294 THE PRINCIPLES OF AGRICULTURE 



may be even more important, since plant- food 

 can be added if the soil has the proper physical 

 make-up. 



The soil is considered in six general phases: 

 (1) the contents of the soil, as to what it is and 

 what it contains; (2) the structure of the soil; 

 (3) the moisture in the soil; (4) the tillage or 

 amelioration of the soil; (5) the enrichment of 

 the soil by means of farm resources; (6) the 

 enrichment of the soil by means of commercial 

 or concentrated materials. 



Chapter 1 



At the outset, it is necessary to get a broad 

 view of the way in which soils have come to 

 be, and what the content of the soil is. As soon 

 the farmer develops a rational point of view on 

 this subject, the fields and hills and swamps 

 will have a new meaning to him. 



What are the sources from which all life and wealth are de- 

 rived? Which of these sources are beyond the control of man? 

 What is soil? What is the meaning of the word soil as contrasted 

 with land? 



Of what two kinds of elements is the soil composed ($2a, 27>)? 

 What is the physical basis of the soil? What is meant by organic 

 and inorganic (25)? What does the soil contain besides these 

 two classes of materials (25)? The pupils should be asked to 

 demonstrate the presence of inorganic matter in any soil (25c). 

 What is meant by weathering? How has the soil been formed by 

 means of weathering (26) ? What are the agencies by means of 



