 22.7 pounds of zinc
sulphate per acre in the row before planting. Alternate plots
received a side-dressing of 110.4 pounds of nitrate of soda per
acre when the corn was about half grown. Average yields of
the variously treated plots calculated in bushels of corn per acre
are recorded in Table 10.
The yield of corn was increased from 2.39 bushels per acre
with no zinc sulphate or nitrate of soda to 14.70 bushels per
acre where 22.7 pounds of zinc sulphate was applied in the row
before planting. Side-dressings of nitrate of soda without zinc
sulphate increased the yield only slightly to 2.64 bushels, while
with zinc sulphate the yield was increased to 17.99 bushels per





Florida Agricultural Experiment Station


acre. Such exceptionally large increases in yield of corn follow-
ing the application of zinc sulphate may be expected only in
fields where the white bud condition is very severe.
TABLE 10.-EFFECT OF APPLYING ZINC SULPHATE UNDER CORN, AND SIDE-
DRESSING WITH NITRATE OF SODA. NORFOLK FINE SAND.

Yield of corn
Treatment Bu./A

No zinc sulphate or nitrate of soda 2.39

22.7 pounds of 89% zinc sulphate per acre 14.70

110.4 pounds nitrate of soda per acre 2.64

110.4 pounds nitrate of soda and 22.7 pounds 89%
zinc sulphate per acre 17.99

The other experiment on the use of zinc sulphate under corn
and side-dressing with nitrate of soda was in a field near La-
Crosse, Alachua County. The soil is a Hernando fine sand. The
field had been planted to corn in 1934, after having grown a
heavy crop of Crotalaria spectabilis in 1933. It had received a
general application of zinc sulphate at the rate of 15 pounds per
acre in 1934. In 1935, one row plots 600 feet long were used
in this field. Plots were established with no zinc sulphate and
no nitrate of soda, with 20 pounds of zinc sulphate per acre
applied in the row before planting, with 150 pounds per acre
of nitrate of soda as side-dressing when the corn was about four
feet high, and with zinc sulphate applied under the corn and
a side-dressing of nitrate of soda. Five replications of these
plots were made. The average yield of corn from the variously
treated plots has been calculated in bushels per acre and the
results are given in Table 11.
The zinc sulphate applied under the corn before planting
increased the yield 9.01 percent, nitrate of soda applied as a
side-dressing increased the yield 7.43 percent, while zinc sulphate
applied before planting and nitrate of soda used as a side-dressing
increased the yield 29.55 percent over the plots without fer-
tilizer. On this soil, the effective use of nitrate of soda as a
side-dressing depended upon the presence of an adequate supply
of zinc.





The Use of Zic Sulphate Under Field Crops


TABLE 11.-EFFECT OF APPLYING ZINC SULPHATE UNDER CORN AND SIDE-
DRESSING WITH NITRATE OF SODA. HERNANDO FINE SAND.

Corn yield Increase
Treatlmet -t
Bu. A
No zinc sulphate or nitrate of soda 24.09
20 pounds of 89%C zinc sulphate per acre 26.26 0.01
150 pounds of nitrate of soda per acre as
side-dressing 25.88 7.43

150 pounds of nitrate of soda and 20 pounds
89% zinc sulphate per acre 31.21 29.55

Effects of Separate and Combined Applications with Fertilizer
Mixtures Containing Superphosphate.-In addition to those out-
lined above, five other field tests using zinc sulphate were con-
ducted in 1934. One was on the Experiment Station Farm at
Gainesville and the others were on outlying farms. Not all fields
on which tests were made had shown symptoms of white bud,
but it was thought that some stimulation of plant growth might
be obtained even when the physical characteristics of the mal-
nutrition were not evident.
Each plot in these field trials consisted of eight rows of corn
20 feet long. Each of the treatments was quadruplicated in
every test. The plan of the tests was relatively simple. It in-
volved (1) the use of zinc sulphate with an inorganic fertilizer
mixture with a relatively high percentage of superphosphate;
(2) the use of zinc sulphate with the inorganic mixture contain-
ing no superphosphate; and (3) the use of a similar fertilizer
formula with the ammonia derived from organic sources without
additions of zinc sulphate. The treatments of the individual
plots in the tests are listed below:
Plot 1.-400 pounds per acre of a 4-8-4 mixture made from
nitrate of soda, superphosphate, and muriate of potash and 20
pounds per acre of 89 percent zinc sulphate.
Plot 2.-400 pounds per acre of the inorganic 4-8-4 mixture
without zinc sulphate.
Plot 3.-400 pounds per acre of a 4-0-4 mixture made from
nitrate of soda and muriate of potash, and 20 pounds of 89 per-
cent zinc sulphate.
Plot 4.-400 pounds per acre of the 4-0-4 inorganic mixture
without zinc sulphate.











TABLE 12.-AVERAGE YIELDS OF CORN GROWN IN 1934 WITH AND WITHOUT ZINC SULPHATE APPLICATION IN FIELDS FER-
TILIZED WITH A 4-8-4 INORGANIC MIXTURE AND A 4-0-4 INORGANIC MIXTURE IN COMPARISON WITH THOSE GROWN WITH
A 4-8-4 WITH ORGANIC AMMONIATES.


Bushels of Corn Per Acre


Location and Soil Types



Gainesville. Norfolk and
Hernando medium fine sand.


LaCrosse.
Bladen fine sand.


Madison.
Norfolk fine sand.


Branford.
Norfolk medium fine sand.


Gainesville.
Blanton fine sand.


Notes on White Bud
Condition and Management
of Fields Before 1934


Severe white bud in 1932.
Field fallowed to weeds
and grass in 1933.

Severe white bud in 1932
and 1933. Field cropped
each year.

Severe white bud in 1932
and 1933. Field cropped
each year.

No white bud in 1933. Field
cropped for several years.


No white bud in 1933.
Land cleared of natural
vegetation in 1932.


-----------


4-8-
Notes on White Bud +
Condition in 1934 ZnSI


Very little evidence of
white bud. 20.2

Plots without zinc sulphate
or organic ammoniates
showed white bud in early 26.7
growth stages.
Plots without zinc sulphate
or organic ammoniates
showed white bud in early 17.C
growth stages.


No white bud. 20.A



No white bud. 22.4


4-0-4 4-8-4
I Organ.
am-
monia


19.64 22.64



20.99 23.15



15.69 12.08



19.81 20.22



16.26 26.51


4-8-4 4-0-4
+
ZnSO4



20.77 21.75



23.04 26.89



16.26 19.95



20.78 20.37



24.30 21.46





The Use of Zinc Sulphate Under Field Crops


Plot 5.--400 pounds per acre of a 4-8-4 mixture made from
fish scrap, cottonseed meal, superphosphate and muriate of
potash.
The zinc sulphate was mixed with the fertilizers and applied
in the drill row a week or 10 days before planting. At harvest
the corn was shucked from the stalks in the field and the weights
were taken. The average yield of the quadruplicated plots has
been calculated in bushels of corn per acre and the results are
given in Table 12.
Using the yields obtained with the inorganic fertilizer mix-
tures with and without zinc sulphate, several interesting cal-
culations may be made. The bushels increase or decrease of
corn yields apparently due to superphosphate with and without
zinc sulphate, and the bushels increase or decrease apparently
due to zinc sulphate with and without superphosphate have been
calculated and the results are given in Table 13.
From these results it appears that the superphosphate gave
a slightly increased corn yield when not used with the zinc sul-
phate in all five fields. Considering the possible error of this
type of experimentation, the response in four of the five fields
is probably not significant. However, in one field (Blanton fine
sand at Gainesville) where the land had been cleared recently,
the application of superphosphate gave a positive response of
8.04 bushels per acre when used without zinc sulphate, and only
1.00 bushel per acre when used with zinc sulphate. The other
fields gave decreased corn yields when the zinc sulphate was
applied mixed directly with the inorganic mixture containing
8 percent P20; as superphosphate when compared with the yields
obtained with the 4-8-4 inorganic mixture without zinc sulphate.
Zinc sulphate when applied with the inorganic mixture con-
taining superphosphate gave an increased yield in only two of
the fields. However, when used with the mixture without super-
phosphate, zinc sulphate increased the yields of corn in all the
fields.
Average increases or decreases in corn yields in the five ex-
periments emphasize the relationship between the response to
superphosphate and zinc sulphate when applied in the intimate
contact of inorganic fertilizer mixtures distributed in the row.
The average phosphate response amounted to 2.55 bushels per
acre when applied without zinc sulphate, while a decrease of
0.71 bushels per acre was obtained with zinc sulphate applied
in the mixture. Conversely, with these inorganic mixtures the











TABLE 13.-BUSHELS INCREASE OR DECREASE IN YIELD OF CORN GROWN IN 1934 ON PLOTS FERTILIZED WITH AN INORGANIC
4-8-4 MIXTURE AND AN INORGANIC 4-0-4 MIXTURE WITH AND WITHOUT ZINC SULPHATE.
Phosphate Response Zinc Response
With Without With Without
Location and Soil Type zinc zinc super- super-
sulphate sulphate phosphate phosphate
Bu./A Bu./A Bu./A Bu./A

Gainesville. Norfolk and Hernando medium fine sand. -1.53 +1.10 -0.55 +2.11


LaCrosse. Bladen fine sand. -0.10 +2.05 +3.75 +5.90


Madison. Norfolk fine sand. -2.93 +0.57 +0.76 +4.26


Branford. Norfolk medium fine sand. I 0.01 +0.97 -0.42 +0.46


Gainesville. Blanton fine sand. +1.00 +8.04 -1.84 +5.20


Average -0.71 +2.55 +0.34 +3.59

Negative sign (-) denotes decrease in yield.






The Use of Zinc Sulphate Under Field Crops


zinc response was only 0.34 bushels per acre increase with
superphosphate and 3.59 bushels per acre increase without super-
phosphate.
It has been shown in Table 13 that superphosphate interferes
with the zinc response and vice versa when the two materials
are mixed together in the mineral mixture before application
to the field. An obvious suggestion is that this mutual inter-
ference is due to the formation of the very insoluble zinc phos-
phate, thus withholding more or less of both elements from
solution.
These observations suggested the possibility that there might
be no interference if the zinc sulphate was applied separate from
the mixture containing superphosphate; and also, that an or-
ganic source of nitrogen, such as cottonseed meal, might suffi-
ciently separate the zinc sulphate and superphosphate to prevent
their combination to form insoluble compounds.
The following 10 treatments were designed to answer these
questions and to prevent any ambiguity in the results arising
from the natural zinc and phosphorus content of the cottonseed
meal. Superphosphate and muriate of potash were the sources
of phosphorus and potassium used.
SYSTEM OF TREATMENTS
NH,
Nitrogen f% from nitrate of
NHI-P.O,-K,O at 400 lbs. per acre from soda I
plus zinc sulphate (where designat- nitrate of soda 14 from cotton-i
ed) at 20 pounds per acre Treatment No. [ seed meal
Treatment No.
4-8-4 plus zinc applied separately.. 1 6
4-8-4 plus zinc in mixture... 2 7
4-8-4 w without zinc ................... ..... 8
4-0-4 plus zinc in mixture...... 4 9
4-0-4 without zinc .. ..... ............5 10

These treatments were applied in two field experiments in
1935; one at LaCrosse and one near Gainesville.
The experiment at LaCrosse was in a field adjacent to the one
used for the 1934 test. The soil is a Bladen fine sand. Corn
grown in the field previously had been affected more or less
severely with white bud. The field was divided into plots 40
by 20 feet. Each of the 10 different fertilizer applications was
replicated on 10 plots in the experiment. The plots were ar-






Florida Agricultural Experiment Station


ranged in a Latin square. The fertilizer mixtures were applied
in the drill on March 18, and covered with a plow. The separate
zinc sulphate applications were made on March 20, and Whatley's
Prolific corn was planted on March 23. The corn was given the
same cultivation over the entire field. Weights of husked corn
were obtained in September.
TABLE 14.-AVERAGE YIELDS OF CORN GROWN IN 1935 WITH AND WITHOUT
ZINC SULPHATE IN FIELDS FERTILIZED WITH A 4-8-4 AND A 4-0-4 FER-
TILIZER MIXTURE.

SLaCrosse Gainesville
Fertilizer and Zinc Sulphate Applications
Bu./A Bu./A

INORGANIC MIXTURES1

400 pounds of 4-8-4 with 20 pounds zinc sulphate
applied separately 36.15 37.80

400 pounds of 4-8-4 with 20 pounds zinc sulphate
mixed before application 33.94 35.68

400 pounds of 4-0-4 with 20 pounds zinc sulphate
mixed before application 33.69 32.93

400 pounds of 4-8-4 28.34 34.77
I I
400 pounds of 4-0-4 26.29 32.30
ORGANIC MIXTURES2

400 pounds of 4-8-4 with 20 pounds of zinc sulphate
applied separately 35.19 37.79

400 pounds of 4-8-4 with 20 pounds of zinc sulphate
mixed before application 34.80 37.99

400 pounds of 4-0-4 with 20 pounds of zinc sulphate
mixed before application 35.53 33.57

400 pounds of 4-8-4 1 29.20 34.00

400 pounds of 4-0-4 29.14 30.77
1 Made from nitrate of soda, superphosphate and muriate of potash.
2 Made from cottonseed meal, nitrate of soda, superphosphate and muriate
of potash.
Least Significant Difference (See Note, Table 7): LaCrosse, 3.30
bu./A; Gainesville, 2.50 bu./A.

The experiment at Gainesville was on a Blanton fine sand.
Corn grown previously in the field had shown some symptoms
of white bud. The field was divided into 160 plots, each of which






The Use of Zic Sulphate ul'der Field C'rops 33

was 70 feet long and 22.5 feet wide. Each of the 10 fertilizer
applications was replicated on 16 plots in the field. Thus there
were 16 randomized blocks of plots for the 10 fertilizer mixtures.
The fertilizer was applied in the drill on March 20 and covered.
The separate applications of zinc sulphate were made on March
21 and Whatley's Prolific corn was planted on March 26. The
husked corn from each of the plots was weighed in September.
Average yields of corn in these experiments have been cal-
culated in bushels per acre and the results are given in Table 14.
The responses of the corn to the application of superphosphate
and zinc sulphate have been calculated as previously and the
results are given in Table 15.
TABLE 15.-INCREASE OR DECREASE IN YIELDS OF CORN GROWN IN 1935
WITH 4-8-4 AND 4-0-4 FERTILIZER MIXTURES WITH AND WITHOUT ZINC
SU-LPHATE.


Phosphate Response


Location of
Experiment





LaCrosse


Gainesville


Average


Zinc Response


With With Separate Mixed
zinc 1 zinc Without from with Without
sulphate sulphate zinc super- super- super-
eparate mixed sulphate phosphate phosphate phosphate
bu./A bu./A bu./A bu./A bu./A bu./A
INORGANIC MIXTURES

-2.46 +0.25 +2.05 +7.81 +5.60 +7.40


+4.87 +2.75 +2.47 +3.03 +0.91 +0.63


3.66 +1.50 +2.26
-3.66 +1.50 +2.26 -5-.42 '+3.25 +4.01


ORGANIC MIXTURES

-0.34 -0.73 +0.06


+4.22 +4.42 +3.23


+1.94 +1.84 +1.64


+5.99 +5.60


+3.79 +3.99


-4.89 +4.79


Least significant differences (See Note, Table
per acre. Gainesville, 2.50 Bu. per acre.


7): LaCrosse, 3.30 Bu.


The results obtained with inorganic mixtures substantiate
essentially those of the previous season. The response of corn
to the application of superphosphate was greater without zinc
sulphate than with zinc sulphate at LaCrosse and practically


LaCrossee


Gainesville


Average


+ 6.30


+2.80






Florida Agricultural Experiment Station


the same at Gainesville. The separate zinc sulphate applications
gave the largest phosphate response in both experiments. In
keeping with these results, the zinc response at LaCrosse was
greater without than with the intimate admixture of super-
phosphate. The plots with superphosphate but with zinc sul-
phate applied separately gave the largest comparative increases
in corn yields, apparently due to zinc in both experiments. Thus
the response of corn to both phosphate and zinc fertilization
was greatest when the zinc sulphate was applied separately from
the inorganic mixtures containing superphosphate.
The use of cottonseed meal apparently overcame the mutual
depressing effect of superphosphate and zinc sulphate on one
another, as there are very small differences in either the phos-
phate or zinc response when one-fourth of the nitrogen of the
mixtures was supplied from cottonseed meal. From the results
obtained in 1934 and 1935, it may be concluded that the intimate
admixture of zinc sulphate with inorganic fertilizers containing
relatively high percentages of superphosphate may not give the
maximum results to be expected from these materials. The use
of cottonseed meal as a source of part of the nitrogen in the
fertilizer, apparently largely eliminates the mutual interference
of superphosphate and zinc sulphate.
No experimental evidence has been obtained on the results
which may be expected from side-dressing chlorotic corn plants
with zinc sulphate. Observations in fields which had been side-
dressed with zinc sulphate when the corn was two to four feet
high indicate that this method of application may cause some
improvement in the chlorotic condition but will not give as sat-
isfactory results as the drill application before planting.
Residual Effect.-Preliminary results indicate that a residual
effect may be expected on some soils from the application of zinc
sulphate in the row. Observations were made in a field which
had had an application of 12 pounds of zinc sulphate per acre
in the row in 1934. In 1935 part of this field was left untreated
while part had an additional application of zinc sulphate in the
row before planting. The corn rows were placed in practically
the same location in 1935 as in 1934. The corn on the plots
which received zinc sulphate only in 1934 made a satisfactory
growth and showed no symptoms of white bud, and appeared
as healthy as those receiving the additional application of zinc
sulphate in 1935. The soils in this field are Norfolk and Her-
nando medium fine sands.





The Use of Zinc Sulphate Under Field Crops


EXPERIMENTS ON THE USE OF ZINC SULPHATE UNDER
OTHER FIELD CROPS
Peanuts.-In 1934, in conjunction with the corn tests using
inorganic fertilizer mixtures with relatively high percentages
of superphosphate and with no superphosphate, with and without
additions of zinc sulphate, a series of tests was conducted with
peanuts. The fertilizers were mixed and applied in the row
as described for the field tests with corn. Spanish, Florida run-
ner and Virginia jumbo runner peanuts were compared in one
row plots which were quadruplicated in each field. At maturity
the peanuts were harvested and the weights of the nuts deter-
mined. Weights of nuts from the plots have been calculated
in pounds of dry nuts per acre and the results are given in
Table 16.
The yield data obtained in these preliminary experiments with
different varieties of peanuts give some indication of the results
which may be expected from the use of zinc sulphate under this
crop. Results with Spanish peanuts show that when zinc sul-
phate was used with a 4-8-4 inorganic mixture, yields of nuts
were increased over those obtained with the 4-8-4 without zinc
sulphate in three of the experiments. The increase due to zinc
sulphate obtained at LaCrosse on Bladen fine sand was large
enough to be definitely significant. Also, when used with a
4-0-4 inorganic mixture, the yield of nuts was increased by zinc
sulphate over that obtained with the 4-0-4 mixture without
zinc sulphate in three experiments. Two of these increases,
the one at LaCrosse and the one at Branford, are large enough
to be significant, considering the variations in plots to be expect-
ed in this type of experimentation. The 4-8-4 inorganic mixture
with zinc sulphate gave the highest yields of Spanish peanuts
in the experiment at LaCrosse but the increase over those ob-
tained with the 4-0-4 inorganic mixture with zinc sulphate was
small and insignificant. The 4-0-4 inorganic mixture with zinc
sulphate gave the highest yields at Gainesville on Norfolk and
Hernando medium fine sands and at Branford on Norfolk medium
fine sand. The 4-8-4 mixture with the nitrogen from cottonseed
meal and fish scrap gave the highest yield of nuts at Gainesville
on Blanton fine sand.
With Florida runner peanuts, the 4-8-4 inorganic mixture with
zinc sulphate gave significantly higher yields than the 4-8-4
without zinc sulphate at Gainesville on Norfolk and Hernando
medium fine sands, and at LaCrosse on Bladen fine sand. The






TABLE 16.-AVERAGE YIELD OF DRIED PEANUTS GROWN WITH AND WITHOUT ZINC SULPHATE APPLICATIONS IN FIELDS WITH
COMPLETE AND INCOMPLETE FERTILIZER MIXTURES.


Location and Soil Types



Gainesville. Norfolk and
Hernando medium fine sands.
LaCrosse.
Bladen fine sand.
Branford.
Norfolk medium fine sand.
Gainesville.
Blanton fine sand.

Gainesville. Norfolk and
Hernando medium fine sands.
LaCrosse.
Bladen fine sand.
Branford.
Norfolk medium fine sand.
Gainesville.
Blanton fine sand.


Gainesville. Norfolk and
Hernando medium fine sands.
LaCrosse.
Bladen fine sand.
Branford.
Norfolk medium fine sand.
Gainesville.
Blanton fine sand.


Pounds of Dry Peanuts per Acre


SNotes on White Bud Condition and
Management of Fields Before 1934


4-8-4
ZnSO
ZnSO,


SPANISH PEANUTS
ISevere white bud in 1932. Field fallowed
to weeds and grass in 1933. 510.7
Severe white bud in 1932 and 1933.
Field cropped each year. 322.7
No white bud in 1933.
Field cropped for several years. 221.1
No white bud in 1933.
SLand cleared of native vegetation in 1932. 141.6


FLORIDA RUNNER PEANUTS
Severe white bud in 1932. Field fallowed
to weeds and grass in 1933.
Severe white bud in 1932 and 1933.
Field cropped each year:
No white bud in 1933.
Field cropped for several years.
No white bud in 1933.
Land cleared of native vegetation in 1932.
VIRGINIA JUMBO RUNNER PEANUTS
Severe white bud in 1932. Field fallowed
to weeds and grass in 1933.
Severe white bud in 1932 and 1933.
Field cropped each year.
No white bud in 1933.
Field cropped for several years.
SNo white bud in 1933.
ILand cleared of native vegetation in 1932.


1150.0

433.0

464.0

184.0
z ~~ I


4-8-4




528.5

277.9

194.9

138.3


956.0

358.0

482.0

330.0


4-0-4
+Zn
ZnSO8


4-0-4 4-8-4
Organic
ammonia


559.5 553.2 548.8

320.4 225.4 284.1

226.5 162.3 | 216.7

60.9 71.9 208.0


895.0

370.0

455.0

139.0


860.0

308.0

327.0

90.0


1103.0

393.0

407.0

164.0


1522.0 1111.5 1217.5 1148.9 1586.3

475.0 359.0 377.0 298.0 458.0

504.0 519.0 446.0 327.0 351.0

154.0 233.0 47.8 25.5 114.0


20 pounds per acre of 89% zinc sulphate were mixed with 400 pounds per acre of the inorganic mixture.





The Use of Zinc Sulphate Under Field Crops


4-0-4 inorganic mixture with zinc sulphate gave significantly
higher yields than the 4-0-4 without zinc sulphate in the four
experiments.
With Virginia jumbo runner peanuts, zinc sulphate applied
with the 4-8-4 inorganic mixture gave significant increases in
nut yields over the 4-8-4 mixture alone at Gainesville on Norfolk
and Hernando medium fine sands and at LaCrosse on Bladen
fine sand. The 4-0-4 inorganic mixture with zinc sulphate gave
significantly higher yields than the 4-0-4 alone in the four ex-
periments.
The yield data of these preliminary tests may be summarized
for the three varieties of peanuts grown in the four fields with
the five different fertilizer combinations. Considering first the
data obtained with the 4-8-4 inorganic fertilizer mixture, with
and without zinc sulphate, it is observed that the 4-8-4 mixture
with zinc sulphate gave higher nut yields in seven of the 12
combinations. Six of these increases may be considered as sig-
nificant. In the other five combinations, the 4-8-4 inorganic
mixture without zinc sulphate gave higher yields than the same
mixture with zinc sulphate. Only two of these increases were
large enough to be considered significant in view of the variation
in the yields of the plots.
The yields obtained with the 4-0-4 inorganic mixture with
and without zinc sulphate under the different peanut varieties
in the four fields show an increase due to zinc sulphate in 11
of the 12 combinations. In 10 of the combinations the yields
may be considered as significantly higher where the zinc sulphate
was used. The yield was higher from the 4-0-4 inorganic mix-
ture plots without zinc sulphate in only one combination. Spanish
peanuts on Blanton fine sand at Gainesville.
In a comparison of yield data from all the various combina-
tions, the 4-8-4 inorganic mixture with zinc sulphate produced
the highest nut yield in four tests, and the same mixture without
zinc sulphate produced the highest yields in four tests. The
4-0-4 inorganic mixture with zinc sulphate gave the highest
yields in two tests. The 4-8-4 mixture with the nitrogen from
cottonseed meal and fish scrap produced the highest yield of
nuts in two tests.
From these results it may be concluded that the nut yield
of peanuts may be increased in some instances by the application
of zinc sulphate in the row before planting. However, the re-
sponse of the peanut to the application of zinc sulphate is neither





Florida Agricultural Experiment Station


as striking nor as consistent as that obtained with corn. No
physical symptoms of malnutrition were observed in any of the
peanut experiments regardless of the severity of white bud in
corn on adjacent plots.
Oats.-Zinc sulphate was used under oats in a field test on
the Station farm at Gainesville. Oats were planted in drill rows
in a field which had grown chlorotic corn for several years. Zinc
sulphate was applied at three rates, 20, 40, and 80 pounds per
acre, between the drill rows in one series of plots and in the
drill row in another. The applications were made on December
15, 1933, and the oats were planted the same day. The oats
were top-dressed with nitrate of soda at the rate of 150 pounds
per acre on February 20.
TABLE 17.-YIELD OF OAT SHEAVES FOLLOWING APPLICATIONS OF ZINC
SULPHATE TO THE SOIL.

Pounds of Zinc Sulphate per Acre
Method of Application
0 20 40 80
lbs./A lbs./A lbs./A lbs./A
Applied between drills 484 770 918 1271

Applied in drills 410 1124 965 883

Average 447 947 941 1077

NOTE: The oats were top-dressed with nitrate of soda.

Even in the seedling stage, the oats were healthier and larger
on the plots receiving applications of zinc sulphate. However,
the plants on the plots receiving no zinc sulphate did not show
any specific symptoms of malnutrition such as shown by corn.
Oats growing on plots receiving applications of zinc sulphate
matured approximately two weeks before those on plots without
zinc sulphate. Weights of the dried oats were taken in June.
Yields have been calculated in pounds of oats in the sheaf per
acre and the results are given in Table 17. Figure 10 shows
photographs of typical oat seedlings removed from the check
plots and from the plots receiving zinc sulphate applications.
The average yield of oats was more than doubled by the appli-
cation of zinc sulphate. As the plots were not sufficiently
replicated to give thoroughly reliable data, the favorable response




The Use of Zinc Sulphate Under Field Crops


of oats may be considered only suggestive of what may be ex-
pected from the application of zinc sulphate to oats in fields
producing white bud of corn.


IVNUL


Fig. 10.-Typical oat plants removed from plots with (right) and without
(left) zinc sulphate applications to the soil.
Velvet Beans.-An experiment on the use of zinc sulphate
under velvet beans was conducted on the Experiment Station
farm in 1934 and 1935. The field in which the test was con-
ducted had been cropped annually until 1933, when it was allowed
to remain fallow to volunteer weeds and grasses. White bud
of corn had developed severely over practically the entire field
during the last few years that the field had been in culture.
The soils are Norfolk and Hernando medium fine sands.
Three rates of zinc sulphate, 5, 15 and 60 pounds per acre,
were applied in the rows on March 29, 1934. A general applica-
tion of 400 pounds per acre of a 4-4-4 fertilizer mixture made
from nitrate of soda, superphosphate and muriate of potash
was applied in the rows a few days later. Each of the treat-
ments was replicated six times.
Velvet beans were planted on April 9 and the green weights
of the top growth of the plots were measured when the plants
had reached their maximum growth in August.





Florida Agricultural Experiment Station


Similar zinc sulphate and fertilizer applications were made
to the same plots in the field in 1935. The zinc sulphate was
applied in the row on March 19, the fertilizer on March 23, and
the velvet beans planted on April 6. The green top growth of
the velvet beans of the different plots was harvested upon reach-
ing its maximum. Average green weights of the top growth
on the plots have been calculated in pounds per acre and the
results are given in Table 18.
TABLE 18.-YIELDS OF GREEN TOP GROWTH OF VELVET BEANS AS AFFECTED
BY THE APPLICATION OF ZINC SULPHATE WITH FERTILIZER IN THE ROW
BEFORE PLANTING.
1934 19351
Application of Zinc Sulphate Yield Increase [ Yield Increase
per Acre
bu./A % bu./A | %
None 26,569 17,749

5 pounds 89%C zinc sulphate 26,685 0.44 20,944 18.00

15 pounds 89% zinc sulphate 27,286 2.69 21,399 20.56

60 pounds 89% zinc sulphate 27,547 3.68 19,584 10.34

1Zinc sulphate and fertilizer re-applied.

The yield of green top growth of velvet beans was not affected
appreciably by the application of zinc sulphate in 1934, but in
1935 all rates of application of zinc sulphate increased the yield.
In 1934, the velvet bean plants did not show any symptoms
of malnutrition when grown on the plots receiving no zinc sul-
phate. In this connection it should be recalled that the field
in which this experiment was conducted had been fallowed to
volunteer weeds and grasses in 1933, and that this program has
been shown definitely to decrease the severity of white bud of
corn. However, in 1935, when the velvet beans were about two
to three weeks old, the plants growing on the plots without zinc
sulphate began to show definite symptoms of malnutrition. The
plants in the plots treated with zinc sulphate remained healthy
and made vigorous growth.
The first stages of injury to the leaves is characterized by the
development of a general bronze or reddish brown color over
the leaf. This is followed by distinct yellowing between the
veins of the leaves and the development of small areas of dead






The Use of Zinc Sulphate Under Field Crops


tissue. Finally the dead areas between the veins enlarge to
include practically all of the tissue and the edges of the leaf
die and curl up or fall away. At this stage, the affected leaves
often fall from the plant and may be followed by apparently
healthy green leaves which never show signs of malnutrition.
Several weeks were required for the full development of the
injury and subsequent recovery of the plants. The plants on
the plots without zinc sulphate were apparently healthy when
harvested but were stunted in growth. Leaves of the velvet
bean plants growing in the plots without zinc sulphate as com-
pared to a healthy green leaf from a plot receiving zinc sulphate
are illustrated in the photograph of Figure 11. This type of
injury to velvet beans has been observed frequently in Florida
in corn fields where severe symptoms of white bud are prevalent.





















Fig. 11.-Leaves of velvet bean plants removed from a plot without
zinc sulphate compared with a healthy leaf (lower left) from a plot with
zinc sulphate.

Cowpeas.-In 1934 and 1935 an experiment with Whippoorwill
and Suwannee cowpeas was conducted in the same field in a
similar manner as described for velvet beans. The average yields
of green top growth harvested at maximum development have
been calculated in pounds per acre and the results are given
in Table 19.














TABLE 1.-YIELDS OF GREEN TOP GROWTH OF COWPEAS IN POUNDS PER ACRE AS AFFECTED BY THE APPLICATION OF ZINC
SULPHATE WITH FERTILIZER IN THE ROW BEFORE PLANTING.


19351


Application of Zinc Sulphate
per Acre



None


5 pounds of 89% zinc sulphate


15 pounds of 89% zinc sulphate


60 pounds of 89% zinc sulphate

1Zinc sulphate re-applied.
(2) Decrease.


Whippoorwill
cowpeas
Yield Increase
lbs./A %


2,175


2,039


2,230


4,208


Yi
lbs


Suwannee
cowpeas
eld I Increase |
./A J %
I


Whippoorwill
cowpeas
Yield | Incre
lbs./A %


8,715 12,385


(2) 8,329 i (2) 12,826


2.53 9,374 7.56 14,569


93.47 10,777 23.66 14,331
!


ase


3.56


17.63


15.71


Suwannee
cowpeas
SYield Increase
I lbs./A %

11,848


13,277 12.06


13,881 17.16


13,776 16.27





The Use of Zinc Sulphate Under Field Crops


In 1934, the yields of green top growth of the cowpeas were
not significantly increased by either 5 pounds or 15 pounds of
zinc sulphate per acre. However, the 60 pounds per acre appli-
cation increased the yield of the Whippoorwill from 2,175 pounds
of green top growth per acre to 4,208 pounds per acre, or 93.47
percent. The yield of the Suwannee cowpea was increased from
8,715 pounds of green top growth per acre to 10,777 pounds,
or 23.66 percent, by 60 pounds per acre of zinc sulphate.
Following the application of zinc sulphate in 1935, the yields
of green top growth of the Whippoorwill cowpeas were increased
3.56, 17.63 and 15.71 percent respectively by the 5, 15 and 60
pounds per acre rates. The Suwannee cowpea yields were in-
creased 12.06, 17.16 and 16.27 percent respectively by these three
rates of application of zinc sulphate.





















Fig. 12.-Leaves of cowpea plants removed from a plot without zinc
sulphate compared with a healthy leaf (at the left) from a plot with
zinc sulphate.

In 1934, as with the velvet beans, no physical symptoms of
malnutrition were observed in the cowpeas. The plants appeared
to be healthy in all the plots. During the 1935 season definite
symptoms of malnutrition developed in the cowpea plants on the
plots without zinc sulphate. These symptoms began to appear
two to three weeks after the germination of the peas. Different












TABLE 20.-YIELDS OF GREEN TOP GROWTH OF PEARL MILLET IN POUNDS PER ACRE AS AFFECTED BY THE APPLICATION OF
ZINC SULPHATE WITH FERTILIZER IN THE ROW BEFORE PLANTING.
1934 19351
Application of Zinc Sulphate 1st Cutting I 2nd Cutting Total 1st Cutting 2nd Cutting Total
per Acre Yield Increase I Yield Increase Yield Increase Yield I Increase Yield Increase Yield Increase
bu./A| % Ibu./AI % Ibu./A[ % bu./Aj % Ibu./AI % Ibu./AI %
None 16,344 9,670 26,014 27,126i 8,793 35,919
..1I 3 2
5 pounds of 89% zinc sulphate 17,6881 8.22 10,527 8.86 28,215 8.46 34,923 28.74 9,394 6.83 44,317 23.38

15 pounds of 89% zinc sulphate 18,687 14.33 9,641 (2) 28,328 8.89 36,387 54.07 9,316 5.95 45,703 27.24

60 pounds of 89% zinc sulphate 20,235 23.81 9,874 2.11 30,109 15.74 36,875 56.92 10,2591 16.67 47,134 31.22

1 Zinc sulphate and fertilizer re-applied.
(2) Decrease.





The Use of Zinc Sulphate Under Field Crops


stages of the injury to cowpea leaves as compared to a leaf
removed from a plant receiving an application of zinc sulphate
are illustrated in Figure 12.
First, small brown spots developed on the leaves. As the
symptoms became more pronounced, the leaf tissue between the
veins became yellow and the brown spots enlarged or died com-
pletely. The area along the veins remained green. Finally the
tissue in the brown spots died completely and the leaves had a
dull yellow cast throughout. Often the edges of the leaves were
dead and crinkled. These leaves fell from the plant and were
replaced by healthy foliage. About three weeks were required
for the full development of the advanced symptoms of malnu-
trition in the cowpeas. During this period, there was a sharp
line of demarcation between the plants on the plots without
zinc sulphate and those with zinc sulphate. The plants in the
plots receiving the three rates of application of zinc sulphate
remained healthy and vigorous in contrast to the diseased con-
dition of the plants without zinc sulphate. After the advanced
stage of injury was reached, the cowpea plants dropped most
of the diseased leaves and put on an apparently healthy growth.
At harvest the cowpea plants receiving no zinc sulphate ap-
peared to be healthy but were stunted in growth as is indicated
by the yields of top growth. The development of the injury
was equally severe in the Whippoorwill and Suwannee peas. This
type of injury to cowpeas has been observed quite generally in
fields where white bud of corn is prevalent.
Pearl Millet.-In 1934 and 1935, Pearl millet was included in
the same field experiment described for velvet beans and cow-
peas. The average yields of green top growth of two cuttings
of Pearl millet from six replicated plots for each treatment have
been calculated in pounds per acre and the results are given in
Table 20.
In 1934, the yields of green top growth of the first cutting of
Pearl millet were increased 8.22, 14.33 and 23.81 percent re-
spectively by the 5, 15 and 60 pound rates of application of zinc
sulphate. The yields of the second cutting were not significantly
affected by the zinc sulphate in 1934. When the zinc sulphate
was re-applied in 1935, the yields of green top growth of the
first cutting were increased 28.74, 54.07 and 56.92 percent re-
spectively by the 5, 15 and 60 pounds per acre rates of applica-
tion. The yields of the second cutting were increased 6.83, 5.95
and 16.67 percent respectively by these rates.






Florida Agricultural Experiment Station


Fig. 13.-The effect of zinc sulphate on the growth of Pearl millet on
Norfolk medium fine sand. Right: No zinc sulphate; left: 60 pounds of
89 percent zinc sulphate per acre applied in the row before planting.


Fig. 14.-Leaves of Pearl millet removed from a plot without zinc sul-
phate compared with a healthy leaf from a plot with zinc sulphate. Healthy
leaf on the extreme left; the other seven leaves show progressive stages
of development of the chlorosis of millet.





The U.c of Zihc Slidphatch Utde Field Crops


No physical symptoms of malnutrition were observed in the
Pearl millet plants in 1934. In 1935, millet plants in the plots
without zinc sulphate began to show definite symptoms of chlo-
rosis when they were about four weeks old. The injury became
progressively more severe and definitely limited the growth of'
the millet as may be seen from Figure 13. Different stages of
chlorosis in the millet leaves as compared with a healthy leaf
are illustrated in Figure 14. As may be observed from this
photograph, the symptoms of the chlorosis of the millet are
similar in many respects to those of white bud of corn.
Pearl millet plants growing on plots treated with zinc sulphate
remained healthy and produced satisfactory yields. As may be
seen from Figure 13, the line between the zinc sulphate treated
plots and the plots without zinc sulphate was very sharp. Few
if any definite signs of the chlorosis appeared in any of the plots
with the three rates of zinc sulphate application.
Miscellaneous Field Crops.-In 1934 and 1935, experiments
on the application of zinc sulphate under several other field
crops were conducted in the same field and in conjunction with
the tests with velvet beans, cowpeas and Pearl millet. As none
of the plants showed any definite symptoms of chlorosis or
malnutrition, they have been grouped together for discussion.
In 1934, the three rates of application of zinc sulphate, 5, 15
and 60 pounds per acre, were made in the row before planting,
and followed by a general application of a 4-4-4 fertilizer mix-
ture made from nitrate of soda, superphosphate and muriate
of potash. Each of the treatments was replicated on six plots
in the field. The non-leguminous plants were side-dressed with
nitrate of soda when needed. Cayana sugarcane, Simpson
sugarcane, Napier grass, Texas seeded ribbon cane, Crotalaria
striata, Crotalaria spectabilis and Crotalaria intermedia were
planted in 1934.
In 1935, the zinc sulphate and fertilizer applications were
repeated and the crops again planted. Unfortunately, cold killed
the sugarcane in the winter of 1934. Unsatisfactory stands of
several of the other crops were obtained, so that only results
for Napier grass and sorghum are reported for this last season.
Weights of green tops were taken when the plants had made
their maximum growth. The average weights from the plots
have been calculated in pounds per acre and the results are given
in Table 21.








TABLE 21.-YIELDS OF GREEN TOP GROWTH OF MISCELLANEOUS FIELD CROPS AS AFFECTED BY THE APPLICATION OF ZINC
SULPHATE WITH FERTILIZER IN THE ROW BEFORE PLANTING.
1934


Crops Planted


Cayana sugarcane

Simpson sugarcane

Napier grass, 1st cutting

Napier grass, 2nd cutting

Sorghum (Texas seeded ribbon cane)

Sorghum, 2nd cutting

Crotalaria striata2

Crotalaria spectabilis

Crotalaria intermedia2


Napier grass

Sorghum (Texas seeded ribbon cane)
(1) Decrease.
2 These tests are not as reliable as the others because
3 Zinc sulphate and fertilizer re-applied.


Pounds 89
Appli
o 5
Ib./A b../

57,600 64,5

12,700 14,6

34,868 39,7

46,635 51,8

24,457 24,0

3,142 3,5

18,800 19,7

16,602 17,2

6,296 9,6
19353

76,134 83,5

10,033 9,6


% zi
ed p


A

00

10

18

65

22

46

'99

;53

09


86

67


inc Sulphate
er Acre
15 60
Ib./A Ilb./A

73,950 79,300

14,740 16,320

40,900 43,357

53,680 53,678

25,500 24,155

3,668 3,575

20,639 19,410

20,090 22,808

10,507 10,727


88,342

10,251


91,473

9,322


of an uneven stand.


5
%

11.97

15.04

13.91

11.21

(1)

12.86

5.31

3.92

52.62


Increase
15
%

28.38

16.06

17.29

15.11

4.26

16.74

9.78

21.00

66.88


60


37.67

28.50

24.34

15.10

(1)

13.78

3.24

37.38

70.38


20.15

(1)


9.79 16.03

(1) 1.18





The Usc of Zinc Sdlphate (Uwfcr Field Crops


In 1934, the sugarcanes, Napier grass. Crotalaria spectabilis,
and Crotalaria intermedia gave higher yields of green top growth
with the zinc sulphate. Of the plants responding to zinc sul-
phate, the increases in green top growth were smallest for the
5 pounds per acre rate of application, intermediate for the 15
pounds per acre rate, and largest for the 60 pounds per acre
rate. for all crops except the second cutting of Napier grass.
Sorghum and Crotalaria striata failed to respond to the zinc
sulphate applications.
In 1935, Napier grass produced substantially more top growth
on the zinc sulphate treated plots. The increase in top growth
on these plots was progressively higher with the higher rates
of application, though the greatest increment was obtained with
the 5 pounds per acre rate. Sorghum again failed to respond
to the application of zinc sulphate.
It appears from these results that a number of field crops
when grown on white bud land will respond with an increased
yield to the application of zinc sulphate to the soil. Such in-
creases may be expected despite the fact that physical symptoms
of malnutrition have not been detected. No experiments or
observations have been made on the response of these field crops
to the application of zinc sulphate to soils which do not produce
white bud of corn.
SUMMARY

1. White bud, a type of chlorosis, is a nutritional disorder of
corn frequently occurring in the fields of central, north and
northwest Florida. The chlorosis is prevalent particularly in
fields kept in culture annually. When white bud is severe, many
plants in the field die and the growth of those remaining is
stunted and unsatisfactory. The chlorosis develops in varying
degrees of intensity in different fields. Careful experimentation
has shown the development of white bud of corn may be wholly
prevented by:
(a) the application of zinc sulphate in relatively small quan-
tities in the row before planting;
(b) the application of animal manures to the soil;
It may be at least partially prevented by:
(c) the application of certain types of rough or crude organic
materials such as leafmold to the soil;





Florida Agricultural Experiment Station


(d) practicing "land-resting" or fallowing one or two years
to volunteer weeds and grasses which materially reduces the
severity of white bud.
2. In fields of Norfolk and Hernando medium fine sands in
which white bud of corn had developed severely for several
years, 12 pounds per acre of 89 percent zinc sulphate mixed
with a 5-5-5 fertilizer made from nitrate of soda, cottonseed
meal, superphosphate and muriate of potash, prevented the white
bud condition and gave greatly increased grain yields. Fifteen
pounds per acre of 89 percent zinc sulphate applied separately
but in conjunction with 0-4-4 and 7.5-4-4 fertilizer made from
urea, superphosphate and muriate of potash prevented the white
bud condition of corn, gave greatly increased grain yields and
increased the efficiency of the urea.
3. In tests on the rate of application, 10 to 20 pounds per
acre of 89 percent zinc sulphate applied in the row, separate
from but in conjunction with a complete fertilizer, proved the
most efficient rates.
4. Zinc sulphate when applied in the row before planting corn
increased the efficiency of side-dressing with nitrate of soda.
5. In seven field experiments, 20 pounds per acre of 89 per-
cent zinc sulphate were applied, mixed with 4-0-4 and 4-8-4
inorganic fertilizers made from nitrate of soda, superphosphate
and muriate of potash. The yields of corn in these experiments
show that there is a mutual interference of the response of the
corn plant to phosphate and zinc fertilization when superphos-
phate and zinc sulphate are mixed before application in the row.
The increase in corn yields was higher when zinc sulphate was
applied separately from the inorganic 4-8-4 mixture than when
it was mixed directly with the fertilizer before application in
the row. The mutual interference of superphosphate and zinc
sulphate was not observed when cottonseed meal was used as
a source of part of the nitrogen in 4-8-4 mixtures made from
nitrate of soda, cottonseed meal, superphosphate and muriate
of potash.
6. Peanut yields were increased in some instances when zinc
sulphate was mixed with inorganic 4-8-4 and 4-0-4 fertilizer
mixtures made from nitrate of soda, superphosphate and muriate
of potash. The increases in dry nut yields that may be attrib-
uted to zinc sulphate were neither as large nor as consistent as
those obtained with corn. No physical symptoms of malnutri-





Tl I s or Zinc Sulpho h I iou I- F; / ( /doCro


tion were observed on peanuts growing on soils producing white
bud of corn.
7. Oats grown on land which had produced white bud of corn
responded favorably with increased yields to the application of
zinc sullhate in or between the drill rows. No definite physical
symptoms of malnutrition were observed in the plots without
zinc sulphate but the oats with zinc sulphate matured approxi-
mately two weeks before those without zinc sulphate.
8. The yields of green top growth of velvet beans, cowpeas
and Pearl millet grown on land producing white bud corn were
increased by the application of zinc sulphate in the row before
planting. Plants growing in plots without zinc sulphate de-
veloped definite physical symptoms of malnutrition which have
been photographed and described. These symptoms were not
observed in plots receiving applications of zinc sulphate in the
row before planting.
9. Yields of green top growth of sugaicane, Napier grass,
Crotalaria spectabilis and Crotalaria intcrm,,edli grown on land
producing white bud corn were increased definitely by the ap-
plication of zinc sulphate in the row before planting. To date
no definite physical symptoms of malnutrition in these plants
have been observed when they are grown without zinc sulphate.

LITERATURE CITED
1. BARNETTE, R. M.. and .1. D. WARNER. A response .if "chlorotic" corn
plants to the application of zinc sulfate to the soil. Soil Sci. 39: 143-
159. 1935.
2. COOPER. H. 1'.. and W. I). MOoRE. Fertilizer uroblenms with truck crops.
S. C. Agr. Exp. Sta.. 46th Ann. Rept. 178-179l. 1933.
:1. FISHER. R. A. Statistical Methods for Research Workers. (liver and
Boyd. London. 193:.
4. JoNES, J. I'. Deficiency of magnesium the cause of' a chlorosis in corn.
Jour. Agr. Res. 39: 873-892. 1929.
5. MOWRY, HAROLD. Propagation, planting and fertilizing tests with tung
oil trees. Uni. of Fla. Agr. Exp. Sta. Ann. Rept. 91-195. 1933.
;. MOWRY, HAROLD, and A.. F. ('AM. A preliminary report on zinc sulphate
as a corrective for bronzing of tuni trees. Uni. of Fla. Agr. Exp. Sta.
Bul. 273. 1934.
7. PETTINGER. N. A., R. G. HENDERSON, and S. A. W'INGARDI. Some Inutri-
tional disorders in corn grown in sand cultures. Phytopath. 22: :i-.i1.
1932.
S. SKINNER. J. J., and R. W. RI PRECHT. Fertilizer e.:perinients with truck
crops. Uni. of FaI. Agr. F p. Sta. Bul. 218. 19:30.
i. WARNER, J. D. Corn fertilizer e\xeriments. Uni. ,of la. Agr. Exp.
Sta. Annual Renort. 4S. 19:2.






























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