SOIL SURVEY OF KIMBALL COUNTY, NEBKASKA. 15 



which has been carried on in this region it has been named the 

 OgalhUa formation. 



Recent-alhivial material, consisting of fine sand and silt overlying 

 gravel derived from the Ogallala formation, has been laid down in 

 the valley of Lodgepole Creek, and the valleys of the larger draws 

 have been partially filled by relatively coarser alluvial wash to a 

 thickness of 5 to 15 feet. A small deposit of alluvial-fan material 

 is spread out at the mouths of the draws entering the Lodgepole 

 Valley, and considerable recent-alluvial material is found at the 

 bases of practically all the steeper slopes. There are also in places 

 thin deposits of grayish or yellow very fine sand and silt on the 

 slopes at the bases of the bluffs inclosing Lodgepole Valley, which 

 appear to be wind deposits. 



The soil separations that have been made bear a close relation to 

 the different lithologic phases of the Ogallala formation and to local 

 differences in topography. 



The extent and character of the weathering determined by the 

 conditions of a semiarid climate have had a marked effect upon the 

 color, structure, and lime content of the soil. The prevailing color 

 of the soils is light brown at the surface, with grayish or pale-yellow- 

 ish subsoils. In general the soils have a loose, friable structure, 

 although the heavier types are moderately compact at the surface. 

 The material is generally calcareous, particularly in the subsoil, and 

 shows an alkaline reaction, although there is no surface manifesta- 

 tion of injurious alkalies and no appreciable injury to plant growth 

 from this cause. The organic-matter content is apj^arently low, 

 compared with that of the more humid sections in the eastern part 

 of the State. 



It is estimated that about 85 per cent or more of the county would 

 be arable land if supplied with sufficient moisture. Under the lim- 

 itations of normal rainfall about 55 per cent of the area is suitable 

 for cultivation under dry-farming methods, provided the crops are 

 chosen with regard to the soil and climatic conditions. 



In the system of mapping employed by the Bureau of Soils the 

 soils are grouped in series on the basis of common characteristics 

 in color, structure, and origin, and the series are subdivided into 

 types on the basis of texture, or the relative proportion of different- 

 sized mineral particles. Five series, including 12 types of soil, in 

 addition to Eough broken land, are recognized in Kimball County. 

 One type is represented only by a phase. 



The Sidney series comprises upland soils in the northern Great 

 Plains region. It is characterized by light-brown surface soils and 

 a lighter colored, usually light-gray or pale-yellowish, subsoil. The 

 subsoil material is highly calcareous, and the surface soil is mod- 

 erately so. The subsoil is loose and friable or mealy, and in the 



