Nitrogen concentrations were averaged 

 grouped by soil series and site condit 

 sites were assumed to have been fertil 

 were counted as receiving minimum fert 

 therefore combined with virgin sites o 

 in the analysis. When Interfan areas 

 were analyzed separately from the main 

 soils in order to determine the extent 

 that took place. The average nitrogen 

 sites are given in Table 21. 



(depth-weighted) and 

 ions . All irrigated 

 Ized; dry-farmed sites 

 lllzatlon and were 

 f the same soil series 

 were so noted, they 

 body of alluvial 

 of natural leaching 

 levels for Individual 



TABLE ^1 



AVERAOEi' NITROGEN CONCENTRATIONS IN VIRGIN, IRRIGATED, 



AND DRY FARMED SOIL TROFILES ALONG THE WEST SIDE 



OF THE SAN JOA14UIN VALLEY 



1/ Average - depth welshled HO3-M In tile rone (3 - 10 feel). 

 ?/ Ph^BlOf^raphic poeltlone: BR - Dasln rite, RA - recent alluviun fan, 

 T/ Surface texiure: sc • sandy clay, el • sandy loam, cl • clay loaa, 

 fsl - fine sandy loan, sic - sllty clay. Is - loany sand, c - clay. 



■ older alluvial fan, T ■ terrace. 

 loan, scl - sandy clay loan. 



Variability of Nitrogen from Different Sites 



Average nitrogen concentrations within individual profiles 

 of different soil series varied from 0.0 mg/l to 23^ mg/l; 

 concentrations exceeding 400 mg/l were observed at depth in 



72 



