SOILS OF THE EASTERN UNITED STATES AND THEIR USE XVI. 



THE DEKALB SILT LOAM. 



GEOGRAPHICAL DISTRIBUTION. 



The Dekalb silt loam is an extensive and important soil type, oc- 

 curring in the Appalachian Mountain and Plateau region of the 

 United States from northern Alabama to north-central Pennsyl- 

 vania and from the western part of Virginia to southern Indiana. 

 Areas of this soil have been encountered in 19 different soil surveys, 

 made in 8 different States, and a total area of 1,122,944 acres lias 

 been mapped. 



The widespread distribution of the type and its general occur- 

 rence throughout a broad area is thus indicated, and it is probable 

 that the Dekalb silt loam is both the most extensively developed and, 

 agriculturally, the most important soil type of the higher portion of 

 the Allegheny Plateau and Mountain sections. It is found chiefly at 

 the higher elevations, upon flat-topped ridges and extensive frag- 

 ments of the plateau not occupied by the crystalline rocks. 



CHARACTERISTICS OF SOIL AND SUBSOIL. 



The surface soil of the Dekalb silt loam is a mellow and friable 

 silt loam to an average depth of 8 or 10 inches, though not infre- 

 quently the soil has a depth ranging from 14 to 20 inches. The 

 color of the surface soil varies considerably in different areas where 

 it has been encountered, but is generally a gray, brown, or yellow. 

 The color is liable to be gray or brown in wooded areas, brown to 

 yellowish brown in well-tilled fields, and light gray or pale yellow 

 in fields which have been long under cultivation with little attention 

 paid to the maintenance and restoration of organic matter. 



The subsoil is usually a yellow or mottled yellow and gray heavy 

 silty loam which grades downward into a stiff and compact silty 

 clay loam or clay below 24 inches in depth. In many instances the 

 deeper subsoil is tinged with red or has an increasingly reddish color. 

 Only in poorly drained areas is the mottling of the deep subsoil 

 common, and in such instances the colors are pale yellow and drab, 

 gray, or almost white. The red coloration is always indicative of 



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