No. 4.] MANURIAL PROBLEMS. 147 



Concerning the Manurial Value of Sodium. 

 Since the presentation of the former pai)er before your 

 Board, flordan and flentcr of tlie New York State station at 

 (leneva have conducted a series of experiments upon tlic 

 sodium problem * with barley, tomatoes and peas, which 

 they summarize as follows : — 



1. A deficiency of Jivailable potash greatly depressed the yield 

 of the plant, even in the presence of an abundant suppl}' of soda 

 salts. A lack of soda in the presence of potash sufficient for the 

 plant's needs seemed to have no deleterious effect whatever upon 

 growth. 



2. Plants to which the necessary supply of potash was not acces- 

 sible took up more soda than when potash was present in abun- 

 dance. Soda may be substituted for potash in quantity when the 

 latter is lacking. 



3. While the substitution may take place in quantity, it evi- 

 dently cannot do so in function, as is shown by the limited growth 

 when the plants were deprived of potash, even though soda was 

 appropriated in increased proportions. 



4. The experiments incidently suggest the view that the real 

 need of plants for certain essential mineral constituents is not 

 even approximately measured by the proportions of these con- 

 stituents which the plant takes up. 



Our own experiments in this line at Kingston were begun 

 in 1894, and have been continued without interrui)tion ever 

 since. They embrace field and pot experiments with a 

 number of different kinds of plants, and are probably by far 

 the most extensive experhnents in this line ever conducted. 

 They are unique by virtue of embracing numerous field 

 trials made under normal soil conditions, which have been 

 carefully studied and controlled for nine years. The result 

 of the experiments to date may be summarized as follows : — 



1. No benefit, so far as concerns the yield of the crops, 

 was observed from the application of sodium salts so long as 

 an ample supply of assimilable potassium salts was present. 



2. The results confirm fully those of other experiments 

 elsewhere, to the effect that all of the functions of potassium 



* Bulletin No. 192, pp. 333-350, 



