192 University of California Publications in Agricultural Sciences [Vol. 1 



ten or twelve feet, the others being limited in depth either by 

 hardpan, coarse gravel, or other obstruction which prevented tlie 

 penetration of the soil auger ; sometimes the water-table at depths 

 of less than ten feet produced such a mushy condition in the 

 soil as to prevent its being removed by the auger. 



Gray Sandy Loams and Sandy Soils. — The greater part of 

 the San Joaquin Valley is covered with a grayish sandy, and 

 sandy loam, soil, u.sually deep and highly productive under irri- 

 gation or adequate rainfall. Some of them are highly charged 

 with alkali salts in small areas, but these salts can be removed 

 by proper means of irrigation and subdrainage. Calcareous and 

 black alkali hardpans are also found occasionally, whose injurious 

 effects can be corrected by proper treatment. 



From these lands we selected seven localities in five counties 

 from which to secure representative soil columns; three of these 

 contained large amounts of alkali salts and are given a separate 

 discussion. Each of the other columns was taken to a depth of 

 eleven or twelve feet, from the following localities : two miles 

 north of Exeter ; three miles west of Tulare ; one mile west of 

 Modesto ; and near Livingston ; taken by ^Ir. F. J. Kandolph. 



The soil from west of Tulare has a little more than 1 per cent 

 in the surface, and 2 per cent in the upper three feet, but the 

 others in the table fall far below that percentage, the ]\Iodesto 

 and Livingston soils being especially poor. Humus is found 

 throughout the entire column from three of the localities, and 

 contains fair percentages of nitrogen ; but the actual amount in 

 the soil itself is very small, except in the upper three feet of 

 the Tulare column. The Livingston soil is little else than sand 

 and is very poor in both humus and nitrogen. 



Gray Clay-Loam Lands. — The lands of the west side of the 

 San Joaquin Valley, derived from the rocks of the Coast Eange 

 and deposited from streams apparently more sluggish than came 

 from the Sierras on the east, contain more clay and are of the 

 clay-loam type of soil. They are more compact than are the 

 sandy soils, and should, therefore, contain more humus than the 

 latter. Three localities where the columns were obtained are on 

 the west side of the valley, one mile south of Tracy, five miles 

 southwest of Los Banos, and one mile west of ]\Iendota. 



