CONDITIONS AFFECTING PRODUCTION OF NITROGEN. 



45 



desirable to know whether there has been any increase in nitrogen 

 per acre. Returning to the figures given by Balland it will be seen 

 that the wheat of 1848 produced on an average 163 kilos per hec- 

 tare, while that of fifty years later produced 171 kilos, an increase 

 of about 5 per cent in gluten per hectare, with an increase of 25 per 

 cent in yield. These figures an not, of course, be taken as strictly 

 accurate, as they are based merely on what M. Balland refers to as 

 the range of nitrogen content. 



Some data on this subject are available in the published records 

 of wheat improvement at the Minnesota Experiment Station. a 

 Yields and gluten content of improved varieties and of the original 

 variety from which the improved strains have been developed by 

 selection are given. The figures cover the same seasons for all 

 varieties, and the averages of six trials are reported for each, as 

 follows : 



In each case the new variety yielded more grain per acre, possessed 

 a lower gluten content, and produced more nitrogen per acre in the 

 grain. It should be explained that determinations of gluten and 

 baking tests were made of strains of wheat produced by the selection 

 of individual plants, and that the quantity and quality of the gluten 

 in these strains were considered in deciding which strain was to be 

 perpetuated. For that reason the gluten content of the improved 

 wheat is doubtless greater than it would have been if no attention 

 had been paid to those qualities. Incidentally it may be stated 

 that the quality of the gluten in these new varieties of wheat origi- 

 nated by Professor Hays is much better than that in the original 

 varieties. The difference between selection for gluten carried on in 

 this way and selection for gluten applied to the individual plant is 

 that the latter must increase many times the opportunity for devel- 

 oping a strain of desirable gluten content. 



Returning to the nitrogen production per acre, it is apparent that 

 it is slightly greater in the improved wheats, or at least is not less 

 than in the original varieties. This is encouraging, as it indicates 

 the possibility of increasing the production of gluten per acre. 



Minnesota Experiment Station Bulletin 63. 



