48 



These comparisons make it evident that this soil still needs potash 

 in greater amount than either of the other elements of plant food. 

 Used alone it gives a more profitable result than that obtained on any 

 other plot. The gain from its use alone on plot 4 amounts to no less 

 than $14.66. Other plots gave larger crops ; but no other equalled 

 this one in point of profit on the fertilizer used. The result last year 

 was similar ; and it is true for both years that, even if labor be taken 

 into account, the plot where potash alone was used gave the largest 

 net profit. 



Both phosphoric acid and nitrogen this year produced larger 

 increase in crop than last. Both give larger increases when used 

 with the other two elements than when used alone or with either of 

 the other elements singly. The same was true last year : but the 

 differences this year are larger than last, indicating a more general 

 exhaustion of the soil. Phosphoric acid, indeed, when added to 

 nitrate of soda and potash produces a very profitable increase in the 

 crop and its average result is sufficient to produce a small profit. 



Neither land plaster, nor lime produce any very marked effect this 

 year, although, as in several other cases where lime has been used 

 two years, the increase this year is greater than last. 



Manure, used the second year upon the same plot, (the crop having 

 therefore the advantage of any unexhausted residue from the appli- 

 cation of last year, generally supposed to be considerable) produces 

 a crop of grain of exactly the same size as " complete fertilizer," and 

 two hundred pounds more stover. To secure these results, there 

 were applied in the manure this year three times the nitrogen that 

 was used in "complete fertilizer," one-twelfth less phosphoric acid 

 and about three-fifths the amount of potash contained in the " com- 

 plete fertilizer." 



In view of the results of tico years' tvork upon this soil, I cannot 

 doubt that with barnyard or stable manure it will pay to use muriate of 

 potash for corn upon this land. 



If fertilizer only is to be tised, I would recommend materials which 

 will supply per acre about 80 pounds of actwd potash, 30 pounds of 

 phosphoric acid and 20 pounds of nitrogen in available forms. 



