31 



lively low nitrogen activity by the vegetation experiment, the average 

 of sixteen such cases being 46.5 by the alkaline permanganate method 

 and 32 by the vegetation experiment. It should be noted in this 

 connection that the laboratory method favors the fertilizer in almost 

 every instance. 



3. Sample No. 11 was the only complete fertilizer tested which 

 shows the water insoluble organic nitrogen to be of good quality when 

 measured by the vegetation experiment and of suspicious quality 

 by the laboratory method. A large proportion of the organic nitro- 

 gen in this brand was derived from cottonseed meal and castor pom- 

 ace. The results obtained with castor pomace also show that the 

 laboratory method is likely to give somewhat too low results on this 

 class of organic ammoniates. This bears out the observations of 

 Jones of Vermont and Hartwell of Rhode Island, and suggests that on 

 such brands, in the future, some other method should be used such 

 as the acid pepsin digestion method. 



It must be remembered that the above data are the result of only 

 one year's experiment. They indicate, however, in most cases that 

 the alkaline permanganate method is of distinct value in separating 

 the good from the inferior forms of organic nitrogen. The ease and 

 rapidity with which the method can be executed warrants a con- 

 tinuance of its use in our inspection work. 



It may be of interest to note that at a recent meeting of the Asso- 

 ciation of Official Agricultural Chemists both the alkaline perman- 

 ganate method and the neutral permanganate method were made 

 official. 



Eighty-four per cent of the total phosphoric acid found 



Character of in all the complete fertilizers analyzed was present in 



Phosphoric available form and 55 per cent of the available phos- 



Acid. phoric acid was present in water soluble form. This 



shows a greater solubility than occured during the 

 previous year. In case of the superphosphates or acid phosphate 95 

 per cent of the average total phosphoric acid found was classed as 

 available and 74 per cent of the available phosphoric acid was in 

 water soluble form. This shows the use of materials other than 

 superphosphates or acidulated goods in the make-up of the complete 

 fertilizers. Of course this is a legitimate practice as the use of dif- 

 ferent grades of tankage necessitates the presence of more or less 

 phosphoric acid in the tricalcic form. 



In the tables of analyses wherever the potash is pres- 



Character ent in form of sulfate or carbonate an asterisk (*) 



of or dagger (f) has been used in the "found" potash 



Potash. column. These characters refer to foot notes giving 



the proportion of each form of potash. The absence 



of these characters indicates that all the potash present is as chloride. 



