10 



The above tables show a marked improvement in 1923 over former years, in the 

 maintenance of the guarantees on mixed fertiHzers. They indicate effort on the part 

 of manufacturers to so organize their forces as to reduce to the minimum accidental 

 variation in the composition of fertilizers. It is hoped that the present standard of 

 efficiency may be maintained. 



Mixing Efficiency. 



The following table has been prepared to show to what extent the various com- 

 panies have been successful in making their mixtures conform to the minimum guar- 

 antees. It is based upon the percentage of plant food guaranteed by the several 

 companies, on the statements of tonnage data rendered by these companies, and on 

 the results of experunent station sampling and analysis. Manufacturers included in 

 this table are confined to those having four or more brands registered, sampled and 

 analyzed. 



The above table shows that of the 29 manufacturers, — 



21 showed an overrun in all of the elements guaranteed. 



25 showed an overrun and 4 a shortage in nitrogen. 



28 showed an overrun and 1 a shortage in available phosphoric acid. 



26 showed an overrun and 3 a shortage in potash. 



The data indicate that in most instances, particularly among the larger companies, 

 provision is made for a suitable margin of overruns. In case of some of the smaller 

 manufacturers more attention might be profitably given to the chemical composition 

 of the crude stock materials which make up the fertilizer formula. 



