Series, soil. A group of soils that are similar in profile characteristics 

 and in horizon arrangement. The soils of one series have developed from a 

 particular type of parent material. 



Soil. The natural medium composed of organic and mineral materials, suitable 

 for the growth of land plants on the surface of the earth. 



Soil association. A mapping unit used on general soil maps in which one, 

 two. or three major soils occur geographically in a characteristic repeating 

 pattern . 



Soil depth. Refers to the depth from the surface to the underlying bedrock. 



Deep. A soil more than 4o inches to bedrock. 



Shallow. A soil less than 20 inches to bedrock. 



Soil drainage. Refers to the rapidity and extent of the removal of water 

 from the soil, in relation to additions, especially by surface runoff and by 

 flow through the soil to underground spaces. 



Excessively drained. Water is removed from the soil very rapidly. 



Well drained. Water is removed from the soil readily but not 

 rapidly. 



Moderately well drained. Water is removed from the soil somewhat 

 slowly, so that the profile is wet for a small but significant 

 part of the time. The soil has a water table and is mottled in the 

 lower part of the profile. 



Poorly drained. Water is removed from the soil so slowly that it 

 remains wet for a large part of the time. The soil has a high water 

 table and is generally mottled from the surface downward. 



Very poorly drained. Water is removed from the soil so slowly that 

 the soil is permanently wet. The soil has a water table at the 

 surface and has a gray color throughout. 



Soil map. A map showing the distribution of soil phases, soil associations, 

 or other soil mapping \mits. 



Detailed. A soil map in which the kinds of mapping lonits are mainly 

 phases of soil series. Scale of soil map is generally 4 inches equals 

 one mile (l:15,84o). Used for operational planning purposes. 



General. A soil map in which the mapping units are mainly associa- 

 tions of soil series. Scale of soil map is 2 inches equals one 

 mile (1:24,000), 1 inch equals one mile (1 :62,500) or smaller. 

 Used for broad scale and general planning purposes. 



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