Florida Agricultural Experiment Station


 Table 3 has been included to emphasize the economic advant-
age of the use of potash fertilizers for celery. Here, as in the
discussion of nitrogen fertilizers, the cost of the fertilizer was
taken from the 1937 report of the State Chemist (4), the
standard mixing charge has been added, and the total added
to the basic figure found previously to represent the costs of
carrying celery through to the field-trimmed crate, all on the
"per acre" basis. The rate was one ton of fertilizer to the acre
applied before planting and one ton per acre as side-dressing
when the crop was partly grown. The cost of both tons has
been included, although it has been found that in the event strip-
pings are not removed from the field the fertilizer added as
side-dressing would not have been necessary. The advisability
of such a procedure is discussed in the latter part of this bulletin.
 Returning to the discussion of Table 3, again it has been
 assumed that the marketable celery brought a gross return to
 the grower of 50c per field-stripped crate, in order to compare
 the several treatments listed from the standpoint of net profits
 per acre. With respect to each or any comparison in this table,
 the treatment higher in potash has produced the crop with the
 lower cost per crate. Under any probable market conditions
 such a condition must make the use of the higher potash analysis
 fertilizers economical. For this reason the use of 12% potash
 fertilizers, properly mixed with nitrogen and phosphate, is sug-
 gested for commercial practice, under conditions comparable to
 those under which these crops have been grown.
 Table 3 does not list any 15 or 18% potash fertilizers and
 it might be assumed, as mentioned above, that because of the
 other comparisons an analysis higher than 12% might prove
 economically feasible when applied at the same rate (one ton)
 per acre. No 0-41/-18 fertilizers were tested in Area 2. How-
 ever, a fertilizer with the approximate analysis of 0-12-18 was
 included in the experiment. In three of the five years this
 treatment outyielded the 0-41/-12 by 3, 21 and 27 crates per
 acre, while in the other two years the 0-41/-12 outyielded the
 0-12-18 by 3 and 16 crates per acre. No significance can be
 attached to such irregular results. It is also most unlikely
 that the extra phosphate depressed the yields.
 Thus it can be seen that the 6% potash fertilizer produced
 a tremendous yield response from celery compared with that
 produced by a fertilizer entirely deficient in potash; that a 12%
 potash fertilizer produced a relatively smaller but still sizeable