12 

 Average Proportion and Quality of the Different Forms of Nitrogen found in 



Mixed Fertilizers. 



The relativ^ely high proportion of water soluble organic nitrogen in the 

 grades having an ammonia guarantee up to 3 per cent indicates that the 

 organic nitrogen may be derived largely from base goods (processed organic 

 materials). In these brands the water soluble nitrogen is relatively high 

 (about 72 per cent of the total nitrogen), thus likely insuring a quicker action 

 than would be the case if the organic nitrogen were derived largely from tank- 

 age or other uncooked, unacidulated organic material. 



A comparison of the above figures with similar data secured for the previous 

 year shows that more mineral nitrogen was used in 1924; that the percentage 

 activity of the total nitrogen and of the organic nitrogen was about the same, 

 while the percentage activity of the insoluble nitrogen showed a small im- 

 provement in 1924, particularly in the higher ammonia guarantees. The 

 high percentage activity of the total organic nitrogen in brands with the smaller 

 ammonia guarantees is explained by the presence of the higher water soluble 

 organic nitrogen, all of which is considered to be in active form. The percent- 

 age activity of the water insoluble nitrogen seems to increase with the total 

 ammonia guarantee, which indicates the use of high-grade, unprocessed organic 

 ammoniates and a correspondingly smaller proportion of base mixture in 

 supplying the organic portion of the total ammonia guarantee. 



The table, as a whole, shows that the Massachusetts farmer has but little 

 complaint as to the average quality of the organic nitrogen furnished in the 

 mixed commercial fertilizers sold in the state. 



Inferior Forms of Organic Nitrogen 



No extensive criticism can be made regarding the quality of the organic 

 nitrogen used in mixed fertilizers in Massachusetts during the season. There 

 is some evidence that the water insoluble nitrogen found in certain base goods 

 mixtures is of rather low activity. The brands in question have been passed 

 in the bulletin without unfavorable criticism, yet many vegetation tests made 

 on water insoluble residues of base goods mixtures testing just over the passing 

 mark (50 per cent activity by alkaline permanganate method) indicate that 

 the insoluble nitrogen should not be classed as high as when derived from 

 animal tankage, fish, and other highly active organic ammoniates. It is 

 hoped that an improvement will be made another season by the manufacturer, 

 either in using a base goods of higher insoluble nitrogen activity, or in being 

 more liberal in the quantity of nitrogen furnished in the mixtures, in order 

 that a sufficient overrun may furnish the minimum nitrogen guarantee in 

 freely active forms. 



Only two brands of mixed fertilizers were found on which the water insoluble 

 nitrogen tested under 50 by the alkaline, and under 80 by the neutral, perman- 

 ganate methods, and which did not have a sufficient excess of nitrogen so that 

 the minimum guarantee was met by the more active forms. 



