48 HATCH EXPERIMENT STATION. [Jan. 



trolled the product. The crop was very light, however, 

 even upon the best plot, which was at the rate of 116.9 

 bushels per acre, upon the plot receiving nitrate of soda and 

 dissolved bone-black. Upon the plots receiving these two 

 fertilizers and muriate of potash the crop amounted to only 

 16.3 bushels per acre. Here is strong evidence that the 

 muriate of potash has produced in the soil of this field con- 

 ditions absolutely prejudicial to the growth of the onion. 



Last year this field was in potatoes under the same sys- 

 tem of manuring, but with half the quantities employed this 

 year. The crop of potatoes on the nitrate and bone-black 

 was much heavier than on these two and potash, and in com- 

 menting upon this fact in my annual report I wrote : " The 

 apparent superiority of the phosphoric acid and nitrogen is 

 chiefly due to the fact that the plot to which these two ele- 

 ments alone were applied was for some reason (not believed 

 to be the effect of the fertilizer alone) nearly twice as great 

 as that upon any other plot. Had the crop where the pot- 

 ash was added to the nitrogen and phosphoric acid been 

 better or even as good as that where the phosphoric acid and 

 nitrogen alone were used, we should be justified in the con- 

 clusion that nitrogen and phosphoric acid are the elements 

 chiefly required. The crop where all three elements were 

 combined was, however, much inferior to that where the 

 nitrogen and phosphoric acid were used without potash. 

 We must, therefore, conclude that some disturbing factor, 

 at present unknown, influenced the results." 



In view of the similar relative results upon the two plots 

 under discussion this year, I am now forced to conclude 

 that I was mistaken last year in supposing that the superi- 

 ority of the plot receiving nitrogen and phosphoric acid 

 only was not " the effect of the fertilizer alone." 



I now believe that the muriate of potash has proved 

 actually injurious to the last two crops, and that the expla- 

 nation (the loss of lime which it causes) already suggested 

 accounts for this effect. 



