52 



Tlie teaching of the results brought out by these comparisons is plain. 

 This soil most needs j)Otash for the projitable production of corn and 

 this should be supp>lied to the full extent used in our experiments. The 

 increase due to phosphoric acid is also considerable ; but not sufficient 

 to account for nearly all that applied. This, though required, need not 

 be largely used. The nitrogen produces but an insignijicant increase, 

 and beyond possibly a little in available form to give the crop a start I 

 should not recommend its use on this soil for corn. Neither lime nor 

 plaster produce effects of any pariicxdar importance. 



The manure produces a somewhat larger crop and a slightly larger 

 increase than the "complete- fertilizer": but at an enormously 

 greater cost whether in money or in amounts of the chief essentials 

 of plant food supplied. I bring the figures together for comparison. 



Cost of manure, $25 ; Fertilizer, $12. 



Nitrogen in manure, 145.2 pounds ; " 25.1 pounds. 



Phosphoric acid in manure, 133.5 " " 48.2 " 



Potash in manure, 160.8 " " 81.6 " 



It will be observed that the fertilizer yields a much larger ajjparent 

 profit on its use than the manure. The latter, however, has undoubt- 

 edly left the land in better condition than the former. 



Far is it from my intention to imply that manure is not superior to 

 fertilizer in many respects. This is a well known fact. I wish only 

 to make evident that to secure given results requires a vastly larger 

 application of plant-food than in the case of fertilizers ; and farther, 

 to point out that for corn on this soil, the profit may doubtless be en- 

 hanced by using manure in small amount in connection with potash, 

 rather than by large applications of manure alone. This plan is to be 

 followed this year upon the general crop of the College Farm and the 

 result will, in due season, be reported. 



