j66 SOILS. 



It must not l?e forgotten that there are in the lowlands of 

 the arid region (river swamps or tules, seacoast marshes, etc.,) 

 soils in which surface soil and subsoil are differentiated as fully 

 as in the humid countries ; at least so long as they have not been 

 fully drained for a considerable length of time. In swamp 

 areas that have been elevated above the reach of overflow or 

 shallow bottom-water by geological agencies, even the heavy 

 swamp clays are fully aerated down to great depths, and roots 

 penetrate accordingly. 



Examples of Plant-growth on Arid Subsoils. The fact that 

 in the arid region the surface-soil conditions reach to so much 

 greater depths than in the East and in Europe, is so important 

 for farming practice in that region that experimental evidence 

 of the same should not be withheld. Of such, some cases well 

 established as typical of California experience are therefore 

 cited. 



It is well known that in the Sierra Nevada of California the placer 

 mines of the Foothills, worked in the early times, have long disappeared 

 from sight, having been quickly covered by a growth of the bull pine 

 (P. ponderosa}. Much of this timber growth has for a number of 

 years past been of sufficient size to be used for timbering in mines, and 

 a second young forest is springing up on what was originally the red 

 earth of the placer mines, which appears to the eye as hopelessly 

 barren as the sands of the desert. In this same red sandy earth not 

 unfrequently cellars and house foundations are dug, and the material 

 removed, even to the depth of eight feet, is fearlessly put on the garden 

 and there serves as a new soil, on which vegetables and small fruits 

 grow, the first year, as well as ever. In preparing such land for irrigation 

 by leveling or terracing no heed is taken of the surface soil as against 

 the subsoil, even where the latter must be removed to the depth of 

 several feet, so long as a sufficient depth of soil material remains above 

 the bedrock. 



The same is generally true of the benchlands ; the irrigator levels, 

 slopes or terraces his land for irrigation with no thought of discrimina- 

 tion between soil and subsoil, and the cultural result as a rule justifies 

 his apparent carelessness. It is only where from special causes a con- 

 solidated or hardpan subsoil is brought to the surface, that the land 

 when leveled shows " spotted " crops. Such is the case in some of the 

 "hog-wallow" areas of the San Joaquin valley of California, and in 



