FLORIDA ,STATE HORTICULTURAL SOCIETY. 
Ill 
liberately impair that system to such an 
extent as to reduce its strength from 25 
to 50 per cent; yet that is what many a 
grower does time and again. During 
proper seasons land should be given shal¬ 
low cultivation to conserve moisture by 
creating a dust mulch and to avoid a 
crusting over which shuts off the circula¬ 
tion of air, but this cultivation should 
never disturb the plant’s roots. There is 
another most important reason why the 
gardener should cultivate frequently, and 
especially after a rain, and that is to keep 
the soil black. White reflects, black ab¬ 
sorbs, heat. With other conditions the 
same a dark soil is several degrees warm¬ 
er than a light one, and those few degrees 
in temperature will often increase the 
growth of the plant wonderfully. 
The plant needs in its construction 
about fourteen different elements but Na¬ 
ture makes a bountiful provision for all 
except nitrogen, phosphorus, potash and 
sometimes calcium, so we need to study 
only these which we have occasion to sup¬ 
ply. Chemistry teaches us that plant food 
is plant food wherever found, but prac¬ 
tical experience teaches us that the form 
and surroundings of that plant food have 
great influence on its effect. 
In all animal substances as well as in 
vegetable matter, the breaking down of 
existing combinations which we call “de¬ 
cay” creates more or less acidity accord¬ 
ing to the condition and surroundings 
of these substances. If there is an abun¬ 
dant supply of air, enough but not too 
much moisture, and the temperature is 
neither too high nor too low, nitrates are 
formed from the nitrogen, and the humus 
contained in the vegetable or animal mat¬ 
ter is a valuable addition to the land. So, 
under right conditions, organic sources of 
plant food, though the slowest of all “am- 
moniates” are desirable except for the cit¬ 
rus family. But if the weather be cold 
or the soil lacking in moisture the decay 
is so slow as to be scarcely perceptible, 
while if there is an excess of water, hu¬ 
mic and other deleterious acids are form¬ 
ed in place of nitrates and instead of 
plant food we have plant poison. This 
latter condition readily arises under the 
combined influences of the summer’s heat 
and heavy rains. 
We have noted the needed presence of 
certain bacteria to transform the element 
nitrogen to plant food. Their work is to 
combine oxygen with nitrogen to make 
nitric acid. After they have done this, 
it is most important that there be at hand 
a bountiful supply of base to unite with 
this nitric acid and form nitrates, and to 
neutralize, not only the nitric acid but all 
other acids. If base is lacking ft must be 
supplied before good results can be ob¬ 
tained, and it is at such times that we 
need a knowledge of the different forms 
of calcium. The form generally preferred 
is 'the carbonate of lime found in ashes 
and air-slacked lime, but the hydrated, 
the “quick” or caustic lime, and also the 
finely powdered limestone have their 
places. 
The chemical nitrates are the quickest 
acting sources of “ammonia” that we can 
apply, as they are ready for the plant’s 
use as soon as dissolved and so* deliques¬ 
cent that they invariably find enough 
moisture to dissolve them, therefore they 
are most valuable to start a quick growth, 
especially in a dry season. The great 
