16 



Report of the Massachusetts State Board of Agriculture for 1875-6, 

 states (by inference) that fifty bushels of shelled corn and the natural 

 proportion of roots, stalks, leaves and cobs contain : nitrogen, 64 

 pounds ; phosphoric acid, 31 pounds, and potash 77 pounds. These 

 figures were the result of actual determination of the proportion 

 existing between grain and all other parts of tiie plant and calculations 

 based on average statements of composition. Figures obtained by 

 myself by calculations based upon more recent American analyses 

 applied to the proportion existing in most of our experiments between 

 grain and stover show the amounts of these ingredients in fifty 

 bushels of grain and the usual amount of stover to be about as follows : 

 nitrogen 91 pounds, phosphoric acid 29 pounds, and potash 63 pounds. 



Though these two sets of figures are not alike there is a general 

 agreement in the relative proportions of the three ingredients. The 

 differences are in part due to the fact that I allowed a smaller propor- 

 tion of stover to grain ; in part to the fact that different analytical 

 results were used. 



Now as has been stated the fertilizers used in tliese experiments 

 supplied per acre: nitrogen, about 24 pounds; phosphoric acid, 69 

 pounds and potash, 72 pounds. Here then is nitrogen enough 

 according to Prof. Stockbridge for only about 19 bushels of corn, 

 phosphoric acid enough for about 110 bushels, and i)otash enough for 

 about 47 bushels ; or according to my figures respectively, for about 

 13, 119 and 57 bushels. It would evidently, then, be unreasonable to 

 expect as large an increase from the relatively small application of 

 nitrogen as from the larger applications of phosphoric acid and potash. 

 It is significant, however, that in no case in this experiment was the 

 increase in crop large enough to account for all of either of the 

 ingredients under consideration. The largest increase seemingly due 

 to nitrogen, 9.6 bushels, is considerably under the lowest estimate of 

 quantity of crop for which the supply of this element is adequate, 

 viz. : 13 bushels. 



Jt is evident that we recovered in the increase of the crop only a 

 comparatively small proportion of the nitrogen applied and the same 

 is true of phosphoric acid and potash in whatever manner used. The 

 result with nitrate of soda might very likely have been better had it 

 been applied in fractional dressings during growth instead of all 

 before planting ; but it cannot be supposed, in view of what is known 

 of the behavior of potash and phosphoric acid in the soil that any 

 considerable loss occurred through applying all of the fertilizers con- 

 taining them before planting. 



