CHAPTER X 



SOIL TYPES 



Classification of Soils according to their Physical or Chemical 

 Nature Geological Origin the Basis of Classification Vege- 

 tation characteristic of Various Soil Types : Physical Structure, 

 Chemical Composition, Natural Flora and Weeds character- 

 istic of Sands, Loams, Calcareous Soils, Clays, Peat, Marsh, 

 and Salt Soils Soil Surveys, their Execution and Application. 



Perhaps the question of the greatest practical import- 

 ance in connection with the scientific study of soils 

 is their classification into certain types defined by 

 their physical or chemical properties, and the alloca- 

 tion of these types to their appropriate areas, so as to 

 obtain a soil map of any given district. Despite 

 disturbing factors, to which allusion will be made later, 

 certain types of soil persist over wide stretches of 

 country, and are characterised not only by a general 

 resemblance in chemical or physical constitution, but 

 by a corresponding similarity in the natural flora they 

 bear, and their appropriateness to certain crops. The 

 constancy of the soil types is the result of a common 

 origin from the same kind of rock, and the difficulty 

 lies less in recognising the types than in drawing 

 boundary lines, so imperceptibly does one class shade 

 off into another. The only classification that can be 

 at all general, is one based upon the physical structure 



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