32 



CALIFORNIA FRUITS: HOW TO GROW THEM 



closely related. The soils are highly charged with iron to the extent 

 of from seven to over twelve per cent, which being finely divided, 

 imparts to them the intense orange-red tint. The soil of the foot- 

 hills agree with the soils of the valley in having a good percentage 

 of lime, while the supply of potash and phosphates, as well as of 

 organic matter, is smaller, and sometimes low, though never ap- 

 parently inadequate for present productiveness, in the presence of 

 so much lime. 



Along the base of the foothills of the Sierra there is in Fresno, 

 Tulare, and part of Kern country, a narrow belt, irregular in width, 

 of partly red and partly black clay or adobe, so highly calcareous 

 as to break up, when dry, into small fragments, producing a con- 

 dition that has received the name "dry bog." It is upon this that 

 many of the citrus orchards of the Porterville and Mt. Campbell 

 districts are chiefly grown. A white, calcareous marl sometimes 

 occurs beneath this soil at varying depths, inducing chlorosis or 

 yellowing of citrus leaves, owing to its impervious nature which 

 does not allow of good drainage and therefore kills the roots through 

 suffocation and acid production. Westward of this "dry bog" land 

 there is a belt of reddish or brown loam soils, corresponding to those 

 similarly located in the Sacramento Valley, but generally more 

 clayey, and hence frequently designated as adobe by contrast with 

 the very sandy soils of the valley at large, although properly they 

 should be classed simply as clayey loams. This belt is eigth to ten 

 miles wide in middle Tulare county and narrows to the north and 

 south. Here these lands have a gentle slope of ten to twenty feet 

 per mile from the base of the foothills, and appear to be underlaid 

 at a depth of twelve to fifteen feet by water-bearing gravel. The 

 soil is a reddish, more or less sandy, loam, changing little in its 

 aspect for several feet. Its adaptation to fruit is shown by the prod- 

 ucts of the Lindsay region. 



CLAY SOILS 



Thus far a very small area of true adobe* soil has been employed 

 in horticulture. There is a great difference in the character of what 

 is known as adobe in different localities. Its color varies, as the 

 popular terms "black waxy," "black," "brown," and "gray" adobe 

 indicate. Its physical condition and chemical composition also 

 vary greatly. The black adobe of the east side of the Sacramento 

 Valley is easily tilled as compared with the gray adobe on the west 

 side, which is very refractory and often largely impregnated with 

 alkali. To render soil of adobe character useful for fruit growing, 

 this tendency to dry out and crack, thus allowing evaporation from 

 below as well as from the surface, must be overcome. The discussion 

 of this point belongs to the chapter on cultivation. Adobe soils are, 

 as a rule, rich and durable and therefore promise long fruitfulness 



*This name has been erroneously applied to the loam commonly used in the construction 

 of abode houses. Agriculturally, it means "a heavy clay soil," such as could not be used in 

 building. 



