60 
being formed. 1 By making the material more compact, this will 
tend to conserve ammonia. 
Low-grade phosphatic guanos can be mixed with coffee hulls and 
pulp, which contain a small amount of potash. Doubtless the acetic 
acid produced in the fermented hulls and pulp will aid somewhat in 
rendering the phosphates more available. Experiments, however, 
have not been conducted in support of this conclusion. Composting 
insoluble phosphatic guanos with waste or decaying citrus fruits and 
pineapples or with refuse from pineapple canneries would doubtless 
be quite effective in increasing the availability of the phosphoric acid 
in such materials. 
APPLICATION OF GUANOS. 
In applying the guanos it should be borne in mind that most of 
them contain little water-soluble material. Consequently they will 
be most effective when well and evenly mixed with the soil. 
When fresh bat manure or guanos high in nitrogen and organic 
matter are to be used for young pineapples, the material may be 
safely applied in the crown, as is done with dried blood. Even 
though these guanos should contain considerable ammonia and nitrate 
there will be little danger of injuring the plants, as the bulky nature 
of the fertilizer prevents dangerous concentration of soluble salts in 
any place. Only fresh bat manures or guanos composed chiefly of 
organic matter should be applied in this way, as other guanos, like 
soil, will tend to smother the plant. 
CROPS ON WHICH GUANOS CAN BE USED. 
Compounded with other materials, on the basis of their analysis 
and efficiency, to make the proper formula, guanos can be used for 
any crop. There are some specific features about the guanos, how- 
ever, which make them especially good for long-time crops. 
In the previous pages it was shown that the phosphoric acid in 
guanos lost less in availability by remaining in the soil than that in 
acid phosphate. Consequently when used in mixtures for citrus 
trees, pineapples, sugar cane, yams, coconuts, and other crops of a 
long growing season, many guanos will show a greater efficiency rela- 
tive to acid phosphate than they will for quick crops like lettuce, 
radishes, etc. This does not mean that guanos are not effective for 
quick crops. If used on the basis of the immediate efficiencies indi- 
cated in the previous pages, they will be equally as effective as the 
standard fertilizers. 
All the guanos contain a considerable portion of their nitrogen in 
an insoluble and relatively unavailable form. To this part of the 
1 Mixing insoluble phosphates with stable manure has been advocated as tending to increase the availa- 
bility of the phosphoric acid, but there is some question as to whether any decided increase in availability 
results from this treatment. 
