No. 4.] 



KEEPING UP FERTILITY. 



99 



Averages of Special Fertilizers. 



Nitrogen 

 (percent). 



Phosphoric 



Acid 

 (per Cent). 



Potash 

 (per Cent). 



Twenty-one potato fertilizers, 

 Four corn fertilizers, . 

 Four grass fertilizers, . 



2.7 

 2.8 

 3.9 



10.4 

 12.4 



8.9 



5.7 

 4.0 

 4.9 



These figures are computed from figures given in the last 

 annual report of the State Experiment Station, and every 

 analysis for these crops except one for potatoes and one for 

 corn was included ; these varied so widely from the others 

 that it was thought best to omit them. 



I left them out because they contained so much potash 

 they were not fairly representative. In taking the amount 

 of phosphoric acid I have taken the total. Some w^ould say 

 I ought to have included only the available phosphoric acid ; 

 but the available in most special fertilizers is a very large 

 proportion of the whole, and I thought it best to take the 

 whole. 



From the same report I take the following figures : — 



Relative Proportion of Phosphoric Acid, Potash and Nitrogen. 



