ELEMENTS 



OF 



FARM PRACTICE 



CHAPTER I 



SOILS 



Soil, from the standpoint of the farmer, is that por- 

 tion of the earth's surface in which plants grow. It is 

 composed of small particles of rock, as grains of clay and 

 sand, and decayed and decaying plants. 



Origin. — We are told that at one time, many, many 

 years ago, the earth's surface was all solid rock, and that 

 the wind and water and frost have been able to break off 

 little pieces of rock to make soil. These little pieces of 

 rock are called clay when very fine, sand when a little 

 coarser than clay, and gravel when quite coarse. In the 

 mountains, or where there are very large stones or boulders, 



Figure 1. — The action of vegetation, water and the weather gradually causes the 

 disintegration of solid rock. 



