VALLEY ALLUVIAL LOAMS 33 



those overrun by arid sand. Thl Joi\ of the Colorado River bottom 

 is highly productive, easily worked, being quite light. It is a highly 

 calcareous soil, and now, as the water of the Colorado River 

 has been made available for irrigation, is yielding rich returns for 

 cultivation. 



The valleys of the seaward slope of the Coast Range have mostly 

 gray, light, and silty, rather than sandy soils, quite similar in 

 appearance from Ventura to Humboldt county, though differing 

 considerably in composition, those of the southern region being 

 more calcareous, and apparently richer in phosphoric acid; as the 

 coast region consists for the most part of low ranges with inter- 

 vening valleys, the valleys are, as a rule, small, though a few show 

 considerable area. In such a country the soil surface shows wide 

 diversity within smaller areas than on the vast stretches of the 

 great interior valley; consequently, so far as soil goes, the coast 

 farms are often suited to a wider range of fruits than the interior 

 valley farms of similar size. 



ALLUVIAL OR SEDIMENTARY LOAMS 

 These soils have been considered from the earliest plantings 

 by Americans as par excellence the fruit soils of the great valley 

 of central and northern California. They occur along the courses 

 of existing streams, and extend back to variable distances, until 

 they merge into the valley loams, or adobes. These deposits are 

 considerably higher than the present beds of the streams, and are 

 sometimes described as "next to river bottom." They consist of 

 fine alluvium, with seldom any admixture of coarse materials. 

 These river soils are usually very deep and they are naturally well 

 drained. 



These deposits cross the valley in somewhat irregular courses ; 

 they are of greater or less width according to the drainage area 

 whence they have come. They vary also in depth, and taper down 

 on either side to the level of the red loam or adobe upon which 

 they have been deposited. Such strips are first chosen by the fruit 

 planters of the district in which they occur. In the valleys of 

 the rivers crossing the eastern side of the San Joaquin Valley, 

 there are, bordering the streams as well as Tulare Lake, consid- 

 erable areas of brown to blackish loam varying from heavy to light, 

 but for the most part easily tilled and exceedingly rich. Consid- 

 erable fruit has been grown for years on these situations, and some 

 kinds do well on these bottoms which do not show adaptation 

 to the plains. Some even of the higher lying portions of these 

 "black lands" support thrifty orchards without irrigation. The 

 wider stretches of alluvial soils in the upper part of the valley, as 

 in the Mussel Slough country and the Visalia region, for instance, 

 are notably well adapted to fruit growing. The occasional intru- 

 sion of alkali, which must be carefully avoided, is the chief obstacle 



