SOILS OF THE EASTERN UNITED STATES AND THEIR USE XIX, 



THE WABASH CLAY. 



GEOGRAPHICAL DISTRIBUTION. 



The Wabash clay is a widely distributed type of soil found in the 

 alluvial bottom lands of the Mississippi River and of its principal 

 tributaries. In the narrow bottom lands of the smaller streams the 

 individual areas of the type are usually small, but in the broad 

 bottoms of the Mississippi itself, and of its greater confluents, con- 

 siderable areas of the Wabash clay are frequently encountered in 

 single bodies. Areas of the type have been mapped in 23 different 

 soil-survey areas found in nine different States, and aggregating a 

 total of 419,915 acres. 



Wherever the dark upland prairie soils are carried down into the 

 drainage channels of the principal rivers they are sorted out and 

 their coarsest particles deposited to form the loams and silt loams of 

 the bottoms. There will also be found areas where the silt, and 

 particularly the clay particles, have accumulated to constitute the 

 Wabash clay. Such areas may be encountered along all of the major 

 streams in the central prairie region and for long distances to the 

 southward along the lines of deposition, particularly of the Missis- 

 sippi Eiver. Thus areas of the Wabash clay are encountered as far 

 east as Ohio, as far west as Nebraska, and from these regions south- 

 ward toward the Gulf of Mexico. 



CHARACTERISTICS OF SOIL, AND SUBSOIL. 



The surface soil of the Wabash clay is a drab, dark-brown, or 

 black,, heavy clay loam, having an average depth of about 6 inches, 

 although not infrequently extending to a depth of 12 inches or more. 

 When wet this surface soil is a stiff, sticky, plastic clay, which ad- 

 heres to the moldboard of the plow or to other tillage implements. 

 This surface soil will crack and granulate as the water evaporates, 

 forming large or small crevices, which sometimes have a depth of 4 

 or 5 inches and a width of one-fourth inch or more. In the areas in 

 which the content of finely divided organic matter is high, and where 



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