114 



POTATOES AND POTATO CULTURE 



Experiment III. 



How Much Potash can he Used Economically on a Potato Crop? 



In carrying out this exj^eriment four plots were set aside and 

 each handled in every respect similarly to those already alluded 

 to. The formula taken as a basis was: 3 per cent, nitrogeu, 

 8 per cent, phosphoric acid, and 10 per cent, potash. 



All four plots contained the same amount of nitrogen and 

 phosphoric acid, but differed in the amount of potash. 



Plot Xo. 1 contained no potash. 



Plot No. 2 contained 5 per cent, potash. 



Plot No. 3 contained 10 per cent, potash. 



Plot No. 4 contained 15 per cent, potash. 



The comparative yield of each plot was as follows: 



PLOT. 



1 



2 

 3 

 4 



Amount Potash per Acre. 



Yield per Acre— Bushels. 



Large. 



None 



5 per cent. (150 lbs.) . . 

 10 per cent. (300 lbs.) 

 15 per cent. (450 lbs.) . 



234S 



2641 



280= 



292i 



Small. 



Total. 



From this data it is shown that the larger amount of potash 

 had some bearing upon an increase in yield. The question now 

 to settle is whether this extra application produced enough 

 larger yield to j)ay for the extra expense of the potash. 



COMPARATIVE COST PER ACRE. 



