Official Inspections 97. 69 



The organic nitrogen may be natural by-products such as 

 animal and vegetable wastes or artificial organic forms. Cyan- 

 amide nitrogen is about the only artificial organic form occurr- 

 ing in fertilizers and that is used very sparingly by manufac- 

 turers. The nitrate nitrogen, ammonia nitrogen, cyanamide 

 nitrogen, and part of the other organic nitrogen is water sol- 

 uble. The organic nitrogen (other than cyanamide nitrogen) 

 will differ greatly in its availability due to its source. By care- 

 ful and painstaking pot experiments the availability of most 

 common forms of waste organic nitrogen have been ascertained 

 and a laboratory method has been worked out that agrees reas- 

 onably well with the vegetative trials. So that the Experiment 

 Stations of the Northeastern part of the United States have 

 agreed upon a chemical mehod which gives an index to the 

 character of the waste organic nitrogen used in making fertili- 

 zers. Some manufacturers of fertilizers use a wet process 

 treatment of these low grade waste organic nitrogen materials 

 whereby they are rendered far more available to plants than 

 before being treated. This treated material has been tested out 

 in vegetative experiments and the laboratory method has also 

 been found to give a reasonable measure of the availability of 

 this nitrogen. The column headed Active gives the total of 

 the water soluble nitrogen and the waste organic nitrogen that 

 can be counted upon as available to plants the first season the 

 goods are applied. The active nitrogen bears some such rela- 

 tion to the total nitrogen as available phosphoric acid bears to 

 total phosphoric acid. Under the Maine law the nitrogen is 

 supposed to be guaranteed as "available nitrogen" but as will 

 be noted from the table in most cases this agrees much more 

 closely with the total than with the active nitrogen that the goods 

 carry. 



That there is of necessity no close relation between the 

 total and the active nitrogen is illustrated by B-i and B-2 above. 

 The total nitrogen found in B-i is 3.63 per cent and in B-2 

 only 2.85 per cent. But the active nitrogen is practically the 

 same in both (B-i 2.76 per cent and B-2 2.72 per cent). 



From the data given in the table all of the forms of nitro- 

 gen that the goods may carry with the exception of cyanamide 

 nitrogen can be obtained. If, for instance, it is desired to know 

 the percentage of organic nitrogen carried by any sample it 



