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CONTROL SERIES No. 90 



Summary of Deficiencies in Mixed Fertilizers 



Serious Commercial Shortages in Mixed Fertilizers 



Of the 296 brands analyzed, 202, or 68 percent, showed no deficiencies. Out 

 of 910 plant food guarantees made, 87 percent were fully maintained. 

 The deficiency table shows the following statistics: 

 Deficiencies not exceeding )/i of one percent, 74. 

 Deficiencies between 3^ and J^ of one percent, 28. 

 Deficiencies between Yi and % of one percent, 3. 

 Deficiencies more than % of one percent, 10. 

 Of the total number of guarantees of each element made, 13 percent of the 

 nitrogen, 10 percent of the available phosphoric acid, and 16 percent of the 

 potash were not met. Twenty-five of the 39 nitrogen deficiencies, 19 of the 

 29 available phosphoric acid deficiencies, and 30 of the 47 potash deficiencies 

 did not exceed 3^ of one percent. 



Compared with the 1936 inspection, there were 17 more shortages in ni- 

 trogen, 4 less in available phosphoric acid, and 21 more in potash. 



In the case of those fertilizers which did not conform strictly to the guar- 

 antee, the discrepancies were of such a character as to make it evident that 

 there was no intentional attempt at violation of the regulations. 



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

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

 following table shows to what extent each manufacturer was successful in 

 avoiding deficiencies in plant food guarantees in his mixtures. All but three 

 of the twelve firms provided an average overrun in the three major plant food 

 elements guaranteed, considered desirable in safe fertilizer practice. 



