Mar. 24, 1919 



Ammonification of Manure in Soil 



325 



Table VII. — Plate counts of the microorganisms in sterile manured soil inoculated -with 

 a mixture of one spore former and two non-spore formers 



[Count indicates number of colonies per gram of soil] 



" Computed from the number of organisms in the infusion used for inoculation. 



The results as recorded in this series of experiments indicate quite 

 clearly that the non-spore-forming organisms, Ps. fluorescens and Ps. 

 catidatus rapidly gain the ascendancy over B. cereus when placed in 

 competition with it in sterile freshly manured soil. The vegetative 

 cells of B. cereus apparently soon sporulate and remain in the resting 

 condition. 



RELATIVE NUMBERS OF THE ORGANISMS IN QUESTION IN A SOIL 

 BEFORE AND AFTER ADDING MANURE 



Tables VIII, IX, 'X, and XI record data which show the relative 

 numbers of Ps. fluorescens, Ps. caudatus, and B. cereus in soil in which 

 no ammonification is occurring, and in the same soil after manure has 

 been added and decomposition is occurring rapidly. Table VIII ^ con- 

 tains the data obtained as the result of analyses of an untreated field 



1 The data given in this table were obtained by Conn in his earlier work. Much of it has already been 

 used in his soil-flora studies {8-1 1). 



