10 
BULLETIN 1280, U. S. DEPARTMENT OF AGRICULTURE 
Among the concentrated materials listed in Table 3 are the salts, 
monoammonium phosphate, monopotassium phosphate, and potas- 
sium nitrate. These compounds contain combinations of all three 
fertilizer constituents in groups of two, and all have chemical and 
physical properties which make them admirably suited for use in 
fertilizers. Potassium nitrate has long been used to a limited extent 
in fertilizers, and is obtained from Chilean nitrate and other sources. 
It may also be prepared by treating potassium chloride with nitric 
acid such as that produced in the fixation of nitrogen. Monoammo- 
nium phosphate is now being used to some extent in high-grade fer- 
tilizers, and may be prepared by neutralizing ammonia, such as 
obtained in the fixation of nitrogen, with phosphoric acid. The use 
of monopotassium phosphate in fertilizers has been limited to experi- 
mental tests only. It may be prepared from potassium chloride and 
phosphoric acid. The percentage composition of these salts is given 
in Table 4. 
Table 4. — Composition of concentrated fertilizer salts 
Composition on basis of— 
Salt 
Total material ! Fertilizing elements present 
NH 3 
P2O5 
K 2 j NH3 
P2O5 1 K2O 
1 
Per cent 
14.80 
Per cent 
61.72 
52.18 
1 
Per cent Per cent 
19. 34 
Per cent 
80.66 
60.14 
Per cent 
Monopotassium phosphate, K H2PO4 . 
34.59 < 
39.86 
Potassium nitrate, KNO3... . . 
16.85 
46.58 : 26.57 
74.43 
FERTILIZER MIXTURES FROM CONCENTRATED MATERIALS 
Applying the triangular system to fertilizer mixtures from con- 
centrated materials, it is seen from the percentage values given in 
Table 4 that monoammonium phosphate corresponds to the point 
D in the triangle of Plate II; monopotassium phosphate to the point 
E and potassium nitrate to the point F. These three materials may 
therefore be used to make submultiples of all fertilizer ratios falling 
within the triangle DEF. In the same way, triangles may be drawn 
corresponding to combinations of any two of these compounds with a 
nitrogen, phosphoric acid, or potash salt. Thus the triangle ABE 
incloses all possible ratios that can be made with mixtures of mono- 
ammonium phosphate, monopotassium phosphate, and a nitrogen 
compound; the triangle CDE all ratios that can be prepared from the 
same two compounds and a potash salt, and the triangle BDE all 
the ratios that can be made from these two compounds and a phos- 
phatic material, such as acid phosphate. 
When each of three materials selected for a mixture contains two 
fertilizing elements, then the amount of each required to give a ton 
of a fertilizer of any anatysis formula which they are capable of 
making, as shown by the triangle method, may be calculated as 
follows : 
If A, B, and C are the percentages respectively of the NH 9) P 2 5 , 
and K 2 desired in the mixed fertilizer, and — 
X = Weight of material containing a per cent NH 3 , and b per cent 
PA. 
