38 RURAL CALIFORNIA 



soil, but refers to the structure. There are clay 

 adobe, clay loam adobe, and loam adobe, although 

 the latter is very rare. The name is given to any soil 

 which on drying shrinks markedly and breaks into 

 blocks with wide cracks between. An adobe struc- 

 ture is undesirable because the soils dry out, not only 

 from the surface but also from the sides of the wide 

 cracks. The adobe soils are difficult to till and 

 maintain in the proper state of granulation, but with 

 good farming methods a good structure can be main- 

 tained. These soils are very rich, giving high yields 

 of the crops that are adapted to such heavy soils, 

 especially grains and grasses. 



"The recent transported soils occupy level to 

 sloping positions, and are readily put in condi- 

 tion for irrigation farming. They are productive 

 and are desirable above all the other soils of the 

 state. 



"The old transported soils form about one-third 

 of the arable soils of California. These soils occupy 

 undulating or rolling topography with some hilly and 

 broken areas. They have subsoils that are distinctly 

 heavier and more clayey than the surface soils, and 

 over one-half of their area is underlaid by hardpans 

 at depths of from two to four feet below the surface. 

 In most cases the material beneath the hardpan is 

 loose soil very similar to that above the hardpan, and 

 if the pan is broken by dynamite or other means, 

 irrigation waters and plant roots may readily work 

 down into the underlying soil mass. In such cases 

 the hardpan is not a serious factor as it ordinarily 



