Handling the Citrus Grove 
B. F. Floyd 
Mr. President, Ladies and Gentlemen : 
Handling the citrus grove from a 
physiological point of view means 
handling it from the point of view of 
the tree. It means a recognition that 
the citrus tree is a living organism; 
that it is as it is because of the heredi¬ 
tary characters within it, and because 
of the influence which the conditions 
that surround it have had upon it as 
a living organism; that these condi¬ 
tions are numerous and are complex 
in their action; that each individual 
condition exerts a particular influence 
and the tree which we obtain in the end 
is the result of the sum of all of these 
influences. 
As has been said, these conditions 
are numerous, and are complex in their 
action. At a given time, some of them 
may be exerting a beneficial influence, 
while others are exerting a detriment¬ 
al one. Again, the conditions differ as 
to the amount of influence which each 
exerts, so that the result of their in¬ 
fluence is very much the same as if we 
were to add a column of plus and minus 
quantities. In other words, within cer¬ 
tain limits, the character of growth 
which a tree makes is determined by 
a particular combination of conditions. 
When this combination or balance is 
disturbed, the growth is also disturbed. 
For example, suppose that your trees 
are growing along nicely in the fall 
and beginning to harden up properly, 
and you give them an application of 
fertilizer high in ammonia and low in 
potash that brings on a renewed 
growth. A little later a period of cold 
occurs that injures this growth. The 
application of fertilizer has thrown the 
conditions that were bringing on the 
normal fall growth out of balance, so 
that the tree is made to produce a 
type of growth that is not normal for 
the season. 
The conditions that are essential for 
the maintenance of life in the citrus 
tree are not different from those re¬ 
quired by most of the higher plants. 
They are food, water, heat, light and 
freedom. All of these conditions must 
be present for life to exist. If any 
one is entirely absent or below a cer¬ 
tain minimum, the tree cannot live at 
all. And the tree makes its best 
growth when each of these conditions 
is contributing its best influence. 
By food, we refer to those chemical 
elements contained in the raw food 
materials which the tree obtains from 
the soil and air. These chemical ele¬ 
ments are carbon, hydrogen, oxygen, 
nitrogen, potassium, phosphorus, calci¬ 
um, magnesium, iron and sulphur. 
These terms are doubtless more or less 
strange to vou, but when I mention the 
terms, ammonia, potash, phosphoric 
acid and lime, you know at once to 
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