Soils Department Mimeo Report 62-1
FERTILITY STATUS OF SOILS
USED FOR CIGAR-WRAPPER
TOBACCO PRODUCTION IN FLORIDA
W. L. Pritchett and H. L. Breland
Soils Department Mimeo Report 62-1
Fertility Status of Soils used for Cigar-Wrapper Tobacco in Florida
W. L. Pritchett and H. L. Breland1
Cigar-wrapper tobacco is intensively cultivated and a relatively expensive
crop to produce. Production costs have been estimated to be in excess of $2,000 per
acre annually. The cost of erecting and maintaining cloth shades, the need for
many hours of hand labor and the use of large amounts of manures and fertilizers all
contribute to the high costs of production of wrapper tobacco.
Although commercial fertilizers and manures account for a sizeable portion of
the total cost of production, there has been a reluctance on the part of the grower
to change or economize on these materials as long as the possibility existed that
such action might result in reduced yield or quality. The possibility of using
soil analysis as a guide for more efficient fertilizer use in cigar-wrapper
tobacco production has been an objective of research work conducted at the North
Florida Experiment Station during the past several years. Although considerable
progress has been achieved, it was thought that a survey of the fertility status of
commercial shades would aid in the application of the experimental results.
Accordingly, an on-the-farm survey was conducted during the fall and winter of
1958-1959. The purpose of this survey was to obtain information on (1) the
fertility status of soils used for the production of tobacco in the area, (2) the
fertilizer practices used, (3) the relationship of soil fertility to the yield and
quality of the crop, and (4) the possibility of using soil analysis as a guide for
1Soils Technologist and Assistant Soils Chemist, Fla. Agr. Exp. Sta., Gainesville.
Methods of Procedure
Cigar-wrapper tobacco production in Florida is confined to Gadsden, Leon, and
Madison counties. However, since about 90 percent of this acreage is in Gadsden
County, this survey was limited to that area. Eighty-six shades were included in
the study. Of these, 42 were managed by cooperators of John H. Swisher and Son and
the remaining i4 were selected at random from other growers in the county. The
size of the shades varied from 2.1 to 25.0 acres, with a mean area of 9.6 acres.
The total land area under these shades was 831.2 acres. This represented about 21
percent of the acreage of cigar-wrapper tobacco grown in Florida. Provision was
made for irrigation in all shades. Although irrigation practices doubtless varied
considerably, no attempt was made to ascertain these differences. The soils were
fumigated for the 1958 tobacco crop in all except 8 shades. In 5 of these, the
soils had been fumigated in previous years.
Samples of the surface soil (0 to 6 inches) were collected from shades during
October, 1958. This was approximately 3 months after the tobacco had been
harvested. The soil had been turned and a winter cover crop had been planted in
many shades. Cocklebur or weeds were allowed to grow as a cover crop in others.
In all cases, care was taken to get 1 to 3 representative samples of surface soil
(0-6") from each shade----depending upon the size of the field and uniformity of
the soil. Each sample was a composite of 15 cores taken at random within a uniform
area of the field with a 1-inch diameter soil tube.
Soil samples were air dried, sieved and analyzed for pH and acid ammonium
acetate (pH 4.8) extractable Ca, Mg, P and K by the University of Florida Soil
Testing Laboratory according to procedures outlined by Breland.1
Data on field histories, cultural and fertilizer practices and yield and
quality of tobacco grown in the shades in 1958 were obtained through interviews
with the growers and from records of packers.
LSoils Dept. Mimeo Report No. 58-3, Nov. 6, 1957.
Soils: The lack of suitable soils outside the present tobacco-producing area
is generally conceded to be one of the principal reasons why cigar-wrapper tobacco
production in the South has been confined to a relatively small area in North
Florida and Southwest Georgia. It is reported that "tobacco requires a well-
drained soil of high fertility. The soils best suited have moderate depth, gentle
slope, and fairly porous subsoil to provide good natural drainage, both surface
and subsoil".1 However, the soils encountered in the shades varied rather widely
in their physical properties. Approximately 26 percent of the acreages in the
86 shades included in the survey was fine sands or loany fine sands while 63 per-
cent was classified as sandy loams or fine sandy loams. The three soil series
encountered most frequently in the shades were Tifton, Norfolk and Magnolia. They
represented some 20, 15 and 14 percent, respectively, of the total acreage.
However, other series encountered, in defending order of acreage, were: Orangeburg,
Marlboro, Ruston, Red Bay, Faceville, Lakeland, Goldsboro and Carnegie.
The soils also varied rather widely in productivity. In addition to
differences in native fertility among the various soil types, there were rather
wide differences in the rate of fertilizer application and accumulation of plant
nutrients in the soil. The number of years that the areas had been used for the
production of tobacco varied from 1 to 40 years. Ten percent of the shades had
been in tobacco production for 3 years or less. In this group there were 3 new
shades; however, the soils of these latter shades had previously been used for the
production of other crops during the past few years. Approximately one-half of the
shades had been used intermittently for tobacco production for 15 years or more,
and some 36 percent had been in production for 20 years or more.
Rotations: Shades are generally rotated with cover crops, to aid in the
maintenance of soil organic matter and in the control of certain diseases and
1Kincaid, R. R. Shade Tobacco Growing in Florida. Fla. Dept. of Agr. Bul. 136.
insects, or with cash crops to gain more complete recovery of the tobacco fertilizer.
Of the shades included in this survey, there were new areas in which tobacco had
not been produced previously and in which no rotation had been established. Of
the remaining 83 fields, only in 6 shades had tobacco been grown continuously for
3 to 15 years or more without an intervening cash or cover crop. Even in these
shades, weeds were generally allowed to grow during the late summer and served as
a cover for the soil for about five months.
The most popular rotation used in shades included in this study was a 2-year
rotation in which tobacco was grown in alternate years, with cover or other cash
crops during the intervening 18 months. In 61 shades representing 75 percent of
the acreage studied, a rotation of this type was followed.
In 9 percent of the acreage in these shades, a three-year rotation was
followed in which tobacco was grown two years and then left idle, or used for the
production of a summer crop, in the third year. Five shades, representing 4.6 per-
cent of the total acreage surveyed, followed a four-year rotation in which tobacco
was grown for two years and then used for production of other crops for two years.
For shades in which a rotation was followed, the alternate summer crop varied
considerably; however, cockleburs appeared to be the most popular crop. In 41
percent of the total acreage surveyed, cockleburs was the alternate crop. Corn
was planted to some 38 percent of the shade areas and weeds were allowed to grow
during the summer in 8 percent. Sorghum was grown as a summer crop in one shade
during the alternate year.
A winter cover crop was used.in most of the shades whether a rotation was
followed or not. In 60 percent of the area under shade, oats or rye were planted
in the early fall for a winter cover or green manure crop. Cockleburs or weeds
were allowed to volunteer and grow following the tobacco harvest serving as a
Cockleburs are a popular cover crop for shade tobacco production since they
are apparently less susceptible to some of the nematodes attacking tobacco. The
plant is re-seeded, but may be mechanically planted in order to insure a good stand.
They generally volunteer in May or June following a winter cover crop or in July
following tobacco. In shades used for continuous tobacco production a crop of
cockleburs is usually turned under in early winter when preparing the land for the
next crop. In alternate two-year rotations cockleburs may be left until the follow-
ing spring before they are turned under.
Living Practices: Although the tobacco plant apparently grows well at pH
levels substantially above the range (pH 5.2 to 5.6) generally recommended, there
has been a reluctance on the part of the grower to lime the soil above this level
due to the possibility of disease infestations which may be prevalent at a higher
pH. With the development of more resistant varieties this problem may not be as
serious as it has been in the past. Of the shades included in this survey, only
five fields, representing a total of 62 acres, had received any dolomitic limestone
during the past three years other than 200 pounds per acre commonly included in
the mixed fertilizer. The average application on these soils was about 900 pounds
per acre. During the same period only one shade had received high calcic limestone.
On the other hand, 19 of the 68 shades had received basic slag. The average
application of basic slag was about 1200 pounds per acre per year.
The reaction of the soil in these shades ranged from pH 4.6 to 6.2, with the
average of all shades being pH 5.3.
Fertilizer and Manures: In addition to the green manure which is usually
turned under prior to the production of shade tobacco, relatively large amounts of
animal manures are also applied to the soil 3 to 5 weeks before tobacco plants are
set. Eighty-two of the 86 shades received animal manures for the 1958 crop. The
amounts used in these shades ranged from 6 to 25 tons per acre, with an average of
12.5 tons. Only 6 percent received less than 10 tons per acre, 5 percent received
10 to 15 tons per acre, and 12 percent of the shade received 16 to 20 tons, and
7 percent received 20 tons or more of animal manures the year the shade was used
for tobacco production. Other organic material such as cottonseed meal, tung meal
and tobacco stems may also be applied to the soil in addition to the manures and
Fertilizer programs have evolved after many years of trial and error and,
consequently, they have many features in common. However, there are considerable
differences in the soil management programs followed by farmers in the area.
Base application of mixed fertilizer, made 1 to 2 weeks before planting, varied
from 1800 to 4200 pounds per acre, with an average application of 2661 pounds per
acre. There were 13 fertilizer grades used in the various shades of this study.
The 6-6-6 and the 6-3-7 grades were the most popular and accounted for 37 and 29
percent, respectively, of the total fertilizer tonnage. Other grades used were
4-h-8, 6-3-6, 5-5-8, 6-7-7, 5-3-6, 6-4-10, 5-4-6, 6-4-7, 6-5-6, 6-3-6, 5-5-8 and
4-3-6. In addition to the base application of mixed fertilizer, cottonseed meal
was often applied either separately or mixed with the base fertilizer.
One or two sidedressings were usually applied 1 to 3 weeks after transplanting
using the same materials as that used for the base fertilizer. The average side-
dress application of mixed fertilizers was 1500 pounds per acre. In addition,
applications of 25 to 200 pounds per acre of potassium nitrate were made in about
10 percent of the shades.
Combining all materials, except for the manures, the total nutrients applied
to an annual crop of tobacco ranged from 150 to 850 pounds per acre of nitrogen
with an average application of 262 pounds per acre. Phosphorus applications varied
from 84 to 310 pounds per acre of P205, with an average application of 129 pounds
annually. Potassium applications varied from 168 to 1338 pounds of K20 per acre
with an average application of 310 pounds.
The source and rate of nitrogen probably varied from shade to shade more than
that of any other plant nutrient. Thirteen percent of the acreage in the shade
survey received less than 200 pounds of N per acre while 77 percent of the acreage
received 200 to 300 pounds of N per acre, and more than 300 pounds were applied to
10 percent of the acreage. Nitrogen is not only the most expensive of the
nutrients applied, but also one for which the need is difficult to predict. Most
of the nitrogen is applied in the organic form in the hope that it will sustain the
plant over a period of 3 to 4 months. However the rate of availability depends on
soil and climatic conditions.
Phosphorus is used to a much less extent than nitrogen or potassium. It
accumulates in the soil, since it is not used in large quantities by the plant nor
is it readily leached from the soil. Nevertheless, relatively large amounts are
applied annually. Only seven percent of the acreage in the shades received less
than 100 pounds. Thirty-three percent received from 100 to 200 pounds; 55 percent
received from 200 to 300 pounds, and 3 percent of the shades received more than
300 pounds of P205 per acre.
Potassium from the mixed fertilizers and cottonseed meal were applied in
quantities less than 200 pounds per acre in only 4 percent of the shades; 61
percent of the shades received from 200 to 300 pounds per acre, and 35 percent
received more than 300 pounds of K20 per acre annually.
Soil Analysist It might be expected that the fertility status of soils used
for the production of an intensively cultivated crop, such as cigar-wrapper
tobacco, would vary rather widely. Not only do these soils vary in native
fertility, but the accumulation of nutrients in the soil is also influenced by the
amount of fertilizer applied annually, the number of years the shade has been in
production, and the capacity of the soil to retain nutrients against leaching.
Analysis of soil samples collected from the individual shades confirms the
rather wide variation in the fertility status of the tobacco soils. A summary of
the data obtained for pH and extractable nutrients* from the analysis of samples
from the 86 fields is given below:
*Amnonium acetate (pH 4.8) extractable.
2. CaO Ibs/A.
3. MgO lbs/A.
4. P205 lbs/A.
5. K20 Ibs/A.
322 1400 Ibs/A.
70 481 lbs/A.
11 827 lbs/A.
120 576 lbs/A.
As expected, the pH, calcium and magnesium levels are low when compared to
soils used for vegetable or field crop production. On the other hand the average
content of extractable phosphorus and potassium are quite high. Furthermore, it
should be pointed out that these data represent the ammonium acetate (pH 4.8)
extractable fraction and not total content of the soil. A more accurate picture
of the available nutrients in the soil can probably be gained from the following
table showing the percent distribution of shades within ranges of fertility status:
> 6.0 2.4
> 1000 16.5
> 300 4.7
> 120 9.4
> 45o 10.6
About 72 percent of the samples had pH values within the range (pH 5.0-5.5)
generally considered favorable for tobacco production. About 7 percent were below
this range and 21 percent had pH values above this range. A study of the
relationship of soil reaction to yield indicates that yields may increase with
increases in soil pH up to the range of 5.6-6.0. The average yield of fields with
pH values of less than 5.0 was 1262 pounds per acre. Those fields with pH values
between 5.0 and 5.5 yielded 1347 pounds per acre, while those in the range of pH
5.6 to 6.0 yielded 1376 pounds. Fields with pH values above 6.0 had an average
yield of only 945 pounds per acre.
I L IJ.. IL
Although yields dropped in fields with a pH above 6.0, the average yield of
tobacco increased as the level of extractable soil calcium increased up to the
highest category (1000 pounds of CaO per acre). However, there were little dif-
ferences in yields in soils containing 500 pounds or more of CaO.
The soils were generally very low in extractable magnesium. About 68 percent
contained less than 200 pounds of MgO per acre and 18 percent contained less than
100. Both of these categories are considered to be in the critical range. The
yield of tobacco increased from 1272 pounds in fields containing less than 100
pounds of MgO per acre to 1312, 1368, and 1586 in fields that contained 100-199,
200-300, and more than 300 pounds per acre, respectively.
Phosphorus is generally applied in tobacco fertilizers in mhch larger amounts
than is removed in the tobacco crop. Since it does not readily leach from the
soil, phosphorus has accumulated in the soil of old shades. Only 20 percent of
the samples contained less than 40 pounds of extractable P205, a level which is
considered adequate in most soils. There was an increase in average yield in
fields containing up to the 40-79 pounds of P20O and decreased at higher levels of
Potassium, as phosphorus, has accumulated in these soils. Some 46 percent
of the samples contained more than 300 pounds of extractable K20 per acre and 94
percent contained 150 pounds or more per acre. This latter amount is generally
considered to be satisfactory for most conditions. There was apparently no
relationship between potash levels in the soil and yields.
The application of high rates of fertilizers year after year tends to build-up
the level of nutrients in soils in tobacco shades. This is strikingly shown in a
series of samples of Tifton fine sandy loam collected from the Strom Farm near
Quincy. The samples were taken from a virgin area and from adjacent shades that
had been in tobacco for 2 and 15 years, respectively:
Pounds per acre of extractive
Depth of sample pH CaO MgO P205 K20
Virgin (Tifton fsl)
0-6" 4.97 21 25 Trace 22
6-12" 5.00 21 25 Trace 14
12-24" 5.18 21 25 Trace 14
New Shade (Tifton fsl)
0-6" 5.49 294 116 20 250
6-12" 4.95 252 50 Trace 297
12-24" 5.05 336 66 Trace 167
Old Shade (Tifton fsl)
0-6" 5.75 885 266 112 312
6-12" 5.32 294 66 51 335
12-24" 4.77 168 66 Trace 283
On the other hand, when all 86 soils were considered as a group; there
appeared to be very little relationship between nutrient level and the number of
years that tobacco had been grown in the sahde. This was probably due to the wide
variety of soil types and fertilizer programs represented in the various shades
included in this study.