178 STATE BOARD OF AGRICULTURE. 



The conductivity method does give a strictly neutral solution and 

 the authors believe it should be adopted as one of the oflScial methods 

 for determining the neutral point of ammonium citrate solutions. 



THE USE OF BUSCH'S "NITRON" FOR THE DETERMINATION OF NITRATE 

 NI^l^ROGEN IN SOILS AND FERTILIZERS. 



BY C. S, ROBINSON AND O. B. WINTER. 



The object of the work reported in this article is the comparison of 

 the official zinc-iron reduction method for the estimation of nitrate 

 nitrogen with the so-called "Nitron" Method of Busch, as applied to 

 soils and fertilizers. In the course of the work now being done in this 

 lab(h*atory, on the nitrogenous compounds of humus, it became neces- 

 sary to run a considerable number of nitrate determinations on soils 

 rather rich in organic matter. It was thought that under the influence 

 of the strong reducing agents used in the official method some of the 

 organic nitrogenous ccmipounds might be broken down with the forma- 

 tion of ammonia, thus, causing high results. We hoped to adopt some 

 modification of the ''Nitron" method to the work and eliminate this 

 source of error. The results were, however, not at all satisfactory. In 

 a few cases on oi-diuary soils good results were obtained but if any 

 considerable amount of organic matter was present, the precipitate, if 

 at all crystalliu was dark colored, and in many cases only brown 

 flocculent material was thrown down. 



This was not true in the ca.'^e of commercial fertilizers as was antici- 

 pated from the fact that several articles,^ have recently appeared, report 

 ing good success with the use of "Nitron" for the determination of nitric 

 nitrogen in commercial nitrates. Occassionally bi'ands of commercial 

 fertilizers are encountered with which it is difficult to get consistent 

 results using tlie official metliod for nitrates and it is highly desirable 

 that some new method, applicable to such cases be developed. A num- 

 ber of comparative analyses were made by the two methods on brands 

 giving good results with the official method to see if equally good re- 

 sults could not be obtained with the "Nitron" method. The results were 

 very satisfactory and it seems proba1)le that the "Nitron" method could 

 be used to advantage in the analysis of such material. 



ACCURACY OP THE METHOD. 



Jiusch claims that ''Nitron" or 1.4-diphenyl-3.5 endanilodihydrotryazol 

 will preci])itate nitric acid from solutions of one in sixty thousand at 

 ordinary temperatures and one in eighty thousand at zero degrees. This 



iL. Radlborger, Oslcir. Tiugar. Ztschor. Zuckeriudiis. ii. Laudw. 39, 433 (Abs. in E. S. 

 R. Ii4, lUU). 



A. M. WasUiefr, Zliiir. Rubs. Flz. Khim. Obsch. Chnst Khim 42, 567, (Abs. in E. S. R. 

 24. 600). 



