FLORIDA STATE HORTICULTURAL SOCIETY. 
77 
erally accepted, viz: that acid phosphate 
and kainit are injurious to pineapple 
plants; it has shown that nitrate of soda 
has some good qualities and some bad 
ones; it is good as a source of nitrogen 
to start young plants, but used liberally 
on bearing fields it finally injuires the 
plants and produces a fruit which has 
poor carrying qualities; the results ob^ 
tained with the sulphates of potash, low 
and high grade, were slightly better than 
those obtained with the muriate. As 
sources of phosphoric acid bone meal and 
slag phosphate have given very good re¬ 
sults, slag apparently giving slightly bet¬ 
ter results than bone meal 
Dried blood, cotton seed meal and cas¬ 
tor pomace have all given good results as 
sources of nitrog'en, and it would be rath¬ 
er difficult to say which is the best. One 
grower may use dried blood with success, 
and perhaps another may use cottonseed 
meal or castor pomace with equally good 
or even better success. The price of the 
goods, the requirements of the individual 
etc. will necessarily come in here as deter¬ 
mining factors. And I may stop here to 
say that in this work it has been our en¬ 
deavor to show just what results the dif¬ 
ferent amounts and different kinds of fer¬ 
tilizers will give, rather than to calculate 
to a nicety which is the most economical, 
thus leaving it with the grower who is, 
in almost every instance, competent to de 
termine which is the most economical in 
his individual case. 
A THEORY FOR THE INJURIOUS EFFECTS 
OF ACID PHOSPHATE. 
Before leaving this point it may be well 
^to state that the beds which received acid 
phosphate without lime have been almost 
entirely ruined, while those v/hich receiv¬ 
ed acid phosphate and lime in addition, 
have remained in good condition and have 
given almost as good results as some 
which have been considered among the 
best. It is not an easy matter to explain 
this. However, one theory at least has 
been advanced, which is, that acid phos¬ 
phate contains sulphates of iron and alu¬ 
mina which are astringent salts, the pres¬ 
ence of which might be injurious to the 
tender rootlets of the pineapple plant. 
With the addition of lime these astringent 
salts would be neutralized with the for¬ 
mation of the harmless insoluble oxides 
of iron and alumina. This explanation 
would seem to be strengthened by the fact 
that the plots which received geniune dis¬ 
solved bone black, which does not contain 
salts of ii 1 and alumina, were not injur¬ 
ed. 
It may be objected that if the tender 
rootlets of the pineapple plant are injured 
by these astringent salts, then would not 
the rootlets of corn, cotton, wheat, etc. 
be injured in the same way? To this ques¬ 
tion I would answer no, not necessarily, 
since in the soils where these crops grow, 
there is much more lime than there is in 
the pineapple soils, probably all that is 
needed to neutralize these astringent salts. 
However I would not recommend the 
use of acid phosphate on pineapples, even 
with lime, at least until the subject has 
been further investigated. 
The excellent results obtained by the 
use of slag phosphate might possibly be 
taken as an indication that there is some 
efficacy in lime, since this material con¬ 
tains a goodly percentage of free lime. 
THE LIMIT OF PROFITABLE FERTILIZING. 
One very interesting part of the experi¬ 
ment has been the determining of the lim¬ 
it to which it is profitable to fertilize pine¬ 
apples. 
