Alfalfa in Kansas. 225 



lent in distance, until he passes out of the zone throughout which clover 

 will not grow, and into a zone where clover grows luxuriantly and is a 

 common crop. 



No sooner had I begun the study of the geology of Kansas than I 

 observed that the outcropping of our limestone masses formed zones 

 trending north and south, corresponding closely with the zones throughout 

 which red clover would grow luxuriantly, while the zones of no clover lie 

 in between the zones of limestone soils. It is now well understood that 

 the growth of leguminous plants in general, including all the clovers, is 

 helped greatly by the growth in the soil of friendly bacteria which draw 

 nitrogen from the air. Acid soils kill these friendly bacteria, so that 

 clovers grow very poorly in all acid soils. 



The limestones of Kansas form great beds outcropping on the east in 

 irregular lines at the surface, and dipping back to the west at a very low 

 angle. In between these limestone shelves are great beds of shales and 

 sandstones. Kansas soils in general are made from local rocks by 

 weathering agents acting upon them in place. Therefore, the soils made 

 from weathering the limestones form narrow zones stretching across the 

 state from north to south, and the soils made from weathering the shales 

 form zones lying in between the limestone soils. 



The accompanying block map of Kansas shows the relations of shale 

 and limestones to each other, and how and why we have these zones of 

 limestone soils alternating with shale soils. 



Now it happens that the Kansas shale beds have in them large quanti- 

 ties of the well-known mineral, pyrite, a double sulphide of iron, which 

 by oxidation produces large quantities of sulphuric acid as the shales 

 weather into soils, and such soils, being acid in character, will not let the 

 friendly bacteria grow, and so the clovers can not grow. 



The presence of lime makes it possible for alfalfa or clover to grow. 

 It is, therefore, desirable for the farmers of the state to have a clear and 

 definite statement put before them of how and where they may obtain 

 lime for liming their acid soils. 



For more than twenty years the Geological Survey of Kansas has 

 been studying and mapping in detail the location of the various lime- 

 stone formations within our state. The accompanying map is an 

 abridgement of other maps already published in the Geological Survey 

 reports. It is intended to show that the limestones of the eastern part of 

 the state particularly, and of the western part to some extent, cover 

 such large areas that a farmer at almost any place will have to haul or 

 transport his lime but a short distance. 



CHARACTER OF KANSAS LIMESTONES. 



The limestones of Kansas have been studied very extensively, not only 

 with reference to where they occur, their thickness, their general position 

 and other geological features, but their chemical composition as well has 

 been studied in sufficient detail so that one may speak with a certainty 

 regarding their chemical composition. It is one of the surprising features 

 or facts of nature that our limestones should be so nearly uniform in 

 composition. The hard limestones in the eastern part of the state, which 

 are so abundant, have not enough difference in composition throughout 



