1914] Loughridge: Humus and Nitrogen in Calif ornia Soil Columns 219 



Pajaro Valley. — The soil of the valley proper is a dark loam, 

 while along the river are adobe clays and clay loams, the latter 

 being largely devoted to sugar-beet culture. The valley loam is 

 alone represented in the soil column series. It was taken from 

 the apple-growing section on the Watsonville side of the valley. 

 Another column of soil was taken from Watsonville Heights, 

 one mile northwest of the town. At a depth of eight feet a mass 

 of decomposed granite was reached. Both columns were taken 

 by Mr. F. E. Johnson. 



Table 23. — Humus in Soil Columns from near Watsonville, 



Santa Cruz County 



Sum of per cents 8.82 



Average per foot .74 



Upper 3 feet :* 



Sum of per cents 3.24 



Average per foot 1.08 



4.61 .04 



5.31 .06 



Range of most annual plant roots. 



The soil of the valley is deeper than that of the Heights, but 

 the percentages of humus in the first foot and in the upper three 

 feet are not as great; neither is its humus so rich in nitrogen. 

 The total amount of humus in the Pajaro Valley column is very 

 good in its distribution downward and this, with the sandy loam 

 nature of the soil, gives encouragement to the deep rooting of 



