SOILS OF THE EASTERN UNITED STATES AND THEIR USE XIV. 



THE FARGO CLAY LOAM. 



GEOGRAPHICAL DISTRIBUTION. 



The Fargo clay loam is an extensive and important type of soil 

 which, because of the mode of its formation, is restricted within 

 rather narrow geographical limits. It is the most extensive single 

 type of soil which has been encountered in the Glacial Lake and 

 Terrace soil province, and a total area of 601,024 acres has been in- 

 cluded in six different soil surveys made in the States of Minnesota, 

 North Dakota, and South Dakota. The type owes its origin to the 

 extensive deposition of fine-grained lake sediments in the bed of the 

 old glacial Lake Agassiz, which occupied an extensive territory along 

 the boundaries of the present States of North Dakota and Minnesota. 

 It is also found in the glacial Lake Souris farther west in North 

 Dakota, and in the similar glacial Lakes Dakota, in South Dakota, 

 and Minnesota along the Minnesota River in southern Minnesota. 

 In addition to its occurrence in the beds of these larger extinct glacial 

 lakes, it is encountered in a multitude of smaller glacial lakes within 

 the area of these three States. The type is also known to extend 

 through central Manitoba and eastern Saskatchewan in the Domin- 

 ion of Canada. In fact, it is probable that the most widespread de- 

 velopment of the soil type is to be found north of the Dominion line 

 in these Provinces. 



In all of these localities the Fargo clay loam constitutes the great 

 spring-wheat soil of the Northwestern States and the western Cana- 

 dian Provinces. 



CHARACTERISTICS OF SOIL AND SUBSOIL. 



The surface soil of the Fargo clay loam is a deep, dark-brown to 

 black clay loam containing a perceptibly large quantity of organic 

 matter. This surface soil has a depth varying from 12 to 24 inches 

 in the various areas where the type is encountered. In the slight de- 

 pressions found within the type the surface material is often mucky 

 and of an intense black color to a depth of 4 to 8 inches. The subsoil 

 is in all cases a heavy silty clay or clay which not infrequently has a 

 definitely stratified structure. It varies materially in color, dependent 



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