22 



FIELD OPERATIONS OF THE BUREAU OF SOILS, 1917. 



The results of mechanical analyses of samples of the soil and sub- 

 soil of Mohave fine sandy loam are shown in the following table : 



Mechanical anaUjses of Mohave fine saoidij loam. 



M CLELLAN LOAM. 



The surface soil of the McClellan loam typically consists of a 

 brown, gritty, light-textured loam, 10 to 20 inches in depth. It has 

 usually a slight reddish or purplish tint. The surface soil is more 

 compact and retains moisture better than the Mohave fine sandy loam 

 and sandy loam, but it lacks organic matter and has a tendency to 

 bake upon drying. Some fine gravel is generally present on the sur- 

 face and coarser material occurs along the small washes or drainage 

 ways. The soil conttiins much lime. 



The subsoil is a compact, highly calcareous, gritty loam, of light 

 grayish brown or pinkish-gi'a}' color. In places it is weakly cemented 

 and occasionally the deeper subsoil is a very compact, reddish, or red- 

 dish-brown loam or clay loam, not well adapted to root development. 

 Where it has been subjected to a high water table, the subsoil is often 

 grayish or grayish brown. The type is underlain by a deep gravelly 

 substratum. 



The McClellaa loam in this survey is subject to some variations in 

 texture, color, and depth. In several places south of Casa Blanca 

 small areas have a pronounced reddish brown color and others occu- 

 pjang slopes have a somewhat deeper surface soil than typical. 

 Small areas of lighter or slightly heavier texture are also included. 

 Much of the type in the western part of the survey contains alkali 

 in injurious quantities. 



The McClellan loam is one of the most extensive types in the area. 

 It occurs in all sections except the Gila River flood plain, in both 

 large and small bodies. 



The type represents part of an extensive plain, in which drainage 

 ways are poorly developed. It is generally level or gently sloping, 

 and is easily handled, such surface irregidarities as exist being of 

 little hindrance to irrigation or cultivation. Parts of the type are 

 well drained, but in general surface drainage is not well established, 

 and the subdrainage is retarded by the impervious or compact sub- 

 soil. The poorly drained areas contain more or less alkali. 



