Florida Agricultural Experiment Station


a check for $250.00 for it. This would give him a return of 50c
a field-trimmed crate for his crop, although further trimming
and repacking at the packinghouse might have reduced to 400
the number of crates actually shipped. Assuming that the total
cost to the above-mentioned grower, including fertilizers, was
$180.00, he should have a net profit of $70.00 per acre, and it is
shown in Table 2 that this celery cost him 36c a crate. If he
had received 50c a field crate for a yield of 350 crates per acre,
with the same field costs, he would have had a net loss of $5.00
an acre. Table 2 can be used to show the yield which must
be obtained at any given field cost to break even or to show a
profit at any return, per 70-pound field crate, from the packing-
house.
 It should be obvious that any outside factor, such as a market-
ing agreement which places a restriction upon the percent of
the celery grown which can be shipped, is, in effect, decreasing
the yield per acre, and must be interpreted as such in Table 2.

 INFLUENCE OF NITROGEN UPON YIELDS AND COSTS

 Despite the fact that available nitrogen is being released in
 these peat soils at all times, celery is such a gross feeder that
in no case has a crop been grown at the Everglades Experiment
Station (Areas 2 and 3) that did not show a yield response to
nitrogen fertilizers.
 Experiments comparing different materials as sources of ni-
trogen, and for the purpose of finding the amount of nitrogen
which should be added, were conducted in Area 1. It was found
that there was no increase in yield from a fertilizer analyzing
higher than 3% nitrogen when one ton or more was applied
to the acre.
 Nitrate of soda, sulfate of ammonia, and castor pomace were
 used alone and in various combinations. Over a two-year period
 there seemed to be little difference in the source of the nitrogen
 supply, whether organic or inorganic. In Area 2, at the Experi-
 ment Station, a mixture of half castor pomace and half sulfate
 of ammonia proved satisfactory, and in Area 3, a mixture of
 sulfate of ammonia and nitrate of soda gave good results. This
 latter mixture is to be recommended because of its lower cost
 per unit of nitrogen, or, on neutral or slightly alkaline soils,
 sulfate of ammonia may be used as the sole source of supply.