30 



EXPERIMENT STATION. 



[Jan. 



The amount of plant food furnished an acre, its cost, and the 

 profit realized by using the dilferent mixtures are shown in the 

 following table : — 



1 Represents the actual cost of chemicals. To these should be added the cost of mixing, which 

 will range from SI. 50 to $2 per ton. 



2 The late spring and the unusually dry summer were not favorable for a good corn crop. In 

 1911 on these same plots the average yield of the four plots was over 85 bushels per acre. 



' Based on the value of the crop at harvest time. 



* Represents the difference between the cost of chemicals and the value of the crop. The labor 

 question was not considered in this comparison because it was the same for all plots. 



6 The prices and formula for the corn fertilizer were obtained by taking an average of all the corn 

 fertilizers reported in the 1911 fertilizer bulletin. 



The composition of the corn fertilizers varies widely, and in 

 taking an average of all corn fertilizers, reported in our fer- 

 tilizer bulletin from year to year, we find considerable variation. 

 The percentage of phosphoric acid is not as high at the present 

 time as in former years. 



The tables show that in order to supply about the same 

 amounts of plant food per acre, it would be necessary to use 

 1,700 pounds of the average corn fertilizer. This at the aver- 

 age price per ton would cost over $28, It will be seen from 

 the figures representing the cost of the different chemical mix- 

 tures, and the crops obtained, that it would be necessary to 

 harvest a much larger crop on this fertilizer in order to insure 

 a profit as large as that shown for the other fertilizers. 



The prices used in these calculations were as follows: corn 

 on the cob, 60 cents per bushel; stover in the field, $6,50 per 

 ton; fertilizers at the current prices for 1912. 



