11 



Nitrogen in Mixed Fertilizers. 



An average of all of the mixed complete fertilizers analyzed shows total nitrogen, 

 3.66 per cent; consisting of nitrogen in mineral forms, 2.25 per cent; and in organic 

 forms, 1.41 per cent. The totaliiitrogen had an activity of 79 per cent, and the 

 water insoluble nitrogen, an activity of 65 per cent, determined largely by the 

 alkaline permanganate method. 



Average Proportion and Quality of the Different Forms of Nitrogen found 



in Mixed Fertilizers. 



Sixteen per cent more mineral nitrogen was used than in 1925 in those fertilizers 

 having less than 2 per cent ammonia guarantee. This is a decided improvement, 

 in so far as these low ammonia mixtures are, or should be, used largely as supple- 

 ments to the farm manurial supply. An increased proportion of mineral nitrogen 

 was also used in those brands having an ammonia guarantee between 4 and 7 

 per cent. Grades having ammonia guarantees between 2 and 4 per cent and over 

 7 per cent showed somewhat less mineral nitrogen than in 1925. 



The percentage activity of the water insoluble nitrogen was somewhat higher 

 than in 1925 in grades with less than 2 per cent and over 6 per cent ammonia 

 guaranteed. On all other grades the percentage activity was somewhat, but not 

 significantly, less. 



Fertilizer Brands Showing Inferior Insoluble Organic Nitrogen. 



' Three analyses. 



2 One other analysis showed a satisfactory activity of the water insoluble nitrogen. 

 ' Three analyses. 



* Six other samples, two analyses, were passed, the guarantee of nitrogen having been met by the more 

 active forms of nitrogen. 



