SOIL SURVEY OF THE MIDDLE GILA VALLEY, ARIZONA. 23 



The type is used largely for pasture because of the lack of water 

 for irrigation. A desert growth of Atriplex or desert sage, mesquite, 

 creosote bush, cacti, and seep weed forms the principal vegetation. 

 "Where the soil is free from alkali and can be irrigated, alfalfa, non- 

 saccharine or grain sorghums, and other grains are produced. Al- 

 falfa and the sorghums give good returns, but the yields of other 

 crops are only fair. Garden truck, melons, peaches, apricots, and figs 

 are grown locally. Egyptian cotton is produced on this type outside 

 the area. The content of organic matter in this soil is low. oxidation 

 of humus being rapid. Liberal applications of manure or the turn- 

 ing under of gi-een crops is necessary for best results. 



The selling value of land of this type varies greatly, depending 

 upon the location and the facilities for irrigation. 



McClellmi loam, shallow pJiase. — The shallow phase of the Mc- 

 Clellan loam differs from the typical soil chiefly in the depth of the 

 surface soil. The soil section consists of (1) a layer of brown loam 

 or fine sandy loam, 3 to 6 inches deep, and (2) a layer of compact, 

 reddish-brown or brown loam weakly or intermittently cemented and 

 approaching a hardpan in general characteristics. Both soil and sub- 

 soil are calcareous. 



The principal areas of this phase are mapped along McClellan 

 Wash and southwest of Casa Blanca. It supports in general a 

 stunted vegetation of sage, seep weed, and dwarf cactus. A few 

 barren spots occur. The soil is level and poorly drained. It is over- 

 flowed frequently from the McClellan Wash, and occasionally re- 

 ceives seepage from the higher lying types. The unfavorable struc- 

 lure of the soil, the liability to overflow, and the accumulations of 

 alkali render the land of little value except for pasture, and none of 

 it is cultivated at present. 



McClellan loam^ sUty phase. — The silty phase differs from the 

 typical McClellan loam in having a larger content of silt in the upper 

 foot or two. and in having larger proportions of organic matter. The 

 soil consists of a dark-brown silty loam 5 to 24 inches deep, and the 

 subsoil of material like that of the typical soil, but somewhat more 

 porous. The excess of silt is due to the deposition of material carried 

 by irrigation or overflow waters. The soil is darker than the typical 

 McClellan loam. Parts of the phase are spotted with alkali. 



This soil is not very extensive. The principal areas are situated 

 several miles east and southeast of Casa Grande, and southeast of the 

 Casa Grande National Monument. Those east and southeast of Casa 

 Grande are elongated and form shallow drainage channels. The 

 phase lies lower than the adjacent soils, and in places receives run-off 

 from surrounding areas. The drainage is nevertheless good over 

 most of it. 



