IV. Soil Management Groups and 

 Crop Adaptations 



THE SOIL surveys show a total of more than 200 different soil types 

 recognized and mapped in the State (Appendix A, page 80). The differ- 

 ences between some of these are not highly significant in a discussion of 

 the broad uses and treatment of the land, however, and for the purposes 

 of this bulletin, the soils may be combined into five groups with different 

 geologic origins which include 36 Soil Management Groups. The five broad 

 subdivisions based upon geologic origin are: 



(1) Glacial uplands 



(2) Glacial outwash and river terraces 



(3) River bottoms 



(4) Marine and lacustrine materials 



(5) Miscellaneous materials 



Under each of these five broad subdivisions there are from 5 to 11 

 Soil Management Groups which are discussed separately in relation to 

 their crop adaptations. ^ You will note that crop adaptations are similar 

 in some Soil Management Groups, which would suggest that a reduction 

 could be made in the number of Management Groups. However, for the 

 purposes of this bulletin it was believed that separate Management Groups 

 by geologic origin would be fundamental for all present and predicted 

 future uses. Other uses may be made of these fundamental soil groupings 

 by new combinations designed to meet a specific objective, such as for 

 irrigation, drainage, forestry, or engineering soil mechanics. 



Soils Developed on Glacial Uplands 



About 83 percent of the State is covered with moderately coarse- to medium- 

 textured soils of glacial till ( uplands ) . These soils are formed on unsorted 

 materials containing particles of all sizes — from clay to boulders • — 

 but sand and stones predominate. This material is quite uniform in texture 

 at all depths. Bedrock lies at varying depths and outcrops of bedrock are 

 common. Except on steeper slopes, however, most of the material is from 

 3 to 10 feet or more in thickness over bedrock, and this provides enough 

 soil for plants to anchor themselves and to get the necessary water and 

 nutrients. 



About half of this area is very stony and is suitable primarily for 

 forestry and for wildlife and recreation. Much of the remainder is too stony 

 for cultivation but is suitable for pasture or for forestry with proper con- 

 servation practices. On some of this land, the number and size of sur- 

 face stones would permit clearing without too much expense. Only 11 

 percent of the acreage on glacial till is free enough of stones that it can 

 be cultivated regularly for crops or used for improved pasture. This rel- 



1 See Appendix B for a complete list of Soil Management Groups and their soil 

 types. 



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