EFFECT OF MOISTURE ON NITRIFICATION Si 



Exercise 17 

 Effect of Moisture on Nitrification 



1. Prepare eight 100-gram portions of field soil in clean 

 tumblers. 



2. Add to each J 30 milligrams of nitrogen in the form of 

 ammonium sulphate. 



3. Arrange thus: 



(a) I and 2, air dry. 



(b) 3 and 4, 15 per cent, moisture. 



(c) 5 and 6, 30 per cent, moisture. 



(d) 7 and 8, 45 per cent, moisture. 



4. After standing for one hour, mix thoroughly the con- 

 tents of the tumblers. 



5. Cover with Petri dishes and incubate for fourteen 

 days at 28° C. 



6. At the end of the period determine the nitrate nitro- 

 gen. 



' 7. Tabulate results. 



Table 22. — Effect of Moisture on Nitrification 



No. 



Moisture. 



Nitrate nitrogen in loo gm. of soil. 



Nitrified. 



Total. 



Blank 

 subtracted 



Average. 



I 



2 



3 

 4 



5 

 6 



7 

 8 



Per cent. 

 Air dry. 



do. 



15 



IS 



30 



30 



45 



45 



Mgm. 



Mgm, 



Mgm. 



Per cent. 



