xt7c2f7jrg83 https://exploreuk.uky.edu/dips/xt7c2f7jrg83/data/mets.xml   Kentucky Agricultural Experiment Station.  journals kaes_circulars_004_545 English Lexington : The Service, 1913-1958. Contact the Special Collections Research Center for information regarding rights and use of this collection. Kentucky Agricultural Experiment Station Circular (Kentucky Agricultural Experiment Station) n. 545 text Circular (Kentucky Agricultural Experiment Station) n. 545  2014 true xt7c2f7jrg83 section xt7c2f7jrg83   Q_ Circular 545
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  “·»¢~"·E"~(1200 lb.=l20 lb. P2O¤)
and under-supply the potash (10% K2O>(l200 lb.:120 lb. KQO).
Similarly, 1200 pounds of 5-10-15 would supply the nitrogen, but
over-supply the phosphate 40 pounds and the potash 30 pounds.
A thousand pounds of the 6-6-18 would provide the necessary
1 nitrogen but would under-supply the phosphate by 20 pounds
and over-supply the potash 30 pounds. In this case the 5-10-15
would best suit the needs. The excess of phosphate and potash
, in the 5-10-15 ratio is not harmful to the crop and is not objec-
tionable except for the increased cost. In other situations one
of the other two might be better.
V Mixed fertilizer high in phosphate and low in nitrogen and
potash should not be used on medium—to-high phosphate soils
because crop response on such soils will come almost entirely
from nitrogen and potassium.

 12
When using mixed fertilizers it is not always possible to V
obtain a mixture that will exactly fit the soil situation in regards
to nitrogen, phosphorus and potassium needs. In making the
final selection, remember that if the soil is deficient in phosphorus
or potassium a rapidly growing crop of high quality cannot be
produced. If nitrogen is deficient, the yield will be reduced
while an over-supply may be injurious to quality.
When the proper amount of fertilizer to give the needed
nitrogen has been determined and this amount of fertilizer does
not provide the necessary phosphate or potash, the shortage can
be supplied by the use of superphosphate or sulfate of potash.
On the other hand, when the proper amount of fertilizer necessary '
to supply the nitrogen has been calculated and more phosphate
or potash than was figured as necessary is included the excess will
not be harmful to the crop. In like manner, if the fertilizer is
calculated to give the proper phosphate and potash but does not
give sufficient nitrogen, the additional nitrogen can be obtained
from straight materials or from manure.
APPLYING FERTILIZERS
The two general methods of applying fertilizer are row and
broadcast application. Each has a place in the fertilization of
burley tobacco. The fertilizer by either method should be placed
deep enough so that it will be in moist soil during dry periods
and, hence, available to the plants. When applied along the row
it should be close enough to the plants so that it will not be
disturbed by later cultivation, yet not be directly in contact
with the newly set plants.
Row Application
On productive land where small—to-moderate applications of
fertilizers are used (less than 500 pounds per acre of mixed ferti-
lizer) all may be applied along the row at, or near, the time the .
plants are set. On less productive land when larger amounts of
fertilizer are used it may pay to apply up to 500 pounds per acre
along the row and the remainder broadcast. On soils of low
productivity this amount of fertilizer along the row may aid
materially in promoting rapid early growth of the plant, however,
on such soils this amount should not be expected to furnish the
crop with sufhcient nutrients during the later part of the growing
season. Plant nutrients. particularly phosphorus, will be more

 13
effective on the immediate crop when applied at the row than if
applied broadcast.
Broadcast Application
When more than 500 pounds of commercial fertilizer is ap-
plied per acre (see row application above) all or part should be
applied broadcast, particularly for a more even effect on succeed-
ing crops. On highly productive land all the fertilizer may be
applied broadcast. Fertilizer applied broadcast may be plowed
under with the sod if the plowing is done after the first of April,
or it may be disked or drilled in deep after plowing. However,
‘ even when carefully done, disking does not cut fertilizer into the
soil to a depth of more than 3 inches. In dry years, this may not
be deep enough for the plants to obtain full benefit from the
fertilizer. When used alone, nitrogen is probably best applied
broadcast and plowed under if the plowing is done after the
first of April.
Side-dressing with Fertilizer
If nitrogen or potassium dehciency symptoms appear early in
the growing plants, side-dressing with nitrogen or potash ferti-
lizer gives good results. However, it is much more desirable to
fertilize properly before setting since considerable care must be
taken to keep the fertilizer off the plants. When the plants are
not too large the fertilizer may be drilled on both sides of the row.
In side-dressing with nitrogen the more common practice is
to broadcast the fertilizer between the rows and work it into the
soil by cultivation. Nitrogen is very effective when applied in
this way. \Vhen side-dressing with nitrogen, however, be careful
not to apply too much, particularly when applied after the plants
have made half their growth. Additional nitrogen should not be
i applied until there is evidence of nitrogen deficiency. Even
_ though the crop starts off slowly, it is not advisable to apply nitro-
‘ gen as a side-dressing unless the tobacco shows nitrogen starvation.
Slow growth, particularly early in the season, often is due to
causes other than lack of nitrogen.
Potassium is so important to the quality of the burley tobacco
crop that it also may be profitably applied to potassium—starved
tobacco. Potash may be applied at any time from the time of
setting until the crop is too large for cultivation. However,
potash is much more effective when applied before or at setting.

 14
When side—dressing with potash the application should be larger
than normal (probably about double the normal rate), because
it cannot be applied at the depth desired nor as thoroughly mixed
with the soil as would have been possible prior to setting. To i
attempt deep placement and good mixing after the plants are
12 inches or more in height would cause considerable root injury
and further retard the growth of the plant.
Side-dressing with phosphate for burley ordinarily is not ef- -
fective enough to be practical.
DON'T OVER-LIME
‘ Excessive liming will reduce the availability of both phos-
phorus and potassium and most of the trace elements. High·
quality tobacco grown on heavily limed soils is rare. Tobacco
produced on such soil cures with the general characteristics of
potassium-starved leaf though it may not have shown bronzing
of the leaves in the held. Potash additions, adequate for normal
liming, would be inadequate on overlimed soil. _
Heavy liming may reduce soil acidity to a point where the
minor nutrients that otherwise would be in good supply are
changed to forms that cannot be used by the tobacco plant. Land
where tobacco is grown in rotation should receive only the
amount of lime necessary for the legumes in the rotation, usually
% ton to l ton per acre every 3 to 4 years, and this should
follow the tobacco.
()n soils that are motlerately—to-strongly acid it may be neces-
sary to apply 2 tons of agricultural limestone per acre in order
to establish a good stand of grass and legumes to build the land
for tobacco. ()nce the proper initial liming has been made and .
the rotation established. liming as indicated in the paragraph
above should be sufhcicnt.
Land in continuous tobacco culture should be moderately acid
and should he limed as necessary to keep it from becoming
strongly acid. Usually a fall application of l ton every 4 to 5
years should do this. Not only is liming necessary for satisfactory '
growth of the cover crops. but tobacco may be severely injured by
large amounts of soluble manganese and perhaps aluminum in
strongly acid soils.
Manganese toxicity appears first as a light green or yellowish
coloring between the larger veins of the leaf with, in some cases,

 15
a gradual development of numerous dead spots. The symptoms
usually appear first in the growing points of young tobacco leaves.
In many cases of manganese toxicity the plants lose their toxic
A symptoms with good growing weather and appear normal. Qual-
ity, however, has been lowered and the plants contain abnormal
amounts of manganese. Applying lime around the plants when
the toxicity first appears has been ineffective. Liming with agricul-
tural limestone at the rate of 1 ton per acre after the tobacco
crop usually prevents recurrence of the toxicity the following
year.
The development of soluble manganese in toxic amounts in
the soil is usually due to an increase in soil acidity to the point
that the soil tests strongly acid and to poor soil structure. If
manganese toxicity has become a problem, it would be better A
to lime the land properly following the tobac