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 Front Cover
 Table of Contents
 Review of literature
 Materials and methods
 Experimental results
 Discussion of results for three...
 Discussion of the combined analysis...
 Summary and general conclusion...
 Literature cited














Group Title: Bulletin - University of Florida Agricultural Experiment Station ; 572
Title: Yield and quality of flue-cured tobacco as affected by fertilization and irrigation
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 Material Information
Title: Yield and quality of flue-cured tobacco as affected by fertilization and irrigation
Series Title: Bulletin - University of Florida Agricultural Experiment Station ; 572
Physical Description: Book
Language: English
Creator: Clark, Fred
Myers, J. Mostella
Harris, Henry C.
Bledsoe, R. W.
Publisher: University of Florida Agricultural Experiment Station
Publication Date: 1956
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Bibliographic ID: UF00027652
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.

Table of Contents
    Front Cover
        Page 1
    Table of Contents
        Page 2
    Review of literature
        Page 3
        Page 4
        Page 5
        Page 6
    Materials and methods
        Page 7
        Page 8
        Page 9
        Page 10
    Experimental results
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
        Page 21
        Page 22
        Page 23
        Page 24
    Discussion of results for three years
        Page 25
        Page 26
        Page 27
    Discussion of the combined analysis for the three years
        Page 28
        Page 29
    Summary and general conclusions
        Page 30
    Literature cited
        Page 31
        Page 32
Full Text
tin6

Bulletin 57f


2


UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATIONS
JOSEPH R. BECKENBACH, Director
GAINESVILLE, FLORIDA


Yield and Quality of Flue-Cured Tobacco

As Affected by Fertilization and Irrigation

FRED CLARK
J. MOSTELLA MYERS
HENRY C. HARRIS
R. W. BLEDSOE

S ESTIMATED WATER REQUIREMENT M EXPECTED RAINFALL








4


zdd _!-3


MAY 1-31


JUNE I-22


PERIOD
Fig. 1.-Expected monthly rainfall and estimated monthly water require-
ment in inches for tobacco planted March 15.


TECHNICAL BULLETIN


Single copies free to Florida residents upon request to
AGRICULTURAL EXPERIMENT STATION
GAINESVILLE, FLORIDA


MARCH 15-31 APRIL I-30


March 1956










CONTENTS
Page
REVIEW OF LITERATURE ....-....--- .... .------- -- ....... ..-------------- -- 3
MATERIALS AND METHODS --.............. ... ------.-... ----. ..--- ----.--. 7
EXPERIMENTAL RESULTS .. .......-.-- .--- -- .....-- ------ 11
RESULTS FOR THREE YEARS ................. .... --.... .------- 25
COMBINED ANALYSIS FOR THREE YEARS .......--..--------- --- -...-........ 28
SUMMARY AND GENERAL CONCLUSIONS .-...... ....--------.. ..-..-...- 30
LITERATURE CITED ........ ..-..... ...... ..-.---.---------.. --.. ----- 31


Fig. 2.-Irrigated tobacco showing excellent leaf quality.








Yield and Quality of Flue-Cured Tobacco

As Affected by Fertilization and Irrigation

FRED CLARK, J. MOSTELLA MYERS, HENRY C. HARRIS
and R. W. BLEDSOE

Florida produces approximately 21,000 acres of flue-cured to-
bacco which has a cash value of over 12 million dollars annually.
This acreage is grown by approximately 6,800 farmers with an
average of slightly over three acres per grower.
Flue-cured tobacco is grown in the field during the months
of March, April, May and June, with April and May being the
peak growing months. Figure 1, which is based in part on rain-
fall records for the past 67 years at Gainesville, shows that to-
bacco planted on or about March 15 may often suffer rather
severely from a deficiency of moisture during the months of April
and May. The moisture deficiency may be even more accentuated
during years when the rainfall distribution is erratic and often
causes a reduction in yield. However, a fairly high yield of to-
bacco having poor smoking qualities is sometimes produced.
Flue-cured tobacco is generally grown in Florida on sandy soils
low in fertility and organic matter, which contain a relatively
small amount of available moisture at field capacity. These
conditions suggest the possible beneficial effects of irrigation on
producing high yields of good quality smoking tobacco.
There have been numerous fertility experiments with tobacco
in the southeastern United States, including Florida. In most
instances, these tests have been conducted under natural rain-
fall conditions. Results have varied widely from season to
season, indicating that the moisture supply may have been a
major limiting factor during many seasons.
The study of the effect of fertilization and irrigation prac-
tices on flue-cured tobacco under field conditions has been limited
to a small number of experiments. A series of experiments was
conducted at Gainesville during 1949, 1950 and 1951 to study
the influence of rates of fertilization and irrigation, as well as
of previous cropping practices, on yield and quality of flue-cured
tobacco. Results are reported in this bulletin.

REVIEW OF LITERATURE
Garner (15), Moss (20), Carr (2), McMurtrey (21), Carr and
Neas (3), Stinson and Murvin (24) and many other workers






Florida Agricultural Experiment Stations


have shown the importance of a balanced fertilizer for the pro-
duction of high yield of tobacco. As a result of research with
fertilizer ratios and rates of application, the Southern Agronomy
Research Committee for flue-cured tobacco (10) has recom-
mended rates of 800 to 1,200 pounds of fertilizer per acre. For
the more productive soils 800 to 1,000 pounds of fertilizer con-
taining 3 percent nitrogen, 10 percent phosphoric acid and 6 to
10 percent potash were recommended by the committee. For
the lighter soils 1,000 to 1,200 pounds of a mixture analyzing
3 percent nitrogen, 8 to 10 percent phosphoric acid and 6 to 10
percent potash were recommended. In addition, this committee
has recommended that the fertilizer for flue-cured tobacco should
contain 2 percent magnesium, 2 percent chlorine and not less
than 6 percent calcium (CaO). Sulfur (SO) is essential, but
large quantities of easily-soluble forms should not be used.
The average yield of tobacco in Florida for a 10-year period
1940-49 (7) was 920 pounds per acre. One of the factors that
limits high production is the lack of rainfall during the peak
growing season. (See Figure 1.) Weather records (6) show
that the annual rainfall at Gainesville has varied from 31 to 65
inches. Because of rainfall variability, it has been very difficult
to raise the average yield beyond 1,100 pounds per acre.
McMurtrey (22) and Darkis (8,9) found that adequate soil and
air moisture are cardinal requirements for the growth of good
leaf tobacco which meets exacting commercial demands. When
high rates of fertilizer are used and low rainfall occurs, a poor
quality of leaf is produced. These authors state further that
leaf produced during a dry season is dull in color, high in nico-
tine and lacking in elasticity. The tobacco has more aroma,
which is associated with gums and resins. It also has a dense
structure with a high weight per unit of leaf area and a low
fire-holding capacity. The leaf ferments or ages slowly. On
the other hand, high quality tobacco is commonly produced during
a season with an adequate amount of well distributed rainfall.
The leaf is thin, light in weight per unit of leaf area, low in nico-
tine, weak in aroma, brighter in color and low in gums and
resins, and shows an active fermentation when bulked.
Garner (16) states that for normal and rapid growth in the
field, tobacco requires well-distributed rainfall, or its equiva-
lent in irrigation. The water requirements of the plants are
high because of the expanse of foliage. He reported that the to-
bacco plant is sensitive to excessive water and will drown if the
soil remains waterlogged for too long a time. An excess of mois-






Affect of Fertilization and Irrigation on Tobacco


ture will deplete the plant food supply by leaching, particularly on
the light sandy soils of the Atlantic Coastal Plain. A liberal
supply of plant food is essential to sustain rapid growth. Gar-
ner comments further that recent advances in research have
been made with fertilization and management of tobacco which
serve to minimize the harmful effects of deficient rainfall on the
growth and quality of tobacco. He found that heavy rates of
potash and a limited amount of chlorides in the fertilizer were
both effective in increasing drought resistance. Organic matter
also was found to have a significant bearing on water relations.

I J I H, L. I LL P. E F A. L L1















Controlled studies with irrigation for tobacco are limited.
Davis (11) and Duffie (12) have reported that irrigation in
Georgia and South Carolina is gaining in popularity and growers
feel that their irrigation system is a good form of insurance.
Gaines (13) reported that irrigation with soil fumigation in-
creased yields by 620 pounds per acre, or from 1,160 to 1,780
pounds per acre. Irrigation without soil fumigation in the
same test showed an increase of 350 pounds per acre. Soil
fumigation increased yields as much as 1,000 pounds per acre in
a field heavily infested with root-knot, while in the absence of
root-knot no increase was received.
Davis (11) stated that W. H. Warrick and John Deen of
Georgia were probably the first flue-cured tobacco growers to
4-













Fig. 3.-Diagram of plot layout (one replication).







irrigate tobacco in the South. Wd studies with irrigation for tobacco arelimited an
Davis (11) and Duffie (12) have reported that irrigation in
Georgia and South Carolina is gaining in popularity and growers
feel that their irrigation system is a good form of insurance.
Gaines (13) reported that irrigation with soil fumigation in-
creased yields by 620 pounds per acre, or from 1,160 to 1,780
pounds per acre. Irrigation without soil fumigation in the



increase test showed an increase of 350 pounds per acre with an increased
fumigation increased yields as much as 1,000 pounds per acre in275.
a field heavily infested with root-knot, while in the absence of
root-knot no increase was received.
Davis (11) stated that W. H. Warrick and John Deen of
Georgia were probably the first flue-cured tobacco growers to
irrigate tobacco in the South. With irrigation they realized an
increase of 500 pounds of tobacco per acre with an increased
value of $275.






6 Florida Agricultural Experiment Stations

The influence of crop rotation on tobacco production has been
reported by a number of workers, and it was found that certain
weed and crop plants were more beneficial than others. Godfrey
(17) listed many crop plants that were immune or highly re-
sistant to root-knot. However, Graham (18) and Steiner (23)
reported later that corn and peanuts are hosts for nematodes.
These crops are often grown preceding tobacco. Bratley (1)
has reported many native weeds to be hosts for nematodes.
Clayton et al (4,5) reported six primary root diseases which
effect tobacco and found that similar cropping practices do not
work equally well for all diseases. They also found an effective
nematode control by using Spanish peanuts, oats or rye in rota-
tion. Allowing the land to grow to weeds for two years or more
was found to be very helpful, but less profitable than growing
a cultivated crop. It was also found that a winter cover crop
of oats or rye turned under increased the value of tobacco about
$50 per acre. These workers ntuted finuther that growers may
use crop rotations for disease control in two ways: (1) Wait
until the field becomes seriously diseased and then rotate crops,
or (2) observe disease developments more closely and practice
rotations with a view to keeping the tobacco soils relatively dis-
ease free.
Valleau (25) stated that the burley tobacco industry was de-
veloped on sod-tobacco rotations. However, recent develop-

Fig. 4.-General view of irrigation plots with irrigation system in place.






'A'r -!. L:. .. L. .. .





lo .w- .'. w.'-.. ., .
:* : f *' '^ f "'" '''' .l. ''' ~ -' '' /." ** .* -^*' -r *'-






Affect of Fe til;:,ti;,, and Irrigation on Tobacco


ments show that over-pasturage of sods and the gradual buildup
of nematodes are becoming serious problems in the burley to-
bacco area of Kentucky. A continuous rotation in which to-
bacco is followed by a cover crop of small grains was found to
be very helpful in maintaining organic matter, and also aided
in reducing nematode damage.
Kincaid and Reeves (19) reported that after 15 years of
continuous tobacco culture a practice of clean fallow followed
by a planting of oats in the fall gave the most consistent re-
sults for shade tobacco.
Gaines (14) reported that crop rotations are the most prac-
tical way of controlling nematodes. He concluded for best to-
bacco production the rotated crop should leave a low level
of fertility in the soil. Such crops as corn, peanuts, oats, cotton
and weeds were found satisfactory in rotations with tobacco.

MATERIALS AND METHODS
This experiment was conducted on the Agricultural Experi-
ment Station farm at Gainesville, Florida. The soil type was
Lakeland fine sand having a pH value of 5.6 to 5.8. The
experimental area had been used previously in a rotation study
which included lupines or fallow for cover crops, followed by
corn or peanuts as cultivated crops. Tobacco followed corn or
peanuts in the rotation. Advantage was taken of this previous
cropping practice to obtain information on the possible effect
of crop rotation on the yield and quality of irrigated and non-
irrigated tobacco. Throughout this bulletin the effects of lupine
or fallow for cover crops will be referred to as "cultivation"
effects and the effects of corn or peanuts in the crop rotation will
be referred to as "variety" effects. See Fig. 3 for field diagram
of one replication.
This experiment was designed to determine the effect of
(a) two rates of fertilizer, (b) two methods of fertilizer appli-
cation, (c) three irrigation treatments and (d) four cropping
practices on yield and quality of tobacco. The experimental de-
sign was a split-split-plot, replicated three times. The main-
plot divisions were based on rates of irrigation. The sub-plot
divisions were based on cropping systems arranged in an across-
the-block design. The sub-sub-plot divisions were based on
rates and methods of fertilizer application. There were five
rows per plot, with the center three rows being harvested for
yield. The harvested area of each plot was 1/306 acre in size.






Florida Agricultural Experiment Stations


The tobacco was irrigated with a portable overhead sprinkler
system. A general view of the plots with the irrigation system
in place is shown in Figure 4. Three irrigation treatments were
used: (a) no irrigation, (b) one-half inch per application and
(c) three-fourths inch per application. The irrigation interval
was determined for the one-half inch application by observing
soil moisture and plant growth. The irrigation interval for the
three-fourths inch application was the same as for the one-half
inch application. Since the one-half inch application was used
in determining the interval between both irrigation treatments,
it was presumed that the three-fourths inch rate would be ex-
cessive. The one-half inch rate was selected because this amount
of water was required to bring the soil back to field capacity
after 70 percent of the available moisture had been depleted
from the top foot of soil. It was presumed that drought symp-
toms would become apparent at this soil moisture level. The

3 APPLICATIONN ~g APPLICATION =] NO IRRIGATION TIME OF APPLICATION



14








I-



4

2


Fig. 5.-Cumulative chart showing distribution of rainfall and irrigation
during 1949 growing season for tobacco.






Affect of Fertilization and Irrigation on Tobacco


three-fourths inch rate was required to return the top 18 inches
of soil to field capacity after 70 percent of the available moisture
in this zone had been depleted. Rainfall and irrigation data for
1949, 1950 and 1951 were recorded and the data are shown in
Figures 5, 6 and 7.


4/2 4/6 4/14 4/194//23 25/2 5 5/5 / 5/1 /21 526 M /2 6/9 6/16 6/ 6G/2
Fig. 6.-Cumulative chart showing distribution of rainfall and irrigation
during 1950 growing season for tobacco.

The two rates of fertilizer used were 800 and 1,600 pounds per
acre per year with two methods of application. In one method
the total quantity of fertilizer was applied a week before trans-
planting (i.e., 800 and 1600). In the other, a split application
was made in which one-half of the fertilizer was applied a week
before transplanting and the other half was applied approxi-
mately one month after transplanting (i.e., 400 + 400 and
800 + 800).
The fertilizer was formulated to contain 60 pounds of nitrogen,
160 pounds of phosphoric acid, 160 pounds of potash, 40 pounds








10 Florida Agricultural Experiment Stations

of magnesium oxide and 40 pounds of chlorine per ton. The
following quantities of minor element materials were added per
ton: 1.9 pounds of borax, 3.8 pounds each of copper, manga-
nese and zinc sulphates.


26 M ERE
3" APPLICATION 1/2" APPLICATION NO IRRIGATION TIME OF APPUCATION

24

22

20







12
6





14 --__,.,__...._____.





3/28 4/5 4/15 4/25 5/4 5/15 5/23 6/1 6/8 6/20 6/29 7/7

Fig. 7.-Cumulative chart showing distribution of rainfall and irrigation
during 1951 growing season for tobacco.

Commercial grade fertilizer materials were used in preparing
the fertilizer. The nitrogen was supplied by sodium nitrate,
sulphate of ammonia and urea at equal rates of nitrogen. Phos-
phoric acid was supplied by superphosphate containing the
equivalent of 18 percent P20O. Potash (KsO) was supplied from
48 percent sulphate and 60 percent muriate of potash. Only
enough muriate was used to supply 40 pounds of chlorine. Ep-
som salts containing the equivalent of 16 percent MgO was used
to supply the 40 pounds of magnesium. The initial applications






Affect of Fertilization and Irrigation on Tobacco


of fertilizer were made in bands approximately six inches apart,
a week before the tobacco was transplanted.
The soil of all plots was fumigated in the drill row to control
nematodes. Ten gallons of dichloropropane-dichloropropene
(D-D) per acre was applied approximately five weeks before
transplanting.
Variety 402 was used in these tests. It is a broad-leaf type
and commonly produces a high yield of good quality leaf through-
out the flue-cured tobacco territory. All plants were selected
for uniformity of size and set March 18, March 25 and March
30 for the years 1949, 1950 and 1951, respectively. The plants
were set two feet apart in the row and the rows spaced 38
inches apart. All weak and missing plants were reset within
two or three days to insure a uniform stand.
The test plots were tractor cultivated at intervals of 10 to 14
days during the growing season. The tobacco was dusted regu-
larly with 5 percent 'DDT and/or DDD to control insects.
Leaf harvesting began May 25, 1949, June 6, 1950, and June
1, 1951. The tobacco from each plot was labeled and kept sep-
arate throughout the entire harvest. All plots were cured in the
same barn. After curing the tobacco was removed from the
sticks and placed in paper bags and stored. Approximately four
weeks after the storing, the tobacco was sorted into various
farm grades based on color, length, elasticity and other physi-
cal characteristics. The various farm grades from each curing
were weighed and kept separate. A composite sample of simi-
lar grades was made from each treatment. The samples were
then graded by official tobacco graders of the United States De-
partment of Agriculture.
For evaluation purposes total plot yields were used for yield
analysis. For quality evaluation the total weight of the top four
grades from the group classifications, primings, lugs, cutters,
smoking leaf and leaf, were used as the basis for statistical in-
terpretations.
EXPERIMENTAL RESULTS
Results of this experiment will be discussed for each of the
years, 1949, 1950 and 1951, and for the three years combined.
The yearly variation of uncontrolled factors such as amount of
rainfall, distribution of rainfall and other weather factors, adds
significance to a separate discussion for each of the years.
Measurement of treatment effects is based on both the total
yield and yield of high quality tobacco. It is important to con-













TABLE 1.--ToTi TELD OF TOBACCO IN POUNDS PER TREATMENT AS AFFECTED BY FERTILIZER RATES
TION, TRRIGATION, AND CROPPING PRACTICES, 1949, 1950, 1951.
Fernltilizer Rate andi S lit Application in Pounds p r


Previous Crop


0 08 | 400 + 400


YVTar


Lupine Corn
One-half Peanuts
Inch Fallow Corn
SPeanuts

Three- Lupine Corn
fourths Peanuts
Inch Fallow Corn
Peanuts


1 9AO


6.36
5.07
7.08
7.76

10.54
8.74
8.85
8.76

11.14
8.47
8.84
7.98


1OFn I 19;1


12.65
9.08
11.00
11.40

14.07
11.07
12.70
8.64

13.92
8.51
14.09
8.95


Y'ar


9 491 1950 1951


5.74 11.57 8.77
7.49 10.12 9.23
6.16 11.75 8.00
5.52 10.86 6.92

10.92 13.09 15.41
9.91 9.66 12.70
10.28 13.66 15.21
11.79 12.28 15.44

11.15 14.96 12.94
10.73 11.64 11.60
7.21 15.85 13.50
10.38 10.38 10.45


AND SPLIT


Acre


1600 8
Year
1949 1950 1951 1949

7.38 12.15 10.82 6.94
7.21 10.63 11.07 6.98
8.89 13.47 11.01 7.77
6.99 9.81 8.85 6.05

12.61 17.50 14.22 13.61
12.71 12.38 13.91 12.98
12.66 16.15 14.66 12.60
10.54 11.68 10.92 13.91

9.34 17.62 15.31 12.08
8.96 10.43 10.22 14.24
10.05 15.50 15.16 12.45
8.65 12.82 10.00 13.38


APPLICA-



00


00 + 8


Year
1950 I 1951


11.76
11.64
12.26
10.29

16.98
8.48
15.78
9.54

13.96
11.34
16.80
13.11


11.20
10.05
9.92
7.62

17.09
18.29
14.10
14.87

14.37
13.14
13.14
14.92


Each entry represents the total for three replications.
To convert to yield per acre multiply each entry by 102.


Irrigation
Treatment


f n er Iummer I


None


Lupine

Fallow


Corn
Peanuts
Corn
Peanuts


RO0 I 400 + 400


Year '


I I Ip -


I


Wi t S










TABLE 2.-TOTAL YIELD OF TOP FOUR GRADES OF TOBACCO IN POUNDS PER TREATMENT AS AFFECTED BY FERTILIZER RATES
AND SPLIT APPLICATION, IRRIGATION AND CR)PPING PRACTICES, 1949, 1950, 1951.


Fertilizer Rate in Pounds per Acre and Method of Application


Irrigation Previous Crop
Treatment


800


Year


Winter Summer 1949 1950 1951

Lupine Corn 1.37 2.58 4.78
None Peanuts .82 3.91 3.82
Fallow Corn 1.63 4.71 4.12
Peanuts 1.93 6.69 4.53

Lupine Corn 4.94 7.68 8.66
One-half i Peanuts 3.07 7.33 5.92
Inch Fallow Corn 4.11 4.80 6.27
Peanuts 3.34 4.74 5.42

Lupine Corn 8.55 6.45 5.57
Three- Peanuts 2.13 5.00 6.52
fourths Fallow Corn 4.89 11.88 5.50
Inch Peanuts 3.89 5.20 6.01

Each entry represents the total for three replications.
To convert to. :~r acre multiply each entry by 102.


400 + 400 I


1949

1.33
1.00
1.50
.68
7.34
7.45
6.61
9.51

8.80
7.73
2.93
6.24


Year


1600


S Year


1950 1951 1949 1950 1951

5.44 5.22 1.61 3.89 4.91
7.50 5.97 1.59 3.29 6.28
5.29 3.47 2.83 5.39 5.48
6.47 5.90 .58 3.65 4.32

8.86 14.42 8.27 12.19 11.59
6.85 10.43 6.65 9.57 10.58
10.04 12.34 8.59 6.81 11.27
5.92 12.16 4.31 5.92 9.32

9.54 9.30 7.96 13.65 10.82
6.54 8.76 2.51 4.89 8.20
7.05 11.23 4.93 7.19 10.32
6.87 7.41 4.28 7.56 7.74


800 + 800


j Year
1949 1950 1951


1.10
1.25
1.15
.29

12.00
10.89
9.89
10.79

9.28
12.75
10.13
9.05


6.20
3.58
2.85
4.81

13.63
7.11
9.04
6.78

8.05
4.64
7.44
7.01


7.19
3.01
5.88
2.06

15.57
15.49
12.45
12.49

10.24
10.37
8.70
12.21








14 Florida Agricultural Experiment Stations

sider both, as well as the interrelationships between these two
measurements.
Total yield and yield of high quality tobacco for 1949, 1950
and 1951 are shown in Tables 1 and 2. Each entry represents
the total pounds per plot for three replications of treatment.

1949 RESULTS

The analyses of variance for total yield and quality are given
in Table 3. Yield and quality differences for irrigation rates
of one-half inch and three-fourths inch per application were
highly significant over no irrigation. However, there was no
significant difference in yield or quality between the one-half
and three-fourths inch rates of irrigation.

TABLE 3.-ANALYSIS OF VARIANCE FOR YIELD AND QUALITY OF TOBACCO
IN 1949.
Degrees
Source of Variation of Mean Square
S Freedom Yield Quality

Total ........ ..... .... .. -... .....-.. 143

I Irrigation ............................ ....... 2 29.70** 58.52*"
Blocks ..... ......... .................. 2 1.29 .46
Error (a) .............. .. ......... 4 1.30 I .66
II "Cultivation"t (Lupine-Fallow) 1 .32 1.85
"Cultivation" x Irrigation ...... 2 .54 1.06
Error (b) ................... ...............- 6 .25 .36
III "Variety"$ (Corn-Peanuts) .....-- 1 .21 2.51
"Variety" x Irrigation ................ 2 .09 .44
Error (c) .......-.. ................... 6 1.31 .61
IV "Variety" x "Cultivation" .......... 1 .06 .76
"Variety x Cultivation" x
Irrigation ....... .......... ... ...- 2 .40 .54
Error (d) ............................... 6 .29 .16
V Fertilizers ........... .. ...... ........... 3 5.71** 11.30**
Fertilizers x "Variety" .............. 3 .80 2.21**
Fertilizers x Irrigation ................ 6 1.69* 4.32**
Fertilizers x "Cultivation" ......... 3 .10 .16
Fertilizers x "Variety" x ....
"Cultivation" ............................-- 3 .63 .77
Fertilizers x "Variety" x
Irrigation ................ ..... 6 .23 .38
Fertilizers x "Cultivation" x
Irrigation ... ........................... 6 .42 .38
Fertilizers x "Variety" x
"Cultivation" x Irrigation ........ 6 .27 1.14
Error (e) .........-............-............ 72 .40 1 .51
*Significant at .05 percent level.
** Significant at .01 percent level.
t "Cultivation" refers to lupine or fallow for cover crops.
: "Variety" refers to corn or peanuts in the rotation following the cover crops.






Affect of Fertilization and Irrigation on Tobacco 15

Irrigation and fertilizer had a very marked influence upon
the production of high quality tobacco. The effects of fertilizer
and "variety" and those of fertilizer and irrigation were inter-
dependent.
Fertilizer applications consisted of a 2 x 2 factorial design
with respect to rate and time of fertilizer application. The
effect of rate of irrigation and of time and rate of fertilizer
application for yield and for quality are presented in Tables
4 and 5, respectively. Each entry is based on a total of 12
plots.
There was no difference between the 400 + 400-pound split
application and the 800-pound single fertilizer application on
yield of irrigated tobacco. The 1,600-pound single application
did not produce significantly higher yield or quality, on the
average, than the split application of 400 + 400 pounds of fer-
tilizer per acre. Maximum yield and quality were obtained
with the 800 + 800 pound split application.
Under dry conditions the 800-pound single application pro-
duced higher yields and quality than the 400 + 400 split appli-
cation. Also the 1,600-pound single produced higher yields
and quality than the 800 800-pound split application.
The data have been organized on the basis of time and rate
of application to facilitate the interpretation of the effects of
these two factors on yield and are presented in Table 6. Data
on yield of high quality tobacco are presented in Table 7. Each
entry is based on a total of 24 plots.
An analysis for fertilizers and interaction of fertilizers and
irrigation and fertilizers and "variety" on yield and quality of
tobacco is shown in Table 8.
Both time and rate of fertilizer application affected yield and
quality, with effects of the two treatments being independent.
The split application, at both 800-pound and 1,600-pound levels,
and the 1,600-pound single application fertilizer gave superior
results, on the average. However, effects of rate and time of
fertilizer applications were found to depend upon the rate of irri-
gation as is evident from the mean squares for the interaction of
these factors.
Superior yields and quality were obtained from the split ap-
plication of fertilizer only under irrigated conditions. Without
irrigation no advantage was realized from the split application.
The high rate of fertilizer application produced the best yield
and the largest amount of good quality tobacco at both rates
of irrigation, but at the high rate of irrigation the increase from








Florida Agricultural Experiment Stations


TABLE 4.-YIELD OF TOBACCO IN POUNDS FROM 12 PLOTS* FOR RATES OF
IRRIGATION AND TIME OF APPLICATION OF FERTILIZER IN 1949.
I 1. Mean
Fertilizer Irrigation Irrigation Irrigation Total Yield
Rate None /2 Inch % Inch Yields per Plott


800 .................
1600 ................
400 + 400**....
800 + 800**....

Totals .........

Meant ............


26.27
30.47
24.91
27.74

109.39

2.28


36.89
48.52
42.90
53.10

181.41

3.78


36.43
37.00
39.47
52.15


165.05

3.44


99.59 2.77
115.99 3.22
107.28 2.98
132.09 3.69


To convert to yield per acre multiply each entry by 25.50.
** One-half of fertilizer applied one week prior to transplanting, the other half applied
approximately four weeks after transplanting.
f LSD at .05 percent probability for irrigation means = .64.
$ LSD at .05 percent probability for fertilizer means = .29.

TABLE 5.-YIELD OF HIGH QUALITY TOBACCO IN POUNDS FROM 12 PLOTS* FOR
RATES OF IRRIGATION, RATES AND TIME OF APPLICATION OF
FERTILIZER IN 1949.


Fertilizer Irrigation Irrigation i
Rates None % inch 1

800 .............. 5.75 15.46
1600 -............. 6.62 27.82
400+ 400**.... 4.51 30.91
800 + 800**.... 3.79 43.57


Totals

Meant


Irrigation
% Inch

19.46
19.68
25.70
41.21


20.67 117.76 106.05

.43 2.45 2.21


IMean
Total Yield
Yields per Plott

40.67 1.12
54.12 1.50
61.12 1.70
88.57 2.46

244.48 i


To convert to yield per acre multiply each entry by 25.50.
** One-half of fertilizer was applied one week prior to transplanting, the other half applied
approximately four weeks after transplanting.
t LSD at .05 percent probability for irrigation means = .46.
1 LSD at .05 percent probability for fertilizer means = .33.

TABLE 6.-YIELD OF TOBACCO IN POUNDS PER 24 PLOTS*AS AFFECTED BY
TIME OF FERTILIZER APPLICATION AND IRRIGATION AND RATE OF
FERTILIZER AND IRRIGATION IN 1949.


Irriga- Irrigi
Treatment** tion tion
None %/ Inc

Time of Singlet 56.74 85.4:
Application
Split 52.65 96.0(


Rate of 800 51.18 79.79
Application
1,600 58.21 101.62


a- Irriga- I I Mean
tion Total Yield
%h % Inch Yield per Plot


73.43 215.58 2.99

91.62 240.27 3.37

75.90 206.87 2.87

89.15 248.98 3.46


* To convert to yield per acre multiply each entry by 12.75.
** Differences between times and between rates of applications are highly significant.
t All fertilizer applied before transplanting.
$ One-half of fertilizer applied before transplanting and one-half four weeks later.


L







Affect of Fertilization and Irrigation on Tobacco


the additional fertilizer was less than that obtained from the
one-half inch rate of irrigation. Based on 1949 data, the 800 +
800-pound split application of fertilizer with the one-half inch rate
of irrigation gave best results.

TABLE 7.-YIELD OF HIGH QUALITY TOBACCO IN POUNDS PER 24 PLOTS* AS
AFFECTED BY TIME OF FERTILIZER APPLICATION AND IRRIGATION AND
RATE OF FERTILIZER AND IRRIGATION IN 1949.
I Irriga- Irriga- Irriga-
Treatments** tion tion tion Total Average
I None %1 Inch 3% Inch
Time of Singlet 12.37 43.28 39.14 94.79 1.31
Application J I
Applic Splitt 8.30 74.48 66.91 149.69 2.08

Rate of 800 10.26 46.37 45.16 101.79 1.41
Application 1 1
S1,600 10.41 71.39 60.89 142.69 1.98
To convert to yield per acre multiply each entry by 12.75.
** Differences between times and between rates of applications are highly significant.
f All fertilizer applied before transplanting.
: One-half of fertilizer applied before transplantirg and the other half four weeks later.

The effect of "variety" (corn or peanuts) on yield was not
significant. However, a higher quality of tobacco was pro-
duced when planted after corn. Highest yield of good quality
tobacco was obtained on the corn plots with the split application
of fertilizer. This differential response accounts for the highly
significant interactions of fertilizer and "variety" and, specifi-
cally, of time of fertilizer application and "variety."

TABLE 8.-BREAKDOWN OF THE ANALYSIS FOR FERTILIZERS AND INTERACTION
OF FERTILIZERS AND IRRIGATION AND FERTILIZERS AND "VARIETY" ON
YIELD AND QUALITY OF TOBACCO IN 1949.
Degrees
Source of Variation of Mean Square
SFreedom Yield ( Quality
I Fertilizers .....-...... ...........- ....... ... 3 5.71** 11.30**
Time of application ................... 1 4.23** 20.93**
Rate of application ...................... 1 12.31** 11.62**
Rate x time of application .....-- 1 .61 1.36
II Fertilizer x irrigation ....-...... 6 1.69** 4.32**
Time of application x irrigation... 2 2.68* 7.88**
Rate of application x irrigation.... 2 1.16 3.26**
Time x rate x irrigation ............ 2 1.26* 1.82*
III Fertilizer x "variety" ................ 3 6.64
Time of application x "variety".... 1 2.21**
Rate of application x "variety"... 1 .30
Time x rate x "variety" ............... 1 .02
Error (e) ... -............................ 72 .40 .51
Significant at .05 percent level.
** Significant at .01 percent level.







Florida Agricultural Experiment Stations


TABLE 9.-ANALYSIS OF VARIANCE FOR YIELD AND QUALITY OF TOBACCO
IN 1950.


Source of Variation


Total .........
I Irrigation .........
Blocks ........................
Error (a) ... ..........................

II "Cultivation"t (lupine-fallow) ....
"Cultivation" x irrigation .......
Error (b) .. .............................

III "Variety"$ (corn-peanuts) ...........
"Variety" x irrigation ..................
Error (c) .............................

IV "Variety" x "cultivation" ..........
"Variety" x "Cultivation" x
irrigation ........-...... .-....... .......
Error (d) .......................... ..

V Fertilizers ................ ....... ........
Fertilizers x "variety" ..................
Fertilizers x irrigation ..............
Fertilizers x "cultivation" ........
Fertilizers x "variety" x
"cultivation" ............. ............
r'ertilizers x "variety" x irrigation
Fertilizers x "cultivation" x
irrigation ....................... ......
Fertilizers x "variety" x
"cultivation" x irrigation .......
Error (e) .............-.. .........


Degrees
of Mean Square
Freedom Yield IQuality

143
2 5.01 15.61
2 4.42 5.47
4 7.64 3.12

1 .01 1.41


.22
1.17

49.58**
3.70
.06

.34

.29
1.23

2.86*
.40
.32
.60

.07
.53

.78

.66
.34


3.27
.81

10.47**
4.37**
.28

2.03

.25
.39

1.28**
.62*
1.23**
1.40**

1.66**
1.16**

.88**

1.20**
.22


Significant at .05 percent level.
** Significant at .01 percent level.
t "Cultivation" refers to lupine or fallow for cover crops.
t "Variety" refers to corn or peanuts in the rotation following the cover crops.


TABLE 10.-YIELDS OF TOBACCO IN POUNDS PER 12 PLOTS* FOR RATES OF
IRRIGATION WITH RATES AND TIME OF APPLICATION OF FERTILIZER IN 1950.
SI Mean
Fertilizer Irrigation Irrigation Irrigation Total Yield
Rates None %2 Inch % Inch Yield Per Plott

800 ............ 44.13 46.48 45.47 136.08 3.78
1600 .............. 46.06 57.71 56.37 160.14 4.45
400 + 400**.... 44.30 48.69 52.83 145.82 4.05
800 + 800**... 45.95 50.78 55.21 151.94 4.22

Totals ....... 180.44 203.66 209.88

Meant ............ 3.76 4.24 4.37
To convert to yield per acre multiply each entry by 25.50.
** One-half of fertilizer applied one week prior to transplanting, the other half approxi-
mately four weeks after transplanting.
t LSIY at .05 probability for irrigation means + .32.
$ LSD at .05 probability for fertilizer means + .22.







Affect of Fertilization and Irrigation on Tobacco


1950 RESULTS
The analysis of variance for total yield and quality for 1950
are presented in Table 9. Irrigation did not significantly affect
total yield or quality in 1950.
Yield and quality of tobacco were higher, on the average, on
the corn plots than on the peanut plots. The highly signi-
ficant interaction of "variety" and irrigation may be explained
by the fact that more high quality tobacco was obtained on the
corn plots than on the peanut plots with irrigation. Without
irrigation there was no difference in the amount of high quality
tobacco produced.
Yield and quality data, based on irrigation, and rate and time
of fertilizer application are shown in Tables 10 and 11. Each
entry is based on a total of 12 plots.
The 1,600-pound rate of fertilizer was superior to the 800-
pound rate. There was no significant difference in quality im-
provement between 1,600 pounds of fertilizer applied at one time
and the split applications of 400 + 400 and 800 + 800 pounds.
Eight hundred pounds applied at one time resulted in the lowest
yield and quality of all fertilizer treatments.
A reorganization of the data based on time and rate of fer-
tilizer application, for yield and quality, is shown in Tables 12
and 13, with each entry based on a total of 24 plots.
An analysis for the effects of time and rate of fertilizer ap-
plications and interactions of fertilizer and irrigation, fertilizer
and "variety" and fertilizer and "cultivation" for both yield and
quality is presented in Table 14.
Fertilizer treatments influenced total yield of tobacco inde-
pendently of "cultivation" practice and irrigation rates. Signi-
ficant response to fertilizers appears to be associated primarily
with rate of application. Fertilizer applications of 800 and
1,600 pounds, all applied before transplanting, gave best response
with one-half inch irrigation, while the split application rates
of 400 + 400 and 800 + 800 pounds gave best response with
three-fourths inch irrigation. The split applications of fertilizer
appeared to give the best average response, but differences were
non-significant.
The response to fertilizer as measured by yield and quality may
be interpreted in terms of effect of rate and of time of appli-
cation. Split applications significantly increased production of
high quality tobacco. However, the interaction of time and
irrigation was highly significant. It is evident from Table
12 that best response to the split application is obtained from







Florida Agricultural Experiment Stations


TABLE 11 -YIELDS OF HIGH QUALITY TOBACCO IN POUNDS PER 12 PLOTS*
FOR RATES OF IRRIGATION WITH RATES AND TIME OF APPLICATION
OF FERTILIZER IN 1950.
1 1 1 | IMean
Fertilizer Irrigation Irrigation Irrigation Total Yield
Rates None % Inch % Inch Yields per Plot$

800 .......... -17.89 24.55 28.53 70.97 1.97
1600 ............ 16.22 34.49 33.29 84.00 2.33
400 + 400**.... 24.70 31.67 30.00 86.00 2.39
800 + 800**.... 17.44 36.56 27.14 81.00 2.25

Totals ........... 76.25 127.27 118.96

Meant ......... 1.59 2.65 2.49 _
To convert to yield per acre multiply each entry by 25.50.
** One-half of fertilizer was applied one week prior to transplanting, the other half approxi-
mately four weeks after transplanting.
SLSD at .05 probability for irrigation means = .49.
$ LSD at .05 probability for fertilizer means = .27.

TABLE 12.-YIELDS OF TOBACCO IN POUNDS PER 24 PLOTS* AS AFFECTED BY
TIME OF FERTILIZER APPLICATION AND IRRIGATION, AND RATE OF
FERTILIZER AND IRRIGATION IN 1950.


Treatments**


Time of Singlet
Application
SSplits


Rate of 800


Irriga-
tion
None


Irriga-
tion
12 Inch


90.19 104.19

90.25 99.47


88.43 95.17


IAverage
Irriga- Total Mean
tion Yield Yield
% Inch per Plot

101.84 296.22 4.11

108.04 297.76 1 4.13


98.30 281.90


Application |
Applitin 1,600 92.01 108.49 111.58 312.08 4.33

*To convert to yield per acre multiply each entry by 12.75.
** Difference between rates of application is highly significant.
t All fertilizer applied before transplanting.
$ One-half of fertilizer applied before transplanting, one-half one month after trans-
planting.

TABLE 13.-YIELDS OF HIGH QUALITY TOBACCO IN POUNDS PER 24 PLOTS' AS
AFFECTED BY TIME OF FERTILIZER APPLICATION AND IRRIGATION,
AND RATE OF FERTILIZER AND IRRIGATION IN 1950.
SI Average
I Irriga- Irriga- IIrriga- Total Mean
Treatments** tion tion tion Yield Yield
_None 1/2 Inch %4 Inch i per Plot

Time of Singlet 34.11 59.04 61.82 154.97 2.15
Application
Application lit, 42.14 | 68.23 57.14 167.51 2.33

Rate of 800 42.59 56.22 58.53 157.34 2.19
Application
Ap1,600 33.66 71.05 | 60.43 165.14 2.29
To convert to yield per acre multiply each entry by 12.75.
** Difference between times of application is significant.
t Total rate of fertilizer applied before transplanting.
$ One-half of fertilizer applied before transplanting, one-half one month after trans-
planting.


.


- -


I







Affect of Fertilization and Irrigation on Tobacco


the one-half inch rate of irrigation. On the other hand, the
high rate of fertilizer application, on the average, did not ap-
preciably increase yield of quality tobacco. However, the inter-
action of rates of fertilizer application with irrigation, with
"variety" and with "cultivation", all were highly significant.
Table 13 shows that best response to high rates of fertilizer is
manifested with one-half inch irrigation.

TABLE 14.-BREAKDOWN OF THE ANALYSIS FOR FERTILIZERS, INTERACTIONS
OF FERTILIZER AND IRRIGATION, FERTILIZER AND "VARIETY", AND
FERTILIZER AND "CULTIVATION" IN 1950.
Degrees
Source of Variation of Mean Square
Freedom I Yield I Quality
I Fertilizers ........-. ...... .... ... ..-..... 3 8.58 3.83
Time of application ..--......-..-- .. ----1 .02 1.09*
Rate of application .-...----..--..-.--- 1 6.33** .42
Rate x time of application ........ 1 2.23* 2.32**
II Fertilizer x irrigation ................... 6 8.44
Time x irrigation ..---.....--...........- 2 1.23**'
Rate x irrigation ............................ 2 2.95**
Tinie x rate x irrigation ................ 2
III Fertilizer x "variety" ................ 3 1.85
Rate x "variety" .......................... 1 1.82"*
Time x "variety" -.----....---..-------. 1 .00
Rate x time x "variety" ............... 1 .03
IV Fertilizer x "cultivation" ......... 3 3.67
Time x "cultivation" ................... 1
Rate x "cultivation" ................... 1 2.31**
Rate x time x "cultivation" ...... 1 1.31*
Error (e) ..--......----.....--.......... ........ 72 .34 .22

Significant at .05 Level.
** Significant at .01 Level.

The better responses to high rates of fertilizer as measured
by quality were obtained when tobacco followed lupine and corn
in cropping practices. The differential responses of effects of
rate of fertilizer applications under the different levels of irri-
gation and cropping practices account for the significant inter-
actions.
1951 RESULTS
Total yield and high quality yield of tobacco in 1951 were de-
termined in the same manner as in 1949-1950. Yield and quality
data are shown in Tables 1 and 2.
The analysis of variance for yield and quality are presented
in Table 15. Irrigation affected both yield and quality signi-
ficantly in 1951.







22 Florida Agricultural Experiment Stations

Total yield and good quality yield were higher, on the average,
on the corn plots. This result was the same for each of the
three years of the experiment. This fact is difficult to explain
because cropping ("variety") influence was residual.

TABLE 15.-ANALYSIS OF VARIANCE FOR YIELD AND QUALITY OF
TOBACCO IN 1951.
Degrees
Source of Variation of Mean Square
Freedom Yield Quality

Total ... .....- ...........- .................. 143
I Irrigation ............ .... ........... 2 24.61** 50.67**
Blocks .......................................... 2 1.91 4.94
Error (a) ........-.... ......--...--- 4 .92 1.07
II "Cultivation"t (lupine-fallow) .... 1 1.89 2.00*
"Cultivation" x irrigation .......... 2 .53 .56
Error (b) ....................... .............- 6 .54 .24
III "Variety" (corn-peanuts) ......- 1 7.02** 2.88*
"Variety" x irrigation ..... --. 2 .35 .25
Error (c) .....................-- .....- .-._....... 6 .13 .48
IV "Variety" x "cultivation" .......... 1 .10 .22
"Variety" x "cultivation" x
irrigation ...................................- 2 .03 .59
Error (d) .....................-...........- ... 6 .28 .47
V Fertilizers ..........-...... --....------..... 3 20.87** 12.47**
Fertilizers x "variety" .................. 3 1.13** .14
Fertilizers x irrigation ............. 6 2.42** 3.17**
Fertilizers x "cultivation" .......... 3 .46 .21
Fertilizers x "variety" x
"cultivation" ......---.. --..--------.- 3 .29 .29
Fertilizers x "variety" x irrigation 6 .76 1.80''
Fertilizers x "cultivation" x
irrigation ............................ ...... ..6 .43 .36
Fertilizers x "variety" x
"cultivation" x irrigation ....... 6 .62 .35
Error (e) ........................................ 72 .25 .31

Significant at .05 percent level.
** Significant at .01 percent level.
t "Cultivation" refers to lupine or fallow for cover crops.
$ "Variety" refers to corn or peanuts in the rotation following the cover crops.

Total yield and high quality yield data, based on irrigation
and rate and time of fertilizer applications, are shown in Tables
16 and 17. Each entry is based on a total of 12 plots.
The 800-pound single fertilizer application was significantly
lower in total production and good quality production than the
400 + 400, 1,600 and 800 + 800-pound applications. Sixteen
hundred pounds of fertilizer in one application did not signi-
ficantly increase yield or improve quality over the split applica-








Affect of Fertilization and Irrigation on Tobacco 23

TABLE 16.-YIELD OF TOBACCO IN POUNDS PER 12 PLOTs* FOR RATES OF
IRRIGATION WITH RATES AND TIME OF APPLICATION OF FERTILIZER IN 1951.
SI 1 Mean
Fertilizer Irrigation Irrigation Irrigation Total Yield
Rates None 1/2 Inch % Inch Yield per Ploti

800 ................ 29.16 33.26 33.32 95.74 2.66
1,600 .....-....... 41.75 53.31 50.69 146.15 4.06
400 + 400**.... 32.92 58.76 48.49 140.17 3.89
800 + 800**.... 38.79 64.35 55.57 158.71 4.41

Totals 1....... 142.62 210.08 188.07 540.77

Meant ......-... 2.97 4.38 3.92 __
To convert to yield per acre multiply each entry by 25.50.
** One-half of fertilizer was applied one week prior to transplanting, the other half
approximately four weeks after transplanting.
t LSD at .05 probability for irrigation means .54.
$ LSD at .05 probability for fertilizer means .23.

TABLE 17.-YIELD OF HIGH QUALITY TOBACCO IN POUNDS PER 12 PLOTS*
FOR RATES OF IRRIGATION WITH RATES AND TIME OF APPLICATION
OF FERTILIZER IN 1951.
Mean
Fertilizer Irrigation. Irrigation Irrigation ) Total Yield
Rates None ", Inch %z4 Inch Yield per Plot$

800 -............... 17.25 26.27 23.60 67.12 1.86
1,600 ............... 20.99 42.76 37.08 100.83 2.80
400 + 400**... 20.56 49.35 36.70 106.61 2.96
800 + 800**... 18.14 56.00 41.52 115.66 3.21

Totals .......... 76.94 174.38 138.90

Meant ........ 1.60 3.63 2.89
To convert to yield per acre multiply each entry by 25.50.
** One-half of fertilizer was applied one week prior to transplanting, the other half approxi-
ma'ely four weeks after transplanting.
t LSD at .05 probability for irrigation means ,58.
t LSD at .05 probability for fertilizer means .26.

TABLE 18.-YIELD OF TOBACCO IN POUNDS PER 24 PLOTS* AS AFFECTED BY
TIME OF APPLICATION AND IRRIGATION AND RATE OF FERTILIZER
AND IRRIGATION IN 1951.
Average
Irriga- Irriga- Irriga- Total Mean
Treatment** tion tion tion Yield Yield
None 1/2 Inch j % Inch per Plot

Time of Singlet 70.91 86.97 84.01 241.89 5.04
Application
Applic Splits 71.71 | 123.11 104.06 298.88 6.22

Rate of 800 62.08 92.02 81.81 235.91 4.91
Application
Applic 1,600 80.54 118.06 106.26 304.86 6.35

To convert to yield per acre multiply each entry by 12.75.
S** Differences between times and rates of fertilizer application are significant.
tAll fertilizer applied before transplanting.
$ One-half of fertilizer applied before transplanting, one-half one month after transplanting.







Florida Agricultural Experiment Stations


tion of 400 + 400 pounds. The split application of 800 + 800
pounds of fertilizer produced significantly larger total yields and
more high quality tobacco than any of the other fertilizer
treatments.
A reorganization of the data based on time and rate of fer-
tilizer application for total yield and high quality is shown in
Tables 18 and 19, with each entry based on a total of 24 plots.

TABLE 19.-YIELD OF HIGH QUALITY TOBACCO IN POUNDS PER 12 PLOTS* AS
AFFECTED BY TIME OF FERTILIZER APPLICATION AND IRRIGATION,
AND RATE OF .FERTIILIZER AND IRRIGATION IN 1951.
r Average
Irriga- Irriga- Irriga- Total Mean
Treatment** tion tion tion Yield Yield
_None /2 Inch % Inchi per Plot
Time of Singlet 38.24 69.03 60.68 167.95 3.50
Application SingleII
Application Split 38.70 105.35 78.22 222.27 4.63
Rate of 800 37.81 75.62 60.30 173.73 3.62
Application
Ap1,600 39.13 98.76 78.60 216.49 4.51
To convert to yield per acre multiply each entry by 12.75.
** Differences between times and rates of fertilizer application are significant.
t All fertilizer applied before transplanting.
t One-half of fertilizer applied before transplanting, one-half one month after trans-
planting.

A breakdown of the analysis for effects of time and rate of
fertilizer application for both yield and quality is presented in
Table 20.
Fertilizer treatments influenced total yield of tobacco inde-
pendently of "cultivation" practice. The highly significant re-
sponse to fertilizer appears to be associated with both time and
rate of application.
Fertilizer applications of 400 + 400 and 800 + 800 pounds
gave best response with one-half inch irrigation. It is significant
that with one-half inch irrigation the 400 + 400-pound ferti-
lizer application produced a higher yield than 1,600 pounds
applied at one time.
The response to fertilizer treatments as measured by total
yield and high quality may be interpreted in terms of effects of
rate and time of application. Split applications significantly
increased the quality of tobacco. However, the interaction of
time and irrigation was highly significant. It is evident from
Table 18 that the largest response was from one-half inch rate
of irrigation. Split applications of fertilizers increased both







Affect of Fertilization and Irrigation on Tobacco


yield and quality of the tobacco most with the half inch rate of
irrigation.

TABLE 20.-BREAKDOWN OF THE ANALYSIS FOR FERTILIZERS, INTERACTION
OF FERTILIZERS AND IRRIGATION AND FERTILIZERS AND "VARIETY" ON
THE YIELD AND QUALITY OF TOBACCO IN 1951.
Degrees
Source of Variation of Mean Square
Freedom Yield I Quality

I Fertilizers ................................ 3 20.87** 12.47**
Time of application ................. 1 33.01** 20.49**
Rate of application ................-...- 1 22.55** 12.79**
Rate x time of application ........... 1 7.05** 4.12**
II Fertilizer x irrigation ................ 6 2.42** 3.17**
Time of application x irrigation 2 11.20** 13.41**
Rate of application x irrigation ... 2 2.68** 5.37**
Time x rate x irrigation -_........ 2 .62 .24
III Fertilizer x "variety" ...-...-....... 3 1.13**
Time of application x "variety".... 1 1.55*
Rate of application x "variety" .... 1 .04
Time x rate x "variety" ............... 1 1.79**
Error (e) ..................................-... 72 .25 .31

Significant at .05 percent level.
** Significant at .01 percent level.

DISCUSSION OF RESULTS FOR THREE YEARS
Yield and quality of tobacco were increased by irrigation in
1949 and 1951 but not in 1950. However, the yield of good
quality tobacco was significantly influenced in 1950 by many
of the treatments and treatment interactions. The total amount
of rainfall, its distribution, and the accumulative total of irriga-
ion plus rainfall for the tobacco growing season are presented in
Figures 4, 5, and 6.
On April 6, 1949, there were approximately seven inches of
rainfall and with it there was leaching of soluble nitrogen.
This loss of nitrogen probably accounts for the split application
of fertilizer being more beneficial than the single application in
1949. The tobacco recovered from the heavy rainfall and grew
very rapidly for a few days, after which practically no growth
was made for several weeks on the non-irrigated plots because of
dry weather. The plants were severely stunted on the non-
irrigated plots. However, the irrigated tobacco continued to
grow and produced a fairly good leaf.
The early growth of the tobacco on the non-irrigated plots in
1950 and 1951 was not as severely retarded as in 1949 because







Florida Agricultural Experiment Stations


rainfall was more plentiful and distributed more uniformly. In
1949 from April 6 to May 11 there was only an inch and a quarter
of rainfall, while for the same period in 1950 and 1951 there
were approximately three inches. In 1950 from May 11 to June
17 there were three inches of rainfall, while in 1951 only 0.71
inch occurred. Rainfall distribution is very important in to-
bacco production and these data support this fact conclusively.
In 1949 the tobacco plants hardened off and flowered early,
which prevented continued growth after rain began. The unused
plant nutrients became available soon after the rains began and
caused the leaves to turn dark green and become heavily bodied.
This type of growth is typical for growing seasons such as that
which occurred in 1949. Tobacco produced under these condi-
tions is very difficult to cure and invariably produces a poor
quality of leaf.
Neither the three-fourths nor one-half inch rate of irrigation
significantly increased total yield in 1950. However, both rates
of irrigation did increase production of high quality tobacco
over the non-irrigated treatment. It is believed that the total
amount and distribution of rain and irrigation water explains
the performance of the irrigation treatments in 1950. Total
rainfall during the tobacco season for the three years was ap-
proximately 9, 16 and 9 inches for 1949, 1950 and 1951, re-
spectively. Seven, 12 and nine applications of irrigation water
were made during the 1949, 1950 and 1951 seasons, respectively.
Uneven rainfall distribution is responsible for the larger number
of irrigation applications in 1950. This summary of rainfall
and irrigation shows that approximately 65 percent more water

Fig. 8.-Irrigated tobacco fertilized with 400 + 400 pounds per acre on
left and 1,600 pounds in one application on right.



-. .. .' .. .: .





WINEi~ I
i4 ~iI-Mpg)







Affect of Fertilization and Irrigation on Tobacco


(irrigation and rainfall combined) was received by the 1950 crop
than by either the 1949 or 1951 crop. It appears that in 1950
the lack of rainfall was not the limiting factor in amount of
tobacco produced. However, it does appear that the improve-
ment in moisture distribution, by supplementing the rainfall
with irrigation water, did increase production of high quality
tobacco.
In addition to effects of irrigation, the sub-plot treatments
of cropping practices, lupine and fallow and corn and peanuts
differed. In 1949 cropping practices did not affect total yield.
However, improvement of quality approached significance when
tobacco grown on the corn plots showed an outstanding increase
in yield under irrigated conditions. The cropping practice which
included lupine and corn together with irrigation produced best
yield and highest quality tobacco for all three years. There were
no apparent economic losses from disease either year.
Yield of tobacco was significantly increased by both time and
rate of fertilizer applications in 1949 and 1951, while time was
more important in 1950. The 800-pound single application of
fertilizer produced a significantly lower yield than either of the
split applications or the 1,600-pound single application. The
800 + 800-pound split application was better than the 400 + 400-
pound split application or the 1600-pound single application. To-
bacco growth following these treatments is shown in Figure 8.
The 400 400-pound split application of fertilizer was equal to
the 1,600-pound single application in 1949 and 1951. This re-
sponse indicates the importance of split applications of fertilizer
and suggests that split applications are more desirable than in-
creasing the rate of fertilizer when irrigation is used. With irri-
gation a more uniform rate of plant growth is obtained and this
enables the tobacco plant to utilize fertilizer more efficiently.
One-half inch of irrigation water per application with split ap-
plications of fertilizer increased yield on the average more than
any other treatment for two of the three years.
Tobacco quality was much lower on the non-irrigated tobacco
for all three years. However, quality was much higher in 1951,
on the average, from all treatments than in 1949 and 1950. This
fact indicates that good yields and high quality are possible
with continuous (for at least three years) tobacco culture on
the same land, provided certain cultural practices are used. It
is believed that among these cultural practices, irrigation and
soil fumigation are two of the more important. This is of
primary concern to the grower where water and suitable tobacco







Florida Agricultural Experiment Stations


land are limited. The 800 + 800 pounds of fertilizer with the
one-half inch rate of irrigation produced on the average 81 per-
cent high quality tobacco. Without irrigation, only 35 percent
high quality tobacco was produced.
During each of the three years the total yield and high quality
yield of tobacco from the three-fourths inch per application rate
of irrigation did not differ significantly from the one-half inch
per application rate of irrigation. Thus a saving in irrigation
cost is possible with one-half inch rate. The lower rate of water
also provides a margin of safety if a rain should occur immedi-
ately after an irrigation. In 1950 the nine inches of extra rain-
fall late in the growing season definitely reduced quality on the
irrigated tobacco and greatly improved it on the non-irrigated
plots. This is one of the major problems for further study in
irrigation of tobacco.
Time and rate of fertilizer were both effective in improving
quality in 1949 and 1951, while only time of application was ef-
fective in 1950.
The highest quality was produced when lupine and corn pre-
ceded tobacco in the crop rotation and the tobacco received 1,600
pounds of fertilizer in a single application with one-half inch
rate of irrigation. The one-half inch per application rate of
irrigation produced highest yields during two of the three years
and best quality of tobacco for all three years of the tests.

A DISCUSSION OF THE COMBINED ANALYSIS FOR THE
THREE YEARS
Many of the treatment variables included in this experiment
did not perform alike during all three years. Climatic factors,
rainfall distribution in particular, are primarily responsible for
the somewhat erratic performance of certain treatments.
Nevertheless, the authors feel that an analysis of the com-
bined data for the three years will aid materially in interpreting
results and drawing conclusions. Two analyses were made. One
is based on an assumption that the years encompassing the ex-
periment are fixed years and the other is based on the assumption
that the three years encompassing the experiment represent a
random of years. The second analysis (years random) gives
information on which a very conservative prediction can be
made of treatment responses expected for future years.
The analysis for years fixed as shown in Table 21 is for general
information, but will not be discussed in detail because of the









TABLE 21.-ANALYSIS OF VARIANCE FOR YIELD AND QUALITY FOR 1949, 1950 AND 1951 COMBINED.


Source


Irrigation treatments ..........
Error (a) .... ..........-.. ... ...
Fertilizer treatments .....-..
Time of application .......
Level of application ---..
Time x level ......... .....
Fertilizer x irrigation ..--...
Time x irrigation --
Level x irrigation ......
Error (b) ..................... ..-
Years ... --...........-...
Years x irrigation .......-..- .
Years x fertilization ..--.....
Years x time ...........
Years x level ...............
Error (c) .. ---- -

Significant at .05 percent level.
** Significant at .01 percent level.


d. f.


2
4
3
1
1
1
6
2
2
18
2
4
6
2
2
48


TOTAL YIELD
Inference Based on Years


m. s.

206.24
25.16
88.01
64.13
184.71
15.19
10.16
20.02
7.48
2.44
134.83
15.62
14.88
21.55
10.95
2.18


i Fixed


Random


YIELD OF HIGH QUI
TOBACCO
Inference Based on


m. s.

460.62
3.50
74.16
137.27
77.45
7.74
24.32
36.29
35.08
3.10
147.74
19.28
13.02
16.39
10.75
1.51


Fixed Ra


ALITY

Years
ndom



*o



I
*3:






**
0

0

0
*e
s^
X~
"3
-i



**o






Florida Agricultural Experiment Stations


confined nature of any inference that could be based on this
analysis.
The analysis based on years random shows that both the one-
half inch and the three-fourths inch irrigation applications gave
significant increases in yield and quality over non-irrigated to-
bacco.
Sixteen hundred pounds of fertilizer per acre produced more
tobacco than 800 pounds, with both the high rate of fertilizer
and the split fertilizer application contributing to a significant
increase in quality. The highly significant fertilizer level and
irrigation interaction furnish evidence that without irrigation a
higher quality tobacco is produced with 800 pounds of fertilizer
per acre than with 1,600 pounds, while with either the one-half
inch or three-fourths inch rate of irrigation, 1,600 pounds of
fertilizer per acre produced better quality tobacco than 800
pounds per acre.
Differences between years are highly significant for both yield
and quality.
Table 21 shows that irrigation, amount of fertilizer, and split
application of fertilizer treatments did not perform alike during
the three years, as indicated by both yield and quality of pro-
duction.

SUMMARY AND GENERAL CONCLUSIONS
Total yield and high quality yield of tobacco were increased
by the use of irrigation during each of three years, but in 1950
the effect of irrigation treatments on total yield was not sig-
nificant.
One-half inch of irrigation water per application gave better re-
sults than three-fourths inch when the net economic benefits are
considered.
The number and distribution of irrigation applications was
dependent upon rainfall and its distribution. Seven to 12 appli-
cations were required to maintain a suitable soil moisture level
during the three years. It also appeared that 13 to 15 inches
of water (rainfall and irrigation) were necessary to produce a
satisfactory crop of high quality tobacco.
Both yield and quality of tobacco were influenced by fertili-
zation. Sixteen hundred pounds per acre of fertilizer, in two
applications, increased yield and improved quality more than
any other fertilizer variable tested. Amount and quality of
tobacco produced is favorably influenced more by the split ap-
plication of fertilizer than by the rate of application.







Affect of Fertilization and Irrigation on Tobacco


Distribution and amount of rainfall are of much importance
in the production of tobacco. This is indicated by the variable
response of irrigation and fertilizer treatments during the three
years. Based on all three years' data, a cropping practice of
lupine followed by corn and then tobacco, combined with 1,600
pounds per acre of fertilizer (800 + 800-pound split application)
and one-half inch application of irrigation produced the largest
amount of high quality tobacco.
Soil moisture from irrigation alone is insufficient to enable any-
one to predict with a marked degree of accuracy the yield or qual-
ity of leaf to be produced during any particular year. Environ-
mental factors such as temperature, diseases and rainfall have
much effect on a tobacco crop. Results of this study suggest
that irrigation should be a profitable practice in the growing of
tobacco.
ACKNOWLEDGMENTS
The writers gratefully acknowledge the helpful suggestions and assis-
tance given by Dr. W. D. Hanson, former agronomist, College of Agricul-
ture, University of Florida, presently Biometrican in charge of Biometrical
Services, USDA, Plant Industry Station, Beltsville, Maryland; also to Tom
Adams, G. J. Gann and Thomas A. Monday, field assistants, for their
splendid cooperation in managing and collecting field plot data.

LITERATURE CITED
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bacco fields. Fla. Agr. Exp. Sta. Press Bul. 629. 1948.
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tors determining type and seasonal differences. Ind. Chem. Eng.
Jour. 27: 1152-1157. 1935.
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Florida Agricultural Experiment Stations


soils under varying weather conditions. Jour. Ind. Eng. Chem. 29:
1030-1039. 1937.
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1345. 1923.
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Agr. Exp. Sta. Bul. 390. 1951.
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