6o SOIL BACTERIOLOGY 



10. Tabulate results. 



Table 25 — Denitnfication in Soil 





Treatment. 



Nitrogen in 100 gm of sod 



No 



As nitrate 



Total nitrogen 





Be£?in 



End 



Loss 



Begin 



Fnd 



Los 



I 



2 



2 water control 

 do. 



Mgm 



Mgra 



AIgm 



Mgm 



Mgm 



Mgm 



3 

 4 



3 water 2 5 dextrose 

 do 















S 

 6 



Total water control 

 do 















7 

 S 



Total water 2 5 dextrose 

 do 















Exercise 25 

 Autotrophic Denitrifying Bacteria 



1. Prepare six tall tubes of Lieske's culture-medium 

 (m. 38). The tubes for this exercise should be at least 

 10 to 15 inches long and filled four-fifths full of the 

 culture-medium. 



2. Inoculate: 



(a) I and 2, uninoculated 



(6) 3 and 4, i gram of garden soil. 



(c) 5 and 6, I c c of sewage. 



3. Incubate the cultures for six to eight weeks at 28*^ C. 



4. Determine the total nitrate content of the different 

 cultures. 



