NORTH FLORIDA EXPERIMENT STATION
Quincy, Florida
July 8, 1963
North Florida Station Mimeo Report NFS64-1
A NEW FERTILIZER SOURCE FOR SHADE TOBACCO
by William D. Woodward
Assistant Soils Chemist
Wrapper tobacco is very demanding as far as nutritional requirements are concerned.
The properties required of a good cigar wrapper make the selection of fertilizer materials
of paramount importance. A suitable overall fertilization program has been reasonably well
established in that the grower knows about how much of each of the major elements must be
supplied in order to realize a satisfactory yield and quality, There are, however, numerous
poorly defined and difficult to control variables which we group together under the term
"weather conditions" which have in the past made it difficult to maintain the proper
relationship between plant and nutrients. New materials are becoming available which should
considerably improve this situation.
The fertilizer material, potassium metaphosphate, has been used in cigar tobacco
fertilizer trials at the North Florida Experiment Station for a period of four years. This
material is a carrier for both potassium and phosphorus and, while only slightly soluble in
water, is readily available to plants. It may be produced as a fittede" material which
can be prepared to release the nutrients at a controlled rate. This property is highly
desirable from the standpoint of the potassium since the carriers of potassium currently
in use are readily lost through leaching when subjected to excessive rainfall.
In addition to the previously mentioned advantage of greater control over nutrient
release, potassium metaphosphate contains no sulfur and for all practical purposes no
chlorine. Such fertilizer carriers as potassium sulfate and superphosphate which are
currently used in large quantities in cigar tobacco fertilization are quite high in sulfur.
There is evidence that sulfur may in some manner be linked to "tender" tobacco. It has
also been known for some time that sulfur is responsible for poor burn in tobacco and a
general lowering of quality is present in excessive amounts. The physical properties of
potassium metaphosphate are also excellent. There is apparently no tendency to take up
moisture and it does not "set-up" like most of the commercially available carriers of both
potassium and phosphorus in use at present.
This material has proven superior to the commercially available carriers of
potassium and phosphorus for shade tobacco fertilization. The results of four years
experiments with potassium metaphosphate are presented in the following tables:
CROP INDEX
Yearly Averages 4-year
Treatment 1959 1960 1961 1962 average
Cottonseed meal-steamed bonemeal-cotton bur ash 1190 1616 1280 1636 1430
Cottonseed meal-potassium metaphosphate 1292 1644 1367 1851 1538
Uramite-steamed bonemeal-cotton bur ash 1208 1520 1310 1798 1459
Uramite-potassium metaphosphate 1416 1574 1354 1847 1548
-2 -
GRADE INDEX
Yearly Averages 4-year
Treatment 1959 1960 1961 1962 average
'ttonseed meal-steamed bonemeal-cotton bur ash .744 .783 .694 .746 .742
5ttonseed meal-potassium metaphosphate .758 .806 .740 .791 .774
?amite-steamed bonemeal-cotton bur ash .785 .772 .758 .784 .775
";amite-potassium metaphosphate .795 .817 .704 .821 .784
YIELD (Lbs. Per Acre)
Yearly Averages 4-year
Treatment 1959 1960 1961 1962 average
Cottonseed meal-steamed bonemeal-cotton bur ash 1588 2066 1842 2190 1921
Cottonseed meal-potassium metaphosphate 1701 2045 1849 2340 1984
Uramite-steamed bonemeal-cotton bur ash 1541 1968 1736 2293 1884
Uramite-potassium metaphosphate 1780 1926 1926 2251 1971
Potassium metaphosphate used in conjunction with cottonseed meal as a source of
nitrogen resulted in an average increase of 7.5% of the crop index which reflects both
yield and overall quality.. In conjunction with uramite the potassium .metaphosphate raised
the crop index 6.1%.
It is apparent from the results. presented in the tables that from the standpoint
of both yield and quality, potassium metaphosphate is superior to potassium and phosphorus
carriers in current use. Fertilizer manufacturers are continuing to work on a process
whereby this product can be made economically. Such satisfactory results as these with
wrapper tobacco will undoubtedly lead to more markets for this new material. Unfortunately,
it is not commercially available at present.
wdv
7/31/63
250 cc
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