A Fertility Program for Celery Production


 INFLUENCE OF VARIOUS "TRACE" ELEMENTS
 UPON CELERY YIELDS
 It has been known for years that all plants require small
amounts of several trace elements for satisfactory growth. Of
these, at least a few are not present in quantities sufficient for
celery in Everglades organic soils. Trace elements which are
known to be low are manganese, zinc and copper, and possibly
boron in some areas. There may be others, but their need has
not yet been satisfactorily demonstrated. Areas 1 and 2 were
used for studies of the effect of trace elements upon celery
yields.
 Of these trace elements, manganese seems to be the one
most commonly found deficient in these organic soils with re-
spect to most truck crops. The availability of manganese, like
that of phosphate, is partially dependent upon the degree of
acidity or alkalinity of the soil. However, experiments have
shown that there is an absolute deficiency of manganese in these
soils, regardless of their reaction, inasmuch as celery has shown
a decided response to manganese even on the unburned soils.
Therefore, it is recommended that 100 pounds per acre of man-
ganese sulfate be applied with the fertilizer to these soils the
first year celery is grown, provided no manganese has been
previously added to the land. For succeeding years much less
will be required and probably 25 pounds per acre should be
sufficient. Alkaline burned soils will require more than will
the normal soils of the area.
 Manganese can be supplied also combined with the bordeaux
sprays which should be applied weekly for the control of early
blight. It is known that this method is satisfactory for some
other crops. It is suggested that four pounds of 83% man-
ganese sulfate be added to 50 gallons of spray solution (5), and
used in this manner for the first three or four weekly sprays
in the event that no manganese is applied with the fertilizer.
It is not desirable to delay the application of manganese until
the plants show a deficiency in the field, since by that time the
plants are already severely injured and will never make the crop
that they would have made had the manganese been supplied
earlier.
 Zinc is another trace element which can be added in fertilizer
applied to Everglades organic soils. The requirement of celery
for zinc is not large, but the addition of 25 pounds of zinc