412 University of California Publications in Agricultural Sciences [Vol.3 



San Joaquin sandy loam. — The variations in the P 2 5 content of 

 the surface soil are from 0.039% to 0.11%, with the average 0.068%. 

 The curve is fairly regular. The subsoils follow the surface in a gen- 

 eral way. The B horizon samples vary in the phosphoric acid con- 

 tent between 0.028% and 0.156%, and average 0.069%. The C sam- 

 ples vary between 0.03% and 0.109%, and average 0.067%. The 

 averages of the three horizons are seen to be almost identical. No 

 particular significance can be attached to the minor variations. 



Hanford fine sandy loam. — The P 2 0- content in the samples of 

 this type is very variable, from 0.195% to 0.819%., with the average 

 of 0.363%. The average of the San Joaquin sandy loam samples is 

 0.069%, of the Diablo clay adobe 0.108%, of the Altamont cla}' loam 

 0.132%, and of the Hanford fine sandy loam 0.363%. Except between 

 the Diablo and Altamont types these averages would show considerable 

 differences, if it were not that the samples frequently show such wide 

 departures from the averages. The ranges of the several types fre- 

 quently overlap. 



Table 26 — Phosphorus as P 2 5 

 (Surface horizon only) 



