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



of its soils are shown in columns twelve feet deep taken respec- 

 tively from near Corcoran and Armona by Mr. P. E. Johnson. 



The Kern River delta farther south, with an area of about 

 290 square miles, is also timbered with oaks. It is represented 

 in the soil collection by a column taken three miles southwest of 

 Bakersfield. Water was reached in the seventh foot. 



Table 15. — Humus in Columns of Delta Lands, San Joaquin Valley 



Kings River Delta 



Kern River Delta 



Sum of per cents 2.64 



Average per foot .22 



Upper 3 feet : * 



Sum of per cents 1.00 



Average per foot .33 



6.98 .02 



7.10 .02 



3.63 

 .52 5.48 .03 



2.49 

 .83 5.90 .04 



* Range of most annual plant roots. 



It was anticipated at the outset that the delta loams of the 

 Tulare Lake and Bakersfield regions would be rich in humus in 

 at least the upper feet, because of their surface vegetation of 

 grasses and weeds and fallen leaves. But humification of these 

 has not taken place thoroughly, and we find that the amount 

 of humus in the upper three feet is not so large as in the sandy 

 loam soils of the plains. The surface soil of the Kern delta is 

 the richest in humus, which gives to the soil its per cent of 



