Principal Drv-Fakmixg Rrcions 



519 



should be considered together. Probably 150,000 acres suitable for 

 dry-farming are included. Granite Mountains on the south and 

 west, and the Black Hills on the east and north almost completely 

 enclose these valleys. The two ]M-incipal drainage streams, Granite 

 and Willow Creeks, flow north and east, and in the rolling to- 

 pography of the valleys numerous floodwater courses have been 

 formed. All drainage courses converge near Del Rio, forming one 

 of the main tributaries of the Verde River. 



Rapid water erosion takes place in the flood season, and me- 

 andering of the larger streams causes depositions of great quantities 

 of sediment on either side of the floor of the valleys forming a very 

 fertile silt soil. A fairly coarse loam is found on the first mesa im- 

 mediately adjacent to the creek bottoms, and a gravelly loam occurs 

 on frequent knolls in the valleys, though neither of these loams is as 

 fertile as the silt soil of the bottoms. All three soil types are found 

 on the Prescott Dry-farm. Tables X and XI give the mechanical 

 and chemical analyses of the silt soil deposited in limited areas 

 along the stream courses of the Little Chino and Lonesome Valleys. 

 It contains a large percentage of nitrogen and humus, and is very 

 fertile. Tables XII and XIII give the mechanical and chemical 

 analyses of the intermediate loam on the Prescott Dry-farm. The 

 sample is typical of the prevailing soil type of the region. The high 

 percentages of silt and clay classify this soil as a fine loam. It is 

 permeable and retains moisture quite well. The percentages of 

 nitrogen and humus are fairly low, though the soil shows relatively 

 high fertility. 



TABLE X. MECHANICAL ANALYSIS OF SOIL FROM BOTTOM LAND, PRESCOTT 



DRY-FARM 



