110 
FLORIDA STATE HORTICULTURAL SOCIETY 
sorghum. The sorghum was then manu¬ 
factured into syrup from both the ferti¬ 
lized and unfertilized areas with the re¬ 
sult that where no fertilizer was used, 
the yield of syrup per acre was 67 gal¬ 
lons; and where fertilizer was used, the 
yield was 140 gallons. This syrup was 
worth at that time from 90 cents to $1.45 
per gallon; hence, the gross gain even at 
90 cents would be $65.70, from which 
there must be deducted only the very 
small cost of the 100 pounds of fertilizer 
in order to show the net profit from the 
fertilization. 
Such increases often seem to be more 
than might be expected from the mere 
plant-food effect of the fertilizers; and it 
appears possible that in addition to fur¬ 
nishing plant food in immediately avail¬ 
able form in close proximity to the young 
rootlets of the plants, the fertilizers may 
also have a corrective effect by way of 
overcoming the toxicity of certain sub¬ 
stances which may be present to an in¬ 
jurious extent in some of these soils. 
Furthermore, it is now known that fer¬ 
tilizers have a very marked stimulating 
effect upon the development of certain of 
the soil bacteria upon which soil fertility 
is very largely dependent. In connection 
with the first point raised, attention 
should be called to the fact that Conner, 
Abbott, and their associates in Indiana, 
found that in some soils aluminum nitrate 
was present in sufficient amounts to be 
toxic to plants. This is a substance 
which is decomposed by either lime or 
superphosphates; and wherever such com¬ 
pounds are present in the soil, the appli¬ 
cation of fertilizer containing superphos¬ 
phate would be expected to make the con¬ 
ditions more congenial to the develop¬ 
ment of young plants. Similarly, at the 
Rhode Island Agricultural Experiment 
Station, Hartwell, Pember, Damon, and 
their associates, have found that where 
sulphate of ammonia was applied to the 
soil for a series of years as the exclu¬ 
sive source of ammonia, aluminum sul¬ 
phate had been formed in the soil in suf¬ 
ficient amounts to render the soil unable 
to longer support the growth of various 
kinds of crops. It had previously been 
shown by the author of this paper that 
the existing toxicity, regardless of its 
cause, could be entirely overcome by the 
use of lime. More recently it has been 
demonstrated by Hartwell, Pember, Da¬ 
mon, and their associates, that exceeding¬ 
ly large applications of superphosphate 
are also capable of overcoming or greatly 
reducing the toxicity of the aluminum 
sulphate; and this is due to the fact that 
the phosphoric acid upon combining with 
aluminum, changes it into a very insolu¬ 
ble form which the plant cannot assimi¬ 
late. Ruprecht, while at the Massachu¬ 
setts Agricultural Experiment Station, 
found soluble, or toxic, aluminum salts 
present in certain soils. It appears, there¬ 
fore, that this is a condition which we 
have but just begun to recognize in this 
country. In fact, it is not improbable 
that certain soluble salts of the protoxid 
of iron may have similar effects, which 
superphosphates are able to correct. 
Where sufficient quantities of soluble 
aluminum salts exist in the soil to prevent 
utterly the growth of onions, beets, let¬ 
tuce, spinach, upland cress, asparagus, 
cabbage, cauliflower, and, in fact, a 
large number of other kinds of plants, 
