598 T. J. MURRAY 



AMMONIFICATION 



Kelley (1915) found that anaerobic conditions greatly retard 

 the formation of ammonia from all materials except casein and 

 under anaerobic conditions the formation of ammonia has usu- 

 ally been found to be considerably less than under aerobic con- 

 ditions. Aeration (Kelley, McGeorge and Thompson, 1915) 

 stimulates ammonification but is not essential to the process as 

 it is to nitrification. 



Lohnis and Green (1913) found that aeration is of great 

 importance in the ammonification of organic matter. "The 

 most significant cause of variation appears to be that of aera- 

 tion. Ammonification as a whole proceeds much more rapidly 

 under aerobic than under anaerobic conditions, but it is believed 

 that aerobic conditions favor more specifically those latter stages 

 in the breakdown, which result in the formation of ammonia 

 itself." Later (Lohnis and Green, 1914) they report that while 

 aeration is not of preponderating importance ammonification of 

 such substances as flesh meal, bone meal and blood meal pro- 

 ceeds better under aerobic than anaerobic conditions. 



In my experiments the process of ammonification was tested 

 both in soils and in solution. One hundred grams of soil of 

 the different varieties was inoculated with 1 gram of the am- 

 monifiable substance. Blood meal sterilized with CS2 and sterile 

 casein (Brown, 1913) solution were used. For solution work, 

 Dunham's solution (1 per cent peptone plus 0.5 per cent salt) 

 and urea bouillon (nutrient bouillon and 1 per cent urea) were 

 used. In each case an easily and a less readily ammonified sub- 

 stance were used, casein and urea being easily ammonified. 



Anaerobic conditions were obtained with the soils by placing 

 them under a bell jar in a somewhat larger dish with pyrogallic 

 acid and caustic soda solution. The pyrogallic acid was placed 

 in the bottom of the dish, the soil in tumblers, and the bell jar 

 put on, the caustic soda solution added, and then some paraffin 

 oil. The bell jar was hfted slightly to let the caustic soda come 

 in contact with the pyrogallic acid. The oil prevented the mix- 

 ture from absorbing oxygen from the atmosphere. In solution 



