New York Agricultural Experiment Station. 191 



Table V. — Bacterial Counts op Field Soil. 

 Samples of Dunkirk silty clay loam. 



The results for 1913-14 are worth giving in detail. During this 

 year the weather was more favorable, samples were taken more 

 frequently, and laboratory conditions were well controlled. As 

 already mentioned, three series of tests were made: one from undis- 

 turbed field soil, fallow since 1911; one from aerated soil replaced in 

 the field in November, 1911, and held fallow; and the third from 

 soil aerated in November, 1913, and then replaced in the field. The 

 results of the analyses are given in Table V. In Graph VIII they are 

 plotted, together with the moisture content of the samples and the 

 average atmospheric temperature per week. 



Seven of these counts were made from frozen soil, and two others 

 from soil that had been thawed only twenty-four hours. All but 

 two of these nine counts were above thirty million; and these two 

 were taken only nine days after the first freeze of the winter. None 

 of the counts made from unfrozen soil were above thirty million 

 except two, both from the soil aerated in 1913, one on November 24th, 

 immediately after aeration, and the other on April 15th, when this 

 soil was found to be unusually moist and to have a musty odor 

 because of a heavy piece of burlap that had been accidentally allowed 

 to lie over it since the thaw. These exceptions occurred under such 

 abnormal conditions that they are easily understood and do not 

 affect the conclusion that the number of bacteria usually found in 

 frozen soil is greater than in the same soil under ordinary summer 

 conditions. 



