EFFECT OF MOISTURE ON NITRIFICATION 



53 



Exercise 17 

 Effect of Moisture on Nitrification 



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

 tumblers. 



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

 ammonium sulphate. 



3. Arrange thus: 



(a) i and 2, air dry. 



(6) 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 



