THE CLARKSVILLE-- SIM LOAM. 5 



pied by the Clarksville silt loam, its level to gently rolling surface 

 topography renders the internal drainage of the type deficient in many 

 areas. This arises from the fact that the elevated plateau areas, while 

 they may be well drained around their margins, are so extensive 

 that surface drainage has frequently not been well established over 

 the more interior locations of the wider stretches covered by the 

 type. The soft compact silty soil and dense silty loam or silty clay 

 subsoil are rather impervious to the percolation of moisture, thus 

 retarding the effective internal drainage of the soil and subsoil. 

 In many areas where the soil type has been encountered there are 

 sink holes and cavernous subterranean drainage ways which assist 

 materially in the proper drainage of the type. In such areas the 

 agricultural value of the land is frequently greater than in the more 

 level portions where this accessory drainage is lacking. 



The level topography of the Clarksville silt loam in general serves 

 to prevent excessive erosion. Near the borders of the type where 

 it breaks down over steeper slopes to the gorgelike valleys, which 

 frequently separate different areas of this soil, erosion is active 

 and in many instances excessive. Owing to the characteristics of 

 the soil and subsoil, however, the true silty loam and silty clay soil 

 is rapidly carried away, leaving an accumulation of the included chert 

 and flint fragments, and this frequently progresses to such an extent 

 that areas of the Clarksville silt loam are rapidly transformed by 

 erosion into areas of the Clarksville stony loam. This arises merely 

 through the removal of the fine-grained soil and subsoil material 

 at a rate more rapid than the rate of disintegration of the stony 

 fragments which thus accumulate to modify the textural character- 

 istics of the soil area. 



LIMITATIONS OF USES. 



The fine-grained texture and dense structure of the Clarksville 

 silt loam preclude the production of many special crops which are 

 suited to better drained and warmer soils. These same character- 

 istics also render the type well suited to the production of the small 

 grains and certain grasses, while not interfering seriously with the 

 growth of special classes of tree fruits. The Clarksville silt loam, 

 however, because of its texture and structure is a general-purpose 

 farming soil rather than one suited to special crops. 



Throughout its entire extent the Clarksville silt loam is usually 

 deficient in the amount of organic matter remaining in the surface 

 soil. This is shown by the rather uniform gray or ashy color of the 

 surface materials, and by the soft powdery texture of the soil, unmodi- 

 fied by the inclusion of fibrous organic matter. This lack of organic 

 matter also gives rise to undue compactness in the surface soil and 

 renders its tillage difficult unless the mechanical handling of the 



