CONTROL SERIES No. 105 



Serious Commercial Shortages in Mixed Fertilizers. 



Of thp 295 brands analyzed, 12S, or 43 percent, showed no deficiencies. 

 of 895 plant food guarantees made, 75 percent were fully maintained. 

 The deficiency table shows the following statistics : 



Out 



Deficiencies not exceeding }/i of one percent, 129. 

 Deficiencies between 34 and Yi of one percent, 45. 

 Deficiencies between H and % of one percent, 27. 

 Deficiencies more than % of one percent, 19. 



Sixteen firms have registered five or more brands of mixed fertilizers. On the 

 basis of composition found by analysis as well as of tonnage sold, the following 

 table shows to what extent each manufacturer was successful in avoiding defi- 

 ciencies in plant food guarantees in his mixtures. Seven of the sixteen firms have 

 an average deficiency in one or more plant food elements. The average percentage 

 of total plant food of three of these firms is below the minimum guaranteed. This 

 is a very unsatisfactory showing. In order to have reasonable assurance that his 

 mixtures will conform to the guaranteed analysis, the manufacturer should allow 

 as a minimum an average overrun of one-tenth of one per cent for each element. 



Average Deviation from Guaranteed Analysis 



