SOIL RELATIONS 245 



258. Other large cereal areas. That the plains of 

 Roumania and Hungary, noted for their cereal crops, are 

 practically an extension southwestward of the Russian 

 chernozem, has been mentioned. The hard kerneled 

 wheats of these plains compete in quality with those of 

 the Russian portion, and have even a greater reputation 

 in foreign markets. Other areas particularly adapted 

 for cereal cultivation lie in different parts of Siberia, in 

 the Indo-Gangetic plains of India, and in Australasia. 

 There are smaller districts even in forested areas which, 

 except for soil acidity, have natural cereal adaptation, 

 so far as soil conditions alone are concerned, such as the 

 prairie lands of Mississippi, Arkansas, and Alabama, and 

 the Clarksville and Hagerstown loams. Soils not well 

 adapted may often be made so by certain amendments 

 discussed in chapters XIV-XVI. 



259. The subsoil. The similarity of surface soil 

 and the lower layers in prairie soils is a fact commonly 

 observed. The change in composition and structure is 

 often very slight for many feet in depth. The richness in 

 plant-food of the lower layers has been shown by analyses 

 of Alway (1909). Lime is particularly abundant as a 

 subsoil constituent, and often increases in proportion to 

 depth. This condition is a fortunate one, and seen to be 

 practically necessary in connection with the nature of the 

 rainfall. As pointed out by Alway, the slight rainfall 

 in the Great Plains often cannot be correlated with the 

 crop production of a particular season, in view of the 

 known water requirement of the crop, without consid- 

 eration of the water conserved in the lower soil layers 



author for the United States Department of Agriculture, and 

 analyzed by the Bureau of Soils, except in cases of analyses made 

 by Ladd, Alway, and Shutt. 



