15 



The graphs representing active versus inactive organic nitrogen show that the 

 activity of the water insoluble nitrogen improves as the ammonia guarantee is in- 

 creased. The slightly lower activity of the total organic nitrogen in case of those 

 brands with an ammonia guarantee of 5 per cent or over is due no doubt to the pres- 

 ence of organic vegetable ammoniates such as cottonseed meal, castor pomace, etc., 

 foimd in the brands for tobacco. The alkaline permanganate method is not as well 

 suited for this class of materials as is the neutral method, which places them among 

 the high grade products where they belong. 



The following table lists those brands which were found during the 1923 inspection 

 to have their water insoluble nitrogen in forms testing under 50 by the alkaline and 

 under 80 by the neutral permanganate methods, and which did not show a sufficient 

 overrun of total nitrogen so that the minimum guarantee was met by the more active 

 forms. 



Note. — The pulverized manures and Alphano Humus are not listed in the table. These products invariably 

 show a low activity of their water insoluble organic nitrogen. 



Percentage, Character and Cost of Plant Food. 



The average composition of mixed fertilizers and the cost of plant food in high- 

 analysis versus low-analysis mixtures are shown in the following tables : — ■ 



Note. — Of the total number of brands analyzed, 17 per cent failed to meet the minimum guarantee of nitro- 

 gen; 15 per cent, the minimum guarantee of available phosphoric acid; 22 per cent, the minimum guarantee 

 of potash. Forty-two brands of tobacco fertilizer showed an average of .17 per cent of chlorine, equivalent to .36 

 per cent of muriate of potash. 



