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SOILS AND THEIR USES 



production of crops. They may be classified according to fineness 

 into sandy, loamy, and clayey soils, according to the proportions 

 of sand, silt, and clay present. This classification is based en- 

 tirely upon the size of the inert particles present. A sandy soil 

 is coarse, loose and open. A clayey soil contains much silt and 

 clay, and is therefore very fine, close, and compact. Loams are 

 intermediate between these two extremes. 



If the soil particles are formed from the crumbling of limestone 



FIG. 62. Hillsides may be terraced for each row of orchard trees to prevent erosion. 



(F. A. Waugh.) 



they may be designated as limestone soils. They usually have the 

 characteristics of clay loams, but are darker in color. Peaty soils 

 are those which contain a very great proportion of vegetable matter 

 in a more or less perfect state of preservation. They may be 

 formed in bogs where the presence of water prevents decay. On 

 exposure to air the decay may be very rapid. The color is usually 

 black or dark brown. 



In like manner, other soils may be given special names referring 

 to special characters which they exhibit. 



