• TABLE OF CONTENTS
HIDE
 Front Cover
 Credits
 Table of Contents
 Introduction and plan of exper...
 Experimental results of fertilizer...
 Rates of fertilizer and varying...
 Minor element studies with tobacco...
 Summary and conclusions
 Suggested practices
 Current fertilizer recommendat...






Group Title: Bulletin - University of Florida. Agricultural Experiment Station ; 512
Title: Fertilizer tests with flue-cured tobacco
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00027425/00001
 Material Information
Title: Fertilizer tests with flue-cured tobacco
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 27 p. : ill. ; 23 cm.
Language: English
Creator: Clark, Fred ( Fred A )
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1953
 Subjects
Subject: Tobacco -- Fertilizers -- Florida   ( lcsh )
Tobacco -- Field experiments -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: by Fred Clark.
General Note: Cover title.
 Record Information
Bibliographic ID: UF00027425
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aleph - 000926025
oclc - 18269533
notis - AEN6684

Table of Contents
    Front Cover
        Page 1
    Credits
        Page 2
        Page 3
    Table of Contents
        Page 4
    Introduction and plan of experiment
        Page 5
        Page 6
    Experimental results of fertilizer trials
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
        Page 21
    Rates of fertilizer and varying number of plants per acre
        Page 22
        Page 23
    Minor element studies with tobacco and acid, basic and neutral fertilizers
        Page 24
    Summary and conclusions
        Page 25
    Suggested practices
        Page 26
    Current fertilizer recommendations
        Page 27
Full Text


January 1953


UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATIONS
WILLARD M. FIFIELD, Director
GAINESVILLE, FLORIDA







Fertilizer Tests with Flue-Cured

Tobacco


By FRED CLARK


Fig. 1.-Tobacco fertilized with 1,000 pounds 0-8-6
3-8-6 (right).


(left) and 1,000 pounds


44~SIMWlNl


Bulletin 512









BOARD OF CONTROL

Frank M. Harris, Chairman, St. Petersburg
Hollis Rinehart, Miami
Eli H. Fink, Jacksonville
George J. White, Sr., Mount Dora
Mrs. Alfred I. duPont, Jacksonville
George W. English, Jr., Ft. Lauderdale
W. Glenn Miller, Monticello
W. F. Powers, Secretary, Tallahassee
EXECUTIVE STAFF
J. Hillis Miller, Ph.D., President 3
J. Wayne Reitz, Ph.D., Provost for Agr.3
Willard M. Fifield, M.S., Director
J. R. Beckenbach, Ph.D., Asso. Director
L. O. Gratz, Ph.D., Assistant Director
Rogers L. Bartley, B.S., Admin. Mgr.3
Geo. R. Freeman, B.S., Farm Superintendent

MAIN STATION, GAINESVILLE

AGRICULTURAL ECONOMICS
H. G. Hamilton, Ph.D., Agr. Economist 1 3
R. E. L. Greene, Ph.D., Agr. Economist 3
M. A. Brooker, Ph.D., Agr. Economist 3
Zach Savage, M.S.A., Associate
A. H. Spurlock, M.S.A., Associate
D. E. Alleger, M.S., Associate
D. L. Brooke, M.S.A., Associate
M. R. Godwin, Ph.D., Associate 3
W. K. McPherson, M.S., Economist "
Eric Thor, M.S., Asso. Agr. Economist :
J. L. Tennant, Ph.D., Agr. Economist
Cecil N. Smith, M.A., Asso. Agr. Economist
Levi A. Powell, Sr., M.S.A., Assistant
Orlando, Florida (Cooperative USDA)
G. Norman Rose, B.S., Asso. Agri. Economist
J. C. Townsend, Jr., B.S.A., Agricultural
Statistician 2
J. B. Owens, B.S.A., Agr. Statistician 2
J. K. Lankford, B.S., Agr. Statistician

AGRICULTURAL ENGINEERING
Frazier Rogers, M.S.A., Agr. Engineer 1 3
J. M. Myers, B.S., Asso. Agr. Engineer
J. S. Norton, M.S., Asst. Agr. Eng.

AGRONOMY
Fred H. Hull, Ph.D., Agronomist 1 2
G. B. Killinger, Ph.D., Agronomist
H. C. Harris, Ph.D., Agronomist
R. W. Bledsoe, Ph.D., Agronomist
W. A. Carver, Ph.D., Associate
Darrel D. Morey, Ph.D., Associate 2
Fred A. Clark, M.S., Assistant2
Myron G. Grennell, B.S.A.E., Assistant
E. S. Horner, Ph.D., Assistant
A. T. Wallace, Ph.D., Assistant 3
D. E. McCloud, Ph.D., Assistant 3
G. C. Nutter, Ph.D., Asst. Agronomist

ANIMAL HUSBANDRY AND NUTRITION
T. J. Cunha, Ph.D., An. Husb. 3
G. K. Davis, Ph.D., Animal Nutritionist 3
S. John Folks, Jr., M.S.A., Asst. An. Husb. 3
A. M. Pearson, Ph.D., Asso. An. Husb.3
John P. Feaster, Ph.D., Asst. An. Natri.
H. D. Wallace, Ph.D., Asst. An. Husb.3
M. Koger, Ph.D., An. Husbandman 8
E. F. Johnston, M.S., Asst. An. Hush. 3
J. F. Hentges, Jr., Ph.D., Asst. An. Husb. 3
L. R. Arrington, Ph.D., Asst. Biochemist

DAIRY SCIENCE
E. L. Fouts, Ph.D., Dairy Tech.1 3
R. B. Becker, Ph.D., Dairy Hush.3
S. P. Marshall, Ph.D., Asso. Dairy Husb.'
W. A. Krienke, M.S., Asso. Dairy Tech."
P. T. Dix Arnold, M.S.A., Asst. Dairy Husb. 3
Leon Mull, Ph.D., Asso. Dairy Tech. 3
H. H. Wilkowske, Ph.D., Asst. Dairy Tech. 3
James M. Wing, Ph.D., Asst. Dairy Hush.


EDITORIAL
J. Francis Cooper, M.S.A., Editor
Clyde Beale, A.B.J., Associate Editor
L. Odell Griffith, B.A.J., Asst. Editor 3
J. N. Joiner, B.S.A., Assistant Editor 3
William G. Mitchell, A.B.J., Assistant Editor

ENTOMOLOGY
A. N. Tissot, Ph.D., Entomologist
L. C. Kuitert, Ph.D., Associate
H. E. Bratley, M.S.A., Assistant
F. A. Robinson, M.S., Asst. Apiculturist
R. E. Waites, Ph.D., Asst. Entomologist

HOME ECONOMICS
Ouida D. Abbott, Ph.D., Home Econ.1
R. B. French. Ph.D., Biochemist

HORTICULTURE
G. H. Blackmon, M.S.A., Horticulturist
F. S. Jamison, Ph.D., Horticulturist 3
Albert P. Lorz, Ph.D., Horticulturist
R. K. Showalter, M.S., Asso. Hort.
R. A. Dennison, Ph.D., Asso. Hort.
R. H. Sharpe, M.S., Asso. Horticulturist
V. F. Nettles, Ph.D., Asso. Horticulturist
F. S. Lagasse, Ph.D., Horticulturist 2
R. D. Dickey, M.S.A., Asso. Hort.
L. H. Halsey, M.S.A., Asst. Hort.
C. B. Hall, Ph.D., Asst. Horticulturist
Austin Griffiths, Jr., B.S., Asst. Hort.
S. E. McFadden, Jr., Ph.D., Asst. Hort.
C. H. VanMiddelem, Ph.D., Asst. Biochemist
Buford D. Thompson, M.S.A., Asst. Hort.
James Montelaro, Ph.D., Asst. Horticulturist
M. W. Hoover, M.S.A., Asst. Hort.

LIBRARY
Ida Keeling Cresap, Librarian

PLANT PATHOLOGY
W. B. Tisdale, Ph.D., Plant Pathologist 3
Phares Decker, Ph.D., Plant Pathologist
Erdman West, M.S., Mycologist and
Botanist 3
Robert W. Earhart, Ph.D., Plant Path.2
Howard N. Miller, Ph.D., Asso. Plant Path.
Lillian E. Arnold, M.S., Asst. Botanist
C. W. Anderson, Ph.D., Asst. Plant Path.
POULTRY HUSBANDRY
N. R. Mehrhof, M.Agr., Poultry Husb.' 3
J. C. Driggers, Ph.D., Asso. Poultry Husb.
SOILS
F. B. Smith Ph.D., Microbiologist'
Gaylord M. Volk, Ph.D., Soils Chemist
J. R. Neller, Ph.D., Soils Chemist
Nathan Gammon, Jr., Ph.D., Soils Chemist
Ralph G. Leighty, B.S., Asst. Soil Surveyor 2
G. D. Thornton, Ph.D., Asso. Microbiologist s
Charles F. Eno, Ph.D., Asst. Soils Micro-
biologist
H. W. Winsor, B.S.A., Assistant Chemist
R. E. Caldwell, M.S.A., Asst. Chemists3
V. W. Carlisle, B.S., Asst. Soil Surveyor
J. H. Walker, M.S.A., Asst. Soil Surveyor
S. N. Edson, M. S., Asst. Soil Surveyor s
William K. Robertson, Ph.D., Asst. Chemist
O. E. Cruz, B.S.A., Asst. Soil Surveyor
W. G. Blue, Ph.D., Asst. Biochemist
J. G. A. Fiskel, Ph.D., Asst. Biochemist3 -
L. C. Hammond, Ph.D., Asst. Soil Physicist
H. L. Breland, Ph.D., Asst. Soils Chem.

VETERINARY SCIENCE
D. A. Sanders, D.V.M.. Veterinarian 3
M. W. Emmel, IY.V.M., Veterinarian
C. F. Simpson, D.V.M., Asso. Veterinarian
L. E. Swanson, D.V.M., Parasitologist
Glenn Van Ness, D.V.M., Asso. Poultry
Pathologist 3
W. R. Dennis, D.V.M., Asst. Parasitologist
E. W. Swarthout, D.V.M., Asso. Poultry
Pathologist (Dade City)









BRANCH STATIONS

NORTH FLORIDA STATION, QUINCY
W. C. Rhoades, Jr., M.S., Entomologist in
Charge
R. R. Kincaid, Ph.D., Plant Pathologist
L. G. Thompson, Jr., Ph.D., Soils Chemist
W. H. Chapman, M.S., Asso. Agronomist
Frank S. Baker, Jr., B.S., Asst. An. Hush.
T. E. Webb, B.S.A., Asst. Agronomist
Frank E. Guthrie, Ph.D., Asst. Entomologist
Mobile Unit, Monticello
R. W. Wallace, B.S., Associate Agronomist
Mobile Unit, Marianna
R. W. Lipscomb, M.S., Associate Agronomist
Mobile Unit, Pensacola
R. L. Smith, M.S., Associate Agronomist
Mobile Unit, Chipley
J. B. White, B.S.A., Associate Agronomist

CITRUS STATION, LAKE ALFRED
A. F. Camp, Ph.D., Vice-Director in Charge
W. L. Thompson, B.S., Entomologist
R. F. Suit, Ph.D., Plant Pathologist
E. P. Ducharme, Ph.D., Asso. Plant Path.
C. R. Stearns, Jr., B.S.A., Asso. Chemist
J. W. Sites, Ph.D., Horticulturist
H. 0. Sterling, B.S., Asst. Horticulturist
H. J. Reitz, Ph.D., Horticulturist
Francine Fisher, M.S., Asst. Plant Path.
I. W. Wander, Ph.D., Soils Chemist
J. W Kesterson, M.S., Asso. Chemist
R. Hendrickson, B.S., Asst. Chemist
Ivan Stewart, Ph.D., Asst. Biochemist
D. S. Prosser, Jr., B.S., Asst. Horticulturist
R. W. Olsen, B.S., Biochemist
F. W. Wenzel, Jr., Ph.D., Chemist
Alvin H. Rouse, M.S., Asso. Chemist
H. W. Ford, Ph.D., Asst. Horticulturist
L. C. Knorr, Ph.D., Asso. Histologist 4
R. M. Pratt, Ph.D., Asso. Ent.-Pathologist
J. W. Davis, B.S.A., Asst. in Ent.-Path.
W. A. Simanton, Ph.D., Entomologist
E. J. Deszyck, Ph.D., Asso. Horticulturist
C. ID. Leonard, Ph.D., Asso. Horticulturist
W. T. Long, M.S., Asst. Horticulturist
M. H. Muma, Ph.D., Asso. Entomologist
F. J. Reynolds, Ph.D., Asso. Hort.
W. F. Spencer, Ph.D., Asst. Chem.
I. H. Holtsberg, B.S.A., Asst. Ento.-Path.
K. G. Townsend, B.S.A., Asst. Ento.-Path.
J. B. Weeks, B.S., Asst. Ento.-Path.
R. B. Johnson, Ph.D., Asst. Entomologist
W. F. Newhall, Ph.D., Asst. Biochem.
W. F. Grierson-Jackson. Ph.D., Asst. Chem.
Roger Patrick, Ph.D., Bacteriologist
Marion F. Oberbacher, Ph.D., Asst. Plant
Physiologist
Evert J. Elvin, B.S., Asst. Horticulturist

EVERGLADES STATION, BELLE GLADE
W. T. Forsee, Jr., Ph.D., Chemist in Charge
R. V. Allison, Ph.D., Fiber Technologist
Thomas Bregger, Ph.D., Physiologist
J. W. Randolph, M.S., Agricultural Engr.
R. W. Kidder, M.S., Asso. Animal Hush.
C. C. Seale, Associate Agronomist
N. C. Hayslip, B.S.A., Asso. Entomologist
E. A. Wolf,, .., Asst. Horticulturist
W. H. Thames, M.S., Asst. Entomologist
W. N. Stoner, Ph.D., Asst. Plant Path.
W. G. Genung, B.S.A., Asst. Entomologist
Frank V. Stevenson, M.S., Asso. Plant Path.
Robert J. Allen, Ph.D., Asst. Agronomist
V. E. Green, Ph.D., Asst. Agronomist
J. F. Darby, Ph.D., Asst. Plant Path.
H. L. Chapman, Jr., M.S.A., Asst. An. Husb.
V. L. Guzman, Ph.D., Asst. Hort.
M. R. Bedsole, M.S.A., Asst. Chem.
J. C. Stephens. B.S., Drainage Engineer2
A. E. Kretschmer, Jr., Ph.D., Asst. Soils
Chem.


SUB-TROPICAL STATION, HOMESTEAD
Geo. D. Ruehle, Ph.D., Vice-Dir. in Charge
D. 0. Wolfenbarger, Ph.D., Entomologist
Francis B. Lincoln, Ph.D., Horticulturist
Robert A. Conover, Ph.D., Plant Path.
John L. Malcolm, Ph.D., Asso. Soils Chemist
R. W. Harkness, Ph.D., Asst. Chemist
R. Bruce Ledin, Ph.D., Asst. Hort.
J. C. Noonan, M.S., Asst. Hort.
M. H. Gallatin, B.S., Soil Conservationist2

WEST CENTRAL FLORIDA STATION,
BROOKSVILLE
Marian W. Hazen, M.S., Animal Husband-
man in Charge 2

RANGE CATTLE STATION, ONA
W. G. Kirk, Ph.D., Vice-Director in Charge
E. M. Hodges, Ph.D., Agronomist
D. W. Jones, M.S., Asst. Soil Technologist

CENTRAL FLORIDA STATION, SANFORD
R. W. Ruprecht, Ph.D., Vice-Dir. in Charge
J. W. Wilson, Sc.D., Entomologist
P. J. Westgate, Ph.D., Asso. Hort.
Ben. F. Whitner, Jr., B.S.A., Asst. Hort.
Geo. Swank, Jr., Ph.D., Asst. Plant Path.

WEST FLORIDA STATION, JAY
C. E. Hutton, Ph.D., Vice-Director in Charge
H. W. Lundy, B.S.A., Associate Agronomist
W. R. Langford, Ph.D., Asst. Agronomist

SUWANNEE VALLEY STATION,
LIVE OAK
G. E. Ritchey, M.S., Agronomist in Charge

GULF COAST STATION, BRADENTON
E. L. Spencer, Ph.D., Soils Chemist in Charge
E. G. Kelsheimer, Ph.D., Entomologist
David G. A. Kelbert, Asso. Horticulturist
Robert O. Magie, Ph.D., Plant Pathologist
J. M. Walter, Ph.D., Plant Pathologist
Donald S. Burgis, M.S.A., Asst. Hort.
C. M. Geraldson, Ph.D., Asst. Horticulturist
Amegda Jack, M.S., Asst. Soils Chemist


FIELD LABORATORIES

Watermelon, Grape, Pasture-Leesburg
J. M. Crall, Ph.D., Associate Plant Path-
ologist Acting in Charge
C. C. Helms, Jr., B.S., Asst. Agronomist
L. H. Stover, Assistant in Horticulture
Strawberry-Plant City
A. N. Brooks, Ph.D., Plant Pathologist
Vegetables-Hastings
A. H. Eddins, Ph.D., Plant Path. in Charge
E. N. McCubbin, Ph.D., Horticulturist
T. M. Dobrovsky, Ph.D., Asst. Entomologist
Pecans-Monticello
A. M. Phillips, B.S., Asso. Entomologist 2
John R. Large, M.S., Asso. Plant Path.
Frost Forecasting-Lakeland
Warren O. Johnson, B.S., Meterologist in
Chg.

1 Head of Department
2 In cooperation with U. S.
3 Cooperative, other divisions, U. of F.
4 On leave











CONTENTS


Page
INTRODUCTION ............--.....-. ..-..----- ------------ 5

PLAN OF EXPERIMENTS ..........-----.......--- ...------------------------- 5

EXPERIMENTAL RESULTS OF FERTILIZER TRIALS .........................---....----....-------- 7

Nitrogen-- Rates and Sources ...................................... 7

Phosphorus .............................. --........... .--------- 12

Potassium ................................................................ 12

Calcium ........................................... .... ..... ---- .... 17

M agnesium ................................................ .............. 17

Sulfur .................-- .........-.- ..- -.................. -----.- 18

Chlorine ....................... ................. ...... ------- -- 19

B oron ................................................ ---.... ..... 20

RATES OF FERTILIZER AND VARYING NUMBER OF PLANTS PER ACRE ............ 22

MINOR ELEMENT STUDIES WITH TOBACCO ............................. ....--- ....... 24

ACID, BASIC AND NEUTRAL FERTILIZERS ......................... .......................-----24

SUMMARY AND CONCLUSIONS ................--........................ .................. 25

SUGGESTED PRACTICES ......................................... --------.. 26

CURRENT FERTILIZER RECOMMENDATIONS ............--...........--.-----......... 27








Fertilizer Tests with Flue-Cured Tobacco
By FRED CLARK

INTRODUCTION
Flue-cured tobacco is one of the heavily fertilized crops grown
in the general farming area of Florida. Tobacco fertilizers re-
quire special attention, because good quality leaf depends upon
the presence of certain nutrients in the proper proportions. An
unbalanced nutrient level may result in undesirable color, poor
elasticity and excessive thickness of the cured leaf.
Tobacco plants should be grown with a balanced nutrient en-
vironment to produce maximum yield and quality. The nutrient
level may be materially affected by soil type and weather condi-
tions at time of growth.
This bulletin presents results of fertilizer tests with flue-cured
tobacco.
PLAN OF EXPERIMENTS
Data reported here are from experiments conducted during
the 1939-1944 seasons on Norfolk fine sand with a pH of approxi-
mately 5.7, near Gainesville, Florida.' The experimental area
was cleared of scattered pine, scrub' oak and wiregrass prior to
these tests.
Triplicate four-row 1/40-acre plots were laid out in a random-
ized block design. Tobacco was grown in a three-year rotation
of weeds, oats and cattail millet, with tobacco planted on the area
every third year. One year of weeds always preceded the crop
of tobacco.
Fertilization.-The following series of fertilizer tests were
conducted: rates and sources of nitrogen; rates of phosphorus,
potassium, calcium, magnesium, sulfur, chlorine and boron;
rates of fertilizer and varying number of plants per acre; minor
elements; and a comparison of acid, basic and neutral mixed
fertilizers. The base treatment around which variations were
made was 30 pounds of nitrogen (N), 80 pounds phosphorus
(P20), 60 pounds potassium (K20), 80 pounds calcium (CaO),
89 pounds sulfur (SO3), 20 pounds chlorine (Cl2) and 0.5 pounds
of boron per acre. Each nutrient was increased, decreased, or
withheld by using materials listed in Table 1. All fertilizers
were applied in bands to the side of the plants.
1These investigations were initiated under the direction of W. E. Stokes,
head of the Department of Agronomy, who died July 19, 1948.












TABLE 1.-COMPOSITION OF FERTILIZER MATERIALS IN PERCENT.
N P20 K2O I CaO MgO Cl SOs B

Ammonium sulfate ........................ 20.0 ...... ...... ...... ...... 57.5 --
Calcium nitrate ...................................... 15.5 ...... ...... 28.0 -- .. --
Cottonseed meal ...................................... 7.0 3.0 2.0 ...... 1.0 ...... ......----
Di-ammonium phosphate ..--..............-... 21.1 53.17 i ... .. ......... -....-
D olom ite ................................................. ...... ...... ...... 29.6 17.6 ..... .
Epsom salts ..................-...................... ...... I ...... ..... ...... 16.0 ...... 32.5 ...
Ground fish .............................................. 9.0 7.0 ...... .... ...... .... 2.8 ...
Gypsum ...................................................... ............ ...... 30.5 43.5 ......
M uriate of potash .................................. ...... I ...... 50.0 ...... ...... 46.5..--
Mono-ammonium phosphate ................ 10.6 61.0 I .... .. ---
M agnesium chloride .............................. ...... ...... ...... 19.8 34.9 ...... .....
Mono-calcium phosphate ...................... ...... 56.7 ...... 22.1 ...
Mono-potassium phosphate .................. ...... 52.2 30.3 .........
Nitrate of potash ................................... 12.3 ...... 44.0
Nitrate of soda (Chil.) ........................ 15.9 ..... 0.4 .3 T .50 .20 .028
Potassium carbonate ............................ ............ 61.0 ............--
Potassium carbonate (C. P.) .... ...... ...... 67.0 ......
Superphosphate ..................................... ...... 20.0 ...... 25.0 ...... ......29... .0
Sulfate potash ....................................... ...... ...... 48.0 ............ ...... 42.0 ..
Sulfate of potash magnesia ............. ...... ...... 27.0 ..... 9.0 ...... 45.0 -.-
U rea ........................................ .............. 46.0 ...... ...... I -
M agnesium nitrate ................................ 10.9 I ........ ...... 15.7 ...
Dicalcium phosphate (pptd. bone) .... ..... 40.9 ...... 32.5 ............
Borax --..................------- .................................... ...... ...... ...... ...... 11.34






Fertilizer Tests with Flue-Cured Tobacco


Field Planting Procedure.-The land was prepared in late
winter or early spring by plowing and disking. Sufficient time
was allowed for the decomposition of crop residues before trans-
planting. Transplanting was generally begun the last week in
March. A given test was transplanted in one day and all tests
within not more than three days. Plants were carefully set with
a hand transplanter. The amount of replanting was negligible.
The variety Bonanza was used in all tests. The tobacco was
primed at weekly intervals and was all cured in the same barn,
with kerosene oil used as the fuel.
Methods of Evaluating Treatments.-The tobacco harvested
from each plot was graded and weighed separately and samples
were chosen at random from the various farm grades. These
samples were later graded by official United States Department
of Agriculture tobacco graders. The acre value for each treat-
ment was calculated by the use of the current season's average
price for the various grades on Florida tobacco markets, as re-
ported by the Tobacco Marketing and Grading Service.

EXPERIMENTAL RESULTS
NITROGEN-RATES AND SOURCES
Nitrogen is closely associated with many of the constituents
of quality. In these tests it stimulated growth more than any
other element tested (see Figures 1 and 2). Over-fertilization
with nitrogen will result in the production of a tobacco undesir-
ably high in nicotine, low in sugar, off in color and poor in quality.
Results of single sources and combinations of sources of nitro-
gen are given in Tables 2 and 3. There were no significant
differences in yield and quality from nitrate of soda, sulfate of
ammonia and urea as single sources. However, cottonseed meal
produced significantly lower yields than the mineral sources.
The highest yield resulted from the use of a fertilizer having
one-third nitrate of soda, one-third sulfate of ammonia and one-
third urea, followed closely by a formula having one-half nitrate
of soda and one-half sulfate of ammonia; and one carrying one-
third sulfate of ammonia, one-third urea and one-third cotton-
seed meal.
Quality was uniformly good for all of the high-yielding treat-
ments. When none of the applied nitrogen was of the nitrate
form a characteristic typical rolled margin of the leaf developed
(see Figure 3). This condition is somewhat similar to, but should






Florida Agricultural Experiment Stations


not be confused with, the effect of excess chlorine (see Figures
6 and 7).


Fig. 2.-Leaves from tobacco fertilized with different levels of nitrogen.
Left to right-0, 30 and 40 pounds nitrogen per acre. Note darker green
color of leaf produced by 40 pounds of nitrogen.

Tobacco fertilizers generally have from 20 to 40% organic
nitrogen. The organic nitrogen is thought to keep tobacco from
ripening too rapidly by maintaining a more uniform nitrogen
level in case of excessive leaching of the more soluble forms. The
all-mineral nitrogen was as good as the organic in these tests.
In several tobacco areas in Florida, from 100 to 200 pounds of
cottonseed meal is applied, in addition to the regular fertilizer
before transplanting. This adds as much as 10 to 12 pounds of
nitrogen, 6 pounds of phosphoric acid and 4 pounds of potash
to the regular application. With this practice approximately
two-thirds of the nitrogen is from organic sources.
Thirty pounds of nitrogen per acre from manure as the sole
source of nitrogen (Table 4) was not satisfactory. However, in
a later test a 3-8-6 fertilizer was added to a drill row application
of manure containing 30 pounds nitrogen equivalent per acre,
which increased the yield more than 200 pounds per acre and
gave excellent quality.


_ii 1









TABLE 2.-EFFECT OF VARIOUS RATES OF NITROGEN ON YIELD AND PRICE OF TOBACCO.


Nitrogen*


Lbs./A

0-8-6 .......................................

20-8-6 ........................-- ...
2 5 -8 -6 --------------------------------------
250-8-6 ..................................


35-8-6 .....................................

40-8-6 ....................................

45-8-6 ..................................

'(1 LS.D. (.05)- 76 pounds
(.01)-101 pounds


Yield per Acre Pounds

1939-41 1939-44

Lbs./A


553(1)

921

972

1093

1030

981

1061


813'"

965

942

915

932


Selling Price per

1939-41


$15.18

16.93

17.49

17.47

16.50

15.29

16.49


100 Pounds

1939-44







$25.83

27.42

26.65

26.12

26.48


Gross Value per Acre


1939-41



$ 84

156

170

191

170

150

175


1939-44







$210

255

251

239

260


"' The yearly yields for the fertilizers differed greatly
differed only slightly.


but the yield ranks of fertilizer treatment for the various years


In addition to the variable each treatment included 80 lbs. POs; 60 lbs. KsO; 80 lbs. CaO; 20 lbs. MgO; 89 Ibs. SO.; 20 lbs. CI; 0.5 lb. boron per
acre.
** Base treatment.








TABLE 3.-EFFECT OF VARIOUS SOURCES OF NITROGEN ON YIELD AND PRICE
OF TOBACCO (1939-1943).

Pounds of Nitrogen I
Fertilizer I Sul- I Pounds Price I Gross
Analysis INitrate I phate I Cotton-I per per IValue
1000 Lbs. I of ] of Urea seed Acre 100 I er
per Acre Soda Am- I I Meal I Pounds Acre
___ I monia I__
3-8-6 ........ 30 968 $23.76 $230
3-8-6 ........ 30 994 23.94 238
3-8-6 ........ 30 973 23.53 229
3-8-6 ........ 30 883 23.22 205
3-8-6 ........ 15 15 1028 23.93 246
3-8-6 ........ 15 15 1004 23.90 240
3-8-6 ........ 15 15 962 24.74 238
3-8-6 ........ 15 15 926 23.43 217
3-8-6 ........ 15 15 988 24.04 238
3-8-6 ........ 15 15 988 23.99 237
3-8-6 ........ 10 10 10 1049 24.69 259
3-8-6 ........ 10 10 10 932 24.57 229
3-8-6 ........ 10 10 10 962 24.84 239
3-8-6 ........ 10 10 10 1026 24.17 248
3-8-6 ........ 7.5 7.5 7.5 7.5 946 24.52 232
L. S. D. (.05) 86
SAll treatments supplied, 30 pounds nitrogen, 80 pounds P202, 60 pounds KO0, 80 lbs.
CaO, 20 lbs. MgO, 89 lbs. SOs, 20 lbs. Cl, and 0.5 Ib. boron per acre respectively when used
at the rate of 1,000 pounds per acre.

Fig. 3.-Response of tobacco to nitrate and ammoniacal forms of nitro-
gen. Left, 15 pounds N from nitrate of soda and 15 pounds from cotton-
seed meal; right, 15 pounds N from sulfate of ammonia and 15 pounds
from cottonseed meal. Note uprolled leaves with margins split. This
condition was aggravated by cold weather.










.. -.
.- '

zjrT~If
















TABLE 4.-EFFECT OF MANURE AS A SOURCE OF NITROGEN ON THE YIELD AND PRICE OF TOBACCO.

I Yield per Acre Pounds Selling Price per 100 Lbs. I Gross Value per Acre
Fertilizer Analysis I I
1000 Pounds per Acre 1939-41 1941-43 1939-41 i 1941-43 I 1939-41 I 1941-43
______ ___I


0-8-6 .......... .......................

3-8-6 ......... ...............

0-8-6 + Manure* ..............

3-8-6 + Manure* ...........


498

829


1057


14.93

17.09

14.96


29.31

31.84


32.54


146

264


344


* Manure was applied at the rate of 30 pounds N. per acre.






Florida Agricultural Experiment Stations


PHOSPHORUS
Phosphorus deficiency is not as evident on tobacco grown in
Florida soils as in other tobacco-producing areas. Results with
different rates of phosphorus are given in Table 5. Yield and
quality of tobacco were improved by phosphorus up to the 80-
pound rate. It is believed that the early maturity caused by the
higher rates was responsible for the slightly lower yields.
Quality for all rates was fairly uniform. High phosphorus fertili-
zation hastened ripening of leaves and also flowering of plants
(see Figure 4 and Table 6). Low phosphorus prolongs the grow-
ing period and keeps the leaves darker green in color than those
grown with medium to high phosphorus during the entire grow-
ing period.
TABLE 5.-EFFECT OF VARIOUS RATES OF PHOSPHORUS ON YIELD AND PRICE
OF TOBACCO (1939-1944).
Phosphorus (P205)* Yield Selling Price I Gross Value
Applied per p er Acre, I per 100 [ per
Acre Pounds I Pounds Pounds I Acre

5 899 $26.47 $238
42 950 26.63 253
80** 995 27.74 276
117 947 26.82 254
155 954 27.46 262
192 970 27.84 270

L. S. D. (.05) 38 pounds
In addition to the variable phosphorus each treatment received 30 lbs. N., 60 lbs. K5O,
80 Ibs. CaO, 20 lbs. MgO, 89 lbs. SOs, 20 lbs. Cl, and 0.5 lbs. boron per acre.
** Base treatment.
POTASSIUM
Potassium requirements for flue-cured tobacco are high and on
light sandy soils the need is critical. However, a low level of
potassium does not retard growth as much as does a low level
of nitrogen. On the other hand, a relatively high potassium con-
tent in the cured tobacco leaf is desirable from the standpoint
of smoking quality.
Most of Florida's flue-cured tobacco soils are deficient in potas-
sium, requiring the use of fairly heavy rates of potassium for
good tobacco. When the potash level in the soils is low the
tobacco plant stops vegetative growth early, the leaves become
rough and crinkled, and reddish brown spots appear on the







Fertilizer Tests with Flue-Cured Tobacco


leaves (see Figure 5). Tobacco which has had adequate potas-
sium fertilizer will withstand drought better and will make better
recovery when moisture is available than will potash starved
plants.


Fig. 4.-Effect of rate of phosphorus on flowering. Left, fertilized
with 42 pounds phosphoric acid per acre; right, 192 pounds per acre. Note
earlier flowering.






Florida Agricultural Experiment Stations


Fig. 5.-Tobacco growth as influenced by potash fertilization. Left,
110 pounds potash per acre-leaves smooth; right, 10 pounds potash per
acre-leaves rough, with mottled (later necrotic) tips.


bco; NJ







Fertilizer Tests with Flue-Cured Tobacco


TABLE 6.-EFFECT OF


VARIOUS RATES OF PHOSPHORUS
TOBACCO (1940-1941).


ON FLOWERING OF


Average
Rates of Phosphorus Average Number of Plants Topped
(P20s) per Acre Topped in 3 Plots* for
(Pounds) 5/31/40 6/13/41 1940-41

5 72 31 52
42 84 87 85

80 95 82 88
117 101 101 101
160 102 107 105
192 96 96 I 96

132 plants per plot.


Table 7 reveals yield and quality as affected by the various
rates of potash. Tests show that 110- and 160-pound rates of
potash increased yields significantly over the 60-pound rate.


TABLE 7.-EFFECT OF VARIOUS RATES OF POTASH ON THE YIELD AND PRICE
OF TOBACCO (1939-1944).

Potash (K20)* I Yield I Price Gross
Applied per I per Acre, I per 100 Value
Acre Pounds I Pounds i Pounds per Acre

60** 897 $27.31 $245
110 969 27.66 268
160 1006 27.04 272
210 954 28.09 268

L. S. D. (.05) 74 pounds


In addition to the variable each treatment supplied 30 lbs. N, 80
CaO, 20 lbs. MgO, 89 lbs. SOs, 20 Ibs. Cl, and 0.5 lbs. boron per acre.
** Base treatment.


lbs. P205, 80 lbs.


Tests (Table 8) have shown that flowering is retarded by
higher levels of potassium, which is the opposite of results ob-
tained with high phosphorus. The longer vegetative growth
permitted the leaves to ripen more normally and they had a
smoother appearance than was the case otherwise.







Florida Agricultural Experiment Stations


TABLE 8.-EFFECT OF VARIOUS RATES OF POTASH AND SULFUR ON
FLOWERING OF TOBACCO (1940-1941).
I Average
Treatment in Pounds IAverage Number of Plants Topped for
per Acre Topped in 3 Plots* 1940-41
Potash I Sulfur (SO') I 5/13/40 6/13/41


* 132 plants per pot.


TABLE 9.-EFFECT OF VARIOUS RATES OF POTASH AND SULFUR ON THE
YIELD AND PRICE OF TOBACCO (1940-1941).
I I Gross
Treatment in Pounds I Yield Price Value
per Acre I per Acre per 100 per Acre
Potash I Sulfur (SO3) I Pounds Pounds (Dollars)

10 89 720 $15.83 $114
60 89** 957 20.27 194
110 89 1,049 20.97 220
160 89 1,036 20.46 212
210 89 963 19.93 192
260 89 943 20.14 190
260 263 1,106 21.43 237
310 89 1,004 20.71 208
310 307 1,178 20.80 1 245

L. S. D. (.05) = 122 pounds

In addition to the variable each treatment supplied 30 lbs. Nitrogen, 80 lbs. PZOs, 80
lbs. CaO, 20 lbs. MgO, 89 lbs. SOs, 20 Ibs. Cl, and 0.5 lbs. boron per acre.
** Base treatment.






Fertilizer Tests with Flue-Cured Tobacco


Effects of potassium and sulfur rates on growth of tobacco are
given in Table 9. There was a significant increase from incre-
ments of potash up to 110 pounds per acre, where sulfur was ap-
plied at 89 pounds per acre. Further significant increases were
obtained when sulfur was applied at the same high rate as potas-
sium. The extremely high rates of potash and sulfur are not
considered practical.
To determine whether additional potassium would be beneficial
when used with higher rates of nitrogen than the 30 pounds in
the base treatment, additional tests were made (Table 10).
Among the combinations tested, 40 pounds of nitrogen and 110
pounds of potash gave highest yields.

TABLE 10.-EFFECT OF VARIOUS RATES OF NITROGEN AND POTASH ON
YIELD* AND PRICE OF TOBACCO (1942-1944).
I Yield per I Selling Price I Gross Value
Per Acre Pounds** [ Acre I per 100 Per
Nitrogen IPotash Pounds I Pounds Acre

30 60 838 $37.95 $318
40 60 843 38.86 328
40 110 946 38.58 365
45 60 905 37.90 343
45 160 916 37.66 345

The yield differed greatly for years but the differences due to treatment x year inter-
action and average yield of treatment were not significant.-
** In addition to the nitrogen and potash indicated, each treatment supplied 80 lbs. P2Os,
80 lbs. CaO, 20 lbs. MgO, 89 lbs. SO3, 20 lbs. Cl, and 0.5 lbs. boron per acre.

CALCIUM
Calcium, as lime, is generally used to control soil acidity.
Calcium is also a plant nutrient, and may affect microbial de-
velopment in the soil. Results of the calcium test are given in
Table 11. None of the tested rates produced significant differ-
ences in yield and quality. The 80-pound rate used in the base
treatment appeared to be adequate.

MAGNESIUM
Magnesium is essential for chlorophyll formation. The lack
of this element causes a chlorosis which has been corrected by
magnesium fertilization. This chlorosis is called sand drown in
tobacco, and shows as a whitish mottling between the leaf veins.
Results with different rates of magnesium are given in Table 12.







Florida Agricultural Experiment Stations


No magnesium deficiency was observed in any tests and there
were no significant differences-among treatments.

TABLE 11.-EFFECT OF VARIOUS RATES ON CALCIUM YIELD* AND PRICE
OF TOBACCO (1939-1944).
Calcium (CaO)** Yield per ISelling Price Gross Value
Applied per Acre per 100 per
Acre-Pounds Pounds Pounds Acre

0 926 $26.45 $245
40 926 26.89 249
80- 967 27.30 264
120 924 27.06 250

The yearly yields differed significantly but the treatment differences were not signifi-
cant.
** In addition to the variable, each treatment received 30 Ibs. N, 80 lbs. P-Os, 60 lbs.
K2O, 20 lbs. MgO, 89 lbs. SOa, 20 lbs. Cl, and 0.5 lbs. boron per acre.
t Base treatment.


TABLE 12.-EFFECT OF VARIOUS RATES OF MAGNESIUM
PRICE OF TOBACCO (1939-1944).


ON YIELD* AND


Magnesium I
(MgO)** I Yield per I Selling Price IGross Value
Applied per I Acre per 100 per
Acre-Pounds I Pounds I Pounds Acre

5 929 $27.23 $253
20t 939 27.26 256
35 1004 26.69 268
50 966 27.23 263

The yields differed significantly for different years, but the treatment differences were
not significant.
** In addition to the variable each treatment received 30 lbs. N, 80 lbs. PsOs, 60 lbs.
KsO, 80 lbs. CaO, 89 lbs. SOs, 20 lbs. Cl, and 0.5 lbs. boron per acre.
t Base treatment.

SULFUR
Although sulfur fertilization has received widespread atten-
tion by many workers, it is generally accepted that sufficient
sulfur for maximum growth is supplied by most regular ferti-
lizers which carry considerable sulfate materials.
Results with different rates of sulfur (SOs) are given in Table
13. Uniform yields and quality were obtained from all rates.
Table 8 shows that high rates of sulfur slightly hastened flower-
ing of plants.







Fertilizer Tests with Flue-Cured Tobacco


TABLE 13.-EFFECT OF VARIOUS RATES OF SULFUR ON YIELD* AND PRICE
OF TOBACCO (1939-1944).


Sulfur (SOs)** I Yield per I Selling Price
Applied per Acre- per 100
Acre-Pounds Pounds Pounds

9 919 $26.55
49 921 26.06
89t 918 27.56

129 922 26.68
169 951 27.55


I Gross
Value
per Acre

$244
240
253

246
262


* The annual yields differed significantly


but the treatment differences were not signifi-


cant.
** In addition to the variable, each treatment received 30 lbs. N, 80 lbs. P2Os, 60 lbs.
K.O, 80 lbs. CaO, 20 Ibs. MgO, 20 lbs. Cl and 0.5 lbs. boron per acre.
SBase treatment.

CHLORINE

Chlorine is not considered an essential element for tobacco,
but small amounts seem to be beneficial. Data on chlorine re-
sponse are given in Table 14. There were significant increases
in yield from 20- and 40-pound rates of chlorine over the no-
chlorine treatment. Tobacco fertilized with 20 pounds of chlorine
produced normal leaves. However, tobacco fertilized with 40
pounds produced a thick, curled, glossy green leaf, as shown in
Figures 6 and 7. During the latter stages of growth, yellow
blotches appeared on the leaves. Their burning qualities were
impaired, they were too hygroscopic and they darkened during
handling.


TABLE 14.-EFFECT OF VARIOUS RATES OF CHLORINE ON YIELD AND PRICE
OF TOBACCO (1939-1944).
Chlorine (Cl)* Yield Selling Price I Gross
Applied per per Acre per 100 Value
Acre-Pounds -Pounds Pounds per Acre

0 851 $26.56 $226
20** 947 26.93 255
I
40 947 27.56 261

L. S. D. (.05) 66 pounds
In addition to the variable, each treatment received 30 lbs. N, 80 lbs. PsOs, 60 Ibs.
KO, 80 lbs. CaO, 20 lbs. MgO, 89 lbs. SOs, 20 lbs. Cl, and 0.5 lbs. boron per acre.
** Base treatment.







Florida Agricultural Experiment Stations


Fig. 6.-Effect of chlorine on leaf development. Tobacco fertilized with
40 pounds chlorine per acre shows uprolled leaf margin, dark green color
and bending down sharply at leaf center.


'3


Fig. 7.-Close-up view of leaves from tobacco fertilized with two rates
of chlorine. Left, 20 pounds, and right, 40 pounds, of chlorine per acre.

BORON
Boron is very toxic when used in excessive amounts and was
included in both rate and minor element tests to determine plant
response to this element. Results are given in Table 15.







Fertilizer Tests with Flue-Cured Tobacco


TABLE 15.-EFFECT OF VARIOUS RATES OF BORON ON YIELD AND PRICE OF
TOBACCO (1939-1944).
Boron (B)* Yield I Selling Price I Gross Value
Applied per I per Acre I per 100 I per
Acre-Pounds I -Pounds Pounds I Acre

0 931 $26.64 $248
.5** 939 27.37 I 257
3.0 822 24.70 203

L. S. D. (.05) = 64 pounds
In addition to the variable, each treatment received 30 lbs. N, 80 lbs. P.Os, 60 lbs.
K.O, 80 lbs. CaO, 20 lbs. MgO, 89 lbs. SOa, 20 lbs. Cl per acre.
** Base treatment.


Fig. 8.-Close-up view of leaves from tobacco fertilized with 3 pounds
boron per acre (left) and % pound (right).

Three pounds of boron per acre produced significantly lower
yield than 0.5 pound. Yield at the 0.5-pound rate was not sig-
nificant over the no-boron treatment. Three pounds of boron per







Florida Agricultural Experiment Stations


acre produced a dwarfed plant with a very brittle leaf having
glossy, reddish brown specks which often developed into larger
splotches (see Figure 8). The tobacco ripened slowly and, when
cured, has a dry, porous leaf of low quality.


RATES OF FERTILIZER AND VARYING NUMBER OF
PLANTS PER ACRE

The tobacco crop is very responsive to rate of fertilization.
Increased rates of fertilizer and increased numbers of plants per
acre are widely used by growers to produce higher yields and
quality.
Results of tests with different rates of fertilizer and number
of plants per acre are given in Table 16. These tests show that
with 5,026 plants per acre and fertilizer increments of 200 pounds,
there was a significant increase in yield of tobacco up to 1,800
pounds of fertilizer per acre.

TABLE 16.-EFFECT OF VARIOUS RATES OF A 3-8-6 FERTILIZER AND VARYING
NUMBER PLANTS ON YIELD AND PRICE OF TOBACCO (1939-1944).
3-8-6 Fertilizer* I Number of I Yield I Selling Price Gross
Pounds per I Plants Iper Acre I er 100 Value
Acre per Acre --Pounds Pounds per Acre

1,000** 5,026 969 $24.97 $242
1,200 5,026 971 26.06 253
1,400 5,026 1,088 25.55 278
1,600 5,026 1,153 26.01 300
1,800 5,026 1,211 25.52 309

L. S. D. (.05) 58 pounds

1,000** 5,026 1,015 25.22 256
1,200 5,326 1,099 26.30 289
1,400 5,626 1,179 26.63 314
1,600 5,926 1,241 25.62 318
1,800 6,226 1,296 25.62 i 332
L. S. D. (.0) 63 pounds
L. S. D. (.05) 63 pounds


The 3-6-8 fertilizer also supplied CaO 80 lbs., MgO 20
boron when used at 1,000 pounds per acre.
** Base treatments.


lbs., SOs 89 lbs., and 0.5 lbs.







Fertilizer Tests with Flue-Cured Tobacco


When both number of plants and amount of fertilizer were in-
creased, there was a significant increase in yield up to the 1,600-
pounds-per-acre rate with approximately 6,000 plants. See
Figure 9 for growth comparisons. Quality was uniformly good
in all tests.


Fig. 9.-Tobacco growth following two rates of fertilization. Upper, 1,000,
lower, 1,800, pounds of fertilizer. Each plot had 5,026 plants per acre.







Florida Agricultural Experiment Stations


MINOR ELEMENT STUDIES WITH TOBACCO
Minor elements have increased yields in some instances when
applied to other crops. Tests were made on tobacco with six of
the more important minor elements-copper, manganese, zinc,
cobalt, iron and boron. Results, given in Table 17, indicate that
there was no significant response to any of the elements used.

TABLE 17.-EFFECT OF THE VARIOUS MINOR ELEMENTS ON YIELD AND
PRICE OF TOBACCO (1939-1942).
Yield I Selling I Gross
Minor Elements* Added I per I Price I Value
to the Fertilizer** Acre per 100 I per
Cu Mn Zn Co Fe B -Pounds IPounds I Acre

O 0 0 0 0 0 1,245 $20.16 $251
Cu Mn Zn Co Fe B 1,210 18.84 228
O Mn Zn Co Fe B 1,139 19.58 223
Cu O Zn Co Fe B 1,125 20.44 230
Cu Mn O Co Fe B 1,220 19.26 235
Cu Mn Zn O Fe B 1,176 18.96 223
Cu Mn Zn Co O B 1,278 20.50 262
Cu Mn Zn Co Fe O 1,113 19.23 214

I Pounds Pounds
Compounds Used Elements I Compounds
per Acre I per Acre
CuSO4.5H20 Copper sulfate .................. 7.65 30.00
MnSO4.2HO Manganese sulfate ..........- 7.65 26.01
ZnSOM.7H20 Zinc sulfate ...................... 2.55 11.25
CoSO4.7H,0 Cobalt sulfate ................ 2.55 12.16
FeSO,.7HO Iron sulfate ...................... 2.55 12.65
Na2B,07.10H20 Borax .......................... 1.275 i 11.25

** A 4-8-8 fertilizer was used at the rate of 1,000 per acre and was prepared from the
following reagent grade materials: Magnesium chloride; magnesium nitrate; mono-
ammonium phosphate; di-ammonium phosphate; potassium sulphate; potassium carbonate;
ammonium sulphate; calcium nitrate; calcium sulphate; and calcium carbonate; and con-
tained the following pounds of other nutrients: MgO, 20; SOs, 125; Cl, 20. The above
materials were mixed by Dr. C. E. Bell, deceased, of the Department of Soils.

ACID, BASIC AND NEUTRAL FERTILIZERS

The question often arises as to whether acidity is important
in mixed fertilizers. Therefore, tests were made to determine







Fertilizer Tests with Flue-Cured Tobacco


the relative value of acid, basic and neutral fertilizers.2 Each of
three fertilizer mixtures was formulated to analyze 3-8-6 and
each was used at the rate of 1,000 pounds per acre in this experi-
ment. Results are given in Table 18.
There were no significant differences in yield or quality from
these mixtures.
TABLE 18.-EFFECT OF ACID, BASIC AND NEUTRAL FERTILIZER ON YIELD
AND QUALITY OF TOBACCO.
Acid, Basic Neutral I Yield I Selling Price Gross
Fertilizer* I per Acre I per 100 Value
Pounds her Acre I --Pounds I Pounds I er Acre
1,000 lbs. 3-8-6 .............. 920 $30.71 I $283
** Acid

1,000 lbs. 3-8-6 .............. 901 30.80 278
t Basic

1,000 lbs. 3-8-6 .............. 941 30.57 288
Neutral

Each treatment supplied 30 lbs. N, 80 lbs. P-Os, 60 Ibs. KaO, 80 lbs. CaO, 20 lbs. MgO,
89 lbs. SOs, 20 lbs. Cl, and 0.5 Ibs. boron per acre.
** 88 pounds equivalent acidity per 1,000 pounds mixture.
t 100 pounds equivalent basicity per 1,000 pounds mixture.

SUMMARY AND CONCLUSIONS

Fertilizer tests with flue-cured tobacco were conducted on Nor-
folk fine sand near Gainesville, Florida, during the 1939-1944
seasons.
Nitrogen stimulated growth more than any other element
tested. The optimum rate of nitrogen for tobacco in these tests
was 30 pounds per acre. Nitrogen is essential for the produc-
tion of a vigorous, leafy plant. Heavy rates of nitrogen must be
balanced with phosphorus to insure ripening and potash must
be increased to maintain good quality.
Results of single-source applications of nitrogen were not as
good as a combination of sources. A nitrogen ratio of one-third
from sodium nitrate, one-third from sulfate of ammonia and
one-third from urea produced highest yields with good quality.
Results of these tests show that fertilizers high in organic nitro-
gen are not necessary for the production of a high yield of good
quality tobacco.

Calculations of acidity or basicity according to data given by Pierre,
American Fertilizer 79: 5-8 (Oct. 21, 1933).






Florida Agricultural Experiment Stations


Small increases in yield and grade were obtained from phos-
phorus (P205) up to 80 pounds per acre. Higher rates reduced
yields slightly, although the quality was good. These lower
yields probably resulted from hastening of maturity by high
phosphorus.
Rates of potash may be economically increased from 60 up to
at least 110 pounds per acre. Higher rates of potash delayed
flowering of tobacco. The 110-pound rate of potash used with 40
pounds of nitrogen gave better results than 60 pounds of potash
used with either 30 or 40 pounds of nitrogen.
Eighty pounds of calcium (CaO) and 20 pounds of magnesium
(MgO) appeared to be adequate for good yield and quality. There
were no deficiency symptoms observed with either of these treat-
ments.
No response to sulfur (SO3) was observed, except a slight in-
crease in yield from high rates of sulfur combined with equally
high rates of potash.
A fertilizer carrying 20 pounds of chlorine per acre was better
than one with none or another with 40 pounds.
With plant number either constant or varying with the ferti-
lizer, there was a steady increase in yield up to 1,800 pounds of
3-8-6 per acre.
Minor elements were not found to be beneficial. One-half
pound of boron per acre increased yield slightly without any re-
duction in quality, but the increase was not significant.
Acidity or basicity of the fertilizer had no significant effect in
these experiments.

SUGGESTED PRACTICES
Other tests conducted at the same time, but not reported in
this bulletin, and general observations provide the basis for the
following suggested practices. (1) Fertilizer should be applied
a week or 10 days ahead of transplanting. (2) Side placement
is preferred, but if the fertilizer is to be applied in the drill row
it should be thoroughly mixed with the soil. (3) It is not neces-
sary, and often not advisable, to put out the entire amount of
fertilizer at one time, because leaching rains may occur during
the early part of the season and additional fertilizer would be
needed for the best growth. (4) A side-dressing may be used
very satisfactorily during the first month of growth. (5) If
higher rates of fertilizer are to be used it is important that the
chlorine content be held to not more than 2 percent. (6) Most







Fertilizer Tests with Flue-Cured Tobacco


of Florida tobacco soils have a pH of approximately 5.6 and it is
possible to use on these soils up to 30 pounds of chlorine per acre
without harmful effects. (7) Judicious use of nitrogen should
be practiced at all times for best results.
Tobacco should not be grown directly after a legume, since it
is difficult to predict the amount of nitrogen needed in the com-
mercial fertilizer under this condition.

CURRENT FERTILIZER RECOMMENDATIONS
The data reported in this bulletin and conclusions drawn are
approximately the same as those recommended by the Agronomy
Work Conference Committee for all types of flue-cured tobacco.3
A 3-8-8 fertilizer containing a 2 percent magnesium (at least
one-half water-soluble) and 2 percent chlorine is recommended.
The value of water-insoluble organic sources of nitrogen in to-
bacco fertilizer mixtures is questionable. Such sources of nitro-
gen' as cottonseed meal, soybean meal and dried blood are more
desirable than many other organic. The cost of these organic
sources of nitrogen adds appreciably to the cost of the fertilizer
and does not greatly affect yield and value of the tobacco crop.
It is recommended that the phosphorus in tobacco fertilizer
be derived from superphosphate and the potassium from sulfate
of potash, sulfate of potash magnesia and muriate of potash in
such proportions as to supply the necessary magnesium and
chlorine. Calcium and sulfur are important in tobacco nutrition
and are supplied in the fertilizer mixture when the preceding
sources of materials are use.
Rate of application should be from 1,000 to 1,600 pounds per
acre, depending on the soil type and organic matter content of
the soil.
Numbers of plants per acre should vary from 5,000 to 7,000,
depending upon rate of fertilizer, soil type and moisture-holding
capacity. Row width and plant spacings required for 5,000
plants per acre are: 48 x 26 inches or 42 x 30 inches; for 6,000
plants, 48 x 22 or 42 x 25 inches; for 7,000 plants, 48 x 18.5
inches or 42 x 21.5 inches.





3 Agronomy Work Conference composed of Tobacco Research Workers
from the principal flue-cured tobacco producing states.




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