108 



L. T. SHARP 



In alkali soils Nos 1 and 2 there is striking ammonification 

 power, possibly due to a stimulating effect of the alkali salts 

 which have been diluted to such extent that they are no longer 

 inhibitive. It appears from Lipman's^^ results that Na2C03, up 

 to comparatively large amounts, stimulates ammonification in 

 soils, NaCl and Na2S04 however fail to stimulate at the quan- 

 tities used, and possibly smaller quantities of salts would give 

 evidence of stimulation. Qualitative tests indicated that little 

 carbonate was present and that most of the sail: in soil Nos. 

 1 and 2 was white alkali. No other large differences in ammo- 

 nifying power occur, possibly due to elimination processes by 

 which all but the highly resistant spore bearing organisms were 

 destroyed. Each soil therefore contains an ammonifying flora 

 of predominantly spore-bearing organisms which are Ukely to be 

 of the same physiological efficiency. Prolonged drying seems to 

 equalize the ammonification power of soils, irrespective of their 



TABLE 2 



Ammonia produced from 0.5 gram of -peptone in three days incubation 



NO. OF SOIL 



AMMONIA FOUND 



NO. OF SOIL 



AMMONIA FOUND 





mg. 





mg. 



1 



33.3 



6 



31.8 



2 



48.1 



7 



25.6 



3 



27.7 



8 



31.8 



4 



27.3 



9 



38.7 



5 



28.5 







original bacterial content. There is no apparent relation between 

 the ammonification power and the number of organisms. Soil 

 No. 2, with 60,000 organisms, produces almost twice as much 

 ammonia as soils with nearly ten times as many bacteria, possi- 

 bly owing to salt effects previously mentioned. It is strikingly 

 apparent in these figures that the physiological efficiency of the 

 organism is the determinant factor in establishing its economic 

 agricultural value, suggesting at once great opportunities for 

 developing a highly efficient soil flora, by scientific and practical 

 inoculation of the soil with organisms of eminent physiological 



" Centblt. f. Bakt. 33: 55. 1912. 



