762 EXPERIMENT STATION RECORD. 



that takiug water-soluble phosphoric acid as 100, the effectiveness of 

 the phosphoric acid in the peat and excrement mixture was 90.9 and in 

 the poudrette 56.8. Analyses of the plants showed that if the amount 

 of phosphoric acid assimilated in case of the soluble phosphoric acid 

 be taken as 100, the amount assimilated iu case of the mixture was 

 96.2 and iu case of the poudrette 44.8. There was little difference in 

 the fertilizing effect of nitrogen of the two kinds of manures. Taking 

 nitrogen of nitrate of soda as 100, the effectiveness of the nitrogen of 

 the mixture, in the light application was 62.2, in the heavy application 

 49.1 ; poudrette in the liglit application 5 t.l, in the heavy application 49. 

 The after effect of the nitrogen was quite marked, and very nearly the 

 same in each case. 



Perchlorate as a cause of the injurious effect of nitrate of soda 

 on rye, B. S.tollema {Chem. ZUj., 20 {1896), iV"o. 101, j)}). 1002, 1003).— 

 The injurious effect of nitrate of soda has been noted by a number of 

 observers' and several explanations of it have been suggested, among 

 others, that the injury was due to a deficiency of rainfall resulting in 

 the soil solution of nitrate becoming too concentrated. The author 

 observed, however, that of parallel plats of rye receiving different kinds 

 of nitrate of soda some were seriously injured while others were not so 

 affected, indicating that the injury was due to some constituent of the 

 nitrate itself. A chemical examination of samples of nitrate which 

 had been found to be very injurious to rye revealed the presence of 

 considerable percentages of perchlorate, ranging from 0.94 to 6.79 per 

 cent. 



For the determination of perchlorates 100 gm. of the nitrate was dis- 

 solved in 500 cc. of water. In 50 cc. of this solution chlorin was 

 directly determined by titration with silver solution, and a second aliquot 

 of 50 cc. was evaporated to dryness, carefully ignited, dissolved iu 

 water, and the chlorin determined as in the first. The difference 

 between the first and second determinations was taken to represent 

 the chlorin due to perchlorates. Tests of the method on pure salts indi- 

 cated that it gave quite accurate results, although there was danger of 

 error due to volatilization of chlorin. 



The results of analyses indicate that the jierchlorate is in the form of 

 potassium perchlorate. Tests of the effect of potassium and sodium 

 perchlorate on the germination and upon the young i)lantlets of rye 

 are also reported. The number of seeds germinating was not affected, 

 but the growth of the plantlets was retarded and frequently altogether 

 checked by small i)ercentages of perchlorate. A one-half per ceut 

 solution was sufficiently strong to bring about this result. Pure nitrate 

 also checked growth, but to a much less extent. 



Pot experiments are reported, in which different amounts of potassium 

 and sodium perchlorate, mixtures of sodium nitrate and i^otassium per- 

 chlorate, and pure sodium nitrate and commercial sodium nitrate con- 

 taining perchlorates were applied to rye. The injurious effect of the 



1 A. Stutzer, Den*, landw. Presse, 23 (1896), No. 66. p. 592 (E. S. K., 8, p. 391). 



