32 



FIRST PRINCIPLES OF AGRICULTURE. 



Composition of Rich Wheat Soil. 



POUNDS PER HUNDRED. 



Carbon. 



Hydrogen 



Oxygen. 



12.67 



Silica 71.551 



Alumina. . . . 6.94 



Iron 5.17 



Magnesia ... 1.08 



Soda 0.43 



Sulphuric Acid . 0.04 

 85.21 



Elements which, though essential, are abun- 

 dantly supplied by the air and water. 



Elements which are either non-essential 01 

 are required by the plant in minimum 

 amounts. 



Nitrogen .... 0.121 



Phosphoric Acid . 0.43 I Elements absolutely essential, of which rela. 



Potash .... 0.35 J tively large amounts are required. , 



Lime 1.22J 



2.12 



Composition of Wheat Plant. 



- POUNDS PEB HUNDRED. 



Carbon .... 47.69 \ 



Hydrogen . . . 5.54 (- These are derived from the air and rain. 

 Oxygen .... 40.32 ) 

 93.55 



0.09 "| 



0.20 



0.31 



0.04 



0.06 



Silica 2.75 



3.45* 



Soda . . . . 

 Magnesia . . 

 Sulphuric Acid 

 Chlorine . . . 

 Iron . . . . 



These are abundantly provided by the soil, 

 and it is unnecessary to add them in any 

 case. 



Nitrogen .... 1.60 

 Phosphoric Acid . 0.45 

 Potash .... 0.66 



Lime 0.29 



3.00 



These the soil possesses only to a limited ex- 

 tent, and the deficiency must be supplied. 



