As a means of obtaining a comparative statement of the 

 lour series, I have given below a table showing the average re- 



There can be no doubt as to the relative efficiency of series 

 3 and 4, since the amounts used would cost the same. The thir- 

 ty-two bushels increase represents an absolute gain due solely to 

 the use of mixed chemicals in place of the best of prepared fer- 

 tilizers. 



The cause of the increased efficiency is easily discerned, 

 for I assume that the prepared fertilizers above mentioned were 

 made from good grade materials, and that the plant food, shown 

 by analysis, was available. The following comparison of the 

 average chemical composition of the fertilizers in each series 

 needs little explanation. 



P 2 5 . K 2 0. N. 

 Series 3. (Complete chemicals,) % 10.2 1 1.7 2.5 



Series 4. (Prepared fertilizer,) % 11.6 3.0 3.0 



The conclusion is fully warranted that more potash is needed 

 than the prepared fertilizers furnish. 



MANURE AND CHEMICALS COMPARED. 



On Plot i manure was used, as has already been stated, at 

 the rate of seven cords, or $20.00 worth, per acre. That is, 

 twice as much in cost as of either of the fertilizers, and while 

 the yield is the largest of any plot, it is only four bushels ahead 

 of Plot 10, and if we compare the value of the gain per one dol- 



11 



