236 REePporT ON Crore PRODUCTION OF THE 
of sodium in one series and by calcium in another, the latter 
receiving no sodium. From the outcome of the experiments the 
author concludes; “ These results clearly show that sodium may 
fill a very important function in case of a deficiency in potas- 
sium and that it is therefore not to be regarded as an altogether 
useless plant constituent.” 
Extensive field experiments “ On the substitution of soda for, 
and its value in connection with, potash” have been carried on 
at the Rhode Island Experiment Station® since 1894. At the 
beginning, potash and soda were substituted for each other in 
different amounts and proportions, on 48 sixtieth-acre plats. 
Eleven varieties of plants were grown on each plat. The 
results indicate that soda is inferior to potash, the yields being 
greater by using potash without soda than by using soda with- 
out potash. Where potash in increasing quantities was added 
to a full amount of soda the yields generally increased; with 
increasing amounts of soda added to the full amount of potash 
less satisfactory results were obtained. | 
In 1895 the results’ confirmed those of the first year. 
The results" for 1896 were summarized as follows: “The 
inferiority of soda in the absence of potash, as compared with 
potash in the absence of soda, has become more strikingly mani- 
fest from year to year, in each of the three years of the experi- 
ment. * * * The addition of increasing quantities of potash 
to the full soda ration has increased the crop, in the order of the 
increased application of potash in each instance. Soda added 
to the potash ration has this year for the first time given indi- 
cations of the probable usefulness, which if not incidental can 
only become strikingly manifest, if at all, as the depletion of 
the assimilable potash on the soda plats increases.” 
°On the Substitution of Soda for, and its Value in Connection with, 
Potash, H. J. Wheeler, J. D. Towar and G. M. Tucker. R.I. Agrl. Expt. 
Sta. Rept. 1894, pp. 168-182; abstracted Hep. Sta. Rec., 7:849. 
*R. I. Agri. Expt. Sta. .Rept. 1895, pp. 205-214. 
4“R. I. Agrl. Expt. Sta. Rept. 1896, pp. 221-241, 
