232 SCIENTIFIC AGRICULTURE. 



ANALYSIS Continued. 



Potash, do. 



Soda, do. 



Phosphoric acid, do. 



Sulphuric acid, do. 



Carbonic acid, 



Chlorine, trace. 



Humic acid, 0.200 



Insoluble humus, 1.299 

 Water, 



100 



Chemically considered, a soil must contain all the inorganic 

 elements which plants require, and none that are injurious to 

 them. If the addition of a certain manure render a soil more 

 fertile, it is evident that the soil was deficient in one or more 

 of those substances which it furnished. If the addition of a 

 given manure or salt to a defective soil, fail to improve its fer- 

 tility, it is because enough of this substance is already present, 

 or because some other substance is wanting to render this 

 application available. A soil may sometimes show more or 

 less fertility for certain crops than analysis would indicate, on 

 account of some mechanical and physical conditions : in this 

 way the supply of certain elements may be cut off, although 

 they are present in the soil : the deficiency of others may also 

 be partially compensated by the same causes. 



