Jan. 13, 1919 



Nitrates, Nitrification, and Bacteria of Acid Soils 



37 



contained the largest numbers of microorganisms developing moldlike 

 colonies, and the fully saturated soils gave culture plates containing 

 the smallest numbers of spreading moldlike colonies. 



NiTRATEvS AND NITRIFICATION IN RELATION TO BACTERIAL COUNTS 



Lime increased both nitrification and bacterial counts. A study of 



Plates I to 4 shows that the increases in bacterial numbers can be asso- 



Fig. I.— Graphs showing the relation of aerobes and anaerobes to nitrification of five add Soils with 

 and without lime and fertilizer treatments. 



ciated principally with the aerobic small, round, entire colonies on the 

 petri plates. Figure i shows the relations between aerobic and anaerobic 

 bacteria and the nitrates after incubation for the cropped, limed, and 

 fertilized soils kept at optimum moisture content. The nitrates after 

 incubation varied directly with the aerobic bacteria. The aerobic 

 count and nitrates after incubation show that it is the increased number 

 of aerobic organisms that are to be associated with increased nitrifi- 

 cation. 



