Florida Agricultural Experiment Station


in the Everglades on sawgrass peat lands. Mixtures of sulfate
of ammonia and nitrate of soda, or either of these alone, should
be suitable nitrogen sources, from the standpoint of both cost
and returns.

 INFLUENCE OF POTASSIUM (POTASH) UPON YIELDS
 AND COSTS
 Natively, these soils are very low in potassium. It is, there-
fore, of the utmost importance that both the amount and the
source of potash best for celery be determined. With respect
to source, it was found in Area 1 that sulfate of potash, muriate
of potash, and hardwood ashes were all acceptable as potash
fertilizers. Kainit showed up well one year but poorly another.
According to the 1937 State Chemist's report (4), these ma-
terials cost the grower as follows:
 Sulfate of potash ........................ 5:31c per pound of K.O
 Muriate of potash .................... 3.83c per pound of K2O
 Kainit ................................ 6.25c per pound of KO2
 3% Hardwood ashes .................. 35.00c per pound of K2O
 The excessive cost, per pound of K20, makes hardwood ashes
 far too expensive for general use, although if available in quan-
 tity they are a fine fertilizer material. Kainit also is relatively
 expensive per pound of potash and this, together with the un-
 certainty attached to its results, makes it a less desirable
 fertilizer than the other two potash salts. For this reason only
 the muriate and the sulfate of potash were used with celery in
 the trials at the Experiment Station.
 Figure 5 illustrates a comparison between these two materials.
 As a five-year average the muriate of potash produced 51 crates
 per acre per year more than did the sulfate. All in all, using
 results of two years in Area 1, six years in Area 2, and two
 years in Area 3 (a total of 10 separate crop comparisons), the
 muriate of potash plots outyielded the sulfate of potash plots
 in seven cases. Statistically these differences are not considered
 significant (the statistical odds for the five-year average from
 Area 2 were 5 to 1), but from the practical standpoint it is
 clear that, because of the difference in cost of the two materials,
 muriate of potash has proven preferable to the sulfate for celery.
 With regard to the quantities of potash which must be sup-
 plied, it was found that with the first celery crop grown on
 each of the three areas a relatively low amount of potash was
 required (a 6 to 8% potash analysis fertilizer, applied broad-