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University of California Publications in Agricultural Sciences [Vol. 3 



Joaquin. The greenhouse pot cultures showed the effect of the much 

 higher nitrogen content in no. 14 in giving better color and growth 

 to the plants and especially to the grains. The increase of the nitrogen 

 in the surface of no. 23, as compared with the B and C horizons, 

 might be ascribed to the fertilizers applied to the orange grove where 

 this sample was collected; yet no. 24 is a truck soil which has been 

 fertilized to a considerable extent with barnyard manure. The nitro- 

 gen content of this type, as judged by the previous standards, is 

 quite inadequate. 



Compare the nitrogen content of the A horizons of the four types : 

 The Diablo has an average of 0.099%, with a range or from 0.084% 

 to 0.117% ; the Altamont has an average of 0.110%, with a range of 

 from 0.103% to 0.123% ; the San Joaquin has an average of 0.037%, 

 with a range of from 0.027% to 0.050% ; and the Hanford has an 

 average of 0.062%, with a range of from 0.045%? to 0.119%. Thus 

 the total nitrogen content of the several types is reasonably constant 

 within the type and rather distinct for the types. 



Table 12 — Total Nitrogen 

 Diablo Clay Adobe 



