A Fertility Program for C.elery Production


 Differences represented by the five-year averages of the sub-
sequent crops on Area 2 were significant statistically, with
calculated odds of more than 50 to 1. This means that for
every one of these five crops there were striking differences in
yield in favor of the fertilizer containing nitrogen, and that
the average difference for this period was 75 field crates of
marketable celery per acre. Since in this area the nitrogen used
was half from castor pomace [with a cost to the grower of
37.1c per pound of nitrogen (4)] and half from ammonium sul-
fate [with a cost of 9.8c per pound of nitrogen (4)], the total
cost per acre for the nitrogen alone in the 3% fertilizer was
$28.16. All strippings were removed from the plots each year
in this area and the fertilizer was supplied at the rate of 2,000
pounds per acre before planting, with an additional 2,000 pounds
per acre applied later as side-dressing.
 The total growing cost per acre, including fertilizer (4), for
each year of this five-year period was as follows for the two
fertilizer combinations used in this comparison:
 Without With 3%
 nitrogen nitrogen
 Growing cost (see Table 1) ........................... $159.55 $159.55
 Superphosphate ............... .... ............. 9.52 9.52
 Sulphate of potash ................................ .... 12.74 12.74
 Castor pomace ....... ..........- .............. .. 0 22.28
 Sulphate of ammonia ................ ........ ...... 0 5.88
 Mixing cost @ $3.50 a ton (4) .............. 7.00 7.00
 Total cost per acre ............................ .. $188.81 $216.97
 Comparative average yields, Fig. 4, were 435 and 510 field
crates per acre, respectively, for those two treatments and for
five different crops of celery. The growing cost per field crate
of marketable celery produced (Table 2) was nearly the same
for each of these two treatments. Actually, the cost per crate
without nitrogen was 43.4c, as compared with 42.5c per crate
where nitrogen was used. There were, therefore, 75 crates more
per acre produced where nitrogen was added to the fertilizer,
at a slightly lower cost per crate. If we assume a return to
the grower of 50c per field crate, the total return per acre with-
out nitrogen would be 8217.50, with nitrogen $255.00. For the
former the net profit per acre would be 8217.50 minus 8188.81,
or $28.69. For the treatment with nitrogen the comparable
net profit would be 8255.00 minus $216.97, or $38.03. Nitrogen
in the fertilizer would, therefore, increase the net profit per
acre by $9.23, assuming a return of 50c per field-trimmed crate.