SOIL COMPOSITION 



99 



In commenting on his study of Michigan soils, Doctor Kedsie 

 said: 



"Chemical analysis of the soil is of value in determining whether the soil is 

 capable of fertility or the contrary; also in determining the measure of its 

 possible fertility. 1 There are certain ash elements which are absolutely nec- 

 essary for plant growth, in the absence of any one of which vegetable growth 

 is impossible; if the supply is relatively limited, plant growth will be limited 

 correspondingly. Hence, chemical analysis of a soil is of importance in deter- 

 mining possibility of fertility and of the relative fertility which may be secured 

 under favorable conditions. . . . Chemical analysis will not always dis- 

 tinguish between a fruitful and an unfruitful soil. A soil may be unproductive 

 for physical reasons, though it may still contain all the chemical elements of 

 fertility." 



The Michigan wheat-belt soils include several different soil types, 

 but among the nine soil samples analyzed from that area, the poor- 

 est contained 2600 pounds of acid-soluble phosphorus, or 500 pounds 

 more than the average of the best Illinois soil. More than four 

 times as much phosphorus is contained in the average Michigan 

 wheat-belt soil (when these samples were taken) as is now con- 

 tained in the common soils of southern Illinois. 



A preliminary general survey of Wisconsin soils (Whitson, 

 Wisconsin Agricultural Experiment Station, Annual Report for 

 1905, pages 262-270) outlines seven different great soil areas in 

 that state: 



(i) The unglaciated area of the southwest quarter (extending 

 into northwestern Illinois) with three subdivisions in which residual 

 sands, sandy loams, and clay loams, respectively, predominate; 

 (2) the early, and (3) the late glaciations (each in two divisions based 

 upon the underlying rocks), occupying largely the remaining 

 three fourths of the state, and covered with glacial till, with little 

 or no loess deposit; (4) separated sand areas of glacial origin, as 

 in the south-central, extreme northern, and northwest parts of the 

 state; (5) a loessial area covering a strip of upland along the 

 Mississippi ; (6) " red clay " areas of lacustrine origin between 

 Green Bay and Lake Winnebago and on the Lake Superior shore ; 

 and (7) the scattered swamps of muck and peat. 



But few analyses of Wisconsin soils have been reported. An 



1 Italics by C. G. H. 



