CHKMICAL KLlvMKNTS NKKDKn P.V PLANTS 9 



Ver cent. 



Carbon 45.0 



Oxygen 42.0 



Hydrogen 6.5 



Nitrogen 1.5 



Mineral compounds (ash) 5.0 



From the above analysis it is readily seen that carbon and 

 oxygen make up the largest proportion of plants. Let us ex- 

 amine the composition of some farm products that are familiar 

 to us, and find out if this same predominance of carbon and 

 oxygen -exists. ^ 



Carbon 

 Per cent. 



Oxygen 

 Per cent. 



Hydrogen 

 Per cent. 



Nitrogen 

 Per cent. 



Ash 

 Per cent. 



Clover hay 



Wheat kernel .... 



Fodder beets 



Fodder beet leaves 

 Wheat straw 



47-4 

 46.1 

 42.8 

 38.1 

 48.4 



37.8 

 43-4 

 43-4 

 30.8 

 38.9 



5.0 

 5-8 

 58 

 5.1 

 5-3 



2-3 

 1-7 

 4-5 

 0.4 



7-7 

 2.4 



6.3 



21.5 



7.0 



There is some variation in the composition of these farm 

 products but the carbon and oxygen constitute the largest amounts 

 of the elements present. 



This predominance of carbon and oxygen is due to the fact 

 that about nineteen-twentieths of the plants' food is obtained 

 from air and water, and the remaining one-twentieth is derived 

 from mineral compounds of the soil and soil water. In other 

 words the farmer only has to supply a small proportion of the 

 elements necessary for producing good crops.''' 



Acids and Bases. — The mineral elements that make up the a.^^h 

 of plants are not present in the free state but in various combi- 

 nations, as acids and bases. The acids and ba.ses of the mineral 

 elements of ash are : 



' Jordan. The Feeding of Aiii 



