CONTROL SERIES No. 100 



Summary of Deficiencies in Mixed Fertilizer 



Of the 327 brands analyzed, 165, or 50 per cent, showed no deficiencies. Out 

 of 1,003 plant food guarantees made, 79 per cent were fully maintained. 

 The deficiency table shows the following statistics: 



Deficiencies not exceeding x /i of one per cent, 138. 

 Deficiencies between J4 and Yi of one per cent, 48. 

 Deficiencies between H and % of one per cent, 14. 

 Deficiencies more than % OI one P er cent, 11. 



Of the total number of guarantees of each element made, 31 per cent of the 

 nitrogen, 13 per cent of the available phosphoric acid, and 21 per cent of the 

 potash were not met. Sixty-three of the 101 nitrogen deficiencies, 23 of the 41 

 available phosphoric acid deficiencies, and 49 of the 67 potash deficiencies did 

 not exceed }4 of one per cent. 



Compared with the 1938 inspection, there were 66 more shortages in nitrogen, 

 29 less in available phosphoric acid, and 35 more in potash. 



In the case of those fertilizers which did not conform strictly to the guarantee, 

 the discrepancies were of such a character as to make it evident that there was no 

 intentional attempt at violation of the regulations. 



Fifteen 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 follow- 

 ing table shows to what extent each manufacturer was successful in avoiding 

 deficiencies in plant food guarantees in his mixtures. Nine of the fifteen firms 

 provided an average overrun in the three major plant food elements guaranteed, 

 considered desirable in safe fertilizer practice. 



