New YorK AGRICULTURAL EXPERIMENT STATION. Doo 
represent the consensus of opinion among scientific men at the 
present time, current popular thought has been thrown more or 
less into confusion on these points by recent newspaper discus- 
sions over the substitution of soda for potash in feeding plants. 
This discussion was started and largely maintained by the late 
Andrew H. Ward and, aided by the press, he so persistently 
exploited his belief in the possibility of this substitution to the 
advantage of the farmer that he made more or less impression 
upon the views of the agricultural public. This writer wus able 
to present little or no experimental proof of his position, his 
arguments being largely assertions. In view of the situation it 
was thought wise to institute experiments touching this matter, 
not because of anything new in the scientific evidence advanced 
which should cause the question to be reopened, but rather to be 
able to throw into the argument more experimental data of 
recent origin. It is desirable before presenting the plan of these 
experiments and the results obtained, to review somewhat briefly 
the evidence furnished by past investigations, without attempt- 
ing, however, to compile a monograph on the subject. 
RESULTS OF PREVIOUS INVESTIGATIONS. 
W. Knop! concluded in regard to the growth of maize that in 
the first period of growth the plant may get along without soda, 
yet for the full development of the plant, soda must be added to 
the plant food. 
Hellriegel? studied the potash need of barley, using “ quartz 
sand almost potash-free,” and potash salts in quantities from 0 
to 282 parts per million of soil. He found that 47 parts per 
million was sufficient for the maximum growth. The use of 
larger amounts of potash did not seem to cause a greater yield, 
but the potash was taken up by the straw in larger proportions. 
Nobbe, Schroeder and Erdman? found that in a nutritive solu- 

1Abstracted in Jahrb. f. Agr. Chem., 4: 127. 
*Abstracted in Jahrb. f. Agr. Chem., 10:11T. 
SLandw. Vers. Stat., 18 :321 and 401, abstracted in Jahrb. f Agr. Chem., 
14 : 104. 
