SOIL MANAGEMENT 49 



improves the structure of soils; those of coarse texture like 

 sand, by filling up the large spaces; those of fine texture like 

 clay, by separating the fine particles and also by inducing 

 granulation. 



Lime. The various benefits of lime were summed up in 

 the previous chapter in the discussion of soil amendments. 

 Attention is called to it here, because it is especially useful 

 in modifying soil structure and should therefore be considered 

 in any discussion of soil management. In dealing with sandy 

 soils a light application of lime tends to make them more 

 compact; in clay soils a heavy application promotes granu- 

 lation. 



VARIATION IN SOILS 



Soils differ greatly not only in different localities but in 

 parts of the same locality. There are all variations from 

 almost pure sand in very light soils to almost pure clay in 

 very heavy soils. 



The Bureau of Soils of the United States Department of 

 Agriculture has made a very complete study and classification 

 of the soils of the entire country; maps have also been pre- 

 pared showing the distribution of various soils in several 

 counties of each state. Several of the great agricultural 

 states, like the state of Illinois, have supplemented the work 

 of the Bureau by more extensive and detailed description of 

 soils within the state. These two sources of information 

 concerning the kinds of soils and their distribution are 

 mentioned because of their value for reference in the study 

 of soils in any particular locality. Other information to 

 assist in such study may often be obtained from the State 

 Agricultural Experiment Station, and sometimes from the 

 State Department of Geology. 



