94 



PRINCIPLES OF AGRICULTURAL CHEMISTRY 



water conditions, which is largely influenced by the physical com- 

 position of the soil. 



Similar relations between physical character and crop adaptation 

 were traced in England by Hall. 1 He found very heavy soils 

 generally used for pasture. Wheat soils are heavy. Barley soils 

 are lighter than wheat soils, potato soils are still lighter. Hop 

 soils are somewhat like barley soils. Fruit soils are lighter than 

 hop soils. The different kinds of fruit have their own require- 

 ments. Waste soils are characterized by large amounts of coarse 

 sand, small amounts of clay and fine silt, an acid reaction and 

 absence of calcium carbonate. 



Analyses of typical soils used for various crops in the area 

 studied by Hall are shown in the table. The reader will notice 

 that the groups of soil particles are different from those else- 

 where mentioned in this chapter. 



The subsoil is generally heavier in texture, or contains more 

 clay, than the surface soil. This is largely due to the action of 

 water moving the finer particles of the soil into its lower portions. 



Soil Types and Soil Series. A soil type is a definite soil, with a 

 definite physical composition and other definite properties. It 

 may vary somewhat in different parts of the area, but in all 

 essential respects, it is the same soil. 



Soil series are groups of soil types related to one another 

 through source of material, method of formation, topographic 

 position, coloration, and other characteristics. The soil types in 

 the series vary chiefly in physical composition and other char- 

 acteristics caused thereby. A soil series, to be complete, would 



1 Jour. Agr. Sci., 1911, p. 206. 



