550 University of California Publications in Agricultural Sciences [Vol. 1 



Nitrogen Content of the Grain 



It appeared of interest, in view of the foregoing, to determine 

 to what extent the soil's nitrate content, which was high through- 

 out, had influenced the nitrogen content of the dry matter. We 

 therefore determined the nitrogen content of the grain harvested 

 in a number of the series so as to obtain some idea of the direc- 

 tion taken by the effects of the nitrates, if any were exerted. As 

 a result of these analyses it was found that in the second crop 

 of the copper series the nitrogen content of the grain was in the 

 absolute from 0.14 per cent to 0.57 per cent higher in the case 

 of that grown on the "coppered" soil than in that grown on the 

 control soils. In the third crop of the copper series the nitrogen 

 content was from 0.05 per cent to 0.38 per cent higher in the 

 grain from the treated soils than in that from the untreated 

 soils. In the case of the second crop of the zinc series, the 

 nitrogen content of the grain was from 0.06 per cent to 0.64 per 

 cent higher in the grain of the treated than in that of the 

 untreated soils. In the third crop of the zinc series, the corre- 

 sponding figures ranged from nothing in one case, in which the 

 lowest concentration of ZnSO^ was used, to 0.42 per cent. Simi- 

 larlv in the case of the iron series, the range was from nothing 

 to 0.68 per cent in the second crop, and from 0.22 per cent to 

 0.50 in the third crop. No determinations were made in tlie 

 ease of the lead series, but analj'ses were carried out in the case 

 of the second crop of tlie potash alum series which indicated tliat 

 the grain of the treated soils was in most cases only very slightly 

 richer in nitrogen than that from the untreated soils, and that 

 the maximum increase did not surpass 0.09 per cent. 



On the whole, and leaving the potash alum out of consider- 

 ation, it seems that one of the results of stimulation of the 

 barley plant by tlie metallic sulfates in question was the increase 

 in the nitrogen content of the grain. At all concentrations of 

 all the salts tested, with only one or two exceptions, the grain 

 grown on the treated soils was richer in nitrogen than that on 

 the untreated soils. That this fact should be referable primarily 

 to the increased vigor of the nitrate formation in the treated 



