28 CALIFORNIA FRUITS: HOW TO GROW THEM 



CLASSIFICATION OF CALIFORNIA SOILS 



Any attempt to classify the soils of California upon scientific lines 

 or even to describe them in their wonderful variety, according to 

 their geographical occurrence, would lead beyond the limitations of 

 at treatise upon the practice of fruit growing. Rather let an attempt 

 be made to designate certain grades of soil with brief characteriza- 

 tion of their leading features as they are related to the growth of 

 fruits. By such a course it may be made to appear that though the 

 soils of the State are predominantly light, deep and rich, and thus 

 eminently fitted for fruit growing, there are many degrees in the 

 possession of these characters or any of them, in local soils, and upon 

 this individual manifestation they rate all the way from perfection 

 to defectiveness. Let a classification proceed, then, upon a descend- 

 ing scale. 



Light, Deep Loams. Admixture of clay with enough coarse 

 materials to secure permeability to air and water, ease in culvation, 

 deep root penetration and free drainage of surplus water, produces 

 soil of the highest adaptability to the growth of fruit trees and vines. 

 These soils are popularly known as loams. They are designated as 

 sandy loams, medium loams, and clay loams, according to the pro- 

 portion of clay commingled with the sand or coarse materials. 



Professor Hilgard devised the following nomenclature of soils 

 based upon their content of clay ; sandy soils, less than 5 per cent of 

 clay ; sandy loams, from 5 to 10 per cent ; ordinary or medium loams, 

 from 10 to 15 per cent ; clay loams, from 15 to 20 per cent ; clay soils, 

 from 20 to 50 per cent of clay. 



The coarse materials are sand grains of various sizes or rock par- 

 ticles in various degrees of disintegration. The fine materials are 

 clay and rock powder, commonly designated as fine silt. Loam soils 

 may result from deposits by flowing water or may consist of debris 

 but little removed from local rock disintegration. They include a 

 wide variety of materials, but agree in the possession of striking 

 adaptability to fruit culture. Some of the leading instances of such 

 soils may be cited. 



Loams of the Valley Plains. On the east side of the Sacramento 

 Valley low ridges and swales at right angles to the river's course 

 come in from the foothills, forming a gently undulating plain with a 

 fall of from fifteen to twenty feet per mile, sometimes right up to 

 the river channels. Nearly all the soils of the east side have a red- 

 dish tinge, showing the admixture of the red foothill soil and demon- 

 strating, by the way, that all these lands are well drained. In cuts 

 ten to twelve feet deep, made by the sloughs, the reddish plains loam 

 is seen to reach from six to ten feet in depth, being then underlaid by 

 gravelly substrata. The width of this class of profusely fertile valley 

 land, east and west, varies considerably, according to the meander- 

 ings of the rivers. Away from the water courses, the higher lands 

 of the valleys are largely red or yellow loams, sometimes clayey and 

 difficult of cultivation unless taken just in the right condition, some- 

 times gravelly and apt to dry out unless the natural water supply is 



