THE PRINCIPLES OF FERTILIZER PRACTICE 481 



for the purpose, in order to ascertain whether the mixture is 

 up to guarantee. The expense of the inspection and control of 

 fertilizers is usually defrayed by the license fee or the ton- 

 nage tax. 



If the fertilizer falls below the guarantee, — allowing, of 

 course, for the variation permitted by law, — the manufacturer 

 is subject to prosecution in the state courts. A more effective 

 check on fraudulent guarantees, however, is found in pub- 

 licity. The state law usually provides for the publication 

 each year of the guaranteed and found analyses of all brands 

 inspected. Not only has this proved effective in preventing 

 fraud, but it is really a great advantage to the honest manu- 

 facturer, as his guarantees receive an official sanction. The 

 found analysis of most fertilizers is generally above the 

 guarantee. 



271. The fertilizer guarantee. — Every fertilizing mate- 

 rial, whether it is a single carrier or a complete ready -to-apply 

 mixture, must carry a guarantee. The exact form is gener- 

 ally determined by the state in which the fertilizer is offered 

 for sale. The content of nitrogen is almost invariably ex- 

 pressed in terms of ammonia (NH 3 ), although the amount of 

 total nitrogen is sometimes required in addition. The phos- 

 phorus is quoted in terms of phosphoric acid (P 2 5 ). In 

 some cases, a bone-phosphate of lime (B. P. L. or Ca 3 (P0 4 ) 2 ) 

 equivalent is included. The guarantee of a simple fertilizer 

 material is easy to interpret, since the name of the material is 

 printed on the bag or tag. When the amount of the nutrient 

 element carried is noted, the availability and general value 

 of the goods is immediately known. If the material is sodium 

 nitrate at 18 per cent, ammonia, it is apparent that the fer- 

 tilizer is high-grade and should give immediate and definite 

 results when properly applied to a growing crop. 



The interpretation of a complete fertilizer analysis is not 

 as easy, however, since the names of the carriers are seldom 

 included in the guarantees. The simplest form of guarantee 



