16 FIELD OPERATIONS OF THE BUREAU OF SOILS, 1916. 



heavier types the surface material is commonly more compact and 

 coherent than the subsoil. The series is mainly residual in origin, 

 and in this county the soil material is derived almost entirely from 

 the Ogallala formation. The soils are well drained and are pro- 

 ductive under favorable conditions of rainfall. This series includes 

 practically all the upland or dry-land soils of the county, amount- 

 ing to 87.6 per cent of the total area. Five types are represented, 

 the gravelly sandy loam, fine sandy loam, very fine sandy loam, loam, 

 and silt loam. 



The Scott soils differ in physical characteristics from the Sidney, 

 chiefly in the more compact structure of the subsoil. The soil has 

 originated in the shallow depressions or basins which are a feature 

 of the upland plain. The material is principally colluvial from 

 adjacent slopes, which in this area are occupied by the Sidney soils. 

 It has been formed under conditions of poor drainage. The series 

 occupies a comparatively small area and is of minor agricultural 

 importance. It is represented only by the silt loam, calcareous phase. 



The Tripp series is characterized by light-brown and gray colors 

 in the surface soil and light-gray and pale-yellow colors in the 

 subsoil. The subsoil is highly calcareous. The series occurs on allu- 

 vial terraces above overflow along the streams in the western or 

 semiarid part of the Great Plains. In Kimball County the soil 

 material has been modified to some extent by wash from adjacent 

 slopes and by wind-blown material. The Tripp soils differ from 

 the Cheyenne principally in having less gravel in the subsoil and 

 therefore being less pervious. The land is well drained and is pro- 

 ductive under irrigation. Only one type, the Tripp very fine sandy 

 loam, is encountered in Kimball County. 



The soils of the Cheyenne series are derived from alluvial-terrace 

 material and from alluvial and colluvial wash which has partially 

 filled the valleys of streams and draws in the western part of the 

 Great Plains region. The soil is light brown at the surface, with a 

 grayish or pale-yellowish subsoil. The subsoil is gravelly or coarse 

 in texture and loose and porous in structure. It has a high lime 

 content. The land is well drained and lies above overflow. The soils 

 are droughty and are not very well adapted to irrigation where the 

 supply of water is small. Four types, the gravelly sandy loam, the 

 fine sandy loam, very fine sandy loam, and loam, are mapped in 

 Kimball County. These soils are of small extent. 



The Laurel series includes light-brown to pale-yellowish soils oc- 

 curring in the first bottoms along streams in the western part of the 

 Great Plains region. There is characteristically a porous gravel 

 stratum in the lower subsoil or the underlying material. These soils 

 have the same structure as the Cheyenne and the same mineralogic 



