27 



Mixed Commercial Fertilizers showing Inferior Forms of Organic 

 Nitrogen (Per Cent). 



Phosphoric Acid in Mixed Fertilizers. — Of the total phosphoric acid 

 found in the complete mixed fertilizers, 85.5 per cent was present in available 

 form, and 66.4 per cent of the available phosphoric acid was in water soluble 

 form. In case of the ammoniated superphosphates, 87.9 per cent of the total 

 phosphoric acid was in available form, and 61.2 per cent of the available 

 phosphoric acid was in water soluble form. These figures indicate that a 

 somewhat higher proportion of acid was used in the manufacture of the 

 superphosphates which entered into the mixture than during the previous 

 year. This resulted in a higher availability of the phosphoric acid present. 



Potash in Complete Fertilizers. — The average complete fertilizer con- 

 tained 1.88 per cent of water soluble potash. As a whole, potash was used 

 somewhat more freely in the mixtures than during the previous year. Sixty- 

 seven brands had but 1 per cent of potash guaranteed, 20 had 2 per cent, 10 

 had 3 per cent, and 13 had a minimum of 4 per cent guaranteed. Out of a 

 total of 119 brands analyzed, 47, or 39.5 per cent of the total number, failed 

 to m^eet the minimum potash guarantee. There is evidence that most of the 

 potash supplied in mixed fertilizers was from American produced potash 

 salts, as most mixtures contained both soluble chlorides and sulfates in about 

 the same proportion as during the previous year. As a whole, there was not 

 a sufficient amount of chlorine present to prove harmful even to fertilizers 

 manufactured for tobacco. The large number of potash deficiencies is un- 

 fortunate and indicates that the manufacturer failed in most instances to 

 make a sufficient allowance for variation in the composition of the products. 



