OFFICIAI, INSPECTIONS 42. I27 



AvAiivABLE Nitrogen. 



The availability of mineral nitrogen is well known and also 

 that of the best forms of organic nitrogen. With the great 

 increase in demand and consequent increase in price, and in 

 accord with the modern idea of conservation, it has been neces- 

 sary to press into use all obtainable forms of organic nitrogen. 

 Under existing conditions if no examination of the quality of 

 the organic nitrogen were made there would be a chance that 

 low grade materials might be rated as high grade with a con- 

 sequent injustice to both the consumer and honest manufac- 

 turer. Nitrogen from such sources as garbage tankage, leather 

 waste, hair, etc., is usually of low availability and only slowly 

 taken up by the plant. 



For several years chemists have recognized this condition 

 and many attempts have been made to devise practical labora- 

 tory methods for determining the quality of the nitrogen in 

 mixed goods. Some of these methods while fairly accurate are 

 too time consuming to admit of their use in inspection work. 

 The method which seems to promise to be quite satisfactory is 

 the so-called alkalin permanganate method which was suggested 

 from the use of this chemical to determine albuminoid nitrogen 

 in water analyses. As far back as 1893-4 some work was done 

 with permanganate of potash in this laboratory in an attempt 

 to use it to determine whether leather waste was being used 

 in some fertilizers. Later Mr. S. H. T. Hayes, a former as- 

 sistant in this Station, worked out the method while a post- 

 graduate student at Cornell University. Mr. Hayes' paper was 

 published in Bulletin 47 of the Bureau of Chemistry, U. S. 

 Department of Agriculture, in which is given both the alkaline 

 and acid permanganate methods. Since that time a few ex- 

 periment stations have continued investigations in this line. 



At a meeting of the directors of the New England States, 

 New York and New Jersey, held in Boston in March 1910, the 

 whole question of the quality of the organic nitrogen in com- 

 mercial fertilizers was thoroughly discussed and the urgent 

 need of an adequate discriminatory method was generally recog- 

 nized. A committee was appointed, consisting of the chemists 

 of the Vermont, Connecticut (State) and Rhode Island Sta- 

 tions to further investigate the applicability of chemical meth- 

 ods to the determination of availability of organic nitrogen 



