PARTS PER MILLION 
PLATE I.—MAXIMUM AMOUNTS 
OF NITRIC NITROGEN PRO¬ 
DUCED FROM THE DIFFERENT 
NITRIFIABLE SUBSTANCES 
PLATE II.—AVERAGE AMOUNTS 
OF NITRIC NITROGEN PRO¬ 
DUCED FROM THE DIFFERENT 
NITRIFIABLE SUBSTANCES. 
Check (NH 4 ) 2 S0 4 (NH 4 ) 2 C0 3 Dr’d Bid. 
Check (NH + ).,SO, (NH 4 ),C0 3 Dr’d Bid. 
Colorado Soils 
-Foreign Soils 
