92 A YEAR IN AGRICULTURE 



debt and from which he must eke out a miserable existence. 

 We should know at the outset that the soil is full of life and 

 science, and that without it we could not be living in this 

 world today. Most of our food, clothing, and shelter comes 

 directly or indirectly from the soil. 



Formation of the soil. We are so familiar with the soil 

 as we see it that most of us do not stop to think that it was 

 ever different. But it has really taken a long time for nature 

 to form what we know as the soil, and in so doing she has 

 employed wonderful agencies about which we shall write. If 

 we were to examine a sample of soil with a strong magnify- 

 ing glass, we would find that it is made up largely of fine 

 particles of rock. Mixed with these particles in varying 

 quantities are dark materials which are called organic mat- 

 ter, or sometimes humus. A closer examination will show 

 that the organic matter is simply the remains of plants and 

 animals which have formerly grown on the land, and which 

 have partially decayed or rotted in the soil. We find, then, 

 that the soil is composed of small particles of rocks mixed 

 with the remains of former plants and animals, and that by 

 far the larger part consists of these rock particles. This 

 suggests the truth that the soil has been formed from the 

 solid rocks, such as are found beneath it. Geologists tell us 

 that at one time all the surface of the earth was solid rock; 

 at that time there was nothing like what we now know as 

 soil. These rocks contained all the elements necessary to 

 make soil and furnish food for plants, with the exception 

 of the elements, nitrogen, oxygen and carbon, which come 

 from the air. Just as it is necessary for the miller to grind 



