SOIL SURVEY OF SOLOMONS VILLE AREA, ARIZONA. 19 



PECOS SAND. 



The Pecos sand is a type of wide distribution, having- been recog- 

 nized by the Bureau of Soils in its surveys of the Pecos Valley, New 

 Mexico, and the Salt River Valley. Arizona. It consists of a uniform 

 fine river sand of a light-gray or whitish color, 6 feet or more in 

 depth, except where blown or washed over adjacent soil types. Small 

 areas of Riverwash, as well as gravel and streaks and patches of river 

 silt frequently occur within the limits of this soil type. It is under- 

 lain bj r sand and gravel. 



The Pecos sand occurs in one long, narrow area lying adjacent to 

 the Gila River, following the valley trough throughout the entire 

 area. It is one of the most easily recognized and uniform soil types 

 of the area surveyed. 



This soil occurs only in the river bottoms and is unmarked by rock 

 outcrops, bluffs, or prominent terrace lines. In its natural condition 

 the surface is more or less uneven, due to the action of water and 

 wind, and small dunes are still being formed. The characteristic 

 vegetation near the river channel consists of willow and cottonwood, 

 while upon the drier lands the prevailing growth is mesquite. The 

 soil is of a loose, porous texture, and very leachy, and much irrigation 

 water is lost from canals crossing it. 



The Pecos sand is derived from the granitic and volcanic rocks of 

 the mountains. These have weathered into finely abraded and water- 

 worn material, which remains in suspension in the swiftly running 

 water of the river for a considerable time, and is deposited as broad 

 sheets along the river flood plain during times of flood. The brisk 

 winds of the valley are constantly drifting this finer material about, 

 covering adjacent soil formations and extending the boundaries of this 

 type. This movement is greatly checked by the dense growth of 

 willow common upon the moister parts of this soil. 



Mica occurs in this soil in noticeable but not excessive amounts. 

 Alkali occurs in small quantities, but there is not enough of it to 

 impair the value of these lands for agriculture. But a small propor- 

 tion of the Pecos sand is at present cultivated, mainly because of the 

 difficult}' and expense of clearing off the willow, cottonwood, and mes- 

 quite, and leveling the land for irrigation. Small tracts are. however, 

 b ing cleared, and with thorough cultivation and frequent manuring 

 produce fair crops of grain, alfalfa, and fruit. 



The Pecos sand is somewhat deficient in organic matter and in some 

 of the important mineral plant foods. Owing to its leachy character, 

 the supply of plant food will become rapidly depleted if the soil is 

 not intelligently cultivated and fertilized. Frequent stirring greatly 

 assists this soil to retain moisture during dry seasons. It is easily 

 cultivated, and if properly farmed should make an excellent soil for 

 truck crops and small fruits. 



