11 



Average Proportion and Quality of the Different Forms of Nitrogen found 



in Mixed Fertilizers. 



A comparison of the data contained in the above table with similar data for 1924 

 shows that more mineral nitrogen was used in 1925 in grades having up to 4 per 

 cent minimum ammonia guarantee (3.29 per cent nitrogen), the same holding true 

 on those brands having an ammonia guarantee of over 7 per cent. In those grades 

 having an ammonia guarantee between 4 per cent and 7 per cent, less mineral and 

 more organic nitrogen was used than in 1924. 



The percentage activity of the water insoluble nitrogen was on the average much 

 more satisfactory than in 1924, although a larger number of brands showed the 

 presence of inferior forms of organic nitrogen than for several years. This ap- 

 parently contradictory assertion is explained by the fact that the activity of the 

 insoluble nitrogen on those brands showing satisfactory tests was on the average 

 higher than for 1924. 



Fertilizer Brands Showing Inferior Insoluble Organic Nitrogen. 



1 One other analysis (two samples) of this brand showed a satisfactory activity of the water insoluble 

 nitrogen. 



2 Two analyses, four samples. 



' Two analyses, eight samples. One other sample showed only .3 per cent of insoluble nitrogen, which 

 was considered too small for an activity test. 



< One analysis, three samples. Two other analyses, eight samples, although showing a low activity of the 

 water insoluble nitrogen, were passed as they showed a sufficient overrun so that the minimum guarantee 

 was met by the sum of the more active forms of nitrogen. 



* One analysis, five samples. One other analysis, two samples, showed an activity of .52% by the alkaline 

 permanganate method. One other analysis, two samples, showing a low activity was passed, the minimum 

 guarantee having been met by the more active lorms of nitrogen. 



^ One analysis, one sample. One other analysis, two samples, showed an activity of 50% by the alkaline 

 permanganate method. One other analysis, two samples, was passed, the nainimum guarantee having 

 been met by the more active forms of nitrogen. 



