FLORIDA STATE HORTICULTURAL SOCIETY 
57 
therefore, increases the water-absorbing 
or receiving capacity of the soil and in 
turn increases its power to deliver the 
goods to the growing plant. 
We must not lose sight of the fact that 
the loss of moisture under drought condi¬ 
tions is not the only loss suffered by a soil 
deficient in organic matter. A greater 
loss in many cases comes through abnor¬ 
mal leaching of essential and expensive 
plant food, especially nitrates. Our cit¬ 
rus soils, as a rule, have a very porous 
sub-soil and permit free downward pas¬ 
sage of soil water, carrying much plant 
food in solution. Leaching of nitrates is 
often the limiting factor in maximum crop 
production in a grove. This can be over¬ 
come in a large measure by deepening and 
building up the organic constituent of the 
top soil, forming a sponge-like mass to ab¬ 
sorb more plant food as it goes into solu¬ 
tion. Deep-rooting cover crops will aid 
much in building a deeper soil. Attention 
should be given to this soil building while 
the trees are young or even before the 
grove has been set. 
Adding organic matter to some of our 
sandy citrus soils is like tightening the 
hoops on a dry rain barrel. It is said that 
a cubic foot of soil high in organic con¬ 
tent can hold twice as much water as a 
cubic foot of sand. 
In crop production, there is a close and 
very important relation between the flora 
of the soil and chemical changes that take 
place in same. Right here I should like 
to say, it is my humble opinion that the 
solution of some of our big problems in 
citrus fruit production will be solved only 
through a more extensive knowledge of 
the flora of the soil and its relation to 
higher plant growth. It is interesting to 
note here that we must depend largely 
upon the action of bacteria to bring about 
decay of organic matter and to make 
chemical changes necessary to plant 
growth, and that these bacteria as well as 
other necessary soil organisms derive their 
source of energy from the organic matter 
of the soil. A rich bacterial flora, there¬ 
fore, depends upon an adequate supply of 
organic matter in the soil. When a citrus 
soil becomes deficient in organic matter 
the action of necessary soil organisms is 
greatly impaired, resulting in poor crops 
and often diseased trees. 
A large percentage of our plant food 
comes from organic sources and depends 
upon the action of bacteria to render the 
plant food therein available to plants. 
The plant food in all animal and vegetable 
matter, such as bone, tankage, guano, cot¬ 
ton-seed meal, tobacco stems, etc., must 
undergo decay through certain micro-or¬ 
ganisms before it can be used by the or¬ 
ange tree. The organic nitrogen must be 
converted by the action of ammonifying 
and nitrifying bacteria before it is avail¬ 
able to the plant. Keep in mind that these 
bacteria depend upon the organic matter 
of the soil for their energy. Organic mat¬ 
ter of the soil also has a beneficial effect 
upon the inorganic constituents of our 
fertilizers. Organic acid compounds 
formed by the decomposition of organic 
matter change insoluble potassium and 
phosphorus compounds into soluble form. 
Carbon dioxide, which comes from de¬ 
composition of organic matter, increases 
the solvent power of soil water on phos- 
