Principal Dry-Farming Regions 



517 



bottom lands are of fine texture and lack organic matter. Water 

 penetration is slow but moisture is retained efficiently. Adobe soils 

 also are found in the bottoms. They are low in humus and nitro- 

 gen, baked in the dry season, and are difficult to till. They are rela- 

 tively fertile, however, and if plowed in the fall and exposed to 

 freezing- and thawing in winter are handled with less difficulty. The 

 most interesting lava soils within the timber belt are found near 

 Lakeside, east and north of Showlow Creek and around Flagstaff, 

 but soils little affected by lava occur at Scott's Flat, the mesa south- 

 west of Showlow, the Linden vicinity, and the Pinedale region. 

 Table VII records a chemical analysis of soil from a farm near 

 Linden, which had been under cultivation for two years. It shows 

 less nitrogen and humus than the lava soils around Flagstaff but 

 contains nearlv three times as much lime. 



TABLK VII. CHliMICAL ANALYSIS OP SOIL FROM NRAR LINDEN 



Another type, a scoriaceous soil, occurs on slopes of volcanic 

 cones and ridges. It is quite coarse and porous, absorbing water 

 readily and giving it up easily. This soil is composed of a mixture 

 of slag and pumice-like detritus, and is red, gray, or yellow in color. 

 The cinder soil east of San Francisco Mountain is worthless for 

 agricultural purposes and is barren, save for a few quick growing 

 annuals which utilize moisture from summer rains. 



In Tables VIII and IX are recorded mechanical and chemical 

 analyses of a typical lava soil sample, taken from a field at Cliffs in 

 which grain and potatoes had been grown for five or six years. 

 The lava soil contains more coarse material than the soil from 

 Pipe Springs Valley or from Linden, but the larger amount of clay 

 and silt insures lasting fertility. The percentages of nitrogen and 

 humus are relatively high, and there is a medium phosphoric acid 

 content. 



