168 University of Californin Publicaiions in Agricultuml Sciences [Vol. 1 



Comparing the organisms in any one given soil as a medium 

 we find some interesting facts. In the sandy soil, for example, 

 with dried blood B. vidgaHs is the most efficient ammonifier, 

 making available or transforming into ammonia 24.36 per cent 

 of the nitrogen present. With tankage, B. mesentericus shows 

 the highest efficiency, transforming 32.52 per cent of the nitrogen 

 present into ammonia. With cottonseed meal, B. tumescens is 

 paramount, yielding an amount of ammonia equivalent to 24.30 

 per cent of the amount of nitrogen present. With fish guano, 

 B. vulgaris again manifests its superiority over the other organ- 

 isms by changing 13.09 per cent of the nitrogen present into 

 ammonia. When bat guano is used, B. mycoides stands distinctly 

 superior to all others, as above shown, by transforming 36.06 per 

 cent of the nitrogen present into ammonia. In the case of sheep 

 and goat manure there is but one efficient organism and that is 

 B. megatherium, which transforms 24.97 per cent of the nitrogen 

 present into ammonia. Lastly when peptone is used Sarcina 

 lutea stands pre-eminent, and when all materials are compared, 

 regardless of whether they were used in all soils or not, the last- 

 named organism makes the record for availability by transform- 

 ing 41.98 per cent of the nitrogen present into ammonia. There 

 are thus six organisms out of the fifteen which make records in 

 one and the same soil but with different forms of organic matter. 

 One of the six stands superior in the cases of two nitrogenous 

 materials, namely dried blood and fish guano, and that is 

 B. vulgaris. 



Comparing the same organisms with the same nitrogenous 

 materials, above used, except the last three named, in the clay- 

 loam soil, we find that with dried blood B. profeus vulgaris is 

 most efficient, transforming 6.9 per cent of the nitrogen present 

 into ammonia. With tankage, B. tumescens is pre-eminent and 

 transforms 12.74 per cent of the nitrogen present into ammonia. 

 With cottonseed meal, Streptothrix, sp., is superior, transforming 

 12.84 per cent of the nitrogen present into ammonia; and lastly 

 with fish guano. B. megatherium is again pre-eminent, trans- 

 forming 11.66 per cent of the nitrogen present into ammonia. 

 ^Ve see again, therefore, that in one and the same soil, with four 

 different materials, four different organisms make records for 



