26 FLUE-CURED TOBACCO IN FLORIDA

in supply of available potassium, depending upon fertilizer
used, cropping history, and soil type. A supply of ninety to
one hundred and forty pounds of potash (K20) per acre is
adequate for most conditions. When high potassium fertilizers
are used it is advisable to mix the fertilizer thoroughly before
transplanting, unless several days elapse between applying
the fertilizer and transplanting.
 The need for use of rates beyond the above recommendations
appears to be of little value for best agronomic growth and
economical returns in Florida. If more potash is needed this
may be supplied by sidedressing with sulfate of potash.

 Chlorine: Chlorine is not considered an essential element
for most plant growth. However, sizable quantities of this
element are found in most mixed fertilizers. It has been
shown that a small quantity of chlorine (about 20 pounds
per acre) in tobacco fertilizer increases the acre value and
yield of the crop. On the other hand, experiments have shown
that excessive amounts may injure the growth of the plant
and reduce the quality of the leaf. Excessive chlorine in the
plant results in a thick, brittle leaf which when cured be-
comes thin, soggy and dull in color. It also has an unfavorable
affect upon burning quality.

 Soil types, moisture holding capacity of the soil and the
amount of rainfall are factors that are known to influence
the uptake of chlorine. The nature and magnitude of these
influences, however, are such that they can only be given
small consideration in arriving at a satisfactory rate of chlo-
rine. It is recommended that the application of this element
be held between the limits of 20 and 30 pounds per acre.
Chlorine from all sources should be considered.

 Figure 14 shows the effect of excess chlorine on leaf develop-
ment. The use of not more than 2 units of chlorine cannot
be stressed too strongly, because if more than 30 pounds total
chlorine per acre is used, leaf thickening will result. In
addition, the hygroscopic or wetdog appearance may become
evident and the tobacco will darken during handling. For
success in both production and in marketing it is recommended
that full cooperation of all agencies is needed to hold the
chlorine content of tobacco fertilizers well within the range
of tolerance for good production and processing.