248 Report op the Crop Production. 



The nccessanj proportion of potash. — Obsorvations which the 

 writer has made in watcliing the growth of ph^nts in pot culture 

 with kno'wn supplies of plant food has led him to inquire whether 

 the practice of computing the needs of a crop on the basis of 

 what it contains of potash and certain other ingredients is 

 rational. Does the plant need all the potash it takes up? If 

 not how much does it need? In the experiments of 1898-1899 

 the peas grew as rapidly and matured as fully with .146 grams 

 of potash per pot as with 1.4C2 grams. Many facts have come 

 to light which go to prove that the proportion of mineral com- 

 pounds taken up by plants is much modified by the soil supply 

 of these compounds. This being the case, what is the minimum 

 proportion necessary for the fullest development of the plant? 

 This is an important question. A crop of potatoes may with- 

 draw 100 lbs. of potash from an acre of fertile soil, but if 50 lbs. 

 would have been sufficient it is greatly desirable that the farmer 

 should understand the fact. 



This problem is just now the subject of investigation at this 

 Station and it is hoped that by giving it extended study reliable 

 conclutiions may be reached. 



