Ivanderleck] 



BACTERIA OF FROZEN SOILS 



25 



Table lb. 

 Field plowed and manured in the Fall. 

 Average number of bacteria in millions on B. media and S. media at different depths. 



Table Ic. 



Field manured and plowed. Moisture content at different depths. 



Date. 



1916. 

 Nov. 14 

 Dec. 1. 



1917. 



Jan. 8 

 " 11 

 « 22 



Feb. 5. 



Mar. 1 

 " 8 

 " 22 

 " 29 



Apl. 12 

 « 19 



The diagrams on this plate and on the subsequent plates of the 

 other experiments are arranged as follows: 



Each diagram represents the results of the analyses of a definite 

 level, either 4", 8", 12" or 16". Above the zero line the moisture 

 variations are indicated by the dotted curve and the bacterial changes 

 by the solid black line. Below the zero line the frost penetration 

 in the soil in inches is represented by the solid line; the broken line 



