1919] Pendleton: A Study of Soil Types 411 



Han ford fine sandy loam. — The MgO content of the surface soil 

 varies from 0.97', •' to 2.'u'',. averaging 1.92%. The relative varia- 

 tion within this type is about that of the Diablo and San Joaquin 

 types. 



Comparing the average amounts of magnesium oxide in the sur- 

 face horizon of the several types, we find the San Joaquin with 0.5(1' , 

 the Altamont with 1.05%, the Hanford with 1.93%, and the Diablo 

 with 2.09%. The averages do not signify much, however, because of 

 the wide ranges within the types. Therefore as regards magnesium 

 the types are neither distinct nor are the soils within the type 

 closely similar. 



Table 25 — Magnesium as MgO 

 San Joaquin Sandy Loam 



Phosphorus as P 2 O r , 



Diablo clay adobe. — The variations in the P L .O r , content in the 

 samples of this type are relatively small, from 0.092% to 0.162' . 

 with 0.108% as the average (tables 26, 27, figs. 11-14). 



Altamont clay loam. — The range of variation in the amount of 

 P 2 0- is large, from 0.031% to 0.265%. the largest quantity being eight 

 times the smallest. The average is 0.132% . 



