606 



T. J. MURRAY 



In the following two experiments nitrogen fixation was carried 

 out in solution under anaerobic conditions by placing narrow 

 bottles containing the mannite solution, inoculated with 5 grams 

 of soil, in the anaerobic apparatus and absorbing the oxygen 

 with pyrogallic acid and caustic soda solution. In one case thin 

 bottles containing a solution in which denitrification was going 

 on, were added. 



Experiment VIII. Anaerobic nitrogen fixation in solution, 

 grams per 100 cc. of solution. 



A 



Nitrogen in milli- 



Greenhouse 



Loam 



Clay 



Greenhouse 



Loam 



Clay 



NITROGEN AT END 



11.34 

 7.00 

 8.68 



NITROGEN AT 

 BEGINNING 



9.38 

 3.75 

 1.74 



1.96 

 3.25 

 6.94 



B 



5.62 



11.38 



4.58 



In Series B denitrification was going on in the same apparatus 

 in three other samples. The nitrogen fixing solution was inocu- 

 lated with 2 grams of the soils. There was more nitrogen fixed 

 in B, probably due to the fact that nitrogen was being con- 

 tinually given off in the denitrification experiments. This might 

 indicate that the more nitrogen present the more nitrogen is fixed. 

 It may be that as denitrification takes place in the soil some 

 part of this nitrogen may be again fixed immediately. Except 

 in the last experiment anaerobic conditions do not seem to favor 

 the production of more nitrogen than is produced under aerobic 

 conditions in solutions. Nitrogen fixation in solution proceeds 

 as well with or without the presence of air. 



Further experiments were carried out in soils by adding 1 

 gram of mannite per 100 grams of soil. Anaerobic conditions 

 were obtained with pyrogallic acid and caustic soda solution. 

 The total nitrogen was determined in 10 gram samples at the 

 beginning and end of the experiment. 



