222 



Bacteriological Department. 



[Bull. 161 



Part II. 



CONTINUATION OF THE EXPERIMENTS. 



On June 20, 1908, the experiments were continued, and de- 

 terminations were made according to the following plan : 



PLOT A (42x42 feet). 



SUBPLOT Al. 



Six samples to be taken every 

 14 days, volumetric method. 

 (Undisturbed.) (See note.) 



SUBPLOT Al. 



Six samples to be taken every 

 14 days, volumetric method. 

 (Unstirred.) 



A2. 



Six samples to be taken every 

 14 days, volumetric method. 

 < Stirred 2 inches.) 



A2. 



Six samples to be taken every 

 14 days, volumetric method. 

 (Stirred 2 inches on March 

 18 and June 20.) 



A3. 



Six samples to be taken every 

 14 days, volumetric method. 

 (Stirred 4 inches' on March 



18.) 



A3. 



Six samples to be taken every 

 14 days, volumetric method. 

 (Stirred 4 inches on March 

 18 and June 20.) 



A4. 



Six samples to be taken every 

 14 days, volumetric method. 

 (Stirred 6 inches on March 

 18.) 



A4. 



Six samples to be taken every 

 14 days, volumetric method. 

 (Stirred 6 inches on March 

 18 and June 20.) 



A5. 



Six samples to be taken every 

 14 days, volumetric method. 

 (Stirred 8 inches on March 



18.) 



A5. 



Six samples to be taken every 

 14 days, volumetric method. 

 (Stirred 8 inches on March 

 18 and June 20.) 



A6. 



Six samples to be taken every 

 14 days, volumetric method. 

 (Stirred 10 inches on March 

 18.) 



A6. 



Six samples to be taken every 

 14 days, volumetric method. 

 (Stirred 10 inches on March 

 18 and June 20.) 



NOTE. Eighteen samples taken by gravimetric method and eighteen 

 samples by volumetric method at the same time and place. 



One-half of each subplot in A and also one-half of each sub- 

 plot in B* were replowed to the same depth as on March 18, in 

 order to see if further stirring of the soil would increase the 

 number and activities of the soil organisms. 



The purpose of taking gravimetric samples was to obtain re- 

 sults which would afford a basis for a comparison of the two 

 methods of soil sampling. The gravimetric or weighed sam- 

 ples were secured from the same plots and at the same depth 



* Plot B, 42 x 42 feet, duplicate of Plot A. 



