UNIVERSITY OF CALIFORNIA PUBLICATIONS 



IN 



AGRICULTURAL SCIENCES 



Vol. 1, No. 4, pp. 51-62 May 15, 1913 



THE ALUMINUM REDUCTION METHOD AS /*^^ vo^ 

 APPLIED TO THE DETERMINATION OF «^<io^, 



NITRATES IN "ALKALI" SOILS 



BY 

 PAUL S. BURGESS 



While the phenoldisiilphonic acid method for determining 

 nitrates in soils at present offers the most speedy and satisfactory 

 means of ascertaining the nitrate content of soils free from 

 "alkali," it has been shown^ to be of questionable value when 

 employed with soils containing even small amounts of soluble 

 salts, and especially in the presence of the chlorides and sulfates 

 of the alkalies. Since this is true, and further since the number 

 of nitrate determinations on soils containing "alkali" is con- 

 stantly increasing, due to the great increase in our research work 

 on "alkali" problems, both chemical and bacteriological, it was 

 deemed by the Avriter to be a matter of importance to establish 

 a method for the determination of nitrates which was not affected 

 by the presence of soluble salts. 



The possible methods considered were Busch's "nitron" pro- 

 cess, the methods depending upon the liberation and subsequent 

 measuring of nitric oxide, and the reduction methods in which 

 the nitrate nitrogen is reduced to ammonia and either titrated 

 against a standard acid solution or Nesslerized. 



Busch's "nitron" process- was rejected for the following 

 reasons. A number of the acids (both organic and inorganic), 



1 Univ. of Calif. Publ. Agr. Sci., vol. 1, no. 2, pp. 21-37. Utah Agr. 

 Exp. Sta. Bull., 106. 



2 Ber. Dent. Chem. Gsell. 38 (1905), 3, pp. 861-866. 



