22 



A gric it Uural Cli emistry. 



present in least quantity compared with the requirements of that 

 crop. If a field of corn can obtain only potash enough for a half 

 crop, no more than this can be produced, no matter how much of 

 the other forms of plant food is present. 



The following table shows the ingredients, expressed as pounds, 

 in 1000 Ibs. of the matured corn plant, when the plant is to be 

 cut for shocking : 



Corn Plant 

 1000 Ibs. 



Water 

 793 



( Hydrogen 

 ( Oxygen . . . 



704.9 



f Organic matter 

 195 



f Nitrogen 2.9 



! Carbon . . . . 90.5 



Oxygen.. 88.1 



Hydrogen 12.' 



Dry matter - 



207 



Ash 12 



f Protein 18 



j Fat 5 



| Fibre 50 



[ Carbohydrates . . 122 



f Chlorine 0.4 



Potash 4.0 



Phosphoric acid. 1.2 



Lime ... 1.6 



Magnesia 1.4 



Iron oxide 0.3 



Sulphur trioxide. 0.3 



Soda 0.4 



Silica 2.4 



All the elements mentioned above as occurring in the ash, with 

 the exception of chlorine, are combined with oxygen. In the 

 table the names under ' * ash ' ' represent these combinations : pot- 

 ash is composed of potassium and oxygen; phosphoric acid of 

 phosphorus and oxygen; lime of calcium and oxygen; sulphur 

 trioxide of sulphur and oxygen. 



The table shows that three elements, hydrogen, oxygen and car- 

 bon, make up 98% per cent of the entire composition of the plant, 

 the remaining elements constituting only 1% per cent. 



