New YorK AGRICULTURAL EXPERIMENT STATION: / , 239 
: : 
reversed. With the pots receiving soda the proportion of potash 
was but slightly higher than in the first series, but rather more 
soda was present. The percentage of lime and magnesia seems 
to increase with the decrease of potash and vice versa. 
Dr. Augustus Voelcker,” has conducted field experiments with 
crude German potash salts and common salt on mangolds. 
Mangolds were grown upon a light sandy soil, the first series of 
plats receiving no fertilizer, the next common salt and the third 
crude potash salts, containing 24 per ct. K,SO,, 12 per ct. 
MgSO,, 47.8 per ct. NaCl. 
In speaking of the yield the author says:—“ Making due allow- 
ance for the natural variation in the productive powers of dif- 
ferent parts of the same field, common salt, it will be noticed in 
every instance, gave as good results as an equal weight of the 
more expensive crude potash salts. The larger dose of salt pro- 
duced a greater increase than the smaller.” 
“As the crude potash salts used contained twice as much 
common salt as sulphate of potash, and common salt gave as 
much increase as an equal weight of crude potash salts, it is 
more than doubtful whether the potash in the latter had any 
share in increasing the crop on the plats dressed with crude 
potash salts.” 
A study was made by Smets and Schrieber™ of the potash 
needs of various Belgian soils as well as the possibility of the 
replacement of part of the potash by soda. On some soils the 
soda seemed to have no action; on others if the potash content 
was not too smal] there was an increase of the crop. In the 
presence of a larger quantity of potash the soda seemed to have 
no action. 
Prof. S. W. Johnson™ in making what is undoubtedly a very 
| just review of the data bearing upon the use of potassium and 
sodium by plants, ‘places potassium as’ among the elements 
absolutely essential to the life of agricultural plants. Concern- 
ing sodium Prof. Johnson says: 
2 Jour. Royal Agr. Soc., 3: 86 (1867). 
23 Biedermann’s Centralblatt, 28: 227. (1898.) 
*4*How Crops Grow. 
