Soil-Group Divisions 87 



accumulation of aluminum and iron generally in this soil-group divi- 

 sion provides the derivation for the term "ped-al-fer." 



In the region where the pedalfers exist there is generally sufficient 

 rainfall for agriculture, but the soil tends to lose its nutrients. In the 

 extreme podzol type the interaction of the climate and vegetation is 

 such that solubles are rapidly carried away and the soil becomes 

 progressively poorer and more acid, whereas in the chernozem soil 

 fertility tends to be perpetuated. The contrast between the cherno- 



COVER OF 



GRASSES 



AND HERBS 



Organic matter 

 mixed with 

 mineral soil 



TRUE SOIL 



(Neutral to { 



slightly 



alkaline) 



Lime (CaCog 

 accumulation 



Fig. 3.11. Schematic vertical section through a soil of the chernozem group as 



representative of the pedocal soil-group division. The subdivisions of the soil 



profile are indicated in relation to the vegetation and the movement of soil water. 



The depth scale is representative, but varies greatly. 



