FERTILIZERS

271

It is therefore a matter of great importance to the analyst that
he should know the origin of the constituents of a fertilizer
because the methods of analysis and the interpretation of results
differ according to the nature of the material present.

The composition of some of the more common fertilizers is
indicated in the following table:

TABLE XXIII.—APPROXIMATE COMPOSITION OF CERTAIN COMMERCIAL
SAMPLES OF FERTILIZERS WITH RESPECT TO THREE ESSENTIAL

ELEMENTS

Name of material

Fresh farm manure.............

Dried blood....................

Sodium nitrate (com.)...........

Ammonium nitrate (com.).......

Acid phosphate (com.)..........

Acidulated bone meal...........

Steamed bone meal............

Raw bone meal................

Raw rock phosphate...........

Basic slag.....................

Potassium sulphate (com.).......

Potassium chloride (com.)......

Wood ashes...................

Pounds of element per ton of
fertilizer

Nitrogen | Phosphorus I Potassium

10
280
310
400

40
20
80

125
140
250
180
250
160

10

850
850
100

Ill

Compatibility.—When artificial manures are to be mixed it is
important to know what ones can be combined without loss of
fertilizing value. Losses may be caused by reactions that release
combined nitrogen, usually in the form of ammonia, or that
make a phosphate less available to the plant by producing less
soluble compounds.
When an acid phosphate, for example, is mixed with sodium
nitrate or calcium nitrate free nitric acid is produced and this may
be partly lost:
Ca(H2P04)2 + 4NaN03 -» CaNaP04 + Na8PO4 + 4HNO3.