1918] 



Way nick: A Statistical Study of Nitrification in Soil 



245 



The samples were taken at the locations as shown in figure 1, the 

 diameter of the plot being one hundred feet. Each number in the 

 following table represents two samples, soil and subsoil, the latter term 

 being used for convenience in expression rather than to represent any 

 sharp line of demarcation between the two samples taken at any given 



i- 



Fie. 1 



place. All the surface samples were taken with a trowel to a depth of 

 six inches, an area having a diameter of approximately six inches being 

 included in each sample. The subsoil samples were taken with a three- 

 inch auger to a depth of twenty-four inches and, therefore, represent 

 the section from six to twenty-four inches in depth. All the samples 

 were placed in sterile soil bags as soon as taken, the total amount of 

 soil in each sample being about twice that necessary for the laboratory 



